The American Naturalist.

ASSOCIATE EDITORS:

J. A. ALLEN, Pu.D., American Museum of Natural er er York.

E. A. ANDREWS, PH.D, Johns Hopkins University, B.

_ WILLIAM S. BAYLEY, PH.D., Colby University, rg

ambridge.

ALES HRDLICKA, M.D., U.S. National Museum, Washington.

D. S. JORDAN, LL.D, RER ee ersity.

CHARLES A. KOFOID, PH.D., University s os deis Berkeley.

J. G. NEEDHAM, PH.D., Zake Forest Univer.

— ARNOLD E. ORTMANN, PH.D., Carnegie A = Pittsburg.

D. P. PENHALLOW, D.Sc„F.R.M.S., McGill University, Montreal.

H. M. RICHARDS, S.D., Columbia University, New York.

^W. E. RITTER, Pu.D., University of California, Berkeley.

ISRAEL C. RU SSELL, LL.D., University of Michigan, Anm Arbor.

. ERWIN F. SMITH, S.D., U. S. Dee of Agriculture, Washingtons

LEONHARD STEJNEGER, ELB, ee Institution, Washington.

Euer. W. TRELEASE, S.D., Missouri Bota. St. Louis.

— -—.. HENRY B. WARD, PED, er of Nebraska, Lincoln.

^ .— . WILLIAM M. WHEELER, PH.D., American Museum of Natural History,

ae New York.

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THE RC

AMERICAN NATURALIST

AN ILLUSTRATED MAGAZINE

NATURAL HISTORY

VOLUME XXXIX

BOSTON, U.S.A.

GINN & COMPANY, PUBLISHERS

The Atbenzum Press

2995

Mo.Bot. Garden

SUS

INDEX.

ABNORMAL venous system in Nec-

turus

en v, wo. E

Acanthias and Raia, Muscles of . 891

Acmaa testudinalis, Biology of . . 325

Affinities of the genus Equisetum 273

Amber in eastern United States,

Occurrence and origin of 137

Anatomical changes in esit

. cylinder of hybrid "Umen ; ans

Angiosperms of 13

Angle at which stems e" iid

est geotropic res : 77

pores Synopsis i N ol ddr

n families and genera of . 293

Atilio, Mexican scale-insects

E the DM... S XN

BAKER, C. F. Fleas and disease 507

Baker, F. C. Notes on —

of Lymnza i . 665

Bangs, O., and Z Zappey, W. R.

Birds of the Isle of Pines . 179

Bees, Halictine, of A 89

Bees of the genus Diadasia . 741

Berry, E. W. Fossil gen and

: 345

Biological pee a in er 505

Biology of Acmaa

Müller . . pu -325

Birds of the Isle of Pines . . . 179

Blagden, Sir Charles, earliest

Rhode Island ornithologists . 397

Bones of the reptilian lower jaw 59

CAMPBELL, D. H. Affinities of

" . 273

. the genus Equisetum .

dii

PAGE

Carpenter, F. W. Reactions of

pomace fly to light, —— and

mechanical stimulation . 157

Catalpa, Anatomical eh inci-

dent to hybridization of eg

Chetopterus pergamentaceus, Com-

mensals in tu 37

Clark, A. H. Habits of "West

Indian whitebait ; | 348

Cockerell, T. D. A. Diadasia, a

genus of bees . 741

—— Halictine bees of Amilo 89

—— Mexican scale-insects of genus

Aspidiotus ; 45

Coe, W. R. iioii of North

American invertebrates. XXI.

The Nemerteans. Part 1 425

Collection vo en of zoó-

lo 779

buses in Mi of Chatop-

terus pergamentaceus

Contribution to our r knowledge o of

myxinoids .

Correspondence:

Baker, C. F. Fleas and disease 507

Dodge, C. W. Orton's —

' 995

Crabs, dini of the ON ‘Het

Miocen . 381

— ; Tebouldosikipe of

Cricket, "Habits of intima ie oe

Cushman, J. A. A new ostracod _

from Nantucket - 791

PAGE

er mam. stages in the

Lagen - 537

Fossil ere P the cay Head

Miocene. . 381

Klem on Bulsschkaiden : 754

——and Hende F.

enders

Fresh-water ridi podk "Wm New

Hampshire 147

Davis, B. M. Studies on the

plant cell 217, 449, 555, 695

Davis, a andersonii

and Rana virgatipes in New

Jany 2 o oso ico

Developmental stages in the La-

genidz uds a a acus a RO

Diadasia, a genus of bees . . . 74I

Diatoms, Movements of, and other

microscopic plants . . . . .287

Disease, Fleas and 507

EASTERN America, Forest centers

CF 1 2 42 5 4 4 a E

Eastman, C. R. Etymology of

common names of animals . . 269

Literature of Edestus . . 05

Echinostomum spinulosum, rur

fence una 94

Ecology of the willow cone i 8 59

Edestus, Literature of . s 3.408

Embryo of the angiosperms 13

Enders, H. E. Commensals in

tubes of Chetopterus pergamenta-

d 37

re Affinities e die genus La

Etymology of common names of

animals 269

FISH literature, Notes on recent 91

eas an ase . 507

Forest centers of eastern Ka 875

Fossil crabs of the Gay Head Mio-

. 381

Fossil grasses pu sedges - 345

Fresh-water rhizopods from White

Mountains of New Hampshire 147

GALL, Ecology of the willow cone 859

Gay Head Miocene, Fossil crabs

of . 38

' Klem

INDEX.

Genitalia of Lymnæa .

Geotropism of stems

Gilbert, N. C. ES of

E chinostomum passes

rasses and sedge sil

Greenland, A biological station in

Hanrrs of striped meadow cricket

abits West Indian whitebait

Halictine bees of Am

Hancock, J Habits a stud

meadow cricket .

Haynes, J. A. angie at ‘Which

stems show strongest geotropic

Jackson, D. D. Movements of

diatoms and other microscopic

DER s 1s s

Jaw, Bones of reptilian lower

KINGSLEY, end S. Bones of the

reptilian lower jaw

on Palaechinidden:

LAGENID&, Developmental stages

i. 5.5. 1 3

Larva and spat of Canadian oyster

Lateral vein of skate, Posterior

connections of . .

Literature of Edestus .

PAGE

. 665

response 77

Heindel, R. L Ecology of the

willow cone gall . 859

Henderson, W.P. See Cuien

J. A., and ——

Henriksen, M. E. A in

station in Greenland 505

Hollick, A. Occurrence a ori-

gin of amber in eastern United

States Ae cag a

Howe, R n Sir Charles

Blagden, earliest of Rhode

Island ornithologists i307

Hybridization of catalpa, Anke:

cal changes incident to 113

Hyla andersonii and nn virga-

tipes in New Jersey ; 795

INJECTION of skate . 365

Interrelationships of poe. 607

| Isle of Pines, Birds of . 179

INDEX.

E ~an F. B. Momentum in vari-

ea o s. Reus of the

titanothere peer x bw 4c RO

Lymnzea, Genitalia of . . 665

Lyon, H mbryo ot the

ee une A ws. i

MANDIBULAR and pharyngeal mus-

cles of Acanthias and Raia . 891

Marion, G. E. Mandibular aie

A muscles of Acanthias

s 91

Seni fé ‘Santos in ER

Collection of ud - 995

Megacerops, Restoration of . . 4

Mexican scale-insects of the ge-

nus Aspidiotus 45

Miocene, Fossil crabs ni G say Hoal 381

Momentum in v ion . 839

Movements of diatoms ind: other

microscopic plants . . S87

Muscles of Acanthias iid Raia . 891

Myxinoids, Contribution to our

knowledge of . . . . . .625

NATURAL and artificial gum

genesi

es Al ] venous ajiki

i 2214. 91

Nemerteans, Synopsis al ‘North

American . : 42

New RER RR: diis

opods from ite Mountains of 147

New ostracod from Nantucket. . 791

Notes and Literature : j

Anthropo! . 758

ogy .

Anthropology, Notes > . 760

Botany . à en: 681, u 850

Botany, The Journ

109, » 686, 858, 929

Botany, Notes, 102, 681, 764, 852

General Biology 173, 747

: 767

. 601

Geology. . .

Geology, Notes

Nature Study .

Zoölogy,

339, 411, sot, 602, 751, 845

Zoology, Notes

416, 504, 754

Rana v

PAGE

Notes on genitalia of Lymnza 665

Notes on recent fish literature . . gı

North American Araneida, u.

sis of families and genera « 293

North American Pintian yp.

| opsis of "Ed e 425

OCCURRENCE and origin of amber

in eastern United States . . . 137

Occurrence of Echinostomum spin-

ulosum rn D. pu. 0265

CGEcanthus fasciatus, Habits of 1

Ortmann, A. E. Zoögeographical

relations of South America 413

Ostracod, A new, from Nantucket 791

Oyster, Larva i spat of Canadian 41

PALAECHINOIDEA, Klem on

Parthenogenesis,

tificial

Pearl, R. Variation i in ray Bowers

of Rudbeckia . .

Peculiar variation of Tirebralalie

transversa

Penhallow, D. P. A fiten

study of the Salicaceæ .

. 754

Natural and ar-

lar cylinder of hybrid catalpas

Petrunkévitch, A. Natural and ar-

tificial parthenogenesis 5

Plant cell, Studies on 217, 449, eis. 695

Pomace fly, Reactions of, to light,

nn, and mechanical stimula-

tion . 157

Poste connections of RR vein

ofthe skate vo». MO

Publications vivid: : [I

AIA and eg Muscles of 891

vir, € d Ayla ander-

sonii in New Jersey (7

Rand, H. W. The skate lor sinis

in comparative mem injec-

tion methods QUE

—— and Ulrich, J. E Posterior

connections of lateral vein of the

skate u

Reactions of baee Ay to ; light,

gravity, and mechanical stimula-

ion = s I

INDEX.

PAGE

Reptilian lower jaw, Bones o

esponse, Angle a necp stems

show strongest geotropic

Restoration of the titanothere

Megacerops

Reviews:

A new North American Flora

Aldrich's Catalogue of North

American Diptera

Ames’ Studies in the Orta

Bailey’ s Plant- ER ‘

Baker’s Shells of Land mu

Waer 2504 2

Barron's Old Whaling Days

Bastian's Studies in Hetero-

genesis

Bergen's ER Notebook

Brandt’s Nordisches Plankton

Britton’s Manu

al ; 9

Carter's Nature Bak en

Common Thin . 60

RER s Bg RER

genetique

` Le Dantec's T aie de biologie

Driesch's Naturbegriffe und

Naturteile

“os -7

Duckworth’s ifarahan s

logy .

s New

Ferns and their Common

Allies .

Gardiner’s Fauna ind og

the Maldives

Controverses trans-

Natural History

Herrick’s Home Life of

wid Bra. . &, 2.

Hoffmann’s Guide to the Birds

of New England and New

York .

Hornaday's Adern Natural

History

RAE

land

iie s Cann:

. 419

851

173

- 502

. 340

: 339

847

Jacobi's Tiergeographie

Lloyd m Bigelow’s Teaching

of Biology

McMurrich’s

the Hum

Mathews’ oe Rokk of wild

Birds and their Music

Merrill’s Treatise on R

oc a

Development of

Bod

Mouillefert's Traité de sylvi-

culture vin tie

Overton's Naik e Study .

Peckhams’ Wasi Social iod

Solita

Pfeffer's Pflanzenphysiologe . s

lard's Traité d' histologie

wen Watchers of the

e F

f eost s Text back si Zoöl-

ogy .

Stone’s Timbers of Cometa

Townsend’s

County, Mase... u: 103

Trouessart’s Catalogus Mam-

ium, Supplement 603,

De Vries’ — and Varie-

ties

Ward’s Tess vol. 2

Wests’ British Dabir

Wests’ ritish Fresh-water

g re

Rhizopods, Fresh-water,

from

White Mountains o ew

Romeiser, T. H. Case of abnor-

al venous system in Necturus :

Rudbeckia, Variation in ray flow-

ers of

SALICACE&, A systematic study of

509,

Sedges and ee Fossil .

Shimer, H. W. Peculiar variation

of ipa transversa

PAGE

Birds of Essex .

797

* 345

Sir Charles Blagden, earliest of

Rhode Island ornithologists .

Skate for classes in erg

anatomy; injection met

Skate, Posterior connections of

Smith, B. G. Collection RR prep-

aration of zoölogical material

South America, re er

relations of

Sporozoa, titarea of

Stafford, J. Larva and spat of

Canadian oyster . . .

Studies on the plant cell

449, 555»

Synopses of North kai inver-

tebrates. XX. Families and

genera of Araneida AM ur

XI The Nemerteans.

Ft. a 5 354 € X79

Systematic study of the Salicacex

509,

TEREBRATALIA Zransversa, Pecul-

lar Variation OF 4. . a,

Transeau, E. N. Forest centers

of eastern America

INDEX. vil

AGE

875

PAGE

ULRICH, J. L. See Rand, H. W.,

and —

VARIATION in ray flowers of Rud-

beckia . 87

Variation of are trans-

rsa

Varisin, Moe i uu ees

Vascular cylinder of hybrid eatal-

pas, Anatomical changes in . . 113

Vidaus systemin Necturus, Abnors

NN ike ee L4 EXAM 2:908

West Indian whitebait, Habits of 331

Whitebait, Habits of West ver LM

Willcox, M. A. Biology of Acm

testudinalis Müller . . » 338

Worthington, J. Con tribution to

our i khovidlge of Myxinoids . 625

ZAPPEY, W. R. See Bangs. O.,

and ——.

en relations of South

America 413

Erratum.

In the article by F. C. Baker, pp. u

679, Figs. 5 and 9 should be trans-

posed.

| : y y *« t

; PE

. t 5 i 3

THE

AMERICAN NATURALIST.

Vor. XXXIX. January, 1905. No. 457.

THE HABITS OF THE STRIPED MEADOW

CRICKET (@CANTHUS FASCIATUS FITCH).

JOSEPH L. HANCOCK.

In uncultivated wastes the common horse-weed (Leptilon can-

adense L.) often takes possession of the soil and flourishes most

luxuriantly. Owing to its rapid growth, it not infrequently

overshadows the neighboring clover, wormwood, knotweed,

daisy fleabane, and other forms of plants which may happen

to live where its society conflicts. There are many interesting

features in the miniature forests of weeds, not the least of which

is the insect life they harbor. In the last of August the weed

first mentioned commonly attains a maximum height in sandy

soil of from four to six feet, and it is at this period that it seem-

ingly furnishes an ideal environment for the striped cricket

(Ecanthus fasciatus Fitch.!

My experience with this cricket (see Fig. 2), which is here

related, is principally drawn from observations made at Lakeside,

Michigan, during the month of August, the last day of Septem-

ber, and the first two days in October, 1904. Further studies

1 This cricket is commonly classed among the tree crickets, but it never or

rarely lives on trees.

2 THE AMERICAN NATURALIST. | [Vor. XXXIX.

of its habits were carried out on numerous live individuals which

I transported to my home in Chicago.

I have found this insect living singly, or from one to four

together, upon the horse-weed, the females predominating during

August. It is found more often on the main central stem, from

eighteen inches to two and a half feet from the top, attracted

there doubtless for the purpose of courtship and oviposition.

Here it exhibits exquisite protective resemblance. The body of

the insect is colored pale green, but the legs, antennae, maxillary

palpi, head, thorax, cerci, ovipositor, the ventral aspect of the

thorax and abdomen, are very dark, though the color is 5ome-

what variable. It is a delicate soft bodied insect, with excep-

tionally long antenne. One of its favorite habits is closely to

grasp the green main stem of its chosen plant with its body

resting upside down. When disturbed, its first impulse usually

is to jump to the ground, where its black legs, blending with

the background of earth, are invisible, while the top of the body

being green, now appears from above like a small blade of grass.

If the insect is again molested while on the ground, it jumps

quickly here and there in a spasmodic manner, then catching

hold of some herbage climbs upon it. After waiting sufficiently

long for danger to pass, the cricket eventually springs from one

small plant to another until it again finds the main stem of the

horse-weed. It then climbs up to take a position similar to that

which it formerly occupied. One may often find it at rest, with

its legs extended nearly straight out behind the body ; or it may

appear on the flowers feeding. After a dry spell of weather in

August, the older weeds, often selected as a residence by the

crickets, present a series of dead brownish leaves below, that

extend from the ground a third or more the length of the plants

upwards. Because of the existence of these dead leaves and

shadows, the darker parts as well as the light coloring on these

insects serve as excellent protection. Moreover, as they rest on

the main stem, among the maze of leaves they enjoy complete

immunity from their grosser enemies. Later in the season the

habits undergo some modification incident to the change in the

vegetation. For instance, on September thirtieth, I visited the

horse-weed patch which furnished the theme of the above narra-

No. 457.] ECANTHUS FASCIATUS. 3

tion, to find that many of the weeds, while still standing, had

turned brown and were dead. There were very few crickets to

be found at the point where they had been so common before.

After a long search a number were located in quarters some-

what different from those in which I had previously found them.

They had taken up positions near the ground. To enumerate, I

discovered one female hiding ten inches above the earth, within

a folded dead leaf of a ground cherry. Close by was a male on

a green leaf of the same plant. Immediately following these

observations, I found two more males and a female on the light,

yellowish green leaves of another of these plants. Similarly,

a pair which were almost invisible. were crouched among the

leaves and seed receptacles of a Potentilla. On October first,

among some wild blackberry bushes, I noted a number of these

crickets of both sexes walking about on the upper surface

of the leaves. The slightest motion on my part caused them

to seek safety by darting around the side margins of the leaves,

disappearing underneath, or they would jump below. Here I

found two males near: together clinging on upside down, each

hiding within a curled leaflet of the blackberry. A stem of one

of these plants which I found here, shown in the reproduced

photograph (Fig. 1, a), shows ten punctures made by the oviposi-

tor of fasciatus. The scarring of the plant in this way did not

appreciably affect the health of the branch, the leaves of which

were fresh and green. The same day I located a number of

rather large plants of the golden-rod, the stems of which were

used by this oecanthid for depositing her eggs. The points

selected for this purpose were often situated half way down the

main stem. Here the darkened scar areas can be recognized

on the green stems where a number. may be found lying in close

proximity. The holes which are near together take the form

of vertical continuous lines of varying length, or they appear

dotting the surface irregularly, as shown* in Figure 1, 4 and c.

A broken longitudinal section of the golden-rod at the scarred

places will show the eggs disposed in the manner represented

in Figure r, d. Or sometimes the eggs will be found missing,

and instead of them there will be encountered a white larva

which destroys the eggs. This grub tunnels through the cen-

tral pith, feeding on it and leaving the stems hollow. —

THE AMERICAN NATURALIST. [VoL. XXXIX.

"UM

a "^ : c

name nm

Fic. 1.— Stems of the nn a, the horse-weed, 4, and the golden-rod, c and d, which

ave been stripped of their leaves to clearly show the holes made by (Zcanthus fasciatus

during oviposition p portion of the stem d has been removed longitudinally to show the

eggs in situ. Photographed by the author.

No. 457] CECANTHUS FASCIATUS. | 5

The Call Notes. — At 11.30 on the morning of September

thirtieth, as the sun became overcast by clouds, I was treated to

a pretty serenade by a-host of males, which being hidden in a

dense thicket of weeds gave out an exquisite example of their

orchestration. Beyond this spot, in the open field planted with

clover, but grown over with a mixed wild herbage, which in-

cluded more or less scattering of the horse-weed, I heard the

shrilling. After a little experience, one is led quite easily into

‘the presence of these: crickets by their song, as the following

2. — Ecanthus fasciatus. The female is shown on the male's back in the attitude of de-

“vowing the plasmatic secretion within the thoracic gland located at the central part of the

me um ni ten ale. Protographed by the anter, from living posed individuals, which

x 1$

incident will prove. At 2.30 in the afternoon of October first,

during the bright warm sunlight, I heard what seemed to be a

chorus of fasczatus emanating from a source quite a distance off.

From the open field where I stood, I gradually traced the trills

to a corner of an adjoining unmowed field where the crickets

appeared in abundance in a small wild blackberry patch. On

near approach some of the songs ceased, but they soon com-

menced again when I stood perfectly quiet.

6 THE AMERICAN NATURALIST. (VoL. XXXIX.

After nightfall, as well as in daytime, the high-pitched shrill

notes of this cecanthid are uttered at irregular intervals, sound-

ing not unlike the croaking of a frog or of a sparrow's notes

when heard at a distance. They are not so monotonous as

those of the large familiar black gryllid, or so resonant as the

notes of the mole cricket. The concerts accompanying their

little social gatherings may well be placed among the choicest

of insect orchestrations.

Method of Alluring the Female during Courtship. — The male

of this cecanthid possesses a remarkable mechanism for alluring

the female during the period of courtship. He not only uses

the pretty modified tegmina as an artifice in attracting her, but

he also brings into operation a most peculiar thoracic device

about to be described. In order to attract the female, the male,

having approached within her sight, commences his advances by

elevating his transparent tegmina to a nearly vertical position

or right angle. Then separating them so that their surfaces

rub together in and out, he produces a high-pitched shrilling for

the female's benefit. She, in turn, being readily attracted by

these notes moves towards him, and climbing on his back goes

sufficiently far forward that her attention is further drawn to

the little odd-shaped glandular fossa on the back of the thorax

between the wings. Here she at once inserts her mouth to

find a delicious potion secreted for her special needs, and which

she devours ravenously, as depicted in Figure 2. The male in

the meantime may or may not cease his singing, but while she

is availing herself of the curious plasmatic drink, his tegmina

are continually elevated, and his wings, which are folded at his

sides, undergo a slight rhythmical motion in and out, lasting

during the five to ten minutes she is usually content to stay.

When she moves away he backs around towards her, again ele-

vating his tegmina and repeating his song. Similarly affected

by his overtures, and remembering the reward of sweets awaiting

her return, she again mounts his body and proceeds to partake

from his loving cup. These executions are repeated several

times as a preliminary to the sexual act. Now the female is

prepared by some subtile influence exerted by the male and she

stays near by ready to again answer to his allurements. He

No. 457.) CECANTHUS FASCIATUS., 7

finally raises his tegmina in full display, and singing again to her

she immediately reciprocates by mounting his body, but instead

of indulging in his loving cup this time, she curves the end of

her abdomen slightly downward, while at the same time he

backs up and raising the end of the abdomen, conjugation is

effected. The latter process lasts but a few seconds. After

the sexual act, the female may be seen curving the end of her

abdomen underneath forward, in order that she may clean the

ovipositor with her mouth and include the genitalia in this toilet.

I have frequently observed the males in active combat over

the possession of the female. As a result of these struggles,

later on in the season, the males become decidedly dilapidated

in appearance, the legs and wings having suffered more or less

destruction as the result of the many contests for supremacy.

The Alluring Gland. — The function of the gland (Fig. 3), as

above intimated, is solely for the purpose of alluring the female

and it may be classed as a secondary sexual organ. It may be

described as a moderately deep fossa, situated in the center of

the metanotum of the thorax. It is bounded laterally by con-

vex, rather obtusely rounded sides which converge and coalesce

in front. Here anteriorly the border is flattened or depressed.

On either side before the middle the lateral borders are strongly

tumose, being provided with numerous sensitive hairs, the lateral

borders behind the middle being continued into narrow convex

ridges. The inner margins of the lateral borders are trisinu-

ately excavated. Behind the gland lies the anterior concave

border of the scutellum. Within the gland, occupying a point

opposite the middle sinuation on either side (Fig. 3, c), is a flat

brush of glandular hairs which project into the cavity obliquely.

Just below, on either side, is another smaller brush (Fig. 3, 4)

composed of similar hairs which are directed inwards. The pos-

terior half of the floor of the cavity is darker in color, being chi-

tinized, and thus showing a line of demarcation separating it

from the forward translucent portion. The posterior floor is,

moreover, divided by a transverse sinuous ridge, and the inner

third here behind (Fig. 3, 7) is clothed with hairs.

An experiment on live crickets demonstrated that when the

hairs on the surface of the swollen anterior lateral borders (Fig.

8 THE AMERICAN NATURALIST. . (Vor. XXXIX.

3, à) were stimulated by touching them with the point of a small

artist's brush, or head of an insect pin, it gave rise to a respon-

sive movement of the wing of the opposite side of the body.

The same stimulus applied to both sides at the same time

caused both wings to move or jerk simultaneously.

From these simple experiments I am led to infer that the

motions of the wings witnessed during the sexual performances

previously described are automatic in nature. They are caused

Drawn by the author.

by the female palpi touching the sensitive hairs above alluded.

to, during the time she is drinking.

When examining the male, one may often find, when raising

the tegmina, a small plasmatic yellow droplet of the glandular

secretion on the under side of the lower tegmina, opposite the

position of the gland. This is an excessive fluid secreted from

the glandular hairs. The gland fossa is often found filled

No. 457] CECANTHUS FASCIATUS. 9

with the fluid, which seems to be partially soluble in water.

When the gland becomes dried out, the evaporation of moisture

causes the hairs, which are normally arranged in the flat rows

before mentioned, to come together forming acute pencils.

These pencils then take on the appearance of teeth, quite mis-

leading to the casual observer. ‘A small drop of water carefully

placed in the cavity, while under the microscope, soon dispels

this illusion by causing the hairs to spread out in the same way

that a hair brush shows its individual hairs after a dried, sticky

substance has been soaked out of it. My illustration (Fig. 3)

presents a view of the entire gland after being treated with a

drop of water.

From the foregoing statements regarding the sexual habits

and the connection of this gland therewith, it may be of interest

to note that the suggestion made by Blatchley (Orthoptera of

Indiana, p. 452), that during the mating of this species the

female removes the semen from the glands whose openings are

intimated to be beneath the tegmina of the male, and that she

then fertilizes her ova with the secretion there obtained is, as a

matter of fact, wholly erroneous. There is also a doubt regard-

ing the correctness of certain notes of Harrington on the habits

of the snowy tree cricket, which has a bearing on this subject.

Howard quotes Harrington as mentioning the following : * An

interesting feature of its concerts is one of which I have not

been able to find any mention in books accessible. While the

male is energetically shuffling together his wings raised almost

vertically, the female may be seen with her head applied to the

base of the wings, evidently eager to get the full benefit of every

note produced." (/nsect Book, p. 344.) My studies of the

thoracic gland of the snowy cricket show this structure to be

similar to that of the striped species, fasciatus ; consequently,

is it not possible that Harrington witnessed the female in the

act of drinking from the gland without realizing the entire mis-

sion of her attitude? Blatchley gives an interesting account of

the male wooing the female in the work before cited. He found

them on the heads of the sunflower.

Besides the alluring gland above referred to, this cecanthid

has a singular eversible, sacculated structure situated at the dor-

Io THE AMERICAN NATURALIST. [Vor. XXXIX.

sum of the abdomen, in the fold between the third and fourth

tergites. In handling the living male, and raising the tegmina

with one’s fingers to an angle of forty-five degrees or more, the

gland may be detected. It does not protrude except during the

first moments of excitement of capture when its folds are thrust

out. This would indicate that the structure is a repugnatorial

organ, though this is conjectural, there being no odor given off

from it. A similar gland occurring in a like situation, on the

dorsal aspect of the allied snowy cricket, C. niveus, gives to the

insect, when likewise excited, a faint odor not unlike some

flower.

The Method of Oviposition. — On October first, I examined

a large number of the horse-weed and golden-rod a-field, which

showed the scars where the crickets had oviposited. The fact

was developed that the eggs of this species were always depos-

ited on the sunny south exposure of the main stem of the plants.

This is obviously an advantage in furnishing the necessary heat

in hatching the eggs, and to the delicate young when they first

emerge. In Figure ı the serial subfigures represent the stems

of the blackberry, horse-weed, and golden-rod, all shorn of leaves,

to demonstrate the scars or holes, as well as the eggs 7 situ.

I witnessed the act of oviposition for the first time on the after-

noon of September 12, and thereafter observed it on a number

of occasions. In brief the process is as follows: the female

coming to a suitable spot on the stem, she prepares it by biting

it with her jaws, spending scarcely a minute in doing so. Then,

moving her ovipositor under her body at nearly a right angle,

she places the tip into this superficial abrasion and immediately

proceeds to drill a hole. The drilling is accomplished by rotat-

ing the ovipositor while keeping the end, which is provided with

a dentate rasp, firmly pressed against the stem. The abdomen,

which she turns from side to side, takes an active part in this

procedure, acting as upon a pivot, and at times covering about

forty degrees in these movements. The ovipositor is soon

passed through the tough external covering and finally pene-

trating deeper and deeper into the pith. In the beginning the

course of the hole takes a right angle, but as she proceeds its

direction is changed, taking a curved inclination backwards, as

No. 457.] CECANTHUS FASCIA TUS, TI

. depicted in Figure 1, d. When the female has bored into the pith

as far as the ovipositor can go, she then discharges the slightly

curved egg very slowly. Then after withdrawing the organ, she

finishes the process by chewing the stem at the point of entrance

as she did in the beginning of the operation. The anterior,

whitish tipped pole of the egg usually lies within a millimeter of

the opening. This is shown in the specimen of golden-rod (Fig.

1, d) laid open for inspection. Some of the eggs here show the

whitish micropilar extremity quite clearly. I did not see the

female use the same hole for the deposition of more than one

egg.

One night at 7.30, under artificial light, I observed a female

boring a hole, but when she arrived at the stage where she was

about to oviposit, she suddenly pulled out her ovipositor without

having accomplished her purpose. It was then disclosed that

the egg had stuck in its passage, for the next moment she

brought the ovipositor forward underneath her abdomen and,

spreading the blades apart, she extracted the egg with her

mouth and rapidly ate it. This latter act does not seem to

be unusual among the orthoptera under like conditions, as I

have witnessed it in several widely different species. She then

went over her ovipositor carefully cleaning it with her mouth.

Commencing at the tip, she spent several minutes passing from

the point along its entire length, giving great attention to the

preparation of the base and genitalia. This latter performance

seemed to have been done with a view to forestall further acci-

dents, for almost immediately afterwards she started to again

oviposit, and this time, as well as thereafter, had no difficulty

in placing her eggs successfully.

THE EMBRYO OF THE ANGIOSPERMS.

& HAROLD L. LYON.

THE angiosperms are the dominant plants of present floras,

and were the first to be thoroughly studied by botanists. The

seed habit, providing a definite period for embryonic develop-

ment, and the large embryos, often obtaining as a result, made

the embryology of the angiosperms especially easy and attrac-

tive. Simple lenses and primitive technique served for the

study of these embryos, and a knowledge of them was well

advanced before better instruments and better methods were

employed to elucidate the embryogeny of lower forms.

The angiospermous embryo was early hit upon as furnishing

fundamental data for systematic classification. This quickly

brought such embryos into prominence in botanical literature,

and controversies immediately arose as to the morphological

values and homologies of the embryonic members. While a

creed, serviceable and satisfactory to the systematists, was soon

evolved, the chief questions in morphology have continued to

the present day quite unanswered. The aspect of the problem

has changed from time to time with increasing. knowledge and

if we would now attempt a solution we must strive to answer

the three following questions.

Are the angiosperms monophyletic ?

Are cotyledons true leaves ?

To what structure, if any, in the monocotylous embryo are

the cotyledons of a dicotylous embryo equivalent ?

An answer to the last question is, of course, the one most

generally desired ; but to discuss this question one must take

some position as to the phylogeny of the classes of angiosperms

and to the morphological value of cotyledons.

ARE THE ANGIOSPERMS MONOPHYLETIC ?

It had been so generally conceded that the angiosperms have

a common ancestry that in a former paper the writer (: 02) dis-

14 THE AMERICAN NATURALIST. (VoL. XXXIX.

missed this question with the following brief statement, ** That

the Monocotyledons and Dicotyledons have a common ancestry

there is no reason to doubt. One would hardly suppose that

the similar complicated cytological phenomena of embryo-sac

development and endosperm formation were simply parallelisms

in two groups of different phylogenetic origin.” Later, how-

ever, Balfour (:o1) in discussing the phylogeny of the angio-

sperms, said, * Were I to maintain an opinion it would be that

the two classes have arisen on separate lines of descent. The

embryo characters as well as those of the epicotyl can, I think,

be shown to be fundamentally different and to afford no basis

for an assumed phyletic connection."

Since Balfour, Coulter and Chamberlain (:03) have written

on the same subject as follows: * The first phase of the prob-

lem has to do with the common or independent origin of the

Monocotyledons and Dicotyledons. It has been assumed gen-

erally that the two groups are monophyletic. The chief argu-

ment, and in fact the only morphological one for the monophyletic

theory, lies in the great uniformity of the peculiar development

of both male and female gametophytes. It is argued that the

independent origin of such exact details of development and

structure is inconceivable, and this argument has been reén-

forced recently by the discovery in both groups of the peculiar

phenomenon called. ‘double fertilization. The argument is cer-

tainly a very strong one, and yet there are rebutting proposi-

tions. Even such similarity in structure may be the natural

outcome of the changes that resulted in the evolution of seeds,

and these are now generally believed to have appeared in inde-

pendent lines. Again, the fundamental differences in the devel-

opment of the embryos of the two groups are hard to reconcile

upon the theory of monophyletic origin. Add to this the funda-

mental differences in the structure of the stem and in the

character of its vascular bundles, and the derivation of one group

from the other seems more inconceivabie than the derivation of

the Dicotyledons from the Gymnosperms. Still another argu- |

ment against the monophyletic theory is furnished by the histori-

cal testimony. The Proangiosperms of the Lower Cretaceous,

so far as known, appeared associated with undoubted Mono-

No. 457.] EMBRYO OF THE ANGIOSPERMS. I5

cotyledons, and merged gradually into recognizable Dicotyledons.

The emerging of Dicotyledons from this vague group either

indicates that Monocotyledons and Dicotyledons originated inde-

pendently or that the Proangiosperms were transition forms

between Monocotyledons and Dicotyledons. This latter alter-

native is in turn inconceivable, especially since the most primi-

tive Dicotyledons are recognized to be even more primitive than

any of the Monocotyledons.....In our judgment the evidence

is strongly in favor of the independent origin of the two groups,

which have attained practically the same advancement in‘the

essential morphological structures, but are very diverse in their

more superficial features. Their great distinctness now indi-

cates either that they were always distinct or that they originated

from forms that were really Proangiosperms and neither Mono-

cotyledons nor Dicotyledons.”

Few morphologists will agree with the statement that the only

morphological argument in favor of the monophyletic theory is

to be derived from the similarity in embryo and endosperm

development. There is in both classes a remarkable conformity

to one common plan in all phases of their organogeny ; not only

in the embryo-sac, but in the development of floral structures,

androecia, gynoecia, ovules, seeds and fruits. While many simi-

larities in plant structures have undoubtedly resulted through

parallel development, is it not carrying the idea to an unwar-

ranted extreme when it is attempted to explain all the exact

details of development, which obtain alike in both classes of

Angiosperms, as simply parallelisms, especially since no tangible

evidence is brought forward to justify it ?

If the fundamental differences in embryogeny are to be

delineated by the exceptionally perfected embryos of Alisma and

Bursa, as is so generally stated, they might be considered hard

to reconcile. If on the other hand they are to be determined

by a comprehensive comparison of the various types of embryos.

to be found in the two classes, the real difficulty is not, how to

reconcile these differences, but how to locate them. An exam-

ination of recent embryological work ! will show that no funda-

1Sterckx ('99), Lyon (:01), Cook (: 02), Schmid (: 02), Sargant (:02, : 03, : 04),

Schaffner (:04), York (:04).

16 THE AMERICAN NATURALIST. (Vor. XXXIX,

mental differences can be distinguished. Coulter and Chamber-

lain themselves in a previous chapter of the same work, write,

“ The distinction between Monocotyledons and Dicotyledons is

not always clear in the embryo."

Should fundamental differences in the structure of the stem

and its vascular bundles be pointed out, this “ rebutting propost-

tion” might prove a serious one. It is certain, however, that

such an opinion can carry little weight when opposed to the

conclusions of careful investigators supported by their researches.

And almost without an exception, students! who have actually

worked on the stem anatomy of the angiosperms with a view to

determining their phylogeny, concur in the opinion that here

also the evidence is for and not against a monophyletic origin.

There is a characteristic type of stem and bundle structure

prevalent in each class it is true, but in certain plants of both

they so closely approximate a common type that no hard and

fast line can be drawn between the classes on this basis. That

both types have been evolved within the angiosperms from one

fundamental pattern is amply demonstrated by existing plants as

the above mentioned students have shown. Coulter and Cham-

berlain (:03) would place the Nymphsacex among the dicoty-

ledons because of their embryo-characters ; but no one has

ever been able to show that the stem structure of the Nymphe-

aceze is other than essentially that characteristic of monocotyle-

dons. In placing the Nymphzacez as they do, they themselves

admit that there are no differences in stem structure between

the plants of the two classes which are fundamental.

As to the historical testimony which is to be derived from

palzeobotany, Seward (: 03) has shown that, in the extent of our

present knowledge, it is to be considered of questionable value.

While giving due consideration to these adverse opinions ;

admitting that an independent origin of the monocotyledons and

dicotyledons is not inconceivable, and that all their common

morphological, structural and cytological peculiarities might be

simply parallelisms ; still we are justified in accepting the

strongly fortified conclusion, borne out by all obtainable evi-

* Queva ('99), Jeffrey (: 00, :03), Worsdell (: 02), Sargant (: 03).

No. 457.] EMBRYO OF THE ANGIOSPERMS. I7

dence, that the angiosperms. are monophyletic ; that their most

recent common ancestors were Angiosperms.

ARE COTYLEDONS TRUE LEAVES?

The oldest and at all times the favorite interpretation of coty-

ledons is that they are arrested or metamorphosed foliage leaves.

The antiquity of this view as well as the basis on which it was

founded is well set forth in the following quotation from Sachs’

History of Botany: “We see that Cesalpino uses the same

word * folium" without distinction for calyx, corolla and ordinary

leaves ; just as he and Malpighi a hundred years later unhesitat-

ingly regarded the cotyledons as metamorphosed leaves. In

fact the envelopes of the flower and the cotyledons approach so

nearly to the character of leaves that every unprejudiced eye

must instinctively perceive the resemblance.”

From time to time various authors, while accepting the foliar

theory of cotyledons in its general application, have concluded

that the analogous structures in certain plants are not true coty-

ledons but organs of a different morphological value. The

scutellum of the grasses, which is now commonly considered a

cotyledon, has been variously interpreted.? Richard (’11) dis-

tinguished as * Embryons macropodes’ the embryos of the

grasses, Nelumbo, Ruppia, Hydrocharis and Zostera. The

scutellum of the grass embryo and the cotyledonary lobes of the

embryo of Nelumbo he considered homologous to the massive,

macropodous portions (l’'hypoblaste) of the embryos of Ruppia,

Zostera and Hydrocharis. This hypoblast he interpreted as a

lateral outgrowth or expansion of the radicle. Schaffner (:04)

compares the embryos of the Nymphzacez with those of Rup-

pia, Zostera and Halophila. He reiterates Richards conclusions

concerning the homology of the cotyledonary lobes with the

macropodous body which he terms a hypocotyledonary expansion.

Nageli (78), however, early ventured the opinion that “ Der

Embryo der Gefásskryptogamen und der Phanerogamen ist kein

Caulom sondern ein Thallom, wie das Mooseporangiun, aus dem

! English translation 1890, p.

2 Vide Bruns ('92) and nds (:00).

18 THE AMERICAN NATURALIST. (VoL. XXXIX.

er phylogenetisch hervorgegangen ist; die Samenlappen sind

keine Phyllome, sondern Thallomlappen. An dem Embryo tritt

als neue Bildung der Stengel auf."

In a lecture delivered at the Minnesota Seaside Station in

June, 1901, and since published in the Year Book of the station,

the writer suggested that cotyledons are not arrested leaves but

are primarily haustorial organs, originating phylogenetically as

the nursing-foot in the Bryophyta and persisting throughout the

higher plants.

Balfour, in his presidential address to the Botanical section of

the British Association, September meeting, 1901, said, ** We

ought, I think, to look upon the embryo of the angiosperms as

a protocorm of embryonic tissue adapted to a seed life. Under

the influence of its heterotropic nutrition and seed environment.

it may develop organs not represented in the adult plant, as we

see in, for instance, the embryonal intra-ovular and extra-ovular

haustoria it often possesses. There is no reason to assume that

there must be homologies between the protocorm and the adult

outside an axial part with its polarity. There may be homolo-

gous organs. But neither in ontogeny nor in phylogeny is there

sufficient evidence to show that the parts of the embryo are a

reduction of those of the adult. .... I cannot pursue the subject

here nor discuss the view of the cotyledons as either ancestral

leaf-forms or arrested epicotylar leaves. The analogies with

existing Pteridophytes that are cited are not pertinent, for there

is no evidence that angiosperms have that ancestry, or indeed

that their phylogeny was through forms with free embryos.

Nor is the fact of resemblance between cotyledons and epicoty-

lar leaves and the existence of transitions between them con-

vincing. That the cotyledons, primarily suctorial organs, should

change their function and become leaf-like under the new condi-

tions after germination is no more peculiar than that the hypo-

cotyl should take the form of an epicotylar internode from which

it is intrinsically different as the frequent development upon it

of hypocotylar buds throughout its extent shows.”

While each of the above authors expresses a distinct interpre-

tation quite at variance with those offered by the others, still all x

declare alike on our present point of discussion, that cotyledons.

are not morphologically foliage-leaves.

No. 457.] EMBRYO OF THE ANGIOSPERMS. 19

Ramaley (:02), who for the past ten years has been working

on the comparative anatomy of dicotyledonous seedlings, ex-

presses his opinion on this subject in the following statement :

“] think also that the theory of the above named writer [Pres-

ton, : 02] to account for the lobing of cotyledons is of no great

value. He suggests that the lobing of the foliage leaf is

‘thrown back’ upon the cotyledon. This assumes firstly that

‘throwing back ’ can actually occur, while as a matter of fact it

yet remains to be proven; and secondly, that the cotyledons

are homologous with leaves, something which also remains un-

proven. The suggestion! concerning the morphology of the

cotyledon made at the recent Chicago meeting of botanists of

the central states seems more reasonable than the one which

would consider the cotyledons as really a leat."

Many other writers have expressed dissatisfaction with the

foliar theory without taking a decided stand against it. Klebs

(83) in his excellent treatise on germination pronounces the

subject an enigma, while Lubbock (92), who has undoubtedly

made more extensive observations upon seedlings than any

other one man, writes: * No one who has ever looked at young

plants can have failed to be struck by the contrast they afford

to the older specimens belonging to the same species. This

arises partly from differences in the leaves, partly from the con-

trast which the cotyledons, or seed-leaves, afford, not only to the

final leaves, but even to those by which they are immediately

followed. This contrast between the cotyledons and true leaves

is so great that one might almost be pardoned for asking

whether they can be brought in correlation. So far, indeed,

are the cotyledons from agreeing with the forms of the leaves,

. that the difficulty is to find any which have been clearly influ-

enced by them. One species of Ipomoea (I. Pes-caprae) has

both cotyledons and leaves, as the name denotes, somewhat like

the foot of a goat; but the leaves vary considerably, and it is

probable that the resemblance may be accidental. A clear case

is, however, afforded by the Onagrariez, where in CEnothera

and some allied genera the form of the mature cotyledons is

! Lyon (:02).

20 THE AMERICAN NATURALIST. (VoL. XXXIX.

evidently related to the leaves. Even here, however, the resem-

blance is confined to a basal portion of the cotyledon which

makes its appearance subsequent to germination, and no trace

of it is shown in the cotyledons themselves when they first

appear."

We can readily see from Lubbock's work that a morphological

leaf-value has been ascribed to cotyledons solely on their resem-

blance to foliage leaves, a resemblance which is acquired after

germination when the cotyledons are functioning as photosyn-

thetic areas. Then they are only in general leaf-like, for if any

cotyledons be compared with the foliage leaves of the same

plant they are found to differ from these, usually to a marked

degree in form, texture and venation. The resemblance is never

more than such as might be wholly induced by the assumption

of the vegetative function, for the cotyledons become function-

ally similar structures in the same environment as the leaves.

Natural forces seem to call forth a remarkably constant type of

foliar organ in all those plants where any extent of tissue is

specialized for this purpose no matter what the morphological

value of the tissue may be. The gametophytes of some mosses

develop leaves which are quite similar to the simpler leaves

produced by the sporophytes of many pteridophytes and phan-

erogams. Phyllodes and Phylloclades are well known cases

where the assumption of the function has, in many instances,

been followed by the assumption of the form of leaves.

Ramaley has undertaken a study of the comparative anat-

omy of cotyledons and leaves. In his paper (:03) on the coty-

ledons and leaves of the Papilionacez, he writes: “In the

plants. examined, all of which have cotyledons which function

for a tme as leaves, the anatomical structure is strikingly differ-

ent in cotyledons and leaves... The stalk of the cotyledon

when present has a structure different from that of the leaf-

Ra Again (:04) he writes: “In the Ranunculacez and

Cruciferze studied there is not as great a difference in structure

between cotyledons and leaves as was seen in the Papilionacez.

ws The stalks of the cotyledon and leaf are quite different in

anatomical structure... . . In these families as in the Papilionaceze

there seems to be no relation in external form between the coty-

ledon and leaf." : |

No. 457.] EMBRYO OF THE ANGIOSPERMS. 21

The ontogenetic origin of the cotyledons would seem to deny

the foliar theory since they do not arise as exogenous lateral

outgrowths upon the growing point of the stem as do all later

foliar structures. Their appearance always precedes the differ-

entiation of the stem-apex.

Thus it appears that the foliar theory is supported only by

the fact that in some plants the cotyledons are borne on a stem

and are green, and may acquire a form resembling a leaf. It

seems certain that any “unprejudiced " observer must at once

admit that these are but superficial analogies ; quite insufficient

evidence to warrant the conclusions so universally based upon

them.

To WHAT STRUCTURE, IF ANY, IN THE MONOCOTYLOUS

EMBRYO ARE THE COTYLEDONS OF A Dicorvrous

EMBRYO EQUIVALENT?

Early embryologists considered the cotyledons of all angio-

sperms (with the exceptions already noted) to be structures of

the same category, morphologically as well as physiologically,

and their conclusions have been accepted by botanists in general.

Balfour (: o1), however, states that, * This terminal cotyledon

in the Monocotyledons is not a leaf nor the homologue of the

lateral cotyledons in the Dicotyledons."

In this opinion he is again supported by Coulter and Cham-

berlain (:03): * The current opinion regards it [the cotyledon]

as a modified foliage leaf, and this is borne out in the majority

of Dicotyledons by the assumption of the foliage function. The

terminal cotyledon of Monocotyledons, however, seems to belong

to a different category, and to hold no relation to a foliage leaf

or to a foliar member of any description." To discover evidence

which will in general prove the homology of the cotyledons, one

has but to consult the recent works of Sterckx (’99), Lyon (:01),

Cook (:02), Schmid (:02), Sargant (:02, :03, :04), Schaffner

(:04) and York (:04). Just as the observations of the above

mentioned investigators dispel all idea of such fundamental dif-

ferences in the embryos as would indicate two types of different

phylogenetic origin, so also do they show clearly that the coty-

22 THE AMERICAN NATURALIST. (VoL. XXXIX.

ledons of the angiosperms are morphologically of one category.

In 1809 Poiteau published the theory that the epiblast of cer-

tain grasses represents a vestigial cotyledon thus indicating a

dicotyledonous origin for these plants. This hypothesis has won

many adherents and but recently Van Tieghem ('98) has, on the

strength of it, placed the Grasses with the Nymphzeaceze under

a third class of angiosperms which he calls Liorhiza dicotyledons.

Van Tieghem's classification has been adequately dealt with by

Balfour (:01, :02) and needs no further attention from us at'

this time. Poiteau’s idea of the reduction of one cotyledon was

employed by Henslow (93) to explain the origin of the mono-

cotylous condition throughout the Monocotyledons.

Agardh (29-32) also accepted Poiteau's interpretation of the

grass-embryo but considered the Graminex the only true mono-

cotyledons. The’ Naiadex, Palmz, Aroidez, Lilieze and Scita-

minez, and probably other families of monocotyledons, he

classed as syncotyledones, considering the terminal structure of

their embryos to represent two cotyledons which had become

fused into a single member.

In a previous paper, the writer (:02) also concluded that the

cotyledon of a monocotyledon was equivalent to both of the coty-

ledons of a dicotyledon, but that the monocotylous condition

was the more primitive and that from this the dicotylous condi-

tion had arisen through a bifurcation of the originally single

cotyledon. The morphological value ascribed to the cotyledon

led primarily to this conclusion which was further strengthened

by embryological studies in the Nymphzacez.

i S a series of admirable papers, Miss Sargant (: 02, :03, :04)

as brought together much evidence, of which her own research

work has furnished a very important part, showing that the

cotyledon of a monocotylous embryo is equivalent to both of the

Bes of the dicotylous embryo. Add to this the evidence

fom the Ny niphacee embodied in the recent works of Lyon

Schaffner (: 04), and York (104) and the con-

i In considering the phylogeny

view suggested by Aga] ae e BREUER er

bien deed: y poo that the monocotylous condition has

rıved trom the dicotylous condition through the fusion of

No. 457.] EMBRYO OF THE ANGIOSPERMS. 23

two cotyledons into a single member. Thus while the relative

value of the cotyledons in the two classes needs no further dis-

cussion at this time, we have yet to choose between the hypoth- -

esis elaborated by Miss Sargant and the one suggested by the

writer.

It is obvious that the anatomical and morphological evidence

collected by Miss Sargant can as readily be interpreted in sup-

port of the writer's hypothesis as the one brought forward by

herself. It can quite as well be interpreted as showing a transi-

tion from the monocotylous to the dicotylous condition by a

bifurcation of the cotyledon, as demonstrating a reduction from

the dicotylous to the monocotylous condition through a fusion of

two cotyledons. It can be read forward as well as backward.

Progression in evolution is quite as plausible as retrogression,

yet Miss Sargant hopes to convince her readers with the fol-

lowing unique argument: “To conceive of steps by which two

separate cotyledons should gradually unite is easier than to

imagine a single cotyledon splitting into two similar members as

suggested by Mr. H. L. Lyon."

While Miss Sargant is able to cite some thirty dicotyledonous

seedlings as having their cotyledons partially or completely

united into a single member, one might easily mention a hundred

dicotyledonous seedlings having their cotyledons deeply emargi-

nate, bifid or even bipartite. Then cotyledons deeply three-

lobed, four-lobed, and five-lobed are not unknown. In various

species of Acer, seedlings with three and four distinct cotyledons

are of frequent occurrence. Pittosporum crassifolium produces

three or four cotyledons quite as often as two, while Auytsia

floribunda habitually produces embryos with three or four coty-

ledons. Would the writer propound an inconceivable hypothesis

were he to suggest that in these dicotyledons the variously lobed

and polycotyledonous conditiogs had arisen through a splitting of

cotyledons ; or must he adopt that *easier" line of reasoning

and maintain that the polycotyledonous condition is the more

primitive, and that the dicotyledonous condition has been arrived

at through a reduction by the gradual union of the many mem-

bers into two? All morphologists will affirm that this lobing of

the cotyledons has resulted through adaptation to the various

24 THE AMERICAN NATURALIST. (VoL. XXXIX.

conditions imposed by the seeds. Might not these same causes,

whose effect on two cotyledons is so often apparent, have pri-

marily induced the division of a single cotyledon into two? In

considering divided cotyledons, Lubbock ('92), concludes that

the bifurcation of the cotyledons in such plants as Eschscholtzia

and Schizopetalon are adaptations whereby the cotyledons are

better able to free themselves from the seed. If for this pur-

pose four cotyledons are superior to two, in what far greater

proportion are two cotyledons superior to one?

Although its evidence can never be taken as absolute, still we

are justified in placing some value on recapitulatory development.

If the monocotylous condition arose through the union of two

cotyledons we might reasonably expect to find, in our transition-

types, that two distinct cotyledon-primordia would first appear,

and conjoint development occur later. Such a sequence we

actually find in the development of gamophyllous perianths.

But in all the anomalous forms cited by Miss Sargant, of which

the embryogeny has been studied, a single primordium first

appears which, if the cotyledon is to become lobed at all, later

bifurcates.

In her first paper on this subject, Miss Sargant (: 02) attrib-

uted the reduction of the cotyledons to their specialization as a

sucking organ. Of the monocotyledons, she writes, *I have

regarded them for some time as specialized forms of an ancestor

with two seed-leaves. The complete union of the cotyledons

may very possibly be due to their common specilization as a

sucking organ. It is true that all cotyledons begin life by

absorbing nourishment from a food-body within the seed, but in

dicotyledonous seedlings they commonly lay aside that function

at an early period, even though they may never become assimi-

lating organs. Among Monocotyledons on the contrary, the

apex of the cotyledon often remains within the endosperm

throughout the existence of both, a period which covers years in

palms and some other plants. Such a habit as this would natur-

ally lead in course of time to the fusion of the cotyledons within

the seed." This hypothesis would seem to maintain that the

specialization in seeds has been from the exalbuminous towards

the albuminous condition. This supposition however meets

No. 457.] EMBRYO OF THE ANGIOSPERMS. 25

with immediate denial from our knowledge of the phylogeny of

seeds.

In her later papers, Miss Sargant (: 03, : 04) fails to reiterate

the above hypothesis of the reduction factor but says: “ These

considerations have led me to look upon the Monocotyledon as

an organism adapted primarily to a geophilous habit," and

* Suppose a race of primitive Angiosperms to be specialized as

geophytes. Their originally distinct cotyledons become more

and more closely united in order to economize material. In the

end a single cotyledonary member is formed by their complete

fusion. A monocotyledonous race might easily be derived in

this way from one with two cotyledons." While it is possibly

true that the development of cotyledonary tubes has resulted in

some dicotyledons through adaptation to a geophilous habit;

just how this habit might have caused a fusion and subsequent

reduction of the blades of the cotyledons, Miss Sargant does not

make clear in any of her papers; and how the habit should

finally force the cotyledon into the subterranean position char-

acteristic of monocotyledons receives no explanation at all.

Furthermore, her hypothesis would seem to require that the

primitive angiosperms were not geophytes. It is now commonly

held that the angiosperms are the progeny of pteridophytic

ancestors, and it might be well to consider that the geophilous

habit is quite prevalent among the Pteridophyta.

Finally, the entire structure of. Miss Sargant's theory is built

upon the assumption that cotyledons are morphologically foliage-

leaves, But we have already found that this assumption is dis-

proved by our knowledge of the form, structure, and develop-

ment of cotyledons. To make her theory seem tenable, Miss

Sargant must first make plausible this assumed premise on

which the validity of her hypothesis so largely depends.

RECAPITULATION.

The great value ascribed to the embryo in the systematic

classification of the Angiosperms early brought such embryos

into prominence in botanical literature. Thus we find that

angiospermic embryology embodied an extensive knowledge

26 THE AMERICAN NATURALIST. (VoL. XXXIX.

before any careful work had been done on the cryptogams. As

a result an interpretation of the angiospermic embryo was

evolved wholly from evidence obtained from angiosperms and

without reference to any evidence which cryptogamic embryos

might furnish. This interpretation in the hands of the system-

atists soon became a fixed creed which has come down to the

present day as built upon facts too well established to be

questioned. Some morphologists have, it is true, attacked this

creed, but have failed to lessen in the slightest degree its

general acceptance.

Because the cotyledons of certain plants assumed the func-

tion and approximated the form of leaves, a morphological leaf-

value was, from the first, ascribed to them. This hypothesis,

framed on simple analogy, is the self-evident fact which consti-

tutes the basis for all later acceptable embryological considera-

tions. If cotyledons are morphologically foliage leaves, that the

most primitive angiosperms must be those of which the cotyle-

dons most nearly approach foliage leaves, is a conclusion which

naturally followed. And hence the creed recognized the dicoty-

ledons as the most primitive and considered the monocotyledons

à race derived from them. Some theorists would derive the

monocotylous condition from the dicotylous, by the abortion of

one cotyledon, and others, through the fusion of the two cotyle-

dons into a single member. |

Following, and followed by others, the writer has concluded

that cotyledons are not metamorphosed foliage leaves. The

writer has further suggested that they are primarily haustorial

organs originating phylogenetically as the nursing-foot of the

Bryophytes and persisting throughout the higher plants; that

the monocotylous condition is the more primitive and that the

dicotylous condition has arisen through a bifurcation of an origi-

nally single cotyledon,

There are, it is true, certain dicotyledons which show a ten-

dency to reduce one cotyledon and others in which a partial or

complete fusion of the cotyledon petioles undoubtedly takes

place, yet there is no evidence to

tion of either process in ex

lous condition.

justify the sweeping applica-

plaining the origin of the monocoty-

No. 457.] EMBRYO OF THE ANGIOSPERMS 27

The embryos of the so-called anomalous dicotyledons can as

readily be interpreted as demonstrating the bifurcation of one

cotyledon as proving the fusion of two, and if we take into

account the course of events in their ontogeny they support the

former hypothesis in preference to the latter.

While, as mentioned above, some few dicotyledons show a ten-

dency to reduce the cotyledons there is an opposite tendency far

more prevalent among dicotyledons to produce lobed, bifid and

bipartite cotyledons ; undeniably a process of splitting.

Finally if the foliar-theory of cotyledons can be established

the writer's entire hypothesis must fall. If the adverse hypoth-

eses are to be proven, the foliar-theory must first be established.

THE PHYLOGENY OF THE COTYLEDON.

In a paper now in preparation, the writer will endeavor to

demonstrate the validity of his hypothesis concerning the phy-

logeny of the cotyledon. A previous paper (:02) on this sub-

ject only served to indicate in an indefinite way the scope of the

theory. Since that time continued investigations in the field,

laboratory and library have yielded evidence which bears out to

a remarkable degree the fundamental idea, at the same time fur-

nishing the necessary details for a more exact formulation of the

hypothesis. The following outline illustrates the application of

this hypothesis to plant embryology.

Cryptogamic embryos.— The first regional differentiation of

the body-tissue.of the sporophyte was into the spore-containing

capsule and the bulbous nursing-foot ; the function of the former

being the bearing and protection of the spores, that of the latter

the absorption of nourishment and the furnishing of mechanical

support. Since these two regions form the bases for all later

elaboration of the sporophyte we may conveniently assign to

them the distinctive names of sporophore and haustrum. As the

haustrum and sporophore are not always distinguishable from the

first in the embryo we will find the term protocorm! quite ser-

1 This admirable term was-first used by Treub (88) to designate the * embry-

onic tubercules ” of various lycopods. The writer simply extends the use of the

term without seriously altering its original meaning.

28 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

viceable as designating the whole embryo before this primary

differentiation is complete, and the term »zetacorm for the plant

body after the differentiation of its permanent members. All

of the protocorm or only a portion of its tissue may be employed

in the formation of the metacormal primordia.

In the Bryophyta the haustrum remains embedded in the tis-

sue of the gametophyte throughout its own existence, but in the

Pteridophyta it acquires the habit of anchoring the sporophyte

in the soil after the tissue of the gametophyte is exhausted.

This seems to have at first resulted in the production of a large,

bulbous haustrum (Phylloglossum, Lycopodium cernuum) but

later some haustral tissue became modified into a distinctive

earth-boring organ, the root, a structure much better adapted

for penetrating and drawing water from the soil In Zycopo-

dium cernuum the bulbous haustrum may give rise to roots,

which in turn may be converted back into bulbous haustra.

While some lycopods produce large, bulbous, geophilous

haustra, among the pteridophytes, as a rule, a bulbous haustrum

is employed only in connection with the gametophyte, the haus-

tral tissue which penetrates the soil being differentiated into a

root. Thus the primary bulbous haustrum of the bryophytes

becomes differentiated in the pteridophytes into two distinct.

haustral organs; the nursing-foot or cotyledon — the haustrum

of the protocorm, and the root — the haustrum of the metacorm.

The capsular sporophore of the Bryophyta gives place in the

Pteridophyta to an axis bearing sporophylls. Because of their

position, the photosynthetic work falls upon the sporophylls,

and this very soon leads to a division of labor with a consequent

sterilization of some sporophylls as foliage leaves or euphylls.

While phylogenetically the sporophore precedes the haustrum,

the requirements of the former during its development upon the

latter, seems to have stimulated an ontogenetic acceleration of

the haustrum and a corresponding retardation of the sporophore,

so that in ontogeny a functional haustrum precedes the sporo-

phore. Thus in the embryogeny of Anthoceros and Sphagnum

we find that of the massive protocorms first developed the

greater portion is haustral tissue on which the sperophore stands

as a papilla. Among the pteridophytes the ontogenetic acceler-

No. 457.] EMBRYO OF THE ANGIOSPERMS. 29

ation of the haustrum is always apparent so that their protocorms

are essentially haustral structures from which the sporophore

sooner or later develops as an outgrowth. In Phylloglossum the

ontogenetic acceleration of the haustrum is most pronounced, a

large bulbous protocorm resulting, from which the sporophore is

differentiated at a quite late period (Fig. 2). As the protocorm

of this plant becomes geophilous, it develops leaf-like lobes of

tissue which carry on photosynthetic work. Bower ('94) terms

these protocormal leaves, protophylis, to distinguish them from

the leaves of the metacorm, the euphylls. With the specializa-

tion of the root as the earth-boring haustrum and the euphylls as

the photosynthetic areas, the geophilous protocorm with its pro-

tophylls disappears from the ontogeny of the higher pteri-

dophytes as we have already found. Perhaps, however, the first

leaf of some of these should be interpreted as a protophyll rather

than a euphyll.

In the embryogeny of Lycopodium and Selaginella an out-

growth from the protocorm serves to carry the embryo down

into the tissue of the gametophyte. This protocormal organ,

the suspensor, is limited to the lycopods among the pteri-

dophytes but is of general occurrence in the embryogeny of the

angiosperms.

The positional relation which the metacorm bears to the proto-

corm is remarkably different in different cryptogamic embryos.

In the Bryophyta the axis of the metacorm is coincident with the

axis of the protocorm, the haustrum of the latter developing into

the haustrum of the mature plant. With the advent of the

root as the haustral organ of the metacorm, the position in which

it is differentiated in relation to the sporophore determines the

primary axis of the metacorm. In some embryos the root is dif-

ferentiated out of the body of the protocormal haustrum, while

in others it appears as an outgrowth from this structure. In

Botrychium obliquum and Equisetum, the root appears diamet-

rically opposite the sporophore and hence the metacormal axis

transfixes the protocorm, the tissue of the latter becoming a per-

manent' part of the metacorm. In Selaginella, the metacormal

axis is differentiated through the tissue of the protocorm, the

suspensor being on one side of the axis, and the cotyledon on the

30 THE AMERICAN NATURALIST. [VoL. XXXIX.

other (Fig. 3). In the leptosporangiate ferns, the sporophore

and root appear as adjacent outgrowths from the protocorm thus

leaving the haustrum of the latter as a lateral cotyledon on one

side of the metacormal axis (Fig. 4).

Angiospermic embryos.— In the embryogeny of an angiosperm,

a more or less massive protocorm is developed which may, or

may not employ a suspensor. The form of the protocorm varies

greatly, depending upon the shape and size of the seed, the extent

and vigor of the endosperm, the duration of intraseminal devel-

opment and the many other peculiar conditions presented by the

seed habit. The sporophore arises as an outgrowth from the

protocorm and its intraseminal development is, as a rule, quite

restricted. The metacormal axis is always differentiated through

protocormal tissue. (Figs. 5, 6, and 7.)

In the monocotyledons, the sporophore primordium usually

appears as a distinctly lateral outgrowth from the protocorm :

but with the establishment of the metacormal axis between the

sporophore and root the remaining protocormal tissue stands in

a lateral position to this axis and, as a lateral cotyledon on one

side of this axis, it functions during germination. As the spo-

rophore primordium of a monocotyledon differentiates into the

plumule the adjacent protocormal tissue grows forward around

it, often completely enclosing it.

In the dicotyledons, the protocorm early bifurcates and the

sporophore primordium arises as an outgrowth between these

two cotyledons which closely invest it during intraseminal growth

(Fig.7). In many dicotyledons, a new structure, the hypocotyl,

appears in the morphogenesis of the metacorm. The hypocotyl

is differentiated between the root and sporophore from tissue

which is phylogenetically haustral. During germination it serves

to elevate the cotyledons and plumule. The cotyledons upon

becoming exposed to the light usually become green and often

function for a considerable time as photosynthetic areas. The

assumption of the function of foliage leaves leads to the assump-

tion of the form of such leaves, and the cotyledons of some

plants approximate to a remarkable degree the form of: the later

euphylls.

Gymnospermic embryos. — That the gymnosperms in the ear-

No. 457.] EMBRYO OF THE ANGIOSPERMS. 31

lier stages of their embryogeny show a great diversity has been

known for a long time. That this diversity is but the more or

less restricted following of one general plan has been pointed.

out by Coulter and Chamberlain (: 032). Up to the present time

the knowledge of the later stages of their embryogeny has been

quite insufficient for determining the morphological values of

the embryonic structures. Recent investigation, however, has

served to elucidate some of the obscure points, and the interpre-

tation that would now be offered is as follows.

In Ginkgo a large spherical protocorm is developed in the

venter of the archegonium. The blastema (metacormal bud)

arises as an outgrowth from the deepest seated portion of the

protocorm and invades the tissue of the gametophyte by its own

growth. The stem and root primordia are both differentiated

entirely beyond the bulbous protocorm, the axis of the three

members being along one straight line (Fig. 8). Upon germi-

nation, the protocorm 1s the first member to be forced out of

the seed and it is followed first by the root and then by the

stem. Thus the protocormal haustrum, because of its position,

cannot be employed by the metacorm during germination as a

functioning cotyledon. If any structure is to remain in contact

with the tissue of the gametophyte, it devolves upon the append-

ages of the stem, and in Ginkgo we find the first two or three

euphylls functioning as absorbing organs or pseudocotyledous.

Ginkgo undoubtedly shows, in its embryogeny, the most primi-

tive condition of any of the gymnosperms, for it certainly shows

the least specialization. In Cycas (Fig. 9) a less perfect proto-

corm is developed and in Zamia (Fig. 10) a further reduction of

its bulk obtains. In fact it would seem that because of the

positional relation of the blastema to the protocorm the latter

cannot be made use of by the germinating embryo, and its dis-

use leads to an increasing limitation of the structure in gymno-

spermous embryogeny. |

In the cycads, protocormal tissue directly behind the blastema,

by rapid growth, carries the metacormal bud down into the tis-

sue of the gametophyte (Figs. 9 and 10). This beam he

suspensor, becomes an organ of importance and is retained by all

of the Coniferales. Their protocorms, however, consist of little

32 THE AMERICAN NATURALIST. (VoL. XXXIX.

more than a suspensor at the tip of which the metacormal pri-

mordia are differentiated (Fig. 11).

The suspensor of a gymnosperm embryo is clearly not homol-

ogous to that of a lycopod or angiosperm embryo. In the gym-

nosperms, the suspensor is developed between the body of the

protocorm and the blastema and by its elongation serves to sepa-

rate these two structures. In the lycopods and angiosperms, it is

an outgrowth from the protocorm and has one free end. In

these embryos the metacormal axis is differentiated through the

body of the protocorm. .

Polyembryony sometimes occurs in both gymnosperms and

angiosperms through the production of two or more blastemata

by one protocorm.

UNIVERSITY OF MINNESOTA.

b BIBLIOGRAPHY.

AGARDH, C. A.

'2932. Lärobok i Botanik. Part ı.

BALFOUR, I. B.

:01. The Angiosperms. Address to the botanical section, Brit. Assn.

Adv. Sci. Glasgow. Nature, 64, 557—562.

BALFOUR, I. B.

:02. Angiosperms. Reprinted from the new volumes of the Encyclo-

pedia Britannica.

BOWER, F. O.

'94. Studies in the morphology of spore-producing members. Equise-

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BRUNS, ERICH. i

92. Der Grasembryo. Flora, 76, 1-33.

Cook, M. T.

:02. Development of the embryo-sac and embryo of Castalia odorata

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: 03. Morphology of Angiosperms.

COULTER, J. M. and CHAMBERLAIN, C. J.

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HENSLOW, G

'93. A theoretical origin of Endogens from Exogens through self-adap-

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: The morphology of the central cylinder in the Angiosperms.

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Mémoire sur l'Embryon des Gramindes, des Cypéracées et du

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:04. Anatomy of cotyledons. Bot. Gaz., 37, 3883-389.

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'11. Analyse botanique des embryons endorhizes ou Monocotylédonés,

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34 THE AMERICAN NATURALIST. (VoL. XXXIX.

SACHS, J.

'90. History of Botany. English translation.

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:02. The origin of the seed-leaf in Monocotyledons. The New Phytolo-

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more or

embry

ese diagrams which are

e various protocorms shortly after the differen-

yos

resplen represent sectional views of the

i tion ne the metaco rmat primordia. Haus tral tiame is indicated by — The

d regi i h i extending

REH the central region of the sporophore in to the tissue aries es course of

the primary axis of the metacorm. In Fig. p to 11, the line across each diagram indicates

All s sa tissue above this point is

the juncture of protocormal : and metacormal tissue

originated b their differentiation.

inditum. - Phylloglossum. 3. ee 4. Pteris. 5. Zeamais. 6. Alisma.

7. Bursa. 8. phe 9. Cycas. ro. Zamia. tr. Pinus.

NOTES ON THE COMMENSALS FOUND IN

THE TUBES OF CHZETOPTERUS

PERGAMENTACEUS.

H. E. ENDERS.

Waie I was collecting Chetopterus pergamentaceus during

the past summer on the shoals about Beaufort,! North Carolina,

I became interested in the commensals which occur with this

annelid, and their number and variety led me to study their

habits.

These annelids, which grow in broadly U-shaped parchment

tubes, are imbedded in diatomaceous, sandy shoals with from two

to five centimeters of their free slender ends (about seven milli-

meters or less in diameter) protruding above the sand flats at or

below low-tide level. These tubes serve as convenient temporary

shelters for several species of small animals, and as the perma-

nent abodes of others.

Of ninety-nine tubes collected and opened eleven were found

without commensals while the remaining eighty-eight enclosed

two annelids of the genus Nereis also one hundred and seventy-

six crabs of the species? Polyonyx macrocheles (formerly Porce//-

ana macruneles), Pinnixa chetopterana, Pinnotheres maculatus,

and one species of. “stone crab," Menippe? Polyonyx and

Pinnixa are found either singly or together in the same tube, but

usually in pairs, male and female, of a single species. Among

the number of tubes collected seventy-five enclosed Polyonyx in

pairs or singly (total 143) ; fifteen enclosed Pinnixa; two, Pin-

notheres, and one, a “stone crab," Menippe, while two serpulids,

1] am indebted to the Hon. Geo. M. Bowers, U. S. Commissioner of Fish and

Fisheries, for the privilege of occupying a table in the F isheries labøratory at

Beaufort, N. C., and to Dr. Caswell Grave, the director, for courtesies shown.

2I am also indebted to Miss Mary J. Rathbun, of the U. S. National Museum,

for the identification of the species of crabs.

3 The specimen was mislaid or lost at Beaufort, N. C.

38 THE AMERICAN NATURALIST. [Vor. XXXIX.

encrusted on a female Pinnixa, may be regarded as an accidental

enclosure.

The tubes of Chatopterus are not the only abodes of some of

the commensals named : Nereis is found among the shells, rocks

and sea-weeds ; Pinnotheres maculatus, in the shells of Pinna

semi-nuda like the related species, P. ostreum, in the oyster ;

whilst Menippe commonly keeps in hiding in crevices and pits in

rocks and shells. So far as I know, Polyonyx macrocheles and

Pinnixa chetopterana, beyond the young stages, are only very

rarely found free on the shoals, but Polyonyx ocellata is found at

Beaufort on the body of Limulus, and sometimes in old shells

dredged outside the harbor.

The sizes of the crabs range from two millimeters in width

to that of the full-grown animal (thirteen to fourteen millimeters

wide), and the smallest ones are of such a size that they could

-readily pass through the orifices of the tubes, and they probably

do so for I have frequently collected tubes with two adult crabs

and a single small one but rarely with three full-grown indi-

viduals.

. The position of the crabs in the interior of the tubes I learned

by keeping the Cheetopterus and crabs in glass U-tubes, to the

open ends of which the annelids constructed inverted parchment

funnels, which prevented their escape. While the commensals

move about with rapidity they remain at one end of the U-tube,

usually the one opposite that occupied by the annelid itself, but

when the annelid reverses its position they press past it to the

opposite end and there remain bathed in the passing current.

The annelids, Nereis, moved along the dorsal wall of the tube

and did not interfere with Chstopterus which occupied the

ventral portion of the tube.

The commensals, which are usually found near the orifices of

the U-tube, are advantageously located for securing food, which,

if it consists either of vegetable matter or of copepods and

various larvae which pass through the tube in the moderate cur-

rent of water, and the worms that may seek shelter in the tube,

is very abundant.

The commensals are permanently confined within the tubes

of Chzetopterus where the breeding is comparatively simplified

No. 457.] CHA TOPTERUS PERGAMENTACEUS 39

because of the presence, in nearly every instance, of male and

female in the same tube. I also found tubes containing males

only (4) or females only; among the latter the eggs on seven

females (six Polyonyx and one Pinnotheres) thus taken were in

various stages of development, while two other females had, just

a short time before capture, liberated their broods. The mature

male of Pinnotheres is small enough to pass into and out of the

orifices of the tubes, but how or when the eggs of the isolated

individuals of Polyonyx are fertilized remains an open question.

The breeding season of the two more common commensals,

Polyonyx and Pinnixa, extends through the whole summer.

Females with eggs in all stages of development, together with

females which had just liberated their broods, were taken in my

first collection, June 21st (1904), and even in my last collection,

October 25th, every full-grown female taken bore developing

eggs, or had very recently liberated her brood as shown by the

few imperfect larvæ clinging to the pleopods, or by the position

of the abdomen, or “apron,” not being closely appressed to the

body. At the time of the last collection the breeding season of

. Pinnixa must have been near its close but that of Polyonyx con-

tinued unabated.

The larvae do not long remain in the tubes after they are

hatched but soon find their way out and they may then be taken

in the tow in considerable numbers from June till November.

Young crabs, not over two or three millimeters in width, are

found in the tubes during the middle and latter parts of the

breeding season, but they are frequently overlooked because of

their tendency to press between the appendages or the folds of

. Chaetopterus and hide there. In this manner four young crabs,

about two millimeters wide, were overlooked when four tubes

were opened, and from each the worm together with two full-

grown commensals were removed, and only after the worms were

submerged in the killing-fluid did the activity of the crabs make

their presence known. Once in the tubes it is quite probable

that the crabs remain there and are later prevented, through

their own growth, from escaping.

The act of moulting was not observed in these commensals

but recently moulted individuals of Polyonyx were taken on

40 THE AMERICAN NATURALIST. (VoL: XXXIX.

three occasions, the “shells " of which, more or less nearly com-

plete, were still in the same tube with the * soft-shelled " crabs. -

When a worm in a tube dies the crabs in the same tube die as

a result of the failure of food and properly aérated water. Two

tubes were taken in which this might have occurred as was

shown by the nearly perfect condition of the extremities of the

tubes and by the presence of the bodies of three dead crabs

lodged in the necks of the tubes, which were only recently filled

with sand.

Whether or not commensalism is an advantage to Chaetop-

terus it seems to be a decided benefit to the crabs, Polyonyx

and Pinnixa, grown specimens of which are za7e/y found outside

the tubes. The advantage to the crabs is very clearly marked

by their prolonged breeding season — virtually an example of

protected industry.

ZOÓLOGICAL LABORATORY, JOHNS HOPKINS UNIVERSITY.

ecember, 1904.

.ON THE LARVA AND SPAT OF THE CANADIAN

OYSTER.

JOSEPH STAFFORD.

Upon opening the Marine Biological Station of Canada for last

summer’s work the acting director, Professor Ramsay Wright,

assigned to me the diagnosis of bivalve-larvee occurring in the

plankton.

The material was collected over the oyster-beds near Curtain

Island, off Malpeque, P. E. I. Oyster-larvae were first recog-

nized on the 25th of July from which time they were present

in the plankton collections until the 1st of Sept.

The free-swimming, pelagic larva of the oyster possesses à

characteristic color, brownish-red — suggestive of the soil of its

native island shores, a shade which enables it to be immediately

distinguished from every other bivalve-larva with which it is

associated. The shell is asymmetrical and inequivalve, the left

valve being larger, more convex, and with a large umbo, the

right smaller, flatter and with a moderate umbo. The umbos

have a postero-dorsal position and project backwards and upwards,

making the shell broader, deeper and squarer behind and tapering

but rounded in front. The largest measure .358 * .365 mm. in

length and height, but the height and shape vary according to

whichever side is turned towards the observer. Larv& as small

aS .131 x .138 mm. already possess the characteristic shape and

color.

The internal structure of the larval oyster offers some inter-

esting features. We have been accustomed to think of it as

vastly different from other bivalve-larvz, corresponding to the

early assumption of a sessile mode of life. This misconception

is due to lack of observation of plankton stages, embryologists

having jumped from early veliger or phylembryo to late pro-

dissoconch or even early nepionic periods.

When mounted on a slide the larvae are accustomed to remain

42 THE AMERICAN NATURALIST. (Not. XXXIX.

quiescent and from their deep coloration are difficult to examine

but sometimes a more transparent one permits certain organs to

be traced. When freshly collected and examined in a watch-glass

of pure sea-water many of them exhibit the greatest activity, .

protruding the velum between the antero-ventral margins of the

shell, expanding it somewhat like opening an umbrella, and swim-

ming rapidly about by the violent movement of its cilia. While

in motion the heavy shell is suspended below the expanded

velum. Jarring the watch-glass will cause the animal to

instantly withdraw its velum, at the same time snapping the

valves of its shell together and dropping towards the bottom.

Upon again assuming activity it may protude a long, slim,

ciliated foot from the middle of its ventral surface, just behind

the velum. The foot at this period is well developed and is a

most capable organ by means of which the animal can creep

rapidly about and forcibly flop its heavy shell from one side to

the other. It can also bend up along the outside of the shell

and perform feeling movements over all parts of the body within

the shell. Its lower or posterior surface sometimes appears

flattened or even grooved lengthwise and at a short distance

frum the base of attachment to the body there is a heel-like pro-

jection which is doubtless the position of the byssus gland. In

the proximal part of the foot, 7. e., about the center of the animal,

are right and left otocysts each containing about a dozen oto-

conia. A little before and above these, but more superficial, are

two lateral, black pigment-spots (eye-spots). Along each side,

past the base of attachment of the foot to the body, lies a series

of short gill-filaments, extending from the eye-spot backwards

and downwards to near the posterior margin of the shell ; in the

oldest free-swimming larvz there are eight, diminishing in size

from before backwards, the last ones being mere knobs ; their

lower ends are free, but their upper ends spring from one con-

tinuous axis of origin, that, behind the foot, joins its mate of the

opposite side near the margins of the mantle. The mouth and

cesophagus lie in the median plane immediately below and behind

the velum to which they are attached and with which they are

protruded and withdrawn. In the quiescent animal the gullet

lies between velum and foot, in the median sagittal plane as well

No. 457.] CANADIAN OYSTER. 43

as in, or very near, the median transverse plane of the body.

Here it passes dorsalwards, between the first gill-filaments, ex-

panding into the stomach with its large lateral liver-sacs. The

intestine passes backwards towards the right, and then forwards

towards the left, when it again turns backwards and upwards in

the left umbo, and finally downwards in the median plane, over

the posterior adductor muscle ; the greater part of its folds lie in

the larger, left valve. In front and above the velum is a trans-

verse adductor muscle, while below the posterior parts of the

umbos is a larger, transverse, posterior adductor muscle ; retrac-

tor fibers converge from the velum to points in the umbos.

Right and left mantle-folds line the inner surfaces of the valves.

Examination of eel-grass, rock-weed and other marine plants,

of shells, stones, sand and other objects, revealed no young spat.

Bundles of brush were tied to submerged rocks, or weighted

with stones and sunk at various places. These were carefully

examined at intervals but without result. Window-glass was”

cut into strips 2 x 6 in. and stood on end in crocks, about

a dozen in each held apart by wire racks, the crocks being then

set out below low-water level on oyster beds and made secure by

zuilding stones around them. Daily examination of the glass

was made until, on the 16th Aug., I found my first young

oyster-spat. It measured 1.030 X .876 mm. in length and depth

and exhibited the characteristic coloration of the pelagic larva.

In the centre of its dorsal surface could be distinctly recognized

the shell (prodissoconch) of the oldest free-swimming stage

(.384 X .369 mm.), securely fixed to the glass by its left valve.

The anterior adductor appeared to be moved slightly backwards

and upwards from its original position, and the posterior adduc-

tor had moved downwards and backwards to a position outside

the border of the prodissoconch. Behind it opened the rectum.

In front of the adductors and in a direction parallel with them,

slanting downwards and backwards, were the axes of two sets of

gill-filaments, the deeper (left) of sixteen long filaments with

their free ends pointing forwards or forwards and downwards,

the upper (right) of about half that number of short filaments

that ceased below the posterior adductor muscle. No foot

could be recognized. The new spat shell was very thin and

44 THE AMERICAN NATURALIST. | [Vor. XXXIX.

delicate, its prisms easily separating from each other at the mar-

gins, while beyond these at places the mantle was sometimes

protruded.

Three other spat oysters were procured on glass in the same

way, the dates and sizes being: Aug. 19, 1.20 x 1.58 mm.;

Aug. 22,.55 X .51 mm. ; Aug. 31, .953 x .861 mm.

Search was made daily for spat on natural marine objects and

on Sept. 2nd I found the first, on the outer surface of a half-

grown oyster shell. It measured 2.3 x 2.4 mm., but instead of

having a pink, red, or brown coloration as one would suspect

from comparison with the larval or earliest spat stages; Or,

instead of having a chalky-white appearance as one would judge

from comparison with the old oysters; it presented a shining,

dark metallic lustre with a few faint radiallines. From this

time onwards they were to be found in increasing numbers, and,

after being once shown them, the deck hands of the government

‘steamer Ostrea could also find them. Altogether I have

observed spat oysters on the shells of the oyster, mussel, clam,

quohog, bar-clam, razor-clam, round whelk, and on stones. The

objects with which they may be most easily conflicted are the

young of Crepidula fornicata and colonies of Ralfsia verrucosa.

At the time of leaving Malpeque, Sept. 20, the largest this year's

spat I had seen measured 6 mm. in height, had a dark steel

lustre, radiating ridges or lines, and very thin edges; the whole

oyster being thin and fitting so solidly against the supporting

shell as to require some force with a knife-blade to separate it.

As to the rate of growth my 4th spat oyster on glass was

obtained Aug. 31, when it measured .953 x .861 mm. and had

about sixteen gill-filaments. On Sept. 7 it measured 1.261 x

1.276 mm. and had about twenty-four gill filaments. A week

later it measured 1.661 x 1.75 3 mm. One might say that it

doubled its length and height in two weeks. The smallest

oysters were about the size of one’s thumb nail. I have put

out wire baskets containing numbers of selected, half-grown,

living oysters, having black spat attached, to be examined next

spring.

MONTREAL, 23 Dec. 1904.

A TABLE TO FACILITATE THE DETERMI-

NATION OF THE MEXICAN SCALE-INSECTS

OF THE GENUS ASPIDIOTUS

(SENS. LATISS.) |

T. D. A. COCKERELI

Or all the Coccidz injurious to cultivated plants, none are

more easily carried to new countries, or more likely to cause

trouble, than the species of Aspidiotus, sens. /atiss (including

Chrysomphalus, etc.). Some years ago I prepared for my own

use a table of the Mexican forms of this group which were

known to be or likely to prove of economic importance, using

only characters which could be determined with a hand lens.

This table is now presented with the hope that it will be useful

to those who have to deal with injurious Coccide. The deter-

mination from the scale should of course always be confirmed

by reference to a detailed account of the insect; but in the

majority of cases, at least, the indications of the table will be

found correct.

> . " . 2.

(on mango, Frontera)

ae Ckll.

9 scale much broader (on cactus, Frontera) bowreyi Cll.

9 scale minute, less than 1 mm. diam., Hu or very dark brown or

Bray : ; : : i ` 5

9 RER ie 4

9 scale very convex, exuvie Gomis Het " a ring various

plants) personatus Comst.

? scale broad evittorn, first skin exon (ou mesquite, Hermosillo)

prosopidis Ckll.

Scale dark with orange or copperred exuvie — . i A } 5.

Scale white or light colored, with darker exuvie ; : 8.

Scale blackish or brown, with concolorous or oes exuvie 14.

Scale pale or reddish, with concolorous exuviae . 19.

Exuviz lateral, at one end of the oval scale ; scale black "id more or less

grayish and whitish concentric strigation ; exuviae deep ips Vapor

9 scale elongated

9 scale circular or baai SOM.

1. 9 scale linear, 21 mm. long, : mm. broad.

. Small, about ı mm. diam., exuviæ covered, pem uppi when

. Scale convex (on various plants)

. Exuviz not conspicuous

. Scale light brown m

. Scale convex, dark gray cm mimosa, ER

. Scale light reddish brown (on various plans

THE AMERICAN NATURALIST. | (Vor. XXXIX.

Exuviz central or nearly so ; : à à ; 6.

Scale hardly 11 mm. diam., exuvie deep reddish (on oak, Amecameca)

N Putnam.

Scale 2 mm. or over in diameter

Scale slightly raised, the exuvie coppery, ER like (on many PV

aonidum (L.)

Scale very flat, exuvi flat, not B ence num pale orange (on Citrus,

etc.) sni Ckll.

Exuvie light yw or orange ya

Exuviæ at least partly brown or black 10.

Exuviz covered (Coahuila) ne Ckll.

Exuviz exposed (on various Das. $ bire var. zeriz, Bouché.

First skin black or dark brown, second orange (Salina Cruz.)

tricolor CkM.

The exuviz practically all of one color Il.

rubbed, then shining dark brown or black (on Yucca, u

Larger, exuviz conspicuous without rubbing i

RR (n

13;

Scale very dark N wih 3 a ha aie secretion (on

orange, Cuernavaca albopictus Ckll.

Scale grayish, border more or ib whitish el orange, Linares)

NEN var. Zeonzs Twns. & Ckll.

Scale flat

Exuviz black or very dark. conspicuous .

Jatropha ROME & di

Scale very dark 16.

mimos Coni.

Scale flat, dark brown ersee Comst.

. Scale covered by the epidermis of the EN the N black exuviz

alone exposed (Orizaba) .

Scale exposed i ; ; .

Scales 3 mm. diam. (San Lots Potosi . nigropunctatus Ckll.

Scales 1 to 1} mm. diam. (on Agave, Toluca) . agavis, Twns. & Ckll.

Scale rather convex, exuviz nearly marginal (on em crawit, Ckll.

Scale flat or flattish, exuviae not nearly margin

calurus Ckll.

20.

Scale light brown, exuviz not marked by a dot aid. ring (Tehuantepéc

City) : : reniformis, Ckll.

Exuvie marked by a i dat and rin 21.

dicipsi ibi Morg.

Scale darker (on Citrus, Oaxaca) oebelei, Twns. & Ckll.

BOULDER, COLORADO.

NOTES AND LITERATURE.

GENERAL BIOLOGY.

Lloyd and Bigelow’s Teaching of Biology.!— In the joint volume

by Professors Lloyd and Bigelow, on the teaching of biology in the

secondary schools, the first half of the book, under the sub-title

“ The Teaching of Botany and Nature Study,” comprising some 320

odd pages divided into ten chapters, is by Professor Lloyd. The

style, while at times a little abrupt, is convincing and forceful, and

much sound common sense is inculcated in this presentation of the

subject. The introductory chapter is of the nature of a general

exposition of the value of science in education and of the sciences

the especial value of biology. The author brings out clearly the

importance of biological training, not only from the facts which it

' teaches, but also, what is more essential, the discipline which it affords.

The nature study side of the question is first considered since that

subject is first demanded in the schools at the present time. Here

we find strong arguments for the necessity of intellectual honesty and

against that curse of nature study, sentimentalism. The pitfalls

which lie in the way of teachers, in the confusion of teleological and

causal interpretations of organic structures, are dwelt upon.

The subject of botany itself is begun in the following chapter and

the various aspects of the subject developed in the subsequent ones.

The greatest interest perhaps centers in the discussion of the differ-

ent types of botanical courses. Every modern botanist must agree

with the author in his advocacy of a dynamic point of view, rather

than the formal morphological one which arises from a lack of a

proper consideration of the physiological side of the subject. While

the necessity of some study of types is recognized, very cogent and

just criticisms are made of the extreme *type course," criticisms,

indeed, which apply not only to biology as taught in schools, but

also as taught in colleges.

The starting point for a botanical course will always be a moot

‘Lloyd, F. E. and Bigelow, M. E. Zhe Teaching of Biolegy im the Secondary

Schools. New York, Longmans. 1904. American Teachers Series. dvo,

Viii + 491 pp.

45 THE AMERICAN NATURALIST. (Vor. XXXIX.

question and must necessarily depend in a measure on the individual

teacher and the conditions under which he works. Here the fruit

is advocated as the point of departure, from which the student natu-

rally passes to the study of the seed and seedling, till finally the fully

developed plant and its organs are all taken up. In connection with

the necessary morphological and anatomical study, the physiology

and, to an adequate extent, the ecological relations of the plant, are

brought out. The author's attitude towards ecology will be appre-

ciated by many, for without in any sense undervaluing its interest

and importance he subordinates it so that it is not made the only

end and aim of botanical instruction. The consideration of types

follows, but the transition seems a little abrupt from what has gone

before. Whether, in the time usually available in schools, the stu-

dents could with advantage study such obscure forms as Mysqny.

cetes, must be a question.

The value of the book as a whole, to teachers, particularly to those.

who have not had the advantage of adequate preparation, cannot

but be great. It is essentially not a book which deals with fads,

the importance of nature study under the conditions which exist is .

recognized without exaggerating this importance, the use of botanical

instruction proper in higher schools is justified with reasonable mod-

eration. The attitude of the author towards essential questions is

wholesome and stimulating. While enthusiasm of the best kind is

strongly advocated, sentimentalism is frowned upon, honesty of

: thought and of observation is insisted upon. The dynamic point of

view, already referred to, that plants should be considered as living

organisms and not merely as aggregations of cells and tissues

arranged in interesting patterns, or as objects to be placed in hard

and fast categories, will undoubtedly serve to stir up those who tend `

to fall into a too formal conception of botany ; and the need of such

stimulus when the great mass of botanical instruction the country

over is considered, is probably almost as great as ever. Another

point of value is the warning against unreasoning acceptance of

teleological and causal interpretations, which bring about false con-

ceptions of the significance of structures. The great value of the

book then is in this plain straightforward attitude and the desire to

avoid and show others how to avoid, question begging ideas of form

and of function. As to the particular form of a botanical course for

secondary schools it is not necessary to assume any finality in the

arrangement suggested, nor is it necessary for the teacher to follow

exactly the plan — to be able to get a very useful stimulus

from the book.

No. 457] NOTES AND LITERATURE. 49

Practical notes as to laboratory equipment and so forth, conclude

Professors Lloyd's part of this volume and it should also be men-

tioned that at the head of each chapter copious and usually pertinent

references are given to articles and books which the reader may

desire to consult.

The second part of the book, entitled “ The Teaching of Zoölogy

in the Secondary Schools," covers some 248 pages arranged under

twelve chapters, and is by Professor Bigelow. In the first chapter

the aims of zoólogical teaching are discussed from the standpoint

of the secondary school and emphasis is laid on the importance of

zoölogy as a means of training the mind as well as an informational

subject. In discussing available matter for zoölogy Professor

Bigelow advocates a partial return to the study of internal anatomy,

including dissection, from which in the last ten years the secondary

schools have tended to withdraw. It is questionable whether this

proposal is sound, for, notwithstanding laboratory pretensions, the

teacher of zoólogy is bound to impart most of his knowledge by

authoritative statement rather than by demonstration and hence he

may draw his laboratory material from the many illustrations in

external anatomy rather than from internal dissection so often objec-

tionable to the pupil.

The importance of animal ecology, classification, embryology, palæ-

ontology, and evolution are reasonably urged but with the final apol-

ogy that perhaps these aspects of zoólogy, good in themselves, are for

want of time not possible in the school. 1f, however, we understand

Professor Bigelow aright the pupil is not to be treated in such a way

as to bring him to the state of a “finished” product at the end of his

School life, but he is to be turned out with a mind trained for mental

work and awakened by a flood of suggestions that will lead him in

later years to take an active interest in the intellectual life about him.

From this standpoint few subjects are more important than ecology,

palzontology, and evolution.

ood advise based upon actual experience is contained in the

chapter on laboratory method, and the advantages of the “ verifica-

tion” and “ investigation” methods are set forth so well that even

the strongest advocates of the latter must see that theirs is not the

only path to true knowledge. The conception of school “ physiology i

as a special application of zoölogy and its importance in connection

with this science is justly emphasized and ought to lead to a radical

reform and betterment in the teaching of this subject. The zoólogi-

cal text, like that of the botanical portion, is accompanied by copious

50 THE AMERICAN NATURALIST. [Vor. XXXIX.

references and list of books, a feature which alone makes the volume

of great importance to the teacher.

One feature in the present situation of biological teaching is

apparently not dwelt upon and that is the importance of high grade

teachers for such work. Doubtless this is taken for granted, but

it is certainly too true that the subjects included under biology are

often forced as side work upon uninterested teachers with the result

that the poor outcome is too frequently attributed to the subject

rather than to the conditions under which it is taught. Asa whole

the volume is an unusually sound body of suggestion and advise

which no teacher of school biology can afford to be without.

& P.

ZOÖLOGY.

A New Textbook of Zoógeography.! — Professor Arnold Jacobi

of the Forestry Academy at Tharandt, Saxony, has lately published

a small manual. It is with much pleasure and satisfaction that we

have read this little work, since it is the first general treatise of the

subject which pays due attention to the modern improved ideas with

regard to zoögeographical methods.

While all previous textbooks on this subject generally fall more or

less in line with Wallace’s method, giving chiefly an account of the

present conditions of animal distribution upon the earth’s surface,

and being satisfied with the creation of a “scheme” of animal dis-

tribution, Jacobi makes it the fundamental idea of his book, that the

creation of * schemes of distribution " is not the final goal of zoó-

geographical research, but only a means to facilitate it. He adopts

the view that no scheme whatever is able to explain all cases, that it

is possible to create different schemes for differerit groups of animals,

and that even then there are exceptional cases, which need further

research. That these exceptional cases very often find their explana-

tion in the geological history of the particular group to which they

belong, is also maintained by him, and he most emphatically declares

this latter study the most important branch of this science. Thus he

fully accepts the general principles of zoógeography as set forth

repeatedly by Ortmann.

The limited space alloted for the work made it impossible for the

! Jacobi, A. Tiergeographie (Sammlung Goeschen). Leipzig, 1904. 12°.

152 pp., 2 maps.

No. 457.] NOTES AND LITERATURE. 5I

author to give more than a mere sketch. But in this short sketch is

condensed a wealth of information that is of highest value for the

student. Only a few words shall be said here to direct attention to

the chief features of the book.

The whole is divided in three main divisions: the first part, intro-

duction, contains the discussion of general principles, part of which

has been mentioned above. The two other parts are entitled : General

Zoügeog: graphy, and Special Zoögeography. The former treats (in 9

chapters) of the general laws of animal distribution, the relation of

the range of animals to space, the means of dispersal and barriers to

it, the struggle for space, the difference between centre of origin, areas

occupied later on, and areas of survival. Further, the principal

physical conditions of life and conditions of dispersal are discussed,

and finally certain typical cases of distribution are selected as examples

for the laws laid down.

The last part, Special Zoögeography (17 chapters), contains first

a short historical sketch of the work done previously in this line.

Then follows a discussion of the schemes proposed for the division

of the earth in zoógeographical unites, a discussion of the scheme

accepted in this work (for continental life), and a sketch of the actual

distribution of selected groups of animals (Mammals, Birds, Reptiles,

Amphibians, Freshwater Fishes, Insects, Land Snails, Earthworms).

The last chapter treats of marine life and the laws of distribution

governing it.

It is only to be regretted that the author did not have an oppor-

tunity to more fully discuss certain points, and chiefly, to go into

detail with regard to the geological development of the present

condition of animal distribution: but lack of space explains this.

Another exception might be taken with reference to the scheme

accepted for the distribution of land animals: but since this point is

to a degree a matter of personal taste with the author, we shall not

discuss it here. A E

Watchers of the Trails.'— Prof. C. D. G. Roberts’ latest collec-

tion of animal stories, Ze Watchers of the Trails, does not fulfill the

promise of his earlier Kindred of the Wild. lt suggests rather the

endeavor to work up the poorer ore from a once rich vein. We can

not be expected to follow the fortunes of a dragon-fly larva with the

same interest that held us in the story of the bull-moose, the " King

' Roberts, C. G. D. Ze Watchers of the Trails. Boston. L.C. — Co.

1904. Svo, pp. 161. With many illustrations by Charles Livingstone Bull.

52 THE AMERICAN NATURALIST. (VoL. XXXIX.

of the Mamozekel.” The only distinctly new point of view in the

volume under discussion is the study of domestic breeds in a wild

environment. “The Alien of the Wild," describes the fortunes of a

bull who is born and reared in the wilderness. London has how-

ever already entered this field in Zhe Cal of the Wild.

In Prof. Roberts’ earlier volume there is an interesting essay on

the evolution of the animal story, a sort of confessio religionis of the

literary naturalist. We quote two sentences. “They [the naturalists -

of the new school] are minutely scrupulous as to their natural history,

and assiduous contributors to that science. But above all they are

diligent in their search for the motive beneath the action." It is

significant that Prof. Roberts, to judge from this essay, seems unac:

quainted with the school of which Hudson (7%e Naturalist in La

Plata), and Belt (Naturalist in Nicaragua) are noteworthy examples.

The present volume contains a prefatory note in which Prof. Roberts

replies briefly to the charge, made by Burroughs, “of ascribing to my

animals human motives and the mental processes of man." This

prefatory note is an important contribution to the literature of the

animal story controversy, inasmuch as it reveals the fundamental dif-

ference in temperament between the scientist and the literary artist.

Prof. Roberts claims that a boyhood spent at the edge of a great

wilderness fits a sensitive, sympathetic nature to portray wild life

truthfully. It certainly has fitted him to call up in his fellow-men

the mood which he himself experiences in the forest gloom. It does

not necessarily fit him to tell us how the animals themselves feel.

Whether in this particular volume, he has always, as he claims, been

at particular pains to guard against ascribing motives on insufficient

evidence, it is impossible to prove one way or the other. But when

we read (p. 140) that all the wild kindred near a lumber-camp, which

had spoiled their hunting, despised the camp dog as a renegade and

traitor, and that they would have felt more satisfaction in taking ven-

geance on him than on his masters, we wonder how Prof. Roberts

knows their minds so intimately. That the dog was killed by a

wild-cat seems to have been the only fact in his possession. He

says that the wild-cat went off, “elated from his vengeance.” Most

juries of scientists would, we fear, sustain Mr. Burroughs’ charges.

For Prof. Roberts’ skill as a Ben artist we have a great admira-

tion. His story of “The Truce,” in the present volume is a thor

oughly admirable piece of work. The book is isch illustrated by

‚Charles Livingstone Bull.

No. 457.] NOTES AND LITERATURE. 53

Shells of Land and Water.! — This work is a diversion from the

usual type of conchological publications, the author endeavors to

popularize the study of the mollusks by a narrative. A quartette

consisting of a professor and three students, take various trips to the

“homes " of the land, fresh-water and marine species; these trips are

supplemented by frequent visits to the museum, thus in a general way

all of the more important groups are studied. Their first excursion

is to the “home” of the fresh-water clam, then a day with the snails

of the pond, river and brook, followed by a visit to the museum.

The homes of the land snails are next invaded and the evening is

spent in the snailery. The next chapter is “ how snails eat” with

figures of radula, jaws, etc. To study the exotic forms the museum

is again visited. In the same manner the marine forms are studied,

with instructions for dredging and preserving specimens. The work

closes with “some books to study" and a glossary of technical

terms.

The book contains 175 pages, the illustrations in the text, of

which there are upwards of 150, are excellent and well selected,

while the eight colored plates are beautiful examples of the three

color process; the work is also embellished by six half-tone plates

from photographs showing the homes of the various mollusks. To

those taking up the study of conchology as a pastime the work is

admirably adapted.

C WT

BOTANY.

Pfeffer’s Plant Physiology. — The completion of the second edi-

tion of Pfeffer’s Pflanzen physiologic? is a significant event. Ten

years ago Pfeffer began the revision which has just been completes

It would have been finished earlier but for the continued ill health of

the author. Pfeffer’s aim, as pointed out in reviews of the parts

which have previously appeared, has been to present the science as

1 Baker, F.C. Shells of Land and Water. A familiar Introduction to the

Study of Mollusks. Chicago, Mumford, 1903. 8vo, xii + 262 pp. 215 m d

* Pfeffer, W. Pflanzenphysiologie. Handbuch der Lehre vom Stoffwechsel u

Kraftwechsel in der Pflanze. 2 te Auflage, 2 vols., Leipzig, Engelmann, un

3 American Naturalist, vols. XXXII, pp. 450-1, 1898, and XXXVI, pp. 594-5»

1902.

54 THE AMERICAN NATURALIST. (VoL. XXXIX.

it is at present, to separate fact from theory, to examine each hypoth-

esis, discarding the false and emphasizing the probably true. Be-

sides the enormous amount of reading required, Pfeffer and his

assistants have done a great deal of experimental work, testing in his

own laboratory the work and conclusions reported by others. The

result is a critical mastery, on Pfeffer's part, of the whole subject of

plant physiology, such as no other man possesses, and the fruit of

this mastery is his book. The book, in presenting the science as it

now is, shows what is known and thought, how much more this is

than when the first edition was published nearly twenty-five years

ago; it shows also how indefinite our knowledge is, how inadequate

our thoughts, and how limited the Geld of investigation has hitherto

been. As remarked in a previous review, the plant physiology of

to day is the result of the study of higher plants mainly. The lower

plants have been more carefully studied by physiologists during the

last five years than ever before. The results of this study are evi-

dent and valued. When the physiology of these plants is understood

even to the extent to which we now understand the physiology of

higher plants, plant physiology will bear a different aspect from what

it does to-day. In the second as in the first edition, Pfeffer divides

his subject into Stoffwechsel and Kraftwechsel. To these classical

headings a third is now sometimes added, Farmwechsel. Though

_ this last is but a special aspect, a special result, of the other two, it

is a result which will certainly become increasingly important as it

becomes increasingly evident from the experimental investigation of

simpler plants.

From Pfeffer's book it is clear that the study of the influence of

the various factors of the environment upon the form of living :

organisms stands, in results, far behind our knowledge of these fac-

tors upon the immediate behavior of living organisms. In this last

part of the Handbuch we have mainly the subject of movements.

These are examined in detail. The mechanics of movement are

better understood than the action of the stimulus upon the living

organism, but in both cases the phenomena are so complicated and

often so contradictory in different forms that it is impossible to make

a general statement of the subject which would be both clear and

truthful. For this reason this part of Pfeffer's book possesses in the

extreme those qualities for which the earlier parts have been most

severely criticised, viz., lack of definite summary statements, repeti-

tions, and minute argumentative criticism. Summary statements

which would be true cannot now be made. Repetition is unavoid-

No. 457.] NOTES AND LITERATURE. 55

able because of the original division of the subject, but it is always

a repetition from a different standpoint, giving the reader a more

comprehensive view of the subject. And only by minute criticism

of what has been published is it possible to distinguish fact from

theory, and well-founded theory from that which is only plausible.

This book will serve as the basis, the inspiration, and the critical

guide of the investigations of the next twenty years. The future is

not likely to give us another book by one man who is master of the

whole field. This book stands as a monument to Pfeffer's learning.

The books which follow it will be written by several masters working

together, as is already the case in animal physiology.

It may not be out of place to mention here that the Philosophical

Faculty of the University at Góttingen have awarded the 12,000

mark prize of the Otto Vahlbruck Foundation to Pfeffer, justly

considering his 2/fazzenpAysiologic the most worthy contribution to

botanical science which has been made in years.

The excellent English translation by Ewart, the first two parts of

which have appeared,! will be cordially welcomed when completed.

GER

1 Published by the Clarendon Press, Oxford.

CORRESPONDENCE.

Editor of the American Naturalist.

Sir: — I have only recently seen in the American Naturalist

for July-August the review of a revision of Professor Orton's Com-

parative Zoölogy which I prepared and which was issued last year by

the American Book Company. As the reviewer makes certain very

erroneous implications I am led to send this communication with the

request that you permit it to appear in the Naturalist.

About ten years ago at the request of Mrs. Orton I made a

revision of Professor Orton's Comparative Zoölogy which was pub-

lished by Harper and Brothers. In this edition it was impracticable

to reset the book, and all new matter, except verbal changes, was

placed in an appendix. This edition, I understand, is still in use in

some schools and is known as Orton's Comparative Zoölogy, revised

by myself.

More recently, at the request of the American Book Company and

with the cordial approval of Mrs. Orton, I prepared the edition

which is the subject of the review mentioned. This revision was

undertaken largely for the purpose of meeting the wishes of certain

schools that desired to continue using Professor Orton's book but felt

the necessity of introducing practical work, of following a more

modern system of classification, and of having a more logical

arrangement of the text than the earlier edition afforded. When

deciding upon the title for the new revision the publishers contended

that it must be so worded as to avoid the confusion which would

inevitably arise in the schools and inthe trade if the two editions

bore the same title, it being their intention to continue the publica-

tion of the earlier revision. For this reason the name was changed

to General Zoölogy, Practical, Systematic, and Comparative, Being

a Revision and Re-arrangement of Orton’s Comparative Zoölogy, a

title which fully describes the character of the book. From the

letters which passed between the publishers and myself regarding

the title, I quote from one concerning a form of title-page which was

submitted to me but which I rejected because it did not express fully

enough the fact that the present edition claims to be nothing more

than a revision. “As to having my name standing practically alone

58 THE AMERICAN NATURALIST- | (Vor. XXXIX.

as the author of the book, I have very strong conscientious scruples

against it. The book, even as it stands, is really Orton's work, for I

have added only a comparatively small amount, and I do not want

to appear to have appropriated another man's book. But this, I

fear, is just how it will look unless Orton's name is given, as it

deserves, more prominence on the title-page. If I had re-written the

book, then we might say, perhaps, * Based on Orton's Comparative

Zoology, but, as matters stand, the book zs Orton’s Comparative

Zoology, with some changes and additions of my own, to be sure,

but they are hardly sufficient in number or importance to warrant me

in assuming to have made such a radical change as to justify my

being called the author." In the same letter I suggested that in

order to avoid confusing the two editions the trade name for the new

one might be the “ Orton-Dodge General Zoólogy." The first print-

ing of the book was sent out without Professor Orton's name on the

cover, a most unfortunate error and one which no one regrets more

deeply than I do, but the omission was made without my consent or

knowledge and I am in no way responsible for it. The publishers

promptly corrected the mistake at the next printing of the volume.

In justice to the American Book Company I wish to state also

that to the best of my knowledge the advertising matter sent out

regarding the book has never represented it to be “a mew one,” as

the reviewer would have us believe. I have carefully examined all

of the several catalogues, folders, etc., in my possession and all state

that this is “a revision and re-arrangement of Orton's Comparative

Zoology," and describe fully the extent and character of the changes

made. Furthermore, in various expressions attention is called to

this fact no fewer than three times in a preface of less than that

number of pages. It is, consequently, a most preposterous supposi-

tion that anyone can be misled as to the nature of the book.

Finally, if, in spite of all efforts to the contrary, I have not made

my position clear, I will say for the sake of those who may be inter-

ested in the matter that I deny most emphatically the implication that

I have or have had any desire, intention, or expectation to receive

credit which properly belongs to Professor Orton, my sometime pre-

decessor in this institution.

Very truly yours,

CHARLES WRIGHT DODGE.

UNIVERSITY OF ROCHESTER, :

(Nos. 455-456 were issued Jan. 10, 1905.)

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THE

AMERICAN NATURALIST.

Vor. XXXIX. February, 1905. No. 458.

THE BONES OF THE REPTILIAN LOWER JAW.

J. S. KINGSLEY.

As ıs well known, the lower jaw in the Reptilia consists of

a number of bones to which, eighty years ago, Cuvier gave

names, repeating the descriptions with slight alterations in the

second edition of his work on fossil bones (1836). He described

the elements in the jaw of crocodiles, tortoises, lizards, and

snakes, in the order named. Since his day different anatomists

have altered. these names for various reasons or have applied

them to different bones from those to which they were originally

given. It has recently become necessary, in connection with

Some investigations, to revise the nomenclature of these ele-

ments, the results of which are given below. Williston has

recently pointed out the necessity of some changes.

Cuvier recognized, at most, six bones to which he gave the

names articulaire, surangulaire, angulaire, complementaire or cor-

onoidien,! operculaire, and dentaire. These were given English

forms by Owen, who changed the names of two. The oper-

culaire he renamed the splenial so as to avoid confusion with

! He refers to an earlier work by Adrien Camper (Ann. Mus. Nat. Hist., Paris,

xix, 1812) for a previous use of the term coronoidien, but Camper merely refers

to the parts as the apophyses coronoides.

60 THE AMERICAN NATURALIST. [Vor. XXXIX.

the operculum of fishes, while for the complementaire he

adopted the alternative coronoid because of its resemblance

to the earlier named coronoid process of the mammalian jaw.

Other names have been changed by other authors.! Thus Wag-

ner calls the articulare the pars angularis, the dentary the pars

alveolaris,the angulare the 5. complementaris posterior, the sple-

nial the 2. comp. anterior, and the surangular the 5. comp. exterior,

while Brühl calls the splenial the marginale ; the surangular and

the coronoid, the ecto- and endo-complementare. Baur (Anat.

Anz., xi, 1896) has attempted to homologize these bones in dif-

ferent reptiles, but it would seem that he has fallen into one or

two errors, by taking the turtle rather than the crocodile or the

lizard as his basis. As will be seen below there is practical uni-

son in the use of terms by Cuvier in both crocodile and lizard

while the turtle exhibits some differences, and again, to use the

turtle as the basis would introduce no little confusion into the

literature. So I have adopted the lizard as the basis of my

work.

Practically all authors are agreed upon two of the elements,

the dentary and the articulare, the first forming the anterior

bone of the lower jaw, the latter being developed by ossification

in the posterior part of Meckel’s cartilage and forming a bone

by which the lower jaw is articulated with the quadrate.

In an embryo of the lizard Sceloporus in which the centers of

ossification have appeared, reconstruction from serial sections

shows the following elements (Fig. 1). Meckel's cartilage (zz)

is a long, slender, slightly curved cylindrical rod, the cartilages

of the two sides being continuous at the symphysis of the jaw.

Just in front of the articulation with the quadrate, a strong dor-

sal process marks the anterior boundary of the articular facet

(4), the cartilage extending a short distance behind this point.

The most posterior ossification is a long and slender bone

(da) which extends backwards nearly to the posterior end of

the meckelian. Behind, it lies on the lower inner surface of

the cartilage, but farther forward it rises on the inner surface.

: ‘No attempt has been made to find all the terms employed, or to trace each to

its earliest use.

No. 458.] REPTILIAN LOWER JAW. 61

Later this element fuses with the bone ossifying in the posterior

end of the meckelian, thus forming a part of the articulare,

which, as is well known, consists of both cartilage and dermal

constituents in the Lacertilia. For this dermal element, which

in some reptiles is distinct throughout life, I have adopted the

term dermarticulare.! Its characteristics are its position on the

posterior inner side of Meckel's cartilage, its inferior margin

being overlapped by the angulare and its anterior end, which

lies ventral to the coronoid, by the splenial element next to

be described.

The angulare (az) lies on the ventral surface of Meckel's

cartilage, its posterior end reaching to about the middle of the

dermarticulare, the lower margin of which it overlaps. The

splenial (s) lies on the inner surface of the meckelian, its pos-

terior end overlapping the anterior end of the dermarticulare.

The coronoid (c), which lies on the inner side of the jaw dorsal

to the splenial and the anterior end of the dermarticulare, needs

little description.

On the outer side of the jaw are the dentary and the sur-

angular bones. The dentary (4) occupies the anterior two

thirds of the jaw, bending below the meckelian so as to be visible

beneath it from the inner side, while above, it makes a broad

in-curved and down-curved plate, the future alveolar surface.

The surangular (sa) lies in the posterior third of the jaw,

extending backwards behind the articulation but not quite to the

posterior end of the meckelian, while below it hardly reaches the

ventral border. Its upper margin arches in a broad curve above

the meckelian from which it is separated by a large space.

The changes involved in the future development are exten-

sions of allthe bones so that the meckelian is covered on both

inner and outer surfaces and in the coössification of articulare

and dermarticulare to a single element (Figs. 2, 2a). It will be

seen that these parts agree in names and positions with those

described by Cuvier. The only difference between his account

and that given here is the recognition of the dermarticulare as a

! This term has been used in the ganoids by van Wijhe. In some instances

the element he has so called is clearly homologous with the dermarticulare of the

reptiles but in others (Amia) it is a different form.

62 THE AMERICAN NATURALIST. [VOL. XXXIX.

distinct element, the existence of which has been noted, although

no name has been given it, by later writers. The problem is to

homologize these elements with those found in the lower jaw of

other reptiles, in some of which Baur believed that he had dis-

covered a distinct bone which he has called the presplenial.

In the mosasaurs (Fig. 3) the matter is simple. Here derm-

articular (da) and articular (4) have united into a single bone,

the anterior splint of which occupies exactly the position, —

below the jaw behind, rising to its inner surface in front,— that

the dermarticulare does in the Sceloporus embryo. The splenial

(s) is greatly enlarged and extends far forward on the inner sur-

face. The other bones call for no comment, except that the

surangular (s. an) bends inwards over the meckelian in the way

` described for the lizard.

Baur begins his account with a description of the turtle

Emydura (Fig. 4) in which he recognizes his presplenial, but I

am compelled to think that here he has fallen into error. On

the inner side of the articular (a) is a long splint-like bone which

passes forward and upward on the inner side of the jaw (da).

This Baur interprets as the angular. In its position it clearly

corresponds to the dermarticulare which has failed to fuse with

the articulare proper. Below this is a bone as evidently the

angulare (av) but which Baur is compelled to call the splenial.

Hence, according to him, the true splenial (s) which occupies

the same position as in the lizard, is an additional element, the

presplenial. Baur's mistake! thus had its foundation in his

identification of the dermarticulare as the angulare although he

expressly recognizes the fact that in the Lacertilia the articulare

is composed of chondrogenous and dermal elements.

In the ordinary turtles, of which the snapping turtle

(Chelydra) may be taken as an example (Fig. 5), the splenial

is lacking, the angulare (az) extends back to near the posterior

end of the jaw, while the dermarticulare (da) forms a very large

plate on the inner surface, reaching forward to just beneath the

coronoid process (c).

Baur has also described and figured the jaw in Sphenodon

' Baur merely repeats the wrong identification of Cuvier.

REPTILIAN LOWER JAW.

No. 458.]

eloporus, cartilage dotted.

after Blanchard.

tuberculata,

1.— Reconstruction of elements in the jaw of an embryo Sce

ner and outer surfaces of jaw of /guana

haus, after Williston.

Fic.

Fics. 2, 2a.— Inn

Fic. 3.— Jaw of Platecarpus cor.

Baur.

m, Meckel’s

Fic. 5.— Jaw d C cpu" ieri

fter Baur.

ius, inner and outer surfaces.

da, Dermarticulare ;

Tic. 6.— Jaw

S. 7, 7a.— Jaw of apse Be luc.

ie an, Angulare; Í Canti: d, Dentary ;

a, Surangu

ilage; s, Splenial; sa, s.

64 THE AMERICAN NATURALIST. (Vor. XXXIX.

(Fig. 6), and his identifications are adopted by Howes and

Swinnerton. Yet it seems probable that here again the dermar-

ticulare (da) has been termed the angulare and the angulare (az)

the splenial. Judging by Günther's figures, which do not agree

with that of Baur, it is possible that the angulare is an angulo-

splenial as he suggests, but the observations of Howes and

Swinnerton show no separate elements. The articulare cannot

be a compound structure like that in the Lacertilia, for, in the

development no dermarticulare, other than that interpreted às

such here, occurs.

In the case of the alligator (Fig. 7) I feel less certain. As

is well known, besides the articulare (a), three bones form the

inner surface of the jaw, a bit of the dentary (7) being visible

near the tip. There can be no question about the coronary (c)

while the large plate extending forward from the coronoid (s) is

as Clearly the splenial, if the conclusions regarding the other

forms studied be correct. The remaining element (an) is the

more problematical. Baur calls it the splenial and thinks that

the angulare is fused with the articulare. It is clearly not the

splenial, but it exhibits characteristics of both angulare and

dermarticulare, being like the dermarticulare in its articulation

with the coronoid, but like the angulare in the rest of its extent.

There is no separate bone on the inner side of the articulare and

there is a large gap in front of the articulare, extending to the

coronoid, which in all other forms is occupied by the dermarticu-

lare. Hence until a study of the development shows that this

conclusion is untenable I prefer to call it the angulare and to

assume that the dermarticulare has failed to develop. It is the

angulare of Cuvier.

These comparisons need to be continued into the Ichthyopsida

and especially into the Stegocephala and the ganoids where con-

siderable confusion exists.

CONTRIBUTIONS FROM THE ZOÖLOGICAL LABORATORY OF

THE MUSEUM OF COMPARATIVE ZOÖLOGY AT HARVARD

COLLEGE. E. L. MARK, DiIRECTOR.— No. 160.

NATURAL AND ARTIFICIAL PARTHENOGENESIS.!

ALEXANDER PETRUNKÉVITCH.

WrrH the discovery by Oscar Hertwig, in 1875, of the essen-

tial nature of fertilization as the union of the nuclei of the two

parental germ-cells, the line of research in the branches of biology

dealing with reproduction became more clearly defined. While

on the one hand this discovery put an end to all guess-work, on

the other hand it threw light on the part taken in development

and heredity by both egg and sperm. To this was added later

the knowledge of the behavior of the centrosomes in fertilization,

the whole bringing us nearer to an understanding of the other-

wise incomprehensible phylogenetic separation of living beings

into two sexes, impelled by the necessity of amphimyxis.

Again, the theory of the individuality of the chromosomes and

the study of the process of reproduction in maturation afforded

us an insight, incomplete though it be, into those forms of

reproduction which are not accompanied by fertilization. New

questions were gradually evolved, but since they had their source

in facts recognized by everyone, they were so precise, that when,

five years ago, I entered upon the study of parthenogenesis 1n

the honey-bee, I had before me a very definite problem.

All this I purposely mention here. By the time I had pub-

lished the first part of my research and had gone on in the

Study of natural and artificial parthenogenesis, there began to

appear objections not only to the results of my own work, but

even to statements hitherto undisputed, as well as to the toe

Sober interpretations of facts. These objections were raised

! Read before Section F — Zodlogy — of the A. A. A. S. at the 54th annual

méeting in Philadelphia, 1904.

66 THE AMERICAN NATURALIST. (Vor. XXXIX.

not only by people unacquainted with the facts won by science

and with the methods of scientific research, as bee-keepers for

instance, but also by men of very considerable scientific educa-

tion, especially physiologists. It seems to me therefore season-

able to review briefly these objections, in order to determine

what, if anything, has been gained through this controversy,

so that we may know how the question of parthenogenesis now

‘stands.

Our knowledge of fertilization and parthenogenesis, acquired

in the study of many different animals, may be recapitulated in

the following words :

1. Both the egg ready for fertilization and the mature sperm

show a reduction in the number of chromosomes of their nuclei

to one half of that found in somatic cells. ;

2. No matter how many spermatozoa succeed in entering the

egg, the nucleus of only one of them, under normal conditions,

fuses with the egg-nucleus, thus restoring the chromosomes to

their original number. All other spermatozoa are absorbed.

3. The centrosome of the egg disappears after the second

polar cell is formed, its functions being assumed by the centro-

some of the spermatozoön.

4. In most parthenogenetic eggs no reduction of chromo-

somes takes place — only one polar cell being formed — and the

€8g-centrosome remains active. |

Now, all of the objections alluded to above are directed against

one or more of these four propositions. As, however, it is in

these propositions that our present understanding of partheno-

genesis is epitomized it is of urgent importance to discover how

much of truth these objections contain.

First of all I shall consider the objections brought forward by

the physiologist Bethe and the zoölogist Bresslau. Both claim

to find the essence of fertilization not in the union of the sperm-

nucleus with the egg-nucleus, but in the entrance of spermatozoa

into the egg. Bethe (:04) says explicitly: “I consider an egg

fertilized when a spermatozoón has entered it. What becomes

of this spermatozoön later on is another question.” He says,

further, that not alone the chromosomes of the nucleus enter

the egg, but also other substances, of whose fate we know

No. 458.] PARTHENOGENESIS. 67

nothing, and that we keep in sight a part, only, of the whole

phenomenon when we speak of fertilization as the union of |

nuclei. Bresslau (:04) supports nearly the same view, and dis-

tinguishes between ** Besamung,” or the entrance of spermatozoa

into the egg, and * Befruchtung " or fertilization in the sense of

Hertwig, Weismann, and others, 7. ¢., the union of the nuclei.

In one respect Bethe and Bresslau are right, that is, as to the

necessity of distinguishing between these two phenomena; but

it remains to decide which of the two phenomena exerts the

greater influence upon the development of the egg and may

therefore be considered the one essential to fertilization. This

question seems to me easy of solution in the light of recent

experiments and observations, There can exist no doubt as to

the importance of the union between sperm- and egg-nuclei.

The normal number of chromosomes is indispensable to normal

development. The paternal hereditary characters are trans-

mitted to the descendant by the chromosomes of the sperm-

nucleus. Even if the protoplasm of the spermatozoön, in those

cases where it succeeds in entering the egg (for it is frequently

cut off by the suddenly formed yolk-membrane), should possess

the power of transmitting by heredity certain paternal qualities,

yet, in the presence of the egg-centrosomes, it loses that power.

Nor can there be doubt as to the importance of the part taken

by the sperm-centrosome. It gives the stimulus to development

and controls the successive divisions. Without it there can be,

no development ; when hindered in the normal performance of

its functions, abnormal development results.

We now turn our attention to the phenomenon of the entrance

of spermatozoa into the egg. Does it make any difference in

the development of an egg whether one or several spermatozoa

enter it? No, for the nucleus of only one spermatozoön 1s

destined to unite with that of the egg. In those cases where

_ polyspermy exists normally, all spermatozoa with the exception

of one are gradually absorbed by the egg-protoplasm, and the

resulting development is the same whether the spermatozoa are

many or few; but when, as sometimes happens, they en not

absorbed by the egg-protoplasm, their centrosomes form inde-

pendent centers for cell-division, thus interfering with the nor-

68 - THE AMERICAN NATURALIST. [Vor. XXXIX.

mal development of the egg, and sometimes even proving fatal.

Abnormal development also follows where the egg-nucleus

unites with more than one sperm-nucleus.

Thus the entrance of a spermatozoón into an egg cannot be

regarded as in itself the efficient stimulus to normal develop-

ment. Moreover, it is possible by etherizing an egg, to prevent

the union of the sperm-nucleus with the egg-nucleus. By this

means one half of the egg, that containing the egg-nucleus,

develops parthenogenetically while the other, containing the

sperm-nucleus, develops merogenetically. Knowing all this, one

must realize that the simple fact that a spermatozoön has entered

an egg is relatively unimportant, though it is of course a neces-

sary step in fertilization, rendering possible the union of the. two

pronuclei.

I consider it therefore perfectly correct to hold to the old

definition of fertilization and to call an egg fertilized only when

the union of the nuclei is accomplished. This definition does not

take into account the behavior of the centrosomes, and rightly,

since these constitute only the stimulus, and the controlling

apparatus of division and are not as important as the chromo-

somes, 7. e, whether the division is accomplished through the

influence of the egg-centrosome, or that of the sperm-centrosome,

does not change thé outcome of the union of the pronuclei.

Applying the same standard to a definition of parthenogenesis,

we should expect to say that the latter represents development

without fertilization ; yet we shall see that such a definition is

too broad and that in order to avoid misunderstandings it is

necessary to restrict it in certain points,

Development without fertilization takes place normally in

many animals of different groups. Leaving out of considera-

tion reproduction by the division of the whole animal, we find

these three kinds of propagation: parthenogenesis, paedogenesis,

and budding. Under budding we understand development

through successive, regular mitotic cell-divisions, proceeding

from one or several cells. Parthenogenesis is always devel-

opment of an unfertilized egg and is introduced by a matura-

tion process, while the nature of paedogenesis is not yet known.

The facts that peedogenesis occurs in only a few animals and

No. 458.] PARTHENOGENESIS. 69

that these animals are very rare, make its study exceedingly dif-

ficult. We know no more now than was contained in the work

of Metschnikoff on Cecidomyia, the account of which appeared

in 1865, when the maturation divisions of the egg were still

unknown. Should further research show that pzdogenesis is —

also introduced by a process of maturation in the egg, it must

then be regarded as a case of larval parthenogenesis. If, on

the contrary, the maturation process is wanting in paedogenetic

development, it would be more reasonable to place paedogenesis

in the same group with budding. In any event it is a problem

by itself.

The process of maturation in the egg is without doubt equally

indispensable for parthenogenetic development and for that

resulting from fertilization; yet there is a great difference

between the two, the importance of which was at once recog-

nized by Weismann, its discoverer, many years ago. All eggs

requiring for their development fertilization, undergo a double

maturation division.. This results in the reduction in the num-

ber of chromosomes by one half. On the other hand, in the

majority of parthenogenetic eggs — the single exception being

that of certain insects — there takes place but one maturation

division, and in consequence, there is no reduction in the num-

ber of chromosomes. In this way the opportunities for variation

are much restricted. The exception to this rule is found in

those insects in which only one sex develops parthenogenetically,

and in the male individuals in those cases where both sexes de-

velop parthenogenetically. In such cases two maturation divi

sions invariably take place with a corresponding reduction in

the number of chromosomes. The insects which on account of

the possession of this peculiarity have been much studied lately,

are the ants and the bees. In these Hymenoptera it is only the

males that develop parthenogenetically. I have every anon

to re-affirm this, notwithstanding the recent objection raised

against it. ;

After what I have said about fertilization it is clear that

microscopic study, and that only, is able to show without error

whether an egg is fertilized or not. The development of an

aster around the centrosome of the spermatozoön after the lat-

JTO. THE AMERICAN NATURALIST. (VOL XXXIX.

ter has entered the egg, facilitates the finding of the sperm-

nucleus, which keeps its place close behind the migrating cen-

trosome. Were it not for the objections which have been raised

by men like Pflüger and Bethe, I should scarcely need to men-

tion that this sperm-aster develops in the same way throughout

the entire animal kingdom, that in polyspermic bee-eggs similar

asters appear in numbers equalling those of the spermatozoa

which enter the egg, and that also in the so-called drone-egg an

aster wöuld surely develop, should a spermatozoön enter it.

The experiments made upon the eggs of bees, consisting in

transporting them from one kind of comb-cell into another, in an

attempt to change their sex, have proved to be failures. Should

similar experiments, however, some day meet with success, it

would only show that it may be possible artificially to change

sex.! The objection that in drone-eggs the aster might not

develop because of the influence of the saliva of the workers

which take charge of the eggs as soon as they have been laid,

and that in consequence a spermatozoón, though present, might

easily be overlooked, does not bear critical investigation. Experi-

ments and microscopic preparations alike showed that the saliva

of the workers exerts no such influence. For when fertilized

eggs are treated with the same saliva, the aster none the less

develops. Or would the opponents of parthenogenesis — who

believe that a queen can by no reflex be impelled to fertilize

or to inhibit the fertilization of her eggs as she lays them in

worker-cells or in drone-cells — be bold enough to affirm that the

Workers treat the eggs with two different kinds of saliva, corre-

sponding to the comb-cells in which these eggs are laid? Yet

this is what the opponents of parthenogenesis claim. How

! Experiments in attempting to change sex artificially have been made by vom

Kati, by v. Buttel-Reepen, by myself, and by others with negative results.

Experiments with apparently positive results have been made and often described

by Dickel a German bee-keeper. I desire here earnestly to warn against the

attempt to use in any way whatsoever the experiments of Dickel without first

verifying them, as he has on several occasions in his scientific work practiced

deliberate fraud in an effort to support his theory, for which delinquency he has

frequently been called to account by v. Buttel-Reepen and myself. The history

of the falsely labelled bottles containing bee-eggs, together with my exposure of

this deliberate trick, made clear the absence of spermatozoa in drone-eggs and thus

demonstrated the efficiency of microscopic study.

No. 558.] PARTHENOGENESIS. 71

wonderfully complicated that reflex would have to be which

could stimulate to action at a given time only one of three pairs

of glands which possess a single duct common to them all!

There are still other difficulties in the way of these objections.

The union of the nuclei, not the presence of an aster, is the

essential of fertilization. Now, this union of the nuclei may

readily be observed, whether the aster lies in the same micro-

scopic section with the nucleus or not, and even when it does

not appear at all Since there is no union of nuclei in drone-

eggs, they are not fertilized. As this is the only reasonable

conclusion, it sounds strange to hear Pflüger (:03) say that to

claim parthenogenesis for the bee, is to adopt a false and insuffi-

ciently supported hypothesis, and that the queen-bee is probably

a hermaphrodite in which the male sexual glands have not yet

been discovered. Still stranger is the contention of Bachmetjew

(03), who says that the right wing of the drone and the left

wing of the worker develop parthenogenetically, while the left

wing of the drone and the right wing of the worker are the

result of fertilization, on the ground that the number of hooks

on their wings is subject to variation, displaying two different

maxima of frequency. If the theory of partial parthenogenesis

can find any support in facts, it is more likely to be applicable

to those cases of bee-monsters which exhibit a marvelous mosaic

of male and female characters.

If, however, more than one form of parthenogenetic develop-

ment can with certainty be recognized, should not microscopical

research be able to throw light upon the origin of these forms ?

The answer to this question may be looked for in the behavior

of centrosome and chromosomes. There can be no doubt that

in parthenogenetic eggs the egg-centrosome remains active, and

in Artemia salina, at least, we can easily see that it moves alone

toward the center of the egg to await there the nucleus, which

after the single maturation division, is destined to become the

first cleavage nucleus. Thus does the egg-centrosome in parthe-

nogenetic eggs maintain its individuality through all cell genera-

tions. In the fertilized egg of bees the centrosome of the

Spermatozoön becomes the active centrosome and as such passes

in turn into the spermatozoón of the next generation. We may

72 THE AMERICAN NATURALIST. (Vor. XXXIX.

therefore say that in all cases in which either both sexes, or even

one sex, invariably develop from fertilized eggs, every centro-

some (even that of the egg, which is destined to disappear) is a

descendant of a sperm-centrosome — a male centrosome, if I

may so call it. There is apparently a difference between this

and pure parthenogenesis, where every centrosome is a descend-

ant of the egg-centrosome and could be called a female centro-

some. Does such a difference in reality exist? If we believe

with Wedekind (:02) that parthenogenesis is an original, pri-

mary mode of development, we must admit that it does. But

this would mean that animals which are closely related to each

other differ in their phylogenetic origin. Is it not simpler to

admit that even in pure parthenogenesis the ostensibly female

centrosomes are descendants of a remote ancestral male centro-

some? It seems, indeed, as though in animals where fertiliza-

tion occurs only as a rare exception the males had gradually

disappeared yielding to hermaphroditism and parthenogenesis,

as Maupas (:00) has so beautifully shown for certain nematodes.

Still more important biological problems are connected with

the behavior of the chromosomes in parthenogenesis. In pure

parthenogenesis only one maturation division takes place and

the number of chromosomes remains normal; the individuality

of the chromosomes is preserved and thus the questions of varia-

tion and hereditary transmission are greatly simplified. Not so

in the case of that form of parthenogenesis in which the number

of chromosomes is reduced. I have elsewhere (Petrunkewitsch,

:02) pointed out that the great difficulties here encountered by

the theory of Weismann — which maintains not an essential, but a

qualitative difference only between the chromosomes — grow out

of the cessation of hereditary transmissible variability. There

seem to be fewer difficulties in the way of the theory of Sutton

‘ and Boveri,— who affirm that the chromosomes are essentially

different, — since I have shown — and still maintain after a care-

ful re-examination of my sections, in opposition to the objections

of Doncaster (:04) — that the number of chromosomes in the

first cleavage nucleus of the drone-egg again becomes normal,

probably through longitudinal splitting without a corresponding

division of the cytoplasm. I thought to find a support for

No. 458.] PARTHENOGENESIS. 73

Weismann’s theory in my observation that in parthenogenetic

eggs the polar cells, after a copulation similar to that of the

pronuclei, give origin through successive divisions to many cells

which may be easily traced as far as the gastrulation stage of the

embryo. My attempt to trace them still farther and to show that

the male sexual glands in bees develop from these cells, has met

with much criticism and requires confirmation. Doncaster, how-

ever, was able to prove in Nematus the accuracy of my observa-

tions as far as the beginning of the blastoderm stage. Although

I am still, and until convinced of error shall remain, an adherent

of Weismann's theory, I admit that the Sutton-Boveri theory

would be strengthened, if it could be shown with certainty that

I was at fault in my observations, and that the sexual glands of

the drones develop not from polar cells but from the pronucleus.

Future research will reveal the truth, but one thing is already

certain: in all parthenogenetic eggs hitherto studied, with possi-

bly the one exception of Nematus (according to Doncaster), the

number of chromosomes in the first cleavage nucleus becomes

in some way equal to that in the somatic cells. This is not

limited to animals, but applies equally well to plants! and is

consequently of fundamental importance. Yet it is not impos-

sible that in Nematus there is no reduction in spermatogenesis,

Which would lead to the same thing.

It is clear that to reach a solution in the problems connected

With the two theories of which I speak, we ought not to limit

our research to observation of normal parthenogenesis alone, but

rather to supplement such observation by the use of experiment.

Here two methods are possible, of which one is cross-breeding

and inbreeding, the other, artificial parthenogenesis and mer-

ogeny. Much light could be gained by experiments in the for-

mér upon animals like the bees, since such experiments would

have many advantages over sintilar ones made on animals

developing by fertilization only. Although this method prom-

ises much, it has never yet, I regret to say, met with scientific

application. ; |

By fertilizing enucleated eggs we obtain development by mer-

! Compare the observations of J. B. Overton (:04) on Thalictrum purpurascens.

74 THE AMERICAN NATURALIST. (Vor. XXXIX.

ogeny, which is characterized by a reduced number of chromo-

somes, and by the presence of the active sperm-centrosome. In

stimulating unfertilized eggs by chemical or physical means to

develop, we get what is called artificial parthenogenesis. As I

have elsewhere (Petrunkewitsch, : 04) tried to show, this develop-

ment is due not to a new formation of centrosomes,! but to the

stimulation to new life of the egg-centrosome, which is other-

wise destined to disappear. According as we apply the stimulus

before or after the second maturation division, we obtain differ-

ent results ; if before, we get development with the normal num-

ber of chromosomes, if after, then with the reduced number.

Now, it is interesting that both parthenogenetic development

with the reduced number of chromosomes and merogenic devel-

opment show abnormalities when compared with the develop-

ment of fertilized eggs. These abnormalities increase in inverse

proportion to the number of chromosomes left in the egg, an

indication of which is given in the experiments of Stevens,

which consisted in a dissection of the fertilized egg in the

amphiaster stage into two parts containing unequal numbers

of chromosomes. All this goes to show that neither merogeny

nor artificial parthenogenesis with a reduced number of chromo-

somes can be regarded as equivalent to natural parthenogenesis.

I call, therefore, these two forms, artificial, pathological, uni-

parental development. On the other hand, artificial partheno-

genesis with the normal number of chromosomes leads to appar-

ently normal development. I therefore call it artificial, true

parthenogenesis.

If we could cause an egg to develop by applying a pera en

before the first maturation division, the gap between partheno-

genesis and budding would be filled. Again, if we could. bring

about artificial parthenogenetic development through several

successive generations by stimulating the eggs at the three

different moments of their maturation, we might obtain valuable

‘If there are such de novo formations of centrosomes, as seems to be again

emphasized by the research of Yatsu (:04), it is nevertheless probable that in

counteracts possible teratological action on the part of the artificial centrosomes.

No. 458.] PARTHENOGENESIS. ; 75

results connected with the questions of individuality of chromo-

somes, determination of sex and variation. These are the prob-

lems to which my own study of parthenogenesis has naturally

led me and to which I am now seeking solutions in experiments.

In this way parthenogenesis, an important problem in itself,

becomes at the same time a method for the study of other and

greater problems.

BIBLIOGRAPHY.

BAcHMETJEW, P.

:03. Ein Versuch, die Frage über die Parthenogenese der Drohnen

mittels der analytisch-statistischen Methode zulósen. Allg. Zeit.

f. Entomol., Bd. 8, no. 2-3, pp. 37-44.

BETHE, A.

: 04. Entgegnung auf den Aufsatz von v. Buttel-Reepen in Nr. 4 dieser

Zeitschrift ^ Bienenwirtschaftliches Centralblatt, 1904, no. 11,

2 pp.

BREssLAU, E.

:04. See‘ Diskussion. Verhandl. Deutsch. Zool. Gesellsch., 14. Jahres-

vers. zu Tübingen. Leipzig, 1904, pp. 66-72, 73-77 passim.

DONCASTER, L. j

2 On the Early Development of the Unfertilized Egg in the Sawfly,

Nematus ribesii. Proceed. Cambridge Philos. Soc., vol. 12, part

6, PP. 474-476.

MavPas, E. i

:00. Mode et formes de reproduction des nématodes. Arch. zool. exp.

gén., sér. 13, tom. 8, no. 3, pp. 463-624, pl. 16-26.

OvERTON, FB eh

Ueber Parthenogenesis bei Thalictrum purpurascens. Berichte

Deutsch. Bot. Gesellsch., Bd. 22, Heft 5, pp. 274-283, Taf. 15.

PETRUNKEWITSCH, A. ;

: Das Schicksal der Richtungskórper im Drohneni. Ein Beitrag

zur Kenntniss der natürlichen Parthenogenese. Zool. Jahrb.,

Abth. f. Anat. u. Ontog., Bd. 17, Heft 3, pp. 481-516, Taf. 11-13.

P ETRUNKEWITSCH, A. :

:04. Künstliche Parthenogenese. Zool. Jahrb., Suppl. vii, F pee

Weismann, pp. 77-138, Taf. 8-10. Also separate, 62 pp. 3 Taf.,

904.

76 THE AMERICAN NATURALIST. | (Vor. XXXIX.

PFLÜGER, E. F. W.

:03. Ueber die jungfräuliche Zeugung der Bienen. Arch. f. d. ges.

Physiol., Bd. 99, Heft 3-4, pp. 243-244.

Also in Münchener Bienenzeitung, no. 20, 1903.

WEDEKIND, W.

:02. Die Parthenogenese und das Sexualgesetz. Verhandl. 5. Internat.

Zool.-Congr. zu Berlin, pp. 403-409.

YATSU, N.

:04. Aster Formation in Enucleated Egg-fragments of Cerebratulus.

Science, vol. 20, no. 521, pp. 889-89o.

THE ANGLE OF DEVIATION FROM THE NORMAL

VERTICAL POSITION AT WHICH STEMS

SHOW THE STRONGEST GEOTROPIC

RESPONSE.!

JULIA ANNA HAYNES.

INTRODUCTION.

SACHS (’82) seems to have been the earliest botanist to pay

particular attention to the relation between the angle of devia-

tion in orthotropic plant organs and the strength of the geo-

tropic response. He found, by experiment, that main roots of

beans and oak seedlings inclined 8 or 10 degrees from the verti-

cal, slowly or never came into the normal position, while if placed

at an angle of 80 or 9o degrees, the growing parts curved 80

or 90 degrees in a few hours. In his “Lectures on the Physi-

ology of Plants,” Sachs (87) also speaks of using in these

experiments, thick, rigid, long internodes of such flower-stalks

as attain considerable heights in short periods. The results led

him to the conclusion that zones of similar developmental stages

make various curvatures during the same time if they form

various angles with the vertical. That is, the curvature is

stronger, the more nearly the angle of deviation approaches to

a right angle. If, therefore, this angle of deviation is a right

angle, the maximum of growth-difference between the upper and

lower sides is attained (Sachs, '74).

Miss Bateson and Francis Darwin (88) used decapitated

flower-stalks of Plantago lanceolata and Brassica. oleracca and

found, after numerous experiments, that in both Plantago and

Brassica, the greatest curvature was made by the stems placed

horizontally, less curvature by those inclined more than 90

No gontributions from the Botanical Laboratory of the University of Michigan.

o. 5.

rri

78 THE AMERICAN NATURALIST. (VoL. XXXIX.

degrees, and least curvature in the stalks inclined less than 90

degrees.

Czapek ('95) took up the same line of experimentation as

Bateson and Darwin, considering also the point which the other

experimenters seem to have neglected, 7. e., the latent period of

curvature in the various angles of deviation. His purpose was

to determine at what angle of deviation it is possible to get the

largest angle of geotropic after-effect, *the maximum reaction,"

for equally long induction periods. To eliminate specific differ-

ences, a variety of plants was used: Lupinus, Faba vulgaris

(Vicia faba), Phaseolus, Pisum, and Zea seedling-roots, hypo-

cotyls of Helianthus, and matured internodes of Secale. The

general result of Czapek's experiments is given in the statement

that the extent of the angle of after-effect curvature increases

steadily from the normal vertical position, reaching a maximum

at about 45 degrees above the horizontal or 135 degrees from

the normal, in the case of roots; 45 degrees below the hori-

zontal or 135 degrees from the normal, in the case of stems ;

then falls from that point to the inversely vertical position, 180

degrees from the normal. The horizontal position is not, there-

fore, according to Czapek, the one in which the maximum

reaction takes place.

In spite of his attempts in numerous experiments, even arti-

ficially lengthened for the purpose of enlarging small time-

differences, Czapek could detect no noticeable difference, as to

time of beginning curvature, in stems inclined from 20 degrees

to 150 degrees, but in those inclined less than 20 degrees and

in those whose angles of deviation were between the optimum

for geotropic response and the inverted position, 180 degrees

deviation, found a very considerable delay in the beginning

of response.

Stone (: 00) experimented with dynamometers, measuring the

after-effects of geotropic stimulation and found that in grass-

nodes and in the roots of Micia faba, all experiments gave simi-

lar results, indicating the horizontal position as that of greatest

geotropic excitability. He further found the relationship between

nodes at oblique angles and those horizontal to be proportional

to the cosines of their angles.

No. 458.] GEOTROPIC RESPONSE IN STEMS. 79

Jost (:02), after making various experiments, agrees with

Stone in doubting the validity of Czapek's results.

Just as this paper was ready to send to the publisher, there

came to hand a preliminary report by Fitting (:04) in which the

author states, among other results, that by a method somewhat

similar to mine he has found the strongest geotropic effect when

orthotropic plant members were placed in the horizontal position,

that is, at 9o degrees from their position of equilibrium.

Because of this division of opinion, and since, in all cases, the

experimenters had been led to favor one of the two angles of

deviation, 90 degrees or 135 degrees, it seemed that other angles

might be neglected and the issue.drawn between these two.

The present paper reports the results of a series of experiments

made in the Botanical Laboratory of the University of Michi-

gan under the direction of Professor Newcombe for the purpose

of determining, in a considerable number of plants, at which of

these two angles of deviation stems show the stronger geotropic

response. Since the earlier work had dealt chiefly with seed-

ling-roots and hypocotyls, the unbranched stems of actively

growing young plants were selected as the material for use in

most of these experiments.

METHOD OF ALTERNATING STIMULATION.

The two general methods used we shall call the “ Alternating

Stimulation” and the “ After-effect” methods. It will be

noticed that each differs somewhat from the methods of earlier

workers. In all cases, except the first few experiments with

Chrysanthemum which were made in the greenhouse where the

plants were illuminated on all sides, the work was carried on in

a dark-room whose temperature ranged from 20° to 24 €. (18.57

C. in one case).

It is evident that an orthotropic plant stem, if equally stimu-

lated on opposite sides, will remain straight, but if unequally

stimulated on the opposite sides, will become curved, and by the

direction of its curvature indicate the stronger of the two

stimuli. Since it was believed that the response of stems

would be greater for stimulation in one of the two positions of

80 THE AMERICAN NATURALIST. | [Vor. XXXIX.

deviation in question than in the other, it was proposed to

incline the plants first 9o degrees from the normal vertical posi-

tion, then r35 degrees from the normal, but in the opposite

direction, and to alternate between these two positions giving

the same length of time and number of exposures in each, until

a decided curve should result.

A special frame, devised by Professor Newcombe, made it

possible to experiment with a considerable number of potted

plants at one time. This frame was furnished with a hinged

rack for holding the pots and this was so hung or supported .

that by turning it from one stop to another, through an arc of

225 degrees, the plants could be set first at an angle of 9o

degrees, on one side of the vertical position, then at an angle of

135 degrees on the opposite side, or vice versa, and could be

quickly and easily turned from one position to the other with a

minimum of jarring.

The stems of the young plants selected were first tied to

upright sticks or wires, leaving the upper, growing portions of

the axes free to curve, while the weight of the older parts of the

stems was supported to prevent all sagging when they were

turned out of their normal position. In the case of several

seedlings in one pot, all whose hypocotyls were not vertical were

cut away at the outset. The pots were then firmly wedged in

the frame, care being taken to keep the growing tips upright.

When all was in readiness, the frame and its rack were turned

so as to bring all the stems into one of the two positions

desired, and alternation was begun.

Experimentation.

Young plants of Chrysanthemum, Ageratum, Lavandula,

Fuchsia, Heliotropium, and Coleus were used in these experi-

ments; also seedlings of Linum usitatissimum, Raphanus sativus,

Brassica alba, and Helianthus annuus. The process of alterna-

tion was continued from 2 to 73 hours according to the sensitive-

ness of the plants. When a noticeable curve appeared after an

equal number of exposures in the two positions, the pots were

set upright again and the direction of the stems was carefully

noted.

No. 458.] GEOTROPIC RESPONSE IN STEMS. 81

The accompanying figure shows the frame turned on its side

to bring the set of young Chrysanthemum plants into the

upright position for observation at the close of one experiment.

Plants 1, 3, and 4, numbering from the front, show typical

curves. Other plants of the set gave equally good curves

which do not show distinctly in this view.

During alternation experiments, the frame stands on the base

Fic. r.— Plants in turning-frame. a, base; 4, hinge-line; c, stop.

a and the shelf hinged at 5 hangs vertically while exposing the

stems at 9o degrees from the normal position, then is turned

Over to stop c to make the exposure at 135 degrees from the

vertical.

After experimenting in this way for some time, it was thought

that an error might have entered through closing the experi-

ments immediately after exposing the plants in the last posi-

tion, thus allowing no time for the appearance of its resulting

curvature, and, in effect, giving less exposure in one of the

two positions than in the other. To remedy this, in the later

82 THE AMERICAN NATURALIST. (Vor. XXXIX.

experiments the plants were allowed to stand upright for half an

hour after the last exposure, before making the final observation.

In no case did this modify results in favor of the deviation of

135 degrees, while with few exceptions, the plants, after this

treatment, showed more pronounced curves in favor of the devi-

ation of 9o degrees than they did at the close of stimulation.

This was true whether alternation was begun from the position

of 90 degrees deviation or from that'of 135 degrees.

Marked differences in sensitiveness, indicated by the length of

time required to produce curvature, were shown not only by

plants of widely different genera but by different individuals of

the same species and by the same individual at different times.

Of the 395 plants used in these experiments, 53 did not

respond in the time given to the experiment, and are simply to

be considered less sensitive than their fellows showing curva-

ture. Of the 342 that did curve, 331 or 96.8 % responded bet-

ter for the deviation of 90 degrees, 11 or 3.2 % only, for the

deviation of 135 degrees.

Table I. Results Obtained by Alternating Stimulation.

Time | No Curvature at Deviation of

No. Material. Temp. | Hrs. Min. | vature. 9o degrees 135 degrees

Young plants.

6 | Chrysanthemum 2— o 3 3 9

6 " 139 C | 3— 20 2 4 o

5 " 189 C | 3— 20 I 4 2 slight o

5 " 219 C | 3 — 40 o 5 o

6 * 23°C| 3— o o 6 rslight o

10 X 22°C | 7—45 o 10 o

9 | Ageratum 20°C} s— o| o B o

5 | Heliotropium 222C| 4— o o 5 2veryslight | o

7 | Lavandula 239 C | 3 — 40 o 7 slight o

7 " :222C| 3— o o 7 o

3 " 222C| 2—40|. o 3. slight |o

10 | Fuchsia 25°C] 2— o o 10 o

10 “u 18°C} 2—40| 5!| 5 ud

9 " 20 C | 3 — 40 o 9 o

9 | Coleus 239C| 3— o o 7 2 very slight

2 " 229C] 240] o o 2 very slight

Seedlings.

8 | Linum 1 o

150 | Raphanus sativus | 24°C} 2— o 3 1248 2

"After standing upright 30 minutes, all were curved in favor of go degrees

deviation.

No. 458] | GEOTROPIC RESPONSE IN STEMS. 83

Table T.— Continued.

Time |Nocur- Curvature at Deviation of

No. Material. Temp. | Hrs. Min. | vature. degrees 135 degrees

291| Raphanus sativus | 222 C | 4— o 8 18 3 apparently

221 n B 21°C | 6— 30 7 14 I

311| Brassica alba 229C| 4— o 3 28 o

25% " " 21°C} 6—30| ıı 14 o

211| Helianthus annuus | 219 C | 6 — 30 7 13 I

395 53 133! it

Number showing curvature, 342

Percent of these showing curvature for deviation of 90 degrees, 96.8.

[73 [14 & [14 “ « “ & [23 135 « 32.

AFTER-EFFECT METHOD.

By this method, orthotropic plant members are exposed to the

one-sided action of gravitation by being placed out of their

normal position; but before a geotropic curve has time to

appear, the plant is put upon the klinostat and so revolved that

the further curving effect of gravitation is neutralized during the

revolution, Thus any geotropic influence induced in the plant

before the plant was placed on the klinostat has opportunity to

manifest itself. If, now, the gravitation effect on plants differs

according to the deviation of the plant from its normal position,

we may expect the size of the after-effect angle attained on the

klinostat to be greatest when the previous exposure of the plant

» was made at the angle of optimum stimulation. In other words,

this method may possibly be used to aid in the discovery of the

angle of optimum stimulation.

It was believed that results obtained by exposing stems for

the short period to the gravity-stimulus would be more reliable

than those of Czapek who forcibly prevented all curvature of

the roots and hypocotyls used while exposing them for hours to

the action of gravity in each of the two positions, and thus, it

would seem, making it possible for the long continuance of a

weak stimulus to equal the effect of a stimulus in reality

Stronger.

! Results quoted from Professor Newcombe by permission.

34 THE AMERICAN NATURALIST. [VOL. XXXIX.

Experimentatton.

The plants used in these experiments were prepared as in the

preceding series, then fixed on klinostats with stems radial to

the horizontal axes of rotation. One half of the number used

were inclined 9o degrees, the other half, 135 degrees from the

vertical, and both sets were held in position for a time somewhat

shorter than the previously determined latent period for geo-

tropic curvature in the species used. The subsequent influence

of gravity was then removed by rotation on the klinostats for a

time at least twice as long as the period of stimulation, and

finally, the pots were set upright and the amounts of curvature

made by the plants of the two groups were carefully compared.

The number of individuals, as well as the number of species

used in these experiments was smaller, and the results obtained

were less satisfactory than in the experiments by the method of

“alternating stimulation," but when any difference in after-

effects could be observed, it was in agreement with the results

of the alternation experiments. Ageratum, Lobelia, Chrysan-

themum, and the seedlings of Linum showed greater curvature

as the after-effect of stimulation at the angle of 90 degrees

from the normal position than at 135 degrees.

Table II. Results by After-effect Method.

Material. Temper- Latent Time of Time of Greater Curvature

ature. Period. Exposure. | Rotation. for Deviation of

Young plants.

Lobelia 25.59 C | 30 min. 20 min. | 40 min. 90 degrees

Ageratum 22.09 C | 20 “ ry * 40 ^ go ^

Chrysanthemum | 22.09 C | 30 “ +| 30 “ 60 * 90 ^

Seedlings.

Linum HSCs * +) dg" Codes go Oe?

No. 458.] GEOTROPIC RESPONSE IN STEMS. 85

CONCLUSIONS.

In conclusion it may be said that both the method of “ alter-

nating stimulation " and the *after-effect" method as I have

used them in numerous experiments involving a greater number

of species than other experimenters have reported, furnish

remarkably strong evidence that stems respond better to the

gravity stimulus when their angle of deviation from the normal

position is one of 90 degrees than when it is one of 135 degrees ;

and since the question seems to have been narrowed to these

two angles by earlier workers, it may further be claimed that the

angle of deviation from the normal vertical position at which

stems show the strongest geotropic response is one of 9o

degrees.

UNIVERSITY OF MICHIGAN.

BIBLIOGRAPHY.

BATESON, A. and Darwin, F.

'88. A Method of Studying Geotropism. Annals of Bot., II, 65.

CZAPEK, F.

'95. Untersuchungen über Geotropismus. Jahrb. Wiss. Bot., XXVII,

283.

FITTING, H.

:04. Geotropische Untersuchungen. (Vorl. Mittheil) Ber. Deutsch.

Bot. Gesellsch., XXII, 361. :

Jost, H.

:02. Die Perception der Schwerereizes in der Pflanze. Biol. Centralbl.,

XXII, 167.

SAcHs, J.

774. Ueber das Wachsthum der Haupt- und Nebenwurzeln. Arbeit.

Bot. Inst. Würz., I, 454

'82. Ueber orthotrope und plagiotrope Pflanzentheile. Arbeit. Bot. Inst.

Würz., II, 240.

'87. Lectures on the Physiology of Plants. English translation.

STONE, G. E.

:00. Geotropic Experiments. Bot. Gazette, XXIX, 136.

NOTE ON VARIATION IN THE RAY FLOWERS OF

RUDBECKIA.!

RAYMOND PEARL.

IN a recent number of this journal (Vol. XX XVIII, pp. 427-

429) Mr. F. C. Lucas has published an account of the variation

in the number of ray flowers in Rudbeckia hirta, the common

*brown-eyed Susan." Since attention has been called to the

matter in this way, it seems desirable to put on record some

statistics on variation in this form collected by the writer.

My material consisted of 430 heads from plants collected at

random from a large patch, July 25, 1903. The locality was

Farmington, N. H. The plants were growing in an open hay

field, on a moderately sloping hillside. The soil was a sandy

loam, and on account of the thorough drainage, the ground was

decidedly dry. In the counting I was assisted by Mr. Roswell

J. Pearl.

The following frequency distribution of ray flowers was

obtained :

Number of :

ray flowers. 6 9 8 910 JI HM 114 'S 16 17 18 19 20 21 22 23 24

Pay sopd eup Donare?

Total. 430

The frequency polygon is shown in Figure 1.

The mean number of ray flowers here is 11.365. The agree-

ment with Lucas’ Lot 4 is very close in all particulars except €x-

tent of range. This series gives peaks at the Fibonacci numbers

8 and 13, the principal one being at 13, as in his cases. In this

series, as in Lucas’ Lots 2, 3, 4 and 5, all the heads on each

plant collected were counted. It would appear from a compari-

! Contributions from the Zoölogical Laboratory, University of Michigan. No.

' 88 THE AMERICAN NATURALIST. | (Vor. XXXIX.

son of Lucas' Lot 1 with Lots 2 and 3 or 4 that this procedure

tends to give a decidedly lower mean than is obtained from a

random sampling of heads directly collected in the field.

A slight typographical error in the paper of Lucas to which

Frequency

HHE

ee | |

TUE

| 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

smi P E

Fic. r.— Frequency polygon. Ray flowers of Rudbeckia.

reference has been made, was noted. In the legend to Fig. 2

the number of heads in the combined Lots 2 and 3 is given

as 468, while in the text Lot 2 is stated to have included 225

heads, and Lot 3, 240 heads.

NOTES AND LITERATURE.

ZOÖLOGY.

The Halictine Bees of America.— Mr. J. Vachal has published

the descriptions of a large number of supposed new American bees

of the genus Halictus, in the Bulletin de la Société Scientifique,

Historique et Archéologique de la Corréze (France), July-Septem-

ber, 1904. As this publication is one not usually seen by American

naturalists, it will be useful to give a list of the species, with the loca-

lities and some indication of their characters. This information

follows herewith in tabular form. I have not thought it worth while,

at present, to give the characters of all the Mexican species; but

the table clearly separates all those of the United States.

Abdomen with bands of pale hair or tomentum on the zem esc of

the segments d

Abdomen with bee or lateral sache of. Bd. or tomentum at the bases

of the segments .

Abdomen without distinct odd or sio of eae hr or tomentum on the

apical margins or at the bases of the segments, but often more or

less covered with fine pubescence : ot a

- Species without metallic tints

At least the head or the thorax more or less metallic. with | green

tints í :

?. Very large, 14 mm. To (British Columbia) f ; PR d

Not over 11} mm,, allied to Æ. parallelus Say (Nevada)

denticulus d, 9.

3. Species of Georgia, New York, Pennsylvania, British Columbia, and

Illinois ; closely allied to Æ. zumulorum L. — . nearcticus, 9, d.

Species of South America

ochromerus, 9 (Brazil) and citricornis, TY Miel

4. Abdominal segments black or brown, the margins concolorous

. Abdominal segments with the bins borders more or less i CR or

reddish

Posterior face of N with a distinct, dum border; at = at

si es 6.

Posterior Pus of inch ibas without séh a den, the lateral mar px

rounded : : . 8.

—

THE AMERICAN NATURALIST. [Vor. XXXIX.

. Smaller, length not over 7 mm. (Mexico) . : : . linctus 9.

Larger, length 8 mm. or more ; females

Species of Mexico . Zrichecus, transvorsus, RE er an

Species of unknown origin, but closely allied to Æ. pacificus Ckll.,

with the size smaller; the enclosure of metathorax shorter, with

finer striz, etc. : : citerior.

. Species of Mexico . PON tricnicos, diis, SEHR pharus,

costalis, spinalis, and pallicornis, the last based on a d

Species of Britisb Columbia and ray State; 9 roj mm. long,

black : . egregius.

Species of Colorado ; d 7i mm. Aat bitk, the apical half of the

clypeus yellowish . . colatus.

Posterior face of metathorax with | a distinct share mar : IO.

Posterior face of metathorax with the lateral margins at least pariy

rounded ; ; i ; à ; i

. Females * i : : à i i = v

es : : ; , soc dis

. Smaller, length m iil 7 mm. (Mexico) i . respersus and laneus.

; noh

Largest, length 8-81 mm.; black South Coral, New York,

i crassus.

. Abdominal baois at habs of vd. I to 3 entire (Colatado)

. granosus.

Abdonddsl bands iduce, PER 2 d 3 having sus small grayish

spots on each side (Washington i doe : : . occultus.

. Legs black (Mexico ?) Pon en ur MEM

At least the tarsi partly yellow .

I5.

. Labrum black (California; a black species 8i mm. long palit.

16.

Labrum yellow or testaceous

Mandibles black, at least basally, never ve ` . Kk TA

Mandibles more or less spotted with yellow 19.

Anterior tibia without a yellow stripe ; tubercles and egin not

spotted with yellow (Colorado) . green

Anterior tibia "mes with ers tobetelés ad d tegul with a yellow

18.

spot

Larger, legi "di mm., u below ‘the antennae longer (British

olumbia) . arctous.

Smaller, length 7 mm. a oe Dich the antennae shores (California

ns.

« Tubercles dark ; on short, eyes converging below ; ie area of

metathorax acon semicircular, entirely N > irregular stri-

olæ ; length 7-71 mm. (Colorado) . : nigricollis.

1 H. crassus is said to differ from Æ. similis Sm., by its larger size, and the

smoky yellow tint of the wings, and from Æ. fulgidus Crawf., by the color of the

wings and the less punctured abdomen. :

No. 458.] NOTES AND LITERATURE. 9I

Tubercles, tegulz, and anterior tibia more or less tinged or marked

with yellow 20.

20. Length 6 mm. or e anterior tibia spoted with bon! : tb seer

segment of abdomen without an impression arco gularis.

Length 6} mm. or more . ; à i 4b

‘21. Species of Mexico . : ; ! aratus.

Species of Colorado; all the tibiae yellow : . gelidus.

22. Only the apical border of the abdominal segments pati | 23.

Abdomen almost entirely reddish ; 5 mm. long (Oaxaca, Meiioe)

i ; i í : i , ; curtulus.

25. ENS supposed to be Mexican ; black, wd small . bivarus, 9.

Species of Colorado, Nevada, and Vancouver I. ; about 6 mm. long,

shining black ; face long ; mesothorax and scutellum finely, densely

punctured ; enclosure of metathorax lunate, with fine, irregular,

indistinct strie; wings bronzy-hyaline, nervures yellow ; male with

labrum dark, alid jy ph brown, without yellow or testaceous mark-

ings : ; : : . diatretus El d^

24. Not niai :

At least the head or timi more or id BR ib

Posterior face of metathorax with a sharp border; Hack, Ment large ;

hind spur pale, with three sharp spines (Washington State) fartus, 9

Posterior face of metathorax with its lateral margins rounded, at least

above; black, head small; length, 9 64-7, d 6mm. (Mexico) sertus.

Species of South America

beskei (Brazil), autranellus (Buenos-Aires), pisinnus (Chile).

Species of unknown locality; d 7 mm. long, green : anifer.

Species of Mexico . ; 27.

27. Less than 7 mm. long i i ; bilali, In dui, end as

Over 7 mm. long ^ à ; . biseptus, ectypus, and coactilis.

T. D. A. COCKERELL.

Notes on Recent Fish Literature.— Mr. C. Tate Regan, of the

British Museum, continues his varied series of fish studies bya

number of short papers in the Annals and Magazine of Natural His-

tory. One of these, “The Phylogeny of the Teleostomi" (May,

1904), must challenge the attention of all palzontologists by its bold

theory that the chondrostean ganoids (Paleoniscum, Acipenser,

Polyodon, etc.) are the most primitive of teleostomous fishes, and

that they have given rise to the crossopterygians and dipnoans as

well as to the ostracophores, arthrodires, and teleosts. After sepa-

rating the still more primitive sharks, Mr. Regan divides the other

fishes into five orders, Chondrostei, Crossopterygii, Placodermi, Dip-

neusti, and Teleostei. The Teleostei | have sprung, in his scheme,

92 THE AMERICAN NATURALIST. (Vor: XXXIX.

from the chondrostean ganoids, through the holostean ganoids (Aspi-

dorhynchus, Lepisosteus, Amia, etc.) which he regards as teleosts.

On the other hand, the Crossopterygii, likewise descended from

Chondrostei, have given rise to Dipneusti (dipnoans) and also to

Placodermi. This latter group includes both Ostracophores and

Arthrodires. The Heterostraci are excluded from this group, being

regarded as armored sharks.

The fact that paleontology does not bear out this view is dis-

missed with the statement that these conclusions *are in accordance

with the morphological evidence, which is clearly and sufficiently

complete, whilst the geological record is and must be from the nature:

of the case very incomplete."

The close resemblance between the basal structures of the paired

and the unpaired fins in the Chinese Paddle-fish (Psephurus gladius)

is one of the important pieces of evidence in favor of the primitive

nature of the Chondrostei, and in favor of the origin of all fins alike

from folds of skin.

The conclusions of Mr. Regan are thus summed up:

1. The Chondrostei are the most generalized Teleostomi.

2. The Crossopterygii differ from them in the lobate pectoral fin

and in the larger paired gular plates.

3. The placoderms (Coccosteidæ, Asterolepidæ, Cephalaspidæ)

are a natural group not related to the Heterostraci, which are Chon-

dropterygii. They may probably be regarded as armored primitive |

Crossopterygii, this view being most in accordance with the arrange-

ment of the cranial roof bones in Coccosteus, the structure of the

ventral fin in Coccosteus, and the structure of the pectoral limb in

Asterolepidæ (which structure he regards as a true pectoral fin).

4. The Dipneusti probably originated from more specialized

Crossopterygii, e. g., from the neighborhood of the Holoptychidæ.

5. The Teleostei differ in so many respects from the Chondrostei

that they should rank as an order in which the Holostei are

included.

This view of the case is original and suggestive, but so far as the

major premise (No. ı above) is concerned, most naturalists will find

it unconvincing.

Mr. Regan discusses the genus Lichia of Cuvier, dividing it into

two genera, Lichia (Amia) and Campogramma Regan (V adigo).

Lichia glauca he refers to the genus Trachinotus. The gaff-top-sail

Pampano, also called Zrachinotus glaucus, a name of later date, is

deprived of its name by the intrusion into the same genus of an

No. 458.] NOTES AND LITERATURE. 93

earlier g/aucus. To this American species Regan gives the new name

of Trachynotus palometa. Porthmeus is a synonym of Lichia, while

Hypodis Rafinesque, not mentioned by Regan,is a synonym of

Trachinotus.

Regan re-describes Holocentrus osculus Poey, and describes Centro-

fomus argenteus, a new species, allied to C. ensiferus, from Barbadoes

and Guiana. C. mexicanus he regards as identical with Centropomus

parallelus.

The following new species are also described by Mr. Regan:

Clupea (Opisthonema) bulleri from Las Peñas in Jalisco; Zngraulis

argentivittatus from Las Peñas; Pseudoxiphophorus pauciradiatus

from Orizaba; Zoogoneticus maculatus from Rio Santiago;! Chara-

codon geddesi from Lake Tezcoco, Mexico; Heros octofasciatus from

British Honduras; Zeros callolepis from Santo Domingo de Guz-

man, Mexico; Pristigaster (Opisthopterus) effulgens from Ecuador;

Ophichthys (Pisodontophis) brevimanus from Ecuador; Piabucina

astrigata from Ecuador; Piabucina pleurotenia from Venezuela;

Trichomycterus vittatus from Peru; Trichomycterus retropinnis from

Colombia; Trichomycterus meride from Venezuela; Pimelodus

(Pimelodella) teniophorus from Matto Grosso; Pimelodus (Pimelo-

della) griseus from Ecuador; Haplochilus peruanus from Peru;

Belone (a Tylosurus) fluviatilis from Ecuador; Centropomus atridor-

salis from Ecuador; Corvina (a Sciena) crawfordi from Montevideo ;

- Acara saparensis from Ecuador; Gobius (Awaous) guentheri from

Ecuador;? Chasmodes maculipinna from Ecuador; Chetodon dixoni

from the New Hebrides; Draconetta acanthopoma from the deep

waters of the North Atlantic.

Draconetta is considered by Mr. Regan, probably correctly, as an

ally of Harpagifer. The nominal family of Draconettidz is there-

fore not to be separated from the Harpagiferidz, and is a close ally

of the Nototheniide.

A considerable collection made at Rio Janeiro by Dr. Geeldi is

the subject of an important paper. The following are the chief

additions :

` Raia cyclophora new species; Murena helena a Mediterranean

! Fundulus labialis and. F. guatamalensis are probably not species of Zoogen-

eticus as has been suggested by Dr. Meek. :

* Gobius latus O’ Shaughnessy is not identical with G. favus nor with G. banana.

Gobius or Awaous banana, the West Indian species, should not be identified with

Gobius (Awaous) taiasica, a Brazilian species which is probably the same as

Awaous latus.

94 THE AMERICAN NATURALIST. (Vou. XXXIX.

species now recorded from Brazil; Atherinichthys salle for a new

species of Menidia from Mexico; Serranus flaviventris should

include S. dispilurus, S. subligarius, and S. brasilienis. It is distinct

from S. auriga. Diagramma geldii is identical with Genypterus

cavifrons, for which species Mr. Regan does not accept the older but

somewhat doubtful name, /uteus. Mylacrodon geldii is a new genus

allied to Pomadasis but with some molar-like teeth.

The Old World genera, Gazza and Leiognathus, are referred to

the Gerrid&, from which they differ in the small scales and in hav-

ing the gill membranes narrowly united to the isthmus. Regan gives

an analysis of the striped species of true Gerres he regards as ten-

able, viz., brevimanus, plumieri, mexicanus, lineatus (including brasil-

ianus and embryx of the Atlantic coast), axillaris, and patao. G.

brasilianus is, however, not the same as G. /ineatus.

Pristedion altipinnis new species; Oligoplites saliens (with four

dorsal spines) is a valid species, as are also O. palometa, altus, saurus,

and mundus. ;

Not knowing the species of Spanish Mackerel, called Scombero-

morus regalis, Regan identifies it with S. maculatus. The fishermen

know better. Scomberomorus immaculatus from San Domingo is not

identical with S. cavala.

Genypterus brasiliensis, new species ; Achirus fonsecensis is recorded

for the first time from the Atlantic and Lophius piscatorius for the

first time from Brazil.

In 1900, the “ Albatross” made a short dredging cruise on the

coast of Japan, taking 111 species of fishes. Of these, 58 were new

to science and have been described by President Jordan and his

associates. In a paper in the Bulletin of the United States Fish

Commission for 1903, figures of all these new species are given, with

references, notes, and descriptions of a number of new species. This

memoir is by Jordan and Starks. With it is included a monographic

review of the Macrouride, or Grenadier-fishes of Japan, by Jordan

and Gilbert, with figures of most of the numerous species.

The most important faunal work in ichthyology for the year is the

account of the Fishes of Panama Bay by Professor Charles H.

Gilbert and Mr. Edwin C. Starks, published by the California

Academy of Sciences (Mem., Vol. 4), and reprinted by the Hopkins

Seaside Laboratory of Stanford University.

This paper contains a very full account of the fishes of Panama,

No. 458.] NOTES AND LITERATURE. | 95

374 in all, with excellent plates, the work of Mrs. Chloe Lesley

Starks, representing most of the new forms. The descriptions are

prepared with that minute attention to accuracy characteristic of all

of Dr. Gilbert’s work. Of the many new species, the majority were

included in the appendix to Jordan and Evermann’s fishes of North

America. Those not so included are the following:

Galeichthys eigenmanni, Tachysurus evermanni, Fistularia corneta,

Oligoplites refulgens, Peprilus snyderi, Sagenichthys (properly Macro-

dom) mordax, Pomacentrus gilli, Halicheres macgregori, Balistes

verres, Xesurus hopkinsi, Guentheridia, a new genus of Tetra-

odontide (formosa), Prionotus ruscarius, Microgobius miraflorensis,

Evermannia panamensis, Batrachoidea boulengeri, Porichthys greenet,

Hypsoblennius piersoni. Lythrulon opalescens is not distinguishable

from Z. flaviguttatum, and Menticirrus simus is identical with M.

nasus. Eleotris equideus cannot be separated from E. pictus, and

Microgobius cyclolepis is the same as M. emblematicus. Ancylopsetta

sabanensis is identical with A. dendritica, and the genus Ramularia

is not tenable. Solea fischeri and Solea panamensis are synonyms

of Achirus fonsecensis.

The following conclusion as to the relations of the fish faunas on

the two sides of the isthmus of Panama is of special interest. “ The

ichthyological evidence is overwhelmingly in favor of the existence of

a former open communication between the two oceans, which must

have become closed at a period sufficiently remote from the present

to have permitted the specific differentiation of a very large majority

of the forms involved. That this differentiation progressed at

widely varying rates in different instances becomes at once apparent.

A small minority of the species remains wholly unchanged, so far as

we have been able to determine that point. A large number have

become distinguished from their representatives of the opposite coast

by minute (but not ‘trivial ’) differences, which are wholly constant.

From such ‘representative forms,’ we pass by imperceptible grada-

tion to species much more widely separated, whose immediate rela-

tion in the past we cannot confidently affirm. Of identical species,

occurring in both oceans, our Panama list contains 43.

“ The total number of identical species which we recognize in the

two faunas now separated by the Isthmus is therefore 54, as compared

with the 71 enumerated by Jordan (1885). It is obvious, however,

that the striking resemblances between the two faunas are shown as

well by slightly divergent as by identical species, and the evidence in

favor of interoceanic connection is not weakened by an increase in

96 THE AMERICAN NATURALIST. (VoL. XXXIX.

one list at the expense of the other. All evidence concurs in fixing

the date of that connection at some time prior to the Pleistocene,

probably in the early Miocene. When geological data shall be ade-

quate definitely to determine that date, it will give us the best known

measure of the rate of evolution in fishes.

Of the 82 families of fishes represented at Panama, all but 3

(Cerdalidz, Cirrhitide and Nematistiida) occur also on the Atlantic

side of. Central America; while of the 218 genera of our Panama

list, no fewer than 170 are common to both oceans. The well

developed families Centropomida and Dactyloscopidz are peculiar

to the tropical faunas now separated by the Isthmus of Panama."

In the Journal? of the Academy of Natural Sciences at Philadelphia

(Vol. 12), Mr. Henry W. Fowler has a valuable report on the fishes

collected in Sumatra by Harrison and Heller; 248 species are

embraced in this collection. This includes a number of new species.

'This paper contains notes on the little known forms, with excellent

plates of many of them. The paper will be of great value in the

study of the East Indian fauna. Several new subgenera are pro-

posed. Deveximentum is a new genus allied to Leiognathus, based

on Z. insidiator; the same species is the type of the earlier name

Equula.

In the Proceedings of the California Academy of Sciences, Vol. 3,

series 3, the late Cloudsley Rutter records a few fishes from the Gulf

of California. He unites the genus Villarius with Ictalurus and

describes a new Eleotrid Goby under the name of Pycnomma semis-

quamatum. ‘The genus is certainly close to the imperfectly known

genus Gymneleotris. A new description of Em/emaria oculocirris is

given.

In the same Proceedings Dr. Charles H. Gilbert has notes and

descriptions of fishes of the Pacific. Ne/uma mazatlana, new species,

from Mazatlan; Nemichthys avocetta, which is properly the same as

N. scolopaceus; Schedophilus heathi, new species, from Monterey ;

Xeneretmus infraspinatus, new species, from Cape Flattery. Cleve-

Jandia rose is identical with Clevelandia ios; Rathbunella alleni, new

species, from Monterey; Auchenopterus mexicanus, new species, from

La Paz.

1 The supposed character of the dorsal rays in Nemichthys So it

from other eels is fallacious, being produced by the drying of the specime

No. 458.) NOTES AND LITERATURE. 97

In the Report of the Illinois Fish Commission for 1902, Mr.

Thomas Large gives a useful list of the fishes of Illinois, with

analytical keys and notes on the different species.

In the Proceedings of the U. S. National Museum (Vol. 27)

Jordan and Snyder describe new species of fishes from Hawaii as

follows: Brachysomophis henshawi, Ariomma lurida, Lactoria

schlemmeri, Antennarius laysanius, and Apogon evermanni. A num-

ber of other species are added to the fauna of theislands. Ariomma

is a new genus, apparently allied to Apogon.

In the Proceedings of the Biological Society of Washington (Vol.

17) Dr. H. M. Smith describes a small eel found in the deep

waters south of Nomans Land. Itis entirely black and with the

eyes wholly hidden. Otherwise it is quite similar to the common eel.

Dr. Smith calls it Anguilla ceca.

In the Zroceedings of the Scientific Society of Christiania for

1904, Dr. Collett describes four new species of deep-sea fishes

from the Faro& Islands. These are Ætmopterus princeps, Pris-

tiurus murinus, Chimera mirabilis, and Halargyreus affinis. The

Chimæra is made the type of a new subgenus called Bathyalopex,

‘having the anal united with the caudal. The Japanese species

mitsukurii would belong to this group, which is, however, scarcely

entitled to distinctive rank.

In the Bulletin of the Museum of Comparative Zoölogy at Har-

vard College (Vol. 46, No. ı) Dr. Eastman gives a very inter-

esting account of the history of the fish collections from Monte

Bolca in Tuscany. A fine collection of these fishes is now in the

Museum of Comparative Zoölogy. Dr. Eastman gives the synonymy

of the principal species in this collection, with descriptions and fig-

ures of the most important species. The new generic name Histio-

notophorus is proposed for a Lophioid form and a new species of

Pygzus, P. agassizi, is described and figured. The species called

Symphodus szajnoche doubtless represents a new genus of Labridz,

and the so-called Caranx primevus should also represent a new

genus even more Trachurus-like than Trachurus itself.

In the American Journal of Science (Vol. 18, No. 104), Dr.

Eastman discusses theappendages of Asterolepis. He regards these

paddles as not homologous with the pectoral fins of the true fishes,

his view being opposed to that recently put forth by Mr. Regan. `

98 THE AMERICAN NATURALIST. (Vor. XXXIX.

In the Journal of the College of Science of Tokyo (Vol. 19) Dr.

Bashford Dean gives an elaborate account of the anatomy of the

long-snouted Chimzera of Japan, RAinochimera pacifica.

In the Journal of the College of Science at Tokyo, Dr. Bashford

Dean discusses the hag-fishes, or Myxinoids, of Japan, describing a

new genus, Paramyxine atami, and a new species, Homea okinoseana.

He also adds notes on Homea burgeri and Myxine garmani, with an

analysis of the species of the genus, which he calls Homea, but

which must stand under the less satisfactory but earlier name of

Eptatretus. In the same Journal Dr. Dean has notes on the Chi-

mzras of Japan, giving a full account with excellent plates of

Chimera mitsukurii and C. phantasma. ‘Yhe distinction between

these two species was recognized almost simultaneously by Jordan

and Snyder, who adopted the name “mitsukurii” proposed by Dr.

Dean in correspondence.

Dr. Léon Vaillant in the Comptes Rendus for 1904 gives an inter-

esting account of the Japanese goblin shark, Mitsukurina owstont,

of which a specimen about seven feet long has been received by the

Museum at Paris. Dr. Vaillant puts the species in the family of

Lamnidz with Odontaspis and other related forms.

In the Bulletin of the Museum at Paris for 1903, Dr. Vaillant

gives an account of the hatching of eggs in the branchial cavity in

the species of Apogon-like fish, called Cheilodipterus affinis, at Mar-

tinique.

In the same Buletin, Dr. Vaillant and Dr. Pellegrin give new

descriptions of the species of Tetragonopterus, very briefly and

unrecognizably mentioned in 1868 by Dr. M. F. Bocourt in the Bul

letin of the Société Zoölogique de France. Dr. Pellegrin also gives

an account of fishes collected on the coast of Chile.

In the Records of the Australian Museum (Vol. 5, No. 4), Mr.

Edgar R. Waite gives a valuable account of rare fishes lately taken

on the coast of eastern Australia. He shows that the genus

Goodella is the larval form of Trachinocephalus. The identity of

the Japanese genus Iso with the Australian Tropidostethus is also

indicated; but Mr. Waite overlooks the fact that the latter name is

preoccupied, and the genus may still remain Iso.

No. 458.] NOTES AND LITERATURE. 99

In the Zoologischer Anzeiger (Vol. 27, No. 22), Dr. L. S. Berg

describes a new genus of sturgeons which he calls Huso, the type

being Acipenser huso. This differs from the other sturgeons in hav-

ing the gill membranes united, forming a free fold across theisthmus.

The snout is soft and flexible and the very large mouth includes the

whole under surface of the snout. The barbels are compressed.

This definition is a new one, but the generic name Huso was used

by Brandt and Ratzeburg in 1883 for a subgenus including the same

type.

Under the title of “ Pescas do Annie," Dr. Alipio de Miranda

Ribeiro gives an account of fishes taken by the Steamer “ Annie? off

the coast of Brazil with the “otter trawl.” Fifty-nine species were

obtained. "These areillustrated by means of photographs. Among

‘the new species are Fistularia rubra, Anthias duplicidentatus, Liocsa-

cus intermedius, Pontinus corallinus, Peristedion roseum, Pseudopercis

numida, Hypsicometes heterurus, Lepophidium fluminense, Urophycis

mystaceus, U. latus, Paralichthys triocellatus, and Gymnachirus zebri-

nus.

In Sports Afield for August, 1904, Dr. Barton W. Evermann gives

valuable suggestions as to how to study a lake. This has particular

reference to training children and young students to learn how to

weigh evidence. Dr. Evermann calls attention to the fact that most

. of the so-called “bottomless ” lakes are from 4o to 60 feet deep.

In the Bulletin of the U. S. Fish Commission for 1904 Dr.

Jordan gives an account of fishes collected by Dr. Joseph C.

Thompson on the Tortugas, with the descriptions of several species,

four of them new, vis. :— Cfenogobius toríuge, Gnatholepis thompsont,

Elacatinus oceanops, and Ericteis &alishere. A new genus, Acteis, is

proposed for the small blenny called Malacoctenus moorei.

Under the title of “The Fresh-water Fishes of Mexico north of the

Isthmus of Tehuantepec,” the Field Columbian Museum publishes

a moŝt valuable faunal monograph by Dr. Seth Eugene Meek. it

represents the results of two expeditions to Mexico, together with

the examination of all previous papers on the fish fauna of that

region. Two hundred and twenty-seven species are described, 28

of them being new, with three new genera. Excellent plates of

these species and many others are given, with a map of Mexico, and

IOO THE AMERICAN NATURALIST. | [Vor. XXXIX.

a very illuminating discussion of the faunal regions into which Mex-

ico is divided. .

The new genera are Cynodonichthys, allied to Fundulus, but with

large canines, Paragambusia, and Thorichthys, the latter related to

Cichlasoma. Dr. Meek recognizes four distinct fish faunas in Mexico.

One of these in the northeast is composed largely of migrants from

the north, as Carpiodes, Ictalurus, Lepisosteus. Another is made

up of migrants from the south, as Rhamdia, Cichlasoma, etc. The

third region includes the valley of the Rio Grande de Santiago, in-

cluding the now isolated lakes about the city of Mexico. This in-

cludes most of the characteristic Mexican types as Chirostoma,

Goodea, Aztecula, Evarra, etc. Very many species in this region are

viviparous. The genus Chirostoma stands out as almost the only

case among fishes where numerous closely related species inhabit

exactly the same waters. In the large lake of Chapala, there are

eight closely allied representatives of this type, all taken in the same

nets, and all alike known in the markets as the “Pescado blanco,”

noted for its delicate flavor. ‘These species are Chirostoma chapale,

grandocule, promelas, sphyrena, lucius, lerme, ocotlane, and estor.

In several other lakes, other species occur in similar assemblages.

But one species of Chirostoma is known outside the Lerma-Santiago

fauna. In almost every other case among fishes, where two closely

related species occur, they are not in the same waters, but in neigh-

boring waters. This indicates that almost all species of fishes have

originated through geographical isolation. Possibly the forms of

Chirostoma may have come into existence as mutations or saltations.

In no other case in ichthyology is this theory equally plausible. The

fourth faunal basin of Mexico includes the large river Balsas, flowing

southward, and containing but few kinds of fishes. The most notable

is a very large cat-fish peculiar to this basin, constituting the genus

Istlarius.

In the Bulletin of the Illinois State Laboratory of Natural History

(March, 1904), Mr. R. E. Richardson gives a monographic review of

the sun-fishes (Lepomis and Eupomotis) found in Illinois. He places

euryorus in the genus Lepomis, and recognizes two species (gibbosus

and Zeros) under Eupomotis. Apomotis Mr. Richardson unites with

Lepomis.

Otaki and Fujita have published two more folios of their “ Fishes

of Japan,” (Tokyo, 1904.) with Japanese text, and large colored plates

well executed, but of a size inconvenient for binding.

No. 458.) NOTES AND LITERATURE. IOI

In the Report of the Government Biologist of the Cape of Good

Hope for 1903, Dr. J. D. F. Gilchrist describes seventeen new species

of fishes from that region. One new genus, Cyttosoma, allied to

Cyttus, is also recorded.

In Vol. II of the Results of the Danish Ingolf Expedition, Dr.

Adolf Severin Jensen gives an elaborate account of the Lycodinz of

North Europe and Greenland, with a series of excellent plates. The

genus Lycodalepis is united by Jensen with Lycodes. ‘The species

generally receive better definitions than have been given by any previ-

ous author.

Dr. Gill discusses in the Proceedings of the United States National

Museum for 1904 the relations of the family of Ammodytida. In

view of the discovery of the Ammodytoid genus Embolichthys, with

jugular ventrals, these fins being wanting in all previously known

species, the group belongs among the jugular fishes. Dr. Gill finds

no relative nearer than the Hemerocoetidz.

In the Biological Bulletin for October, 1904, Mr. Edwin C. Starks

discusses the osteology of the fishes of the order or suborder Haplomi.

He finds it a heterogeneous group, including probably varying lines

of descent, having the bond of union of abdominal ventral fins, no

fin spines, and the loss of the mesocoracoid and orbitosphenoid

characteristic of more primitive fishes. :

In the Revista Chilena de Historia Natural, for 1904, Dr. Carlos

E. Porter describes some new fishes from the deep seas of Chile.

In the Zransactions of the Zoölogical Society of London, for

1904, Mr. C. Tate Regan gives a voluminous and important mono-

graph of the mailed cat-fishes of the South American fauna known

as Loricariide.

Dr. Joseph Schmitt publishes in Paris a valuable Monographie de

"Ile Anticosti, with a list of its animals, about 25 common fishes

being included.

Proceedings of the U. S. National

Jordan and Snyder describe in the I

a new fish from Hawaii.

Museum for 1904, Apogon evermanni,

D. S. .

102 THE AMERICAN NATURALIST. (VoL. XXXIX.

BOTANY.

Silviculture.‘—Silviculturists and others interested in forest

management will welcome the second part of Professor Mouillefert’s

comprehensive treatise which is now out. The first part havingc on-

sidered in much detail from the forester’s point of view the most

important tree species, this second part deals especially with the

management and exploitation of trees in assemblages or forests.

After defining precisely the terms used, the author considers most

comprehensively the principal methods of developing and harvesting

the two forms of wood, high forest and coppice, and the application

of these methods to the principal species of trees; gives advice as

to what to seek in any given case, and describes the nature and

amount of the product to be obtained, giving volume curves, direc-

tions for developing a forest working plan, calculations of annual

revenue, and so on. Special chapters deal with the cultivation of

osiers for the draining of soils and with the culture of truffles. The

chief modes of cropping and marketing forest products are also

taken up.

While special parts, such as rules for forest management and the

tables of annual returns, are based upon conditions different from

our own (it being possible by reason of the centuries of forestry

practice in France to lay down rules of practice and estimate yields

much more definitely than with us) nevertheless the general aspects

of the subject, the principles of the science and art of silviculture

are set forth so clearly and simply that the book is bound to be of

general interest to foresters and students of forestry in this country.

It will be particularly helpful in making clear to many certain sides

of the subject, such as the mathematics of forest measurements,

which, as they are often set forth in works on forestry, are not likely

to be easily understood.

C. S.»

Notes. — Loeb's St. Louis address on the recent development of

biology is printed in Science of December gth.

An important addition to the rather abundant recent literature of

apogamy is made by Strasburger, in a study of Alchemilla published

in the opening number of Vol. 41 of the Jahrbücher für wissen-

schaftliche Botanik.

! Mouiilefert, P. 7vai/é de Sylviculture — Part 2 — Exploitation et A ménagement

es Bois. Paris, Alcan. 1904. 12mo, 476 pp., 10 pls. 97 figs.

No. 458.) NOTES AND LITERATURE. 103

An account of the “blaze-currents” of vegetable tissues, by Wal-

ler, forms part of Vol. 37, Ne. 257, of the Journal of the Linnean

Society, Botany.

A paper on the absorption of electro-magnetic waves by living

vegetable organisms, by Squier, has been reprinted from General

MacArthur’s Report to the War Department on the Military Manceu-

vres in the Pacific Division, 1904.

A considerable discussion of the use of copper for the treatment of

polluted drinking water is contained in the American Journal of Phar-

macy for December.

The “summer-fall” of the leaves of Canary Island plants forms

the subject of a note by Vahl in Heft 2 of the Botanisk Tidsskrift

for 1904.

An interesting study of sandal seedlings is published by Barber

in Zhe Indian Forester for December.

Papers on myrmecophilous plants by Morteo and Villani are con-

tained in Vol. 18, Fascicle 10-12 of Ma/igZia.

Methods of surveying vegetation on a large scale are discussed

with illustrative diagrams, by Oliver and Tansley in Zhe New Phytol-

ogist of December 20.

Certain traumatic floral anomalies, and their heredity, are discussed

by Blaringhem in the Bulletin of the Muséum d'Histoire Naturelle of

Paris, 19o4, No. 6.

A paper on the structure of the starch grain, by Denniston, has

been separately issued from Vol. 14 of the Transactions of the Wis-

consin Academy of Sciences.

An anatomical study of Anemiopsis californica is published by

Holm in Zhe American Journal of Science for January.

A paper by Drabble on the anatomy of the roots of palms forms

Vol. 6, Part 10, of the current botanical series of Transactions of the

Linnean Society of London.

An interesting presentation of some of Burbank's experiments is

given by Jordan in Popular Science Monthly for January.

A progress report on the strength of structural timber, by Hatt, `

forms Circular No. 32 of the Bureau of Forestry, U. S. Department

of Agriculture. :

104 THE AMERICAN NATURALIST. | [Vor. XXXIX.

A further study of the “popping” of Indian corn, by Professor

Storer, is contained in Vol. 3, Part 4 of the Buletin of the Bussey

Institution.

Heckel publishes‘a paper on Solanum commersoni and its variations

as bearing on the origin of the cultivated potato in the Revue Hort-

cole of Marseilles for November.

The banana in Hawaii forms the subject of Bulletin No. 7 of the

Hawaii Agricultural Experiment Station, by Higgins.

Bulletin No. 88 of the Bureau of Chemistry, U. S. Department of

Agriculture, is devoted to the chemical composition of apples and

cider.

A paper on California olive oil, by Shaw, forms Bulletin No. 158

of the Agricultural Experiment Station of that State.

Some nature-photograms of cross-sections of wood are published

by Russell in the Gardeners’ Chronicle of November 26.

An ecological study of Brush Lake, by Schaffner, Jennings, and

Tyler, forms Vol. 4, Part 4, of the Proceedings of the Ohio State

Academy of Science.

A “Pugillus Cryptogamarum Canadensium,” by Cufino, is pub-

lished in Malpighia, Vol. 18, Fascicle 10-12.

Under the title “ Bouquet de Fleurs de Chine,” Léveillé publishes

a number of new Chinese species in Vol. 39, Fascicle 4, of the Bule-

tin de la Société d’Agriculture, Sciences et Arts de la Sarthe.

A second paper on new or noteworthy Philippine plants, by Mer- >

rill, forms [Buletin] No. r7 of the Bureau of Government Labora-

tories of the islands, dated October 1, 1904.

Part 10 of Koorders and Valeton’s “ Additamenta ad Cognitionem

Flore arborex Javanice” forms No. 68 of the Mededeelingen nit

's Lands Plantentuin.

The flora of western Australia is receiving important treatment

by Diels and Pritzel in current numbers of Engler's Botanische

Jahrbücher.

Vol. 4 of the “ Flora of Tropical Africa,” edited by Sir William T.

Thiselton-Dyer, has recently been completed.

Several additional species of Eschscholtzia are described by Fedde

in No. 35 of the WVotizblatt ef the Berlin Garden.

No. 458.] NOTES AND LITERATURE. 105

A number of new species of cacti are described from the notes of

the late Dr. Weber, by Gosselin, in No. 6 of the Bulletin of the

Museum d’Histoire Naturelle of Paris for 1904.

An attractive book, “ Abbildungen der in Deutschland und den

angrenzenden Gebieten vorkommenden Grundformen der Orchideen-

Arten,” by Müller, with descriptive text by Kränzlin, has been

issued by R. Friedländer & Sohn, of Berlin.

Some interesting test-tube cultures of orchids are detailed by

Bernard in the Revue Générale de Botanique of Nov. 15.

A revision of Tradescantia, as known from Texas, is published

by Bush in Vol. r4, No. 7, of the Zransactions of the Academy of

Science of St. Louis.

The prothallium of Ophioglossum vulgatum. is described by Bruck-

mann in the Botanische Zeitung of December 15.

Regneilidium diphyllum, the type of a new genus of Marsiliacez,

from Brazil, is described and figured by Lindman in Vol. 3 of

Arkiv för Botanik.

An important paper on Cyanophycez, by Zacharias, is separately

printed from Vol. 21 of the Jahrbuch der Hamburgischen wissenschaft

lichen Anstalten.

The first part of a historical review of the origin of species by muta-

tion is contributed by Harris to Zhe Monist of October.

An important paper by Goebel on cleistogamous flowers and the

adaptation theories is begun in the Biologisches Centralblatt of

November.

The summer activity of some spring flowers is discussed by Dr.

Keller in Part 2 of the current volume of Proceedings of the Academy

of Natural Sciences of Philadelphia. é

A paper on the origin and nature of color in plants, by Kraemer,

is contained in the Proceedings of the American Philosophical Society,

No. 177. :

Country Life in America for December contains striking pictures

of Anemone patens nuttalliana blooming in the snow.

A lecture by Haberlandt on the sense organs of plants is being

Published in current numbers of the Naturwissenschaftliche Rund-

SCHAU

106 THE AMERICAN NATURALIST. (Vor. XXXIX.

A treatise on the transpiration of plants, by Burgerstein, has

recently been issued from the press of Gustav Fischer of Jena.

Bower's St. Louis address, dealing with the relation of the axis to

the leaf in vascular plants, is printed in Science of October 21.

Coulter's St. Louis address on the development of morphological

conceptions is printed in Sczence of November 11th.

A paper on cytological technique, by Osterhaut, forms Vol. 2, No. .

11 of the botanical series of University of California Publications.

The comparative age of the different floristic elements of eastern

North America is discussed by Harshberger in a separate from the

August Proceedings of the Academy of Natural Sciences of Philadel-

phia. i

Westgate gives an account of the reclamation of the Cape Cod

sand dunes in Bulletin No. 65 of the Bureau of Plant Industry of the

U. S. Department of Agriculture.

Certain plants of the north temperate zone are contrasted with

their representatives in the high mountains of tropical Africa by

Engler in the Annals of Botany for October.

The second section of Volume 4 of the “ Flora Capensis,” covering

Hydrophyllaceæ to Pedalineæ, has recently been completed, with

index, under the editorship of the Director of the Kew Gardens.

An interesting paper on the forest flora of the Jubbulpore district

of India is published by Hole in Zhe Zndian Forester of November.

The botanical zones of the Madeiras are discussed by Menezes

in Vol. 8 of the Annaes de Sciencias Naturaes of Oporto.

An account of Liguidambar styraciflua is contributed to Nos. 8

and 9 of the current volume of Anales del Museo Nacional de Mexico,

by Alcocer.

De Vries’ Trifolium pratense quinguefolium is discussed by Tam-

mes in the Botanische Zeitung, Abt. 1, of November 15.

An account of the group of peaches known as honey-peaches is

given by Reimer in Bulletin No. 73 of the Florida Agricultural

Experiment Station.

An illustrated monograph of the willows of France, with classifica-

tion of the other European species, by A. and E. G. Camus, has

been published from the office of the Journal de Botanique, of Paris.

No. 458.] NOTES AND LITERATURE. . 107

Urbina gives an account of Pedilanthus aphyllus in the Boletín del

Museo Nacional de México of March last.

In the Gardeners’ Chronicle of Nov. 5 is given, by Müller, the first

partial description of some of Sprenger's hybrid Yuccas.

An account of the tight-chaffed wheats, “emmer ” and “spelt,” by

Saunders, forms Bulletin No. 45 of the Central Experimental Farm,

of Ottawa, Canada.

A neatly illustrated handbook of “New England Ferns and their

Common Allies,” by Helen Eastman, has been issued from The

Riverside Press of Cambridge.

315 Pteridophytes, of which a number are new, are noted for

Isthmian America by Hieronymus in Engler’s Botanische Jahrbücher

of October 25.

A monograph of North American Ustilaginez, by Clinton, forming

No. 57 of the “Contributions from the Cryptogamic Laboratory of

Harvard University," is published as Vol. 31, No. 9, of the Proceed-

ings of the Boston Society of Natural History.

Arsenic in papers and fabrics, and the so-called arseno-molds

belonging to the genera Aspergillus, Penicillium, and Mucor, are dis-

cussed by Haywood and Warren in Bulletin No. 86 of the Bureau of

Chemistry, U. S. Department of Agriculture.

Sydow's “Monographia Uredinearum," in fascicle 5 reaches the

end of Puccinia, of which 1231 species are recognized. The con-

tents of the volume are rendered accessible by good indexes.

A paper on Mexican Uredinex, by Holway, is contained in

Annales Mycologici for September.

Colletotrichum gleosporioides, and its attacks on the pomelo,

form the subject. of Bulletin No. 74 of the Florida Agricultural

Experimental Station, by Hume.

Papers on Middleton Fungi— by Gates, and Fungi of Nova Scotia,

a provisional list— by MacKay, have been separately issued from

‚the Proceedings and Transactions of the Novia Scotian Institute of

Science, Vol. rr.

Petri discusses the diagnostic value of the capillitium of Tylostoma

in Annales Mycologici for September. :

A third edition of Frost’s “Laboratory Guide in Elementary

108 THE AMERICAN NATURALIST. (Vor. XXXIX.

Bacteriology” has been issued from the Macmillan press, and,

gives a most serviceable foundation for a year's work.

An interesting article on invisible micro-organisms, by Dorset, is

reprinted from the Zwentieth Annual Report of the Bureau of Animal

Industry, U. S. Department of Agriculture.

Volume 1 of Ward's “Trees: a Handbook of Forest Botany for

the Woodlands and the Laboratory" (Cambridge, the University

Press, 1904) deals with buds and twigs, and constitutes one of the

best of the winter manuals yet published. In the second part of the

volume, keys, figures, and descriptions facilitate the determination of

British species. "

An annotated account of trees and shrubs tested in Manitoba and

the Northwest Territories, by Saunders, forms Bulletin No. 47 of the

Central Experimental Farm, at Ottawa, Canada.

In Nature of November 24, Mr. H. Charlton Bastian has again

taken up the question of heterogenesis.

A contribution to the study of fermentation, by Twight and Ash

forms Bulletin No. 159 of the Agricultural Experiment Station of

California.

An elaborate monograph of Hungarian Gasteromycetes, by Hollós,

has been issued in German translation from the Weigel Press of

Leipzig. :

A characteristic colored plate of Amanita muscaria is given in

The American Botanist of October.

A good “fairy-ring,” apparently of Agaricus arvensis, is figured in

The American Inventor of January 1, 1905.

Bulletin No. 75 of the Florida Agricultural Experiment Station is

devoted to a discussion of potato diseases, by Hume.

A new catalogue of the plants cultivated in the botanical garden at

Buitenzorg, by Hochreutiner, is begun in Bulletin de Institut Botan-

ique de Buitenzorg, No. 19.

An account of the cuitivation of Papaver somniferum, and the pro-

duction of opium, in the United States is given by Richtmann in the

Pharmaceutical Review of November.

A study of the chemical composition of some tropical fruits and

their products, by Chace, Tolman, and Munson, forms Bulletin No.

87 of the Bureau of Chemistry, U. S. Department of Agriculture.

No. 458.] NOTES AND LITERAIURE. 109

. A popular account of Christmas fruits and their sources is pub-

lished by McFarland in Country Life in America for December.

Southern evergreens and their commercial utilization are discussed

by Caldwell in Country Life in America for December.

Dr. Sherman’s bulletin on Gutta Percha and Rubber of the Philip-

pine Islands is being reprinted in 7%e Far Eastern Review, of Manila,

beginning with the issue of September.

According to No. 5 of the current volume of the Bulletin du Jardin

Impérial Botanique de St. Pétersbourg, the living collections of plants

at that institution in 1903 numbered 34,887 species and varieties, of

which 27,516 required the shelter of plant houses.

An account of Bauhin’s herbarium, with determinations by A. P.

de Candolle, is published by Casimir de Candolle in Vol. 4, No. 3, of

the Bulletin de P Herbier Boissier. i

M. Correvon, of Geneva, has recently issued an account of the

first Congress of Alpine Gardens, held at the Rochers de Naye in

August.

The Journals. — Botanical Gazette, November : — Jeffrey, “A

Fossil Sequoia from the Sierra Nevada”; Shull, * Place-Constants

for Aster prenanthoides" ; Robinson, “A New Sheep-poison from

Mexico" ; Nelson, * Some Western Species of Agropyron 7: MacMil-

lan, * Note on some British Columbian Dwarf Trees"; Jeffrey and

Chamberlain, “Celloidin Mechanique" ; and Life, “An Abnormal

Ambrosia."

The Bryologist, November : — Fink, “ Further Notes on Clado-

nias — IV”; Grout, * Hepatics with Hand Lens.”

Bulletin of the Torrey Botanical Club, October: — Bessey, “ The

Chimney-shaped Stomata of Holacantha Emoryi” ; Kellicott, “The

Daily Periodicity of Cell-division and of Elongation in the Root of

Allium”; Emerson, “ Relationship of Macrophoma and Diplodia ” ;

Rydberg, “Studies on the Rocky Mountain Flora — AIL

Bulletin of the Torrey Botanical Club, November : — Cushman, |

* Desmids from Newfoundland”; Horne, “An Anomalous Structure

on the Leaf of a Bean Seedling”; House, “The Nomenclature of

Calonyction bona-nox? ; Murrill, “The Polyporacea of North Amer-

ica —IX"; Britton, “On Pisonia obtusata and its Allies."

Journal of the New York Botanical Garden, November : — Britton,

“ Report on Exploration of the Bahamas."

IIO THE AMERICAN NATURALIST. [Vor. XXXIX.

Vol. ı of the Memoirs of the Horticultural Society of New York,

issued late in 1904, is devoted to the important Proceedings of the

International Conference on Plant Breeding and Hybridization held

in New York City in October, 1902.

Part 3 of the third series of Minnesota Botanical Studies contains

the following articles: — Lyon, *'The Embryogeny of Ginkgo";

Leavitt, “Observations on Callymenia pAyllophora? ; Warner, “ Ob-

servations on Zndocadia muricata”; Mueller, “Observations on

Laminaria bullata”; Howe, “Minnesota Helvellinez "; Polley,

* Observations on Physalacria inflata”; and Freeman, “ Symbiosis

in the genus Solium.”

The Ohio Naturalist, November: — Kellerman and Gleason, “ Notes

on the Ohio Ferns”; Schaffner, “Leaf Expansion of Trees and

Shrubs in 1904”; Gleason, “A New Sunflower from Illinois ” ;

Schaffner, “Twigs of the Common Hackberry,” and “Six Mutating

Plants.”

The Plant World, October : — Safford, “Extracts from the Note-

Book of a Naturalist on the Island of Guam — XXIII”; Barrus,

“Pussy Willows”; Barrett, “Tanier, the Oldest Crop ». Atwell,

“Propagation by Petiole Buds”; Schneck, “ Hybridization in the

Honey Locust.”

Rhodora, October : — Fernald, “ The American Representatives of

Pyrola rotundifolia” ; Hoffmann, “ Notes on the Flora of Berkshire

County, Mass.” ; Knowlton, * Notes on the Flora of Day Mountain,

Franklin Co., Me.”; G. E. D., “The Death of William Wendte” ;

Waters, “ Asplenium ebeneum proliferum”; Day, "uncus effusus

compactus in N. H.”; Chamberlain, “ Plantago elongata in Mass.”

Torreya, October :— Underwood, “The Early Writers on Ferns

and their Collections — III”; Murrill, “A New Species of Poly-

porus from Tennessee”; Britton, “The Florida Royal Palm ui

Berry, *Otto Kuntze on Sequoia."

Torreya, November :— Harper, “ Two Hitherto Confused Species

of Ludwigia”; Murrill, “ A Key to the Perennial Polyporacez of

Temperate North America”; Gleason, “ Additional Notes on South-

ern Illinois Plants”; Cockerell, “ Hymenoxys insignis”; Britton,

“ Rhynchospora Pringlei” ; Shafer, “ Notes on Cuban Plants ”; Grant,

“A Peculiar Pea Seedling "; Millspaugh, “ A New Bahaman Euphor-

bia”; E. G. Britton, “The Effect of Illuminating Gas on Trees and

No. 458.] NOTES AND LITERATURE. III

Shrubs”; Greene, “A Name explained [Xolisma or Cholisma]" ;

Howe, Exogenous Origin of Antheridia in Anthoceros."

Vol. 2, No. 3, of Contributions from the Botanical Laboratory of the

University of Pennsylvania contains the following articles : — Phillips,

* A Comparative Study of the Cytology and Movements of the Cyan-

ophycex”; Watson, “Structure and Relation of the Plastid?; Harsh-

berger, “ The Relation of Ice Storms to Trees”; Conrad, “ Phyllody

in Nelumbo”; Cooke and Schively, * Observations on the Structure

and Development of Zpiphegus virginiana” ; Boewig, “ Histology and

Development of Cassytha filiformis" ; Farr, * Notes on some Interest-

ing British Columbian Plants"; Macfarlane, “ The History, Structure

and Distribution of Sarracenia Catesbei” ; and an announcement of

three phanerogamic monographs shortly to be published.

Vol. 2, Part 2,.0f the Annals of the Royal Botanic Gardens, Pere-

deniya contains a second part, well illustrated, of Wright's “The

Genus Diospyros in Ceylon," a paper by Lock “On the Growth of

Giant Bamboos," one by Svedelius “On the Life-History of Znalus

acoroides,” and the first of “ Studies in Plant Breeding in the Tropics,"

by Lock. .

Botanical Gazette, December : — Copeland, “The Variation of

some California Plants”; Newcombe, “Klinostats and Centrifuges

for Physiological Research”; Cooley, “ Ecological Notes on the

Trees of the Botanical Garden at Naples"; Bergen, "Relative

Transpiration of Old and New Leaves of the Myrtus Type"; Coulter

and Chrysler, *Regeneration in Zamia"; and Parish, “New or

Unreported Plants from Southern California."

The Bryologist, January: — Smith, “ William Starling Sullivant,

with Portrait"; Grout, “Spore Distribution in Buxbaumia”; E.G.

Britton, “Notes on Nomenclature.— IV, The Genus Neckera."

The Fern Bulletin, October: — Fitzpatrick, “The Fern Flora of

Montana"; Maxon, “Notes on American Ferns — VII"; Dukes,

“Fall Fruiting of Osmunda”; Foster, “The Broad Wood Fern in

Washington”; Dukes, “ Babyhood of Ferns ”. Woolson, “ Nephrod-

ium pittsfordensis” ; Fitzpatrick, “ Notes on the Ferns of Washing-

ton”; Cocks, “Notes from Louisiana ”. Clute, “The Jamaica

Walking Fern"; Eaton, “Pellea ornithopus ”. Hahne, “ Forking

Ferns” ; Phelps, “New Stations for two rare Connecticut Ferns” ;

Schneck, * Asplenium Ruta-muraria on the Towers of Milan Cathe-

dral” ; and Clute, “ Adiantum Capillus- Veneris in Pennsylvania."

)

112 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

The Plant World, November : — Safford, “ Extracts from the Note-

Book of a Naturalist on the Island of Guam —XXIV ”; W. W.

Bailey, “River Botanizing ” ; Wetzstein, “ The White Prickly Poppy

in Northwestern Ohio."

Rhodora, November: — Brainerd, “Hybridism in the Genus

Viola” ; Blanchard, “ A New Species of Blackberry”; House, “A

New Violet from New England”; Clark, “ Dalibarda repens near

Boston "; Ward, “ Mimulus moschatus in Mass.” ; -and Holt, “ Subu-

laria at East Andover, N. H.”

Torreya, December: — Shafer, “ The American Sennas”; Rich-

ards, “ A Case of Irregular Secondary Thickening”; Sumstine, “ The

Boletacex of Pennsylvania”; Berry, * Recent Contributions to our

Knowledge of Paleozoic Seed-Plants” ; Wilson, “Some Introduced

Plants in Cuba.”

(Wo. 457 was issued February 20, 1905).

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XXXIX,

VOL

t k

the Structure of the Vascular Cyl

THE

AMERICAN

NATURALIST

A MONTHLY JOURNAL

DEVOTED TO THE NATURAL SCIENCES

IN THEIR WIDEST SENSE

CONTENTS

I. The Anatomical Changes in

n of Catalpa .

Origin of Amber

to the Hybridi

P. HENDERSON 147

. A. CUSHMAN AND W.

t's British Freshwater -

ts, Wes

pes ; ==

The American Naturalist.

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THE

AMERICAN NATURALIST.

Vor. XXXIX. March, 1905. No. 459.

THE ANATOMICAL CHANGES IN THE STRUC-

TURE OF THE VASCULAR CYLINDER INCI-

DENT TO THE HYBRIDIZATION

OF CATALPA.

D. P. PENHALLOW.

In 1889 Prof. C. S. Sargent published an account of an inter-

esting and newly observed case of hybridization between two

species of Catalpa which he designated as Catalpa x J. C. Teas

in reference to the origin of the tree in the nursery of Mr. Teas

at Carthage, Missouri! The account referred to states that

Catalpa kempferi was planted in 1864 in a nursery containing

C. speciosa and C. bignonioides. Eventually the first species

produced a single pod of seeds which were wholly unlike any-

thing hitherto known. When these seeds were planted, they

produced a tree almost intermediate in character between C.

kempferi and one of the ‘American species. Mr. Teas was of

the opinion that the cross was with C. speciosa, while Prof.

Sargent considered C. bignonioides as the other parent, basing

his conclusion upon the fact that C. speciosa flowers two to

three weeks earlier than C. Aampferi, while the flowers of C. big-

1 Garden and Forest, vol. 2, 1889, p. 303-

113

114 THE AMERICAN NATURALIST. [Vor. XXXIX.

nontoides are contemporaneous with those of the Japanese spe-

cies. No other evidence has been forthcoming since then, so

far as I am aware, and the real American parentage of a most

noteworthy addition to the ornamental trees of this country still

remains in doubt. Within the last twelve years, opportunities

have been presented to inquire into the evidence which might

be secured from an anatomical point of view, and to determine

ic NA

omen:

$.-

as.

FLA ad

- sehen

tede

"el diui.

the summer w

ood; /, zone of spiral and scalariform tracheids forming a limiting layer of

uniform width and chiefly without radial extensions, but repeated at /’in a second zone

ent 1 1 +} +1 1 1 1 1

> >

to what extent the external alterations attendant upon hybridi-

zation correspond with internal structural changes. It was felt

that the answer to this question might very largely contribute

to a solution of the difficult problems relating to the origin of

species by either mutation or hybridization, and admit of a more

precise limitation of the characters which define a species. The

No. 459.] ANATOMY OF CATALPA HYBRIDS. IIS

importance of this latter point of view was the more strongly

impressed upon me because, in the course of studies relating to

the recognition of species among the North American Coniferales

as determined by the anatomy of the woody axis, I had been

obliged to adopt the working hypothesis that there are no varie-

tal forms in the sense commonly employed and as expressed in

variations of the external organs, and that where these variations

arise, they define species as certainly, though not as conspicu-

ously as in other cases. Fortunately I already had in my posses-

sion, wood of C. bignonioides and C. speciosa, while fresh material

of the latter was also obtained from trees growing in the grounds

of McGill University. About twenty years ago, a specimen of

Teas hybrid was planted out in the College grounds, and it has

proved perfectly hardy up to the present time, though two other

specimens planted about eight years ago were completely killed

during the two winters of 1902 and 1903. ` Recently Mr. Burton

Landreth of Bristol, Pa., who possesses a growth of C. kempferi,

very kindly sent me a specimen of wood, and it has thus become

possible to bring the wood structure of the hybrid into direct

comparison with that of the three species among which its par-

ents are to be found. Later specimens of C. kempferi from

Mr. J. G. Jack of the Arnold Arboretum, have also enabled me

to institute more extended comparisons. Before proceeding to a

discussion of the results obtained, it will be desirable to recall

the essential features of the hybrid as given by Sargent, and

to see the direction in which such evidence tends.

«'The hybrid is an erect, vigorous and rapid growing tree,

with the thin, scaly bark of the American species. The leaves

of this tree are much larger than those of either of its parents,

having, when they first appear, the velvety character and purple

color peculiar to those of the Japanese plant, and the reddish

spot at the insertion of the petiole with the leaf blade which

characterizes that species. They more generaly resemble

those of the Japanese species in shape, color and texture, while

the pubescence which covers the lower surface is almost inter-

mediate in character between that of the American and of the

Japanese species. The inflorescence is much larger than that

of the American or of the Japanese plants, being fully twice as

116 THE AMERICAN NATURALIST: |. [Vor. XXXIX.

large as that of C. bignonioides and more than three times the

size of C. kempferi. The flowers are intermediate in size; in

color and markings they most nearly resemble those of the

American species, although a tinge of yellow in the throat of

the corolla points to their Japanese descent. The fruit of the

hybrid is almost intermediate in size between those of the two

parents, as are the seeds, which are perfectly fertile and often

Fic. 2.— Catalpa kemfferi. Transverse WAREN, x 44. a, vessels of the primary zone iio

thylos Pe 2 dips espe

the thyloses; c, vessels of the last of the season's growth; Z, thin-walled cells of the

spring wood; e, smaller and somewhat thicker-walled cells of the summer wood; J 20

of spiral and scalariform tracheids limiting the growth ring and showing radial extensions

in connection with the last small vessels.

reproduce the original form in every particular. When, how-

ever, seedlings show a tendency to vary from the original form,

the variation is generally in the direction of the Japanese rather

than of the American parent.”

** The hybrid is a more vigorous tree than either of the Amer-

ican or the Japanese species, and it grows rather more rapidly.

No. 459.] ANATOMY OF CATALPA HYBRIDS. 117

Of its value as an ornamental tree there can be no doubt. Its

larger size and more rapid growth, its better habit and more

showy inflorescence, make it a far more valuable ornamental tree

than the Japanese species; it is more hardy than either of the

North American species, and although the flowers are smaller,

the panicles and the number of the individual flowers are much

larger.” The inflorescence of the hybrid is also remarkable for

Fic. 3.— Catalpa speciosa. Transverse section, X 44

all an

e, tangential and concentric bands

spring wood; d, the narrow zone of the summer wood;

iting zone of wood tracheids.

of fiiius pd parenchyma ; /, the narrow, lim

its prolonged duration which extends from June until September

as presented by specimens grown here.

We may now turn to a study of the internal structure of the

hybrid and of the three related species in order to determine (1)

if the crossing has made an impress upon the anatomical struc-

ture, or if it is simply expressed in external characteristics; (2)

118 THE AMERICAN NATURALIST. (VoL. XXXIX.

if there is any anatomical evidence which will determine the

species with which C. kempferi was crossed; and (3) if this

evidence bears any relation to the fixity of the form and in any

way defines a new species. To this end it will be necessary to

elaborate the separate diagnoses and compare them with one

another, as also with differences in color, form, and texture as

applicable to the leaves and flowers.

Teas Hysrip (Figs. I, 5).

Transverse.— Growth rings very broad, the spring wood thin but the dis-

tinction between it and the summer wood not clearly recognizable. The

wood cells of the earliest growth sometimes tangentially elongated, in more

or less. obvious radial rows and rather large with rather thin walls ; the struc-

ture of the later growth chiefly the same throughout the growth ring, the

cells hexagonal, in somewhat definite radial rows, not thick-walled, very

variable in size with little or no diminution toward the outer limits. Woo

parenchyma confined to the composition of the vessels and to the earliest

spring wood where the cells become distinctly larger and more resinous.

Wood tracheids prominent, squarish, in very definite radial rows, forming a

narrow zone of about six elements on the outer face of the growth ring, but

locally extended radially inward opposite the smaller vessels with which they

join so as to form tracts of variable width; also uniting with the smaller

vessels to form a second and more internal, discontinuous zone of very

irregular width and form. Vessels at first medium and forming a single

layer with strongly developed thyloses; becoming abruptly larger in the

second layer, radially oval or oblong and chiefly single, but sometimes 2-3

compounded radially and tangentially and largely devoid of thyloses ; soon

diminishing in size and number, radially compounded and much scattered

in irregular groups of 2-6 throughout the growth ring, finally reduced some-

what abruptly in the last growth of the season to the dimensions of tra-

cheids with which they coalesce into irregular tracts. Medullary rays prom-

inent, numerous, somewhat resinous especially in the spring wood, 1-3 cells

wide, distant upwards of 178 p. 2

Radial. — Medullary rays somewhat resinous, the cells straight, rather uni-

form in height, very variable in length and from 3-4 times longer than high,

or again very short and much higher ; the upper and lower walls rather thick

and finely pitted; the terminal walls straight or curved and finely pitted ;

the lateral walls not pitted except opposite vessels and then with small,

numerous, oval and unequal pits. Tracheids of the limiting zone with spi-

ral and scalariform structure which merges into 1—2 rows of simple pits on

the radial walls. Wood parenchyma somewhat resinous and exceedingly

variable; when adjacent to the spiral tracheids of the summer wood, very

No. 459.] ANATOMY OF CATALPA HYBRIDS. II9

narrowly cylindrical, when adjacent to vessels, usually short cylindrical and

bearing numerous transversely oval or oblong pits on the radial walls. Ves-

sels often much shorter than broad, the radial walls with multiseriate, hex-

agonal pits throughout, the orifice transversely oblong.

Tangential.— Rays very numerous, low to medium, 1-3 cells wide, some-

what resinous; the cells chiefly oblong, rather thin-walled, those of the

extremities much larger and more variable. Vessels with multiseriate, hex-

agonal or more commonly oval, bordered pits which frequently become

simple, distant, and transversely oval or oblong. The tangential walls

of the wood parenchyma with numerous transversely oval or oblong pits.

Tracheids often devoid of spiral and scalariform structure which is replaced

by upwards of 3 rows of simple pits.

The features thus described will be found in the figures of

tion, X 44. a, very large vessels of the p

essels of the secondary zone ee apes without “0a

the greatly reduced and distant vess essels of the summer wood which do not appear

„the broad zone of the thin-walled jos of the spring

trach

Fic. 4.— Cutalpa bignonioides. Transverse sec

mary zone showing few thyloses ; 5, the v

wood; e, diagonally radial tracts E spiral and scalariform = connecting with the

outermost and most reduced vessels; e, tangentially — of tracheids center-

ing in larger vessel g condary zone.

the transverse and longitudinal sections. As one of the parents

of this hybrid is known to be C. kempferi, its diagnosis may be

120 THE AMERICAN NATURALIST. [Vor. XXXIX.

given and brought into direct comparison in order to ascertain

what characters have been derived from it. By elimination it

wil then be possible to refer the remaining characters to either

C. speciosa or C. bignonioides.

C. kempferi (Figs. 2, 6).

Transverse.— Growth rings very broad. Differentiation of the spring

and summer woods well defined (?), the latter constituting the bulk of the

growth ring and defined by a somewhat abrupt transition in the form, size,

and thickness of wall of the component cells. The spring wood composed

of large, variable, squarish-hexagonal and tangentially elongated, non-resin-

ous, and thin-walled cells which form a limiting zone external to the previous

growth ring; soon replaced by the somewhat abruptly smaller, rather thin-

walled, hexagonal and radially elongated cells of the summer wood which

diminish almost imperceptibly toward the outer face of the growth ring-

Wood parenchyma strictly confined to the composition of the vessels.

Tracheids conspicuously squarish, rather uniform, in regular radial rows,

more or less resinous, rather thick-walled and forming a limiting layer

upwards of six cells thick on the outer face of the summer wood, or oppo-

site the most recently formed small vessels, joining with the latter to form

radially extended tracts of irregular form and extent, or even forming

detached groups centering in small vessels, so as to form a second zone

of imperfect development. Vessels somewhat numerous and scattered

throughout the growth ring; those of the early spring wood with strongly

developed thyloses; at first rather small, numerous and round, but abruptly

enlarging with the corresponding transition from the spring to the summer

wood cells, and becoming oval or radially extended and 2-3 compounded

in radial series, predominant; again abruptly reduced in size and number,

sometimes radially 2-3 seriate, and thence continuing without much varia-

tion to the region of the outer summer wood where they are once more

cheids. ary rays prominent, sparingly resinous, 1-3 cells wide,

distant upwards of 427

adial.— Medullary rays sparingly resinous ; the cells within the region

of the early spring tracheids chiefly short; isodiametric; the upper and

lower walls rather thick and strongly pitted; the terminal walls thicker

and more strongly pitted; the lateral walls with numerous small pits in

more or less definite radial series; in older parts of the growth ring the

cells increase greatly in length, except the marginal ones which remain

short and become much higher, the pits on the lateral walls opposite ves-

sels become much larger and oval. Wood parenchyma of the spring wood

composed of short and thin-walled cells which bear rather numerous, -

versely oval, simple pits on the radial walls; those of the vessels of later

No. 459.] ANATOMY OF CATALPA HYBRIDS. 121

growth much longer and narrower. Tracheids of the summer wood nar-

row, spiral, scalariform, and pitted, and showing all transitional forms from

simple spirals to hexagonal bordered pits in ı-3 series. The radial walls

of the vessels with numerous hexagonal pits having rather large, trans-

versely oval or oblong openings.

Tangential.— Medullary rays rather numerous, resinous, low to medium

and 1-3, chiefly 2 cells wide; the cells rather thick-walled, hexagonal.

Tangential walls of the vessels with numerous and variable, transversely

oval, oblong or long linear, often simple pits. The tangential walls of the

spring parenchyma with numerous round or transversely oval, chiefly simple

pits; those of the early spring wood cells with transversely linear, narrow

and rather numerous pits.

A comparison of the transverse and tangential sections for

this species, with those for the hybrid, makes the general rela-

tions of the two very obvious, but a more critical examination of

them is necessary. In each case the wood is characterized by

the great breadth of the growth ring. In C. kempferi, the thin-

walled spring wood constitutes a rather narrow zone representing

but a small volume of the total growth for the season. Precisely

the same is also true of the hybrid with the difference that the

volume is reduced to about one half what is to be found in the

former, showing the definite influence of one parent. In each

case the wood parenchyma is confined to the composition of the

vessels or to the earliest spring wood, and there is no feature in

them which can be directly ascribed to C. &emfferi. A very

definite connection between C. kempferi and the hybrid, appears

in the distribution of the tracheary tissue which, in the latter,

forms a well defined limiting layer occupying the same position

as in the former but characterized by greater uniformity of width.

This is undoubtedly due to C. kempferi in the first instance, but

ultimately it is to be regarded as a resultant effect from the

interaction of the two parents as will appear later. In addition

to the limiting zone of tracheids which sometimes extends radi-

ally inward as in C. kampferi, though not generally to the same

extent or so frequently, it is to be noted that in the hybrid there

is a second and more internal zone of tracheary tissue which cen-

ters in the small vessels of the outer summer wood and which

forms tangentially extended tracts of a very well defined char-

acter. This feature is one of the most prominent structural

122 THE AMERICAN NATURALIST. [Vor. XXXIX.

changes, and it points with great force and directness to the

influence of some other parent than C. kempferi, although this

has also exerted an influence. In the distribution, size, and

character of the vessels, there are but few features which serve

to guide us in forming a conclusion, but it will be noted that the

Fic. 5.— Catclpa teasi. ‘Vangential section, X 61. Showing vessels with few or no thyloses,

and the rather 1 li f lenticular f 2-3 cells wide

conspicuous thyloses of C. kempferi have practically disappeared

in the hybrid though retained in the initial row of vessels which

have increased slightly in size and are confined to a much nar-

rower, radial zone. This points without doubt to the influence

of the other parent. In the outer regions of the growth ring,

the vessels are seen to be conspicuously smaller and on the

No. 459]. ANATOMY OF CATALPA HYBRIDS. 123

whole, more scattering in the hybrid than in C. kempferi, a

feature undoubtedly derived from the other parent. The med-

ullary rays offer no evidence of value in favor of either parent,

since in each case they present the same features of structure.

In the structure of the medullary ray as presented in radial

section, some features are worthy of consideration. The gener-

ally short, isodiametric cells of C. kempferi are more commonly

replaced in the hybrid by longer and very variable cells, the

upper, lower, and terminal walls of which are marked by fine

pits, all of which features must have been derived from another

parent than C. kempferi in which the walls are distinguished by

coarse pits. While in the latter species the pits on the lateral

walls of the cells are rather large and oval, in the hybrid they

become small, numerous, and unequal. In each case the spiral

and scalariform tracheids of the summer wood show transitional

forms leading to the development of pits, but while in C. kæmp-

feri these latter structures are hexagonal, bordered, and in 1-3

series, in the hybrid they are usually simple and in ı-2 rows

only, thus showing a modification which must be attributed to

the other parent.

In a tangential section the medullary rays correspond in

approximate number and height, as also in the number of

series of cells entering into their composition, but while in C.

kempferi the cells are rather thick-walled and hexagonal, in the

hybrid they are rather thin-walled and oblong, the marginal cells

becoming much higher and more variable. From this compari-

son it is obvious that C. kempferi has influenced the hybrid in

very definite ways, while it is equally clear that the latter pre-

sents a number of characteristics which could have been derived

only from C. speciosa or C. bignonioides, and in order to deter-

mine which, we may next compare C. speciosa. An inspection

^ of a transverse section of this wood shows that it possesses

features of structure which are in very marked contrast to what

may be found in either of the preceding species, but in order to

make these differences clear, a diagnosis may be given before

proceeding to a detailed comparison.

124 THE AMERICAN NATURALIST. | [Vor. XXXIX.

C. speciosa (Figs. 3, 7).

Transverse. — Growth rings narrow, rather uniform, consisting of about

one half spring and one half summer wood distinguished by their variations

in (1) size of cells, (2) the thickness of the walls, and (3) the disposition of

the cells. Cells of the spring wood large, thin-walled, hexagonal or some-

times tangentially extended, in somewhat obvious radial rows; those of the

summer wood hexagonal, uniform, thick-walled, smaller and 07 at all in

radial rows. Wood parenchyma dark and resinous, the cells forming tan-

gential and concentric series at frequent intervals, chiefly in the summer

wood. Wood tracheids thin-walled, few, in two or three rows terminating

the growth ring as a layer of uniform thickness. Vessels of the earliest

spring wood at first very large, oval or round, rarely compounded, and

chiefly devoid of thyloses ; quickly reduced and soon compounded in radial

and tangential series and finally reduced to about twice the diameter of the

wood cells; very numerous throughout the growth ring to which they

impart an element of great porosity. Medullary rays somewhat numerous,

dark, 1-several cells wide, distant upwards of 445 y.

Radial. — Wood parenchyma abundant, the cells in parallel rows, 14.6 p

to 100 y wide; sparingly resinous, the radial walls with rather numerous,

small and simple pits. Medullary rays sparingly resinous; the cells chiefly

uniform in height except the marginal ones which are very variable, short

in the summer wood and upwards of 24 times the height, or in the spring

wood several times longer than high, the upper and lower walls sinuately

unequal, rather thick, conspicuously pitted; the. terminal walls straight,

strongly but rather finely pitted; the lateral walls devoid of pits. except

opposite vessels where they commonly show a fine sieve-plate structure

or are otherwise numerously pitted. Vessels chiefly rather short but very

variable, the terminal walls rather thick but not pitted ; the radial walls with

‚multiseriate, very variable, hexagonal, round, oval, transversely oval or

oblong, often much elongated and distant pits, the orifice finally becoming

a much elongated, narrow slit without a border, thus showing transitions

into scalariform structure. Radial walls of the spring wood cells with

rather small, longitudinally oblong pits in vertical series. Tracheids of the

summer wood interspersed with wood parenchyma, the radial walls spiral

and scalariform and merging into rather small, oval, bordered pits upwards

of 5-seriate.

Tangential.— Medullary rays numerous, low to very high, often equal

to 2 mm., dark, resinous, one to unequally multiseriate and upwards of 5 cells

wide; the cells small, round or oval, thick-walled, variable, the terminal

cells commonly oblong. Wood parenchyma of the spring wood composed

of short cylindrical cells with square or fusiform ends, the tangential walls

with numerous, multiseriate but small, transversely oval, bordered pits.

Tangential walls of the vessels with numerous small, multiseriate, hexago-

nal or transversely oval, bordered pits.

No. 459] ANATOMY OF CATALPA HYBRIDS. 125

A careful analysis of this diagnosis shows that the most

marked deviations from the characters embodied in the hybrid,

are to be found in (1) the growth rings which are always several

times less in radial extent and far more porous, (2) in the charac-

ter of the initial layer of vessels which are always very large and

devoid of thyloses, (3) in the character of the vessels of later

Fic. 6.— Catalpa kempfert. Tangential section, X 61. oct. vessels with numerous thy-

loses and the low, rather numer ys of lenticul wards of three cells wide.

growth, which are always much compounded and much smaller,

their reduction from those of the initial layer being abrupt, (4)

in the presence of numerous resinous wood parenchyma cells

which lie in definite, concentric zones of one cell in width, (5)

in the tangential aspect of the medullary rays which are exceed-

ingly variable in height, of very unequal width and upwards of

126 THE AMERICAN NATURALIST: [Vor. XXXIX.

5 cells wide. These features are of so pronounced a nature as

to leave no doubt whatever as to the fact that C. speciosa is not

in any way concerned in the production of the hybrid, since none

of its characteristics are to be met with in the latter. It now

becomes necessary to determine as a final factor, whether the

features of the hybrid which we have already seen cannot be

accounted for as being derived from C. kempferi, are in any

way attributable to C. bignonioides.

C. bignonioides (Figs. 4, 8).

Transverse— Growth rings very broad. The summer wood not sharply

defined but distinguishable by (1) the smaller size of the wood cells, (2) the

reduction of the vessels, and (3) the presence of groups or tracts of tra-

cheids. Spring wood composed of large, variable, hexagonal, and tangen-

tially elongated cells in somewhat obvious radial rows, the walls thin; soon

replaced by the smaller and radially extended cells of the summer wood

which diminish very gradually toward the outer limits of the growth ring.

Wood parenchyma confined to the structure of the vessels. Tracheids

rather thick-walled, non-resinous, squarish or tangentially extended, in

radial rows confined to the outer portions of the growth ring where they

form irregular and tangentially extended tracts of variable, often great

extent in two series; the inner rather broad and strictly tangential, the

rather large tracts more or less confluent and continuous, the outer formed

of narrow, diagonal and chiefly free tracts projected inwardly from the

outer limits of the growth ring. Vessels of the spring wood with strongly

developed thyloses, at first large, oval or round, single and strongly pre-

dominant; soon becoming 2-3 compounded in radial series and steadily

diminishing in size, shortly becoming single and more distant, and finally

replaced wholly by groups of tracheids. Medullary rays prominent, 1—

several cells wide, sparingly resinous, distant upwards of 462

Radial. — Medullary rays sparingly resinous; in the spring wood the cells

are upwards of six times longer than high, the upper and lower walls very

thin and barely pitted, the terminal walls thin and finely pitted, the lateral

walls with occasional fine and simple pits; in the summer wood the cells

are often not much longer than high, the upper and lower walls finally

rather thick and strongly pitted, the terminal walls rather thick and finely

pitted, the lateral walls when opposite vessels with rather small and com-

monly numerous, oval, simple pits in more or less definite radial series.

ood parenchyma of the first spring wood composed of short-cylindrical

and rather broad cells, the radial walls with numerous, transversely oval

or oblong, simple pits. The tracheids of the summer wood narrowly cylin-

drical and showing all transitional forms from spiral and scalariform to

No. 459.] ANATOMY OF CATALPA HYBRIDS. 127

small, transversely oval, and simple pits, or 2-seriate hexagonal bordered

pits. Radial walls of the cells of the summer wood commonly with small,

lenticular pits showing a cross. Radial walls of the vessels with multi-

seriate, hexagonal or even transversely oblong, distant pits, the thyloses

with distant, linear and simple pits.

Tangential.— Rays rather narrow, medium to somewhat high, upwards

of 3-seriate, the cells all thin-walled, hexagonal. Tangential walls of the.

vessels with multiseriate, oval pits, the narrow, linear orifice of which is

transverse and often exceeding the pit. Pits on the tangential walls of the

spring wood parenchyma often simple and transversely oblong.

The growth rings of C. bignonioides are seen to be very broad,

thus conforming to what also appears characteristic of C. kæmp-

jeri, and what arises as a necessary resultant in the hybrid, but

constituting a feature entirely wanting in C. speciosa. Thus it

appears that the growth rings in C. speciosa are approximately

only one fifth of the radial dimensions in either the hybrid or C.

bignonioides. While in general terms this difference may be

said to exist, it cannot be taken as a differential character of

leading importance for the reason that under certain circum-

stances of growth, the hybrid may develop equally narrow

rings. Putting this factor to one-side, we then find that the

structure of the growth ring affords a very definite means of

determining any possible relationship. The region which I con-

sider as probably representing the spring wood, is several times

broader than in C. kempferi, and the contraction of this zone in

the hybrid must be viewed as due to the direct influence of the

latter species, The vessels of the early spring wood are large

and they increase in size for some distance within the limits of

the spring wood, so as to form a rather broad zone without any

well defined distinction of a primary and secondary zone as

appears in C. kempferi and more prominently in the hybrid, and

it is probably correct to say that the limitation in size and dis-

tribution which is expressed in the latter, is the direct result of

the dominating influence of the large vessels of C. bignonioides.

The influence of the latter is also expressed in the general dis-

tribution of the vessels. In C. kempferi, C. bignonioides, and

the hybrid, the vessels gradually diminish in size toward the

outer limits of the growth ring, but à comparison of their dis-

tribution in the first and last shows that the hybrid occupies an

128 THE AMERICAN NATURALIST. [Vor. XXXIX.

intermediate position between the first two in such a manner as

to show the direct influence of the latter in a reduction of both

size and number in the outer summer wood. This feature is

again correlated with the distribution of the tracheids. Our

diagnoses have shown that in C. kempferi these elements form

Fic. 7,— Catalpa speciosa. ‘Tangential section, X 61. wing the vessels with rather few

Showi:

thyloses and the exceedingly high rays of variable width, composed of several rows of

thick-walled cells.

a limiting zone which is locally increased in thickness in a radial

direction opposite the small vessels of the outer summer wood,

with which they coalesce to form irregular tracts; or again cen-

tering in small vessels so as to form a second zone of small and

rather distant tracts. The same feature appears also in C. big-

nonioides but in such a modified form as to constitute a distinc-

No. 459.] ANATOMY OF CATALPA HYBRIDS. I29

tive character. Thus the tracheids lie in two zones. In the

outer zone the tracheids form disconnected tracts of variable

form and extent, which are rarely connected by a narrow zone of

tracheary tissue on the outer face of the growth ring. These

tracts are neither radial nor tangential in disposition, but the

resultant of these two directions, and as they project diagonally

Showing vessels with numerous

A £ 9h 11 14

4. T

Fic. 8.— Catalpa bignonioides. Tangential section, X 61.

y MENT! 3 «Hh 1; 4 | BER \ blong

inward, they join with very small vessels which constitute the

final phase of such structures in the summer wood. In the

second zone of tracheary tissue, the tracheids form tangentially

extended tracts of variable form and size’which are always con-

nected with vessels of larger dimensions than those lying in the

outer zone, and these tracts form an almost continuous series.

130 THE AMERICAN NATURALIST. | [Vor. XXXIX.

In the hybrid two such zones are also found. The inner zone is

composed of tangentially extended tracts of variable form and

size centering in vessels corresponding to those of the inner

zone of C. bignonioides and presenting features which are inter-

mediate between those of the latter species and C. kempfert.

The direct influence of C. bignonioides is thus made very appar-

ent. The outer zone of tracheids consists of a limiting layer of

rather uniform thickness and generally devoid of vessels. Here

and there a tendency to radial extension may be noted, but there

is nowhere anything approaching what is to be met with in either

C. kempferi or C. bignonioides, and the actual structural condi-

tion must be regarded as a resultant from the interaction of

these two species, in which a somewhat equal influence appears

to have been exerted.

In the radial aspect of structure, the influence of C. bignoni-

oides is definitely expressed in the hybrid in (1) the more vari-

able dimensions of the ray cells; (2) in the less coarsely pitted

walls ; (3) the 2-seriate character of the pits on the radial walls

of the tracheids. In the tangential aspect, the influence of the

same species is manifested in the thin walls of the ray cells,

while the influence of C. kempferi is expressed in the character

of the marginal cells. Other features of a minor character also

contribute to the general results thus indicated, a summary of

all of which may most conveniently be presented in a tabular

view, from which I have excluded all characters common to the

hybrid and to the three species.

Comparison of structural variations in Catalpa.

‘Teas C. k - E

Hybrid. | | pey E Sot n " oed No.

Transverse. |

Growth rings very broad . . . . . x | X x E 3

Growth rings narrow, uniform 2 — — — d I

Spring "e: summer wood obvious . — pri eae st 2

Spring and summer wood not distin-

irc bee or iocadiy í defined x — x — 2

Cells of summer wood u he dna thick-

walled, zot at all in radial ro — — — X I

Cells of summe s ino: viciis. shin.

walled in radial row x x Am. 3

No. 459.] ANATOMY OF CATALPA HYBRIDS. I3I

Teas C. kæmp- | C. bigno- | C. speci-

| Hybrid. Seri. nioides osa. No.

Transverse.

Wood parenchyma confined to the ves-

sels and the earliest spring wood . x X Re — 3

Wood parenchyma in TM and

concentric zones of a ur da

throughou — — — x I

Wood tracheids in radial rows

the outer face of the summer Md

radially extended opposite and con-

fluent with the sm ie ve z x X — — 2

Wood tracheids for ing tw x x C Ln 3

Wood spades forming ea tan-

gentia Pu x x — 3

Ta rachis ina terminal layer of

2-3 eol oT o T

Vessels of early | spring wood with

x x x um 3

Vessels of early spring wood with-

ut thylos “ns x I

pe ad throughout often

radially compounde Dy x x x eg 3

Vessels za numerous, chief ys small,

radially and tangentially co n — — = x I

— — ra cells wide, low t

x x x — 3

Medullary’ a T in cells wide, variable — — "e: x I

Radial.

Upper and lower walls of Du cells

finely pitted x iun x x 3

Uppe er u. a walls of the ray cells :

ted . — ER ER Mp I

Tracheids Lei hexagonal pits in 1-3 3 :

Tracheids with 1-2 seriate bordered s. :

Tracheids with hexagonal, very vari-

able, multiseriate pits > Me x :

Tracheids with simple pits n 1-2 rows x -= ^ viri I

Vessels with ullent, q iadi :

its . X x x = 3

Vessels with variable, often "much

elongated, slit-like pits merging

into scalariform structure . . . = a 4

Tangential.

Rays 1-3 cells wide, Mn to medium x x x — 3

Rays upwards A de. s wide, une-

qually multis m = ses x :

Ray cells aeri thick walled, variable — mé er x

Ray cells oblong, thin-walle x ge ver: au :

Ray cells hexagonal, thin -walled . c" pr X T :

Ray cells beu thick-walled . -= x er vue

Total characters . 15 15 14 13 1797

132 : THE AMERICAN NATURALIST. [Vor. XXXIX.

Percentages of characters.

(Those common to all are omitted.)

Number. Percent.

Hybrid 4- en + gy ds sr.

Hybrid + sp o 00.00

Hybrid 4- bignonioides- . I 3.12

Hybrid + kem I 3-12

Kempferi + bignonioides - o 00.00

Kampferi only : ; : : Qu x à : 3 9.4

Bignonioides only . 2 6.24

Hybrid only 2 6.24

Speciosa only 1I 34-4

Speciosa + bignonioides 1 T 13

Speciosa + kampferi I J:

Total 3 99.84

From this percentage summary it appears that C. speciosa

embodies 34.4 % of characters which are peculiar to itself, while

C. kempferi and C. bignonioides possess 31.2 % of characters

which are not only common to each other but also common to

the hybrid, the remaining characters belonging, with one excep-

tion, either to these last two species or to the hybrid. From

these facts therefore, we are abundantly justifed in the fol-

lowing conclusions : —

1. Hybrid characters are expressed in the structure of the

vascular cylinder as well as in external alterations of form and

color. |

2. Catalpa speciosa is not in any way concerned in the pro-

duction of Teas Hybrid. .

3. Teas Hybrid Catalpa is the product of a cross between

C. kempferi and C. bignonioides, thus confirming the conclu-

sions already reached by Sargent on the basis of external mor-

phology.

4. The dominant characters of the hybrid, as expressed in

the internal structure, are those of the Japanese parent as simi-

larly manifested in the external characters.

5. The resultant characters are most strongly exhibited in

transverse section, less so in the tangential, and least of all in

the radial.

No. 459.] ı ANATOMY OF CATALPA HYBRIDS. 133

The question still remains unanswered, as to how far this

hybrid approaches and satisfies the conditions which define a

species. A complete solution of this question would be obtained

in the most satisfactory manner by an anatomical study of

reverted forms of the hybrid, were it possible to satisfy all the

requisite conditions of authenticity, and determine to what

extent the anatomical changes already found to characterize the

hybrid, revert to the structure of the separate parents. Unfor-

tunately such studies have not been possible under the conditions

of the present investigation, and we are therefore compelled to

fall back upon such partial evidence as is afforded by the exter-

nal morphology. Reference to the original description of the

hybrid shows that seedlings exhibit a decided tendency to

reversion with respect to the character of the flower, and that

such tendency is always in the direction of C. kempferi. This

fact makes it clear that the Japanese parent exerts a dominant

influence, while it also shows that the characters are not always

fully fixed. Reference to the original description, however,

makes it clear that such reversion is not displayed by aX seed-

lings but only by some, results which are within the limits of

justifiable anticipation and in strict accord with Mendel’s law.

Possibly our knowledge of all the changes incident to reversion

is not as yet sufficiently complete to admit of a final expression

of opinion as to the actual stability of the hybrid and its status

as a species, but it may be kept in mind that while some seeds

exhibit reversion, others come true to the hybrid form which is

capable of perpetuating itself in succeeding generations. There

is in this case no reason for supposing that this is any less a true

species than large numbers of plants in which hybridization is

an important factor as the starting point for a new line of devel-

opment. With the abandonment of the old idea of fixity of

species, and more particularly in the light of Mendel’s law, we

are led to see that in any case of hybridization there must be

large numbers of progeny which, through reversion, ultimately

disappear, while comparatively few acquire such stability as to

survive in the form of what must be regarded as definite species.

It is only on such grounds that we are justified in regarding as

species the numerous and but slightly differentiated forms of the

134 THE AMERICAN NATURALIST. [Vor. XXXIX.

willows, asters, and the Juglandaceze which Prof. Sargent directs

attention to as undoubtedly illustrating the effects of hybridiza-

tion. Such potential species have always been a source of great

difficulty to the systematic botanist who has been unable to

properly define their limitations in such a way as to make them

recognizable at all times and under all circumstances. The

recent separation of six new species of violets from V. cucullata

by Greene,' and the large number of species of Crataegus now

recognized by Prof. Sargent can only be explained either as

mutant forms or as new species according to the Mendelian law.

Their acceptance as valid species shows that our former notions

of the relations of hybrids and species have undergone radical

change, and that we can no longer accept the limitations which

were formerly supposed to be valid. If we are to accept as

species those forms only in which there is no reversion to the

parental type, and in which there is an absolute fixity of charac-

ters, then the hybrid in question cannot be regarded as a species;

but if, on the other hand, we accept as species, as is now the

custom, those forms which possess strongly defined potentialities,

and in which the tendency to reversion is relatively weak, then

the hybrid in question must be held to be a valid and distinct

species as much as any other plants so defined, and in this sense

it should be known as C. teast, n. Sp.

It only remains on the present occasion, to define the diag-

nosis for the genus Catalpa, and present a differential key for

the recognition of the species, as follows : —

CATALPA.

parenchyma more or less resinous, often strongly so, generally associated

squarish and forming a limiting layer on the outer face of the growth ring

from which irregular tracts may project radially inward, or again form a

secondary zone. Vessels numerous, radially or sometimes tangentially

compounded, with or without thyloses.

Radial— Medullary rays somewhat resinous ; the cells often higher than

1 Ottawa Nat., vol. 12, pir:

No. 459.] ANATOMY OF CATALPA HYBRIDS. 135

long, their upper, lower, and terminal walls rather thick and obviously pitted,

their side walls pitted opposite vessels. Tracheids of the limiting zone

spiral and scalariform and exhibiting transitions to bordered pits. ood

parenchyma cells variable but narrowly cylindrical, the radial walls with

numerous transversely oval, simple pits. The radial walls of the vessels

with numerous, multiseriate, hexagonal pits.

Tangential.— Rays usually numerous and multiseriate, the cells small

and thick-walled.

Synopsis of Species.

Resinous wood parenchyma in concentric zones one cell thick.

Vessels of the primary zone large, oval, devoid of thyloses; those of

the secondary zone small, very numerous, much compounded.

Rays (tang’l) numerous, low to very high, unequally multiseriate,

upwards of 5 cells wide. :

Ray cells (tang’l) small, round or oval, thick-walled, variable.

I. C. speciosa.

Wood parenchyma sparingly resinous, the cells scattering and chiefly con-

fined to the composition of the vessels.

Vessels chiefly large, not much compounded, scattering and gradually

diminishing toward the outer face of the growth ring.

Rays (tang’l) numerous, medium, 1-3 cells wide.

Wood tracheids in two zones ; the outer composed of chiefly

free, radially diagonal tracts; the inner of rather broad,

variable and tangentially extended contiguous tracts form-

ing an almost continuous zone.

‚ Vessels of the primary zone large, oval or round, with

few thyloses. à

Ray cells (tang’l) thin-walled, hexagonal.

2. C. bignonioides.

Rays (tang’l) numerous, low to medium, 1-3 cells wide.

Wood tracheids in one zone, forming a continuous limiting

layer with radial extensions opposite small vessels with

which they unite, sometimes giving rise to detached groups

which thus form a second, discontinuous zone.

Vessels of the primary zone small to medium, round,

with strongly developed thyloses, abruptly enlarging

in the secondary zone and finally becoming 2-3 com-

pounded radially.

Ray cells (tang’l) rather thick-walled, hexagonal.

3. C. kampferi.

Wood tracheids in two well defined zones ; those of the outer

forming a continuous and rather uniform limiting layer

upwards of 8 elements thick ; those of the inner zone form-

136 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

ing a discontinuous tract of variable form and width.

Vessels of the primary zone in a single layer, small with

sparingly developed thyloses, becoming abruptly larger

and devoid of thyloses in the second zone, and finally

sparingly compounded.

Ray cells (tang’l) chiefly oblong, rather thin-walled.

4. C. teasi, n. sp.

THE OCCURRENCE AND ORIGIN OF AMBER IN

THE EASTERN UNITED STATES!

ARTHUR HOLLICK.

A Recent Discovery OF AMBER IN THE CRETACEOUS

DEPOSITS AT KREISCHERVILLE, N. Y.

Preliminary Note.— A recent discovery of amber in consid-

erable quantity, in connection with the Cretaceous deposits at

Kreischerville, Staten Island, N. Y., may be found briefly

recorded by the writer in the Proceedings of the Natural Sci-

ence Association of Staten Island for November 12th, 1904, but

without any extended description or discussion. The discovery,

however, was found to have aroused an unexpected interest in

the subject, and the preparation of this paper was suggested.

Geologic Age and General Description of the Deposits —The

deposits in question consist of clays and sands which represent

a part of the eastward extension of the Amboy clay series of

New Jersey and are included in the Raritan formation, which is

generally recognized as middle Cretaceous in age and approxi-

mately the equivalent of the Cenomanian of Europe, the lower

Atane beds of Greenland, and the Dakota group of the West.

At Kreischerville they have been extensively excavated for

economic purposes and in what is known as the Androvette pit

a section was recently exposed, consisting of irregularly bedded

clays and sands, referable to the geologic horizon above men-

tioned, overlain unconformably by more recent sands and

gravels, the entire series showing more or less disturbance by

glacial action. A view of a portion of the pit is shown in Plate r.

Conditions Under Which the Amber Occurs.— The amber

occurs in a stratum or bed, characterized by layers and closely

packed masses of vegetable débris, consisting of leaves, twigs,

1 Read before the Botanical Society of America, Philadelphia meeting, Dec.

30, 1904. Investigations prosecuted with the aid of a grant from the Society.

137

[Vor. XXXIX.

NATURALIST.

RICAN

THE A

138

‘Aoge S[AARIZ pue sputs ouo20jsto[q 10 Areya , pue Mo[oq spurs

pue sáep snooo?ja:) uooAjeq Ájtuuoguooun Sumoys “A 'N 'pue|s[ uaes ‘ayprasoyosios

I q Ayuuoj IMOUS "A 'N puesi S [Me 3

‘yd e3j9Ao1puy ur uong —'I HLVTI

No.459.]] AMBER IN EASTERN UNITED STATES. I39

and fragments of lignite and charred wood. Pyrite, in nodules,

is also a prominent constituent. This bed, where exposed in

vertical section, appears as if lens-shaped, having an indicated

maximum thickness of about 3 feet and a lateral extent of 18

feet or more. The face of the pit at this place is about 20 feet

high and the lower part of the bed is about ı foot from the

present floor of the pit. The section in which the: bed is

exposed is shown in Plate 2. It is immediately adjacent to the

left of the section shown in Plate 1.

Most of the amber was found in a relatively thick accumula-

tion of finely comminuted lignite and charred wood, of limited

extent, through which it was irregularly distributed. This

matrix yielded nearly all of the larger specimens and a majority of

the smaller ones. The remainder were obtained from the rela-

tively thinner layers of leaves and twigs. A piece of the lignitic

matrix, with fragments of amber enclosed, is shown on Plate 3,

Fig. 34.

Characters of the Amber.— A large part of the amber is in

the form of drops or “tears,” examples of which may be seen

on Plate 3, Figs. 1—23, but irregularly shaped fragments, varying

in size from a large pin's head to a hickory nut, are the most

abundant. They are generally more or less transparent and

yellow or reddish in color, but many are opaque and grayish

white. Some of the best examples of the former are shown on

Plate 3, Figs. 24-32, and a large piece of the latter on Plate 3,

Fig. 33. The finest specimen in size, color, and transparency,

represented by Fig. 32, is about 6 cu. cm. in volume. All of

the figures on Plate 3 are of natural size.

Disposition of the Specimens.— Most of the specimens col-

lected are deposited in the museum of the New York Botanical

Garden and the remainder in that of the Natural Science Asso-

ciation of Staten Island. The only other specimens from this

vicinity which I have been able to locate are included in the

collections at Columbia University. These are three in number

and are labeled respectively, “ Marl pits, Squankum, N. J.”

“Kirby’s marl pit, Harrisonville, N. J.," and “ Valentine's clay

pit, Woodbridge, N. J.” The last mentioned is of good quality

and is about the size of a filbert nut.

*1n320 1oquie pue soAvo[ yoya ur ‘yrd ay} Aq payesıpur ‘paq pue syısodap snoa

dy} JO uorje»gnens Zurwous ‘1 ajd JO 3je[ 9uradjxo We “A "N 'pue[sp uoje3s Ayssy “id 93)93A04puy ur uong —'z ALVIA

[Vor. XXXIX.

No. 459] AMBER IN EASTERN UNITED STATES. I41

PREVIOUS RECORDS OF THE OCCURRENCE OF AMBER IN THE

` EASTERN UNITED STATES.

It is probable that amber is far more common in the Creta-

ceous deposits of the eastern United States than is generally

supposed. The amount that may be obtained at the Kreischer-

ville locality alone is considerable, as evidenced by the relatively

large quantity that was obtained in the few hours devoted to the

work, from the small portion of the exposure examined ; and

reports of its occurrence elsewhere indicate that careful search,

with amber as the object in view, would produce excellent results.

Probably the earliest published record on the subject is con-

tained in an article by G. Troost, entitled : ** Description of a

Variety of Amber and of a Fossil Substance supposed to be the

Nest of an Insect, discovered at Cape Sable, Magothy River,

Anne Arundel County, Maryland” (Am. Journ. Sci., vol. 3, 1821,

pp. 8-15), in which he describes the amber as occurring with

lignite, and says (p. 9): * This lignite seems to be formed of

three varieties of wood, or rather the wood has undergone three

different changes, some pieces of which are entirely charred,

often changed into bituminous wood, and others again having

undergone very little change from the brown lignite. Allthese

varieties, particularly the brown lignite and the charred wood,

are penetrated by pyrites, and are sometimes entirely changed

into it."

' The above account is of considerable interest to us for the

reason that the geologic horizon in which the amber was found

at Cape Sable is approximately the equivalent of that at Kreisch-

erville, and the conditions under which it occurs at both places

are evidently identical. The meaning or significance of the

Charred wood presents an interesting problem, as it apparently

indicates the direct effect of fire, at or immediately prior to the

time when the deposits were laid down, and not that of any

chemical change such as resulted in the gradual transformation

of the wood into lignite. Further than this, its occurrence in

such widely separated localities indicates that whatever the

source of the heat may have been, the effects were far-reaching

and extended over a considerable area. The same author, in the

PLATE 3.

Figs. 1-23. gr drops or ‘‘ tears,” Kreischerville, Staten Island, N. Y.

Figs. 24-33. mber masses and fragments, Kreischerville, Staten nei N.Y.

Fig. 34. Pn containing amber, Kreischerville, Staten Island, N. Y.

Figures are all natural size.)

No. 459-] AMBER IN EASTERN UNITED STATES. 143

article above quoted, also indulges in speculations concerning the

kind of wood from which the amber was probably derived, and

says (p. 13): “But I have not been able to ascertain the species

to which it belongs."

Apparently nothing further was recorded in regard to the

subject until 1830, when S. G. Morton published a paper

entitled: “Synopsis of the Organic Remains of the Ferru-

ginous Sand Formation of the United States, with Geological

Remarks” (Am. Journ. Sci., vol. 17, 1830, pp. 274-295) in which

he mentions (p. 293) “vast deposits of lignite with amber," in

the sections exposed in cuttings made for the Delaware and

Chesapeake canal. Incidental reference to the above may also

be found in a subsequent article * On the Analogy which exists

between the Marl of New Jersey and the Chalk Formation of

Europe” (/bid., vol. 22, 1832, pp. 90-95).

After this, for a period of some fifty years, our native amber

apparently attracted but little attention, or at least there does

not seem to have been anything additional recorded in regard

to it during that time. A popular article, by Mrs. Erminnie A.

Smith, entitled * Concerning Amber," was published in the

American Naturalist, for March, 1880, in which the only refer-

ence in this connection is the following brief paragraph (p. 187) :

* Very little amber has as yet been found in the United States.

Gay Head, Martha's Vineyard, Camden, N. J., and Cape Sable,

Md., only are mentioned as its localities. A barrel full of small

pieces was taken out of the greensand in New Jersey, which

through some mistake was burned."

At a meeting of the New York Academy of Sciences, on

February sth, 1883, Mr. Geo. F. Kunz exhibited a mass of

amber 3 Ib. in weight, which was said to have come from the

Tertiary deposits of Nantucket, and read a paper “ On a large

Mass of Cretaceous Amber from Gloucester County, New Jer-

sey," in which was described a mass weighing 64 oz., found in

Kirby's marl pit, near Harrisonville (Trans. JV. Y. Acad. Sci., vol.

2, 1883, pp. 85-86). In the subsequent discussion of this paper

Dr. J. S. Newberry is quoted as remarking that “in one pit [in

Gloucester Co.] a whole barrel full had been found and burned

by the workmen " ; which remark probably has reference to the

144 THE AMERICAN NATURALIST. [Vor. XXXIX.

incident mentioned in Mrs. Smith's article. In the record of

this discussion may also be found a statement, credited to Mr.

W. E. Hidden, to the effect that amber had been discovered

during the previous summer in the marl beds of North Carolina,

and a hearsay reference to a very large specimen from New

Jersey, which was * found on the shore of Raritan Bay, and now

deposited in the museum at Berlin, Germany."

In 1885 were made the first discoveries of fossil plant remains

in the Kreischerville clays (Proc. Nat. Sci. Assn. Staten Isld.,

Dec. 12th, 1885). These were subsequently described by the

writer (/bid., Feb. 13th, 1886) and at the end of the descrip-

tions may be found the following brief paragraph: “ There are

also little masses of a yellow substance which I take to be a

fossil gum or amber." Mr. Wm. T. Davis also found it there

subsequently, according to the following record: “Mr. Davis

presented unusually fine specimens of lignite, apparently coni-

ferous, from the clay beds of Kreischerville. The specimens

were of the appearance and consistency of jet and contained

considerable amber," (/&;7. March 12th, 1892). The above

mentioned material from Kreischerville was all found in the

immediate vicinity of the deposits recently exposed and probably

from parts of the same bed.

PROBABLE ORIGIN OF THE AMBER.

In 1894 the Cape Sable locality was visited by Mr. A. Bib-

bins, who succeeded in finding and collecting a number of

specimens of amber, some of which were included in the inter-

stices of a log of lignite and were evidently derived from it.

This lignite was examined by Dr. F. H. Knowlton, by whom it

was identified as a new species of Cupressinoxylon (C. bzbbinst),

or in other words the fossil wood of a Sequoia (* American

Amber-producing Tree," F. H. Knowlton, Science, vol. 3, 1896,

pp. 582-584, figs. 1-4). This identification is important for

the reason that it gives us definite information, for the first time,

in regard to the origin of at least a portion of the amber in this

part of the United States, and suggests a probable source for

some of that at Kreischerville, where it occurs in close connec-

No. 459] AMBER IN EASTERN UNITED STATES. 145

tion with the leafy twigs of Seguota heterophylla Vel., and S.

reichenbachi (Gein.) Heer. It may also be of interest to note

that leaves of Sequoia are said to be associated with the amber

of Japan.

Other coniferous remains which have been found in the

Kreischerville clays, and which may have contributed to our

supply of amber, are Widdringtonites reichii (Ett.) Heer., Junt-

perus hypnoides Heer, Dammara microlepis Heer., and Pinus sp.

The genus Dammara is prominently represented in our living

flora by D. australis Lamb, the well known “Kauri” gum tree

of Australia. Its former existence, however, as an element in

the Cretaceous flora of North America, is somewhat problematic,

and is based entirely upon the presence of certain small cone

scales, the exact botanical affinities of which have never been

satisfactorily determined. The occurrence of remains of the

genus Pinus is more significant perhaps than any of the other

three last mentioned, by reason of the fact that the typical

amber of the Baltic provinces in Europe is recognized as a prod-

uct of the extinct Tertiary species, P. suecimifera (Goepp.)

Conw.

ACKNOWLEDGMENTS.

For answers to letters of inquiry on my part I am indebted

to Dr. Lester F. Ward and Dr. F. H. Knowlton of the United

States National Museum, Mr. A. Bibbins of the Woman’s Col-

lege of Baltimore, Mr. L. P. Gratacap and Mr. Barnum Brown

of the American Museum of Natural History, and to Mr. Geo.

F. Kunz, of the United States Geological Survey.

FRESH-WATER RHIZOPODS FROM THE WHITE

MOUNTAIN REGION OF NEW HAMPSHIRE.

JOSEPH A. CUSHMAN AND WILLIAM P. HENDERSON.

Sınce the publication of the Monograph of the Fresh-water

Rhizopods of North America, by Dr. Joseph Leidy, little work

has been done upon this very interesting group, especially as.

regards New England. Their abundance and the singular

beauty of some of the species should make them better known

even to the most casual observer of the microscopic fauna of

our ponds and streams. The number of species obtained from

. New Hampshire was not great yet when compared with the

whole number of shelled forms reported from North America it

is a very fair representation. Certain forms found are appar-

ently new and are reserved for further study.

The region from which most of the specimens were obtained

was not of great altitude nor of high latitude but nevertheless

both of these conditions seem to play an important part in the

comparative size of the individuals of the same species. In the

summary at the end of the present paper is discussed the

bearing of these points as made out from a study of the material

under observation.

The material used in the preparation of the present paper was

of two kinds: mounted and unmounted. The former is in the

collection of the Boston Society of Natural History and repre-

sents the following localities: Saco Lake, Profile Lake, Lone-

some Lake, Lake of the Clouds, Pinkham Notch, Franconia,

Claremont, Gilmore Pond near Profile House, and Scribner's

Brook, Wakefield. The unmounted material was preserved in

formalin and represents the following localities: Pudding Pondat

North Conway ; Intervale; a pond at 5000 feet on Mt. Munroe ;

Mirror Lake in Chatham (all collected by Dr. Glover M. Allen) ;

North Woodstock (including two lots from the Flume, collected

by George A. Fisher); Squam Lake (collected by Herman

148 THE AMERICAN NATURALIST. (VoL. XXXIX.

Gammons); and Mt. Moosilauke (collected by Warren A.

Priest). Identified specimens from this latter group of locali-

ties are preserved in the collections of the writers and are

referred to by slide numbers under each species. For the other

localities the number of the slide in the collection of the Boston

Society of Natural History which contains an identified speci-

men is given. Thus all the localities and species may be

verified by actual material. A mounted set of material from

the second set of localities has been deposited in the collection

of the New England Microscopical Society.

The arrangement of the genera and species follows that of

Leidy's monograph. The determinations also follow the same

work as it is still the standard work of its kind for our species.

The following species and varieties were identified : —

Difflugia globulosa Dujardin.

The test of this species showed considerable variation. It was

usually of coarse sand grains, but in some specimens included

diatom valves, and in a few cases there was a chitinoid mem-

brane with more or less extraneous matter attached to it. Sev-

eral cases of dividing specimens were noted.

Size.— Length, 46-76 y; breadth, 40-87 u; diameter of

aperture, 26-45. As noted by Leidy,

the test composed of coarse sand grains

with a chitinous test.

Localities.— Mt. Munroe (Cushman Coll, nos. 193, 194);

North Woodstock (Henderson Coll., no. 57, Cushman Coll., no.

181) ; Lake of the Clouds (B. S. N. H, no. 4319); Profile

Lake (B. S. N. H., no. 4313); Franconia (B. S. N. H., no.

4307); Saco Lake (B. S. N, H., no. 4324).

the specimens having

are larger than those

Difflugia pyriformis Perty.

of large size. In a col-

No. 459.] WHITE MOUNTAIN RHIZOPODS. 149

mens, the tests presenting a dark brown appearance. Whether

this color was a result of the dark hue of the sand, or arose -

from a lining membrane of brown chitin in which the grains

were incorporated, was not surely made out. One test was

unique: trailing from many points in its surface were long

blackish streamers, one even longer than the test. Several

cases of division were seen.

Sise.— Length, 68-309 u; breadth, 35-201 4; aperture, 15-

87 j: ;

Localities — North Woodstock (Cushman Coll., nos. 183, 187,

Henderson Coll., nos. 51, 53, 63); small pond, 5000 ft. alt.,

Mt. Munroe (Cushman Coll., no. 196) ; Franconia (B. S N: H4

no. 4307); Pinkham Notch (B. S. N. H.; no. 5164) ; Squam

Lake (Cushman Coll., no. 198) ; Intervale (Cushman Coll., nos.

66; 67).

Of D. pyriformis the following varieties described by Leidy,

(p. 99) were found: var. compressa, North Woodstock; var.

nodosa, Intervale ; var. vas, Intervale.

Difflugia urceolata Carter.

Test of the typical form with the urceolate lip. As a rule,

however, the lip was not as well marked as in the specimens

figured by Leidy. —

Sise.— Length, 68 »; breadth, 58 a; aperture, 30 p.

specimen is much smaller than that reported by Leidy.

Locality. — North Woodstock (Cushman Coll., no. 176).

This

Difflugia acuminata Ehrenberg.

Testasa rule of coarse sand grains with the fundus of the

test drawn out into more or less of an acuminate projection.

This species seems to differ more or less in its comparative

breadth as all gradations were noted from very slender to fairly

broad specimens.

Size.— Length, 87-125 &; breadth, 46-60 u;

3l a

Dd. North Woodstock (Cushman Coll, nos.

189) ; Intervale (Cushman Coll., no. 163).

aperture, 22—

182,

150 THE AMERICAN NATURALIST. [VOL. XXXIX.

Difflugia constricta (Ehrenberg).

Test usually of coarse sand grains; a yellow or brown

chitinous membrane with irregularly scattered sand particles

noted in one or two cases.

Sise.— Length, 80-102 p; breadth, 59-75 „a; aperture

22-37 p.

Localities. — Lake of the Clouds (B. S. N. H., no. 4319) ;

Claremont (B. S. N. H., no. 4662); Squam Lake (Cushman

Coll. no. 199); North Woodstock (Henderson Coll., no. 62).

Difflugia spiralis Ehrenberg.

Test of varying construction, in one or two cases built up of

the vermiform chitinous pellets shown in Leidy’s Plate 19, fig-

ure 7; in others, of fine, straight, spicule-like fragments. In

one, many diatom valves were used. The neck showed much

variation in length.

Size. — Length, 44-126 u; breadth, 38-96 mw; aperture,

12-46 u.

Localities. — North Woodstock (Cushman Coll, nos. 182,

183, 190); Squam Lake (Cushman Coll, no. 197); Gilmore

Pond near Profile House (B. S. N. H., no. 4314).

Hyalosphenia cuneata Stein.

Test of delicate chitinoid membrane, colorless and unorna-

mented.

Size. — Length, 60 u; breadth, 42 u; aperture, 24 u.

Locality. — North Woodstock (Henderson Coll., no. 5 3).

Hyalosphenia papilio Leidy.

a a delicate and beautiful case of light straw-colored

chitin.

Size. — Length, 111-118 p; breadth, 67-69 m; aperture,

31-32 p.

Localities. — Mt. Munroe (Henderson C i

à oll., no. 102) ; Mirror

Lake, Chatham (Cushman Coll., no. 1 57).

No. 459.] WHITE MOUNTAIN RHIZOPODS. ISI

Hyalosphenia elegans Leidy.

Test of yellowish brown chitin with the characteristic regular

longitudinal corrugations. In the specimen examined a peculiar

large irregular projection showed near the apex.

Size. — Length, 90 u; breadth, 58 #; aperture, 15 a.

Locality. — Mt. Munroe (Henderson Coll., no. 101).

Quadrula symmetrica (Wallich).

Test as name suggests, composed of a tiling of delicate, un-

marked, square, chitinoid plates. These plates increase in size

toward the fundus.

Size.— Of specimens viewed on broader side, length, 58-78 u;

breadth, 28-46 a; oval end, 14-21 a. One rather larger, but

turned so that a slightly oblique view of the narrower side was

afforded, gave measurements : length, 87 4; breadth, 33 4;

aperture, 7 a. In this specimen the rounding notch of the

aperture is visible.

Localities. — North Woodstock (Cushman Coll, no. 181,

Henderson Coll, no. 63); Saco Lake (B. S. N. H., nos. 4235,

4325); Franconia (B. S. N. H., no. 4307); Pinkham Notch

(B. S. N. H, no. 5148).

Nebela collaris (Ehrenberg).

Test in most of the specimens examined is composed of cir-

cular or ovoid plates, transparent and colorless. Several speci-

mens showed straight or curved longitudinal plates mingled

with the circular ones. One was bent strongly on one side

giving a curved form to the shell.

Size. — Length, 65-196 p; breadth, 44-108 4; aperture,

14—46 p.

Localities. — North Woodstock (Cushman Coll., nos. 176, 178,

180, Henderson Coll., nos. 52, 65); Lake of the Clouds (B. S.

N. H,, no. 4319); Profile Lake (B. S. N. H., no. 4313); Pink-

ham Notch (B. S. N. H., no. 5164); Saco Lake (B. S. N.B,

nos. 4233, 4323); Mirror Lake, Chatham (Cushman Coll., nos.

156, 157).

152 THE AMERICAN NATURALIST. | (Vor. XXXIX.

Nebela flabellulum Leidy.

Test largely composed of circular disks much as in the pre-

ceding.

Sise.— Length, 63-90 a; breadth, 75-100 p; aperture,

18-20 p.

Localities. — Lake of the Clouds (B. S. N. H., no. 4319);

Scribner's Brook, Wakefield (B. S. N. H., no. 4786); Mt.

Moosilauke (Henderson Coll., no. 74).

Arcella vulgaris Ehrenberg.

Test a yellowish or brown chitinoid membrane, with minutely

hexagonal cancellation. The common form of the upper surface

is an evenly rounded dome, but two or three individuals showed

top and sides depressed into bluntly angular facets.

Size. — Length, 42 p; breadth, 23-54 m; aperture, 11-15 p.

Localities. — Mt. Munroe (Cushman Coll, no. 194) ; Saco

Lake (B. S. N. H., nos. 4235, 4323).

Arcella discoides Ehrenberg.

Test of same material as in the preceding, in form more flat-

tened.

Size. — Length, 29-44 p; breadth, 77-108 p; aperture,

19-42 p.

Locality. — North Woodstock (Cushman Coll., nos. 176, 179,

198, Henderson Coll., nos. 54, 64).

Arcella mitrata Leidy.

Test of same material as in the preceding. In form, viewed

either from above or from below, with the circular outline broken

by the salient angles of the strongly marked facets. In side

view, the shell is crown-shaped.

Size. — Length, 63-135 p;. breadth, 67-155 yw; aperture,

34-63 p.

Localities. — Lake of the Clouds

(B. S. N. H., no. 4319);

Pudding Pond, N v

orth Conway (Henderson Coll., no. 79).

No. 459.] WHITE MOUNTAIN RHIZOPODS. 153

Centropyxis aculeata (Ehrenberg).:

Test of yellow or brown chitin as in Arcella. In some of the

specimens examined, quartz grains were incorporated in the

membrane. The form is always characteristic: mouth and

fundus eccentric in opposite directions. The typical form has

several spines crowning the fundus.

Szze.— Greater diameter, 89-153 »; shorter diameter, 66—

93 », aperture, 19—57 u.

Localities — North Woodstock (Henderson Coll., nos. 52, 60,

61); Squam Lake (Cushman Coll, no. 197); Pudding Pond,

North Conway (Henderson Coll., no. 70) ; Intervale (Henderson

Coll., nos. 66, 69) ; Gilmore Pond near Profile House (B.'S. N.

H., no. 4314) ; Claremont (B. S. N. H., no. 4662).

Centropyxis aculeata var. ecornis (Ehrenberg).

As the name implies, the fundus is not crowned with spines.

One specimen examined showed the Arcella-like cancellation of

the shell noted by Leidy (p 183).

Size.— Average length, 48 »; longer diameter, 48-144 u;

aperture, I2—4I y.

Localities — North Woodstock (Cushman Coll., no. 176, Hen-

derson Coll., nos. 53, 62) ; Mt. Munroe (Cushman Coll., nos. 194,

196); Profile Lake (B. S. N. H., no. 4313) ; Franconia (B. 5.

N. H, no. 4307) ; Saco Lake (B. S. N. H., nos. 4325, 4324).

Cyphoderia ampulla (Ehrenberg).

The test in all specimens examined was of similar structure,

and varied comparatively little in size. It isa delicate chitinoid

membrane, colorless or faintly yellow, showing. minute hexagonal

cancellation ; rim of oval aperture finely beaded.

Size— Length, 104-143 4; extreme breadth, 42-50 »; aper-

ture, 14-18 p.

Localities.— North Woodstock (Cushman Coll., no. 189, Hen-

derson Coll, nos. sr, 52, 63); Squam Lake (Cushman Coll.,

no. 198); Lake of the Clouds (B. S. N. H., no. 3719; Profile

154 >. THE AMERICAN NATURALIST. (VoL. XXXIX.

Lake (B. S. N. H., no. 4313); Pudding Pond, North Conway

(Henderson Coll. no. 71) ; Claremont (B. S. N. H., no. 4662).

Euglypha alveolata Dujardin.

Test chitinous, transparent and colorless. Ih form, generally

a regular ovoid shape, truncated at the smaller end. One or

two specimens were narrower and more flask-shaped. About

half of the shells examined had spines.

Size — Length, 48-91 y; breadth, 31-46 p; aperture, I2-

I8 a.

Localities— Profile Lake, Claremont, Franconia, and Saco

Lake (B. S. N. H., nos. 4313, 4662, 4307, 4325).

Euglypha ciliata ( Ehrenberg).

The plates in the tests of the specimens did not seem to over-

lap. In one specimen the cilia were few and long, in the others

more numerous and shorter.

Szze. — Length, 70-78 a; breadth, 37-42 u; aperture, 16-

18 p. These were all found in the valley and show little variety

in size.

Localities.— North Woodstock (Cushman Coll., nos. 176, 181,

Henderson Coll. no. 65); Intervale (Henderson Coll., no. 67) ;

Profile Lake (B. S. N. H., no. 4213).

Trinema enchelys (Ehrenberg).

Closely corresponds to figure ı of Plate 39 of Leidy.

Size. — Length, 81 a; breadth, 44 u; aperture, 16 u.

Locality.— Franconia (B. S. N. Hy no. 4307).

Acanthocystis chztophora Schrank.

But one specimen of this species was found and that was

typical in every way.

Szze.— Breadth with spines, 125 u;

length of spine, 24 p.

Locality. — North Woodstock (Cushman Coll., no. 190).

breadth of body, 54 u;

No. 459.) WHITE MOUNTAIN RHIZOPODS. 155

Besides the recording of the species from this general region,

one further use was made of this material: a comparison was

made with the average measurements of Leidy. The results of

this comparison may best be seen in the following table : —

Leidy-Average.

Aper- per- Aper-

Lgth. Bdth. ture. Lgth. Bdth. ture. Lgth. Bdth. ture.

Difflugia constricta.

Intervale 178 117 49 Mt. Munroe 68 37 15 320 no 68

Nebela collaris.

Squam Lake 102 75 37 Lakeofthe Clouds 80 59 22 161 135 —

Arcella mitrata.

North Conway — .155 63 Lake of the Clouds — 7 34 = 142 56

Centropyxis ecornis.

North Woodstock — 83 34 Mt. Munroe — 59 28 — 146 64

From the above table, which represents the conditions seen

in almost all the species under observation, the difference in

size between the average measurements of Leidy for the whole

of North America and the average measurements for this region

is at once apparent. That this is due rather to latitude than

altitude it seems safe to infer as the valley lakes are no higher

than many of the medium records of Leidy. If it is safe to

draw a conclusion from this, it at least seems to indicate that

these animals are as a rule smaller in higher latitudes than in

lower. Such a conclusion, of course, cannot be of great weight

unless worked out in other cases, but is at least indicated here.

The other point which seems much more certain by direct

comparisons in this same general locality is that some species

are smaller on the tops of the mountains than they are in the

valleys of the same region. In the first column are given the

measurements of typical valley specimens and in the second

column the measurements of specimens of the same species

from lakes of about 5000 feet altitude. The differences in this

case are at once marked and definite and it may be said with

every degree of certainty for the species here worked out that a

species at high altitudes will be smaller than the same species

in lower altitudes of the same region. This one fact seems to

repay the time spent in working up the various lots of material.

CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF

THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD

COLLEGE. E. L. MARK, DigECTOR. NO 162.

THE REACTIONS OF THE POMACE FLY (DROS-

OPHILA AMPELOPHILA LOEW) TO LIGHT,

GRAVITY, AND MECHANICAL

STIMULATION.

FREDERIC W. CARPENTER.

THE observations which this paper records were made on the

movements of the common pomace or little fruit fly, Drosophila

ampelophila Loew. Insects of this species can be collected in

abundance in the autumn, and a culture can easily be maintained

in the laboratory all winter if it is kept supplied with decaying

fruit such as bananas or apples. The eggs are laid in this

material, which later is used by the larvae as food. ;

When a large cylindrical glass vessel containing a stock cul-

ture of these flies was placed on a table near a window, it was

noticed that the flies accumulated in the greatest numbers on

the upper part of the side of the vessel nearest the window.

This indicated that they were positively phototropic to ordinary

daylight, and probably negatively geotropic, although it seemed

possible that their position near the top of the vessel might have

been due to the fact that, owing to its position near the bottom

of the window, the vessel was illuminated more brightly above

than below. It was also observed that when the vessel was

exposed to direct sunlight the flies, after a time, tended to

accumulate, not on the surfaces toward or away from the win-

dow, but in intermediate positions on the two sides. Here the

majority remained quiet in the regions of least illumination. A

similar observation was made by Loeb (’93) on planarians, which

157

158 THE AMERICAN NATURALIST. [VoL. XXXIX.

gradually came to rest in the darker portions of a shallow cylin-

drical glass vessel placed before a window. The large majority

of the flies resting thus on the vertical sides of the vessel had

their long axes parallel to the light rays, and their heads turned

away from the source of light. Parker (:03) has pointed out that

the mourning-cloak butterfly, coming to rest in bright sunlight,

also places itself with the head away from the sun. The posi-

tion assumed by the flies under these conditions might have led

to the supposition that they had become negatively phototropic

through continued exposure to an intensity of light higher than

that to which they were accustomed. Such reversals have been

observed for barnacle larvae by Groom und Loeb (’90), for

Hydra by Wilson (91), for Polygordius larvae by Loeb ('93),

for Limax by Frandsen (:or), for copepods by Parker (:02)

and for earthworms by Adams (:03). However, it was found

that upon slightly turning the vessel on the table nearly every .

fly flew instantly toward the window, thus giving marked evi- -

dence of positive phototropism.

The experiments about to be described were undertaken with

a view to obtaining some definite quantitative statements as to

the influences of light and gravity on the movements of the

organisms; and most particularly was it desired to test the

responses of the flies to a range of high intensities of light.

For valuable advice and aid in devising the apparatus and con-

ducting the experiments the writer is indebted to Professor

G. H. Parker, under whose supervision the work was carried on.

Apparatus — In all of the operations the flies were confined

in a cylindrical glass vessel measuring 15 cm. in length and 5

cm. in diameter, and closed at both ends by glass caps. Around

the outside of the vessel were placed five small rubber bands at

equal distances apart, the cylinder being thus divided into six

sections each 2.5 cm. long. This subdivision of the vessel by

‚surface markings enabled the observer to record the position of

the contained fly at any moment with considerable precision.

In some of the experiments a dark box of convenient size was

used, a sectional plan of which is given in the accompanying fig-

ure. This box was lined throughout with black cloth. In the

center of each end wall was fixed an incandescent electric-light

No. 459.] REACTIONS OF POMACE FLY. 159

bulb (L.), which projected into the interior. A determination

of the amount of light given off from the ends of these bulbs

showed each to have a candle power of approximately 5. The

lighting of both these bulbs could be controlled from the out-

side by means of keys. A window let into one side of the box

gave access to the interior when desired. This window could

indicate the division into six sections by rubber ;

roken line surrounding V isa projection of the outline of the window of the dark

box on the plane of this drawing. : x

be closed by a tight-fitting shutter. When the dark box was

used the glass cylinder (V.), containing the flies, was placed

within, midway between the free ends of the two electric-light

bulbs, its axis coinciding with the straight line connecting these.

The distance from either end of the cylinder to the adjacent

electric light filament was 7 cm. Between each bulb and the

cylinder was inserted, as a heat screen, a glass vessel (W.), filled

with water, and having flat, vertical sides 3 cm. apart. Both

the glass cylinder and the heat screens rested on strips of wood

painted black; and these supports could be so arranged that

the box, with cylinder and heat screens in place, could be used

in either a horizontal or a vertical position.

Kinetic Effect of Mechanical Stimulation.— If in ordinary

daylight a fly be placed in the glass cylinder, and this be held

vertically, the fly will seek the top. If now the vessel be turned

upside down the fly, finding itself at the bottom, will creep up-

ward again to the top within considerably less, as a rule, than

160 THE AMERICAN NATURALIST. [Vor. XXXIX.

one minute. In order to ascertain the behavior, under similar

conditions, of flies deprived of light, both when allowed to

remain quiet and when mechanically stimulated, the following

experiment was undertaken, using the glass cylinder, but not the

dark box described above.!

Two or three flies, the largest number easily worked with at

one time, were put into the cylinder, and while exposed to day-

light allowed to pass to its top section, whereupon it was quickly

covered in such a way as to exclude all light, and the ends imme-

diately reversed, the section containing the flies being thus made

the bottom one. After having been left undisturbed for two

minutes the cylinder was uncovered, and the positions of the

flies on the sides of the vessel recorded. When they had again

reached the top the vessel was placed in the dark again by steps

similar to those just described, vzz., with the flies in the bottom

section. At the end of one minute, however, the whole appa-

ratus was this time revolved on the table top with friction for

forty seconds so that the flies were mechanically agitated. Then

after twenty seconds of quiet — making in all two minutes in

darkness — the cover was removed, and the positions of the

flies recorded as before. Periods of quiet in the dark were thus

made to alternate with periods involving jarring until five read-

ings for each set of flies had been made. Table I gives the

combined records for three females and two males, the figures

indicating the number of flies discovered in the sections of the

cylinder at the end of two minutes in darkness. Section No.

I is the uppermost, section No. 6 the lowest.

The table shows that the flies allowed to remain undisturbed

were found in 16 instances in the lower half of the cylinder,

and in 9 in the upper half, only 2 of these being in the top sec-

tion; while those flies which were mechanically stimulated were

distributed ro in the lower half and 15 in the upper half, 7 of

the latter number being in. the top section.

! It might be mentioned here that throughout the observations male and female

flies showed no consistent differences in their reactions.

No. 459.] REACTIONS OF POMACE FLY. 161

Table I.

Distribution of five flies in a vertically placed glass cylinder after two

minutes in darkness; the flies at the outset occupied the bottom section of

the vessel, No. 6.

en Numbers of trials. Totals.

Without mechanical stimulation.

I 2 3 4 5

I I I 2

2 I I 2 4

3 I 2 3

4 o

5 3 I 3 7

6 2 I a 3 E

With mechanical stimulation.

I 2 3 4 5

I I I 2 3 4

2 2 I I 2

3 1 1 :

4 1 :

5 1 I :

6 I 2 I 2 I 7

Apparently, then, mechanical stimulation tends to induce the

locomotion which results in this upward migration, or, in other

words, it has a kinetic effect on the organisms. The direction

of the movement indicates a negative response to gravity, a

reaction which is more strikingly demonstrated in a succeeding

experiment. The lesser degree of activity shown by the flies

allowed to remain quietly in the darkness recalls the experiment

of Loeb (’90) with plant lice, in which continued confinement in

a dark chamber brought on a kind of “ dark rigor " (*Dunkel-

starre’’). Jo

Kinetic Effect of Light.— To test the possible kinetic influence

of light the following experiment was tried. The glass cylinder,

containing a single fly, was placed in a vertical position 1n the

162 THE AMERICAN NATURALIST. [Vor. XXXIX.

dark box, with an incandescent electric-light bulb at either end.

The lower light only was at first turned on, and the fly thus

attracted into the lower section. Then the window of the box

was closed, the light turned out, and the fly left for one minute

in darkness. At the end of this period both the upper and lower

lights were turned on simultaneously, and at the expiration of

another minute the window was opened and the position of the

fly noted. Five readings were taken in this manner for each of

six flies, three males and three females. When the results were

combined (see Table II) it was seen that, out of a total of 30

readings, the flies had been detected 19 times in the upper half

of the cylinder, no less than 16 of these observations being for

the topmost section. In 11 cases the flies had remained below

the middle of the cylinder.

Table II.

Distribution of six flies in a vertically placed glass cylinder after one

minutes exposure to equal illumination above and below: the fies at the

outset occupied the bottom section of the vessel, No. 6.

Sections of :

cylinder. Number of trials. Totals.

I 2 3 4 5

I 2 2 5 4 3 16

2 2 o o I o 3

3 o o o o o o

4 o o o I o I

5 o I o o o I

6 2 3 I o 3 9

When this distribution is compared with that for flies left

undisturbed in darkness for an equal length of time (Table I),

it would appear that light acts as a stimulant to locomotion ;

and the rather striking efficiency of light in this respect is

attested by the comparatively large number of flies found in the

uppermost section of the cylinder.

Directive Effect of Light. — Experiments to demonstrate the

directive effect of light of moderate intensity may be thought to

No. 459.) REACTIONS OF POMACE FLY. 163

have been scarcely necessary since under natural conditions

Drosophila gives such unquestionable evidence of positive pho-

‘totropism. However, in order to obtain a more detailed ex-

pression of this, and to make the observations more complete,

the glass cylinder, again containing a single fly, was placed hori-

zontally in the dark box, and the lights on the right and left

were alternately turned on and off. By this arrangement the

influence of the light was brought to bear on the insect at right

angles to the influence of gravity, which could not, therefore,

affect the results. The window in the side of the dark box

was left open in order that the movements of the fly might be

watched. At the beginning of the experiment, when the insect

was in the section of the cylinder the farthest to the left, the

right light only was turned on. The fly would then creep

toward the right along the sides of the cylinder. The time of

the excursion from the line bounding the last section on the left

to the one bounding the last section on the right was taken with

a stop watch. As soon as the fly had crossed the last line on

the right, the light at that end of the box was turned off, and

the left light turned on. This change in the direction of the

illumination was followed by a progression to the left on the part

of the fly, an active insect setting out on the return excursion

within an average time of about 10 seconds. The progress of

the fly toward the left was also timed by the watch. Thus, by

reversing the lights, the animal could be made to travel back

and forth in accordance with the changes in the direction of

the illumination. Flying responses occasionally took place, but,

since these were difficult to time, they were not taken into

account. Moreover, by neglecting these the records were kept

homogeneous in that they were made for creeping excursions

only. Individual insects differed considerably in the degree of

activity they displayed, and often the same insect would respond

less promptly at one time than at another. On those occasions

when the kinetic influence of the light seemed for. some Teason

to be partially inhibited, recourse was had to mechanical stim-

ulation to bring the animal into a more active state. This was

effected by removing the glass cylinder from the dark box and

shaking it. Flies thus treated usually reacted more readily to

the light rays for some time after.

164 THE AMERICAN NATURALIST. | (Vor. XXXIX.

In all, four flies, two males and two females, were used in this

set of experiments. Each fly was sent five times in each direc-

tion. The average time for twenty creeping excursions toward

the light from left to right, a distance of 10 cm., was 7 65 866;

from right to left, 7.71 sec. The average rate in either direc-

tion was accordingly about the same, 1.3 cm. per sec. That

Drosophila possesses the character of positive phototropism is

obvious.

Directive Effect of Gravity.— By arranging the apparatus used

in the phototropic experiment just described so that the glass

cylinder had a vertical position, it was possible to test the

directive effect of gravity on flies stimulated to action by light.

The incandescent lamps were now situated one at the upper and

one at the lower end of the cylinder, and alternately turned on

and off. By means of a stop watch, time records of excursions

along the vessel were taken as before. Not all the flies tested

responded readily to the light, and preliminary mechanical stim-

ulation produced by shaking the cylinder was sometimes resorted

to. Finally two active male insects were found, for each of

which five readings were obtained for each direction. The aver-

age time for ten creeping excursions toward the light from the

bottom to the top of the cylinder through a distance of 10 cm.

was 6.2 sec., or at a rate of 1.61 cm. per sec. ; from the top to

the bottom, 44 sec. or at a rate of 0.23 cm. per sec. The flies

crept upward quickly and continuously, and at a rate slightly

more rapid than that of flies in the cylinder placed horizontally.

In their course downward they frequently stopped for short

intervals.

The response to gravity accordingly appears to be a negative

one, as was indicated by the behavior of the insects when

mechanically stimulated in the dark. In the rapid upward

excursions positive phototropism and negative geotropism coin-.

cided. In the slow downward ones these two influences were

opposed, and although the directive influence of the light proved

the stronger, the retarding effect of the opposed influence of

gravity was apparent in the strikingly reduced rate of progres-

sion.

It happened occasionally that an insect would fly through a

No. 459.) REACTIONS OF POMACE FLY. 165

portion of its excursion and alight on the vertical side of the

cylinder. When this occurred the fly came to rest with its head

uppermost, no matter whether its flight had been directed

upward or downward. This orientation of the body on alighting

may have been due to negative geotropism.

Effect of Increased Intensities of Light — In order to subject

the flies to light of different intensities use was made of an arc

light suspended at one end of a dark room with dead black

walls. The glass cylinder containing a single fly was placed

horizontally on a small movable table, one end of the cylinder

being directed toward the light. The movements of the fly were

observed while the end of the cylinder through which the rays

fell was at four different distances from the arc light, vis., 800

cm., 300 cm., 80 cm., 40 cm. The candle power of the arc light

used was approximately 64. Between the cylinder and the light

a rectangular glass vessel containing 3500 cc. of water was inter-

posed as a heat screen. The front and back walls of this vessel

were 7 cm. apart.

At each of the four positions the responses of the fly were

timed as follows. A small opaque screen was set up between

the arc light and the cylinder, and at the opposite end of the

cylinder an incandescent lamp was turned on. The fly, attracted

by the light of the lamp, crept toward it. At the moment the

insect reached the middle of the cylinder the screen obscuring

the arc light was removed, the incandescent light extinguished,

and the stop watch started. The fly, headed away from the arc

light, usually stopped momentarily when suddenly exposed in

this manner to the light from behind, and then resuming its

course moved on until the opposite (dark) end of the cylinder

was reached. Here it turned and hastened toward the illumi-

nated end, either by creeping, or by flying, or by both creeping

and flying. With the cylinder close to the arc light the fly

sometimes turned about immediately upon the removal of the

screen. When the fly crossed the boundary line of the section

nearest the arc light the watch was stopped and the time

recorded. At distances of 800 and 300 cm. a large majority of

the responses were of the creeping kind. At positions nearer

the light the insect often flew through a part of the distance —

166 THE AMERICAN NATURALIST. | (Vor. XXXIX.

sometimes through the entire distance. Since it was impossible

to obtain pure creeping responses in all cases, those involving

both creeping and flying were taken into account. Pure flying

responses were not timed.

Observations were made on four flies, two males and two

females, and the average time of twenty responses (five for each

fly) at each of the four distances from the arc light was

obtained. At 800 cm. and 300 cm. and even at 80 cm. the

results did not materially differ, the average times of the

responses at these three positions being respectively, 18 sec.,

I8 sec., 16.7 sec. At 40 cm. there was a marked increase in

the rapidity of the movements of the flies, the average time

of the responses being 7.4 sec.

The behavior of a fly under continued exposure to the highest

intensity of light available for these experiments seemed to be

of considerable interest. The apparatus used was the same as

for the experiments last described, except that an arc light of

greater candle power (250 c. p. approx.) was used. The pro-

cedure was also unchanged, the insect being brought up from a

distance of 300 cm. to 80 cm. and finally to 40 cm. from the

light. For each of the first two positions time records for five

excursions were obtained, although those for 80 cm. required

patient manipulation and many repetitions of the excursions, so

numerous did the flying responses become. At 40 cm. the

behavior of the fly was such that a full set of five readings

could not be taken. Under the influence of the intense light

the insect became extremely active, flying and leaping about

spasmodically in all directions, and giving little or no evidence of

directive responses. That is to say, the directive influence of

the light was no longer effective enough to cause the fly to make

excursions back and forth along the cylinder in accordance with

the position of the illumination. While the fly was in this con-

dition of great muscular activity, the screening off of thearc light

and the turning on of the incandescent lamp, were followed by

less activity on the part of the animal, but not by a progression

toward the illuminated end of the vessel. The directive influ-

ence seemed to be for the time inhibited.

It appears, then, that continued exposure to a high intensity

No. 459.] REACTIONS OF POMACE FLY. 167

of light produces very rapid locomotor movements, but while the

kinetic effect of the light is thus increased, its orienting effect

may be strikingly diminished. Throughout the experiments

with high intensities there was no evidence of a change from

positive to negative phototropism even under the influence of the

highest intensity employed, that of a 250 c. p. arc light at a

distance of 40 cm.

Discussion of Results.— In the preceding pages it has been

found convenient to distinguish between two factors in the effect

of light on Drosophila, a kinetic factor and a directive one.

These two factors undoubtedly give rise to different kinds of

responses, yet they are so closely related that it may be well to

lay some stress on their interdependence. The directive effect

of light manifests itself only in connection with a kinetic influ-

ence sufficient to induce locomotion. The insects while at rest

do not regularly lie with their heads directed toward the. source

of illumination ; in fact, those flies of the stock culture already

referred to, which, after continued exposure to direct sunlight,

came to rest in the least brightly illuminated portions of the

vessel, were found with their heads turned away from the win-

dow. In the experiments with incandescent lights the turning

on of one of the lamps was rarely if ever followed by mere ori-

entation on the part of the fly, z. e., simply an adjustment of the

body in such a manner that its long axis became parallel with

the light rays and that both eyes received an equal amount of

light, — a condition of symmetrical stimulation which Loeb (97)

has maintained to be the essential factor of orientation. While

the muscle reflexes necessary to put the insect in this position

were usually forthcoming under such stimulation, these move-

ments proved to be initiatory locomotor movements, being con-

tinuous with the series of locomotor reflexes which followed.

When, on account of light-fatigue or other causes, the insect

ceased moving about, no satisfactory evidence of orientation

either to light or to gravity could be adduced from the position

the animal assumed.

In the case of one fly subjected to the influence of a very high

intensity of light, a reaction was obtained which involved only

the kinetic factor. This fly while stimulated to great activity

168 THE AMERICAN NATURALIST. (VoL. XXXIX.

did not appear longer to respond to the directive influence. Its

movements were hap-hazard, not guided by the direction of the

light, as if the organism, in its state of extreme excitement, had

lost for a time its tendency to place itself when in motion under

conditions of symmetrical stimulation. This violent” kinetic

effect of very intense light has been observed for several lower

organisms by Pearl and Cole (:02). The conditions of their

experiments did not permit them to note the effect on orienta-

tion. Long exposure produced a paralyzing effect, so that the

movements became more and more slow as the stimulus con-

tinued to act. No insects were tested by them.

The experiments with the 64 c. p. arc light made it clear that

when the intensity is increased by lessening the distance of the

light from 80 cm. to 40 cm. there is a marked increase in the

rapidity of true phototropic responses. This result in the case

of Drosophila is certainly not due merely to more precise orien-

tation, as was suggested by Davenport ('97) to explain the

increase in the rate at which Daphnia traveled under strong

light. Itisinteresting to note that Yerkes (: 00), experimenting

on the same organism (Daphnia), concluded that while the

increase in rate depended chiefly upon precision and quickness

of orientation, there was also evidence of a quickening of the

“swimming motions.

It was stated at the beginning of this paper that when the

insects are exposed in a large cylindrical glass vessel, to direct

sunlight from a window, many of them eventually come to rest

on the sides of the vessel which are least illuminated. Their

heads are in this instance directed away from the source of

light. When disturbed by the vessel's being turned about they

show positive phototropic responses by flying toward the light.

This apparent negative orientation while at rest is not due,

therefore, to a reversal of the directive influence of the light

owing to continued exposure to a higher intensity.

It seems probable that the behavior of the flies under these

conditions is the result of the following causes. When first

exposed to the strong kinetic influence of bright sunlight Droso-

phila becomes very active. Its flying and creeping movements

toward the light are limited by the wall of the vessel, and the

No. 459] REACTIONS OF POMACE FLY. 169

continued locomotor reflexes bring it into other regions. It may

by accident reach the vertical surfaces of the vessel intermediate

between the surface nearest and the one farthest from the win-

dow. Here the kinetic influence of the light, owing to decreased

intensity, is least. The fatigued fly may still, however, be stim-

ulated sufficiently to cause it to creep or at least to turn about.

If it chances to place itself with the head directed away from the

window, the reduced light stimulus received by the eyes may be

inadequate to call forth further muscle reflexes, and the fly re-

mains quiet in this position. Jarring the insect, or turning the

vessel about so that more light enters the eyes, may increase the

kinetic stimulation to such an extent that renewed movements

are induced.

In Drosophila just as light causes locomotion, so mechanical

stimulation seems to bring about progressive movements. From

the nature of the case this stimulus was very roughly applied in

the foregoing experiments, there being no effort to limit its

application to one side of the body with a view to detecting its

directive effect, if any, under such conditions. On the other

hand, an allied form of stimulus, the pullof gravity, directs the

movements of the organism, although it does not appear to

induce them. A condition of symmetrical stimulation is un-

doubtedly brought about when, on a vertical surface, the fly places

its long axis parallel to the direction of the lines of the earth's

attraction. This pull of gravity on the materials which make up

the animal's body differs more in degree than in kind from the

impact of surrounding objects to which the animal is subjected

when mechanical stimulation is applied. If the attraction of

gravity and mechanical stimulation are regarded, then, as closely

allied forms of stimuli, their two effects upon the organism

admit of an almost exact comparison with the two effects of

light. When left quietly in darkness, Drosophila gives little

evidence of a tendency either to orient itself, or to move

about. Thus gravity alone seems insufficient to induce either

of these responses. When, however, the insect is mechan-

ically stimulated, locomotor movements do ocour, and in con-

nection with them the directive influence of gravity becomes

effective. The animal orients itself with its head away from

170 THE AMERICAN NATURALIST. (VoL. XXXIX.

the center of the earth, and, responding to the kinetic influence

of mechanical stimulation, moves upward. The general result

is a progression in a definite direction, precisely such as is

obtained when a light is placed at one end of a horizontal glass

cylinder containing the insect.

Summary of Results.— 1. Mechanical stimulation has a

kinetic effect upon Drosophila, since it induces locomotion.

2. Gravity has a directive effect upon the active insect, which

is negatively geotropic, that is, the insect moves away from the

center of the earth.

3. Light has both a kinetic and a directive effect. The insect

moves toward the source of light, being positively phototropic.

The directive effect is apparent only when the kinetic stimulus is

sufficient to induce locomotion.

4. The exposure of Drosophila to light of high intensity is

accompanied by an increase in the kinetic effect. Under the

influence of the highest intensity used, that of a 250 c. p. arc

light at 40 cm., the muscle reflexes of an insect become very

rapid and violent, and the directive influence of the light seems

inhibited. There is no indication of a reversal of the directive

influence from positive to negative. ^

5. After continued exposure to direct sunlight in a large

cylindrical glass vessel many insects come to rest in the least

brightly illuminated regions and with their heads away from the

source of light. This is not an indication of negative pho-

totropism. The fatigued insects remain quiet in this position

because it is the one in which the least light enters the eyes,

and in which, as a consequence, the kinetic stimulus is least.

No. 459.] REACTIONS OF POMACE FLY. 171

BIBLIOGRAPHY.

ADAMS, G. P.

:03. On the Negative and Positive Phototropism of the Earthworm

Allolobophora foetida (Sav.) as determined by Light of Different

Intensities. Amer. Jour. Physiol., vol. 9, no. t, pp. 26-34.

DAVENPORT, C. B.

'97. Experimental Morphology. Part First: Effects of Chemical and

Physical Agents upon Protoplasm. New York, xiv + 280 pp.

FRANDSEN, P.

:01. Studies on the Reaction of Limax maximus to Directive Stimuli.

Proc. Amer. Acad. Arts and Sci., vol. 37, pp. 185-227.

Groom, T. T., und LoEp, J

'90. Der Heliotropismus der Nauplien von Balanus perforatus und die

periodischen Tiefenwanderungen pelagischer Tiere. Biol. Cen-

tralb., Bd. 10, No. 5-6, pp. 160-177.

LOEB, J.

'90. Der Heliotropismus der Thiere und seine Uebereinstimmung mit

dem Heliotropismus der Pflanzen. Würzburg, 118 pp.

LoEB, J.

'93. Ueber künstliche Umwandlung positiv heliotropischer Thiere in

negativ heliotropische und ken c nde Arch. f. ges. Physiol., Bd.

54, Heft 1-2, pp. 81-107.

LOoEB, J.

'97. Zur Theorie der physiologischen Licht- und Schwerkraftwirkungen.

Arch. f. ges. Physiol., Bd. 66, Heft 9-10, pp. 439-466

PARKER, G. H.

:02. The Reactions of Copepods to Various Stimuli and the Bearing of

this on Daily Depth Migrations. Bull. U. S. Fish Comm. for

19OI, pp. 103-123.

PARKER, G. H.

:03. The Phototropism of the Mourning-cloak Butterfly, Vanessa antiopa

Linn. Mark Anniversary Volume, pp. 453-469, pl. 33-

PEARL, R., and COLE L. J. :

:02. The Effect of very Intense Light on Organisms. Report Mich.

Acad. Sci. for 1901, pp. 77-75

WItson, E. B. .

'91. The Heliotropism of Hydra. Amer. Nat., vol. 25, no. 293, pp.

413-7433.

YERKES, R. M.

:00. Reactiuns of Entomostraca to Stimulation by Light. II. Reac-

tions of Daphnia and Cypris. Amer. Jour. Physiol., vol. 4, no.

8, pp. 405-422.

NOTES AND LITERATURE.

GENERAL BIOLOGY.

Le Dantec’s Treatise on Biology.' — The author of this consid-

erable volume is well known from a number of general treatises of a

popular nature all. characterized by an agreeable style, but written

rather freely, not to say speculatively; that is, not based at every step

on ascertained fact. His works are what we are accustomed to think

of as typically French, as opposed to the typically German treatises

that build up a science out of numberless bricks of recorded observa-

tions (all fully referred to bibliographically) laid down in orderly

fashion.

Le Dantec’s volume is readable but not epoch-making. In places

it introduces the reader to the very latest ideas— as in the sugges-

. tive chapter (V) on The Generation with Chromosomes and Sexual

Parasitism. In other places it seems to bring us back to an earlier

age, as in the discussion of the formation of species — species being

defined as groups whose hybrids are sterile.

The author treats of many things, as a glance at the Table of

Contents shows: chemical activity in a liquid plasm; assimilation ;

chemical and histological complexity; sexuality ; sexual parasitism ;

heredity ; acquired characters; amphimixis; the determination of

somatic sex; life and death; the formation of species; histological

differentiation of Metazoa ; parallelism of psychology and physiology ;

and, lastly, “la liberté et l'égalité" among animals.

The book is clearly written and will be read by many interested

in semispeculative biology based, for the most part, on recent knowl-

edge; but considering its lack of bibliographic citations and its

somewhat glib treatment of difficult subjects it cannot be considered

indispensable to the worker.

C.H D.

Organic Evolution.?— The author states in his preface that this

! Le Dantec, Felix. Zyaité de Biologie. Paris. Alcan, 1903. 8vo, 553 PP-

IOI figs. in text. 15 fran

* Metcalf, M. M. ye ilies of the Theory of Organic Evolution, with a

na of some of the Phenomena which it explains. New York. Macmil-

an Co., 1904. Svo, xxii + 204 pp., 143 pls., and 46 text-figs.

173

174 THE AMERICAN NATURALIST.: [Vor. XXXIX.

book *is not intended for biologists, but rather for those who would

like a brief introductory outline of this important phase of biological

theory.” Nevertheless it will doubtless prove a very useful work in

the hands of beginners in biology and of the “nature-study " teacher,

and is sure to be attractive to the general reader because of the

wealth of illustrative material which it contains. This material has

been selected with great care and forms an integral part of the work.

It is one of the best of the popular treatises on evolution.

WE b.

BOTANY.

Plant-Breeding.' — This useful and deservedly popular hand-

book, originally published in 1895, now appears in a third edition,

revised so as to cover the important period since 1900, when Mendel's

law was rediscovered. The work meets the needs of a wide circle

of readers, including the general public particularly interested at the

present time in the subject of horticulture, the practical plant-breeder,

and the student. To the student the extensive bibliography appended

to the book will be especially valuable.

WEC

Haberlandt’s Physiological Anatomy of Plants.?

twenty years since the first edition of this work appeared and despite

the mass of new material which has accumulated in that time, the

author is able to adhere to his original plan in the exposition of the

structures and functions of plant tissues. There is, indeed, not so

much difference between this third edition and the second published

in 1896, as there was between the last named and the first imprint of

1884. Nevertheless there is a considerable amount of new material,

as is shown by the fact that the number of pages has increased from

550 to 616, and that the illustrations number 29 more in the new

edition.

"Bailey, L. H. Pram- i ind five Lectures upon the Amelioration of

Domestic Plants. New Yor millan Co., 1904. 16mo, 3d edition. xiii +

334 pp-, frontispiece and 20 ext

* Haberlandt, G. Physiologische Pflanzenanatomie. Leipzig. Engelmann, 1904.

8vo, 3rd dition: xvi-+ 616 pp., 264 figs. in text.

No. 459.] NOTES AND LITERATURE. 175

It is near the end of the book that the greatest change is to be

noticed. In place of the eleventh chapter on tissues for special

functions, we find the subject augmented to three chapters as follows :

tissues for movement, sense organs, and tissues for conducting stim-

uli. In the first is an account of the passive hygroscopic movements

of certain plant parts, and of the active movement, as seen in pul-

vini, stamens, etc. In the second is an elaborate treatment of the

statolith theory, as well as descriptions of various forms of sensitive

hairs and papilla. In the third part the writer considers the propa-

gation of stimulus in Mimosa, and in his explanation adheres to his

former point of view. Here also he gives an account of inter- and

intra-cellular conduction of stimuli.

Haberlandt's treatment of anatomy well deserves the prefix physi-

ological, and stands, as it is intended to, in striking contrast to the

mere topographical anatomy of many other writers. Any hard and

fast system must naturally have a narrowing influence and a too

ready acceptance of all the classifications of tissues and interpreta-

tions of functions in Haberlandt's book would no doubt lead the

reader into the sloughs of teleology. We can however make what

reservations we wish in his causal explanations and still have left a

wonderfully suggestive and stimulating analysis of the aspects of

plant tissues, viewed from a functional standpoint. That the author

may at times carry this idea of the purposeful development of tissues

too far, cannot be denied, yet even this is better than a purely formal

treatment of the subject from a regional standpoint only. At least

there is impressed upon the reader that plant tissues have functions,

and that these functions constitute a real interest in the study of

anatomy. In these days of increased interest in physiological prob-

lems and of the advance in knowledge of physiological processes,

such a book as this will come more and more into consideration.

The physiologist and ecologist, whether or no they always agree

with the author, must frequently have occasion to consult the book

and it may be suggested that the topographical and phylogenetic

anatomist would do well to pay greater attention to Haberlandt's

point of view.

There is one thing omitted from the book which should perhaps

have found place, namely, a closing chapter by way of a general

summing up of the inter-relations of the various “systems,” so iet 3

more complete picture of the plant as a whole might be obtained.

The section of half-a-dozen pages in the first chapter, in which the

physiological efficiency of the tissues is treated, does not fill the

I 76 THE AMERICAN NATURALIST. [Voı. XXXIX.

want, which could best be supplied at the end, after all the types of

tissues had been taken up. Possibly the author has purposely left

the reader to construct for himself this picture of the plant as a

whole.

The appearance of a book as valuable as this in a foreign

language, always brings with it a certain regret when there is no

similar work available in English. Excellent as it is, the translation

of DeBary’s anatomy is now very far behind the times and there is

no other detailed account of plant anatomy in our language. In

common with many others we hope that a translation of this third

edition of Haberlandt's work will not be long in forthcoming.

H. M. R.

British Fresh-water Alga.! — In his treatise on the British Fresh-

water Alge, G. S. West gives a general view of this group, based

largely upon his own studies of the British Algæ. The great changes

that have been made in recent years and the consequent limiting of

the usefulness of previous monographs is noted. The need of a

monograph of the fresh-water Algz which may be used to determine

the genera and species is also called to one's attention. The book

contains many new facts concerning life histories, development, and

relationships of the Algae. It is illustrated by a large number of text-

figures most of which are original and the localities from which the

specimens were taken are noted. The Peridinez and Characez are

left out as not being certainly true Alga. Besides a short preface,

there is an introduction in which, after disposing of the historical

considerations, the author discusses the occurrence, collection, pres-

ervation, and cultivation of the Algz. Another chapter is devoted to

a brief consideration of the six classes of the fresh-water Algz, their

vegetative, asexual and sexual reproduction, polymorphism ; and the

remainder of the chapter is given over to a discussion of the phylog-

eny and classification, which is based on the latest work on the various

groups. The main portion of the book deals with the various classes,

orders, and families, with a full description of each genus. Asa rule.

each genus is illustrated, often by more than one species. Under

each genus are brief notes and accurate measurements of the British

species most frequently met with. The work recognizes the law of

priority in dealing with the names of the genera, thus tending to fix

in general use certain older but much less generally used names.

LAC.

1 West, G.S. British Fresh-water Alge. Cambridge Biol. Series, Cambridge

Univ. Press, 1904. 8vo, xv + 373 pp., 166 figs. in text. 6

No. 459.] NOTES AND LITERATURE 177

British Desmidiace@.!— There has lately appeared the first

volume of the Monograph of the British Desmidiacee by W. West

and G. S. West. This is the third monograph that has been writ-

ten on British desmids. The first was by Ralfs, in 1848, the second

by Cooke, in 1887, the latter being mainly a compilation. Since

the publication of Cook's work there have been 400 species and 402

varieties added to the desmid flora of Great Britain. The present

volume is prefaced by a brief historical account. A very full bibli-

ography takes up the twenty pages preceding the introduction. In

the introduction a very complete general account of the family is

given, especial attention being paid to the cytological characters. A

number of pages are devoted to the discussion of the following

points: variation, locomotion, vegetative, asexual and sexual repro-

duction, phylogenetic relationships, occurrence and distribution,

collection and preservation, examination and specific determination.

A diagrammatic table is given showing the phylogeny as worked out

by the junior author a few years ago, The arrangement of the

genera follows this scheme and an analytical key is given to all the

genera recognized on this basis. This includes thirty-one genera,

five of which have not been found in the British Isles. The remain-

der of the volume is given up to the systematic treatment of twelve

genera, concluding with Tetmemorus. Under each species or

varietal name appear the following points: a short synonymy, brief

diagnosis including the zygospore, when known, and the range of

measurements, the British localities grouped under England, Wales,

Scotland, and Ireland, the geographical distribution as far as known,

followed usually by certain critical remarks. Asa rule the tendency

seems to be to reduce the number of species and varieties instead of

to increase, as is usually the tendency. One new species, Mesotenium

truncatum, and several new varieties are described. The volume is

illustrated by thirty-two plates, containing about six hundred figures,

of which most are original and many are colored. qe

! West, W., and West, G. S. Monograph of the British Desmidiacea, Vol. 1.

London, Ray Society, 1904. 8vo, xxxvi + 224 pp. 32 pls.

(No. 458 was issued March 23, 1905.)

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VOL. XXXIX, No. 460 . APRIL, 1905

THE

AMERICAN

NATURALIST

A MONTHLY JOURNAL

DEVOTED TO THE NATURAL SCIENCES

IN THEIR WIDEST SENSE

CONTENTS

Page

I. Birds of the Isle of Pines 0. BANGS and W. R. ZAPPEY 179

U. Studies on the Plant Cell.— V PE) . DR. B. M. DAVIS 217

HI. Correspondence . ; ; eaten he Se IE NUT

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THE

AMERICAN NATURALIST.

VoL. XXXIX. April, 1905. No. 460.

BIRDS OF THE ISLE OF PINES.

OUTRAM BANGS AND W. R. ZAPPEY.

INTRODUCTION.

Tue following account of the birds of the Isle of Pines is,

for the most part, based on a large collection and field notes

made by one of us (Zappey) in the spring and early summer of

1904. Zappey had, however, visited the island once before —

in March, 1902 — and the few birds, mostly North American

migrants, taken on that trip that were not observed on the

later one, are included. In addition to this material, William

Palmer and J. H. Riley, who spent two weeks in July, 1900,

near Nueva Gerona, have most kindly placed in our hands their

notes and lists of birds observed and taken. And lastly, in

` order to make our list complete, we include such species as

were recorded from the island by Poey, by Cory, and by

Gundlach.

Mr. Riley has made many comparisons for us with the

material in the United States National Museum, and has other-

wise done everything in his power to help us, and we here

express our most hearty thanks for all his kindness.

! This first collection, unfortunately, did not remain in this country but went

to the Tring Museum, and thus far has not been reported upon.

179

1,80 THE AMERICAN NATURALIST. (VoL. XXXIX.

LITERATURE.

While no very complete list of the birds of the Isle of Pines

has been published, many references to the ornis of the island

can be found in the writings of Poey, Cory, and Gundlach,

Fic. 1.— Map of the Isle of Pines.

and in the three parts that have already been issued of Ridg-

way's Birds of North and Middle America. The full references

to these works are as follows : —

Felipe Poey, Memorias sobre la Historia Natural de la Isla

de Cuba, 1854. |

(Tomo 1, pp. 426-427; a nominal list of birds observed by Gundlach

during a six days' stay at Nueva Gerona.)

C. B. Cory, Catalogue of. West Indian Birds, 1892.

No. 460.] BIRDS OF THE ISLE OF PINES. 181

(Numerous references to the birds of the Isle of Pines, probably from

MSS. furnished the author by Gundlach. The Isle of Pines appears in

the distribution of the various species, usually as Greater Antilles, No. 2.)

Juan Gundlach, Ornithologia Cubana, 1895.

(The last work of this distinguished Cuban ornithologist, containing

many references to the birds of the Isle of Pines.)

Robert Ridgway, The Birds of North and Middle America.

Bulletin of the United States National Museum, No. 50. Part

I, 1901 ; Part II, 1902; Part III, 1904.

(Each species known to the author to occur on the Isle of Pines, is

recorded from there, and in one or two instances measurements are given

for comparison and critical remarks made, as for example in the case of

the Spindalis.)

Fic. 2.— Isle of Pines, as seen from the northeast. The rocky islet in the foreground was the

Tos 1 f ERU ERE PAST t' daf White Ibises

PHYSICAL ASPECT OF THE ISLE OF PINES AND CLIMATE.

The Isle of Pines lies about 60 miles south of Cuba, and

Can be reached by rail from Havana to Batabano and thence by

sailing vessel or steamer to the island.

The Isle of Pines is about 30 by 40 miles in extent, contain-

ing some 1240 square miles, or a trifle less than the State of

Rhode Island. It is divided into two parts, the northern one

182 THE AMERICAN NATURALIST. . (VoL. XXXIX.

being the larger, by a fresh-water swamp, the ** Cienaga," that

runs across the island from east to west.

The land south of the Cienaga is of coral formation with a

very shallow soil spread over the coral rock, and with deep holes

or pits everywhere. A number of prints of fossil shells of

various kinds were observed in the coral rock. Fires devastate

this part of the island, burning up the soil and the very roots of

the trees and leaving nothing behind but the bare coral rock,

and the region is very sparsely inhabited. The trees of this

region are mostly hard wood, there being no pine and very few

royal palms.

North of the Cienaga, the country is of a very different char-

Fic. 3.— Casas River, Caballos fuis qund in e distance. Mangrove bushes in the fore-

ground along the river, and a palmetto scrub

acter. There are here a number of mountains rising abruptly

from the plain, Pico de la Dacuilla, the highest, having an

altitude of about 2000 feet. The flat country is diversified by

pastures, cultivated fields, open pine woods, and groves of royal

palms and palmettos and along the water courses there are dense

tropical forests. ' The mountain sides are very rocky and are

clothed chiefly with scrub and thorn bushes and, where there is

soil enough, some good-sized trees. The banks of the rivers and

No. 460.] BIRDS OF THE ISLE OF PINES. 183

many parts of the shore of the island are fringed with man-

groves which give way as the land rises, to a dense growth of

palmetto.

In the Isle of Pines the rainy season begins in the early part

of May, and rain falls continually until October. The character

of the country is entirely changed. The Cienaga is covered by

two or three feet of water and the rivers, which are nearly dy

in the dry season, become torrents.

Great difficulty was experienced in taking photographs

especially after the rain began, but the accompanying views

selected from a great many, give some idea of the general

character of the island.

BIRDS.

About eighty-three species of birds, most of them resident,

breed in the Isle of Pines. Besides these, a few northern

species either winter there or make a short stop in spring or

autumn, but the list of migrants thus far is not a long one.

Owing to its nearness to Cuba and to the fact that, geo-

logically speaking, its separation from that island was recent,

one would not look for any marked peculiarities in the birds of

the Isle of Pines, and such do not exist. Nevertheless many of

the birds of the island have already become slightly changed

and although they strictly represent the Cuban species, it seems

best to give some of them distinctive names. The changes that

have thus far taken place are chiefly in size and proportions,

colors in most of the species remaining the same or very similar.

There is no rule in these changes in size,— some of the birds of

the Isle of Pines are larger, others are smaller than their Cuban

representatives.

All the birds of the island are well known by the natives, who

have a name for nearly every species. In the following list we

give these names. In some cases we may be slightly in error

in the spelling of them as it is impossible to find a native who

can write them correctly.

1 This number includes some species probably now extinct and a few u.

birds—such as the Frigate Bird and Flamingo — that may or may not Muay

breed in the island.

184 THE AMERICAN NATURALIST. | [Vor. XXXIX.

Some species that were seen and not taken by either Zappey

or Palmer and Riley, but were probably correctly identified, we

give with a question mark. It would be a pity to leave these

out of a list of the birds of the island and yet there must ever

be a doubt about such records, and this seems to usthe best way

to treat such cases. A few species, also included in the follow--

ing list, rest solely on Poey's authority (based on a list furnished

him by Gundlach).

Following is a list of the birds! of the Isle of Pines, with

FıG. 4.— Country back of the town of Nueva Gerona. Casas Mountains in the distance.

notes on their habits, distribution, etc., and with critical remarks,

and descriptions of a few new forms, drawn from the various

sources enumerated above.

1. Podilymbus podiceps (Linn.).— An adult female and

three downy young were found by Palmer and Riley in a small

lake near Nueva Gerona. One of the young was taken but the

old bird was very wary and could not be secured.

l The systematic sequence of this list is about the same as that followed by

Ridgway in the Birds of North and Middle America, now appearing in parts,

based principally upon Hans Gadow's A Classification of Vertebrata, pu and

Extinct, 1898, only turned about so as to bring the “lower” (less specialized)

orders first. Colors are according to Ridgway's Momenclature, and measurements

are in millimeters.

No. 460.] BIRDS OF THE ISLE OF PINES. 185

Two were shot by Zappey, and one of them saved, in March,

1902, at Laguna Grande, but in the spring of 1904 no Pied- :

billed Grebes were observed anywhere in the island.

2. Phalacrocorax dilophus floridanus (Aud.). “ CORNA ”

— Cormorants were common along the seacoasts of the island

and among the outlying cays, and undoubtedly all birds inhab-

iting the salt water belong to this form, which has been recorded

from Isle of Pines by Cory and by Gundlach. Specimens of the

Florida Cormorant were secured by Palmer and Riley on the

Cuban coasts, and many were observed at Batabano opposite the

Isle of Pines.

3. Phalacrocorax vigua mexicana (Brandt). ‘“‘ CORNA.”

— One young adult female, was taken in the Cienaga at Pasa-

dita in May. This was the only one observed.

This specimen is rather larger than usual for mexicana, but

E. W. Nelson who has compared it for us with the large series

collected by himself in Mexico, says that it is equalled and even

exceeded by some Mexican individuals, and authors generally

have considered the Cuban Fresh-water Cormorant to belong to

this race rather than true vigua.

The skin, no. 13,236, measures : wing, 268 ; tail, 164 ; tarsus,

50 ; exposed culmen, 50.

4. Anhinga anhinga (Linn). “Corsa REÁL.” — The

Anhinga was found by Zappey in the Cienaga only, where it

was fairly common and a number might be seen any day sitting

on dead branches of trees in different parts of the swamp, with

"wings and tail extended to the rays of the sun. One was seen

by Palmer and Riley at Nueva Gerona.

Two specimens — a fine pair of adults — taken by Zappey,

: May 28, 1904, do not differ in any way from Florida birds.

5. Fregata aquila Linn. “ RABIHORCADO.” — Occurs occa-

sionally off the south coast of the island, and during a severe

storm was seen high in air passing over the town of Santa Fe.

Palmer and Riley also saw it at Managua. ba

6. Pelecanus fuscus Linn. “Arcarraz.”— A few indi-

viduals were seen on the south, but none on the north coast. j

7. Pelecanus erythrorhynchos Gmel. — The White Peli-

can has been recorded by Cory from Isle of Pines. None were

186 THE AMERICAN NATURALIST. | (Vor. XXXIX.

observed by Palmer and Riley nor by Zappey on either trip. It

is probably a very irregular winter visitor to the island.

8. Ardea repens sp. nov.

Type from the Cienaga, Isle of Pines, adult 9, no. 13,241,

Coll. of E. A. and O. Bangs. Collected May 24, 1904, by W.

R. Zappey.

Characters. — Similar to Ardea occidentalis Aud. of south

Florida but very much smaller.

Color. — Entirely pure white; the bill yellow ; legs and feet

greenish yellow.

Measurements. —'Type: wing, 440; tail, 156; tarsus, 172;

exposed culmen, 144.

Since the ornis of Cuba has first been known, up to the pres-

ent time, references to Ardea occidentalis can be found in the

literature, but specimens do not appear to have been taken.

Birds from Cuba and the Isle of Pines are in all probability the

same, and certainly cannot be referred to A. occidentalis, being

far too small. This is all that can be said at present. Future

research may prove this bird to be the white phase of the Great

Blue Heron of Cuba, but here again there appear to be no

specimens, and it is not known to what form that bird belongs.

Under the circumstances we have thought it best to give the

white bird a name as it certainly is not A. occidentalis.

Zappey saw this bird but once — the one taken. Palmer and

Riley observed a few about the cays.

9. Ardea herodias Linn. (sub. sp. ?).— The Great Blue

Heron was seen on several occasions in the Cienaga, but was

very shy and none were secured. A few were also seen by

Palmer and Riley about the cays.

As stated under the preceding species, it is still unknown to

what form the Great Blue Heron of Cuba and the Isle of Pines

belongs, and possibly it may be the colored phase of the bird we

describe as Ardea repens.

10. Herodias egretta (Wilson). “ GARCILATE." — A few

Egrets were seen, in different parts of the island, both inland

and on the seacoast, always singly, and they were very shy.

No. 460.] BIRDS OF THE ISLE OF PINES. 187

In former years it was abundant, but has been nearly extirpated

for its plumes.

A fine adult female was taken at La Vega, May 22, 1904, and

one was obtained by Palmer and Riley at Nueva Gerona.

II. Florida czrulea cerulescens (Latham). ^ * GARGA

AZUL." — Very common, being found both on the seacoasts

and in the Cienaga.

Two specimens, 4 and 9, were taken respectively at Guana-

wana, May 15, and in the Cienaga, May 23.

I2. Leucophoyx candidissima (Gmel.). “GAarGA BLANCA.”

Fic. 5.— Palmetto and royal palms near the Casas Mountains.

— The Snowy Heron is now very rare in the Isle of Pines, hav-

ing been killed off for its plumes. One was seen in the Cienaga,

and at Jucaro a native had a wounded bird that was kept alive

in confinement, :

13. Hydranassa tricolor ruficollis (Gosse). “ GARGA. i

This species is not uncommon in the seacoast lagoons and the

brackish water of the rivers, but was only once seen in the

Cienaga.

188 THE AMERICAN NATURALIST. | (Vor. XXXIX.

One female was taken in the Cienaga, May 23, 1904.

14. Nyctanassa violacea (Linn.). *GuANABA."— Recorded

from Isle of Pines by Poey, Cory, and Gundlach. None were

seen by Zappey nor by Palmer and Riley.

J I5. Nycticorax nycticorax naevius (Bodd.).— In March,

1902, a flock of Black-crowned Night Herons was seen at a

fresh-water lagoon in the northern part of the island and two

others in a salt lagoon at Bibeyhagua. It is also recorded from

the island by Poey.

16. Butorides virescens maculata (Bodd.) “ AQUAITA."

— The Green Heron occurs, in small numbers, wherever there

is fresh water, and was also occasionally seen along the sea-

coast.

As has been pointed out by Riley, all West Indian Green

Herons are much alike, and must be called by Boddzrt’s name.

The form differs from true virescens of the mainland chiefly in

being smaller.

Two males were taken : one at Bibeyhagua, May 15, the other

at Santa Fé, April 20.

17. Butorides brunnescens (Lembeye).— Two specimens

of this dark-colored bird were taken by Palmer and Riley near

Nueva Gerona.

We cannot avoid a strong impression, despite its peculiar

coloration and the fact that young individuals are as different as

adults from 2. virescens maculata, that this supposed species is

a color phase of the ordinary bird. This, however, can be

proved by careful observation only, by ascertaining whether the

two breed together or mate each with its own kind only.

18. Ardetta exilis (Gmel.). — The Least Bittern was abun-

dant in the Cienaga in March, 1902. On the 1904 trip, made

later in the spring, none were found anywhere, leading to the

conclusion that those seen in March were winter residents and

that the bird does not breed in the Isle of Pines.

19. Botaurus lentiginosus (Montag.). — Recorded by Cory

and Gundlach from the Isle of Pines, but not observed by Zap-

pey nor by Palmer and Riley.

20. Eudocimus albus (Linn). “Coco.” — One of the

commonest and most characteristic birds of the Cienaga, flocks

No. 460.] BIRDS OF THE ISLE OF PINES. 189

of.from forty to fifty being often seen. It also occurs though

not in such large numbers in most parts of the island. It feeds

on snails, frogs, and lizards. The natives often tame the White

Ibis and it then runs about with the domestic fowl and eats

table scraps and the like, which it always carries to the nearest

water and soaks before swallowing. These tame birds were

also very fond of the bodies of small birds that had been

skinned, and would catch them when thrown to them, before

they touched the ground.

One specimen was taken, a male, at Pasadita, May 8.

21. Ajaia ajaia (Linn.). * CERvEIA." — The natives claim

that a few Roseate Spoonbills still occur in the Isle of Pines.

The species is recorded by Poey and formerly was not uncom-

mon. It was not seen by Zappey nor by Palmer and Riley.

22. Tantalus loculator Linn.— Recorded from the Isle of

Pines by Cory. Its occurrence there is probably only casual as

it was not found by Zappey nor by Palmer and Riley.

23. Phoenicopterus ruber Linn. '*FLAMENCO.'— A few

Flamingoes inhabit Punta del Este and Bibeyhagua. None

were seen alive, but one morning the tracks of about a dozen

were found in the mud, and on another occasion three individuals

that had just been shot by a native were examined.

24. Chen hyperborea nivalis (Forst.).— An occasional win-

ter visitor, recorded from the island by Cory and by Gundlach.

25. Dendrocygna arborea (Linn.). “ Lracwasa." — The

Whistling Duck occurs in considerable numbers in the Isle of

Pines. During the day it keeps concealed in the Cienaga but in

the evening, toward dusk, it leaves the swamp to feed in the

royal palms, alighting on the trees and picking off the berries.

One night a half a dozen or so alighted in the palms in the plaza

at Santa Fé, The call note of this bird is much like that of the

Wood Duck (Air sponsa).

Six specimens, adults of both sexes, were taken in the Cienaga

in May.

26. Querquedula discors (Linn.).—In March, 1902, the

Blue-winged Teal was in the Cienaga in considerable numbers.

On the second trip none were found, the species probably leav

ing for the north before the middle of April.

I9O THE AMERICAN NATURALIST. (VoL. XXXIX.

27. Cathartes aura aura (Linn.). “ Aura.’— The Turkey

Buzzard is very common everywhere in the island. The bird of

the Isle of Pines, and other West Indian Islands, is very much

smaller than that occurring in the southern United States and

FIG. 6. C" growth ehren the pine lands. The highest tree in the center of the

pict e that grows chiefly near the seacoast north of the Cienaga.

as Wied named the latter septentrionalis, Linné's name should be

restricted to the small southern form, since he gave the distribu-

tion of his Vu/tur aura as North America, Jamaica, Mexico, etc.

The Turkey Buzzard of the southern United States should be

known as Cathartes aura septentrionalis (Wied).

! Cathartes septentrionalis Wied, gourn. f. Orn., p. 119, 1856.

No. 460.] BIRDS OF THE ISLE OF PINES. I91

Two specimens, ? and 9, were taken at Santa Fé and meas-

ure as follows : —

No. Sex. Wing. Tail. Tarsus. Culmen.

13.376 9 483 236 69 38

13,377 4 456 228 69 41

28. Polyborus cheriway (Jacq.. “ Caraıra.”— This is

not a common bird in the Isle of Pines and is extremely shy.

Whenever there happens to be a dead animal anywhere, however,

one or two Caracaras will always be found near by. They also

feed on lizards and are said by the natives to kill small chickens.

One male was taken at Santa Fé, May 20. This specimen

does not differ from skins from Florida and elsewhere on the

continent.

29. Urubitinga anthracina (Licht.). “ BarisrA." — The

Cuban Crab-hawk is recorded from the Isle of Pines by Poey, as

Hypomorphus gundlachi Cab. :

There are no specimens available to us for comparison of the

Cuban bird, and we are therefore forced to follow the general

custom of placing it under true U. anthracina.

The species was not detected in the island by Zappey nor by

Palmer and Riley.

30. Rostrhamus sociabilis (Vieill). *'* CARBRETO.” — Com-

mon in the Cienaga and also seen at Santa Rosalia lagoon. Its

food consists of small snails, though the natives assert that it

eats frogs and lizards also.

One male taken at the Cienaga, May 23, is in every way like

specimens from Florida.

31. Falco peregrinus anatum (Bonap.).

One was examined in March, 1902, that had struck and killed a

hen, and being either unable or unwilling to let go, was chopped

to pieces by some natives with their machetes.

32. Falco columbarius columbarius Linn. — Recorded

from the Isle of Pines by Cory and by Gundlach as an occa-

sional winter visitor.

33. Cerchneis sparveria dominicensis (Gmel). “ CERNI-

CALO.” — Very common everywhere in the island. This form

has the same habit as the Sparrow Hawk of Florida, of congre-

* HALCÓN.” —

192 THE AMERICAN NATURALIST. [Vor. XXXIX.

gating in numbers wherever the brush or grass has been set on

fire and hovering just in front of the flames. In the Isle of

Pines they appear to get small lizards only in this way, there

being no small mammals.

Seven specimens were taken at Santa Fé, San Juan, Jucaro,

Laguna Grande, and Almacigos, in April and May. Of the

great number seen, one only was in the dark phase of plumage,

and Palmer and Riley state that a// observed by them were in

the white-bellied plumage.

34. Pandion haliaetus carolinensis (Gmel.).— Recorded

from the Isle of Pines by Cory; not observed by Zappey nor by

Palmer and Riley.

35. Colinus cubanensis (Gould). **CopoRuiz." — The

Cuban Quail was common in the pastures and fields about Santa

Fé and Nueva Gerona, where they were nesting in May.

Three males were taken at Santa Fé and Callebonita in May ;

these specimens do not differ in any way from Cuban examples.!

36. ?Rallus elegans Aud. “ GALLINUELA.” — In March,

1902, a large rail was rather common in the Cienaga, and

several specimens were taken. None could be found on the

later trip and the bird apparently does not breed in the island.

(The skins taken on the first trip are in the Tring Museum, but

Zappey is sure they were referable to the King Rail.)

.37. Gallinula galeata Bonap. **GarriNETA." — In March,

1902, a few individuals were found in Santa Rosalia lagoon.

None were met with on the later trip and it is probable that the

gallinule does not breed in the island. Recorded from the Isle

of Pines by Cory.

38. Ionornis martinica (Linn). “GALLINUELA.” — The

Purple Gallinule breeds abundantly in the Cienaga but was not

noted anywhere else in the island.

Four males were taken in the Cienaga at Pasadita, in May

and June. These specimens are slightly larger than examples

from the mainland of the southern United States, measuring as

follows : — :

‘The Guinea Fowl (JVu»izda meleagris Linn.), and the Domestic Hen (Gallus

sp. ?), have both run wild in the Isle of Pines, and are occasionally found through-

out the island, apparently perfectly naturalized.

No. 460.] BIRDS OF THE ISLE OF PINES. . 193

No. Sex. Wing. Tail. Tarsus. Bill.1

13,232 d ad. 182 70 59 31

13,233 d ad. 183 79-5 63.5 3o

13,234 d ad. 190 75 59 30.5

13,235 d ad. 179 69 61.5 31

39. Fulica americana Gmel.— Recorded from Isle of Pines

by Cory and by Gundlach. Not noted by Zappey nor by Pal-

mer and Riley. As with many other species that are winter

residents in the Isle of Pines, the trips made by Zappey and

by Palmer and Riley were too late in the season to find these

birds still in the island.

40. Grus nesiotes sp. nov?

"GRUELA.-

Type from La Vega, Isle of Pines, adult d', no. 13,238, Coll.

"of E. A. and O. Pangi Collected May 8, 1904, by W. R.

Zappey.

Characters.— Similar to the Sandhill Crane of Florida,

(usually called Grus mexicana Müll.) in color, but slightly

darker and not so clear a gray on back ; smaller with shorter

tarsus; beak somewhat stouter and heavier.

Measurements : 9 —

No. Sex. Locality. Wing. Tail. 'Tarsus. Culmen.

13,238 d ad. Isle of Pines, La Vega 474 187 209 125

13,239 d ad. Isle of Pines, Pasadita ^ 460 171 204 133

1 Measured from a point in line with eye and nostril to tip.

* This bird may or may not be considered different urina from the Sandhill

Crane of North America to rank as a full species; we e given it a binomial

because we "9 agree with Dr. Sharpe that the bird d Ardea (Grus) mext-

cana by P. L. S. Müller is not the one to which the name is generally appli

—the in Crane of North America. Until the synonymy of these birds is

properly adjusted it is better not to give the Isle of Pines Crane as a subspecies.

? For en with these, specimens from the United States measure as

No. Sex. Locality. Wing. Tail. Tarsus. Culmen.

684 d ad. Wisconsin 508 202 230 135

691 d young. N. Dak., Harrisburg 518 187 224 124

10717 d ad. TN. Meo 514 192 238 125

10718 d ad. 494 195 248 132

4107 d ad. Fis. Henderson Cip 470 170 223 128

444

10,716 9 ad. Sr Haines City 465 188 247 136

194 THE AMERICAN NATURALIST.. [Vor. XXXIX.

The Sandhill Crane is rare and of local distribution in the

Isle of Pines, and was only met with in the high, open country

just north of the Cienaga, where it usually occurred in pairs,

though on one occasion a flock of six was seen. When dis-

turbed, it utters a loud honking or gobbling call note not unlike

some of the sounds produced by the Domestic Turkey. The

birds seen were always exceedingly shy, and the two specimens

were secured with a good deal of difficulty.

On May 20, a small downy young individual was found run-

ning about alone. It was exactly the color of the soil. It was

kept alive for a day or two but would not eat anything given

it. The skin is that of a young not long hatched. It is covered

with down which is tawny along the back, tawny-ochraceous on

sides, and whitish on throat and middle of belly.

After careful comparison of a large series of North American

Sandhill Cranes, we feel fairly sure that the birds still breeding

in Florida are not different from those that breed in North

Dakota and other parts of the west. Probably in former years

the breeding range was continuous or nearly so, and it is due to

the interference of man that the Florida bird is now isolated.

In the breeding season the Sandhill Crane is much browner,

— losing most of the pearly gray of the back and neck, — than

in fresh autumn plumage, and this is true of birds both from the

west and from Florida. Unfortunately, however, we have seen

only breeding birds and birds killed in early spring from Florida,

and therefore no gray ones, but we have no doubt that fresh

autumnal specimens from Florida would be quite as gray as those

from the west. In measurements there is no difference.

The bird of the Isle of Pines, and almost certainly Cuba also,

differs from that of the continent in its decidedly shorter tarsus,

heavier bill, and slightly smaller size. In color the difference is

slight, but still our two Isle of Pines skins are rather darker and

browner than any breeding Florida birds with which we have

been able to compare them.

41. Aramus giganteus holostictus (Cab.)! * GuARACAO."

! Notherodius holostictus Cabanis, Journ. J. Orn., p. 426, 1856, based on Cuban

specimens.

No. 460.] BIRDS OF THE ISLE OF PINES. 195

— The Limpkin was found in the Cienaga only, where it was fag

from common, and where one adult male was taken in May.

This specimen is smaller, with shorter tarsus, and much

shorter and smaller bill, than any in a large series of Florida

birds with which we have compared it. It is also paler in

general coloration; the tail is lustrous olive brown (dark,

lustrous purple in true A. giganteus) and the white markings on

wings, wing-coverts and scapulars are smaller. The skin, no.

13,237, d ad. measures: wing, 308; tail, 138; tarsus, 114 ;

exposed culmen, 110.

We have therefore thought it best to recognize the Cuban and

Isle of Pines birds as a subspecies.

42. ?Ochthodromus wilsonius rufinucha (Ridg.). “ FRA-

ILECILLO." — A few birds, undoubtedly belonging to this form,

were seen along the shore at Plaza Larga, but none were

secured. _

43. Oxyechus vociferus torquatus (Linn)! “ FRAIL-

ECILLO.” — A few pairs of Killdeer breed in the Isle of Pines.

They were seen on several occasions, and a young in the down

was caught, but let go again at the beach at Bibeyhagua.

One adult male was taken April 21, at Laguna Grande, and

Palmer and Riley took specimens at Nueva Gerona.

The breeding Killdeer of the Greater Antilles is a good deal

smaller than the bird of continental North America and should

be recognized as a subspecies.

Our specimen, d' ad., no. 13,335, measures: wing, 146; tail,

82.5; tarsus, 34; exposed culmen, 21. :

The larger Killdeer of the north winters in many of the

islands, and this fact must be borne in mind in identifying speci-

mens, else confusion is sure to ensue. There is no trouble in

distinguishing the two forms, however, when breeding birds are

compared. : :

44. Himantopus mexicanus (Müll). “Zararıco REAL” —

Two Black-necked Stilts, one of which, an adult fémale, was

taken, were found in the Salina at Bibeyhagua, May 15. The

1 Charadrius torquatus Linn., Syst. Nat., vol. 1, p. 255, 1766, based on Pluvialis

dominicensis torquata Briss., Aves, vol. 5, p. 70, pl. VI, fig. 2, from Santo Domingo.

196 THE AMERICAN NATURALIST. (VoL. XXXIX.

species is probably of very casual occurrence anywhere in the

West Indies.

45. Catoptrophorus! semipalmata semipalmata (Gmel.).

*ZaRAPICO REÁL."— No Willets were met with by Zappey

nor by Palmer and Riley. It is recorded from the Isle of Pines

by Poey.

46. Totanus melanoleucus (Gmel). “ Zararıco REÁL."—

One specimen, an adult female, was taken at the Salina at

Bibeyhagua, May 15.

47. Totanus flavipes (Gmel.).— In March, 1902, specimens

of the Summer Yellowlegs were taken, but none were observed

on the last trip to the island.

48. Helodromas solitarius solitarius (Wils.). ‘ ZARA-

PICO."— One adult female was taken May 11, at Jucaro ; it was

in a little puddle at the roadside left by a heavy shower.

49. Actitis macularia (Linn.). — Spotted Sandpipers were

not uncommon about the shores of the island in March, 1902.

None were seen on the last trip.

50. Asarcia spinosa (Linn). * GarriTo."— The Jacana

occurs in every fresh-water lagoon, but is most abundant in

Santa Rosalia lagoon and the Cienaga.

When disturbed it stretches up its wings and runs along over

the lily-pads and weeds for a short distance before taking flight,

at the same time uttering a loud alarm note that sets all others

in the vicinity to flying.

Three specimens were taken at Laguna Grande and Pasadita,

in April and May.

51. Sterna maxima Bodd. “Gaviora.”— The Royal Tern

was common along the seacoasts of the island and on the man-

grove cays. Several were shot, but fell into the ocean and

before they could be retrieved, were gobbled up by sharks.

52. Columba inornata Vig. “Paronea Baso,” “ TorR-

CAZA."— One specimen of this pigeon was taken in March,

1902. It was not met with at all on the second trip and is said

by the natives to be very rare in the Isle of Pines. It is among

the species given from the island by Poey.

1 Cf. Richmond, Proc. Biol. Soc. Washington, vol. 18, p. 75, Feb. 21, 1905.

No. 460.) BIRDS OF THE ISLE OF PINES. 197

53. Columba leucocephala Linn. “ (ToRCAZA CABEZA-

BLANCA."— The White-crowned Pigeon is not uncommon along

the river courses, especially where there are royal palms, upon

the fruit of which it feeds.

Two specimens, both males, were taken at La Vega in April.

54. Columba squamosa Bonn.— Palmer and Riley inform

us that this species occurs in the vicinity of Nueva Gerona but

is rare there.

55. Zenaidura macroura bella Palmer and Riley. “.Par-

OMA,"— Throughout the island in the open pine woods, palmetto

groves, and especially in old fields grown up to weeds, the Cuban

Mourning Dove is an abundant bird. Several nests were found

in low trees five or six feet from the ground.

Three specimens, two males and a female, were taken at Rio

Santiago and Hospital in May. These are similar in every way

to Cuban examples.

56. Zenaida zenaida zenaida (Bonap.). “ PALoMA."— The

Zenaida Dove inhabits the same sort of country as the last

species, the two being found together, but it is not so abun-

dant.

Two specimens, both males, were taken at Almacigos, April

I9.

57. Columbigallina passerina aflavida Palmer and Riley.

* TojosrrA."— Common everywhere in the island except in the

denser woods. Several nests were found placed on the ground,

containing two eggs each.

Seven specimens, of both sexes, were secured at Callebonita,

Hospital, Jucaro, and San Juan, in May. These do not differat

all from Cuban specimens.

58. Geotrygon montana (Linn.). * BovERo."— The Ruddy

Quail-dove occurs in the Isle of Pines in the denser woods only,

usually in rather moist places, where the ground is often flooded

after heavy rains. It is nowhere abundant. When flushed

from the ground it flies but a short distance and on alighting

again runs along for a few feet and conceals itself among the

vegetation much after the manner of the American Woodcock

(Philohela minor), which it curiously resembles when started in

the deep woods.

198 THE AMERICAN NATURALIST. [Vor. XXXIX.

Six specimens, including both sexes, were taken at La Vega

Pasadita, and Callebonita in May and June.

These skins are not to be distinguished in any way from skins

from Jamaica, the type locality of the species.

59. Geotrygon chrysia (Bonap.). “Canıko.’— The Key

Fıc.7 ee River before w rainy season when the water was very low. ‘‘ Guana

blan ' palms in the foregrou

West Quail-dove is very rare in the Isle of Pines occurring only

on one or two of the mountains and in the dense forest south of

the Cienaga.

Only two individuals were seen. These were both secured, at

Pasadita, one in May the other in June.

No. 460] BIRDS OF THE ISLE OF PINES. 199

60. Starnoenas cyanocephala (Linn). “ Pernız.”’—This

bird has not been actually seen by any naturalist in the Isle

of Pines. We include it because the natives who know it

well positively assert that a few inhabit the Caballos Moun-

tains and some point near the south coast.

61. Saurothera merlini decolor subsp. nov.

* ARRIERO."

Type from La Vega, Isle of Pines, adult 4, no. 13,246, Coll.

of E. A. and O. Bangs. Collected April 24, 1904, by W. R.

Zappey.

Characters. — Somewhat similar to true S. merlini d'Orb. of

Cuba, but smaller, with decidedly shorter bill; much paler in

color, wholly lacking the hazel or pale chestnut suffusion of

back, head, and rump, these parts being, in the new form, uni-

form dull hair-brown ; the ferruginous color of the lower under-

parts also much paler and duller and more restricted, never

reaching the lower breast. In general coloration the Isle of

Pines bird — except for the chestnut patch in the wing — more

nearly resembles S. dahamensis than S. merlini merlini.

The young is like the adult except that it lacks the black sub-

terminal band to the rectrices.

Iris brown, bare skin around eye scarlet, legs slate blue (from

fresh specimen just killed).

Measurements : —

No. Sex. Wing. Tail. Tarsus. Culmen.

13,246 d ad. "mr , 267 42.5 52.5

13,247 d ad. 161 262 43 55

13,243 d ad. 164 235 43 52

13,242 d ad. 158 255 41.5 51.5

13,244 9 ad. 149 226 39-5 50

13,245 Q ad. I 252 40.5 54

The Lizard Cuckoo of the Isle of Pines is a common bird in

rough, rocky country wherever there is a thick growth of scrub

and bushes, and is very tame. It has a habit of hopping from -

one branch to another till it reaches the top of a bush and then

sailing down to the ground or the lower branches of another

200 THE AMERICAN NATURALIST. . (Vor. XXXIX.

bush. Its usual call note is a sort of laugh that begins low and

slowly, and rapidly ascending, ends in a loud chuckle. When

two individuals are within sight of each other they often go

through a curious performance, which consists in lowering the

head and dropping the feathers of the throat which then looks

like a large pouch, at the same time spreading the wings and

tail to their fullest extent and repeating the loud chuckling notes

that end the usual call. The stomachs of those taken con-

tained the remains of small lizards, beetles, caterpillars, and

large moths.

Seven specimens were taken, adults of both sexes and one

young, at La Vega, Callebonita, and Hospital, in April, May,

and June.

The Isle of Pines Saurothera is a very well marked form dif-

fering much from true S. merlini of Cuba in size and propor-

tions as well as in its paler and plainer coloration, and perhaps

should be considered a distinct species. We, however, prefer to

treat representative island forms as subspecies, unless they pre-

sent even more strongly marked characters than do these two

cuckoos. By so doing, the affinities of a bird are seen at a

glance by its name, whereas, by the use of binomials they are

lost.

62. Crotophaga ani Linn. *Jupio." — The Ani is a com-

mon bird in the Isle of Pines, occurring in all pastures, in

brushy regions, and along the river courses. It was often seen

on the backs of horses, cattle, and hogs picking off ticks.

Five specimens were taken at Callebonita, Santa Fé, and

Jucaro, in April and May.

63. Ara tricolor (Bechst.). * GuAEAMÁYvO." — It has been

supposed that perhaps the Cuban Macaw still lingered in the

Isle of Pines. Unfortunately this is not so. The last pair

known in the island was shot at La Vega, near the Cienaga,

about the year 1864, and none have been seen since. This in-

formation was furnished by the man on whose plantation they

were shot.

64. Conurus euops (Wagler). “ PERIQUITO." — Formerly

abundant in the Isle of Pines, the paraquet has been nearly if

not quite exterminated in very recent years. Nothing was seen

of it and the natives all said that none now occur in the island.

No. 460.] BIRDS OF THE ISLE OF PINES. 201

65. Amazona leucocephala (Linn.). ‘ Cororra.’’— The

parrot is still common in the central part of the island, but is

rare south of the Cienaga — a few pairs only being seen in some

royal palms at Pasadita.

In May, the parrots were breeding. The nests usually con-

tained young though several were examined in which there were

eggs, four in number, of a whitish color. The nesting site is

invariably an old woodpecker's hole in the trunk of a species of

palm that has a large swelling about midway up. The parrot

feeds largely in the pines, eating the ends of the new shoots

that are soft and green.

Hundreds of young birds are taken annually by the natives

and sent alive to the United States. The exporting of live par-

rots being the chief industry of the island, nearly every nest on

the island is found and robbed every year, and although the

natives do not kill the old birds and dislike very much to have

them shot, nevertheless the parrot is steadily decreasing in num-

bers year by year, and must inevitably go the way of the macaw

and the paraquet unless some steps are taken to protect it.

One adult male was taken at Hospital, May 12. This does

not appear to differ in any way from Cuban examples.

66. Todus multicolor Gould. ‘ PODoRERA.” — Along the

river courses and dry gulches, where there is a thick growth of

brush, the little Tody is frequently met with sitting upright on -

a branch from which it occasionally darts to catch some insect on

the wing, its wings as it does so making a loud whirring sound.

Its call note is a curious sound much like that produced by

hitting two small stones together.

Eleven specimens, adults of both sexes, were taken at Santa

Fé and Callebonita in April and May, and are quite the same as

Cuban examples.

67. Ceryle alcyon (Linn.. *MaARTIN ZAMBULLIDOR." —

The Belted Kingfisher is a regular winter visitor to the Isle of

Pines. In March, 1902, it was not uncommon, but on the last

trip none were seen, all having probably left for the north.

68. Nyctalops stygius siguapa (d'Orb.)! “ SIGUAPA." —

1 Otus siguapa d'Orb., in Ramon de la Sagra's Histoire de l'Isle de Cuba,

Oiseaux, p. 40, pl. 2, 1839. Based on Cuban specimens.

202 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

The Cuban Eared Owl inhabits in the Isle of Pines the heavi-

. est and densest forests only. It is very rare, and being wholly

nocturnal is extremely hard to obtain.

One fine adult male was taken at La Vega, May 25. This

specimen compared with three continental examples,— one each

from Brazil, Mexico, and Guatemala — differs in being less

buffy both above and below, the under parts are much whiter,

and the facial disk is white. It is probable that the Cuban bird

is the same, and the island race named by d’Orbigny seems a

perfectly valid one.

69. Gymnasio lawrencei (Scl. and Salv.). * COTUNTO.”

— This queer, long-legged little owl, with much the general

appearance of a Burrowing Owl is strictly nocturnal, spending

the day in hollow trees. A pair taken at Santa Seville, May

31, had with them a brood of three half-grown young in a hole

in a tree. These young birds were kept alive for a time and

were then given to a native, who like so many of his country-

men was very fond of taming and keeping birds in confinement.

Three specimens, two adult males and an adult female, were

taken at Pasadita and Santa Seville, in May. These skins com-

pared with a series of six from Cuba show a slight difference in

color, being paler with less of a brownish or rufous cast than

the Cuban specimens. In measurements they do not differ,

and the slight color difference may or may not hold in larger

series from the two islands.

70. Glaucidium siju (d’Orb.). “ Sıyu.”— One of the charac-

teristic bird-sounds of the island, with which one soon becomes

very familiar, is the cry of this little owl. Though the bird is

diurnal, its call is often heard at night as well as by day. It is

generally distributed throughout the island and is very common.

The stomachs of those taken contained nothing but insects,

beetles of various kinds forming the greater part of the con-

tents.

Six specimens, adults of both sexes, were taken at Santa Fé

and Callebonita in April, May, and June. These are indistin-

guishable from Cuban specimens.

71. Strix pratincola furcata (Temm.). “ LECHUZA.” —

The Barn Owl is not at all common in the Isle of Pines. But

two were seen and two others heard at night.

No. 460.] BIRDS OF THE ISLE OF PINES. 203

One adult female was taken at Santa Seville. It had been

eating a Ruddy Quail-dove (Geotrygon montana).

72. Chordeiles virginianus virginianus (Gmel.). — Prob-

ably an irregular migrant, though it is recorded from Cuba by

Cory.

On May ro, a male was flushed from the ground and alighted

in a pine, at Santa Fé, where it was shot. This specimen

measures: wing, 200; tail, 105 ; tarsus, 14; culmen, 8. Itis

in every way like birds that breed in New England.

73. Chordeiles virginianus minor (Cab.) “ CERICADAY.”’

— Common everywhere in the island in the more open country

and among the. pines. In rainy weather it was often seen

flying during the day, and at other times roosting lengthwise

on a pine limb.

Five specimens were taken at Almacigos, Santa Fé, and Hos-

pital, in April and May.

Chordeiles virginianus minor like many other species of birds

of somewhat similar general coloration, appears to be dichromatic,

having a rusty and a gray phase of plumage, regardless of sex,

age, or season. In the present series all are in the rusty phase

of plumage except one female that is very gray. In a series

from Cuba we find both phases — one male from Holquin, May

31, being quite the color of Florida specimens of C. virginianus

chapmani. That it is not that form can of course be told by its

smaller dimensions. :

74. ? Antrostomus vociferus (Wilson).— Recorded from the

Isle of Pines with a query by Poey. We consider this an

extremely doubtful record probably applying to the next

species.

75. Antrostomus cubanensis Lawr. * GuARAIBA." — A bird

of this species was started from the ground in the dense woods

south of the Cienaga in June, and was shot, but was so mangled

that it could not be saved, It was the only one seen.

76.? Hemiprocna zonaris pallidifrons (Hartert).— Palmer

and Riley saw about the crest of the mountain at Nueva ‘Gerona

some large swifts, that they felt confident belonged to this form.

77. Riccordia ricordii(Gerv.). “ Zung ZUNG."— The hum-

mingbird is rather generally distributed throughout the island,

204 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

though nowhere abundant. Several nests were found contain-

ing two eggs each. It is a noisy little bird and its mouse-like,

squeaking note is uttered at frequent intervals, especially when

anything attracts its attention.

Four specimens, adults of both sexes, were taken at Almacigos

and Santa Fé, in April, May, and June.

78. Prionotelus temnurus vescus subsp. nov.

* TocoRoRo."

Type from Almacigos, Isle of Pines, adult 4, no. 13,250, Coll.

of E. A. and O. Bangs. Collected April 19, 1904, by W. R.

Zappey.

Characters. — Similar to true P. temnurus (Temm.), of Cuba

in color-pattern and probably in color also. (The Isle of Pines

series was taken in spring and early summer, and all Cuban

specimens with which we have been able to compare them, in

winter, except one. The red belly-patch in the Isle of Pines

specimens is much paler and more pinkish — less geranium red —

than in the Cuban skins, but the one summer specimen from

Cuba is like them in this respect and this difference in the color

of the belly-patch is probably due to fading). Much smaller

with much shorter tail; in the new form the wing averages

114.11, the tail 107.55 ; in true P. temnurus the wing averages,

123.41, the tail 119.41.

Iris bright carmine, lower mandible iib (from fresh speci-

men before skinning).

Measurements : —

No. Sex. Wing. Tail. Tarsus. Culmen.

13,250 d ad. 113.5 104 18 19.5

13,251 d ad. 115 104 18 19

13,254 d ad. 114 106 17.5 19.5

13,255 d ad. 113 110 18.5 18.5

13,258 d ad. 114 108 18.5 18.5

13,252 9 ad. * 115 107 18 19

13,253 9 ad. 113 108 17.5 18.5

13.256 Q ad. 115.5 113 17.5 18

13,257 9 ad. 114 108 17 18.5

1 In every instance the tail is measured to the end of the longest shaft, not the

end of the projecting webs.

No. 460.) BIRDS OF THE ISLE OF PINES. 205

For comparison with these a series from Cuba measures as

follows : —

No. Sex. Locality. Wing. Tail. Tarsus. Culmen.

14,927; d ad. Cuba, Halquin 124 118 19 19

PS gJubS H 12 118 18.5 17.5

14,0025 "d ad. che xx (123.8 ^ 130.5 18 18.5

14,920 /9 adi; S e 12 117 18 18

11,976 d ad. Cuba, El Guama 124 120 18 20

11,975 9 ad. Cuba, San Diego de los Baños 125 12:

The Trogon is rather common in the dense woods and along

(The birds held up

Fic 8.— Cienaga, at Pasadita, a short time after the rains had begun.

are Sandhill Crane and the White Ibis.)

the river courses. It is a stupid sluggish bird and very tame.

Its food consists of fruits of various kinds.

Nine specimens, adults of both sexes, were taken at Puebla

Nuevo, Almacigos, Pasadita, and Callebonita, in April and May.

These are so very much smaller than Cuban examples that we

have thought it best to separate the Isle of Pines bird as a sub-

206 THE AMERICAN NATURALIST. | (Vor. XXXIX.

species, though its smaller size seems to be the only character

by which it can be distinguished.

79. Melanerpes superciliaris (Temm.). **CARPINTERO."

— An extremely abundant and very noisy bird, found over

nearly all the island.

Eight specimens, adults of both sexes and two young, were

taken at San Juan, Jucaro, Nueva Gerona, and Almacigos, in

April, May, and June. These skins run slightly smaller than

Cuban ones and have less of the olivaceous tinge below and

slightly less red on the belly. All of these characters, however,

are rather inconstant and the form though slightly different is

not enough so to be regarded as a subspecies.

The young — a male and a female taken June 4 — differ from

the adults in having the feathers of the breast, belly, and back

tipped with dull scarlet ; the scarlet of head duller, more orange ;

the female has scarlet tips to the feathers of the middle of the

crown and differs from the male, only in having the frontal band

wider and dull gray instead of white.

The skins measure as follows : —

No. Sex. Wing. Tail. Tarsus. Culmen.

13,262 d ad. 134 go 27.5 37-5

13,261 d ad. 140 92 2 40

13,259 ĝ ad. 134 91 26 38.5

13,260 d ad. 134.5 91.5 26.5 36.5

13,263 9 ad. 133 9 2 36

13,264 9 ad. 130 85 much worn 26 35-5

80. Sphyrapicus varius varius (Linn.)— A migrant or

winter visitor in the Isle of Pines, first recorded by Poey. In

March, 1902, several individuals were seen, but none were noted

on the last trip, as it was too late in the season.

81. Xiphidiopicus percussus (Temm.) “CARPINTERO

REÁL.” — The Green Woodpecker is common in the Isle of

Pines and generally distributed, and its low grating croak soon

becomes a familiar sound.

Eight specimens, adults of both sexes, were taken at Santa

Fé, Callebonita, and Jucaro, in April and May. These are not

to be distinguished from Cuban specimens.

82. Pitangus caudifasciatus (d'Orb). “ PITIRRE.” — A

No. 460.] BIRDS OF THE ISLE OF PINES. 207

not uncommon species along the river courses but always found

near water. One nest was found in a palmetto close to the

trunk about eight feet from the ground.

Nine specimens were taken at Santa Fé, Hospital, Jucaro,

and Callebonita River, in April, May, and June.

83. Blacicus caribzus (d’Orb.). “ Bonrro." — This little

flycatcher was found in low trees and among the thinner brush,

always near the ground.

Six specimens, adults of both sexes, were taken at San Juan

and Santa Fé, in April and May.

84. Myiarchus sagre (Gundl). *'Bonrro."— Common in

the pine woods, but not observed elsewhere in the island.

Seven specimens were taken at Santa Fé, Callebonita, and

Jucaro, in April, May, and June.

85. Tyrannus dominicensis dominicensis (Gmel). “ Pır-

IRRE.” — The Gray Kingbird is abundant in the pine woods and

scattered palmettos, but avoids the denser forest.

Seven specimens were taken at Santa Fé, Hospital, Callebon-

ita, and Jucaro, in May.

86. Tyrannus cubensis Richmond. ‘ PITIRRE DE AGUA."

—The huge Cuban Kingbird is rare in the Isle of Pines. Only

six were seen, of which five were shot. They were always near

water. The natives say that this tyrant-bird catches small fish

in the streams after the manner of a kingfisher ; the stomachs

of those taken, however, contained only remains of insects and a

few berries.

Five specimens were taken at Santa Fé, La Vega, Almacigos,

and Mal Pais, in May.

None of the Isle of Pines tyrant-birds differ in any way from

those of Cuba.

87. Galeoscoptes carolinensis (Linn.). “ ZORZAL Gato.” —

A regular migrant or winter resident, often seen during March,

1902, and once observed in April, 1904. Recorded from the

island by Poey, Cory, and Gundlach.

88. Mimus orpheus (Linn.).— Given as occurring in the

Isle of Pines by Cory, the mockingbird is said by the natives to

inhabit the south coast in small numbers. None were seen on

either trip.

208 THE AMERICAN NATURALIST. (VoL. XXXIX.

89. Myadestes elizabeth retrusus subsp. nov.

* REISENOR."

Type and only specimen from Pasadita, Isle of Pines, adult

male, no. 13,435, Coll. of E. A. and O. Bangs. Collected May

25, 1904, by W. R. Zappey.

Characters.— Similar to true M. elizabeth (Lembeye) of Cuba

in size and proportions, but much paler in color; general color

above hair-brown (olive brown in true M. elizabeth); ear coverts

much paler, wholly lacking the tawny tinge of these parts in

true M. elizabeth; the ochraceous line running from eye to

‘frontal apex much paler and less conspicuous; eye-ring much

paler.

Measurements.— Type, adult male: wing, 88.5; tail, 82;

culmen, 12.

The Isle of Pines Solitaire is very rare and occurs in the

densest forests only, where, on account of its retiring habits and

dull coloration, it is very hard to shoot. Its loud, ringing song

can be heard a great distance, and is almost startling in the still

forests in which the bird lives. The stomach of the only speci-

men taken contained a few berries and the remains of insects.

The form can be told at a glance from Cuban specimens on

account of its very much paler coloration, and is a strongly

marked subspecies.

90. Mimocichla rubripes rubripes (Temm.). ** ZORZAL."

— A common species, found throughout the island. It keeps

rather more to the brush and the woods than does Merula

migratoria, which it otherwise much resembles in habits. It is

a very conspicuous bird as it runs along the ground or hops

about in the brush, with wings lowered and tail thrown upward.

Seven specimens, adults of both sexes, were taken at Santa

Fe, San Juan, Hospital, and Callebonita in April and May.

These seem wholly referable to true M. rubripes, differing only

in that the rufous tinge of the belly is slightly paler and less

extensive.

91. Polioptila carulea (Linn.).— The Blue-gray Gnatcatcher

was found in the island in March, 1902, though none were seen

No. 460.] BIRDS OF THE ISLE OF PINES. 209

on the last trip. It is also recorded from the Isle of Pines by

Poey.

92. Vireosylva calidris barbatula (Cab.). “ PREDICADOR."

— A rather common bird in the Isle of Pines, frequenting trees

of medium height. The iris is red-brown.

Ten specimens, adults of both sexes, were taken at Jucaro,

Callebonita, and Santa Fé, in April and May.

93. Vireo gundlachi Lembeye. “Juan Cnurivi."— Gund-

lach's Vireo is very rare in the Isle of Pines. One pair was

found in some brush and small trees at Callebonita, and secured

May 3. These were all that were seen. The natives knew the

bird, but said it was an uncommon species.

The two specimens secured differ somewhat from Cuban skins

and more material might or might not bear out these differ-

ences. If it did, the form from the Isle of Pines would be

worth recognizing as a subspecies. The male differs from

Cuban males in being paler on the cheeks with much more of a

buffy tinge there; the female is paler throughout than in Cuban

examples, and considerably lighter in color below. The iris in

this form is light brown.

. Corvus nasicus Temm. *Cao."— The Crow was

found sparingly, usually in pairs, near the Cienaga. It is a

restless bird and has a habit, when one comes within sight, of

hovering over one's head high in air screeching and scolding

continuously. The natives sometimes tame the Crow and teach

it to say a few words. The iris is dark red.

Five specimens, adults of both sexes, were taken at La Vega

and Pasadita in April and May.

95. Progne cryptoleuca Baird. * GoLoNpRINA."— Not com-

mon in the Isle of Pines. It was seen several times, but no

nesting place was found. Palmer and Riley found small colonies

in the pines at Managua.

96. Petrochelidon fulva fulva (Vieill.). “ GoOLONDRINA."—

Like the Martin, the Cliff Swallow was not found nesting in

any region visited by Zappey. It was seen flying several times.

Palmer and Riley found it abundant in the lowlands near Nueva

Gerona.

97. Mniotilta varia (Linn.).— Recorded from the island by

Poey, and seen on the March, 1902, trip.

210 THE AMERICAN NATURALIST. | [Vor. XXXIX.

98. Compsothlypis americana (Linn.).— Recorded from

the island by Poey, and also seen in March, 1902. Without

specimens it is of course impossible to tell to which subspecies,

as now recognized, this record applies.

99. Chrysocantor petechia gundlachi (Baird).— The Man-

grove Warbler was not observed in the Isle of Pines on either

trip, though it was common at the opposite coast of Cuba at

Batabano where a series of specimens was taken while waiting

for a vessel to sail for the island.

It is recorded from the island by Poey and by Cory.

100. Dendroica carulescens (Gmel.).— Recorded from Isle

of Pines by Poey and by Cory and not uncommon in March,

I902. None were seen in 1904.

101. Dendroica virens (Gmel.).— First recorded from the

island by Poey, and later Gundlach says that he took his first

specimen of this species in the Isle of Pines in January, 1855.

102. Dendroica dominica dominica (Linn.).— This is

another species recorded by Poey and found in March, 1902,

but not seen in 1904.

103. Dendroica discolor (Vieill).— Given by Poey from

Isle of Pines, but not observed on either of the trips made to

the island by Zappey.

104. Dendroica palmarum palmarum (Gmel.).— Recorded

from Isle of Pines by Cory and found there in March, 1902, but

not on the second trip.

105. Seiurus noveboracensis (Gmel.).— Recorded by Poey

and seen in March, 1902.

106. Teretistris fernandine (Lembeye). “ CHINCHILETA."

— This beautiful little ground warbler inhahits the thick, dense

woods and is probably commoner than it appears to be. It was

not often seen, however.

Three specimens, two males and a female, were taken at Pas-

adita and Callebonita, in May and June. These are precisely

like Cuban ones. -

107. Geothlypis trichas (Linn.). — Recorded by Poey from

Isle of Pines. The subspecies to which this record applies is of

course somewhat uncertain. Ridgway identified a series of birds

taken in western Cuba by Palmer and Riley as ignota, and all

No. 460.] BIRDS OF THE ISLE OF PINES. 2TI

birds from eastern Cuba as brachidactyla. Judging from this the

form wintering in the Isle of Pines should be zgxota.

108. Setophaga ruticilla (Linn.). — Recorded by Poey, and

' found quite commonly in March, 1902. None were observed in

April, 1904.

109. Holoquiscalus gundlachii (Cassin). * CHICHINGUACO.”

— Common in more open country, pastures, and ploughed fields.

When the natives are ploughing, the grackle, often in great

numbers, follows the plough to pick up grubs and the like that

are turned up. It also, like the Ani, alights on the backs of

horses and cattle to pick off ticks. The male, owing to the ver-

tically placed feathers in the tail, presents a curious appearance

when on the wing.

Nine specimens, both sexes, were taken, all at Santa Fé in

April and May.

These skins average a little smaller with smaller bills than

Cuban ones, and are, perhaps, a trifle duller in coloration, but

in all these points Cuban birds vary, and there does not appear

to be any real character by which the Isle of Pines grackle can

be distinguished.

The series measures as follows : —

Exposed

No. Sex. Wing. Tail. Tarsus. culmen.

13,274 d ad. 137 120 36 33

13275 : d ad. 139 122 N- 33-5

13,276 d ad. 140 128 36 33-5

13,277 d young ad. 135 115 35-5 34

13,278 d young ad. 131 107 34-5 33

13,279 d young ad. 136 110 37 33

13,281 9 ad. 135 107 35 31-5

13,282 Q ad. 123 102 32 28

110. Ptiloxena atroviolacea (d'Orb.). ' “ Tori." — Probably

a rare bird in the Isle of Pines as none were observed. The

natives, however, know the * Toti” from the “ Chichinguaco."

It is recorded from the island by-Poey and by Gundlach.

111. Icterus hypomelas (Bonap.). “Sorısıa.’— Common,

especially among the pines. The oriole feeds-a good deal

among the flowers of various shrubs and trees, and its head is

often daubed with juice and pollen from these.

212 THE AMERICAN NATURALIST. (VoL. XXXIX.

Fourteen specimens, adults of both sexes and young including

nestlings, were taken at Jucaro, Hospital, Callebonita, and Santa

Fé in April, May and June. In birds from the Isle of Pines the

yellow color of rump, thighs, and wing-coverts is a little paler

than in Cuban examples, as is also the brownish yellow of under

tail-coverts and anal region, with less of this color and rather

more black than in Cuban specimens; but these differences are

not very tangible and the Isle of Pines bird is not different

enough to be formally separated as a subspecies.

112. Agelaius assimilis Lembeye.! “Tori LA CIENAGA."

— During the period spent near the Cienaga — April and

May — all the birds of this species, that probably at some time

of year scatter through the swamp to breed, were congregated in

one flock that kept to some large trees at the edge of the

Cienaga. The breeding season was not near at hand as the

testes of the males were not enlarged, neither had it just passed

as no very young birds were seen.

The notes of this species resemble those of the common Red-

wing (Agelaius pheniceus) but are lower and more wheezy,

sounding, when a number are calling together, much like the

chirping of insects.

In the adult male the wing is colored like that of A. phaniceus

floridanus, but younger males have the shoulder black, as in the

adult female, except that some of the feathers are irregularly

tipped and spotted with red and tawny, the amount of these

colors varying much, from individuals with scarcely any to those

that begin to show the characteristic markings of the adult.

Of all the Icteride this is probably one of the rarest and

most local species, being known only from the Zapata Swamp in

Cuba and the Cienaga in the Isle of Pines.

Seven specimens, both sexes, were taken, all at the edge of

the Cienaga in April.

113. Sturnella hippocrepis (Wagler). **SABANERO."— The

Meadowlark is common in pastures and fields and in the edge of

the pine woods, and is very tame and unsuspicious.

Six specimens, adults of both sexes, were taken at Santa Fé,

1 Ex Gundlach, MSS.

No. 460.] BIRDS OF THE ISLE OF .PINES. 213

Jucaro, and Callebonita in April and May. These are similar to

Cuban specimens, although they average more yellow on the

thighs. Some Cuban skins, however, have the thighs nearly as

yellow as Isle of Pines birds.

114. Dolichonyx oryzivorus (Linn.). — A casual migrant to

the Isle of Pines, recorded by Cory and by Gundlach, but not

observed on either trip.

115. Spindalis pretrei pinus subsp. nov.

* CABRERO.”

Type from Santa Fé, Isle of Pines, adult male, no. 13,317,

Coll. of E. A. and O. Bangs. Collected April 18, 1904, by

W. R. Zappey. :

Characters. — Similar to true Spindalis pretrei (Lesson) of

Cuba, but considerably larger with a larger bill. There is also

a slight average difference in color, the male of the new species

being rather paler and more purely yellow, less rufous-orange

and tawny-orange, on nuchal collar, lower rump, and chest, than

in Cuban examples; and the black cap extends rather farther

backward, encroaching more upon the yellow of the nape band.

The female appears not to differ in color, though our specimens

are slightly paler and grayer than Cuban ones, but they were all

taken in spring and early summer, whereas the Cuban examples

we have compared them with were shot in December. The dif-

ference therefore is probably seasonal.

Measurements : —

Exposed

No. Sex. Wing. Tail. Tarsus. culmen.

13,311 ad 75 57-5 18.5 12.5

13,312 ad 74-5 57 18 17:5

13,323 ad 76.5 59 18.5 13

13,314 ad. 77 57-5 18 12

13,315 ad. 71 54 19 12

13,316 ad. 73-5 56.5 19 12

v p

Oy Oy Oy Oy Dy Ox Oy Oy OS Os OF

pop

A A A e

* e LI .

—

—-

214 THE AMERICAN NATURALIST. [Vor. XXXIX.

Exposed

No. Sex. Wing. Tail. Tarsus. culmen.

13,322 d ad. 75 57-5 18 12

13,310 Q ad. 69 94 17.5 12

13,313 9 ad. 68 - 2 17 I2

13,324 9 ad. 69 50 17.5 12

13,325 2 ad. 71 55.5 18 12

13,326 9 ad. USB 53 17.5 12

13,127 9 ad. 67 53-5 II

13,328 Q ad. 69 Le 18 13%

13,329 9 ad. 67 50 17 12

13,330 9 ad 2 2 18.5 11.5

The Spindalis is a conspicuous and rather common bird in

the Isle of Pines, frequenting the pines and a tree (name not

known) that bears a pink blossom. Both the males and females

sing, the song being a low, weak warble.

Twenty-one specimens, adults of both sexes, were taken at

Santa Fé, Jucaro, Callebonita, Pasadita, and San Juan, in April,

May, and June. These differ from Cuban examples, as has

been pointed out by Ridgway in Birds of North and Middle

America, in larger size and bigger bills, and in addition show a

slight average difference in color.

116. Tiaris olivacea olivacea (Linn.). | * TOMEQUIN DE LA

TIERRA.” — A rather common bird in the Isle of Pines, in the

brushy country, and particularly fond of thorn bushes, and one

species of palm upon the berries of which it feeds.

Nine specimens, adults of both sexes, were taken at Santa Fé

and Callebonita in April, May, and June.

Ridgway in Birds. of North and Middle America (Part I, p.

531, footnote) speaks of the slightly larger size and duller colors

of the male Grassquits from Cuba, Grand Cayman, and Little

Cayman as compared with those from Haiti and Jamaica. The

series from the Isle of Pines bears out both peculiarities —

larger size of the males and duller colors — but the differences

are very slight and hardly sufficient to base a new form upon.

The specimens measure as follows : —

pert cena

No. Sex. Wing. Tail. Tarsus. culmen.

13,301 d ad. 49 37-5 15.5 9

13,303 d ad. 47:5 37-5 16 9

13.304 d ad. 49.5 38 15.5 9.5

No. 460.] BIRDS OF THE ISLE OF PINES. 215

No. : Sex. Wing. Tail. Tarsus. ey sag

13,306 d ad. 51.5 40 16 9

13,307 d ad. 50.5 39 15.5 9

13,308 d ad. 50.5 * 38.5 15.5 9

13,309 d ad. 52 41 15.5 9.5

13,302 9 ad. 47 37.5 15 9

13.305 9 ad. 47 36 15.5 8.5

117.? Tiaris canora (Gmel.). “ TOMEQUIN DEL PINAR."—

Under the name Passerina collaris Vig., a synonym of the Melo-

dious Grassquit, Poey recorded this bird from the Isle of Pines.

Cory also gives the species from the island, but may have taken

it directly from Poey. Poey does not include the common Yel-

low-faced Grassquit in his list, and we consider this a very

doubtful record probably due to confusion of names.

At all events, it must be very rare, as nothing was seen

or heard of it in the Isle of Pines by Palmer and Riley or by

Zappey. ;

118. Melopyrrha nigra (Linn.). “ NEGRITO."— The Cuban

Bullfinch appears to be restricted in the Isle of Pines to the :

dry, brushy country south of the Cienaga and even there is not

at all common.

One male was taken at Puenta del Este, on April 29.

119. Passerculus sandwichensis savanna (Wilson).— The

Savanna Sparrow was taken in March, 1902, but on the second

trip to the island, beginning in April, none were seen.

120. Coturniculus savannarum passerinus (Wilson). —

The Yellow-winged Sparrow was also found in March, 1902, and

was not observed during the 1904 trip. None appear, there-

fore, to breed in the Isle of Pines, and those seen in March,

1902, undoubtedly were northern birds. There is, however, a

resident breeding race in Cuba, as well as northern birds that

pass the winter there.

STUDIES ON THE PLANT CELL. —.V.

BRADLEY MOORE DAVIS.

Section IV. CELL UNIONS AND NUCLEAR FUSIONS IN

PLANTS.

Tue forms of cell unions and nuclear fusions in plants fall

into two groups: (1) those which obviously have no sexual sig-

nificance attached to them, and (2) those which are evidently

sexual acts. But apart from these simple divisions there are

some very interesting conditions in which it. is far from easy to

determine whether certain events have a sexual significance either

physiologically or phylogenetically. The real test of such prob-

lems should lie in the evolutionary history of the processes

involved, for every sexual condition in plants has probably

developed in obedience to the same physiological demands and

in an essentially similar manner. However, we cannot apply the

evolutionary test in many cases where we have little evidence of

the developmental history of the group and such forms must rest

for the present as unsolved problems. We shall treat them in

special connections later in the paper.

The material of this section will be presented under the fol-

lowing heads : —

t. Protoplasmic connections between cells (plasmodesmen).

2. Sexual cell unions and nuclear fusions.

3. Asexual cell unions and nuclear fusions.

1. Protoplasmic Connections between Cells (Plasmodesmen).

It has been known for a great many years that the walls-

between the cells in some, plant tissues and more especially

between the cells of filaments in certain thallophytes were

crossed by delicate strands of protoplasm so that contiguous pro-

toplasts were not entirely separated from one another. This fact

217

218 THE AMERICAN NATURALIST. | (Vor. XXXIX.

offers at once many interesting possibilities of explaining the

close association of many cells and tissues, not alone in delicate

dynamic interrelations but even in the exchange and distribution

of food material and other products of metabolism. - It makes

possible the conception of the plant body as a finely adjusted

community of protoplasts intimately and sensitively related to a

great degree in all parts, a view very different from the old idea

of a cell republic. As might be expected, these speculative

possibilities were conceived and expressed by such leaders as

Hofmeister, Nägeli, Sachs, and Strasburger long before the

detailed study of protoplasmic connections gave the mass of evi-

dence upon which have been based the more elaborate concep-

tions of recent years.

The most obvious protoplasmic connections between cells may

be found in the thallophytes where as in the Rhodophycee,

Volvox, and in certain fungi, the cells in younger structures may

be observed under comparatively low magnification to be united

by strands of protoplasm so broad as to quite exclude them from

the category of fibrille. Some of these structures are so con-

spicuous that it is surprising that more was not made of them by

early writers and that they have not been more extensively

investigated recently. The greater part of the papers have

been on the very difficult phase of the subject, the structure of

pores and pits in the tissues of higher plants. The literature

treating of protoplasmic connections is too extensive to be given

detailed treatment in the compass of this paper. The best

review of the subject is that of Strasburger (: o1), supplemented

by the more recent paper of Kienitz-Gerloff (: 02).

The earlier papers on the protoplasmic connections in higher

plants, following the establishment of perforations of sieve-plates

by Sachs and Hanstein, appeared during the years just preceding

and following 1880. Thus Tangl ('79—81) described very clearly

the communications between the endosperm cells of Strychnos

nux vomica and Phoenix (see Fig. 16, a). Tangl noted the resem-

blance of the complex of connecting threads to the arrangement

of spindle fibers associated with the simultaneous division of the

protoplasm in the endosperm but was cautious in assuming a

relationship, suggesting that the resemblance might be super-

ficial.

No. 460.) STUDIES ON PLANT CELL.—V. 219

Strasburger (82, p. 246) discussed the permeability of cell

walls and Gardiner (88) gave a general treatment of the subject

without, however, any figures to illustrate his conclusions.

Gardiner discovered for a large number of forms in a wide

variety of families that the pit membranes were frequently

pierced by protoplasmic fibrils and that in some cases the fibrils

traversed the entire thickness of the cell wall. A more detailed

study with better methods, supplementing his former work and

accompanied by figures, was published by Gardiner, in 1898,

this paper forming an important contribution to the subject.

Gardiner (:00) announced himself strongly in favor of the view

that the protoplasmic connections between cells were derived

from spindle fibers of nuclear figures concerned with each cell

division, a possibility which had been suggested by previous

writers (Tangl, '79-81; Russow, 83).

Kienitz-Gerloff ('91) gave an excellent account of the proto-

plasmic connections in a number of forms, some of them

pteridophytes, but especially for Viscum album, and followed the

history of the wall formation, showing that the spindle fibers

disappeared completely before the development of the connect-

ing strands of protoplasm. Kuhla (: oo) followed Kienitz-

Gerloff with more extended studies on the same form, Viscum

album, tracing the protoplasmic fibrils between the cells in all

" the chief tissues and establishing the protoplasmic connections

throughout the individual to an extent that was not known

before. Hill (:01) described the structure of the sieve-tubes of

Pinus, dealing especially with the formation of callus and the

conversion of the connecting threads of protoplasm into strings

of slime. An excellent review is also given of the work of

Russow and others, particularly upon sieve-tubes. Kohl (97)

describes clearly protoplasmic connections between the cells of

moss leaves. :

A classification of protoplasmic connections was suggested

by Kohl (: 00) who distinguished between the solitary state when

each fibril pierces the cell wall independently of its neighbors

(Fig. 16, a and b) and a grouped condition when a number of

fibers arise close together at the bottom of a pit and pierce the

pit-membrane or middle lamella in a spindle-shaped arrangement,

220 THE AMERICAN NATURALIST. (VoL. XXXIX.

reminding one of the central spindle of a mitotic figure (Fig.

16, c). In general the two types of protoplasmic connections are

not found together in the same cell or tissue.

A new point of view was introduced into the discussion by

the very important paper of Strasburger, in 1901. He consid-

ered the protoplasmic connections as sufficiently clearly differ-

entiated structures to rank as organs of the cell and proposed

for them the name plasmodesmen. Strasburger in agreement

MEZ

clamp connections in Pleurotus (a, after ak Fee: 6 and c, Kohl, :00; d, Davis

'96 b; e, Kohl, :02; /, Thaxter, '96 ; & Meyer, :02). ;

with Kienitz-Gerloff opposed the view that the plasmodesmen

were in any way derived from or related to the spindle fibers

associated with the formation of cell plates. He believed them

to be developments of the outer plasma membrane as he like-

wise considers the cilia in certain zoöspores (see account of

zoöspore and sperm in Section III, Amer. Nat. vol. 38, pp. 571,

576, 1904). Strasburger also holds that pores are formed in the

cell walls by the fermative activities around plasmodesmen. A

No. 460:] STUDIES ON PLANT CELL.—V. . 221

recent short paper by Michniewicz (:04) describes clearly the

plasmodesmen in Lupinus, especially in their relation to masses

of intercellular protoplasm which are discussed at the end of

this portion of the section.

It is not clear whether all protoplasmic connections may be

considered in the same class, as Strasburger would have us

believe, or whether there may not be some confusion between

the broader cell connections which are especially conspicuous in

the thallophytes and certain tissues (sieve-tubes, laticiferous

vessels), and the delicate protoplasmic fibrils (plasmodesmen) so

general throughout all tissues of higher plants. As is well

known, the cells in actively growing regions of the red algze are

connected by broad strands of protoplasm that are obviously

left by the cleavage furrow which constricts the protoplasm of

daughter cells but does not entirely separate them. These open-

ings may become partially blocked in older portions of the plant

by the deposition of material so that the connections are finally

fibrillar but they frequently remain open for long periods, par-

ticularly in regions where the nutritive processes are active as

during the development of cystocarps. At this time new

fusions may be developed between neighboring cells (auxiliary

cells) so that they become connected in an elaborate network

around the cells or filaments (sporophytic) that develop the car-

pospores (Fig. 16,d). The Phaeophycez also furnish frequent

illustrations of connecting fibrils especially in the Fucales and

Laminariales where the cells of internal filaments are sometimes

connected by conspicuous strands. Certain elongated filaments

which traverse the central region of the larger brown algae show

a complicated group of fibrils that strikingly resembles the pro-

toplasmic connections piercing the sieve-plates of higher plants.

Broad protoplasmic connections are conspicuous between the

cells of some of the filamentous Cyanophycez (Stigonema,

Tolypothrix) and in the Chlorophycez have been reported for

some species of Cladophora (Kohl, :02; Fig. 16, e) and for

Chaetopeltis, one of the Mycoidee. They do not seem to be

present in the Conjugales as was at first reported by Kohl

('91) whose cells show a great degree of physiological inde-

pendence. In Volvox, studied by Meyer (96), each cell of the

222 . THE AMERICAN NATURALIST. | [Vor. XXXIX.

splíere is connected with its neighbors generally by six strands

of protoplasm, only a few of which could possibly be left by the

successive cell divisions. The majority must have developed as

outgrowths from the plasma membrane of the cell.

Numerous instances of cytoplasmic connections among the

fungi have been reported by many authors. A general review

of the subject is presented by Kienitz-Gerloff (:02) and in a

lengthy paper of Meyer (:02). The protoplasmic connections

fall into two groups: (1) those that remain in the center of the

wall after a cell division, and (2) the lateral unions and clamp

connections which are developed entirely independently of cell

division. Connections of the first type, 7. e., those between

daughter cells, appear to be very general in the Ascomycetes

and Basidiomycetes and are essentially similar to the strands

between cells of the Rhodophycea. They are especially well

illustrated in members of the Laboulbeniacee (Thaxter, '96;

see Fig. 16,f). In the second group are the clamp connections

(Fig. 16, g), characteristic structures of the tissues of fleshy

forms of the Basidiomycetes, and the lateral unions between

cells of closely entangled hyphæ which are well known in a

number of forms and have been followed in cultures from germi-

nating spores. It is probable that the fusions between sporidia

in the smuts are also of this class, although De Bary and others

have attached sexual significance to the phenomenon (especially

as illustrated by Tilletia). Harper (99a) has studied the fusions

of the conidia of Ustilago and finds that they concern the cyto-

plasm alone. However, Federley (:03-:04) has reported a

nuclear fusion in one species (Ustilago tragopogonis pratensis

Pers. but states that others agree with Harper's account.

Extensive experiments of Brefeld have shown that the fusions

of sporidia depend largely upon the character of the nutrient

media and are less likely to occur when the conditions are favor-

able. He considers the fusions as purely vegetative processes

comparable to the unions of germ tubes of spores (e. g., Nec-

tria, Sclerotinia, Rhyparomyces, etc.) into a common mycelium

and to the connections between hyphz of Basidiomycetes.

Recent studies of Blackman (:04.a) indicate: also that sexual

processes should not be expected at this period in the life his-

No. 460.] STUDIES ON PLANT CELL—V. 223

tory of smut or rust. One of the best discussions of cell

fusions in the fungi is that in Harper's paper (99a), noted

above.

Although most of the protoplasmic connections in higher

plants are of the fibrillar character there are some notable illus-

trations of broad openings between cells, even more conspicuous

than those in the red algae. Such may be found in the pores of

sieve-plates traversed in their early stages by strands of proto-

plasm that later disappear, and even better illustrations are the

unions between cells composing laticiferous vessels. But the

most interesting conditions are those associated with the nutri-

tion of the eggs of certain cycads. Goroschankin (83) first

noted for the cycads pores or canals in the egg-wall of Ceratoza-

mia and described communications between the protoplasm of

the enveloping cells of the jacket and the egg. The subject is

closely associated with the explanation of the proteid vacuoles in

the eggs of gymnosperms which Arnoldi believed to be nuclei

that had migrated from the surrounding cells. The conclusions

of Arnoldi have not been sustained (see Sec. III, Amer. Nat., vol.

38, pp. 591, 592, 1904) but the presence of pores in the egg-wall

gy perms is likely to prove very general with further

investigation. A recent paper by Miss Isabel Smith (:04) gives

an account of haustoria-like processes from the egg of Zamia

which pass through the pores of the egg-wall into the cells of

the jacket, where they are in direct contact with its protoplasm.

These pseudopodia-like processes of the egg apparently absorb

material from the cells of the jacket as is indicated by the char-

acter of their staining and the streaming movement towards

them of the protoplasm in the jacket cells. The relation of the

plasma membrane of the processes from the egg to that of the

jacket cells is not clear but probably they are merely in contact

and not in open communication. The ovules of cycads seem to

offer an especially favorable subject for the study of pore forma-

tion and the intimacy of protoplasmic connections between cells.

It seems very clear that the cytoplasmic connections in the

Rhodophycez, Volvox, fungi, and between the egg and jacket

cells of cycads involve very much more substance than is gen-

erally present in the delicate- fibrille of higher plants. Meyer

224 THE AMERICAN NATURALIST. | [Vor. XXXIX.

(102, pp. 167, 168) seems justified in emphasizing their resem-

blance to pseudopodia rather than to any other structure of the .

cell. If they should finally be connected by intergradations

with the exceedingly fine plasmodesmen of Strasburger, there

would stand at one end of the series structures so thick as to

be composed of a plasma membrane containing much cytoplasm

in the interior and behaving like haustoria or pseudopodia and

at the other end delicate fibrille. Viewing the problem of their

relationships from the lower plants upwards, it is very difficult,

if not impossible to follow Strasburger's theory that all cytoplas-

mic connections (plasmodesmen) are related to developments -

from the plasma membrane similar to cilia. They seem to be

more of the nature of processes put out from the cytoplasm and

when necessary penetrating cellulose walls probably in response

to chemotactic stimuli since they are most conspicuous when

metabolic. activities are obviously important (e. g., nourish-

ment of the egg in gymnosperms and sporophytic ee

of the red algae).

In method of development we have seen that protoplasmic

connections fall into two classes: (1) those that represent the

incomplete separation of daughter cells, and (2) those that

result from the coming together or fusion of protoplasmic out-

growths. The types of the first group are always in the be-

ginning open communications which later may become largely

or wholly closed ; types of the second group may result in broad

cytoplasmic fusions (e. g., many fungi) but there is evidence

that in many cases, especially among the higher plants, the two

processes only come in contact so that the plasma membranes

are applied to one another but do not actually unite. It does

not seem probable that the two methods of development or the

presence or absence of intimate protoplasmic union indicate a

different kind of structure. They are more likely to be only

varied responses to the demands for a more or less close associa-

tion of neighboring cells. Broad communications are especially

characteristic of regions where there is evidently an extensive

demand for the nourishment of a cell or tissue, as in the eggs of

the cycads or the cystocarp of the red alga.

The functions of protoplasmic connections are probably vari-

No. 460.) STUDIES ON PLANT CELL.— V. 225

ous. It is evident that they bind the whole plant body into a

cell complex capable of very delicate interrelations. It is

natural that physiologists, Pfeffer and others, should associate

the structures with the phenomena of irritability as the paths

over which stimuli may be transmitted from cell to cell and

tissue to tissue. Several writers have reported their presence in

unusual numbers in irritable structures of plants. The subject

is discussed in great detail by Strasburger (:01, p. 533).

Besides conducting stimuli, there is much evidence that

material may be transferred in solid or semifluid form by the

-protoplasmic connections from cell to cell and that in some

instances there is actually a movement or flow of protoplasm.

It is even known that nuclei may pass from cell to cell through

pores in the wall, especially after some shock, as in the neigh-

borhood of wounds (Miehe, : 01), or when temperature is sud-

denly raised (Schrammen, :02). This literature and other

references are discussed by Koenicke (:01; :04). A flow of

protoplasm between neighboring cells of hyphz has been

reported by Reinhardt (92) and Charlotte Ternetz (:00).

That nuclei may pass through very small space is shown

in the development of spores in the Basidiomycetes and in

the growth of haustoria from the cells of hyphze (Smith, : 00).

There are many forms known, especialy among the thallo-

phytes, where the communications between cells are so broad

as to admit of a very free circulation of their contents. Such

conditions are especially well illustrated in tissues around the

developing cystocarps of the Rhodophycez and the ascocarp

of the Ascomycetes, both structures apparently sporophytic in

charater and dependent to a great degree upon the gametophyte

asa host. It is believed that the vitality of protoplasm in sieve

tubes, whose nuclei have degenerated and disappeared, is main-

tained through protoplasmic connections with neighboring cells

and especially ' the companion cells, when present. Of course

where an actual circulation of protoplasm is established between

cells or tissues there is made possible a distribution of the

products of metabolism in solid form that is very different from

the usual diffusion in tissues through cell walls and plasma mem-

branes.

226 THE AMERICAN NATURALIST. [Vor. XXXIX.

It seems probable that there are really two forms of proto-

plasmic connections between cells in plants: first, those so

intimate that the plasma membranes are pierced and become

continuous openings inclosing a strand of granular cytoplasm

within; and second, those -in which the plasma membranes are

merely applied to one another without open communication.

The second form comprises the most delicate connecting fibrillz, |

structures so fine that their minute structure is not understood

and we do not know how intimate may be the application of the

fibrillae to one another or to the surface of the cells. These are

the typical plasmodesmen of Strasburger which he considers as

organs of the plasma membrane, kinoplasmic in character, and

compares to cilia. The broad connections of the first group

have exactly the structure that would be expected of fused

pseudopodia, as Meyer pointed out. Whether the two types

insensibly grade into one another or whether each is a develop-

ment by itself is a problem of considerable interest, for if the

former possibility prove true, Strasburger's conception and clas-

sification of plasmodesmen as organs of the cell will hardly

seem justified.

When protoplasmic connections become so broad that cyto-

plasm flows or surges from one cell to another, an actual transfer

of nuclei sometimes takes place. Such conditions may illustrate

simply one extreme of the series of protoplasmic connections

that we have just discussed, but many of them introduce some

complexities, mainly through a certain resemblance to sexual

processes, so that they should be treated apart from general

protoplasmic connections. Some of them will be described later

under the head of * Asexual Cell Unions and Nuclear Fusions.”

Closely associated with protoplasmic connections is the inter-

esting subject of intercellular protoplasm which is receiving

some attention at present. The last papers are by Kny (:04)

and Michniewicz (:04) who are studying conditions in the seed,

especially of Lupinus. By various reactions and physiological

studies, Kny has established an apparent identity of nature

between an intercellular substance, sometimes with starch

inclusions, and the cytoplasm of the neighboring cells. He

considers this substance to be intercellular protoplasm, that is,

No. 460.] STUDIES ON PLANT CELL.— V. 227

protoplasm outside of the cell walls, but connected with the

cytoplasm within through fibrille. The intercellular proto-

plasm is thus conceived in organic connection with nucleated

cells and from the studies of Townsend (97) we know that non-

nucleated protoplasm may live so long as it is united with

nucleated, even though it be by very delicate fibrille. Michnie-

wicz (:04) confirms Kny's conclusions for Lupinus and gives a

very clear account of the fibrille which connect the masses of

intercellular protoplasm with neighboring protoplasts. These

studies make clearer a number of observations of several inves-

tigators (Sauvageau, Buscalioni, Schenk, Magnin, Strasburger, -

and others) who have noted similar conditions in the tissues

of higher plants which are being investigated in detail by Kny.

Some of the lower unicellular forms likewise exhibit an extra-

cellular surrounding film or envelope, which may also be of a

protoplasmic nature and consequently in the same position in

relation to the protoplast as intercellular protoplasm. Thus it

has been known for many years that the cells of the Peridinales,

diatoms, and desmids possessed extracellular material, which

some authors have considered in the nature of slimy excretions

but others — Schutt ('99; : 00a; : 00b), Hauptfleisch ('88 ; '95),

Müller ('98—99) — have regarded as protoplasmic in character.

Since the cell walls in these forms are known to possess pores,

such extracellular substance must be in close association with

the cytoplasm of the cell and it is not at all difficult to conceive

of it as a part of the protoplasm. Some of the peculiar creep-

ing movements of the diatoms and desmids are perhaps expli-

cable upon these facts.

2. Sexual Cell Unions and Nuclear Fusions.

The test of a sexual act must lie with the history of the ele-

ments which fuse. If these are shown by their morphology and

developmental history to be sexual cells or gametes then their

fusion becomes a sexual process. There are cell and even

nuclear fusions which have the physiological appearances of

sexual acts but cannot be so considered because the elements

concerned have plainly no relation to sexual cells, which are

228 THE AMERICAN NATURALIST. (VoL. XXXIX.

developed at other periods of the life history, or to the primitive

conditions always found with the origin of sex. These exceptional

processes will be collected and described under the heading

* Asexual Cell Unions and. Nuclear Fusions," following this

portion of the paper.

The union of gametes is generally termed fertilization. The

evolution of the sexual process always tends towards a differ-

entiation of the two sexual cells, one becoming more richly

stored with food material and containing more protoplasm than

the other. This latter gamete is always considered the female

and is said to be fertilized when the male gamete, either as a

motile sperm or reduced simply to a sperm nucleus generally

with some accompanying protoplasm, fuses with it. The most

evident morphological feature of fertilization is the close union

of the gamete nuclei so that the chromosomes of both enter into

the mitotic figure with which the new generation begins.

We sball not discuss the various forms of gametes nor their

habits in different types of sexual reproduction. They have

been described in two articles by the author on the origin and

evolution of sex in plants (Davis, :01; :03). A detailed ac-

count of the sexual reproduction of well known types through-

out the plant kingdom has been recently published by Mottier

(:04b) under the title * Fecundation in Plants" a term which

he prefers to fertilization. This paper gives in English the

most extensive summary of our knowledge of the subject up to

the date 1902 and will be read with especial interest as the

most available expression in English of Strasburger's general

views on the significance of the events connected with sexual

reproduction.

A recent paper of Guérin (:04) is confined to an account of

fertilization in the phanerogams which are treated in considerable

detail. His discussion of double fertilization and parthenogene-

sis is of especial interest and will be taken up later.

Our purpose is to divest from the events of sexual cell unions

and nuclear fusions all secondary and unessential processes and

to outline, as are now understood, the fundamental phenomena.

And to make the subject more plain we shall try to compare

in their essentials the events of fertilization in plants with those

No. 460.] STUDIES ON PLANT CELL— V. 229

in animals. Probably the most important feature of fertilization

is the close union of the gamete nuclei through which the

chromosomes of both enter into the first mitotic figure of the

new generation. It involves the organization of the first cleav-

age spindle, which inaugurates the new generation, and the his-

tory of the paternal and maternal chromosomes of the gametes

at this time when the number becomes doubled.

Several zoólogical papers have developed in the past few years

some very important conclusions concerning the individuality of

the paternal and maternal chromosomes, as maintained during

the fusion of the gamete nuclei and in the formation of the first

cleavage spindle. It has been generally believed for some time

— see general review in Wilson (: 00, p. 204) — that the fusion

of gamete nuclei did not involve a coalescence öf the chromo-

somes but that both paternal and maternal chromosomes main-

tained complete independence of one another and that all entered

into the first cleavage spindle as structures quite as distinct as

when formed during spermatogenesis and oógenesis. Hacker

and Rückert have shown for Cyclops that the gamete nuclei

divide side by side in the first mitosis following fertilization, and

Häcker followed these double nuclei as far as the 16-celled stage

when they were still distinct from one another. A few notable

investigations of recent years have identified chromosomes accu-

rately as maternal and paternal not only in the first cleavage

spindle but through certain succeeding mitoses and finally at

the period of gametogenesis when sperm and egg were again

formed. The above principles have been established chiefly

through a series of papers of Montgomery, the chief being a

lengthy. investigation of 1901, and contributions of Sutton

(102; :03) and Moenkhaus (:04). They have given us clear

evidence that the chromosomes not only maintain their com-

plete individuality throughout successive generations but are

distributed with gametogenesis and fertilization in various pos-

sible combinations that can be expressed by mathematical for-

mula furnishing the basis for certain ratios that approximate

the teachings of Mendel’s law. We shall have occasion to refer

to these in Section V when the subjects of gametogenesis, reduc-

tion of chromosomes, and hybridization will be discussed. -

230 THE AMERICAN NATURALIST- (VOL. XXXIX.

The same principles have been established in plants by recent

investigations, some ot which deal with oógenesis and spermato-

genesis and will be specially treated in the Section V while others

treat of the behavior of the chromosomes when the gamete nuclei

fuse and the sporophyte generation begins its development. The

latter conditions concern the present discussion.

The history of the chromosomes in plants at the time when

the gamete nuclei fuse (fertilization) is most accurately known

for the pine. The last paper upon this type (Ferguson, 104) is

very complete. Miss Ferguson gives a beautiful series of figures,

some of which we have reproduced. The sperm nucleus comes

in contact with the egg nucleus and sinks into the latter so that

it lies in a depression, but as noted by Blackman (98), it does

not penetrate the membrane of the egg nucleus (Fig. 17, a).

Both gamete nuclei thus lie side by side occupying approxi-

mately the same space formerly filled by the female. Each

shortly gives evidence of preparation for the mitosis following

fertilization (first cleavage spindle). The chromatin of the egg

nucleus collects in a spirem, very close to the sperm, occupying

a relatively small portion of this large female nucleus (Fig. 17, b).

The chromatin of the sperm nucleus also takes position as a

spirem on the side nearest its companion chromatin of the oppo-

site sex. The remaining space of each nucleus is filled with a

granular reticulum of a linin nature. At this time the amount

of linin is extraordinarily large in proportion to the chromatin,

suggesting that some of the latter substance has become changed

to the former. Soon, delicate fibrillae appear around the two

spirems growing outward in various directions and finally cross-

ing from one nucleus to the other. At the same time the two

nuclear membranes become less distinct and shortly disappear.

Thus the maternal and paternal spirems come to lie in a com-

mon area filled with delicate fibrille which run out to the gran-

ular cytoplasm that lay around the two gamete nuclei (Fig. 19,6).

It should be especially noted that at no time in this history has

there been a resting nucleus including both maternal and pater-

nal chromosomes within a common nuclear membrane. The

fusion of the gamete nuclei has only come with the actual

formation of the first cleavage spindle.

No. 460.] STUDIES ON PLANT CELL.— V. 231

The fibrille organize a multipolar spindle which is very vari-

able in form, sometimes with broad poles of a multipolar diarch

(Fig. 17, d) and at other times almost as pointed as in a typical

bipolar spindle (Fig. 17, e). There are, of course, no centro-

somes and the entire spindle in essentially of intranuclear origin.

The history of its development recalls Miss Williams’ account

of the spindle in the pollen mother-cell of Passiflora (Sec. III,

Amer. Nat., vol. 38, p. 738, 1904). During spindle formation

the spirems of the sperm and egg nuclei can be readily distin-

guished as was described by Blackman (98) and Chamberlain

Fic. 17. — Fertilization in Pinus strobus. a, conjugating gamete nuclei; 4, > gamete nuclei

still rear with nuclear palate dis tinct, the maternal and paternal chroma atin in

two spire , the nuclear membranes have

together aa by the fibrilla which will organize the first segmentation spindle; d,

prophase of the first segmen ntation spindle, of the multipolar diarch type, paternal and

men spireins still distin; " — of fret ay entation mitosis, maternal a:

split in the middle region (after

Prison, : 104).

('99), but after the two sets of chromosomes are formed (twelve

of each) the latter are brought so closely together at metaphase

of mitosis that the paternal and maternal cannot be separated.

All of the chromosomes are exactly alike and there is nothing in

the form or size to distinguish one from another as certain

232 THE AMERICAN NATURALIST.: (VoL: XXXIX.

zoölogists have been able to do in some favorable animal types

(Montgomery, Sutton, Moenkhaus) The chromosomes divide

longitudinally in the usual way, the halves being drawn apart

from the points of attachment of the spindle fibers (Fig. 17, e).

It is clear that each daughter nucleus receives a full set of 24

daughter chromosomes, 12 of paternal and ı2 of maternal

origin, and that there is about an equal amount of chromatin

from each sex.

It should be especially noted that in the process of fertiliza-

tion in the pine there is at no time present wbat is generally

called a fusion nucleus, 7. e, a single nucleus whose membrane

incloses all the material of both male and female gamete nuclei.

Such fusion nuclei, as we shall see, have been reported many

times in other groups of plants than the gymnosperms where in

many cases, however, detailed studies are very difficult and can

scarcely be said to have even approached our knowledge of the

pine.

Studies of other botanists indicate that the gymnosperms

generally will show essentially the same conditions as in the

pine. Thus Woycicki ('99) distinguished in Larix two groups

of chromatin which he regarded as paternal and maternal. And

Murrill (: 00) states for Tsuga that the chromatin of sperm and

egg remain separate, forming two spirems, and only after their

segmentation into chromosomes are the two sets of structures

brought together in the first cleavage spindle. Land (: 02)

figured the sperm nucleus of Thuja imbedded in a depression of

the egg nucleus. Miyake (:03a) noted that the sperm nucleus

of Picea became more or less imbedded in the egg nucleus while

the nuclear membrane remained intact, and the same author

(Miyake, :03b), reports similar conditions in Abies. Robert-

son (:04) figures the sperm nucleus of Torreya lying within a

depression in the female and with a large amount of granular

cytoplasm (kinoplasm) at the side. Coker (103) states that

the partition between the gamete nuclei of Taxodium “ does

not entirely disappear until immediately before the first divi-

sion " although the two structures are closely united for some -

time previously while they pass to the bottom of the egg.

Lawson, studying Sequoia (:04a) reports gamete nuclei of

No. 460.] STUDIES ON PLANT CELL.—V. 233

about equal size whose chromatin contents unite in a fusion

nucleus to form a common network in which male and female

elements cannot be distinguished. A similar condition obtains

in Cryptomeria, according to Lawson (:04b), where a fusion

nucleus is described in which paternal and maternal chromatin

are mingled together in a nucleus that passes through a short

period of rest before the development of the first cleavage

spindle. In view of the work on Pinus I think it may safely be

questioned whether in Sequoia and Cryptomeria the maternal

and paternal chromatin really does form a common network in

the resting fusion nucleus. The subject is one very difficult of

study and demands more stages than Lawson seems to have

followed.

Fertilization in the cycads is not as completely known as for

the conifers. Webber (:01) figures the sperm nucleus of

Zamia imbedded in the egg nucleus but quite distinct from it as

in the pine but the further history leading to the development

of the first segmentation spindle was not followed. On the

other hand Ikeno ('98b) described in Cycas the formation of a

cup-ike depression in the egg nucleus to receive the sperm

nucleus which was said to enter and fuse completely with the

female and the same author (Ikeno, : or) reports a complete

fusion of the gamete nuclei in Ginkgo and did not distinguish

the paternal and maternal chromosomes during the formation of

the first segmentation spindle. However it is probable that

more detailed. studies among the cycads and in Ginkgo will

show a behavior of the sperm nucleus together with the pater-

nal and maternal chromatin essentially similar to that of the

conifers. All investigations among the cycads and in Ginkgo

agree that cytoplasmic structures of the sperm (blepharoplasts,

cilia, etc.) are left behind in the cytoplasm of the egg before the

mete nuclei unite. `

sperms is surprisingly meager. The only account of the chro-

matin is that of Mottier ('98 ; :04b, p. 176) for Lilium. He

describes and figures the two gamete nuclei as uniting with

their chromatin in the resting condition. The nuclear mem-

branes disappear at the surface of contact and the two nuclei

234 THE AMERICAN NATURALIST. | (Vor. XXXIX.

fuse into one. The nucleoli unite and so thoroughly does the

paternal and maternal chromatin seem to be mixed in the resting

condition that the fertilized egg nucleus can scarcely be distin-

guished from the unfertilized. There would seem to be then a

fusion nucleus in the lily with the chromatin in the resting

condition. The figures and brief accounts of other botanists

indicate that similar conditions may be expected in other angio-

sperms. But no one has followed the chromatin in the fusion

nucleus through its later history, during the organization of the

chromosomes preparatory to the first mitosis following fertiliza-

tion. It would be very surprising if paternal and maternal

chromatin did not remain entirely independent of each other

as in the pine. The detailed study of fertilization in the angio-

sperms presents a very attractive subject for investigation.

Some very interesting conditions of fertilization have been

Ib.

de -— deve ee 4, sperm as a spiral band within the egg nu-

distributed in the s "ida (after iie je Ace id tet hy

described in the pteridophytes for Onoclea by Shaw ('98 a),

confirmed by Mottier (:04a; :04 b) and for Adiantum and

Aspidium by Thom ('99). In these forms the male nucleus

after leaving in the protoplasm of the egg all of the cytoplasmic

structures of the sperm (blepharoplasts, cilia, etc.) enters the

egg nucleus as a more or less spiral body which stains deeply

and is evidently chiefly or wholly chromatic in composition (Fig.

18). Within the egg the dense structure of the sperm nucleus

becomes looser by the separation of the chromatin granules (Fig.

No. 460.] STUDIES ON PLANT CELL. V. 235

18, b) but the form of the sperm can be recognized fora long

time. The chromatin of the egg nucleus is in a resting condi-

tion at this period and the densely packed mass of paternal

chromatin is very conspicuous in the loose, delicate network of

the female chromatin. The mitosis following fertilization does

not occur for several days so that it is not easily studied and

the organization of the first cleavage spindle with the history of

the maternal and paternal chromosomes has never been followed.

But it is clear that we have in the pteridophytes a true fusion

nucleus containing for several days both maternal and paternal

chromatin within the same nuclear membrane.

There is only one paper that gives any details of fertilization

in the bryophytes, a contribution of Kruch ('90) on the liver-

wort, Riella, which seems to have been generally overlooked in

recent literature. After the sperm enters the egg, a male

nucleus is organized which increases in size until it is about

equal to the egg nucleus. The chromatin in both gamete nuclei

is described and figured as forming 8 chromosomes which are

organized before the fusion. The two gamete nuclei were

observed, but not figured, in contact and it was not possible to

distinguish in size the male from the female. This account is

then very different from those of the pteridophytes since the

sperm nucleus does not enter the egg nucleus but the two fuse

side by side and with their chromosomes fully organized. There

are, however, some points in Kruch’s paper that require more

extended investigation and confirmation in the light of modern

research.

There is left only the group of the thallophytes where less is

known about the detailed behavior of the chromatin during fer-

tilization than in any region of the plant kingdom. The conju-

gation of the gamete nuclei has been observed in a number of

thallophytes, representing all of the higher groups. All of the

authors, with the exception of Chmielewski ('90 b) for Spirogyra,

describe the product of conjugation as a fusion nucleus, 7. e.,

one in which the nuclear substance of both gametes is con-

tained within a common nuclear membrane. The most detailed

accounts of the fusion of gamete nuclei in the thallophytes are

those for Fucus (Strasburger, 97a; Farmer and Williams, ’98).

236 THE AMERICAN NATURALIST. Vor. XXXIX.

The sperm of Fucus upon entering the egg loses its cytoplasm

and passes rapidly to the egg nucleus as a deeply staining body

resembling a plastid in form. This structure is the male nucleus

whose chromatin is so densely crowded that it stains too deeply

to show much structure. Arriving at the side of the female

nucleus, about ten minutes after its entrance into the egg, the

male nucleus flattens against the female and increases in size so

that the chromatin appears less condensed. The male nucleus

is then absorbed so that the paternal chromatin lies within a

fusion nucleus but may be distinguished for some time as

densely staining material at one side. A second nucleolus

often appears in the fusion nucleus in the vicinity of the pater-

nal chromatin and is probably associated with the entrance of

the sperm nucleus, although it is not likely to have been brought

in as an organized structure but developed later at the expense

of material in the sperm nucleus. The fusion nucleus remains

quiescent for from 20 to 24 hours during which time the paternal

' chromatin becomes so distributed that it can no longer be fol-

lowed. Then two centrospheres with conspicuous radiations

appear at opposite poles of the fusion nucleus and the first

cleavage spindle is organized. There is no evidence that either

of these centrospheres is brought into the egg by the sperm and

both appear de novo and independently of one another.

The chief accounts of the fusion of gamete nuclei in thallo-

phytes are as follows: Closterium and Cosmarium (Klebahn,

'91); Rhopalodia (Klebahn, '906); Cocconeis (Karsten, :00);

Sphaeroplea (Klebahn, '99; Golenkin, '99); CEdogonium (Kle-

bahn, '92); Coleochzeta (Oltmanns, '98); Vaucheria (Oltmanns,

'95; Davis, :04); Fucus (Strasburger, '97a; Farmer and

Williams, '98); Batrachospermum (Schmidle, '99; Osterhout,

:00); Nemalion (Wolfe, :04); Basidiobolus (Fairchild, '97);

Albugo (Wager, ’96; Stevens, ’99,:01b; Davis, :00) ; Perono-

spora (Wager, :00); Pythium (Miyake, :01 ; Trow, :01); Ach-

lya (Trow, :04) ; Araiospora (King, :03); Sphzerotheca (Harper,

'95); Pyronema (Harper, :00). Most of these papers with

others on fertilization in the thallophytes are summarized by

Mottier, (:04 b) in very convenient form for reference.

There is some confusion in the accounts of fertilization in

No. 460.] STUDIES ON PLANT CELL.— V. 237

Spirogyra which should be thoroughly investigated. Chmielew-

ski (90b) in a paper published in Russian and reviewed in the

Bot. Centralb., vol. 50, p. 264, 1892, described a fusion of the

gamete nuclei in the zygospore and an immediate mitosis, with-

out a périod of rest, followed at once by a second division of the

daughter nuclei. These mitoses give the zygospore four nuclei,

two of which unite to form a final resting nucleus in the zygo-

spore while the remaining two fragment and their products

finally break down. This behavior offers an exception to all

sexual processes so far known in the plant kingdom. There are

some features which suggest a possible confusion with events as

described in the zygospore of the desmid and the auxospores of

certain diatoms.

The fusion nucleus in the zygospore of Closterium and Cos-

marium (Klebahn, '91) divides into four at the time of germina-

tion and two of these break down while each of the others

becomes the nucleus of the two new desmids that are formed.

There is then in the desmids the division of the fusion nucleus

into four but no secondary nuclear fusions as Chmielewski

reports for Spirogyra. In certain diatoms, Rhopalodia (Kle-

bahn, '96) and Cocconeis (Karsten, :00), there is a preliminary

division of the nuclei in each of the two cells which form the

auxospore. In Rhopalodia the mitoses are carried so far that

four daughter nuclei are formed in each diatom and the pro-

toplasm divides into two cells each of which fuses with a

corresponding cell of the companion pair. In both types the

superfluous nuclei break down so that the conjugating cells have

each a single functional gamete nucleus. There are then com-

plications in the Conjugales and the diatoms, which make nuclear

studies of the sexual processes exceptionally difficult and we seem

justified in reserving our judgment of the results of Chmielewski

until confirmed. It seems possible that the mitoses following the

germination of the zygospore in the Conjugales with the attend-

ant nuclear degeneration are reducing divisions in a simple and

primitive type of sporophyte generation but more detailed studies

of nuclear behavior during the formation and germination of the

zygospore will be necessary to settle the discussion.

We have now finished our account of nuclear fusions in the

238 THE AMERICAN NATURALIST. . [Vor. XXXIX.

sexual act (fertilization) but there remains for consideration the

behavior of certain cytoplasmic elements introduced into the

sexually formed cell, especially chromatophores and the blephar-

oplast. Since the blepharoplast bears a very close resemblance

tothe middle piece of the animal spermatozoon, which some-

times becomes a centrosome in the animal egg, a critical com-

parison of the behavior of these two structures during fertiliza-

tion is full of interest.

Except for certain accounts of Spirogyra, to be described in

the next paragraph, investigators agree that the chromatophores

or plastids of gametes never fuse in the sexually formed spore.

Plastids have not been found in the sperms of the gymnosperms,

pteridophytes, nor bryophytes. The sperms of some algz also

appear quite colorless at maturity but careful examinations have

shown in a number of forms a very small chromatophore in the

early stages of development. Other less highly differentiated

sperms are known to have chromatophores (e. g., Sphzeroplea,

Cutleria, Volvox). Both gametes in the isogamous types of

sexuality among the algae always have chromatophores or plas-

tids. These have been followed in detail through stages of fer-

tilization in Ectocarpus by Berthold ('8 1) and Oltmanns ('99),

and in Scytosiphon by Kuckuck ('98) where it is evident that

they do not unite and there is no reason for believing that differ-

ent conditions obtain among any of the lower forms such as

Ulothrix, Cladophora, Hydrodictyon, etc., although detailed

observations are greatly lacking on this point, chiefly because

the conjugating cells are generally very small.

Early accounts of the formation of the zygospore of Spirogyra

have reported some form of union of the chlorophyll bands of

the two gametes. The last work upon the subject, Chmielewski

(90a), reviews the results of previous investigators and gives a

detailed account of a species of Rynchonema (Spirogyra).

Chmielewski claims that the chromatophore of the gamete (male)

that passes over into the other cell (female) becomes disorgan-

ized as the zygospore develops. While the chlorophyll band of

the female cell retains much of its color, that from the male

becomes yellowish and breaks up into fragments which become

scattered in the zygospore and finally break down. This inter-

No. 460.] STUDIES ON PLANT CELL.— V. 239

esting account accompanied by clear figures gives an explanation

far more in keeping with what we know and might expect of the

behavior of chromatophores in resting spores. That the green

chromatophore may temporarily become much modified in color

and form is well known in some of the red and orange resting

spores of the Volvocacez and the zygospores of the desmids.

In some of these types the form and color of the chromatophores

become quite lost for the time being so that studies on their

behavior are very difficult. For these reasons it seems probable

that the accounts of the fusion of the chromatophore in the zygo-

spore of Spirogyra are incorrect. It is very interesting that the

gametes of Spirogyra should be so sharply differentiated that the

chromatophore of one should be reduced during conjugation in

a manner that resembles very closely the behavior of the chro-

matophore in highly differentiated sperms.

There is no evidence that the pigment spots, so generally

present in the motile gametes of lower forms, ever unite. They

have been followed into the zygospore and after the germination

of this cell and they remain entirely independent of one another

as would be expected from their close relationships to chromato-

phores.

The fate of the blepharoplast will now be considered. This

structure is especially interesting because of its close analogy to

the locomotor apparatus of the animal spermatozoön, which is

formed chiefly from one or more centrosomes generally with the

coóperation of archoplasm (idiosome, Nebenkern). It is also

claimed by a number of zoólogists that in some forms, at least,

the centrosomes of the first cleavage spindle are derived from

the spermatozoón.

All evidence indicates that the blepharoplast of the plant

sperm is left behind in the cytoplasm of the egg when the male

nucleus passes into the interior to unite with the female and

that centrospheres when present, in the first cleavage spindle,

are formed de novo. The fate of the blepharoplast is clearly

known in Cycas (Ikeno, '98b), Zamia (Webber, : 01) and Ginkgo

(Ikeno, :or). Soon after the large top-shaped sperm of these

forms enters the egg, the male nucleus slips out of the spiral

blepharoplast, that partially invests it, and, leaving it with

240 THE AMERICAN NATURALIST. (VoL. XXXIX.

other cytoplasm of the sperm at the end of the. egg, passes

quickly to the center to unite with the female nucleus. The

blepharoplast remains near the periphery of the egg and may be

recognized even after the gamete nuclei have united. It finally

breaks down and its substance becomes lost in the cytoplasm of

the egg. The most complete account of the history of the ble-

pharoplast in the fertilized egg is that of Webber (:01). We

should naturally expect the first cleavage spindle in the cycads

and Ginkgo to be developed as in the conifers. Ikeno (:O1)

described clearly an intranuclear spindle in Ginkgo. In the

conifers, as previously described, the first cleavage spindle is

intranuclear and the fibers are developed freely from a mesh

and form a broad poled spindle without centrospheres. So that

not only does the blepharoplast break down at a distance from

the egg nucleus but we have no reason to think that there is

any place for a centrosome in the history of the first cleavage

spindle in the gymnosperms.

We do not know clearly the fate of the blepharoplast in the

egg of any pteridophyte or bryophyte, although Shaw's (98a)

studies on Onoclea indicate that it breaks down in the cyto-

plasm. Our knowledge of the thallophytes is equally incom-

plete as regards the history of the blepharoplast in the egg.

But both Strasburger ('97a) and Farmer and Williams (98)

have agreed for Fucus that the two centrospheres at the poles

of the first cleavage spindle develop de novo and independently

of one another, and Williams (: 04b) holds the same view for the

centrosphere which appears at the side of the fertilized egg of

Dictyota. The sperms of the thallophytes are generally very

small cells and it may prove a difficult matter to follow their

blepharoplasts so that our opinions of events in these forms! are

likely to be largely inferential from our knowledge in higher

groups.

We can safely say that there is no evidence that the blepharo-

plast ever enters into the first cleavage spindle which is certainly

developed in the spermatophytes and probably in the pterido-

phytes without centrosomes or centrospheres.

somes or centrospheres are known for the first cl

in the thallophytes (Fucus and Dictyota),

Where centro-

eavage spindle

the observations indi-

No. 460.] STUDIES ON PLANT CELL.— V. 241

cate that such structures have not come from the blepharoplast.

Williams’ (:04b) recent work on Dictyota, while incomplete in

the series of stages illustrating the fusion of gamete nuclei (fer-

tilization), presents a very interesting comparison of the devel-

opment of the first -cleavage spindle in fertilized eggs with

parthenogenetic eggs. In the fertilized egg there is regularly

found a centrosphere which apparently divides into two that

separate until they lie at opposite poles of the mature spindle.

*In the parthenogenetic egg, on the contrary, the spindle is mul-

tipolar and develops very irregularly from a kinoplasmic mesh

which is intranuclear and there is no sign of centrospheres.

Williams believes that fertilization enables the fusion nucleus

to form de novo a centrosphere external to itself which is not

possible for the nucleus of a parthenogenetic egg.

It should be noted that these conclusions are all against the

view that the centrosome is a permanent organ of the cell and

that the blepharoplast holds any direct relation to centrosomes

when present in the first cleavage spindle and inferentially rather

strengthens the doubt that the blepharoplast is derived from a

centrosome, which point was discussed in our account of the

sperm in Section III. However, Ikeno (:04) in a paper which

arrived too late to be treated in Section III, is very positive that

blepharoplasts are centrosomes, presenting his evidence clearly,

but his explanation of the conditions under which blepharoplasts

are formed from the plasma membrane does not seem to me con-

clusive, especially in the light of Mottier's (: 04a) recent paper on

Chara, which also could not be treated in Section III (see Amer.

Nat., vol. 38, p. 576, 1904).

3. Asexual Cell Unions and Nuclear Fusions.

As stated earlier in the paper, the test of a sexual act must

lie with the history of the elements which unite, unless we

choose to treat sexuality as a purely physiological process and

disregard its relation to morphology in ontogeny and phylogeny.

This relation is so precise, 7. e., sexuality is so firmly established

as a fixed period in the life history of most organisms, that the

biologist generally thinks of the sexual process as a part of the

242 THE AMERICAN NATURALIST. (VoL. XXXIX.

life history, which must take place with as much regularity as

the normal development of any organ. As a matter of fact,

our knowledge of the structure of sexual elements and the events

of sexual phenomena is almost wholly morphological and for the

present at least it seems safer to treat and define sexuality from

a morphological standpoint.

Under asexual cell unions and nuclear fusions we shall include

a number of interesting phenomena which can be arranged in

three groups: (1) cell fusions which have apparently no sexual `

relations; (2) cell fusions which are substitutes for a normal

ancestral sexual process now suppressed; and (3) extraordinary

modifications of what may have been originally sexual processes

but which at present serve some peculiar and special function.

In the first group will be included the extensive union of

Swarm spores, or the amoeboid elements derived from such,

best illustrated in the development of plasmodia ; also such cell

fusions as are clearly for nutritive purposes, as is the union of

the sporophytic portion of the cystocarp of the red alge with

auxiliary cells and probably also the fusion of sporidia in the

smuts and the conjugation of yeast cells. The second group

embraces the interesting fusions of the nuclei in teleutospores

of the smuts and rusts and in the basidium with the previous

history of the paired (conjugate) nuclei in the mycelium, perhaps

also the nuclear fusions in the ascus, and such cell unions as

have been reported preliminary to the apogamous development

of the fern sporophyte, The third group includes the remarka-

polar nuclei and the triple fusion of these with the second sperm

nucleus, frequently called “double fertilization."

The well known union of the swarm spores of the Myxomy-

cetes as amceboid cells (myxamæbæ) to form the plasmodium is

one of the best illustrations of a fusion of protoplasm without

sexual significance. In this general union of hundreds and per-

haps thousands of small cells there are no nuclear fusions so far

as is known, but simply the merging of the cytoplasm to form a

large multinucleate unit. The whole phenomenon indicates a

coóperative process which is probably economical of nutritive

functions in the semiterrestrial conditions under which plas-

No. 460.] STUDIES ON PLANT CELL—V. 243

modia live. It is quite possible that the origin of sex may have

been involved with some of the same principles as those which

bring about the union of swarmers to form a plasmodium, but

the added features of nuclear fusion together with the history

of the sexually formed cells which become in higher groups the

starting point of a sporophyte generation places the sexual act

on a very much higher level of complexity.

There are some records of the union of several zoöspores or

gametes to form a zygospore instead of the usual conjugation in

pairs. The biciliate gametes of Acetabularia (De Bary and

Strasburger, '77) sometimes conjugate in threes and large

zygotes are figured with five pairs of cilia indicating that as

many gametes entered into their formation. The gametes of

Protosiphon, described by Rostafinski and Woronin (77) as in

the life cycle of Botrydium, are reported by them to unite at

times several together and four are so figured. Klebs ('96, p.

207) in his account of Protosiphon also noted the union of the

gametes in threes especially when in organic solutions. The

significance of these multiple fusions of swarm spores is not

clear for we know nothing of the nuclear history following the

union. There is in the habit, however, such a resemblance to

the extensive union of swarmers in.the Myxomycetes as to indi-

cate that primarily sexuality may have been concerned chiefly

with cytoplasmic fusions and associated very intimately with

nutritive processes. have recently observed several instances

of the conjugation of zoóspores of Saprolegnia when the ele-

ments united in pairs at the ciliated ends and along the sides

exactly as do motile gametes, and the fused cell bore four cilia.

The zoóspores of Saprolegnia are too far removed morphologi-

cally from the highly differentiated sexual organs of the group

to justify the explanation of such conjugation as a sexual act.

and we must think of it as due to some peculiarities of nutritive

conditions.

Another class of very interesting cell fusions, associated with

nutritive functions, is presented in the union of the sporophytic

fertile filaments (oóblastema filaments) in the cystocarp of the

Rhodophycez with auxiliary cells. This phenomenon which

was regarded by Schmitz and his followers as sexual in charac-

244 THE AMERICAN NATURALIST. (VoL. XXXIX.

ter, is considered by Oltmanns ('98b) to have nutritive relations

alone. Oltmanns studied the fusion with auxiliary cells in sev-

eral genera, but especially for Callithamnion and Dudresnaya,

and is satisfied that the cell unions concern only the cytoplasm.

Fertilization takes place with the fusion of gamete nuclei in

the carpogonia and these cells develop the sporophyte genera-

tions. The fusion of fertilized carpogonia or filaments derived

from them with auxiliary cells, is a feature of a sort of semipara-

sitic relation that the sporophyte holds to the gametophyte by

which it is nourished in part through organic connections with

the gametophyte. The nuclei of the sporophytic structures

remain quite apart from those of the auxiliary cells so that the

union is purely cytoplasmic. This theory of Oltmanns has

received strong support through the detailed nuclear studies of

Wolfe (: 04) on fertilization and the development of the cysto-

carp of Nemalion who finds cytological evidence of the sporo-

phytic character of the cystocarp. These papers of Oltmanns

and Wolfe have been discussed by myself in the Bot. Gaz., vol.

27, P. 314, 1899, and vol. 39, p. 64, 1905.

Writers have at times attached sexual significance to the con-

spicuous fusions between sporidia of certain of the Ustilaginales

(e. g., Tilletia). But there seems at present no reason to regard

this phenomenon as different from the cytoplasmic connections

frequently established between cells of hyphz which are ulti-

mately associated in a common mycelium where the whole

forms a close unit with respect to common nutritive relations.

Such protoplasmic connections were treated in the first part of

this section. Harper (99a) studied the union of conidia and

cells of the promycelium in Ustilago and concluded that the

fusions involve the cytoplasm alone, there being no nuclear

changes. However, Federley (:03-: O4; review in Bot. Zeit;

vol. 62, p. 171, 1904) has observed the migration of a nucleus

from one conidium to another in Ustilago tragopogonis pratensis

(Pers.), and a fusion within the latter. This nuclear fusion was

not found in some other forms of Ustilago which behaved as

Harper has described. There is nothing in the morphology of

the conidia to indicate that they are sexual cells and from what

we know of the life history of Basidiomycetes we should look

No. 460.] STUDIES ON PLANT CELL.— V. 245

for sexual processes at other periods more closely associated

with the development of teleutospores or basidia.

The conjugation of yeast cells has many points of similarity

to the fusion of conidia in the Ustilaginales. This phenomenon

has been discovered in an organism obtained from commercial

ginger by Barker (:01), which he calls Zygosaccharomyces, and

in three species of Schizosaccharomyces by Guilliermond (: 03).

The conjugation in all forms immediately precedes spore forma-

tion and involves a nuclear fusion as well as that of the cyto-

plasm. The conjugation is followed by division of the fusion

nucleus and spore formation in the united cells. The con-

jugating cells are sisters in the species of Schizosaccharomyces

but apparently may not be closely related in Barker's form,

Zygosaccharomyces. Both investigators regard the conjugation

as a sexual act, and Guilliermond considers the fusion cell to be

an ascus with the value of a zygospore. These conclusions do

not seem to the writer convincing. Spore formation in the

yeasts has not been shown to present any of the peculiarities of

nuclear division and free cell formation as described by Harper

for the ascus, and until such are established it is hardly safe to

conclude that the yeasts are Ascomycetes: Whether or not the

conjugation is a sexual process becomes a question of phylogeny

and we know too little of the history and relationships of the

yeasts to assert that the conjugating cells are morphologically

gametes. Again, the view that yeasts are derived from conidia

or mycelia of higher fungi which have continued a simple

growth by budding in peculiar and favorable media is rather

against any view that we are dealing here with a simple or

primitive sexual act. There are very striking resemblances to

the fusions of conidia in the Ustilaginales, which were described

in the previous paragraph and do not appear to be sexual proc-

esses. It is unsafe to assume sexuality because the conjuga-

tion precedes spore formation, because in most yeasts spore

formation takes place regularly without conjugation. Is it not

rather another illustration of cell and nuclear fusions related to

nutritive processes alone ?

Some of the most interesting nuclear fusions, apparently

associated with the apogamous development of a sporophyte are

246 THE AMERICAN NATURALIST. . [Vor. XXXIX.

the unions of the pairs of nuclei which enter the cells of the

developing teleutospores of the Uredinales and Ustilaginales

and the basidium of higher Basidiomycetes. It has been estab-

lished through the studies of a number of investigators (chiefly

Rosen, '93; Dangeard and Sapin-Trouffy, '93 ; Dangeard '93,

'04—95a, c; Poirault and Raciborski, '95 ; Sapin-Trouffy, '96;

Maire, :00 a, b, c, :02; Holden and Harper, :03) that the

ecidiospores and the mycelium derived from them and pre-

ceding the development of the uredospores and teleutospores

contain pairs of nuclei which divide in such a manner (conjugate

division) that the nuclei of the pair are derived through two

unbroken lines of succession fora long vegetative period and

always maintain complete independence of one another. Every

young teleutospore and basidium contains such a pair of nuclei

which shortly fuse so that the mature structure is uninucleate.

Dangeard and Sapin-Trouffy have from the first regarded the

nuclear fusion within the teleutospore, whether of rust or smut,

as a sexual act and the ripe teleutospore a fertilized egg, regard-

less of the fact that its morphology was not that of any known

sexual organs. Dangeard ('94—95 c; :00) likewise considered

the nuclear fusions in the basidium as sexual. Raciborski (96)

suggested that the series of conjugate mitoses leading to the

nuclear fusions in the teleutospore represented a vegetative

phase intercalated between the beginning of a sexual act and its

finish in the teleutospore. His explanation, in the light of the

recent paper of Blackman (:04a), was nearest the truth. Maire

(:02) presents the most extensive account of the nuclear struc-

ture in the higher Basidiomycetes previous to and during the

formation of the basidia. He held that the fusion of the paired

nuclei (synkaryon) in the basidium was not the whole act of

fertilization which must begin with the formation of the paired

nuclei. Maire (: 02, p. 189) gave some suggestions as to how

and where the paired nuclei arose but neither he nor any of the

authors mentioned above knew clearly their origin.

Blackman (: 04a) has made the most important contribution to

the subject of fertilization and alternation of generation in the

Uredinales, showing clearly that the paired nuclei appear in the

life history of Phragmidium violaceum and Gymnosporangium

No. 460.] STUDIES ON PLANT CELL.— V. 247

clavarigforme just before the development of the zcidium.

They arise in Phragmidium by the migration of a nucleus from

an adjacent cell into an element (the fertile cell) which represents

a female sexual organ. The morphology of the female organ is

not clear but there are suggestions of a structure similar to the

procarps of the Rhodophycez and Laboulbeniales. The fertile

cell, after receiving its second nucleus, develops a chain of

zecidiospores, the two nuclei becoming so closely associated in

the paired condition that they divide simultaneously (conjugate

mitosis) from now on until the teleutospores are formed. Thus

the cells of all mycelium beginning with the zecidiospore con-

tain paired nuclei up to the development of the teleutospores,

including of course the uredospores when present. This period

of the life history may be considered as representing a sporophyte

generation, especially since the total of chromatin in the pair of

nuclei is double the amount when the nuclei are solitary. The

sporophyte phase ends with the fusion of the pair of nuclei in

each cell of the teleutospores and in the reduction phenomena

that take place with the germination of the teleutospore, includ-

ing the formation of the promycelium. The sporidia developed :

by the promycelium are uninucleate and the cells of the mycelium

derived from them are uninucleate up to the production of the

zecidium. This constitutes the gametophyte phase of the life

history. The spermogonia by their morphology seem to be

male organs, now functionless.

In such of the Uredinales as have no zecidium, as also in the

higher Basidiomycetes and the Ustilaginales, it is probable that

both sexual organs are suppressed since no trace of such struc-

tures has been found. However, we may expect to discover

periods in all of these forms when paired nuclei come into the

life history and after a series of conjugate divisions fuse in the

teleutospore or basidium. Such pairs of nuclei, as stated before,

are known in the Ustilaginales (Dangeard, '93) and in a number

of forms of the Uredinales and the nuclear fusions have been

followed in the teleutospore. Holden and Harper (:03) have

given an especially clear account of the paired nuclei in the

mycelium and uredospores of Coleosporium together with their

fusion in the teleutospore. Maire (:02) describes the paired

248 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

nuclei (synkaryons) and their fusion in the basidium in a large

number of Hymenomycetes and Gasteromycetes.

Evidence is thus accumulating that the cells in the mycelium

of higher Basidiomycetes (Hymenomycetes and Gasteromycetes)

are binucleate for extended periods previous to the formation of

basidia where nuclear fusions always take place. Binucleate cells

in the higher Basidiomycetes were first reported by Maire (: 00a ;

: oob), in the tissue preliminary to spore formation. He also con-

firmed Dangeard ('94—'95c) in his view that only two nuclei unite

in the basidium contrary to accounts of Rosen ('93) and Wager

(99, p. 586) which described a succession of fusions involving

sometimes as many as six or:eight nuclei. Harper (:02) has

given for Hypochnus one of the most complete accounts of the

behavior of paired nuclei previous to and during the development

of the basidium. The cells of the mycelium of this simple

Hymenomycete were found to be binucleate as far back as they

were studied which included all of the conspicuous vegetative

structure. Only a single pair of nuclei enters the basidium and

fuses. Harper's results are then in agreement with the extended

observations of Maire (:02) as are also the detailed studies of

Ruhland (:01) on a number of forms and Bambeke (:03).

Taken together they seem to show clearly that the mycelium,

for long periods preliminary to the formation of basidia, contains

paired nuclei and that the basidia receive each a single pair,

which nuclei fuse. There is thus an exact correspondence

between the life histories of the Ustilaginales, Uredinales, and

higher Basidiomycetes with respect to the period of paired

nuclei and their fusion in the teleutospore or basidium.

Dangeard called the fusion in the basidium a sexual act and the

structure an oóspore regardless of the morphological difficulties

of such a conception. Maire (:02, p. 202) states that the origin

of the paired nuclei is the only phenomenon strictly comparable

to fertilization and Blackman's studies support this view. Ruh-

land (: o1) regards the conditions as a deviation from the normal

type of sexuality calling it “intracellular karyogamy." The

origin of the paired nuclei is not known for any higher Basidi-

omycete and the discovery of this period and determination of

the events leading to the change from uninucleate mycelium to

No. 460.] STUDIES. ON PLANT CELL. —VF. 249

binucleate is one of the most interesting problems in this field of

botany. This is the point where we should expect to find the

remains of sexual organs, if any are present in the higher

Basidiomycetes, but it is not likely that they will be found. It

seems more probable that the mycelium with the paired nuclei

(perhaps sporophytic in character) arises apogamously with a

complete suppression of the sexual organs in agreement with such

of the Uredinales as have no zecidium and the Ustilaginales.

Blackman's explanation of the history of the paired nuclei in

Phragmidium is full of interest. As stated before, he regards

the fertile cell which develops a chain of zcidiospores, “as a

female reproductive cell which undergoes a process of fertiliza-

tion" by a union with an adjacent cell of the mycelium and its

reception therefrom of a nucleus. The mycelium then which

arises with the zcidiospore is sporophytic in character and so

remains until the fusion of the pairs of nuclei in the teleuto-

spores. The male organs of the rusts are the spermogonia and

the male gametes the spermatia which are of course now func-

tionless so that the “process of fertilization" is through the

introduction into the female cell of a nucleus which is not phy-

logenetically a male sexual element. Blackman’s (:04a, pp.

349—353; :04 b) conception of the process as an act of ferti-

lization involves some principles which will be briefly outlined.

Blackman believes for Phragmidium “ that the primitive normal

process of fertilization by means of spermatia has been replaced

by fertilization of the female cell through the nucleus of an

ordinary vegetative cell " and regards the process as very similar

to the phenomenon reported in the apogamous development of

ferns by Farmer, Moore, and Digby (:03), which will be consid-

ered presently. Blackman points out that normal processes of

fertilization such as we have included under the head of ‘sexual

cell unions and nuclear fusions" do not involve in many forms

(probably all types with a sporophyte generation) an immediate

union of the chromatin of the sexual nuclei which is known to

remain distinct during the first cleavage mitosis in a number of

types (e. g., Pinus and some other gymnosperms). So there is

nothing in the delayed fusion of the paired nuclei up to the

teleutospore that is seriously against his explanation of the “ fer-

250 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

tilization" of the female cell of the Uredinales. Indeed, we

may expect to find that the actual fusion of paternal and mater-

nal chromatin does not take place in the higher plants until the

end of the sporophyte generation in the spore mother cell, as

zoólogists have concluded that such union occurs just previous to

gametogenesis in animals. But is Blackman justified in regard-

ing the phenomenon substituted for the activities of ancestral

sexual organs in Phragmidium, now functionless, as a sexual act

and is it desirable to apply the term fertilization to the phe-

nomenon ?

Blackman (:04b, p. 153) speaks of the introduction of a

nucleus into the fertile cell of the Uredinales and the phenome-

non in the apogamous development of the fern after the account

of Farmer, Moore, and Digby (:03) as “ reduced forms of ferti-

lization.” It may be questioned whether the use of the term

fertilization is fully justified by the events under discussion. We

are all likely to agree with these authors that the physiological

aspects of the phenomena in the cases under consideration are

similar to sexual acts. But, by the writer, the act of fertiliza-

tion is always considered in phylogenetic relations and strictly

limited to the union of sexually differentiated cells, which are

defined by their morphology through principles of homology.

Whenever one or both of the gametes are suppressed in a life

history and a succeeding generation develops of the sort that

normally follows a sexual act, then such a development is apoga-

mous and the phenomena always introduce features which are

foreign to the processes of normal fertilization and the funda-

mental principles of sexuality.

Perhaps the most important characteristic of sexuality from

an evolutionary standpoint is the fusion of gametes of unrelated

parentage, for in the mingling of diverse protoplasm lie two

factors: (1) a physiological stimulus to development, and (2) an

increased probability of inherited variation which in new combi-

nations will appear to the advantage of the species. Blackman's

“reduced forms of fertilization" which I should prefer to con-

sider apart from normal fertilization as examples of apogamy,

and have so classed in this treatment, do satisfy the physiologi-

cal requirements of a sexual act in that a form of nüclear fusion

No. 460.] STUDIES ON PLANT CELL.— V. 251

is substituted for the union of gamete nuclei but the phylogenetic

and evolutionary aspects of sexuality are disregarded. Also, the

nuclei that fuse are sometimes very closely related, which is a

condition generally avoided in sexual processes except where

peculiarities of habit make close inbreeding necessary. It is

true that large groups, such as the Basidiomycetes, perhaps

certain regions of the Ascomycetes, some Phycomycetes, and

some forms of the higher plants and algae seem to have given up

normal sexual processes but there is much evidence that in many

cases this loss of sexuality is associated with a certain degree of

segregation and with peculiarities of life conditions apart from

the normal activities of all organisms or quite different from the

ancestral stock. The groups are likely to be distinguished by

highly specialized life habits of a sort that make it impossible

for inherited sexual organs to function, either through mechan-

ical difficulties or because one or both degenerate. It seems to

me much clearer to regard all illustrations of Blackman's

“reduced forms of fertilization" under the general term of

apogamy even though it may be clear that they are physio-

logical substitutes for sexual acts and to reserve the term fertil-

ization for the union of gametes which can always be clearly

identified through morphology in ontogeny and phylogeny. The

success of a group even though ancestral sexual processes may

be suppressed does not enter into a problem which is at bottom

a morphological one. Success is relative and we really have no

means of estimating its degree save by actual experiment. It is

not likely that any biologist would claim that sexual degenera-

tion is advantageous to any species although the organic world

is full of forms which have dispensed with sexuality and still

hold their places. These are the reasons why I have grouped

cell unions and nuclear fusions as sexual and asexual on a mor-

phological basis founded on phylogenetic principles and why in

Section V, we shall devote some attention to the substitutes for

sexuality under the head of apogamy.

The Ascomycetes present a phenomenon of nuclear fusion

within the ascus which may properly be considered at this time

since there is a certain resemblance to the nuclear fusions in

the teleutospore and basidium. Dangeard ('94—95b) gave the

252 THE AMERICAN NATURALIST. [Vor. XXXIX.

first account of this phenomenon describing it for several forms.

The mother cell of an ascus sometimes terminates a hypha but

more commonly is situated a little back from the end at a point

where the hypha bends abruptly like a knee. The mother cell

contains two nuclei, closely related to each other, that unite,

after which the fusion nucleus divides to form the ascospores.

Dangeard considered this fusion to be a sexual act and the

product an oóspore which germinates immediately to form the

ascus. He regards the ascus as a sporangium, and equivalent

to the promycelium which he calls a conidiophore. Dangeard

is not willing to accept any of the evidence that the ascocarp

ever results from a sexual act or that sexual organs either func-

tional or abortive are present at any stage in the life history of

Ascomycetes. Sexuality, according to him, is reduced to the

fusion within the ascus alone. He (Dangeard, '96—97a, b;

: 00) discredits the work of Harper on Sphzrotheca, Erysiphe,

and Pyronema and the older accounts of De Bary and his pupils

on sexual organs of the Ascomycetes. A series of short papers

in Le Botaniste (: 03, Fas. 1) presents Dangeard’s last attack on

the work of Harper and a reaffirmation of his peculiar views.

Harper's description of sexual processes in Spheerotheca ('95 ;

'96) Erysiphe ('96), and Pyronema (:00b) are so convincing

that, together with our knowledge of sexual organs in the

lichens, Laboulbeniales, and Gymnoascales, we must accept the

old view of De Bary that the ascocarp represents a development

(probably sporophytic) from a sexual phase even though it may

be established that there is much apogamy in the Ascomycetes.

Harper gives the clearest account of the nuclear fusion in the

ascus of any author without, however, committing himself to

speculations on its significance. The subject is well sum-

—_— a on Pyronema (:oob, pp. 363, 394). He

‚ Fyronema, and some other forms that the

ascus is always developed from a penultimate cell of a hypha

which bends sharply so that this cell appears to lie at the tip.

There are two nuclei at the end of the ascogenous hypha and

these divide simultaneously in a very characteristic manner so

that the young: ascus receives two of the resultant four nuclei,

but each is derived from a different one of the original pair and

No. 460.] STUDIES ON PLANT CELL.—V. 253

consequently they are not sisters. The two nuclei in the ascus

then fuse. The origin of the original pair is not known.

No satisfactory explanation of this fusion in the ascus has

been advanced. The conditions in the Ascomycetes are not the

same as in the Basidiomycetes. There is no series of paired

nuclei in the ascogenous hyphae and no evidence of a delayed

fusion of gamete nuclei following a sexual act nor of nuclear

fusions associated with the apogamous development of a sporo-

phyte generation. On the contrary, a sexual act with the

fusion of gamete nuclei has been clearly established in some

forms preliminary to the development of the ascocarp and the

nuclear union in the ascus is plainly a supplementary phenom-

enon. Wager and Harper point out analogies to the account of

Chmielewski (’90b) for Spirogyra, considered in a previous part

of this section, which described a double nuclear fusion in the

zygospore. Thus the primary, sexually formed nucleus of the

zygospore is reported to divide into four secondary nuclei, two

of which break down while the remaining two unite forming the

second and final fusion nucleus of the spore. It is hard to see

how these second nuclear fusions can be sexual and Groom ('98)

is perhaps correct in considering them superimposed on the sex-

ual act, but their physiological significance is not clear.

Some recent papers support in general Harper’s investigations

on the ascus. Guilliermond (: 04a; :04b) describes the devel-

opment of the ascus and ascospores in a number of forms. In

an unnamed species of Peziza he found, however, that the ascus

developed from the terminal cell of the ascogenous hypha which

received two nuclei (that fuse) of the four that are found at the

tip. Maire (:03a; :03b) has reported a similar history for

Galactinia succosa. Both Maire and Guilliermond note the

resemblance of these conditions to the nuclear associations in

the young basidium and Maire does not hesitate to consider the

two nuclei in the tip of the ascogenous hypha as much reduced

synkaryons, (paired nuclei) appearing for a very short period

just previous to the nuclear fusions in the ascus. Maire fol-

lows Dangeard in denying the sexual processes described by

Harper in the Ascomycetes and would allign the events in the

ascus with those in the basidium. Guilliermond agrees with

254 THE AMERICAN NATURALIST. (Vot. XXXIX.

Harper that the number of chromosomes presented in the

mitoses within the ascus is large (8, 12, 16, in various species)

as against Dangeard and Maire who have claimed that the

number is uniformly 4. Guilliermond's account of spore forma-

tion in the ascus supports that of Harper (described in Section

II) in all essentials and gives especial attention to the structure

of the epiplasm and its inclusions.

In summary : the significance of the nuclear fusions in the

ascus seems very much of a mystery. If they could be associ-

ated with an apogamous development of the ascocarp we should

have conditions analogous to those in the Basidiomycetes but

following a sexual act as it does in Sphzerotheca, Erysiphe, and

Pyronema we find a phenomenon whose raison a’ étre is not

apparent. However, we do not know the history of the nuclei

preceding the group of four at the end of the ascogenous hypha

and perhaps it may be discovered that events at this period are

concerned with nuclear reduction at the end of a sporophyte

generation.

One of the most interesting announcements of recent months

is that in a preliminary note of Farmer, Moore, and Digby (:03)

on the nuclear history preceding the apogamous development of

a species of Nephrodium. They found that the cells of the

prothallus at the point where the sporophyte arose became

binucleate by the migration of nuclei from neighboring cells.

The two nuclei might remain separate for some time or fuse at

once, The authors speak of the whole process “as a kind of

irregular fertilization" and Blackman considers it analogous to

the entrance of the nucleus into the fertile cell of Phragmidium

and the establishment of the paired nuclei in the Uredinales.

As we discussed the phenomenon in that connection I consid-

ered the use of the term fertilization unfortunate since it

included processes which however similar physiologically held no

relation morphologically and phylogenetically to normal sexual

processes. As stated then, it seems to me much clearer to

regard all such apogamous phenomena apart from sexual proc-

esses, pointing out as far as possible physiological resemblances

but recognizing the wide gap in morphology established by the

past evolutionary history of the plant. The interest in the phe-

No. 460.] STUDIES ON PLANT CELL.—V. 255

nomena does not become less by this treatment which certainly

avoids much confusion of expression.

There is left for consideration one other group of nuclear

fusions which may have sexual significance although such is

not obvious, namely the fusions of polar nuclei in the embryo

sac of angiosperms and the triple unions of the above with a

second sperm nucleus which is often called “double fertiliza-

tion." Several excellent reviews of this subject have appeared,

notably by Strasburger (:00b), Sargant (:00), Coulter and

Chamberlain (:03), Mottier (:04a, b), and Guérin (:04). The

explanation of this phenomenon is likely to rest finally upon

morphological analysis but at present we are uncertain of the

homologies of the polar nuclei and the part they play in the

evolutionary history of the endosperm. The most striking

theory of the endosperm was proposed by LeMonnier (787) who

suggested that the fusion of the polar nuclei gave origin to a

second embryo modified to nourish the normal embryo. One

of the polar nuclei is always closely related to the egg nucleus

so that in the triple fusions (the sperm with two polar nuclei)

we have conditions very close to normal fertilization, the dis-

cordant element being not the sperm nucleus but the antipodal

polar nucleus. The triple fusions would seem at first thought

to be rather favorable to LeMonnier's theory although it is plain

that with such a diverse mixture of chromatin from three nuclei

the resultant structure can scarcely be called a sporophyte

embryo from the very grotesqueness of its make-up. Miss

Sargant considers the fusion of the second sperm with the

micropylar nucleus as sexual in character but so complicated

by the introduction of the antipodal polar nucleus that the

result is a bizarre structure not strictly comparable to a normal

embryo. In the final solution of this problem we must know

whether in phylogeny the sperm and micropylar polar nucleus

fused first and the antipodal entered into the process later or

whether the polar nuclei began the habit and the second sperm

nucleus was drawn afterwards into the activities. Should the

first possibility be established the sexual nature of the process

would seem clear while in the second the events would be of

the nature of asexual nuclear fusions. While we know very little

256 THE AMERICAN NATURALIST. (Vor. XXXIX.

of the origin and evolution of the endosperm in angiosperms

there is some evidence in favor of the second possibility.

Strasburger (:00b) holds that the double and triple nuclear

fusions in the embryo sac are not true sexual acts even though

they may involve an important principle of fertilization, namely,

a stimulus to growth. According to him, sexual processes pre-

sent two distinct features which he designates as “ generative

fertilization" and * vegetative fertilization." Generative fertili-

zation deals with the mingling of ancestral hereditary substances

in the nuclei and establishes the basis for such characters as

hold the species true to its past or introduce new qualities as

variations into the germ plasm. Vegetative fertilization brings

to the fusion nucleus simply a stimulus to growth such as may

be given to unfertilized eggs by changes in their physical and

chemical environment. We might apply this classification to

many of the examples of asexual nuclear fusions which we have

discussed, as in the apogamous development of the fern and the

origin of the paired nuclei in the rusts, and they have the ele-

ments of vegetative fertilization in Strasburger’s sense. But

such distinctions are very subtle and it seems rather doubtful

whether they add much to the clearness of our conceptions.

The growth stimulus of « vegetative fertilization” is always

an accompaniment of “generative fertilization” and would be

expected of any cell unions or nuclear fusions. The pecul-

iarities of sex lie in the phylogenetic features of the phenomena,

i. e„ in the union of differentiated gametes with their long evolu-

tionary history and not in the mere fusion of any nucler at any

time.

From this point of view the double fusions of polar nuclei or

the triple fusions, when a sperm nucleus becomes involved in

the phenomenon, are of very doubtful sexual nature since no

phylogenetic connections have been established with the normal

sexual processes of the spermatophytes.

irregularities in the process of endosper

plicate the discussion and make it ve

ships.

Indeed, there are many

m formation which com-

ry difficult to trace relation-

Thus nuclear fusions are described in the late stages of

endosperm formation when several of the free nuclei become

included in the same cell area by the formation of the cell walls

No. 460.] STUDIES ON PLANT CELL.— V. 257

(Corydalis, Strasburger, '80; Tischler, :00; Canna, Humphrey,

'96). Such nuclei are known to unite two or more and some-

times several together within the cells, forming fusion nuclei

with a large and variable number of chromosomes. In Peperomia

and Gunnera the endosperm nucleus results from the fusion of

several free nuclei and a number of instances are recorded in

which no fusion of the polar nuclei takes place, but the endo-

sperm is derived from the division of one or both. Such irregu-

larities, which will probably be greatly increased in number as

investigations proceed, indicate that the double and triple

fusions preceding the differentiation of the endosperm nucleus

are not of phylogenetic importance but are more likely to be

special developments in relation to peculiarities of seed forma-

tion among the angiosperms rather than of a sexual nature.

However, the triple fusions, when a sperm enters into the

composition of the endosperm nucleus, seem to furnish a

cytological explanation of the phenomenon of xenia and thus

come into very close physiological relations to sexual processes.

In xenia we find the effects of hybridization expressed immedi-

ately outside of the embryo in the endosperm of the seeds. If

paternal chromatin has entered into the composition of the endo-

sperm nucleus or should the sperm nucleus by itself give rise to

.a series of endosperm nuclei the appearance of paternal char-

acters would: be expected. This explanation of xenia was worked

out independently by DeVries, Correns, and Webber, the last

author having published a particularly clear'and full account of

the phenomenon (Webber, : 00). Even though the relation of

xenia to hybridization is apparent, it is nevertheless clear that

we are dealing with an exceptional process only possible because

of the unusual conditions within the embryo sac which allow a

second sperm nucleus to enter into the activities of seed forma-

tion and it is certainly not established that these activities have

any phylogenetic relations to past sexual processes.

Some interesting studies of Nemec (:02-:03; :04) upon

asexual nuclear fusions may open the way for explanations of

some of the examples which we have considered as asexual in

the latter portion of this paper. Nemec found that mitosis in

the root tip of Pisum sativum could be checked during anaphase

258 THE AMERICAN NATURALIST. | (Vor. XXXIX.

by treating the material with chloral hydrate so that no walls

were formed between the daughter nuclei, which remained in

the common mother cell and presently fused with one another.

The fusion nucleus presented a double number of chromosomes

(twice that of the normal sporophyte) in succeeding mitoses

which became reduced in a few hours so that later divisions

showed the number characteristic of the sporophyte. Nemec

regards nuclear fusions and reduction phenomena as self regulat-

ing processes which follow the vital cell fusions characteristic of

fertilization. The latter (cell fusions) are then the essential

phenomena of sex and nuclear activities follow automatically.

Reduction phenomena are atavistic in character. Nemec con-

siders these results in serious conflict with Strasburger's (94)

theory of the periodic reduction of the chromosomes, believing

that the number of chromosomes is not so likely to give the

characters of the respective sporophyte and gametophyte gener-

ations as other factors.

Nemec's contribution is chiefly of interest to us in the present

connection as showing that nuclear fusions may result from dis-

turbances of the normal environment very far removed from the

conditions that produce sexual cells. And this emphasizes our

contention that sexual processes must be judged through phylo-

genetic analysis and not by physiological resemblances. Thus

the nuclear fusions in the ascus, in the basidium, preceding apog-

amous development of the fern, and perhaps the union of polar

nuclei in the embryo sac may be involved with special physio-

logical conditions although they resemble outwardly sexual

processes and are sometimes a substitute for these. But never-

theless they are asexual nuclear fusions lacking that funda-

mental character of sexuality, the result of sexual evolution,

namely, a fixed position in a life cycle established by phylogeny

and cupro by the classic phrase * ontogeny repeats phylog-

eny.” They are departures from the normal life history either

apogamous in character or concerned with some other peculiarity -

of the plants' existence.

No. 460.] STUDIES ON PLANT CELL. —FV. 259

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264 THE AMERICAN NATURALIST. [Vor. XXXIX.

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Journ. d. Bot., vol. t, p. 140.

MAIRE.

:00a. Sur la cytologie des Hymenomycétes. Compt. Rendus, vol. 131,

p.321.

MAIRE.

:00b. Sur la cytologie des Gasteromycétes. Compt. Rendus, vol. 131,

p. 1246.

MAIRE.

:00c. L'évolution nucléaire chez les Endophyllum. Journ. d. Bot.,

vol. 14, p. 8o

MAIRE.

:02. Recherches cytologiques et taxonomiques sur les Basidiomycétes.

. 5oc. Mycol. d. France, vol. 18.

MAIRE.

‘OSa. Recherches cytologiques sur le Galactinia succosa. Compt.

Rendus de l'Acad. Sci. Paris, Nov. 9, 1903.

MAIRE.

:03b. La formation des asques chez les Pezizes et l'évolution nucléaire

des Ascomycétes. Compt. Rendus d. Sean. d. 1. Soc. Biol., vol.

55, p. 1401.

MEYER.

'96. Die Plasmaverbindungen und die Membranen von Volvor globator,

aureus und ZerZius mit Rucksicht auf die tierischen Zellen. Bot.

Zeit., vol. 54, p. 187.

MEYER.

:02. Die Plasmaverbindungen und die Fusionen der Pilze der Flori-

deenreihe. Bot. Zeit., vol. 60, p. 139.

MICHNIEWICZ.

Ueber Plasmodesmen in den Kotyledonen von Lupinus-Arten und

ihre Beziehung zum interzellularen Plasma. Oester. bot. Zeitsch.,

vol. 54, p. 165.

MIEHE.

:01. Ueber die Wanderungen des pflanzlichen Zellkernes. Flora, vol.

88, p. 105.

MIYAKE.

:01. The Fertilization of Pythium deBaryanum. Annals of Bot., vol.

15, p. 653.

No. 460.] STUDIES ON PLANT CELL.—V. 265

MIYAKE.

:03a. On the Development of the Sexual Organs in Picea excelsa.

Annals of Bot., vol. 17, p. 351.

MIYAK

a | Contthation to the Fertilization and Embryogeny of Abies bal-

samea. Beiheft z. Bot. Centralbl., vol. 14, p. 134.

MOENKHAUS.

The Development of the Hybrids between Fundulus heteroclitus

and Menedia notata with especial Reference to the Behavior of

the Maternal and Paternal Chromosomes. Amer. Journ. of Anat.,

3, D. 49.

MONTGOMERY.

:01. A Study of the Germ Cells of Metazoa. Trans. Amer. Phil. Soc.,

vol. 20, p. 154.

MOTTIER.

'8. Ueber das Verhalten der Kerne bei der Entwickelung des Embryo-

sacks und die Vorgänge bei der Befruchtung. Jahrb. f. wiss. Bot.,

vol. 31, p. 125.

MOTTIER.

:04a. The Development of the Spermatozoid in Chara. Annals of Bot.,

vol. 18, p. 245.

MOTTIER.

:04b. Fecundation in Plants. Carnegie Inst. Washington, 1904.

MÜLLER.

'08.99. Kammern und Poren in der Zellwand der Bacillariaceen. I,

II. Ber. deutsch. bot. Gesellsch., vol. 16, p. 386; vol. 17, p. 432.

MURRILL.

:00. The Development of the Archegonium and F ertilization in the

Hemlock Spruce nae Canadensis Carr.) Annals of Bot., vol.

14, p. 583.

NEMEC.

:02-:03. Ueber dob dis iid Kernverschmeltzungen. I, II, III.

Sitz. kön. bóhm. Gesellsch. Wiss., 1902-03.

NEMEC.

:04. Ueber die Einwirkung des Chloralhydrats auf die Kern- und

Jahrb. f. wiss. Bot., vol. 39, p- 645.

OLTMANN

'95. teer die Entwickelung der Sexualorgane bei Vaucheria. Flora,

vol. 8o, p. 388

OLTMANNS.

98a. Die Entwickelung der Sexualorgane bei Coleochete pulvinata.

Flora, vol. 85, p. I.

OLTMANNS.

'98b. Zur Entwickelungsgeschichte der Florideen. Bot. Zeit., vol. 56,

p. 99-

266 THE AMERICAN NATURALIST. (Vor. XXXIX.

OLTMANNS.

'99. Ueber der Sexualität der Ectocarpeen. Flora, vol. 86, p. 86.

OSTERHOUT.

: 00. Befruchtung bei Batrachospermum. Flora, vol. 87, p. 109.

PorRAULT and RACIBORSKI.

'95. Surle noyau des Urédinées. Journ. d. Bot., vol. 9, p. 318.

RACIBORSKI.

'96. Ueber den Einfluss äusserer Bedingungen auf die Wachstumsweise

des Basidiobolus ranarum. Flora, vol. 82, p. 107.

REINHARDT. :

Das Wachstum der Pilzhyphen. Jahrb. f. wiss. Bot., vol. 23,

P- 47

ROBERTSON.

:04. Studies in the Morphology of Torreya californica Torrey. II.

The Sexual Organs and Fertilization. New Phytologist, vol. 3,

p. 205.

Rosen.

'98. Studien über die Kerne und die Membranbildung bei Myxomyceten

und Pilzen. Cohn’s Beitr. z. Biol. d. Pflan., vol. 6, p. 237.

ROSTAFINSKI und WORONIN.

77. Ueber Botrydium granulatum. Bot. Zeit., vol. 35, p. 649.

RUHLAND.

:01. Zur Kenntniss der intracellularen Karyogamie bei den Basidio-

myceten. Bot. Zeit., vol. 59, p. 187

Russow,

'83. Ueber den Zusammenhang der Protoplasmakórper benachbarter

Zellen. Sitz. dorpater naturf, Gesellsch., 1883.

SAPPIN-TROUFFY.

'96. Recherches histologiques sur la famille des Urédinées. Le Botan-

iste, vol. 5, p. 59

SARGANT. ;

-:00. Recent Work on the Results of F ertilization i

Annals of Bot., vol. 14, p. 689.

SCHMIDLE.

'99. Einiges über die Befruchtung,

n Angiosperms.

Keimung und Haarinsertion von

Batrachospermum. Bot. Zeit., vol. 57, p. 125.

SCHRAMMEN.

:02. Ueber die Einwirkung von Temperaturen auf die Zellen des Vege-

tationspunktes des Sprosses von Vicia foba. Verhand. d. natur-

hist. Vereins d. preuss. Rheinlande, vol. 59.

SCHUTT.

'99. Centrifugales Dickenwachstum der

Membran und extramembran-

oses Plasma. :

ahrb. f. wiss. Bot., vol. 33, P- 594.

No. 460.] STUDIES ON PLANT CELL. —V. 267

SCHUTT.

:00a. Die Erklärung des centrifugalen Dickenwachstum der Membran.

Bot. Zeit., vol. 59, p. 245.

SCHUTT.

:00b. Centrifugale und simultane Membranverdickungen. Jahrb. f.

wiss. Bot., vol. 35, p. 470. |

'98a. The Fertilization of Onoclea. Annals of Bot., vol. 12, p. 261.

The Haustoria of the Erysiphex. Bot. Gazette, vol. 29, p. 153.

TEE ISABEL.

The Nutrition of the Egg in Zamia. Bot. Gazette, vol. 37, p. 346.

STEVENS.

'99. The Compound Oösphere of Albugo bliti. Bot. Gazette, vol. 28,

P- 149. :

STEVENS.

:Olb. Bes and Fertilization in Albugo. Bot. Gazette, vol.

2, P. 77-

B AsPURONR.

'80. er und Zelltheilung. Jena, 1880.

STRASBURGE

'82 Ueber des Bau und Wachsthum der Zellhaüte. Jena, 1882.

genen

The Periodic Reduction of the Number of Chromosomes in the

Life History of Living Organisms. Annals of Bot., vol. 8, p. 281.

STRASBURGER.

'97a. Kerntheilung und Befruchtung bei Fucus. Jahrb. f. wiss. Bot.,

vol. 30, p. 351.

STRASBURGER.

:00b. Einige Bemerkungen zur Frage nach der doppleten Befruchtung |

bei den Angiospermen. Bot. Zeit., vol. 58, p. 293.

STRASBURGER.

:01. Ueber Plasmaverbindungen pflanzlichen Zellen. Jahrb. f. wiss.

Bot., vol. 36, p. 493

SUTTON.

:02. On the Morphology of the Chromosome Group in Brachystola

magna. Biol. Bull., vol. 4, p. 24-

SUTTON.

:03. The Chromosomes in Heredity. Biol. Bull., vol. 4, p- 231.

TANGL.

' "79°81. . Ueber offene Communicationen zwischen den Zellen des Endo- -

sperms einiger Samen. Jahrb. f. wiss. Bot., vol. 12, p. 170.

TERNETZ.

:00. Protoplasmabewegung und Fruchtkörperbildung bei Ascophanus

carneus. Jahrb. f. wiss. Bot., vol. 35, P- 273-

268 THE AMERICAN NATURALIST. | (Vor. XXXIX,

THAXTE

'96. iin towards a Monograph of the Laboulbeniacez. Mem.

Amer. Acad. Arts and Sci., vol. 12.

THOM.

'99. The Process of Fertilization in Aspidium and Adiantum. Trans.

Acad. Sci. St. Louis, vol. 9, p. 285.

TISCHLER.

:00. Untersuchungen iiber die Entwickelung des Endosperm und der

Samenschale von Corydalis cava. Verh. naturhist.-med. Ver.

Heidelberg, vol. 6, p. 351.

TOWNSEND.

'97. Der Einfluss des Zellkerns auf die Bildung der Zellhaut. Jahrb.

f. wiss. Bot., vol. 30, p. 484.

TRow.

:01. Biology and Cytology of Pythium ultimum n. sp. Annals of Bot.,

vol. 15, p. 269

TRow.

:04. On Fertilization in the Saprolegniez. Annals of Bot., vol. 18, p.

541.

WAGER

'96. On the Structure and Reproduction of Cystopus candidus Lev.

Annals of Bot., vol. to, p. 295.

WAGER. ;

'99. The Sexuality of Fungi. Annals of Bot., vol. 8, p. 575.

WAGER.

:00. On the Fertilization of Peronospora parasitica. Annals of Bot..

vol. 14, p. 263.

WEBBER.

:00. Xenia, or the Immediate Effect of Pollen in Maize. Bull. 22, Div.

; eg. Path. and Phys., U. S. Dept. of Agric |

WEBBER.

:01. Spermatogenesis and Fecundation of Zamia. Bull. 2, Bureau

Plant Ind., U. S. Dept. of Agric.

WILLIAMS.

:04b. Studies in the Dictyotacee. II. The Cytology of the Gameto-

phyte Generation. Annals of Bot., vol. 18, p. 183.

WILSON.

tha :00. The Cell in Development and Inheritance. New York, 1900.

FE.

: 04. bano: Studies on Nemalion. Annals of Bot., vol. 18, p. 607.

Worcıc

'99. Oa Fertilization in the Coniferæ.

(Russian.) Review, Bot. Zeit.,

vol. 58, p. 39, 1900. !

CORRESPONDENCE.

Editor of the American Naturalist.

Sir :— Several articles have appeared in the American Naturalist

of late on the common names of animals, and one of them introduces

the question of their etymology. “ There is in the human mind,” as

Max Müller sagely observes, “a craving after etymology, a wish to

find out why such a thing should be called by such a name”; and

this applies emphatically in the case of popular names in natural

history. |

Perhaps the most striking feature in the historical development of

plant and animal vocabularies is the extent to which words have

become metamorphosed, mutilated, deformed, or corrupted at the

hands of the people, not only in English, but in all languages. One

cannot but be impressed with the many curious travesties of the

names of plants, insects, crustaceans, fishes, and higher animals

which constitute a sort of verbal pathology, or “folk-etymology.”

There has been published recently a little essay on popular ety-

mologies, which devotes considerable attention to instances of the

latter description, and is sufficiently accurate to recommend itself

to naturalists. We refer to Zhe Folk and their Word-Lore, by

A. Smythe Palmer (London, 1904), this being a companion work to

the same author's Fo/k-Etymology.

Everyone is familiar with such typical examples of folk-etymology

as “sparrow-grass,” “cowcumber,” and * shoe-mach," which are the

popular recasting of familiar plant-names; but the majority of per-

sons are probably unaware of the close verbal affinities existing

between such words as lobster and locust, beaver and viper, croco-

dile and cockatrice, alligator and lizard, eagle-wood and alc, and

numerous other co-derivatives whose communal origin is more or

less masked. When we read in old works, for instance, that *long

oysters are a sort of crayfish,” we do not immediately perceive that

the latter word is only a modern modification of the older crevish

(also written crevis and crevice), which in turn is derived from the

same form that has yielded the French écrevisse, old-high German

Chrebiz, and modern German Krebs; nor does the word “long

oyster ” or *longoister " resolve itself at first sight into an anglicized

269

270 THE AMERICAN NATURALIST. (VoL. XXXIX.

form of the French /azgousfe, or Spanish /angosta, which lead us

back to the Latin Zocus/a. The example shows, however, how it is

possible for folk-etymology to transform crayfish, which are indeed a

variety of shell-fish, and may properly be described as long, into a

“long oyster.” So too “penny-winkle ” for the shell-fish commonly

called periwinkle, is a partial reversion to its original form ize-

wincla, ;

Many extraordinary verbal complications are brought about

through the tendency to assimilate words of a foreign or unfamiliar

aspect into something of like sound that shall be more intelligible.

Amongst the innumerable corruptions of plant-names to which this

process gives rise, may be mentioned “ bloody Mars,” a kind of

wheat, for 6/ de Mars; “Christian anthems” for chrysanthemums ;'

the various forms of Polly Andrews, Polly Ann, or polander for

polyanthus ; “rosy-dandrums” for rhododendrons ; and the correla-

tive " high-belia " and “low-belia” as offshoots from lobelia. Amus-

ing illustrations of the same tendency are furnished by the soubriquets

under which famous race-horses are known to grooms and jockeys.

Thus, Chemisette was nicknamed Jimmy's hat; Othello and Des-

demona were familiarized into *Old Fellow" and “ Thursday

Morning”; and the Irish horse Usquebaugh became to the farrier

Huskeyball.

Professor B. K. Emerson, in relating the following anecdote, offers

some instructive comments on the tendency toward assimilation, or

as he calls it, *the principle of attraction in language whereby words

without meaning to their users tend to be modified into forms which

at least appear intelligible.” Writes the genial professor’: “ Many

years ago I visited the British flagship Bellerophon in the harbor of

Bermuda, and was told that when the ship was first named, the

sailors wrestled with the sonorous but unmeanin

transformed it into ‘ Billy-ruffian ’

ligible, and belligerent

g name, and quickly

; and it became at once intel-

distal extremities.”

The significance of this and of similar incidents that are common

to everyday experience consists in their being typical of a distinct

! Geological Myths : Vice-Presidential Address.

Proc. A i : i

soy, bak orak "oc. | mer. Assoc. Adv. Sci.,

No. 460.] CORRESPONDENCE. 271

process. Words are first attracted into a form which has a meaning,

and in its turn this meaning requires a justification ; and this the

meaning itself quickly suggests. An understanding of this process

has not only solved many philological problems, but finds an appli-

cation in natural science. Emerson, for instance, in the address

referred to, is guided by it to a rational interpretation of famous

geological myths; and in the hands of Fouqué, the site of at least

one volcanic eruption known to have taken place within historical

times has been identified solely by linguistic clues of this nature.

C. R. EASTMAN.

(No. 459 was issued April 8, 1905.)

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VoL. XXXIX, No. 461 MAY, 1905

THE :

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Vor. XXXIX. May, 1905. No. 461.

AFFINITIES OF THE GENUS EQUISETUM.

DOUGLAS HOUGHTON CAMPBELL.

Tue genus Equisetum, as the survivor of an ancient race,

which has otherwise completely disappeared, is of peculiar inter-

est to the botanist. It is not strange that numerous attempts

have been made to trace its history, and to determine its rela-

tionships to the other pteridophytes, recent and fossil.

The existing species of Equisetum, about twenty-five in num-

ber, are distributed over nearly the whole world — Australia

alone, among the larger bodies of land, has no species in its

flora. Some species, e. g., Equisetum arvense, have a very wide

range, while others, like Egazsetum giganteum, are confined to a

smaller area. The genus is sometimes subdivided, but the

differences are of minor importance, and more commonly all

the species are relegated to the single genus Equisetum.

There is a general agreement in the anatomical structure, per-

haps the most marked difference being the variation in the

relation of the endodermis to the vascular bundles. Thus, in

certain species, like Eguzsetum telmateia, the ring of vascular

bundles in the internodes is surrounded by a common outer

endodermis, while in others, e. £» Equisetum hiemale, each

strand has its own sheath; while in a third type, represented

273

274 THE AMERICAN NATURALIST. [Vor. XXXIX.

by Equisetum silvaticum, there is an inner as well as an outer

endodermis, common to the whole circle of bundles. Other dif-

ferences are the presence or absence of branches at the nodes,

and the development in certain species, like Eguisetum arvense,

of special sterile and fertile shoots.

FossıL EQUISETALES.

The earliest fossils belonging to the Equisetales belong to the

genus Archzocalamites, which in many respects was very simi-

lar, as regards both its anatomy and fructification, to the genus

Equisetum. Fossils of undoubted equisetinean affinities abound

in the later Palaeozoic formations, being especially abundant in

the coal measures. Of these, the genus Calamites was especially

conspicuous. These were much more highly organized than the

living Equiseta, which more nearly resemble the more ancient

Archeocalamites, Fossils closely allied to the genus Equisetum

occur frequently, however, in later formations, being abundant

in the earlier secondary rocks.

Undoubtedly related to the Equisetales was the characteristic

Paleozoic group of Sphenophyllales, but there is a good deal of

diversity of opinion as to the possible connection of the Spheno-

phyllales with other groups of pteridophytes besides the Equise-

tales.

The genus Equisetum has been the subject of repeated

investigation, and we are now well informed concerning pretty

much all its structural details and developmental history. The

conclusions drawn from a study of these data by different ob-

servers, however, are by no means all in accord. This differ-

ence is especially marked in the attempts to decide the affinities

of the Equisetales with the other pteridophytes. It is mainly

for the purpose of examining and comparing these divergent

views that the present paper has been prepared.

Briefly stated, the following are the different views held as to

the relationships of the Equisetales : —

I. They are allied to the lycopods.

2. They are allied to the ferns.

3. They are allied to neither of the other existing classes of

pteridophytes, but have had an independent origin.

No. 461.] AFFINITIES OF EQUISETUM. 275

The first view has been strongly advocated by Scott! in

England, who bases his conclusions upon a study of the fossil

forms. In America, Jeffrey? has brought forward arguments in

favor of the same view, from a study of both the gametophyte

and sporophyte. He goes so far, indeed, as to propose a special

division of the pteridophytes into the Lycopsida, and Pterop-

sida, the former including both Equisetales and lycopods, the

latter the ferns.

As he has presented his arguments in very clear form, it may

be well to consider them somewhat in detail, to see how they

will stand the test of closer examination.

From a study of the gametophyte of Equisetum,? Jeffrey

concludes that it most nearly resembles the gametophytes of

such species of Lycopodium as Lycopodium cernuum or Lycopo-

dium inundatum. “There are in both cases, the upright fleshy

axis, and the same characteristically numerous lateral lobes. The

archegonia of Equisetum and Lycopodium are, moreover, alike,

in that in both genera they are uniformly without the basal cell,

which is found without exception in the archegonia of all the

isosporous Filicales” (/oc. cit., p. 186). He finds also that the

neck canal cell is divided vertically as in Lycopodium phlegmaria,

instead of transversely as is the case in the ferns.

Finally, in the embryo of Zguisetum hiemale and Equisetum

limosum, Jeffrey thinks that all the organs of the young sporo-

phyte, including the primary root, develop from the upper or

epibasal half of the embryo, in this respect also, showing a

resemblance to the Lycopodiales.

The points in which the adult sporophytes of Equisetum and -

Lycopodium agree, are the highly developed axis, and small

leaves ; the development of a strobilus, and the so-called “ clado-

siphonic ” vascular cylinder, or stele. It is on the basis of these

resemblances that Jeffrey proposes the establishment of his micro-

1 Studies in Fossil Botany — as well as many special papers.

21. The development, structure and affinities of the genus Equisetum. Mem.

Boston Soc. Nat. Hist., 1899; 2. Structure and development of the stem in the

Pteridophyta and Gymnosperms. Phil. Trans. Royal Soc., series B, vol. 195,

1902

3 Jeffrey, 1, p. 186.

276 THE AMERICAN NATURALIST. | (Vor. XXXIX.

phyllous and cladosiphonic Lycopsida, opposed to the megaphyl-

lous, phyllosiphonic Pteropsida.

In his comparison of the gametophyte of Equisetum with that

of Lycopodium, Jeffrey has overlooked a radical difference, to

which Goebel ! has called attention, and which has been noted

by other investigators. In the former genus, the gametophyte

is dorsiventral, as it is in the ferns, and the archegonia originate

Fig. 1, — A-C, young archegonia of Marattia douglasii; D-F, young archegonia of Egui-

, basa l

setum telmateia ; b, b

cell of the archegonium.

l cell; x, basal cell cut off before the isolation of the mother

upon the ventral or shaded surface, the more or less conspicu-

ously upright position being dependent upon light. The position

of the archegonia upon the upper side of the prothallium is a

secondary condition.

In Lycopodium, the prothallium is radially constructed, the

lobes being arranged equally about the upper part. The growth

1 4

Organographie der Pflanzen. Zweiter Theil, Heft II, p. 409.

No. 461.] AFFINITIES OF EQUISETUM. 277

is marginal, and the meristem completely surrounds the upper

part of the thallus, there being no proper apical growth as in

Equisetum.

The gametophyte of Equisetum can much more properly be

compared with that of the lower ferns like Osmunda or Marattia,

: ; = : f Bir ih

Fic. 2. — A , archegonium of Botrychium virginianum ; B, Equisetum telmateia ; C, farat.

tia Pr longitudinal division of the neck canal cell; D, Lycopodium clava-

fum; E, Lycopod.

jum phlegmaria ; 6, basal cell; o, egg cell; v, ventral canal cell; », #’,

neck canal cells. (D,after Bruchmann ; Æ, after Treub.

and in the former genus especially there are sometimes developed

lobes not essentially different from those found in the gameto-

phyte of Equisetum. | |

As to the presence or absence of the basal cell of the arche-

278 THE AMERICAN NATURALIST. (VoL. XXXIX.

gonium, this is probably not a point of fundamental importance.

The writer has taken the trouble to examine this point some-

what carefully in Equzsetum telmateia, Marattia douglasii, and

Osmunda cinnamomea. In the former, an unmistakable basal

cell was found in several instances (Fig. 1, D), although there is no

question that ordinarily it is absent. Jeffrey states that in the

species examined by him, it is universally wanting. In Marattia

it was generally present, but much less conspicuous than in most

ferns. Not infrequently, however, it was entirely wanting, as

according to Jonkman (Bor. Zeitung, 1878), it is in the species

of Marattia examined by him. Farmer says that in Angiopteris

it is also absent! In Osmunda cinnamomea, while ordinarily

present, it may be wanting.

It is thus evident that too much stress cannot be laid upon

the presence or absence of the basal cell. It is probably no

more important than the pedicel in the archegonium of the

Marchantiaceee. Marchantia polymorpha, for instance, regularly

develops such a pedicel cell, while in Targionia and Fimbriaria,

it is regularly absent, and the archegonium is closely sessile.

An interesting condition was noted in several cases in Equi-

setum (Fig. 1, Æ) where a basal cell was developed before the

final cutting off of the mother cell of the archegonium. An

exactly similar case was found in Marattia (Fig. 1, A).

Jeffrey has described a peculiarity in the archegonium of

Equisetum which he thinks points to a relationship with Lyco-

podium as in one species, Lycopodium phlegmaria (Fig. 2, E),

a similar condition has been found. This is the longitudinal

division of the neck canal cell. To judge from my own prepa-

rations of Equisetum telmateia, this rarely occurs in that species,

where the division wall is normally transverse, as it is in the

ferns (Fig. 1, F), and most other Archegoniates. A similar

longitudinal division has been observed in species of Isoetes?

In one instance a similar longitudinal division was found in

Marattia (Fig. 2, Cy

To summarize: it seems to the writer that in all respects

1 Annals of Botany, vol. 6, 1892.

á : f

Arnoldi, Bot. Zeit., 1896; Lyon, Bot. Gazette, 1904.

No. 461.] AFFINITIES OF EQUISETUM. 279

there is decidedly more resemblance between the gametophyte

of Equisetum and that of the lower ferns than there is between

it and any species of Lycopodium.

THE EMBRYO.

According to Sadebeck,! who has made a special study of the

embryo of Equisetum, the primary or basal wall of the embryo,

which is transverse, divides the embryo into an upper or epibasal

cell, and a lower or hypobasal one. From the epibasal cell is

derived the apex of the shoot ; from the hypobasal one the foot

and the primary root. My own studies upon Zguisetum_ tel.

mateta, although not complete, confirm Sadebeck's statement.

Jeffrey? thinks it doubtful whether the root in Zguisetum Ate-

male and Equisetum limosum originates from the hypobasal

region of the embryo, but to judge from his figures 7, 8, it is

by no means certain that his interpretation is correct. While

comparing the embryo of Equisetum with that of Lycopodium,

in which all of the organs of the embryo arise from the epibasal

half, he fully recognizes the fact of the presence of the sus-

pensor in the lycopods, and its absence in Equisetum. Even

if his assumption of the epibasal origin of the root were correct,

it could more aptly be compared with the embryo of Botrychium,

where he has shown? that both root and shoot are of epibasal

origin, and moreover, the cotyledon develops secondarily from

the shoot as the first foliar sheath does in Equisetum.

THE MATURE SPOROPHYTE.

The sporophyte of Equisetum, as is well known, differs

‘widely in its general structure from either the ferns or lyco-

pods. The structural type as it exists in the living horsetails is

evidently a very ancient one, and the oldest fossils belonging to

the Equisetales are not essentially different in their structure

from the living species.

! Bot. Zeit., 1877.

2 Loc. cit., p. 169.

3 The Gametophyte of Botrychium. Proc. Canad. Institute, vol. 5, 1898.

280 THE AMERICAN NATURALIST. [VoL. XXXIX.

The hollow jointed stem, the remarkably regular apical growth

of both shoot and root, and the structure and arrangement of

the vascular bundles are very different from the lycopods with

which it has been attempted to connect the Equisetales. It is

true that both the latter class and the lycopods are characterized

by relatively small leaves, but their structure and relation to the

shoot are very different in the two classes.

It may be questioned whether the excessive reduction of the

leaves found in most species of Equisetum is not a secondary

condition. The oldest known type, Archzocalamites, while

agreeing closely in its general structure with Equisetum, dif-

fered in the very much better developed leaves, which not only

were much larger than those of Equisetum, but were repeatedly

branched in a dichotomous manner, more suggestive of the

leaves of certain ferns than of any forms among the lycopods.

Their relation to the shoot, however, was precisely that of

the existing forms. The peculiar extinct order, the Spheno-

phyllales, which are admittedly of equisetaceous affinities, also

possessed dichotomously divided leaves, or wedge-shaped leaves

with dichotomous venation.

The fact that both Equisetales and lycopods have the spo-

rangial structures arranged in a strobilus or cone, can hardly be

taken as a necessary indication of relationship. The structure

of the cones in the two classes is very different, the sporangio-

phores of Equisetum being hardly comparable to the true spo-

rophylls of Lycopodium. Moreover, true strobili are known in

the fern series, as shown by the cycads, whose relationship with

the ferns is now almost universally admitted. :

While the structure of the sporangia and of the spores is

extremely characteristic in Equisetum, the development of the

sporangium is much more like that of the eusporangiate ferns

than like that of any of the Lycopodinez.

Jeffrey lays much stress upon the arrangement of the vascu-

lar bundles in Equisetum, which he thinks can be compared

better to those of the Lycopodiales than to those of the ferns.

Van Tieghem,! on the other hand, refers Equisetum to his

l Traité de Botanique.

No. 461.] AFFINITIES OF EQUISETUM. 281

“astelic’ type, to which Ophioglossum also belongs. Whether

or not Equisetum is astelic in Van Tieghem’s sense, there is a

very important respect in which it differs from the other pterido-

phytes that have been critically studied, namely, the origin of

the vascular bundles from the cortical region, and not from the

primary central cylinder. A longitudinal section of the shoot

shows an early differentiation into a central cylinder and cortex,

but it is from the latter and not from the former that the vascu-

lar strands originate, the central cylinder developing only the

pith.

Jeffrey in his study of the development of the vascular sys-

tem in the young sporophyte does not state whether the rela-

tion of the vascular strands to the primary central cylinder is

the same as in the adult sporophyte, but there is no reason why

it should be different, as otherwise the arrangement of the bun-

dles is the same.

He states that the arrangement of the bundles in the primary

shoot is the same as in the later ones, except that he finds at

the base of the shoot below the first leaf sheath, a closed ring

of vascular tissues, such as occurs at the nodes, and considers

this as a remnant of a primitive cylindrical stele or vascular

cylinder; but it is not quite clear why this does not simply

represent the first node where we should expect to find essen-

tially the same arrangement of the tissues as in the later nodes.

As in the later shoots, there extend between the nodes sep-

arate vascular strands corresponding in number to the teeth of

the leaf sheaths, — three as a rule in the primary shoot. These

fork at the nodes, and each branch joins one from the neighbor-

ing bundle, so that the vascular strands alternate in succeeding

internodes as they do in the later formed shoots.

In Archzocalamites, the earliest known type, the bundles are

continuous from one internode to another, but in the Calamites

of the Carboniferous, the same arrangement is found as in

Equisetum.

Jeffrey considers the spaces between the internodal strands

as gaps in an originally continuous cylinder, comparable to the

cylindrical stele of the ferns, or

large foliar found in the

: pom branches are given off, in the -

the ramular gaps, occurring where

282 THE AMERICAN NATURALIST. [Vor. XXXIX.

lycopods. From a study of the fossil Equisetales, especially

Archaeocalamites, he concludes that these gaps are to be con-

sidered as ramular gaps, although he admits that in Equisetum

they occur opposite the leaves. He proposes the term “ clad-

osiphonic" to designate a cylindrical stele, with ramular gaps,

such as he assumes for the Equisetales and Lycopodiales.

Admitting that the vascular system of Equisetum can be

referred to a siphonostelic type, it is hard to see how we can

reconcile Jeffrey's idea of cladosiphony with the facts. So far

as we can see there is absolutely no difference in the arrange-

ment of the bundles of the internodes and their intervening

spaces in shoots which develop branches, and those which are

without them. In all cases, the number of internodal strands

— and, of course, that of the gaps between them — corresponds

to the number of leaf traces developed from the foliar sheath.

The gaps are equally present in the primary unbranched shoot,

and in the densely branched sterile shoots of Equisetum arvense

or Equisetum telmateia. It certainly seems hardly reasonable

to suppose that an ideal branch — so to speak — could cause

the development of a ramular gap, when no actual branch is

present.

. Jeffrey lays stress upon the fact that in Archaeocalamites, the

branches are really opposite the spaces between the internodal

vascular strands; but it appears! that Archzeocalamites was

often very sparingly branched, but this does not seem to bear

any relation to the presence of the alleged ramular gaps, which

are perfectly developed whether branches are present or not.

We see no reason why we should try to reduce the vascular

system in the Equisetales to either of the types found in the

other phyla of pteridophytes. The peculiar character of the

stem, with its hollow jointed structure, would naturally involve

quite a different arrangement of the tissues. Moreover, as has

already been indicated, the origin of the vascular strands is

entirely different from that of the typically axial vascular cylin-

ders of the other classes. There is no valid reason why the

separate strands in Equisetum may not have existed from the

1 a

Scott, Zoe. cit., p. 65: Potonie, Lehrbuch der Pflanzenpaleontologie, 1899.

No. 461.] AFFINITIES OF EQUISETUM. 283

first. The oldest fossils show the same type, and in the embryo,

before any trace of the vascular bundles can be seen, there is

developed the three-leaved primary foliar sheath, and corre-

sponding to the three teeth of the foliar sheath, are developed

simultaneously the three vascular strands of the first internode.

THE SPHENOPHYLLALES.

The Sphenophyllales are exclusively fossil forms which show

evident affinities with the Equisetales, from which they differ

especially in the arrangement of the tissues of the stem.

Instead of the large central cavity found in the stem of Equi-

setum, Sphenophyllum has an axial solid vascular cylinder more

like that of the modern lycopodiaceous forms than like any

other existing pteridophytes.

Scott! considers that the Sphenophyllales are to some extent

intermediate between Equisetales and Lycopodiales, basing his

opinion mainly upon the anatomical characters, especially those

of the stem. The peculiar fossil Cheirostrobus? he especially

considers a synthetic type, having the sporangia of the Equi-

setum type, but the vascular system of a lycopod.

Potonie? holds that the Sphenophyllales are an early offshoot

of the equisetaceous series, perhaps directly connected with

Archzocalamites. The characteristic triarch or hexarch bundle

of the stem suggests a three-sided apical cell like that of Equise-

tum, but in the Psilotaceze, which are commonly associated with

the Lycopodiales, there is a somewhat similar type of stele, and

these forms also have a single tetrahedral initial cell in the

shoot.

One objection to considering the Sphenophyllales a synthetic

type is that all the existing types of pteridophytes were clearly

differentiated in formations earlier than any in which remains of

the Sphenophyllales certainly occur.

1 Studies in Fossil Botany, 1900.

2 Joc. cit. pp. 106-114.

3 Joe. cit, p. 180. ©

284 THE AMERICAN NATURALIST. (VoL: XXXIX.

The peculiar, jointed, hollow stem, with the characteristic

arrangement of the bundles, except for their alternation in

succeeding internodes, is as marked in the earliest Equisetales

as it is in the existing genus, and cannot readily be derived from

either the type of the ferns or lycopods, both of which are

clearly recognizable in the formations where they first occur.

So far as we can judge from the geological record, the central

solid stele of Sphenophyllum is a more recent development than

the separated vascular strands of the typical Equisetales, as

exemplified by Archzeocalamites.

CONCLUSIONS.

As we have endeavored to show, the gametophyte of Equise-

tum resembles that of the eusporangiate ferns rather than Lyco-

podium, both in its dorsiventral character, and method of growth,

and especially in the large multiciliate spermatozoids. We be-

lieve that these resemblances indicate a real, although extremely

remote, relationship with the lower ferns.

The early divisions of the embryo are not unlike those in the

fern embryo, but the early preponderance of the shoot, and the

subordination of the leaves, very soon produce an extremely dif-

ferent type of sporophyte, and it is highly probable that the

peculiarities of the sporophyte were established at a very remote

period, and-are not modifications of another type. The dichoto-

mously divided leaves of the older Equisetales and Spheno-

phyllales are somewhat reminiscent of those of some ferns,

although it is not at all likely that there is any direct genetic

relationship between these.

The most probable conclusion to be reached, in view of the

evidence at hand, would seem to be that the two series, the

ferns and Equisetacez, are descended from a common stock, in

which the gametophyte was not unlike that of the existing spe-

cies of Equisetum and the lower eusporangiate ferns. It must

be assumed, however, that the peculiarities of the sporophytes

became established at so remote a period that one cannot say

that either was derived from the other — ;. e., from the same

ancestral stock represented by the gametophyte as it now exists

No. 461] AFFINITIES OF EQUISETUM. 285

in the two classes, there arose quite independently two types of

sporophyte : one distinguished by a preponderant development of

the shoot, the other marked by the great development of the leaf

structures.

Neither of these classes is at all related to the Lycopods,

which show strong evidences of being derived independently

from a very different type of gametophyte.

STANFORD UNIVERSITY.

MOVEMENTS OF DIATOMS AND OTHER MICRO-

SCOPIC PLANTS.

DANIEL D. JACKSON.

Few subjects in the domain of cryptogamic botany have given

rise to more speculation and conflicting theories than have the

studies into the cause of the apparently voluntary movements of

diatoms. From time to time for the past twelve years the

author has been confronted with this seemingly fruitless subject,

and only recently, almost by accident, has the problem been

solved.

It was early shown by examination in closed cells that the

phenomenon was not due to external currents’set up in the sur-

rounding liquid, but that the power of motion came from the

organism itself. Largely on account of these movements, which

appeared to be spontaneous and voluntary, the diatoms were

originally classed in the animal kingdom.

The first theory which naturally presented itself was that

they move as do the Infusoria by means of vibrating hair-like

cilia or flagella. Later certain authors claimed to have seen

protoplasmic processes similar to those of the rhizopods pro-

truding from the small openings in the frustule of the organism.

Then came the theory of Onderdonk! which described the

progression as due to a thin fluid mass in rhythmical motion

covering the surface of the diatom.

Nägeli suggested that the motion is due to endosmotic and

exosmotic currents, and H. L. Smith? after much study of the

subject came to the conclusion “ that the motion of the Naviculae

is due to injection and expulsion of water, and that these cur-

rents are caused by different tensions of the internal membran-

ous sac in the two halves of the frustules."

1 The Movements of Diatoms. Zhe Microscope, August, 1890.

Contribution to the Life History of the Diatomaceæ. Proc, Amer. Soc.

Microscopists, 1888.

287

288 THE AMERICAN NATURALIST. (VoL. XXXIX.

In order to prove this theory, Professor Smith showed by

means of suspended indigo that when the diatom moves forward

the particles of indigo gather around the central nodule of the

valve and form a small mass which turns on itself just as if it

was impelled by a jet of water proceeding from the valve at this

point. Each of these little turbulent spheres after having

acquired a certain size, falls apart and the particles which com-

pose it are driven along the valves from front to back and accu-

mulate behind the extremity of the frustule which, according to

its progression, woüld be considered the rear. The particles

move as if they were subjected to a current going from front to

back, and reverse when the motion is reversed. That these cur-

rents exist there can be no doubt, but that the motive power is

not due to the expulsion of water will shortly be demonstrated.

The first intimation of the true nature of this motion was

suggested by the action of a lithia tablet in a glass of water.

The bubbles of carbonicacid gas given off set up the exact

. motions in the tablet that have been so often described for the

movements of diatoms: * A sudden advance in a straight line, a

little hesitation, then other rectilinear movements, and, after a

short pause, a return upon nearly the same path by similar

movements."

Repeated experiments with compressed pellets evolving gas

have shown that this is the usual motion produced by the evolu-

tion of gas bubbles, and when pellets were made of the same

shape as Navicula the movements of these diatoms were per-

fectly duplicated. Boat-shaped pieces of aluminum two milli-

meters thick were then made and on them were cut longitudinal

grooves to resemble those of the diatom. When placed in

strong caustic soda solution the movements of the metal pro-

duced by the evolution of hydrogen gas again duplicated those

of the diatom ina remarkable manner. The metal having the

grooves had a greater power of motion than that without th

grooves.

If we consider that the diatom contains chlorophyll bands which

"a exposed to a strong light rapidly evolve oxygen, and if we

take into account the fact that the motion does not take place

unless the light is fairly strong, we have then a conception of |

the true nature of the movements of these organisms.

No. 461.] MOVEMENTS OF DIATOMS. 289

Streams of oxygen may be readily seen evolving from all parts

of many of the larger aquatic plants when submerged in water

and exposed to strong light, but in the diatom while the gas pro-

duced is large in amount compared with the size of the organism,

the actual amount evolved is so small that it is taken into solu-

tion almost immediately. That such evolution takes place, how-

ever, is shown by Professor Smith’s experiments with indigo.

If now we examine the artificial diatom made of aluminum and

placed in strong caustic solution we find that the bubbles from

all sides come together and rise in a line corresponding to the

median line or raphe of the organism, and that if indigo is placed

in the liquid it collects and rotates near the central nodule just

as described by Professor Smith to prove his theory of the pres-

ence of water currents.

It is therefore evident that the motion of diatoms is caused by

the impelling force of the bubbles of oxygen evolved, and that

the direction of the movement is due to the relatively larger

amount of oxygen set free first from the forward and then from

the rear half of the organism. This accounts for the hesitancy

and irregular movements as well as the motion forward and back-

ward over the same course.

The evolving gas seems to act at times as a propeller to push

the organism forward and at other times to exert a pulling action

to raise the growth on end. The various movements described

are the resultants of varying proportions of both of these active

forces.

The fact that a longitudinal groove on the under side of the

artificial diatom causes it to become more active, due to the

expulsion of the gas along the line of the groove, explains the

greater activity of the Raphideze.

The most interesting and peculiar movements among diatoms

are those of Baci/laria paradoxa whose frustules slide over each

other in a longitudinal direction until they are all but detached

and then stop, reverse their motion and slide back again in the

opposite direction until they are again almost separated. When

the diatoms are active, these alternating movements take place

with very considerable regularity. It is probable that the indi-

viduals in a group of Bacillaria are joined together much more

290 THE AMERICAN NATURALIST. (VoL. XXXIX.

loosely than other laterally attached genera and that when a

forward movement takes place in the outer individual it is

arrested by capillarity just before the diatom is completely

detached.

It can now be readily seen that the strange movements of

the other microscopic plants may be explained as also due to

the evolution of oxygen gas. While the movements of desmids

are not as strongly marked as those of diatoms, many of them,

notably Penium and Closterium, have often been described as

having a power of independent motion, and Stahl! found that

this motion is greatly affected by light.

The best account of the movements of desmids has been

given by Klebs? This author speaks of four kinds of move-

ments in desmids, viz. : —

(1) A forward motion on the surface, one end of each cell

touching the bottom, while the other end is more or less ele-

vated and oscillates backwards and forwards. ae

(2) An elevation in a vertical direction from the substratum,

the free end making wide circular movéments.

(3) A similar motion, followed by an alternate sinking of the

free end and elevation of the other end.

(4) An oblique elevation, so that both ends touch the bot-

tom — lateral movements in this position; then an elevation

and circular motion of one end, and a sinking again to an

oblique or horizontal position.

This observer considered these movements to be due to an

exudation of mucilage, and the first two to the formation, dur-

ing the action, of a filament of mucilage by which the desmid

IS temporarily attached to thé bottom and which gradually

lengthens.

These four kinds of movements are very easily explained by

the theory of the evolution of gas, and by regulating the condi-

tons they can be exactly reproduced in the artificial desmids

made of aluminum. In this case strips of thin aluminum foil

should be used. When the gas production is very strong at one

; Verhandl. Phys. med. Gesellsch. Würzburg, 1880, p. 24.

Biol. Centralblatt, 188 5, P. 353.

No. 461.] MOVEMENTS OF DIATOMS. 291

end, the desmid will be raised to a vertical position and will take

up oscillating or circular movements.

If we now pass to a consideration of like movements in the

Cyanophycez, the same explanation holds true for Oscillaria

which often takes up a waving or circular motion when attached

at one end. This movement is well described by Griffith and

Henfrey ! as follows : “ The ends of the filaments emerge from

their sheaths, the young extremities being apparently devoid of

their coat ; their ends wave backward and forward, somewhat as

the forepart of the bodies of certain caterpillars are waved when

they stand on their prolegs with the head reared up." The

authors attribute this motion to “irregular contraction of the

different parts of the protoplasm.”

The free-swimming species of Nostoc all have a spontaneous

power of active motion in water, and in all of the filiform orders

of the Cyanophycez, detached portions of the filament known as

hormogones also have the power of spontaneous motion. All of

these movements can be exactly duplicated with lithia tablets in

water or with aluminum of the proper weight and shape immersed

in strong caustic solution, and are also undoubtedly caused by

the strong evolution of oxygen gas due to the activity of the

chiorophyl present in the organisms.

MT. PROSPECT LABORATORY,

BROOKLYN, N. Y.

1 Micrographic Dictionary, P- 561.

SYNOPSES OF NORTH AMERICAN

INVERTEBRATES.

XX. FAMILIES AND GENERA OF ÄRANEIDA.

NATHAN BANKS.

Tue body of a spider is very distinctly divided into two parts :

the anterior, or cephalothorax, or carapace, and the posterior, or

abdomen. The cephalothorax is supposed to be the equivalent

of the head and thorax of in-

sects, Near the middle of

the cephalothorax is a dorsal

or median groove; from this

groove radiate furrows, called

radial furrows. The region

of the cephalothorax between

the anterior pair of furrows

is called the pars cephalica,

or head; the part behind is

known as pars thoracica.

The eyes are situated upon

the front part of the pars

cephalica; the region they

occupy is known as the eye-

region, eye-area, Or ocular

area. The eyes are usually

eight in number, sometimes

six, more rarely two or none.

They are arranged in trans-

verse rows, often two, some-

mandible; 4, eyes; <, pars cepha-

times three or four. Refer- cell e, dorsal groove; g, ab-

ences to the eyes are in the Jemen; + spinnerei; e apti

form of abbreviations, S. E.,

meaning side eyes; A. E. anterior eyes; P. E., posterior eyes ;

M. E., middle eyes; P. M. E, posterior middle eyes; A. 5. Es

| 293

294 THE AMERICAN NATURALIST. (Vor. XXXIX.

anterior side eyes, etc. Sometimes the most posterior eyes are

called the dorsal eyes. An eye-row is either straight or curved.

When the S. E. of a row are farther back than the M. E. of

that row, the row is said to be recurved ; when the S. E. are

more forward, the row is procurved. Dark-colored eyes are con-

sidered to be diurnal in function, and pale eyes nocturnal.

Many spiders have both kinds and the difference in appearance

of the two is often very striking.

The arrangement of the eyes

is of the greatest importance

in systematic araneology. The

space between theanterior eye-

row and the front or clypeal

margin of the cephalothorax is

called the clypeus, or fillet.

Attached just below the clypeal

margin are the mandibles, jaws,

falces, or chelicerze, as they are

variously termed. Each is of

two parts: the basal joint, or

larger part, and the fang, or api-

cal part. The fang fits down

into a groove of the basal joint,

which is often margined with a

few small teeth. The poison

s glands open near the tip of the

ro. ENS fang 4, mandible; c, maxilla; fang. The mandibles are usually

et od vertical, sometimes uplifted, or

tralis; x, spinnerets; s, coxa; 4, femur; v, pa- porrect. | Sometimes they are

uds divergent, and in some cases the

basal part is swollen above in

front, and the mandible is then said to be geniculate. At the

outer base of each basal joint there is, in some families, a small

area separated from the rest of the surface; this is styled the

boss, or lateral condyle.

The mouth-parts seen from below are a median piece, the lip

or labium, and a piece on each side, the maxille, or endites.

In some cases the maxillae show an oblique furrow or impres-

> A

No. 461.) NORTH AMERICAN INVERTEBRATES. 295

sion. Each maxilla bears a jointed appendage, the palpus. In

the female, the palpus is always simple, but in the male, when

mature, the last joint is enlarged, concave within, and furnished

with a number of more or less corneous and curved pieces,

which serve as accessory sexual organs. The shape of these

male palpi is of great value in the study of species. The

sternum is the ventral plate of the cephalothorax; it is sur-

rounded by the eight legs. In some species there are scars

or impressions on the sternum. The legs are numbered from

before backward as follows: I, II, III, IV. They are seven-

jointed, each joint from the basal outward known as follows :

coxa, trochanter, femur, pa-

tella, tibia, metatarsus or pro-

tarsus, and tarsus; in a few

forms there is a small eighth

joint, the onychium. At the

tip of the tarsus, or onychium

if present, are two claws, equal

in size; below and between

them, in some families is a

third. chaw: Gomina M Her with two claws and brush, and with

place of the third claw there

is a dense brush or fascicle of hair. The claws are often toothed

or pectinate. In a few groups there are specialized branched

hairs at the tip of the tarsus which may act as accessory claws.

Sometimes there is a brush of hairs along the lower side of the

tarsus or metatarsus ; this is called a scopula. Sometimes there

is a row of serrate bristles under tarsus IV ; this is known as a

Mot ey

comb. .

The abdomen is joined to the cephalothorax by a slender ped-

icel. At or near the tip of the abdomen on the

under or ventral side are the spinning organs,

or spinnerets. They are of three pairs, the mid-

dle pair smaller and concealed by the other two.

Sometimes one pair is very plainly of two joints.

At the base of the lower pair there is sometimes

a transverse surface provided with (Fig. 4) spinning tubes simi-

lar to those of the spinnerets;; this is the cribellum. Comple-

FıG. 4.— Cribellum.

296 THE AMERICAN NATURALIST: (VoL. XXXIX.

mentary to this in function is a row of stiff hairs or bristles on

each posterior metatarsus, known as the calamistrum (Fig. 5).

The spider possessing these accessory spinning organs can pro-

duce a peculiar curled silk by using the calamistrum to comb out

the threads from the cribellum. In some cases there is a coni-

cal piece between the lower pair of the spinnerets, termed the

colulus. In the tarantulas and allied spiders there is a small

post-abdomen above the spinnerets. Near the base of the spin-

nerets is a pair of stigmata or tracheal spiracles; these are

sometimes placed more anteriorly, and

even as near the base as the tip of the

abdomen. When so situated a trans-

verse fold or furrow is formed, known

as the ventral furrow, or rima ventralis. Near the base of the

abdominal venter is a transverse slit on each side. These are

the lung-slits or epigastric furrows, which open into the breath-

ing organs called lung-books. In some spiders there are two

pairs of these slits, or there may be a tracheal spiracle behind

the first pair. The hardened cuticle over the lung-books forms

the epigastric plates. Between the plates on the median line is

the opening of the reproductive organs. The genital aperture

of the female is termed the epigynum or vulva, and that of the

male, small and inconspicuous, is the epiandrium. The epigy-

num is often of a very complicated nature, and is of much value

in the study of species. In some cases there is a pointed piece

projecting below the abdomen known as the finger of the epigy-

num. The furrow behind the epigynum is called the rima geni-

talis. In some forms there are corneous plates, shields, or

scut€ on the abdomen, either above or below. Small circular

spots are sometimes called sigille.

The legs and body are clothed with hairs, bristles, scales, or

articulated Spines. The arrangement of the latter upon the

legs is often of great systematic value. If there are two rows

of these under tibia I, each row of three spines, then tibia I is

said to have spines 3-3. Sometimes these hairs or bristles form

tufts, crests, or fringes. On the dorsum of the abdomen there

Is sometimes a leaflike mark known as the folium. In some

cases there are short, oblique marks in pairs on the dorsum;

Fic. 5.— Calamistrum.

No. 461] WORTH AMERICAN INVERTEBRATES. 297

these are called chevrons. The legs may have longitudinal

marks— stripes ; or transverse marks— bands.

Spiders at birth are often very different from their later

stages, so that it is impracticable to identify them by tables

prepared for adults. However, many spiders when one or two

months from maturity are sufficiently similar to their parents

to be placed in the proper genus. None but specialists should

attempt the specific identification of immature spiders. At

maturity the female has her epigynum exposed, and the male has

the complicated structures of the palpi uncovered. Spiders

without these developments should not be studied by the begin-

ner. There are a few forms of uncertain generic position

which have not been included in the tables. They are rare,

doubtless more so than various new generic forms that have not

yet been collected, though occurring in our country. The spider

fauna of many portions of the South and West has been only

slightly explored, while a closer examination of our southern

borderland will reveal various genera now known to occur in

Central America only. Nevertheless the more common spiders

in any portion of our country will be found in the following

tables

MYGALOMORPHA.

Two pairs of lung-slits on venter of abdomen; fangs of mandibles

moving vertically, parallel to each other.

1. Legs very long and slender, femur I longer than body Hypochilidz.

Legs short and heavy, femur I shorter than body . Theraphosid.

ARACHNOMORPHA.

But one pair of lung-slits on venter of abdomen; fangs of mandibles

moving somewhat horizontally, toward each other.

I. Without eyes ; small pale cave "e rn: Linyphiide.

With six or eight eyes ^ qu d.

2. With eight eyes ; “a

With but six eyes .

3. Alleyes close together upon a Landi bare or eminence ; large species,

yellowish brown or brown in color San

All eyes not situated upon a small meliin tubercle i

4- Apex of abdomen surrounded by a circle of bent hairs ; sia eripi

298 THE AMERICAN NATURALIST. (VoL. XXXIX.

with flat cephalothorax, maxilla curved around lip, and the posterior,

middle eyes elongate and curved ; eyes not in two transverse rows

Urocteide.

No circle of bent hairs around tip of abdomen . , I es

5. With a cribellum and calamistrum in female . i ; oe

Without cribellum and calamistrum . j : EY T

6. Eyes always in three or four transverse rows ; eyes of next to last row

extremely small, the middle eyes of first row (or the first row in Lys-

somanes) are very much larger than other eyes ; clypeus always vertical,

never sloping ; cephalothorax never very broad, e rather short ; jump-

ing spiders . Attide.

Eyes in two or Wed i rows; Fides in dde rows, BÀ the middle of

first row are not greatly larger than any others, and those of second

row not greatly smaller than others .

7. Each tarsus with three claws: spinning nie: or iere eyes are dini in

three rows 1 : : i i à

Each tarsus iu but ı two ides: never spinning webs; eyes nidi in

three rows; S. E.rarely contiguous ; never with but two spinnerets 8.

8. Posterior eye-row so much procurved as to represent two rows, the P.

E. oval; maxille long and tapering; fang of mandibles very long;

trochanters longer than usual, anterior coxze much longer than others

Prodidomidz.

Without such combination of en : p

9. P. M. E. large, closer to the small A. S. E. than di uid are to die A.

M. E., which are also small; tarsi with en cephalothorax not

broad an flat, legs rather lticiide ; . Ctenide.

P. M. E. not as close to A. S. E. as lather are to A. M. E., or if Ys

then eyes nearly equal in size

10. P. M. E. black ; legs I and II Bod asi is, articulated so En

the anterior surface is directed upward. Second pair of legs nearly

always as long as the fourth, or longer, and about as large and long as

leg I; spinnerets not prominent; cephalothorax pu broad p

abdomen often depressed

. M. E. pale, only A. M. E. idu: bes I "d II not ees

leg II usually noticeably shorter or nal than either leg IV orleg I;

cephalothorax longer t3

11. A. M. E. some distance from cly peu margin, tarsi vee not spial ;

spiders of medium size . Thomiside.

A. M. E. close to clypeal ER » cephalothorax dettes, tarsi heavily

scopulate, mostly large spiders 12.

I2. Tarsal claws pectinate, maxillae not inclined over E very ree spiders

arasside.

Tarsal claws smooth, maxillz inclined over lip ; spiders of Sada size

odariidz.

13. Lower spinnerets distinctly separated, rather long and prominent ;

No. 461] NORTH AMERICAN INVERTEBRATES. 299

maxillae with an obliquely transverse furrow or groove, outer side often

concave ; abdomen often depresse Drassidz.

Lower spinnerets contiguous ; roit canal without furrow, outer.

side convex . : . Clubionide.

14. With but two spinners which are very v rironitiiant, but not two-jointed,

eyes in two rows, legs short and heavy ; maxilla inclined over lip

Zodariide.

With six spinnerets 15.

15. Three eyes on each side in a group, the rp M. E. waiti the E s. E.;

cephalothorax rounded and flat, the pars cephalica very small; legs

long and without spines, maxillae surrounding the lip . . Pholcide.

M. E. never touch P.S. E.; only two eyes in side group, pars

cephalica occupying entire front of cephalothorax : ; 16.

16. Eyes in two rows, more or less curved ; no scopula; P. s. E. never

much larger than eyes of front row; when P. M. E. are as far apart as

A. S. E. (which is rare) then the legs are not spined 1

Eyes usually in three (or four) rows, when in two rows, ien the p. S. E.

are much larger than the eyes of front row, or the tarsi are scopulate, or

the P. M. E. are farther apart than the A. S. E. en and the

legs spined . 24.

17. Legs I and II long, with rows of two kindà o spines, one TUR and

the other in between are very short and curved Mimetide.

No such spine arrangement on legs : . . . 18.

18. Males only:— mandibles concave trite in did and bowed outward

in middle ; tibia of male palpus with a process on outer side at base

Dictynide.

Males and females : — former never with such mandibles, x tibia of

palpus not often armed at base 19.

19. Upper spinnerets long and we or ve with the mandibles

geniculate at base, and the A. M. E. only dark ; no comb on hind tarsi ;

legs with spines; making flat irregular we ebs . e

Upper spinnerets not long and two-jointed, additis : not promiuendy

geniculate at base, other eyes besides A. M. E. are dark; S. E. often

contiguous .

20. Males only : — A. M: E. ae diameter from d margin upper

spinnerets not two-jointed Dictynidæ

Males and females : — upper ipinaereis two

are some distance from clypeal m argin

21. A comb on hind tarsus; legs usually withou

globose ; maxilla inclined over lip ; clypeus as high as T E

Jointed, or ese the A. M. E.

Agalenide.

t spinel; ‘abdomen often

eridiidz.

No such comb; maxillz usually less inclined over T spines =

present on legs

22. Epigynum of feinale: a ale slit; ; malt m has a idu on end oa

300 THE AMERICAN NATURALIST. [VorL. XXXIX.

tarsus terminating in a simple tube; legs rather short, body never high

and broad; mandibles not large and porrect . ; 1 cytodide.

Male palpus has the palpal organ quite complicated, and the tarsus

partly covers it; the epigynum is more than a slit, else the mandibles are

large and porrect, or the abdomen very elongate , ; UNS.

23. At base of mandibles on outer side is a striate or roughened area;

clypeus high, higher than height of eye-area; no accessory claws (or

serrate bristles) at tip of tarsi; male palpal organ with a tarsal hook ;

making irregular webs . " ; P : . . Linyphiide.

At base of mandibles there is no such roughened area, but usually a

smooth swelling or boss; clypeus low, usually not as high as height of

eye-area ; accessory claws (or serrate bristles) at tip of tarsi; making

geometric webs . : i : ; i ‘ . . Epeirid.

24. Two eyes only in anterior row; clypeus not as high as ocular area 25.

Usually four eyes in front row, if but two, then clypeus is much higher

than ocular area : y í i S : . : . A

25. Eyes in four rows, the anterior practically at the clypeal margin,

abdomen long and slender . à : . . Podophthalmide.

Eyes not in four rows, the anterior row some distance from clypeal

margin; P. M. E. closer to A. S. E. than latter to A. M. E. ; body not

long and slender . diua à : . i i Ctenidze.

26. Males only : — eyes of second row very much larger than all other eyes

together, abdomen long and linear TU i . A Dinopidz.

Males only : — abdomen not long and linear, eyes not as above ; head

very low in front ; at tips of tarsi are accessory claws as in Epeiridz, leg

I much larger and longer than others . ; i : Uloboridz.

Males and females: — Eyes of second row never so large ; abdomen

not linear; head rather high or else leg T not larger and longer than leg

V ; no accessory claws at tips of tarsi ; : ‘ ; 3 5

27. But two eyes in anterior row, or if four, then median eyes are very

small and fully three times their diameter from the side eyes ; clypeus

Wen Oxyopide.

Four eyes in anterior row, middle eyes never so very much smaller nor

so far from the side eyes; clypeus much lower ; : . . 28.

. 28. Eyes in three rows, 4-2-2, those of anterior row very much smaller

an others; cephalothorax rather long and narrow, clypeus nearly verti-

cal; no spur at tip of tibia of male palpus i ; i Lycosidz.

Eyes in two curved rows, those of anterior row not so much smaller

than others ; the cephalothorax broad and flattened ; clypeus often slop-

Ing; a spur at tip of tibia of male palpus : : i Pisauridz.

29. Eyes in three rows, 42-2, those of second row very much larger than

all other eyes together, abdomen very long and linear . Dinopide.

No such eye conditions; abdomen shorter . í i ‘ rue

30. S. E. as far apart as M. E.; clypeus low ; cephalothorax broad

Uloboridz.

No. 461] NORTH AMERICAN INVERTEBRATES. 301

S. E. closer to each other than are the M. E. pesa eel or if low,

then cephalothorax is not unusually broad .

31. Eyes plainly in three groups of two each ; dived species . 32;

Eyes in two groups of three each, or else all in one group; small, pale

Dictynide.

species 33

32. A pair of sine rem behind lung in anterior d igi and

heavy, never small species . Dysderidæ.

No such stigmata ; legs siai spines, ondi sali palpus at tip of

tarsus, lip united to sternum . Scytodide.

33. Cephalothorax broad and flat; lee long ii cone; none of femora

thickened, mandibles small . . Pholcide.

Cephalothorax more elongate, not flat; nini: of normalsize 34.

34. Legs with spines, and not slender; no cribellum ; male palpus partly

covered by tarsus, dark species : Agalenidz.

Legs without spines, or else very dened asnally visit and pale species

35. Female with cribellum and calamistrum ; male has palpal organ partly

covered by tarsus; no shields on abdomen, legs without spines

ictynide.

Female without cribellum or calamistrum ; male has palpal organ at

tip of tarsus, wholly exposed . 6.

36. Cephalothorax highest in front i miiie; ieg I long and stouter j iban

others; three claws to each tarsus . Leptonetide.

Cephalothorax highest behind middle: : femora IV ee at base ;

two claws to each tarsus i : i Oónopidz.

THERAPHOSIDE.

Palpus arising from the outer basal side of the maxillz Atypinz.

Palpus arising from near or at tip of maxille — . . Theraphosine.

Atypine.

We have but one genus, Atypus, which is rare in the eastern States,

with apparently two species. They live in silken tubes which extend some

distance above the ground.

Theraphosine.

ı. Tarsi with a third claw; no tuft or fascicle of hairs attip - C x

Tarsi with but two claws, a fascicle of hairs at ti

2. Post-abdomen some distance nn spinnerets ; doii groove ing

tudinal ; furrow of mandibles indistin

Post-abdomen just above se dorsal groove transverse or

es furrow of mandibles distinct - : 3

302 THE AMERICAN NATURALIST. [Vor. XXXIX.

3. Upper spinnerets rather short, last joint short and obtuse ; mandibles

with a clusterof teeth, or rastellum, in front

Upper spinnerets rh and last joint slender ; BETEN ie ras-

telum . rs A

4. Tarsi and metatarsi 1 parte Pieds: all tarsi mies

Brachythele.

Tarsi and metatarsi I not scopulate ; hind tarsi with spines Evagrus.

Tibia III with a deep sulcation above at base

No such sulcation :

6. Tip of abdomen broadly Musicute; bing ai an RR duda: online

Cyclocosmia.

Tip of abdomen normal , Pachylomerus.

7. Tarsi I and II not onusta: with stoutspines . Mes

Tarsi I and II scopulate

8. Sternal impressions large, close other. und far ER margin

Sternal impressions small and near the margin

Mandibles with four long, equal teeth in front HACEN the manaii

Actinoxia.

Rastellum of many irregular spines . EL.

10. Tarsus I equal to metatarsus I, latter with is itte; en

Amblyocarenum.

Tarsus I shorter than metatarsus I, latter with many spines

Aptostichus.

. With but four spinnerets . i 5 i à Brachybothrium.

With six spinnerets . 12.

. Apical joint of upper spinnerets mack Moser thon EIER mad

bles without a rastellum ; no sternal i impressions . Hexura.

Apical joint of upper spinnerets barely longer than Dre, ; mandi-

bles with a rastellum ; two pairs of small sternal i impressions

Atypoides.

13. Tibie and metatarsi III and IV with very few spines ; tarsi shorter

and broader . 15.

Tibiz and metatarsi IH nd IV with many spines ; tarsi Inge 14.

14. Metatarsi I scopulate to base, rarely with basal spines Eurypelma.

Metatarsi I not scopulate to base ; basal spines present Rhechostica.

15. Eyes of anterior row scarcely unequal, forming a strongly procurved

—

a Avicularia.

Eyes of anterior à row distiuclly sinu, incid a seni straight row

Tapinauchenius.

FILISTATIDE.

We have but one genus in this country, Filistata, and probably but one

species, which is frequent about buildings in the southern States.

No. 461] NORTH AMERICAN INVERTEBRATES. 393

UROCTEIDE.

We have but one genus in this country, Thalamia Hentz, with two

species in the South.

LEPTONETIDE.

1. The six eyes in two groups, four in a row in front, and two behind

Leptoneta.

Thesix eyes in three groups of two each, two in the middle and two

each side

: : C 2

2. S. E. form a diverging tius, and uch by their side i . Usofia.

S. E. touch at one point, and form a single opening within

Ochyrocera.

OÖNOPIDE.

Abdomen soft, globose E o : Orchestina.

Abdomen with corneous ide doigt i : Gamasomorpha.

SCYTODIDE.

1. With eight eyes ; body dark . - ‘ . ; - Plectreurys.

With but six eyes š a

2. Cephalothorax elevated behind; eye- ona widely itpaitalij three claws

to each tarsus ; palpus of female with a claw at tip . . Scytodes.

Cephalothorax not elevated behind; eye-groups more approximate ;

palpus of female without claw at ti a

3. Three claws to each tarsus ; anterior evexow nen inde; cephao

thorax very slender Di

Two claws to each tarsus ; anterior eyerow anak: opto

broader : : : : ; Loxosceles.

Fic. 6.— Cephalothorax of Scytodes.

PHOLCIDE.

1. With six eyes situated rather close together upon a prominent eminence

Modisimus.

Eyes not on an eminence, and in two groups

304 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

2. With but six eyes ‘ : i : . Spermophora.

With eight eyes . 4.

3. A. M. E. much closer to Seach her thas to É S. E.; finora very rone

abdomen elongate . . Pholcus.

. M. E. as close to A. S. E. as’ to see TS shone globose 4

4. Femur I not twice the length of xvi and shorter than femur

IV He

Peer I twice as PR as bes con a 5.

5. Posterior Nue slightly procurved ; feu I me das IV

silochorus.

Posterior eye-row slightly recurved ; femur I shorter than IV

Physocyclus.

DYSDERIDE.

1, Leg III directed backward ; spines on sides of tibie IV ; tarsi scarcely

one fourth the length of metatarsi; no spines under metatarsi I

Dysdera.

Leg III directed forward ; no spines on sides of tibie IV; tarsi je

one third the length of metatarsi; spines under metatarsi I

2. The M. E. rather closer to A. S. E. than toP. S.E. . ‘ Sauce

The M. E. closer to P, S: E. than to A.S.E. . ie . Ariadne.

PRODIDOMIDE.

This is represented in our country by but one genus, Prodidomus Hentz,

with one species, found in dark situations in houses in the southern States.

An allied genus, Zimiris, occurs in Mexico, and differs from Prodidomus in

having the inferior spinnerets very much longer than the others.

ZODARIIDE.

With but two distinct spinnerets ; cephalothorax rather er tarsi with

3 claws Lutic

With more ihi two spinners Gib halothorax rather dati tarsi with

but two claws : E Hoimalonychibs ;

DRASSIDE.

t. Mandibles with a plate or lobe on under side behind the fang ; posterior

eye-row plainly recurved . x

Mandibles without such plate, init one or two weis poaterici eyerow

often procurved or straight, rarely a little recurved 3

2. Posterior eye-row broader than anterior row; P. S. É. not N larger

an P. M. E.; head broad . E Tu UE Gnaphosa.

No. 461] NORTH AMERICAN INVERTEBRATES. 305

Posterior eye-row not broader than anterior row; P. S. E. plainly

larger than P. M. E. ; head narrow . i ; " ‘ . Callilepis.

—Drassidæ ; face, aree

rax, zung and spinne

3. No dorsal groove; posterior eye-row "n recurved ; cephalothorax:

reddish yellow . Sergiolus.

Dorsal groove present, posterior were relly recurve E 4-

4. P. M. E. much nearer to P. S. E. than to each other; taphalodbofax and

abdomen bivittate . Cesonia.

. M. E. as near each ober as to ip s. E, or at ileus abdomen not

bivittate .

5. Upper ipsun plaisir TE a Pubs die iovis pair ;

large dark-colored species; tarsi and metatarsi I, II, and III heavily

scopulate à . Teminius.

Upper opinna. not TE iuo jaintéd n not longer than lower

pair n'a,

6. Posteridt eye-row slightly "owtdi P. M. E. widely ER no spine

above on base of tibie III and IV . : uh

Posterior eye-row straight or pocu

7. Posterior eye-row plainly broader than anterior row; P. S. E. betily; if

any, larger than P. M. E.; S. E. more than diameter apart

Poecilochroa.

Posterior eye-row barely longer than anterior row ; P. S. E. much

larger than P. M. E.; S. E. not diameter apart ; smaller spiders Eilica.

8. Posterior eye-row plainly procurved, P. M. E. oval

Posterior Iosue little if at all ee and a barely longer

than anterior row

9. Posterior Naas longor Mas miid row ; P. M. E. EN ssl

larger than P. S. E: 5 s Megamyrmecion.

Posterior row plainly longer than anterior row; P. M.

widely separate . : * C OH

10. Two spines soie on ibis Im and Iv Ux Drassodes.

306 THE AMERICAN NATURALIST. (VoL. XXXIX.

No spines above on tibie III and IV . ; . Drassus.

11. P. M. E. large, oval, contiguous or nearly so ; no spine übe on base

of tibia III and IV; usually with but one or two spines below tibia I

Zelotes.

P. M. E. smaller, nearly round, and plainly separate ; a spine above on

base of tibiae III and IV ; usually four to six spines below tibia I

Herpyllus.

P. M. E. smaller, oval, well separated; no spines above on base of

tibie III and IV; ten spines below on tibia I : i Drassinella.

Fic, 8.— Clubionidz ; Aa cephalothorax, mouth-

parts, and spinner

CLUBIONIDE.

1. On the venter there is a transverse furrow, remote from spindi rep-

resenting the openings of the posterior spiracles 10

No such furrow remote from spinnerets 2.

2. Two rows of nr spines under tibiz I iod. II, more dan two in | each

row. 11.

Not more iun 2-2 spines vider tibiae I PN II, or be impulit situ-

ate, and banded legs

3. Maxillz impressed wich an oblique fand; as in the Biossidas no dorsal

groove . . Micaria.

Maxillz without canon, convex ; deni groove ata present . 4.

4. Leg I plainly longer than IV ; body and legs pale; spines on legs

Chiracanthium.

Leg I not longer than IV ; . :

5. No spines on legs, or only a few dudo ‘tibia. t : : = &

Spines fairly numerous on legs à 3 . - à ;

6. Posterior eye-row strongly recurved . i à ; Trachelas.

Hte eyerow straight . eriola.

7. A. M. E. several times their diner kom bined aid often a

Sale spot near base of abdomen ; legs usually partly dark Castaniera.

A. M. E. scarcely diameter from es margin, no horny spot on

abdomen, legs never dark i

8. Lip longer than wide ; inne Map: : ee not mottled.

Clubiona.

No. 4651] NORTH AMERICAN INVERTEBRATES. 307

Lip broader than long ; cephalothorax mottled with brown . Pins

g. Anterior eye-row procurved . ; à ; ; : . Agroeca.

Anterior eye-row recurved . Hilke.

10. The furrow at or before middle e venter ; A. M. E. MN to A. S. E.

Anyphena.

The furrow behind the middle of venter; A. M. E. smaller than A. S. E.

Gayenna.

11. Sternum broad, prolonged between hind coxa; posterior eye-row not

recurved, tibia I with five or six pairs of spines below . Phrurolithus.

Sternum not ieu between hind coxa which are — contigu-

ous .

12. aerias eye-row slightly RER ive pairs ut spines under tibia I

Chemmis.

Posterior eye-row recurved . 13

13. But 3-3 spines under tibia I; two um o" on u bie I and Iv

Syspira

At least 5-5 spines under tibia I ‘ 14.

14. Eyes subequal in size ; anterior ción nete. ‘ iscrinihdes:

Eyes unequal in size; anterior eye-row not recurv rved

15. A. M. E. smaller than A. S. E.; posterior row weakly a

Apostenus.

A. M. E. larger than A. S. E.; posterior eye-row strongly recurved

Zor

Fic. 9.— Venter of Fic. 10.—Agalenidz ; face, cephalo-

Anyphzna. thorax, and spinnerets.

AGALENIDE.

1. Spinnerets arranged in one nearly straight transverse TOW Hahnia.

Spinnerets close together, in two rows Aic 2.

2. But six eyes, the A. M. E. lacking . Chorizomma.

With eight eyes

3- Both eye-rows very Ko procurv

form a nearly aba line with the P. S. E. ;

front

=, DNUS so lar a A M. E.

; Ber narrow in

. . Agalena

308 THE AMERICAN NATURALIST. | [Vor. XXXIX.

Both eye-rows not so strongly procurved 4.

4. A. M. E. much larger than any other eyes ; ol of M. E. as

broad below as above . Coras.

A. M. E. not larger than adir eyes; EE EN usually narrower in

front: .. 5.

5. Upper BEER of Make one joint audi not longt than Mawit pair; pos-

terior eye-row straight or even a little recurved ; tarsi I plainly more than

one half as long as metatarsus ; mandibles geniculate at base a.

Upper spinnerets of two joints and longer than lower pair

6. Basal spine on outer side under tibie I and II not Memor to next

prend larger spiders .

asal spine on outer side dida tibiæ I and: II reaching to next spine;

sen spiders

7. Mandibles plainly genitanti: at RE iis jus adis 1 , caiie

Mandibles not or barely geniculate at base ; legs very slender

Tegenaria.

8. P. M. E. situated fully their diameter apart . . Cicurina.

P. M. E. less than diameter apart, and closer to the 3: E. Cryphoca.

Fic. i1. Mna of

Fic. 12 —Theridiidz ; face and cepha-

Hahni

loth

THERIDIIDE.

1. Abdomen with hard skin and furnished with several humps ; small spe-

cies ; sternum truncate behind ; . Ulesanis.

Abdomen without humps and skin un : i : ; (o b

2. S. E. widely separate ; posterior eye-row recurved . ; . tr

S. E. contiguous or nearly so "

3. Leg IV as long as I; abdomen hr fat, and brósi bie: Epesinus.

Leg I longer than IV; abdomen globose . . Lathrodectus.

4. P. M. E. fully four times = diameter apart ; abdome prolonged

behind ; leg IV about as longas I . : š Spintharus.

P. M. E. rarely over twice M ein ‘ 3:

5. A. M. E.larger than P. M. E. and much wider ua dyp rather

high and concave; legs short, 1V often as en as I; palpi thick in

female 6.

A. M. E. rarely lager than P. M. Ex if so (hen not wider apart Au

6. Abdomen pointed behind and a flat : . Euryopis.

Abdomen more globose, broadly rounded bead o Dipena.

No. 461] NORTH AMERICAN INVERTEBRATES. 309

7. Cephalothorax with a transverse furrow in the middle ; abdomen usually

produced above behind, no chitinous pieces at base; u I net than

Copkidolhorax B adis ihe ordinary dorsal groove or impression ;

abdomen not prolonged behind ý 9.

8. Abdomen very long and slender, vérmior . ; ; “Atain,

Abdomen much shorter Argyrodes.

9. On that part of the RER that deiade the cephalothorax there is

a chitinous curved piece each side, in the female not prominent, in the

male much more so (they form a stridulating organ); colulus present.

Leg I usually but little longer than IV; femur I rarely more than one and

one fourth length of cephalothorax’; leg IV usually longer than II . 1o.

No such pieces on base of abdomen, colulus absent ; leg I much longer

than 1V, which is often shorter than II; femur I u: one and one

half to twice the length of cephalothorax ve ag:

10. Sternum broadly truncate between coxa IV; saisi species

Crustulina.

Sternum pointed behind ; coxa IV closer together

11. S. E. slightly, but distinctly separate, lower eye-row nearly straight ;

P. M. E. not large, and rather widely separate . Lithyphantes.

S. E. contiguous . 12.

12. P. M. E. plainly larger dan K M. E. 3 j abdoingi not black, with two

yellow spots . A SUPE

P. M. E. not Ir ia‘ M. E. : : : : ; se P a

13. Leg IV a little longer than I, all short ; . Pedanostethus.

Leg 1V plainly shorter than 1, both long and desde À . Teutana,

14. A. M. E. much larger than A. S. E.; leg I longer than IV . Steatoda.

A. M. E. not larger than A. S. E.

15. Leg IV plainly longer than I; sternum granit i i / Asia.

Leg I a trifle longer than IV . 16.

16. Femur I not one and one fourth as liri as cione | idol

Enoplognatha.

rather depressed .

Femur I nearly twice as kk as cephalothorax abdomen more slender,

and in male, constricted near middle Coleosoma.

17. Sternum truncate between hind coxe ; aria dae with few or no

teeth ; leg I not much longer than IV : 18.

Samen pointed behind; hind coxa more re ws claws

pectinate ; abdomen usually globose ; leg I often much longer than IV

a3:

18. No shields or sigille on ipe iN i ; ; ; ; ; T9:

Shields or sigilla on abdom 21.

19. Abdomen globose ; ehe short and high, narrow in front 20.

Abdomen elongate ; cephalothorax broad in front ; legs banded

Ceratinops.!

1 Ceratinops, new genus for Ceratinella annulipes Banks.

310 THE AMERICAN NATURALIST. (VoL. XXXIX.

20. Tibia I not as long as cephalothorax ; "o THU very broad ; male

eyes elevate Microdipoena.

Tibia I longer shan cephalotorax dich is more mat than pre-

ceding . : ; : : Mysmena.

21. Abdomen with skied across AN : : ; : . Idionella.

Shield not across base ; 24.

22. Abdomen of both sexes with asia didit: aae viti hori fron eye-

region ; no stiff bristles under femur I . istiagonia.

Abdomen of female without dorsal shield, pnl Kt; male without

frontal horn; a row of stiff bristles under femur 1. . Ancylorrhanis.

23. Anterior eye-row procurved ; tibia of male palpus large; nn with

abdomen swollen in middle each side Theridula.

Anterior eye-row straight or RN tibia of tial palpus not

enlarged ; female not with swollen sides 3 : x Theridium.

LINYPHIIDA.

1. Cave spiders ; no claw at tip of pens of female . ; : eT

Not cave spiders ; ‘ x cota

2. Without eyes ; sternum e : . i 7 ; . Antrobia.

With eyes . : UR T

3. P. M. E. about as ug BM to P. S E. as to pars nies yt M. E. barely

diameter apart . Phanetta.

P. M. E. much coser to b du other thao to P. S. E; A. M. E. several

diameters apart . _ Troglohyphantes.

4. No claw to tarsus * femads "aue ; epigynum without a finger or hook ;

male palpus with a tibial apophysis, a but one spine above on tibia

IV : (Erigoninz) 16.

Kd to pinu. in deside ; epigynum with a finger or hook ; male

palpus without a tibial apophysis, although sometimes enlarged or a tooth

at tip; usually two spines or erect bristles above on tibia IV

(Linyphine) 5.

5. Legs without spines ; mandibles long, and their lower anterior border

provided with several long, slender teeth; A. M. E. larger than P. M. E.

Tapinopa.

Legs with at least a few spines, or not agreeing with above 6.

6. Mandibles long, slender, divergent, in front with 3 pairs of long spines,

abdomen depressed and rather broad; P. M. E. less than diameter apart

Drapetisca.

Mandibles without the 3 pairs of spines in front 5

7. Tibiz without lateral spines: metatarsus I not longer ihan tibia I;

usually small spiders

Tibiæ with lateral spines ; metatarsus I usually as dong as, often longer

than, tibia 1; larger spiders . : : 7

Na. 461.) NORTH AMERICAN INVERTEBRATES. 311

8. Posterior eyes closer together; S. E. on gain tubercles ; legs long and

very slender . Microneta.

Posterior eyes fanis apart; S. E. not on hedo legs less slender

Tmeticus.

9. P. M. E. plainly closer to P. S. E. than to each other, and larger than

S. E.; femora with few if any spines . . Neriene.

P. M. E. not closer to P. S. E. than to ide other

Io. No spines on metatarsi; P. M. E. rather close ne

TEMA

Spines on metatarsi, at least one a1.

11. P. M. E. very much larger than S. E. two or Ei times linee about

one diameter apart, and as far from very small S. E., which are no larger

than A. M. E. ; abdomen slender . ; \ i . Linyphiella.

P. M. E. not much larger than other eyes . |j Ir

12. P. M. E. at least two diameters apart,or else gis daxthes ira S. E.

than from each other; — of M. E. plainly wider above than

below . . Linyphia.

P. M. E. scarcely more dua diaiuster e and about as close to P.

S. E. : ER E ts.

13. All REN with some distinct spines. : : i . hog P

All femora not with distinct spines . : ; ; i WE T

14. Tarsus I two thirds of metatarsus I; quadrangle of M.E. rather nar-

rower below . . Bolyphantes.

Tarsus I only one ali: of metatarsus © quadrangle of M. E. as wide

below as above Labulla.

15. Abdomen high uid bres at Jun. Berne to a init behind

epthyphantes.

Abdomen elliptical or even broader beyond middle, not tapering behind

Frontinella.

16. Tarsus I io! about one half as long as metatarsus I, male with lobate

. Hypselistes.

Tarsus I two j thirds or more iol length " he metatarsus I . 17.

17.2 Dorsum of male abdomen with a corneous shield ; often present also

in female i = 18.

Dorsum of abdome in Lon sexes en shie ld 20.

18. Sternum broadly truncate and slightly concave behind between hind

coxz; usually some corneous pen on venter ; tarsi I but little shorter

than metatarsi I ; Ceratinella.

Sternum less broad and FERN convex behind Daaa hind coxe ;

no corneous pieces on venter . 19.

apa Tarsi I plainly shorter than metatarsi ; no bole à in ide of eli head ;

P. M. E. but little higher than A. M. E. : . Exechophysis.

! Linyphiella, new genus for Linyphia coccinea Hent ;

* Beyond this the table is based on males, although da will frequently run

to proper place.

312 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

Tarsi I about as long as metatarsi ; a hole in side of head of male;

P. M. E. much higher than A. M. E. Lophocarenum.

20. Head of male with a horn from tidddle he eye-region ; sternum rather

Re! posterior eye-row strongly procurved : . . Cornicularia.

He male without such horn ; sternum often broad, triangular 21.

21. Head s male plainly lobed, or at least with a hole in side behind S. E.

23:

Head of male not lobed, nor with a hole in side à i e

22. Metatarsus I of male swollen in middle š i 3 Caracladus.

Metatarsus I normal 13.

23. Male with two large and two ahad tufts of bristles in i ilddie of eye-

region ; posterior eye-row very strongly procurved . Panamonops.

e without such tufts ; posterior eye-row but little procurved 24.

24. P. M. E. situate upon top of lobe of male : 25.

Lobe of male not bearing eyes . j 5 Dismodicus.

25. Sternum broad, triangular . i 1 ^ i . Diplocephalus.

Sternum more slender à . Walckenzra.

26. Male having a horn from middle at pins: ; . Delorrhipis.

Male without such horn 27.

27. Male palpus with enlarged Sanur; hed T abe suvaied: plistedor

eye-row slightly recurved ; legs slender . ; : . Gonatium.

Male palpus with femur normal . 28.

28. A projection below at tip of tibia of: malè jipii sides ist odpinib:

thorax often with teeth ; posterior eye-row slightly recurved . Erigone.

No such projection to tibia of male palpus . 2

29. S. E. situate on a slight elevation, making ead broad in fronts

sternum rather broadly truncate behind between hind coxe; tibia I

shorter than the cephalothorax 3”

S. E. not on elevation ; sternum narrowly, if at all, produced between

hind coxz ; 31.

30. Two rows of spines pales | metatarsus IV; mere with face intita

spines under tibiæ and metatarsi 1 and II Maso.

No rows of spines under metatarsus IV, nor eie tibia "n metatarsi

I and 1I . . Ceratinopsis.

31. Tibia I bare iin een — very TOTEM sternum nar-

rowly truncate between hind coxa; head of male elevated — Notionella.!

Tibia I shorter than cephalothorax . ie

32. Two rows of spines under tibiae and metatarsi I aid H Satilatlas.

No such spines under these joints ; : 3$

33. P. M. E. closer to each other than to P. s. E.; a hump behind eye-

region in male Grammonota.

Eyes of posterior row abéut equidistant ; no Bady behind eye-

region ‘ : à i 3

! Notionella, new genus for Ceratinopsis interpres.

N0.461.] NORTH AMERICAN INVERTEBRATES. 313

34. Distance between eyes of posterior row not much greater than

diameter of an eye

35:

Distance between eyes a jorni row more han two y dinata of an

eye : : í : Acartauchenius.

35. Head af hale slevated i ; : Tiso

Head of male not elevated . i : i t Gongirdium.

MIMETIDE.

Clypeus lower than ocular area ; hind legs much shorter than front legs ;

lip much longer than broa Mimetus.

Clypeus as high as ocular area; hind legs not noch shorter than front

legs ; lip but little longer than broad ; i à : . Ero.

Fic. 13.— Cephalotho- Fic. 14.— Cephalotho- Fic. 15.— Dictynide; face and

of Cornicularia. rax of Diplocephalus. cephalothorax.

DICTYNIDE.

t. Legs vihant nn cribellum usually undivided in middle by a

ine nS

Legs with spines ; aie divided a a ine, Tivos very low 2.

Titan

2. Maxillz inclined over the lip ; hind legs TS. É ceca.

Maxille straight; hind legs with spines . . Amaurobius.

3. With but six eyes; colors pale . . . Neophanes.

With eight eyes, but A. M. E. are sometimes dee small iu x

4. Cribellum divided by a line in middle ; a Dictynina.

Cribellum undivided . ‘ ; ; Sta M

5. A. M. E. very minute : ; : ; ; : cob

A. M. E. subequal to others RE t rh LUDUM

6. A. M. E. higher than A. S. E. . : ; : i Dictyolathys.

A. M. E. between A. S. E. ma d uL ups Prodalia.

7. Lip one third shorter than maxille . . . >. > Lathys.

Lip nearly as long as maxille . . . . . . Dictyna.

DINOPIDJE.

We have but one genus, Dinopis, in this country, with one species; a

long and slender spider, not common throughout the ripe States.

314 THE AMERICAN NATURALIST. | [Vor. XXXIX.

ULOBORIDE.

All eyes subequal in size, cephalothorax more elongate . Uloborus.

Eyes of posterior row very much larger than those of anterior row, in

fact the A. S. E. are almost invisible : à i . Hyptiotes.

EPEIRIDE.

1. Mandibles large, edd divergent, abdomen and legs more or less

elongate 1 . Tetragnathine.

Mandibles eei vi not strongly yet. cde : . Epeirina.

Fic, 16.— Cephalothorax of Fic. 17.— Epeiridz ; cephalothorax, face,

Tetragnatha. and spinnerets.

Tetragnathinie.

1. Abdomen with a transverse,ventral furrow near middle ; abdomen not

twice as long as broad . ; : : : - Gi pe gm

Abdomen without such hoy

2. Abdomen not twice (or d as lag as SEEN not inch longs u

cephalothorax . . . Pachygnatha.

Abdomen three or dou times as bug as broad . . vA)

3. S. E. as close or closer than M. E. ; j . Tetragnatha.

S. E. farther apart than M. E. . . . i i

4. Abdomen projecting beyond ipbitiecete: inatail . . Eucta.

Abdomen not projecting beyond spinnerets in a distinct tail

Eugnatha.

Epetrine.

1. Abdomen with a horny shield, or at least with sigiflce | "d IV M.

than I

Abdomen without shield or us: i IV hona than b (P

2. Spinnerets enclosed at base by a horny ring; abdomen with spines 3-

Spinnerets not enclosed by horny ring ; abdomen without, spines

Cercidia.

No. 461] NORTH AMERICAN INVERTEBRATES. 315

3. Cephalothorax as broad as long; abdomen broader than lon

Gasteracantha.

Cephalothorax and abdomen longer than broad . Acrosoma.

4. Cephalothorax bearing spines or tubercles . j à cive

Cephalothorax without spines or tubercles . $.

5. Posterior eye-row strongly procurved ; metatarsus pss tarsus 1 plainly

longer than tibia plus patella I ; cephalothorax rather flat j

Posterior eye-row barely, if at all, procurved . ; : ; Jy

6. A. M. E. nearer to each other than to A. S. E., large species

Argiope.

A. M. E. as near to A. S. E. as to each other; small species Gea.

7. All metatarsi longer than tibia plus patella; abdomen subcylindric ;

maxille longer than broad; S. E. separate by fully two diameters ; legs

often with bands of erect hair . . Nephila.

Metatarsi shorter than tibia pita yeiellas pedis. "n in fore legs;

when so, then maxille shorter than broad, S. E. approximate, and no

bands of erect hair on legs 8.

8. Hind femora with a fringe of coc iib at bins ibdomés babicylin-

dric; S. E. approximate; P. M. E. only about twice as far from P. S. E.

as from each other; legs very slender and with only a few slender spines

Leucauge.

Hind femora without such fringe of erect, curving hairs at base 9.

9. Cephalothorax much elevated behind, sloping forward to re 10.

ephalothorax not prominently elevated behind . Il.

10. Legs with long spines; P. M. E. less than diameter pet: no tüber-

cles on abdomen . . Mangora.

Legs without spines, or very Dm ones ; P. M. E. fully two diameters

apart; abdomen with tubercles Carepalxis.

nn. omen with a median hump or cone at india as wal as lateral pro-

jections ; sternum rather long; clypeus high . à : . Plectana.

Abdomen without median together with lateral projections . CO.

12. S. E. separated by fully diameter and on separate tubercles = 44.

S. E. contiguous or nearly so, at least upon the same eminence . 14.

13. P. M. E. small and close together; mandibles slender

Dolichognatha.

P. M. E. equal to others and widely separate . Azilia.

14. P. M. E. scarcely more than one and a half Möhieter apiri, and as

close to the P. S. E. as to each other ; S. E. — separate ; all y

subequal in size ; epigynum without a finger .

M. E. much closer to each other than to P. S. E : "4

15. Tarsus IV with many serrated bristles beneath; di spider with

globose abdomen . Theridiosoma.

Tarsus IV RER re bieten biu larger species ; een

not globose ,

3 16 THE AMERICAN NATURALIST. [VoL XXXIX.

16. Maxilla twice as 2 as broad; mandibles long and slender ; abdomen

convex above . ; i : j Meta.

Maxillz not twice as ido as Hac à EN, s?

17. Abdomen elliptical, rather depressed, ion hate at Else Zilla.

Abdomen subcylindric, with two ip humps at base . . Hentzia.

18. No spines above on tibize I and I À . 1- Mk

With some spines, at least one, vis on tibiæ I and II i piod.

19. Abdomen with spines or humps; Mte broad and tumid in

front i . Wagneriana.

Abdomen without spines or hips etazygia.

20. Legs very slender, especially leg I, ilio desinis of spines;

cephalothorax very slender ; posterior eye-row strongly recurved

Acacesia.

Legs less slender and with a number of distinct "rM or else the pos-

terior eye-row not strongly recurved : . 21.

21. Abdomen pointed at base, elongate, sternum one and: one half longer

than broad; P. M. E. scarcely diameter apart ; . Larinia.

Abdon not pointed in middle at base . 22.

22. Abdomen as high behind middle as at base, and elliptical in 1 outing or

broader behind middle ; P. M. E. about diameter apart; epigynum with-

out finger; small species, with short legs Singa.

Abdomen highest toward base, and usually "MESS near bos geo

23. Cephalothorax with a broad transverse furrow (at least in female);

abdomen usually prolonged above behind; A. S. E. never twice as far

from A. M. E. as latter from each other ; quadrangle of M. E. plainly

wider below than above ; legs more hairy . Cyclosa.

Cephalothorax without such furrow; abdomen binds prolonged above

behind ; legs more spiny i ; : i . Epeira.

Fig. 18.27 homisidz; face, cephalothorax, Fic. 19. — Cephalo-

and spinnerets. thorax of Pisaurina.

THOMISIDE.

I. Legs III and IV not or scarcely shorter than legs I and II; tarsi I and

II scopulate M least in er hairs of ind usually branched, prone

nor erect . (Philodromine) 2.

No. 461.) NORTH AMERICAN INVERTEBRATES. 317

Legs III and IV much smaller than I and II; tarsi I and Il not

voip ; hairs of body, simple, scattered, and erect. (Misumenin®) 7.

2. Leg II very much longer than I; posterior eye-row almost straight ;

cephalothorax broad Ebo.

Leg II but little ione vidt 1; josteta eye-row very vüdoby recurved

3. Five pairs of spines under tibia I and II; P. M. E. nearer to P. S. E.

than to each other . i Philodromoides.

Less than 5-5 spines de tibiæ 1 adl Huc i . : ch.

4. P. M. E. farther apart than from P. S. E. ; abdomen not very slender ;

leg IV shorter than leg I . Philodromus.

P. M. E. not nearer P. S. E. din to sach other! or if barely so then

leg IV is longer than I 5.

. M. E. much nearer to iib itus "im io. p. s. E. ; BR long

xii weg leg IV longer than I. ; . Tibellus.

. about as near P. S. E. as to iai other 4 ; 2

6. Leg IV ea than leg I . ; ; : : i en

Leg IV longer than leg I . Thanatus..

7. Legs I and II with spines only det bie and metatarsi, at most with

one or two very minute ones elsewhere. . 3 i 8

Legs I and II with distinct spines diciliee à 10.

8. Abdomen furnished behind with two prominent denken seoiaclions

Thomi

Abdomen without two projections behind ; DK

9. A ridge between eyerows . : i : ; ; . Runcinia.

No ridge between eye-rows Misumena.

10. Abdomen high and pointed behind; clypeus eg: : tüberde at P. S.

E. much larger than at A. . Tmarus.

Abdomen broadly rounded tehtid dida more vati; tubercles of

S. E. subequal in sizè . ; : DIS

11. Cephalothorax very flat ; di cultus seein : : Coriarachne.

Cephalothorax moderately high

12. Abdomen, cephalothorax, and lies pale whitish or i yali, but little

marked except bands on legs of males Misumessus.

e t or cephalothorax and legs, ek, or heavily marked with

‘>

13. Quia a M. E. higher ihan brad: bise I We II with 2-2

spine zyptila.

Dini a M. * not bigher than wi : iR

14. Eyes of lower row equidistant; A. M. E. larger than P. M. E. ; tibie

I and II with 3-3 spines . | Syren.

A. M. E. nearer to A. S. E. han to cach abe, not larger than

P. M. E. ; tibia I and II with 4-4 or 5-5 spines . ; . Xysticus.

318 THE AMERICAN NATURALIST. [Vor. XXXIX.

SPARASSIDE.

1. P. S. E. in a row with anterigr eyes; tarsal claws smooth; cephalo-

thorax Wr flat à . Selenops.

. behind anterior row; tarsal dies töbet ; cephalothorax

plainly ea i ; - M

P. S. E. much ho en P. M. E. : . Heteropoda.

P. S. E. barely, if at dens larger than P. M. E. ; : : Olios.

PISAURIDE.

Anterior eye-row recurved ; quadrangle of M. E. broader behind than

high ; clypeus about as high as quadrangle of M. E. R Dolomedes.

Anterior eye-row straight; quadrangle of M. E. not broader behind

than high ; clypeus not as high as quadrangle of M. E. . . Pisaurina.

PODOPHTHALMIDE.

Area outlined by four anterior eyes is much wider than long

Thanatidius.

Area outlined by four anterior eyes is as long as wide Maypacius.

CTENIDE.

A. S. E. nearer to A. M. E. than to either P. S. E. or P. M. E.

Titiotus.

A. S. E. nearer to P. M. E. or to P. S. E. than to A. M. E. Ctenus.l

LYCOSIDÆ.

FiG. 20.— Lycosidz ; Mm cephalotho- Fic. 2:.— Oxyopidz ; face and

rax, and spinnerets diui thorax.

l This includes Cupiennius and Anahita ; they differ from Ctenus only =

minute or slight characters difficult of verification. Titiotus is unknown to me

No. 461.) NORTH AMERICAN INVERTEBRATES. 319

ı. Tibia III and IV with a stout spine at base above .

Tibiz III and IV without spine at base above, although there may A

one near middle above en

2. No spines above on tibize U1 sad IV; led bel above on sone NM

head large and high .

A spine r near middle s Sie on bie 1H ai Iv $:

3. Upper spir ts not longer than lower ; anterior eye-row not videt than

the second . . Trochosa.

Upper spindeners we iin Met; anterior ede wider than sec-

ond row ; tarsi heavily scopulate à . Sosippus.

4. Cephalic region with a wedge- PON ink; ARE a central stripe ;

posterior spinnerets longer than others ; eyes of second row scarcely their

diameter apart, small species ^ ; i i à ; . Pirata.

No such mark on cephalic region ; spinnerets subequal in length E;

5. Tibia I with 4—4 imbricated spines, the basal ones reaching beyond

base of second ones ae very small species; eyes of second row

not their diameter apart Trabea.

Basal spines on tibia I not reaching beyond base di the third pair,

usually but 3-3 spines below 6.

6. oe without median pui of any ied: ; spines adie tibia I

very short, 3-3 . Allocosa.

xeolycos

eter apart; 3-3 long spines under tibia I, the basal pair usually reaching

next pair; lip not longer than broad ; smaller spiders . . Pardosa.

OXYOPIDÆ.

1. Posterior eye-row only slightly procurved ; mandibles higher than

height of cephalothorax in front; large greenish spiders . Peucetia.

Posterior eye-row strongly procurved ; mandibles ac as long as

height of cephalothorax in front 2.

2. P. M. E. much closer to P. S. E. ihe to sadi oer : Api.

P. M. E. about as close to each other as to P. S. E. . . Oxyopes.

ATTIDJE.

1. Abdomen more or less constricted ; cephalothorax usually constricted ;

pedicel distinctly chitinized . er i 2.

Neither cephalothorax nor abdomen ie: pedicel soft . 4.

320 THE AMERICAN NATURALIST. [Vor. XXXIX.

2. Leg I plainly thicker than the other u cephalothorax (gue slightly

constricted . Peckhamia.

Leg I as dente as Giorn ; ; : : i i s 3.

Fic, 22.— Attide; vu. cephalo- Fic. 23. — Attide ; two types of

thorax, and spinnerets. spine-arrangement under tibia I.

3. Cephalothorax and abdomen very strongly constricted ; apical joints of

female palpus slender . : Synemosyna.

Cephalothorax and abdomen but little ansehe apical joints of

female palpus enlarge ; i . Myrmarachne.

4. Eyes in four rows ; ede green spiders x bog Fantasia

Eyes in three rows . i

5. No spines under tibia I, or at most tq one or two iati ones 6.

Several spines under tibia 9.

6. Cephalic part very long, reaching ‘tact to bébé ot adohi; leg I

plainly thickened : Homalattus.

ephalothorax ones bid helo middle to bal A ; : 7.

7. Leg I plainly heavier than others 4 : : : .

Leg I slender, as the others . F : : : i Salticus.!

8. No spines on hind legs . : \ i ; i . Admestina.

A few distinct spines on hind le i . Eremattus.

9. Leg III as long as or longer than IV, at least | in males; usually spines

on sides of patellæ III and IV ; coxæ I separate by more than width of

lip; 2-2 or 3-3 spines under tibia I; legs usually quite hairy . 3%

Leg III plainly shorter than IV Lid

10. Ocular area occupying fully one half of the RN 9 the dorsal

eyes situated at its greatest width, and projecting laterally

Zygoballus.

. Ocular area occupying less than one half of the cephalothorax ; or if

so, then the STN is not plainly broader at dorsal eyes than else-

where . i . H.

11. Tibia I with 4—4 spines below (or leas), the base one sofi inner series is

nearer to base than the first third of tibial length :

! Latreille in 1810 fixed type of this genus as S. scenicus.

No. 461] NORTH AMERICAN INVERTEBRATES. 321

Tibia I with 3-3 spines (or less), the basal one of inner series situate

one third of tibial length (or greater suse from base; coxa I usually

widely separate . ; i 42.

12. Metatarsus IV heavily igit d near base and middle, both below and

on sides; cephalothorax never very low, nor very broad ; ar spines

on patelle III and I

Metatarsus IV spined only at tip, or "with one or two sieh spines on

sides; never a basal and middle circle of spine s.

13. Coxe I approximate; leg I plainly dickendd: sternum usually long ;

usually large species 1 15.

Coxe I widely xn: fu I ‘barely dele ened sternum short; very

small species, with a narrower cephalothorax 14.

14. Ocular area occupying nearly one half of bepiodpttóters as wide i in

front as behind, dorsal eyes as large as laterals of first row ; no spines

below on tarsus IV. eon.

Ocular area less than one half of euplalo gota, rather wider behind ;

dorsal eyes smaller than laterals of first row ; spines below on tarsus IV

Attidops.

15. Abdomen about four times as = as broad; tibia I with 4-4 spines

below . $ i ; i en

16.

Abdomen ndi shortit

16. Eye-region occupying two “fifths of Kepler the sternum nearly

as broad as long, smaller species Fuentes.

Eye-region occupies about one third of cephalothorax the sternum

much longer than broad ; larger species : ——

17. Tibia I with 4-4 spines below

Tibia I with less than 4-4 spines buius 19.

18. Ocular area N narrower behind die in p nh: lc IV plainly

Mevia.

longer than I

Plexippus.

Ocular area barely narrower behind; ‘les I as long as IV

19. Cephalothorax rather prd N occupying "€ one third 2

length; tibia I with 3-3 spine

Cephalothorax p gea ai fully two fifths ot ed;

coxa I widely separa

20. Basal spine of ipa I saa IV

abdomen vittate

Basal spine of tau Hl and Iv biuch denkt; abd

about: one half as ong as the joint ;

Phlegra.

omen not vittate

* Sidusa.

21. Patella III as long as IV, no patellar spines e

Patella III shorter than IV, patellar spines pres "s.

22. Cephalic part about two thirds of cane reaching almost to

I thickened ; hind metatarsi spined only at tip

abdomen ; legs short, leg I thi mn

1 Attidops, a new genus for Ballus youngi Peck.

322 THE AMERICAN NATURALIST. (VoL. XXXIX.

Cephalic part far shorter . 23

23. Cephalothorax high, and rather bisd; diadranghé of eyes wider

behind than in front; large species, rarely under 7 mm. ; leg I heavy and

very hairy, often with fringes of hair, mandibles often FERN often

a group of stout bristles near lateral eyes . ; idippus.

Cephalothorax not as high and heavy, leg I not so babes smaller spe-

cies, rarely over 6 mm. 24.

24. A spine above before middle on | tibia Ill aod IV, a on base

of metatarsus IV ; leg I not thickened ; small species . Attinella.1

No spines TNR on tibia III and IV, nor on base of metatarsus IV 25.

25. Tibia I with 2-2 large spines, and toward base are two pairs of large

bristles with enlarged bases, not obscured by other hairs ; metatarsi IV

spined throughout, patella III and IV with spines; leg I not much

thickened . Thiodina.

Tibia I vibe such bites, distinct bois all die 3-3 spines below

26.

26. Legs with few hairs (except sometimes a brush under tibia I in male),

tibia I about three times as Nes as broad, with very small spines ; legs

lineate with dark . Tutelina.

Legs more hairy, tibia ] eie stouter ; leo not neste joe rarely) with

27: Cipto eee nn dink width of dorsal eye-line ; tibia and

metatarsus I in male elongate; abdomen quite slender; s I not very

heavy ; legs III and IV not plainly banded

m narrower at dorsal eyes; tibia and; metatarsus I not

elongate in m

28. n iun depressed ~ I very uch thickened, mali with

horny shield on base of abdom : . Metacyrba.

Cephalothorax higher ; pray vitu shield at base ; 49g.

29. Tibia I plainly convex below ; legs less hairy ; cenlialouaaes ipods

Tibia I barely convex below ; legs more hairy ; cephalothorax Bes

Dendryphantes.

30. Very few spines on hind legs, none above on bases of tibia III or IV,

nor on base above of metatarsus III; quadrangle of eyes wider in

front ; smaller, less hairy species : Habrocestum.

Hind legs with many spines, alten. one above on base of either tibia

III or IV or both, and a spine above on metatarsus III; of

eyes usually wider behind . : ; Pellenes.

' Attinella, a new genus for Aztus dorsatus Banks.

Includes Evarcha Simon ; our one species (which seems to be the same as the

E. AY of A UM cannot be readily separated by generic characters from

some Pelle

No.461] NORTH AMERICAN INVERTEBRATES. ` 323

PAPERS ON CLASSIFICATION OF AMERICAN SPIDERS.

BANKS, N.

'92. A Classification of the North American Spiders. Can. Entom.,

vol. 24, pp. 88-98.

CAMBRIDGE, F. O. P.

'97-:05. Arachnida-Araneida, vol. 2.

London.

COMSTOCK; J. H.

A Classification of North American Spiders. Ithaca, N.N. 1

Biologia Centrali-Americana,

55 PP-

PECKHAM, G. W. and E. G.

'88. Attide of North America.

104 PP-

SIMON, E.

'97-:04. Histoire naturelle des araignées.

THORELL, T.

'69—70. On European Spiders. Upsala; 240 pp-

Trans. Wisc. Acad. Sci., vol. 7,

Paris ; 2d ed., 2 vols.

BIOLOGY OF ACMA TESTUDINALIS MULLER.

M. A. WILLCOX.

Acmea testudinalis Müller, the tortoise-shell limpet, as it is

called by Forbes and Hanley, is the common limpet of our New

England shores. It, together with its variety alveus, is the sole

representative on this coast not only of its genus and family but

of the entire group of the Docoglossa and by far the most con-

venient example of the suborder Diotocardia, which includes all

the more primitive Gasteropods. It is abundant and accessible,

itis easily kept alive in aquaria, and living as it often does in

tide-pools, is conveniently observed under its natural conditions.

But in spite of these facts it has never been made the subject

of careful study.

I am at present engaged upon a paper which is intended to

supply this lack and from which I excerpt the following biologi-

cal notes.

Acmeea is a large genus whose eighty-four species are widely

scattered over both northern and southern hemispheres. Repre-

sentatives have been recorded not only from both eastern and

western shores of all the great continents except Africa,! but

from Australia, from New Zealand, and from many islands of the

Atlantic and Pacific including some which are oceanic. The

genus is at present arranged only tentatively. “More than any

other shells, these must be studied with constant reference to

not only habitat geographically, but station as well. For an

exact knowledge of the group we must therefore wait until

observations on the species are made with special reference to

their modes of life and surroundings" (Pilsbry). It seems

probable, moreover, that a careful comparative study of the dif-

ferent species might throw light upon various questions of

geographical distribution. This statement of the final aim of

! Two species only are as yet recorded from this continent: one from Natai

and one from Cape Town.

325

326 THE AMERICAN NATURALIST. [Vor. XXXIX.

the investigation may serve to explain the presence in these

notes of material that might otherwise seem trivial. It is

believed that nothing has been admitted which does not bear on

the general question.

Limpets are found on the entire New England coast and

northward to the Arctic Ocean. Comparatively rare and local

south of Cape Cod, they increase in numbers and in size as one

passes northward until at Eastport, Maine, they are one of the

most abundant of thelittoral molluscs. They are found between

tide-marks in pools and also in such shaded places as provide

them at once with coolness and moisture. The vertical face of

a rock heavily hung witb dripping Fucus or the under surface of

the larger beach pebbles are attractive spots. Although they

are to be found occasionally where the water is at least slightly

fouled by sewage, as in the estuary at Beverly, they are far more

abundant in that which is clean and pure.

So far as reported they seem to reach their maximum size in

the region of Eastport, which is bathed by the cool waters of the

Arctic current. On the Massachusetts coast a limpet an inch

long is a giant but at Eastport they not rarely reach a length of

32 mm. The first explanation of this fact which presents itself

is of course that the cooler water presents the optimum temper-

ature for these animals; this is not, however, the only possible

explanation. The Arctic current is not only cooler but more

equable in temperature than more southern waters. At East-

port the maximum yearly variation in temperature of the water

is about 12° C. (32.5°-54° F.): at Boston it is nearly 23° C. (29°-

70 F.! Limpets living entirely below tide-mark would there-

fore enjoy comparatively equable temperature conditions at East-

port. This would not, however, be true for those living between

tide-marks, for the annual variation in temperature of the air at

Eastport is often as much as 35? C. (47-67? F.) — 10° C., it may

be,in a single month. Bathed twicea day by the water, exposed

twice a day to the air, such individuals in spite of the compara-

tively cool places which they affect, would be exposed to condi-

' These figures are deduced from the records of the U. S. Weather Bureau at

Eastport and Boston, for the years 1887-89, the only years during which ob-

servations of water temperature were made.

No. 461.] BIOLOGY OF ACM HA. 327

tions probably at least as variable as those of the Massachusetts

waters. lf now we examine their size with reference to their

habitat, we find that the limpets of Eastport are large only

when living at or near the low-water mark of spring tides so that

they are rarely or never left uncovered by the sea, and that

higher up on the beach the animals though no less abundant are

of smaller size, no larger in fact than with us. "We find also

that in Massachusetts there is no marked difference in size

between limpets which are continuously submerged and those

which live between tide-marks. The conclusion is therefore

forced upon us that size in these animals is correlated not neces-

sarily with a low but with an equable temperature. The advan-

tage of uniform thermal conditions was long ago pointed out by

Mobius and Semper.

In the late autumn, limpets in the neighborhood of Boston

either altogether disappear or become very scarce, reappearing

in numbers in March or April. In Eastport, however, they

remain near the shore for the entire year. Their disappearance

from the Massachusetts coast is probably due to a retirement

to deeper water; this is, I am told by Professor S. I. Smith, the

practice among several of our littoral animals. Limpets will

stand a good deal of cold; Miss Annie Sullivan, an observant

and intelligent collector who is familiar with the animals at East-

port, tells me that she has revived them after ice had formed

within the shell and found them apparently no worse for the

experience. It seems very probable therefore, that when they

withdraw in the autumn they go only a little below tide-mark,

thus avoiding the very considerable daily variation in tempera-

ture to which they would often be subjected if they remained

above the low-water line.

The distribution of limpets as given above is taken from

Smith and Verrill's * Invertebrate Animals of Vineyard Sound,"

a work which was published nearly thirty-five years ago. Iam

not aware that any investigations have been undertaken since

that time which would show whether it is still correct. Forbes

and Hanley described this species in 1853 as having, at least

in Great Britain and Ireland, a tendency to migrate southward

and Forbes had already described its sudden appearance nearly

328 THE AMERICAN NATURALIST. (VoL. XXXIX.

twenty years before on the northern shore of the Isle of Man,

where it is still to be found. In view of these facts it would be

very interesting to learn whether it is moving southward on our

own coast.

Distribution of the adult animal is probably effected not only

through its own locomotion but also by the aid of tides and cur-

rents. On one occasion, though only on one, I found a limpet

crawling back downward on the surface film like a fresh-water

snail but I have not very infrequently found them clinging to

floating pieces of the larger Floridie, upon which they feed. It

will be remembered that Nacella and Helcioniscus live habitu-

ally upon the large fronds of Macrocystis. © Occasional trans-

portation of the adult by such means may not impossibly be a

more effective factor in its distribution than the brief pelagic life

of the young, which Boutan found in the case of A. virginia to

be limited, at least in the waters of Roscoff, to a few days' dura-

tion.

Locomotion is almost exclusively effected by crawling over

the substratum. Progress is exceedingly slow ; the fastest crawl-

ing of which I have record was at the rate of about three inches

per minute. This was in a tide pool where the animal was un-

disturbed and in natural conditions. Under such circumstances

it often remains motionless for hours. In captivity it is not

unusual to find one limpet crawling over another or adhering

to its shell, although in such circumstances I have never

observed either individual showing any recognition of the pres-

ence of another of its own kind.

In view of the well known homing habits of Patella and of

the fact that I have found the same power possessed at least in

a limited degree by animals so widely separated as Fissurella

barbadensis Gmelin and Siphonaria alternata Say, I have made

repeated attempts to satisfy myself of its existence in Acmza.

These attempts have, however, been unsuccessful. The diffi-

culty lies in the character of the rocks of the New England

coast, which are unsuited either to the formation of a sunken

" scar" like that which indicates the home of Patella or of a dis-

colored spot like that produced by Siphonaria. It is therefore

impossible to locate with certainty the * home" of a limpet, which

No. 461.] BIOLOGY OF ACMAA. 329

is the first step in determining whether or not it possesses the

homing power. Dr.W. H. Dall, however, tells me that he has

observed on the Pacific coast individuals of Acmea spectrum

Reese whose shell margins exactly corresponded to the irregu-

larities of the soft rocks on which they live. Fisher notes that

both this and other species of Acmzea are often found adhering

to the shells of Lottia in which they have made shallow depres-

sions. These observations furnish the strongest presumptive

evidence that in some species, at all events, the homing power

is present and render desirable the investigation of the ques-

tion in Acmea testudinalis under conditions more favorable than

those afforded by the New England coast.

The food of limpets appears to be exclusively vegetable. A

freshly taken specimen always has the digestive tract stuffed

with a finely divided mass. of unrecognizable material mingled

with which are unicellular algze and bits of the cortical cells of

some of the larger ones. I have made no attempt to identify

these organisms. Intermixed with this material are great num-

bers of tiny stones which probably, like those found in a bird's

gizzard, aid in the comminution of the food. This is especially

necessary in the limpet since for the greater part of their extent

the walls of the alimentary tract are entirely devoid of muscles.

These bits of stone are very likely, at least in large measure,

fragments rasped off by the radula from the rocks together with

the small algze which cling to them. It has been suggested in

regard to Patella that the bits of alga cortex are in like fashion

detached, so to speak, by accident together with minute organ-

isms both animal and vegetable, which live upon the alga and

which constitute the real food of the limpet. Touching this

suggestion I can only say that I have never found in. any part

of the alimentary tract of Acmaa testudinalis remains which

could be interpreted as animal in nature and that I have found

the animal apparently feeding upon large alge which so far as

one could see, were absolutely free from smaller organisms.

As to habits of feeding I have never been able to observe the

act, but twice have, as I believe, interrupted it. In each case

the seaweed to which the animal was attached bore a mark, due

to the removal of the cortex, which served as a record of the

330 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

movements of the snout during feeding. The head is evidently

swept slowly from side to side while the animal dacks gradually

along the surface on which it is feeding, removing the food as it

goes from a band whose width is equal to the diameter of its own

mouth and whose length, disposed in a series of nearly parallel

but connected arcs, is proportionate to the length of the feeding

time. Removal of the tissue is effected by a licking motion of

the odontophore or “ tongue ” with its superimposed radula but

I have not been able to detect any independent motion of the

radula although I have made an especial search for a * chain-saw

movement" such as Huxley described in certain Heteropods,

and Geddes claims to have seen “in live limpets turned over on

their backs," and although there are in Acmea fragilis muscles

which seem adapted for the production of such a motion. I

have also been unable to gather any evidence as to the way in

which the individual teeth of the radula are used. Pilsbry has

suggested that in Rhipidoglossa the rounded form of the.

subradular cartilage probably determines a greater activity of

the median part of the radula and that this in turn accounts for

the greater specialization of the teeth in that region.

Respiration is in general aquatic and the mantle no less than

the gill serves as a respiratory organ, as is demonstrated by the

disposition of the blood vessels and the course of the flow.

Water passes in and out beneath the slightly raised shell and its

character may very possibly be tested as among some Pelecypods

by the minute tentacles which fringe the mantle. The shell is

usually thus raised so long as the limpet is undisturbed though

the slightest disturbance causes it to be tightly pressed against

the supporting rock.

Atmospheric air may, however, under certain circumstances

be respired. When the water in the aquarium has become

unduly warm or otherwise deprived of a part of its air, it is a

common sight to see the limpets about its edges with their bodies

half out of the water, the shell raised to the highest point, and

the head stretched forward so that the nuchal cavity may be as

widely as possible opened to the air. Such a position seems

explicable only on the theory that the animals are seeking to

supplement the imperfect gaseous exchange permitted by the

water by a true aérial respiration. . |

No. 461.] BIOLOGY OF ACMHA. 331

Limpets give evidence of the possession of only three special

senses: sight, touch, and the temperature sense. If they are

placed in water warmer than that to which they are accustomed,

they betray their uneasiness by restless wandering about. Vis-

ual sensations appear to be limited to the perception of light

and darkness. That light is objectionable only when associated

with heat seems indicated by the following experiment : a limpet

with the pebble to which it was affixed was removed from the

shaded to the sunny part of a tide pool. The water, being 12

to 15 inches deep, effectually protected it from the heat of the

sun and it showed no desire to move. When the pebble was

placed, however, in water only an inch or two deep and so con-

siderably warmer, the limpet exhibited lively discomfort and

crawled at once toward the shade. I have assumed that the

light-perceiving organs are the eyes but have taken no steps to

prove it.

The sense of touch is possessed by the entire body surface

though especially localized in the tentacles, both marginal and

cephalic, which are richly provided with tactile (Flemming's) cells.

The gill also, although without such cells, has an exquisite sen-

sitiveness and from its exploratory movements while the animal

is traveling, would seem to serve as an additional organ of

touch.

Though the sexes in Acmea testudinalis are distinct, the

shells show no sexual differentiation, whether in size or in form;

in the ripe animal, however, the sex can usually be determined

by a difference in the tint in that part of the foot which imme-

diately underlies the generative gland. The eggs when nearly

ripe assume a tint much like that known among dry-goods mer-

chants as “crushed strawberry," and the testis at the same

period is of a golden brown. On the left side of the body the

gland immediately overlies the foot and is perceptible through

its tissue as a patch of dull reddish or of creamy brown bounded

in the median plane by a sharp line corresponding to the plane

where it abuts against the green nephridium.

The breeding season appears to be a long one ; I have taken

ripe limpets near Boston as early as the thirteenth of April and

as late as the end of July. In Eastport they were still laying

332 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

during the first week in September. In each place the genera-

tive season probably ends a little before the water reaches its

maximum heat, which occurs at Eastport in September, at Bos-

ton in August. Thus all of a lot of specimens from Nahant in

the middle of August had the generative glands empty and the

same was true of a considerable part of those gathered at East-

port during the first few days of September. The eggs, which

are about + mm. in diameter are not dropped separately, as is

said to be the case in Patella, but are imbedded in a layer of

very thin mucus in which they lie one layer deep and at regular

distances apart. The mucus is secreted not by a special gland

but by the sole of the foot.

Fertilization is usually described as external. The only excep-

tion that I have been able to find to this statement is that of

Fischer, who in 1863, asserted that he had found the ovaries of

Patella filled with embryos already provided with the shell. Dr.

Dall kindly informs me that he was following this authority when

in 1879 he stated that the fertilization in Docoglossa is internal.

His statement in turn seems to have been the authority for that

made by Tryon in his Manual. While I am not prepared to

assert that fertilization is internal I wish to record the following

observation, which certainly points in that direction. About

nightfall a male was observed caressing a female. Both shells

were raised, that of the male overlapping the female and the

heads were placed side by side, the male stroking the female

with his tentacles. After a few passes he would turn as if he

were going to leave her and then come back. The proceeding

lasted for about half an hour, the female remaining quiescent

with tentacles folded about her head. At the end of this time

she moved forward, pressed the left side of the neck against the

corresponding region in the male so that the openings of the

two nuchal cavities were brought close together, and after

remaining a moment or two in this position turned and walked

away pushing with some difficulty between two other limpets

neither of which paid her any other attention than a momentary

touching with the tentacles. The nephridial papilla through

which the generative products are extruded lies not on the left

but on the right side of the nuchal cavity, but the ciliary current

No. 461.] BIOLOGY OF ACMA. 134

is outward on that side and inward on the left so that the posi-

tion which I have described would seem on the whole better

fitted than the reverse one for fertilization. On the other hand,

however, it should be said that when the animals were killed

twenty-four hours later, the ova of the female were unfertilized

and no spermatozoa were observed in her nuchal cavity or neph-

ridium. It should also be said that in two instances unfertilized

eggs have been laid in my aquaria, but as the same thing some-

times occurs with moths when pairing is prevented, no deduction

can be drawn from this fact.

The eggs, at least in the aquaria, are laid about nightfall and

the trochosphere is developed in the course of the next day.

I have made no attempt to watch the development. Growth

must be rapid, as one finds at Nahant in September and early

October large numbers obviously of the season's young, which

are four or five mm. in length. Sexual maturity is probably

acquired after the first winter, as I have taken ripe limpets in

April which were under a cm. in length.

The only enemy of the limpet of which I have had any

experience is the purple, Purpura lapillus. 1 have found occa-

sional shells bored by this mollusc and in one instance was able

to surprise it in the act.

HABITS OF WEST INDIAN WHITEBAIT.

AUSTIN H. CLARK.

Tur “tri-tri” or West Indian whitebait (Sicydium plumieri),

although of small size, is one of the important food fishes of

these islands. It is an inhabitant of the mountain streams,

and occurs in the quiet pools and eddies formed by the back-

water from rapids, from the lowlands well up into the highlands.

Its range is about the same on St. Vincent as that of the

“trout” (Agonostomus monticola), and, like that fish, it is

absent from certain of the rivers.

The tri-tri reminds one strongly of the common darter (o/eo-

soma nigrum olmsteadi) in habits. They are usually observed

lying motionless on the sandy bottom of pools, head up stream.

They will lie in one position for a long while, then, with a sud-

den jerk, move to another place. If disturbed they dart quickly

under the overhanging banks, or under rocks or logs in the

stream. When seen on sandy bottom, the color of these fishes

is a very light brownish gray, with seven or eight transverse

bands of darker. If over dead leaves, or on darker masses of

rock, they are a violet brown, the transverse bands being nearly

black. They harmonize so well with their surroundings that

they are distinguishable by a careful examination only. The

adults measure from 31 to 41 inches in length. In the waters

where this fish occurs there is a small slender crayfish, of the

same size and color, which is very easily mistaken for it. This

crustacean has the same habit of lying for a long while in one

position, then suddenly moving to another, and, if disturbed

takes refuge under the banks or under stones in the same way.

They may usually be distinguished by the fact that they move

tail first, and then occasionally crawl slowly on the bottom;

they also are much commoner near the sources of the rivers,

above the range of the tri-tri. :

In the dry season, the adult tri-tri migrate down stream to

335

336 THE AMERICAN NATURALIST. [Vor. XXXIX.

the sea, where they lay their eggs, probably near the mouths of

the rivers from which they descended,! and then apparently die,

as no adult fish are ever seen to return.

The young fry, when about $ to 1} inches in length ascend

the rivers by thousands during the wet season (August, Septem-

ber, and October), moving up stream in a continuous line near

or under the banks, as do the young of eels (Anguilla). When

in a stretch of comparatively quiet water they move steadily

onward; but in rapid water they progress by jerks, resting on

the bottom for a few seconds, then making a fresh dash onward

and taking a fresh grip on a pebble or rock with the ventral

sucker, and, after remaining quiet for a few seconds, dashing on

again. They even ascend vertical or overhanging surfaces,

over which a small amount of water is running in this way,

resting for a while, then moving upward an inch or so, resting

again, and moving on. Sometimes during one of these ascents

they are swept off and into the eddy below; but in a few min-

utes they are ready to try it again. I have seen as many as a

dozen moving up the face of a rounded rock a foot in diameter,

over which the flow of water was not enough to cover their

bodies. After a heavy rain the waters of the St. Vincent rivers

rise rapidly, and then fall again, leaving many little outlying

pools along the banks, which, under the influence of the

scorching tropical sun soon dry up, leaving dusty hollows.

Many of the fishes become cut off from the main stream at

such times, and, as the pools dry up may be seen jumping about

in the hollows, entirely covered with a thick coating of dust. If

these stranded individuals be placed again in the main stream,

they soon begin to ascend with the others as if nothing had hap-

pened. The tenacity of life of the young tri-tri is remarkable.

They will live for several hours in these dry situations, exposed

to the full rays of the sun.

The journey of the fry up the rivers occurs at the time when

! The fact that certain rivers in these islands, apparently suitable in every way

for these fish are not inhabited by them seems to point toward the fact that the

fish from the neighboring streams spawn in the vicinity of their mouths; other-

wise we should expect to find a few of the young straying into these uninhabited

streams every year.

No. 461.] WEST INDIAN WHITEBAIT. 337

the migratory shore birds from the north are making their brief

stay in these islands, and certain species appear to feed largely

on these fishes. On the Richmond River in St. Vincent, where,

on account of the lack of vegetation, consequent on the late

eruptions of the Soufriere, birds may be readily observed, I

found the following species feeding on the young tri-tri. Near

the mouth were blue herons (Florida cerulea cerulescens),

golden plover (Charadrius dominicus), turnstones (Arenaria

interpres), willet (Symphemia semipalmata), greater yellow-legs

(Totanus melanoleucus), lesser yellow-legs (7. flavipes), solitary

sandpipers (Helodromas solitarius), spotted sandpipers (Actitis

macularia), green herons (Butorides virescens maculata), and

kingfishers (Ceryle alcyon). The solitary sandpipers followed

the fish up into the lowlands at the base of the hills, the green

herons and kingfishers to the edge of, and even just within the

forests, while the spotted sandpipers are found well up into the

mountains. About the mouth of the river I also observed white

herons (Garzetta candidissima), great blue herons (Ardea hero-

dias), and fish hawks (Pandion haliaétus carolinensis), probably

attracted by the larger fish which were following the young tri-

tri in from the sea, and which were abundant about the river's

mouth.

On reaching the pools at the higher altitudes the fish select

some suitable spot and there remain until maturity, when they

return to the sea to deposit their eggs. I was unable to ascer-

tain just how long this period was. -

During their ascent of the streams, numbers of the young are

caught by the natives and eaten, either boiled (whole) or fried

into cakes. Although when cooked they bear strong resem-

blance to maggots, they are very good, tasting something like

whitebait. :

These fish, or a closely allied species, are abundant in certain

streams in Grenada, but are not found on the Grenadines.

Their local name is a corruption of that given them by the

original Caribs.

NOTES AND LITERATURE.

ZOÖLOGY.

Fishes and Ascidians. — The seventh volume of the now well

established Cambridge Natural History! contains accounts of the

fishes, ascidians, etc., and brings the series to within three of com-

pletion. This volume opens with a discussion of the Hemichordata

by S. F. Harmer. Dr. Harmer’s readable account of these very

interesting animals presents a concise description of the habits, dis-

tribution, and anatomy of such forms as Balanoglossus, Cephalodis-

cus, and Phoronis ; and concludes with a judicious summary of the

evidence as to their affinities. Dr. Herdman contributes the article

on the ascidians and amphioxus. This opens with a description of

the anatomy of a typical ascidian, after which a general systematic

consideration of the group is given. The chapter on amphioxus

deals in a brief way with the habits, structure, and embryology of

this important form. Here and there revised statements would have

improved the text, as for instance those on the condition of the eye

spots which were so admirably portrayed recently by Hesse. The

commendable feature of illustrating geographical distribution by a

chart is here marred by the fact that the signs used to represent

Branchiostoma and Asymmetron are not printed with sufficient clear-

ness to make them always unquestionable.

By far the larger part of the volume is given to the fishes, the

general account of which comes from Dr. T. W. Bridge and the

Systematic part on the teleosts from Dr. Boulenger. Dr. Bridge's

contribution is a safely conservative body of statement on the anat-

omy of fishes with a reasonable amount of natural history included

in the systematic consideration of all groups except the teleosts.

The account in the main is excellent but is marred here and there

by insufficiency. Thus in dealing with the ear the author treats the

organ as an unquestionable organ of hearing, omitting all mention of

its equilibration function, the only function thus far known for it in

such forms as the dogfish. Both Dr. Bridge's and Dr. Boulenger's

! The Cambridge Natural History. Vol. VII. Edited by S. F. Harmer and

A. E. Shipley. Macmillan Co., New York, 1904. 8vo, xviii + 760 pp., 440 figs.

339

340 THE AMERICAN NATURALIST. [Vor. XXXIX.

portions of the systematic account of the fishes are admirably illus-

trated and the accompanying charts of geographical distribution of

families, etc., add much to the lucidity of the presentation. This

volume is undoubtedly bound to rank high among its predecessors in

this excellent series.

G HE

Essays on Transformism. — Professor A. Giard! has collected

and published in book form seven of his essays which appeared dur-

ing the last twenty-five years and which all deal with evolutionary

matters. The essays, which are in no essential respects changed

from their original form, deal with the history of transformism, the

embryology of ascidians and the origin of vertebrates, biology and

taxonomy, the factors of evolution, Lamarck's principle and the

heredity of somatic variations, convergence in pelagic forms, and

animal symmetry ; and afford a convenient collection for those inter-

ested in the evolutionary speculations of this well known French

biologist.

GBP,

Morphology and Anthropology.? — The growth of anthropology

particularly in its relations to morphology is well exemplified in the

last number of the Cambridge Biological Series by Duckworth. ‘The

object of the volume is to set before the student a concise exposition

of man's place in Nature as determined by natural history methods.

The first part of the book deals with this question from the stand-

point of comparative anatomy and describes in an abbreviated way

the systems of organs in the mammals and especially in the primates,

devoting particular attention to the crania and teeth. Then follows

a condensed account of human embryology, after which anatomical

variations are taken up. These fill the greater part of the volume,

the last section of which deals with paleontological materials of

importance to anthropology. The condensation of so much sub-

stance into so small a space often seriously interferes with an ade-

quate treatment of the subject and one is often led to suspect that

the volame may be found more acceptable to the student who

is cramming for an examination than to the one who is seriously

engaged in a real study of anthropology; nor does the preface sug-

1 Giard, A. Controverses T; ransformistes. C. Naud, Paris. 8vo, viii + 180

PP-, 23 figs.

- Duckworth, W. L. H. Morphology and Anthropology. Cambridge Biologi-

cal Series, Macmillan & Co., 1904. 8vo, xxviii + 564 pp., 333 figs., 5 charts.

No. 461.] NOTES AND LITERATURE. 341

gest that this use of the book was far from the author's intentions.

However commendable such a standpoint may be, it is almost in-

variably assumed to the detriment of the really serious study of the

subject. As an examination compendium the volume has much to

recommend it; but as a contribution to the science of anthropology

it is much less satisfactory. The illustrations are numerous but often

crude and harsh.

G H. P.

Northern Plankton.!— The Hensen school of planktologists at

Kiel have undertaken, under the leadership of Professor Karl Brandt,

to issue a monograph of all the organisms found in the plankton of

northern seas above 5o? N. Associated with the editor-in-chief in

this undertaking are twenty specialists, each an authority on the

group of organisms with which he deals.

The literature which pertains to the complex of organisms com-

posing the plankton is widely scattered and much of it inaccessible

except in the large libraries at the great centers of learning. A com-

prehensive manual of the plankton will therefore be most welcome,

not only to the biologist at the seashore who wishes to acquaint him

self quickly with pelagic organisms, but also to the beginner who

for the first time beholds the marvels of the “tow.” The usefulness

of this work is enhanced by the fact that nearly every species is

represented by a “ Habitusbild ” or detail figure of diagnostic charac-

ters. Although limited in its scope to the fauna of northern and

arctic seas, and based largely upon the investigations along the

coasts of northern Europe, it is not a work of merely local interest,

useful only within the limits of latitude which the editors have

chosen, for the organisms of the plankton are in many cases cosmo-

. politan in their distribution and many species of the warm temperate

Atlantic are carried by the Gulf Stream far beyond 50° N.

The work is to consist of twenty-one sections numbered in zoólog-

ical and botanical sequence, each with independent pagination, and

issued in parts as rapidly as the papers are prepared. Part I con-

tains five of these sections, the pelagic tunicates by Drs. Borgert,

Apstein, and Lohmann; the Ostracoda by Professor G. W. Müller

1 Brandt, K. Mordisches Plankton. Lipsius & Tischer, Kiel and Leipzig, 1903.

Erste Lieferung. Sect. III, 21 pp. 24 figs.; VII, 15 pp-, 24 figs.;

34 figs. ; XIV, 32 pp., 33 figs.; XV, 52 PP-» 56 figs. 1901. M. 6.—

erung. Sect. XI, 7 pp-, 16 figs. ; XX, 29 pp» 25 figs.; XXL, 40 pp» !35 figs.

M. 3.60.

342 THE AMERICAN NATURALIST. [Vor. XXXIX.

and the Cladocera by Dr. Apstein; the echinoderm larve by Dr.

Th. Mortensen ; the Foraminifera by Professor Rhumbler ; and the

Tripylea (= Phxodaria Hkl.) by Dr. Borgert. Part II contains the

Ctenophora by Dr. Vanhóffen; the Schizophycez by Prof. N. Wille ;

and the Flagellatze, Chlorophycez. Coccosphzerales, and Silicoflagel-

late by Dr. E. Lemmermann.

As usual in works of composite authorship we find here consider-

able variety in the method and form of treatment, especially in mat-

ters of literature and synonymy. The admission of a large number

of fresh-water species in the sections dealing with the Schizophycez,

Chlorophycex, and Flagellatze seems illadvised. They occur in

brackish waters only and are generally adventitious even there, and

have no part in the marine plankton. The authors of the sections

dealing with the Ostracoda and Cladocera have excluded all adven-

titious forms from fresh water. Itisto be hoped that the appear-

ance of the remaining parts of this most useful manual may not be

long delayed.

CAK.

Wild Birds and their Music.'— Notwithstanding the present-day

abundance of popular guides to the study of our native birds, Mr.

Mathews has found an almost untouched field in preparing a guide

to the songs of the commoner species of the eastern United States.

In this artistic little volume of 262 pages, the songs and character-

istic notes of 82 species are carefully analyzed and set down in

musical notation or in line and dot diagrams, and these are so

explained as to be quite intelligible, even to one who has no techni-

cal knowledge of music. To the beginner in bird study, who finds

it much easier to hear birds than to see them, this book cannot fail to

be an aid in identifying the commoner song-birds. In addition to the

musical description, a brief diagnosis of each species is added,

together with a statement of its distribution. A number of plates in

wash or in color illustrate nearly all the birds described in the text.

All these are from drawings by the author, and although many of

them are admirable, others have evidently suffered much in the

reproduction. A good index enhances the value of this book for

field use.

GM A.

1 Mathews, F, Schuyler. Field Book of Wild Birds and their Music. New

York; G. P. Putnam’s Sons, 1904. 16mo, xxxv + 262 pp., illus. $2.00.

No. 461] NOTES AND LITERATURE. 343

BOTANY.

New England Ferns and their Allies.'— This attractive little

volume is intended as a popular guide to the New England ferns,

club-mosses, and horse-tails. In a preliminary chapter, the various

species are grouped first by their fruiting seasons, and then by the

nature of their habitats. Each species is then described briefly and

the more evident characteristics of closely allied forms are contrasted.

Brief remarks follow on the general distribution, habit, and manner

of fruiting. The descriptions are supplemented by one or more

excellent illustrations of each species from photographs of fresh

specimens. A key to the genera of the ferns treated, a glossary, and

an index conclude this handbook. It is substantially bound and of

a convenient size, and cannot fail to be of service to the increasing

class of out-of-door folk who wish to know the names of the plants

met with in their summer excursions.

G. M. A.

lEastman, Helen. New England Ferns and their Common Allies, an easy

Method of determining the Species. Boston and New York; Houghton, Mifflin

and Co., 1904. 12mo, xxi + 161 pp., illus.

(No. 460 was issued April 26, 1905.)

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CONTENTS

I, Fossil Grasses and Sedges : : =

IL Posterior Connections of the Lateral Vein of the Skate i ;

; DR, H. W. RAND ANDI. LURE

' IH The Skate as a ram for Classes in MEME ' 2

; Methods Ae

IV. Fossil Crabs of the Gay Head Kiew ee,

A Case of Abnormal Venous System in Necturus mermat

DpR.T

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AMERICAN NATURALIST.

Vor. XXXIX. June, 1905. No. 462.

FOSSIL GRASSES AND SEDGES.!

EDWARD W. BERRY.

IN number of species the Glumales (Graminales, Poales) is

one of the greatest angiospermous alliances. Aside from the

forms known as weeds or the cultivated species which have been

generally distributed by commerce and colonization, the group is

cosmopolitan, with common species in the northern and southern

as well as the eastern and western hemispheres. The distribu-

tion is very uniform, no one tribe or large genus being confined

toa single geographic area, abundant proof in itself that the

Glumales are an old type, whose generic evolution occurred far

back in geological history.

The known geological record does not, however, throw much

light on this subject. From the nature of the case the most we

can expect of fossil grasses and sedges is that they will give us

some idea when these types first appeared on the globe and when

they became abundant and widespread. We cannot expect to

unravel the botanical affinities of stray bits of leaf or indefinite

remains of inflorescence (Panicum), culms (Culmites), or rhi-

zomes (Rhizocaulon) in plants whose leaf-form and general struc-

! Published by permission of the Maryland Geological Survey.

345

346 THE AMERICAN NATURALIST. | [Vor. XXXIX.

ture is so uniform; nor can the names bestowed upon these

remains be taken to indicate relationship with the modern forms

except in a most generalized sense, indicating rather the personal

preference or convenience of their describers. However, as

organic remains of frequent occurrence and definite character

they deserve a place in fossil floras, and are perhaps more useful

to the geologist than to the botanist.

Summarizing the described species, we may note that we

have no evidence of grasses nor of sedges during the Paleozoic.

When parallel-veined leaves were supposed to indicate exclusively

Monocotyledonous character a number of supposed forms were

described from the Carboniferous. These have since been found

to be Calamarian or Sigillarian leaves. The remains from the

older Mesozoic show little improvement in definiteness. We

would expect grasses to have existed, and in fact a score of spe-

cies have been described from the Jurassic (Poacites, Bambu-

sium, etc.). Saporta in particular has described numerous species

of grass-like or sedge-like leaves under the name Poacites.!

The Cretaceous seems to have been very poorly provided

with sedges, if we may judge from the fossils, chiefly described

under the name Cyperacites ; the grasses, however, are quite

numerous during this period (Arundo, Phragmites, Culmites,

Poacites, etc.). With the ushering in of the Tertiary, both

grasses and sedges become more common, upward of two score

species of each type having been described from the Eocene.

It is in the Miocene, however, that the greatest display of fossil

grasses and sedges is made, there being numerous species

founded on culms, glumes, inflorescence, rhizomes, and leaves

(Carex, Cyperus, Cyperites, Cyperacites, Oryza, Panicum,

Arundo, Arundinites, Phragmites, Bambusa, Uniola, Palao-

Avena, etc.).

Referring more specifically to the Cyperaces, it may,be noted

that the middle and lower Cretaceous of this country, which

include the abundant, plant-bearing Potomac beds (Fontaine),

the Dakota group (Lesquereux), and the Raritan (Newberry,

1 As a matter of fact, Poacites as characterized by Brongniart in 1822 was

monotypic, and his species having been relegated to synonymy, the name is not

available for the Mesozoic species.

No. 462.] FOSSIL GRASSES AND SEDGES. 347

Hollick) do not show any recognizable remains of sedges.

Dawson has described one doubtful form from the lower Cre-

taceous (Urgonian) of British Columbia, and Heer has described

two species founded on rather more definite remains of leaves

from the Kome beds (Urgonian) of Greenland. This paucity

of remains renders the discovery of the following species of

some importance, as it was evidently abundant in the Atlantic

coastal plain at a time when those transition beds between the

typical Raritan and the typical Matawan were being laid down.

Carex clarkii sp. nov. (Fig. 1.)

Remains consist of fragments of leaves up to 6 cm. in length,

and varying in width from r.5 to 4 mm., averaging between 2

NT RUE ine bit from Grove Point, Maryland.

Fic. 1. — Specime

and 3 mm. in the specimens collected. Leaves slightly keeled,

evidently becoming somewhat thicker and narrower toward the

base. Midrib moderately prominent, lateral veins very fine and

scarcely discernible, except in the larger specimens.

348 THE AMERICAN NATURALIST. [Vor. XXXIX.

The type material was collected originally by Dr. Wm. Bullock

Clark at Grove Point, Maryland. Similar material has been col-

lected in a different leaf-bed on Grove Point by Bibbins and

Berry, who also collected it in less abundance at the Deep Cut

of the Chesapeake and Delaware Canal in Délaware. In over-

hauling my collections from Cliffwood, N. J., I found three small

fragments, hitherto undescribed, which are identical with the

specimens from further south. I now have twenty-two speci-

mens of this form from the Grove Point locality, five from Deep

Cut, and three from. Cliffwood. Five specimens were recently

collected by the writer from the west bank of Cheesequake

Creek one-half mile southwest from Morgan Station.

It has seemed best not to press the comparison with other

species from widely different geological horizons too closely.

Our species might readily enough be correlated with almost any

of the thirty-nine species of Cyperacex which Heer describes

from the Miocene of Switzerland, and the resemblance is also

very close to some of theleaves which Saporta refers to Poacites

(e.g. P. antiquior, tenellus, cercalinus). So much confusion

results from identifying as common, forms widely separated,

either geologically or geographically, when the determinations

are based upon any but the most complete material, that it has

seemed best to describe the American remains as a new species,

as I have no doubt it really is.

Passaic, N. J.

CONTRIBUTIONS FROM THE ZOÓLOGICAL LABORATORY OF

THE MUSEUM OF COMPARATIVE ZOÓLOGY AT HAR-

VARD COLLEGE. E. L. MARK, Director. No. 165.

POSTERIOR CONNECTIONS OF THE LATERAL

VEIN OF THE SKATE.

HERBERT W. RAND AND JOHN L. ULRICH.

FoR several years the senior author has used the skate to

illustrate to classes in the comparative anatomy of vertebrates

the main features of the primitive circulatory system of verte-

brates. The injection of the systemic veins of the skate is

attended with more or less difficulty, especially at the hands

of students of little experience, and even under the most favor-

able circumstances it is difficult, if not impossible, to secure a

complete injection of the veins by the methods ordinarily pre-

scribed (see, for example, T. J. Parker, '95, pp. 48-49). The

difficulty lies partly in the fact that the veins are well provided

with valves, which impede the flow of the injection mass in a

direction the reverse of that of the blood-flow, and partly in the

presence of large thin-walled sinuses which are likely to rupture

before the injection mass can be forced into the smaller vessels

and those 'more remote from the point of injection. Although

a large number of injected skates had come under observation

in the laboratory, the relations of certain of the veins in the

region of the kidneys had never been clearly demonstrated.

The veins of certain foreign species of skate have been well

described, notably by T. J. Parker ('81). Conditions similar to

those found in foreign skates are to be expected in our local

species. Nevertheless, it seemed to the authors to be worth

while to determine precisely the condition of the vessels whose

connections were in doubt, especially in view of the fact that

there was strong evidence of one striking difference between our

common skate and the species described by Parker, in the pos-

349

350 THE AMERICAN NATURALIST. (VoL. XXXIX.

terior connections of the lateral veins. The importance of a

complete knowledge of the details of skate anatomy is increased

by the fact that the skate is, in some respects, so peculiarly

adapted for use in the laboratory work of classes in comparative

anatomy. In another paper (Rand, :05) attention has been

called to the advantages of the skate for this purpose, where also

methods of injecting the blood vessels are discussed.

The first complete description of the connections of the lat-

eral vein of the skate is that given by T. J. Parker in his paper

“On the Venous System of the Skate (Raya nasuta)” in 1881.

Previous to Parker's description these veins had been imper-

fectly described by several anatomists. Monro (:85) observed

the lateral veins in skates, but did not determine their posterior

extent and connections. Robin (45) gave an incomplete and

not very clear account of the lateral veins of Raza clavata L.,

R. rubus L., and R. batis L., but at first regarded them as lym-

phatic vessels. He described the two lateral vessels as inoscu-

lating at their posterior ends. He afterwards recognized the

true nature of the vessels.

Parker ('81) gave a complete and clear account of the chief

veins of Raza nasuta. Figure 1 is a diagram showing the con-

nections of the important vessels as represented in the figure

accompanying Parker's paper. A similar figure is given in his

Zootomy ('95, p. 53). According to Parker's account, the lat-

eral vein (vz. 7), having received the several brachial veins,

opens anteriorly into the precaval sinus. Throughout its extent

along the lateral wall of the abdominal cavity, the lateral vessel

receives veins from the abdominal walls. The nomenclature

used above is not that of the paper cited, but corresponds to

that of Parker's later paper (’86) on the blood vessels of Muste-

lus antarcticus. Posteriorly it receives the femoral vein and just

back of that point becomes continuous with a large trunk which

* passes dorsalwards, .... curving along the posterior wall of the

pelvic cavity, then passing on to the lateral wall of the cloaca,

along which it takes its course as far as to the rectal gland,

where, with its fellow of the opposite side, it enters a hinder

prolongation of the cardinal sinus, first receiving numerous small

veins from the cloaca and rectum” (Parker, '81, pp. 415-416).

No. 462.] LATERAL VEIN OF SKATE. 351

** These latter, I have no doubt," says Parker, “although I have

not actually proved it, anastomose with factors of the portal

vein" (p. 416). The large trunk which constitutes a direct

continuation of the lateral vein from its femoral region into the

cardinal sinus was called by Parker the 2/o-hemorrhoidal vein

because it “seems to correspond in all essential respects to the

iliac vein " and “also receives the hemorrhoidal veins from the

rectum and cloaca” (p. 416). The arrangement described by

Parker is virtually that of a continuous large venous trunk open-

Fic. 1.—Venous system of Raia nasuta. After T. J. Parker. sn. cf., cardinal sinus;

sn. p., hepatic sinus; sz. frecav., precaval sinus; sw. vm., Veno

us sinus; vx. ór., brach-

ial v vn. fe., femoral vein; vn. kær., hzmorrhoidal veins; v». il-her., ilio-haem-

eins; :

orrhoidal veins; va. jug. if., inferior jugular vein; vw. Z., lateral vein ; v. f'cr., post

cardinal vein ; vz. frecr., precardinal vein.

ing at its anterior end into the precaval sinus and at its posterior

‚end into a posterior extension of the cardinal sinus, its chief

tributaries being the brachial and femoral veins and veins from

the abdominal wall.

Jourdain ('59) in his

oes not mention the lateral veins, but

«Recherches sur la Veine Porte Rénale,"

describes the femoral

”

352 THE AMERICAN NATURALIST. (VoL. XXXIX.

veins in Raia c/avata L. as opening each into the corresponding

renal portal vein.

Hochstetter ('88) gives the following account of the lateral

veins of Spinax [= Squalus] acanthias: “Neben den Venæ sub-

clavie münden caudalwärts von ihnen jederseits eine Vene, in

die Cardinalvenen, die Seitenvene..... Diese beiden Gefässe

wurzeln in einem Venennetze, welches die Kloake umspinnt und

mit den Pfortaderzweigen des Enddarmes anastomosirt. Aus

diesem Netze gehen rechts und links die beiden Venen hervor,

welche angeschlossen an die dorsale Fläche des Beckenknorpels

zunächst die Vene der hinteren Extremität aufnehmen und

hierauf umbiegend, geradeaus kopfwárts verlaufen und auf diesem

Wege die Venen der Bauchmuskeln aufnehmen " (p. 126). In

the rays, Hochstetter says, the lateral veins exhibit substantially

the same condition as that described for Squalus.

We were led to investigate the posterior connections of the

lateral vein of the skate owing to the fact that, in the numerous

animals which had come under observation in the laboratory,

there had never been seen the least evidence of the “ ilio-

hemorrhoidal” trunks described by Parker for Raza nasuta. In

a freshly-killed skate (R. erinacea or R. levis, Fig. 4) the lateral

veins, lying just beneath the peritoneum, are conspicuous ves-

sels because of the blood contained in them. They may be

followed back to the pelvic region, where they disappear from

view. The cardinal sinus is usually well filled with blood and a

posterior extension of this sinus may be traced back to the base

of the rectal gland. This extension evidently corresponds to

the “hinder prolongation of the cardinal sinus” described by

Parker as receiving the ilio-hæmorrhoidal veins, but no large

trunks are to be seen opening into it. Attempts to trace the

uninjected vessels by dissection resulted negatively, so far as any

connection between the hind end of the lateral vein and the car-

dinal sinus is concerned, although a connection of the lateral

vein with a vein from the pelvic fin was found. Furthermore,

observation of a large number of injected skates had given no

evidence of the existence of “ilio-hæmorrhoidal ” veins. These

injections, however, being of raw starch or of plaster of Paris,

were not calculated to show a connection between lateral vein

No. 462] LATERAL VEIN OF SKATE. 353

and cardinal sinus by means of minute vessels, if such existed.

Accordingly we undertook to determine if any connection what-

ever was to be demonstrated.

Six fresh skates were secured, four of them being the common

Raia erinacea and two AR. /evis. Our operations and results

upon these six animals are described below. In each case the

caudal vein was injected for the purpose of differentiating the

renal portal connections. The celloidin injections were made

with very thin, easily flowing celloidin colored with finely pulver-

ized carmine or Prussian blue. Careful dissections and draw-

ings of the injected vessels were made by Mr. Ulrich.

I. Raia levis: young male.

1. Renal portal system injected, va the caudal vein, with blue

celloidin.

Minute separated masses of the celloidin appeared in the post-

cardinal veins, apparently having passed through the renal capil-

laries. A considerable quantity of celloidin from this source

collected in the cardinal sinus and some of it made its way back

into the posterior or rectal prolongation of that sinus.

2. Left lateral vein injected posteriorly with red celloidin.

The red mass appeared on the walls of the cloaca and rectum

in a close network of very fine vessels extending forward to, and

a little beyond, the base of the rectal gland. Small vessels con-

nected with this network conveyed the celloidin along the

ventral margin of the mesorectum, in the region of its attach-

ment to the rectum, apparently into the posterior end of the

rectal prolongation of the cardinal sinus. Here an interval of

only three or four millimeters separated the blue and red injec-

tion masses.

The dissection of this fish proved that both the red and the

blue celloidin had entered the rectal prolongation of the cardinal

sinus. The failure of the two masses actually to meet was

doubtless caused by the inclusion between them of a quantity of

gas for which there was no avenue of escape. The lateral vein

received two trunks from the pelvic fin. The larger one of the

two emerged from the fin dorsal to the end of the girdle and

354 THE AMERICAN NATURALIST. | (Vor. XXXIX.

just posterior to the iliac process. The smaller vein left the fin

on the anterior side of the first or pre-axial fin-ray.

II. Raia erinacea: young male.

1. Renal portal system injected, via the caudal vein, with blue

celloidin.

A small amount of the celloidin appeared in the cardinal

sinus.

2. Left lateral vein injected posteriorly with red celloidin.

The mass did not appear on the rectum.

During the progress of the injection the posterior margin of

the left pelvic fin was cut away. The red celloidin escaped

from a small vessel lying along the median edge of the clasper.

In the dissection of this fish the lateral vein was traced to the

wall of the cloaca, where it was lost in fine branches. A large

vein from the pelvic fin was found opening into the lateral vein

ata point dorsal to the girdle and just posterior to its iliac

process.

III. Raia erinacea : female.

1. Renal portal system injected, via the caudal vein, with

blue (raw) starch. ;

The starch mass did not pass into the cardinal sinus.

2. Left lateral vein injected posteriorly with red celloidin.

A fine anastomosing network on the cloaca and rectum was

injected, as in I.

The left pelvic fin was cut, asin II. There was slight evi-

dence of the red celloidin at the cut surface.

By dissection, the lateral vein was traced back along the pelvic

region of the abdominal wall and onto the lateral wall of the

cloaca along which it ran, giving off numerous branches and

rapidly diminishing in caliber, to a point about 15 millimeters

posterior to the rectal gland, where it became completely lost in

a fine network.

The lateral vein was found to receive from the pelvic fin a

fairly large trunk which emerged from the fin on the anterior

side of the first or pre-axial fin-ray.

No. 462.) LATERAL VEIN OF SKATE. 355

IV. Rata erinacea: large male.

I. Blue starch injected into the caudal vein.

The blue starch appeared in the left lateral vein and filled the

greater portion of it, together with some of its branches from

the body wall.

Dissection of the animal showed that the renal portal system

was fully injected. The position and connections of the vein

which put into direct communication the renal portal and lateral

systems are represented in Figure 2. Lying transversely on the

left dorsal body wall was found a large vein (Fig. 2,x) opening at

ie „par:

Nut 1 oe aM

RS,

(od

“| \

UN. ren.aff. C |

N Ph /

ki Pa

Ten. I

rng A

\ ^ JF

AD 8

ih as asa aa UN ren-pr 1.

-————— UN. Ca.

Fic. 2.— Showing the connection found in Case IV between the renal — system ae ui

lateral vein. far. — — es of ei p qm and lateral veins; ren y;

un. ca., caudal vein; va. Z, lat erent. ens veins; v. ren-frt.,

ein ;

renal portal vein; r, vein demi renal poral a hof Tateral veins.

356 THE AMERICAN NATURALIST. | (Vor. XXXIX.

its one end into the left lateral vein, and at its other into a large

anterior renal portal component, which was virtually a direct

continuation of the renal portal vein itself forward on the dorsal

body wall. Jourdain ('59) describes a similar anterior component

of the renal portal system.

The extreme posterior end of the lateral vein was found to be

not injected.

V. Raia levis: very large female.

1. Renal portal system injected, via the caudal vein, with

blue starch.

2. Left lateral vein injected posteriorly with red celloidin.

A particularly full injection of the branches of the posterior

part of the lateral vein was secured. The mass appeared on

the walls of the cloaca and rectum in an anastomosing network

of fine vessels, which were traceable along the rectum to a region

about one centimeter anterior to the duct of the rectal gland.

The mass was seen also in small vessels on the ventral margin of

the mesorectum, and a considerable quantity of it passed through

the rectal extension of the cardinal sinus into the main part of

that sinus.

The left pelvic fin was cut, as in preceding cases, and the red

mass escaped from small vessels along its median edge.

The dissection of this animal demonstrated clearly a connec-

tion between the venous network on the rectum and the cardinal

sinus. The lateral vein was traced forward a short distance on

the side of the rectum and there broke up into fine branches

which anastomosed with vessels of the network. Along the

margin of the mesorectum, in the region of the base of the

rectal gland, several small vessels resolved themselves out of the

network and communicated with the posterior end of the rectal

extension of the cardinal sinus.

From the pelvic fin the lateral vein received two large

trunks and one very small vein (see Fig. 4). The largest trunk

emerged from the fin just posterior to the iliac process of the

girdle, corresponding, therefore, with the one vein found in II

and with the posterior one of the two veins found in I. This

No. 462.] LATERAL VEIN OF SKATE. 357

trunk, from its position and size, is doubtless entitled to the

name, femoral vein. It receives one large branch from the

median side of the basipterygium. The remainder of its

branches are distributed upon the external side of the basi-

pterygium, collecting the blood from much the greater portion

of the fin. A second and considerably smaller vein emerged

from the fin on the anterior side of the pre-axial fin-ray, corre-

sponding with the vein found in III and with the anterior one

of the two veins found in I. The branches of this vein were

distributed around the large pre-axial fin-ray, the main axis of '

the vein lying along the anterior side of the ray.

The third one of the three veins mentioned as entering the

lateral vein from the pelvic fin was a very small vessel which

lay just anterior to the iliac process of the girdle.

VI. Raia erinacea: small female.

1. Renal portal system injected, via the caudal vein, with

blue celloidin.

A trace of the celloidin appeared in the right postcardinal

vein.

2. Right lateral vein injected posteriorly with red celloidin.

The mass entered a fine network of vessels on the cloaca and

rectum, passed through minute vessels lying along the ventral

margin of the mesorectum, and a small quantity of it collected

in the rectal extension of the cardinal sinus.

By dissection, the lateral vein was traced up to the wall of the

cloaca (see Fig. 3), where, at a point nearly in the same trans-

verse plane with the anterior end of the external cloacal aper-

ture, it divided into two branches. Each of these immediately

broke up into fine branches which anastomosed with vessels of

the network. On the dorsal wall of the rectum and just behind

the rectal gland, the network resolved itself into a system of

fine vessels (Fig. 3, A and B, vz.) lying nearly parallel with one

another, frequently anastomosing, and converging forward into

fewer and larger vessels in such a way that there was a gradual

transition from the rectal network into the single very narrow

lumen of the posterior tip of the cardinal sinus.

No veins from the pelvic fin were injected.

358 THE AMERICAN NATURALIST. [Vor. XXXIX.

Examination of a number of skates which had been injected

(by students) with starch or a starch-gelatin mixture (see Rand,

:05) brought to light several animals in which the rectal

venous network had been more or less completely filled from

the cardinal sinus. In these cases, the lateral vein had been

injected forward, but not backward. The cardinal sinus had

do. JE

Fic. 3.—Showing the relation found in Case VI between the posterior end of the lateral vein

Ath A 1 1

Th 1 1 f +h

but the rectum is twisted through 90°

* D r ’

so as to bring into view the right side of its anterior region as well as the right side of

the rectal gland and mesorectum.

C ti ( 1 CERT -

. g the rectum at a-a.

ap. clc., cloacal aperture ; cZc., cloaca; g/.rt., rectal gland ; »s'7?., mesorectum; ref. vn., ven-

ous network on cloaca and rectum; rZ., rectum; sz. cr., rectal prolongation of cardinal

sinus ; Un., veins connecting rectal venous network with cardinal sinus; vz. /., lateral

vein.

filled from the precaval (Cuvierian) sinus and the mass had

made its way back through the rectal extension of the cardinal

sinus into the rectal network. This network, therefore, may be

injected either from behind, by way of the lateral vein, or from

before, by way of the cardinal sinus. Figure 4 shows the lat-

eral vein in its entire extent, with its connections as found in

our injected skates.

„. Un. Prec.

Ventral view.

Fic. 4.— The lateral v dit Raia erinacea and R. levis.

arc. pct., pectoral girdle ; af. clc., cloacal aperture : ba’ft., basipterygium ; céc., cloaca;

rt., rectal gland; fre. il., iliac process of pelvic girdle; r. pinn., pre-axial ray of

pelvic fin; rez. va., 1 Joaca and rectum; r?., rectum; sz. cr., cardinal

sinus; sz. AØ., hepatic sinus; sz. precav-, precaval sinus ; vn., venous sinus; v7.

ial veins; væ. jug. if., inferior jugular vein; vr. l., lateral vein; vs. f’cr.,

y., veins from pelvic fin; vn. precr., precardinal vein.

ór., b

postcardinal vein; vz. 24

360 THE AMERICAN NATURALIST: [VoıL. XXXIX.

Do the veins of the rectal network communicate directly with

the posterior factors of the hepatic portal system, as stated by

Hochstetter for Squalus, and as thought probable by Parker ('81)

for Raza nasuta ?

Good starch injections of the intestinal veins often result in

the demonstration of a venous network on the rectum in the

region of the base of the rectal gland. The network which has

been demonstrated by injection from the lateral vein often ex-

tends into the same region. It is improbable that there should

be two distinct and non-communicating sets of veins in this same

region of the intestine. In one case (I) the red celloidin passed

through the venous network on the rectum and appeared in a

very small vessel which was identified, with a fair degree of cer-

tainty, as the extreme posterior end of the mesenteric or dorsal

intestinal vein, the hindmost trunk of the hepatic portal system.

The failure of the celloidin to flow freely through the network

into the hepatic portal vessels, granting that the connection

exists, might well be due to the solidifying of the celloidin in the -

fine vessels of the network as the result of contact with moisture.

The senior author has seen injected skates in which a yellow

starch mass, injected backward into the mesenteric vein, appeared

actually to meet, in the region of the rectal gland, a blue starch

mass which had made its way into the rectal network via the

rectal extension of the cardinal sinus, the two masses clearly

lying in the same vessels.

With a view to getting more conclusive evidence as to the

relation between the rectal network and the hepatic portal sys-

tem, the senior author secured some fresh skates of the common

species, A. erinacea (at Woods Hole, Massachusetts, through

courtesy of officials of the United States Bureau of Fisheries

and of the Marine Biological Laboratory) and made injections

in the following way. A fluid consisting for the most part of

water, but containing a small amount of glycerin and colored

with finely pulverized insoluble Prussian blue, was injected back-

ward into one of the lateral veins. The rectal network imme-

diately became very fully injected and the blue fluid passed

along the mesorectum into the cardinal sinus, in the manner

already described. Then a ligature, which had previously been

No. 462.] LATERAL VEIN OF SKATE. 361

passed around the narrow posterior end of the rectal extension

of the cardinal sinus, was tightened so that further flow of the

fluid into the cardinal sinus was prevented. A very light pres-

sure on the syringe was maintained, with the result that the

blue fluid appeared in the posterior region of the mesenteric vein

and in its posterior branches, whence it passed forward, filling

most of the veins on the intestine. The intestinal arteries were

then injected, via the anterior mesenteric artery, with a fluid

similar to that used for the veins, but colored with pulverized

carmine. There was no interference or mingling of the blue

and red fluids on the intestine, nor was there any evidence that

the blue fluid had passed through capillaries into arteries.

The injection of the Prussian blue fluid backward into the

mesenteric vein gave similar proof of the continuity of the portal

veins and the rectal network. The fluid appeared in extremely

fine vessels over the entire intestinal wall and, passing through

the rectal network, entered the cardinal sinus and both lateral

veins. 5

To summarize, in Raza erinacea and R. /evis (see the dia-

gram, Fig. 5):—

(1) There are no veins similar to the large ilio-haemorrhoidal

veins described by Parker for R. nasuta.

(2) The two lateral veins have a common origin in a close

network of fine vessels distributed over the walls of the rectum

and cloaca.

(3) This venous network communicates with the cardinal

sinus by means of small vessels lying along the ventral margin

of the mesorectum, in the region of its attachment to the rectal

gland.

(4) The vessels of the rectal network communicate with the

posterior factors of the hepatic portal system as stated by

Hochstetter and as thought probable by Parker. :

(5) The lateral vein receives the blood from the pelvic fin,

there being, in addition to the chief femoral vein, one or two

smaller vessels from the fin which open into the lateral vein

independently.

The relations of the lateral veins to other parts of the venous

System are, therefore, substantially as described by Hochstetter

362 THE AMERICAN NATURALIST. [Vor. XXXIX.

for selachians in general, except for the connection with the

cardinal sinus va the cloaco-rectal network.

It is probable that the flow of blood throughout the entire

length of the lateral vein is from the cloaco-rectal network and

toward the precaval sinus. The steady increase in the diameter

of the vein as it leaves the network and curves along the pelvic

region points toward this view, as does also the presence, in the

pelvic region of the vein, of valves placed so as to impede a

posterior flow. The cloaco-rectal network is doubtless an indif-

ferent region as regards flow, the blood passing from it into

either the hepatic portal system, the cardinal system, or the

VOTI DVLZZ

(P p

Fa. 7

CU» UATROR RU

BA NON

UN. MSI’EenE

[ gir we» D

ir) pnl

SS SSS

up OD 149

OX) Os)

Fic

3. 5.— Diag ic side view of cloac tal region, showing relations of lateral veins,

cardinal sinus, and mesenteric vein. af. cle., cloacal aperture ; arc. plv., pelvic girdle;

gl. ri., rectal gland; z#., intestine; ms’r/., mesorectum ; ret. Vn., tworl

cloaca and rectum; rż., rectum; s»

- cr., cardinal sinus; sx. cr’., rectal prolongation of

cardinal sinus; vx. 7. dx , right lateral vein; v». 7. s., left lateral vein; v». ms’en

mesenteric vein.

lateral veins. The blood from both the pectoral and the pelvic

fin of one side, therefore, passes to the heart by the same vein.

In two of the dissections made by Mr. Ulrich a suggestive

condition was found. The lateral vein, steadily diminishing in

caliber, was traced to the wall of the rectum where, at first

glance, one would say that it became lost in the network. But

close inspection revealed an extremely fine vessel which was

virtually the continuation of the lateral vein along the side of

the rectum. This fine vessel maintained a fairly straight course

through the midst of the rectal network, of which, by reason of

No. 462.] LATERAL VEIN OF SKATE. 363

frequent anastomoses, it was really a part, and could be traced

forward to the cardinal sinus, except for one or two interruptions

where it completely lost itself by branching into the network.

If the relatively short gaps in the continuity of this fine vessel

were filled in and if the continuous vein thus formed should

become nearly as large as the largest part of the lateral vein,

the result would be the ilio-haemorrhoidal vein described by

Parker. The condition just described suggests the presence of

either an incipient or a rudimentary “ilio-haemorrhoidal " con-

nection between lateral vein and cardinal sinus. An examina-

tion of embryonic stages might yield further information.

The direct connection existing in one case (IV, p. 355) between

the renal portal system and the lateral vein is due apparently to

the anastomosis of a parietal factor of the renal portal system

and one of the parietal branches of the lateral vein. Normally

these two sets of veins on the dorsal wall of the abdominal

cavity come into close relation at their initial ends. This

unusual relation of the lateral vein to the renal portal system is

of no great importance in itself, but it is suggestive in connec-

tion with the theory that the lateral veins of elasmobranchs

are represented in higher vertebrates by the abdominal vein.

Just as the two lateral veins in the elasmobranch collect the

blood from the walls of the cloaca and from the pelvic fins, so,

in the urodele amphibian, the abdominal vein receives the veins

from the urinary bladder (which is a derivative of the cloaca),

and the two posterior components of the abdominal vein receive

the veins from the hind legs. The chief difference is that, in

the elasmobranch, the lateral system has no direct connection

with the renal portal system, while in the amphibian each ot the

two posterior components of the abdominal vein is directly

connected with the corresponding afferent renal portal vein.

Development, as is well known, affords some evidence in favor

of the homology. In consequence of the slight abnormality

described above, there occurs in the veins on one side of the

body in the kidney region of a skate an arrangement similar in

all essential respects to that in amphibians. Such an anasto-

mosis of a lateral and a renal portal component occurring on

both sides of an elasmobranch and in the posterior region of the

364 THE AMERICAN NATURALIST. (VoL. XXXIX.

kidneys would yield a condition precisely like that seen in the

relations of the abdominal, iliac, and renal portal veins of a

urodele. This abnormal skate serves at least to suggest a pos-

sible way in which one of the differences in the arrangement of

the veins of elasmobranch and amphibian may have arisen.

BIBLIOGRAPHY.

HOCHSTETTER, F.

'88 eitráge zur vergleichenden Anatomie und Entwicklungsgeschichte

des Venensystems der Amphibien und Fische. Morph. Jahrb., Bd.

13, Taf. 2-4, 7 Textfig.

JOURDAIN, S.

'59. Recherches sur la veine porte rénale. Ann. Sci. Nat., 4me

Série, Zoöl., Tom. 12, pp. 134-188, 321—369, 5 pls.

Monro, A.

185. The Structure and Physiology of Fishes. Edinburgh, 1785, 128

'81. On the Venous System of the Skate (Raja nasuta). Trans. and

Proc. New Zealand Inst., vol. 13, pp. 413-418, 1 pl.

PARKER, T. J.

'86. On the Blood-Vessels of Mustelus antarcticus. Phil. Trans. Roy.

Soc. London, vol. 177, part 2, pp. 685-732, pls. 34-37.

PARKER, J. J

95. A Course at Instruction in Zootomy (Vertebrata). ^ Macmillan,

London and New York, xxiii + 397 pp., 72 figs.

RAND, H. W.

:05. The Skate as a Subject for Classes in Comparative Anatomy ;

Injection Methods. Amer. Naturalist, vol. 39, pp. 365-379, fig. 1.

Rosin, C.

'45. Vaisseaux lymphatiques chez les poissons. Revue Zool. par la

Société Cuvierienne, Paris, Tom. 8, pp. 224-233, 461.

CONTRIBUTIONS FROM THE ZOÖLOGICAL LABORATORY OF

THE MUSEUM OF COMPARATIVE ZOÖLOGY AT HAR-

VARD COLLEGE. E. L. MARK, Director. No. 166.

THE SKATE AS A SUBJECT FOR CLASSES IN

COMPARATIVE ANATOMY; INJECTION

METHODS.

HERBERT W. RAND.

THE selection and obtaining of material for the laboratory

work of classes in zoölogy, and the best methods of treating

that material, are matters of considerable importance to those

having such work in charge. My use of the skate for several

years past has impressed me with the belief that it is, in some

respects, peculiarly adapted for use in the laboratory work of

classes in the comparative anatomy of vertebrates. If I am not

mistaken, the advantages of the skate for this purpose and the

practicability of using it are not always fully realized, especially

by teachers who are situated at some distance from the sea. In

view of this fact, I think it worth while to call attention to cer-

tain points wherein the skate seems to me to be a superior sub-

ject for laboratory work. In addition, I shall consider methods

of injecting the circulatory system of this fish.

If a student in comparative anatomy is to study a fish as

a representative of the class, obviously it should be one which

exhibits as nearly as possible primitive vertebrate conditions, —

therefore an elasmobranch. If an amphibian is to follow the

fish, it should, of course, be one of the tailed amphibians rather

than the highly specialized frog. The elasmobranch, in its gen-

eral anatomy, is much more directly and closely comparable with

the urodele than is any teleost. To start a student in verte-

brate anatomy on the dissection of a teleost and to follow that

with the frog, as a representative of Amphibia, is as poor a pro-

gram as could be arranged, if it is the intention that he should

365

366 THE AMERICAN NATURALIST: | (Vor. XXXIX.

see for himself something of the main course in the evolution

of the structure of higher vertebrates. The study of types situ-

ated near the main line of vertebrate descent is to be preferred

to the study of extremes of specialization. It seems to me to

be questionable wisdom to let enthusiasm for local fauna lead

to the selection of a teleost, for class study, provided that marine

material is obtainable, and provided further that only one repre-

sentative of Pisces can be studied.

Among the elasmobranchs, the sharks depart less conspicu-

ously from primitive conditions than the rays and therefore,

theoretically, the dogfishes are to be preferred to the skates for

general laboratory purposes. The dorso-ventral flattening of

the skate, however, gives it a certain superiority as a subject

for dissection. As a result of the flattening, most of the organs

of the animal are much more easily accessible than they are in

the dogfish. This advantage is of particular importance when

it comes to the injection and dissection of the blood-vessels.

The abdominal cavity of the skate is completely exposed with

a minimum of cutting. This cavity is a broad and very shallow

one so that, its ventral wall having been removed, a slight dis-

placing of viscera brings all its organs immediately into view

and renders its chief blood-vessels very easy of access.

It is a consideration of no small moment that the skate, dur-

ing injecting and dissecting operations, lies in the position most

favorable for work — that is, flat on its back — without any

special device for holding it there, while it is not always easy

to support a dogfish in a desired position.

In the dissecting and study of the circulatory organs, the

flattening of the skate is especially advantageous, because, one

might say, it tends toward the projecting of the blood-vessels

into one plane, resulting in an almost diagrammatic arrangement

of them.

A practical point which will often lead to the selection of the

skate, if elasmobranch material is to be used, is the fact that

skates can be obtained during a large part of the year when

dogfish can not. Mr. F. T. Lane, of Rockport, Massachusetts,

in response to my inquiry, writes me that he can catch skates

off Cape Ann at any time of the year, except during storms,

No. 462.] THE SKATE FOR ANATOMICAL STUDY. 367

whereas dogfish can be taken in abundance only during June,

July, and August, and sometimes in September. No dogfish

are to be caught, he says, from the first of December to the

first of May. Also in reply to inquiries of mine, Dr. F. B.

Sumner, director of the laboratory of the Woods Hole station of

the United States Bureau of Fisheries, states (largely, he says,

on the authority of Mr. Vinal Edwards, collector for the station)

that skates can be taken in the vicinity of Woods Hole at any

time of year except in January, February, and March. Smooth

dogfish (Mustelus canis) “can be taken in considerable numbers

from the latter part of June till November first, being most

abundant soon after their appearance late in June,” while spiny

dogfish (Squalus acanthias) are abundant only in May and early

June. Neither species of dogfish can be taken in that region

from the middle of November until the first of May. Similar

statements as to the occurrence of dogfish and skates are made

by Dr. Hugh M. Smith (98) in his list of “The Fishes Found

in the Vicinity of Woods Hole."

It appears from the foregoing statements that, so far as the

New England coast is concerned, fresh skates, suitable for injec-

tion purposes, may be had throughout the greater part of the

year, or possibly throughout the whole year, while fresh dogfish

can be obtained during not more than five, or possibly six,

months of the year. Furthermore, the dogfish are most abun-

dant and most easily taken during the summer months when

they are least wanted for laboratory purposes in schools and

colleges, except as they may be preserved then and stored for

future use. To be sure, dogfish may be collected and injected

in the summer and preserved for use later in the year. But, to

my mind, there are serious objections to giving a student his

animals already injected. He should make his own injections.

The injecting of the animal which he'is to dissect gives the

student information which he will not get so well in any other

way, besides being a valuable means of developing skill in

operating.

As regards the practicability of shipping fresh elasmobranch

material to points distant from the coast, there is no sufficient

reason why, in these days of rapid transportation, such material

368 THE AMERICAN NATURALIST. | (Vor. XXXIX.

cannot be had by almost any institution in the country, however

remote from the coast. Fish properly packed, so as to secure

coolness and freedom from too great pressure, will endure well

several days' transportation, especially in the cooler seasons of

the year. Skates which are intended for injecting for non-his-

tological purposes are not injured by freezing, provided that they

are not exposed to alternate freezing and thawing.

A point of minor importance is the fact that it is easier to

secure good preservation of skates than of dogfish. The flat-

tening of the skate's body facilitates the penetration of the pre-

serving fluid to the deep organs. Furthermore, to get sexually

mature animals, it is necessary to use dogfish of such large size

that the preservation and storing of material for a large class

become a serious problem. The same number of small sexually

mature skates makes a much less bulky mass of material.

The objection that the skate is a highly specialized elasmo-

branch does not apply, to any great extent, to its internal anat-

omy. The specialization involves chiefly the general form of

the body. The skeleton and muscles are the systems most

affected. The remaining organs undergo relatively unimpor-

tant changes in position incident to the flattening of the body.

In their essential morphological characters and relations they

are closely comparable to those of the shark-like elasmobranchs.

From a practical point of view, it might be said that the special-

ization of the skate is in the direction of ee for labora-

tory purposes.

The plan which has been followed for several years pastin the

laboratory of vertebrate comparative anatomy at Harvard Uni-

versity seems to me to be an excellent one. The student first

makes a general dissection of the dogfish, exclusive of the

blood vessels, then injects a fresh skate for the study of the

circulatory system. By this arrangement he becomes familiar

with the anatomy of the more primitive elasmobranch and

studies a typical elasmobranch circulatory system under condi-

tions far more favorable than those offered by the dogfish. At

the same time, his familiarity with the dogfish enables him to

detect the essential elasmobranch characteristics i in the skate and

to comprehend the nature of its specialization. Thus, he is

No. 462] THE SKATE FOR ANATOMICAL STUDY. 369

given an opportunity for observing, in an appreciative way, a

remarkable case of modification of form. If the student’s main

work is on the skate, he should at least be given an opportunity

to compare skate and dogfish far enough to make clear to him

the character of the skate's departure from the more primitive

conditions.

INJECTION METHODS.

Injection of the Veins of the Skate— What I have to say

about the injection of the veins of the skate is with special refer-

ence to the best method by which this operation may be per-

formed by students who have had little or no experience in such

work. It is assumed that the injecting is to be done by means

of an ordinary hand syringe.

A complete injection of the systemic veins of the skate is

difficult to obtain, even under the most favorable circumstances,

partly because the veins are well provided with valves which

impede the flow of the injection mass in a direction the reverse

of that of the blood-flow, and partly because of the presence

of large thin-walled sinuses, which are likely to rupture before

the injection. mass can be forced into the smaller vessels and

those more remote from the point of injection.

The vessels most accessible for the injection of the systemic

veins are the postcardinal veins in their renal region, the venous

sinus, and the lateral veins. Parker ('95) recommends intro-

ducing the injection mass at the venous sinus, the flow of the

mass being directed backwards, or away from the heart. An

injection directed forward into the hinder or renal part of one

of the postcardinal veins has been employed with more or less

success. In my opinion, however, injection by way of one of

the lateral veins possesses certain advantages Over either of the

other methods. : Bo

The injection of the renal division of the postcardinal vein is

objectionable for two reasons. In the first place, it is very dif-

ficult to dissect out the vessel. It lies under the peritoneum in

a loose mass of connective tissue, and unless the operator is

fairly skillful, the cannula is quite likely to be, pushed into lymph

370 THE AMERICAN NATURALIST. | (Vor. XXXIX.

spaces or into any opening other than the proper one. In the

second place, an injection mass entering by way of the renalend

of the postcardinal vein passes directly to the great thin-walled

cardinal sinus. No other veins can fill until the pressure in the

cardinal sinus has increased sufficiently to force the mass on into

the smaller and more remote spaces. This involves great dan-

ger of bursting the wall of the cardinal sinus. In practice, the

danger may be lessened by exerting external pressure upon the

sinus, either with the hand or by other means, so as to prevent

its becoming distended to its utmost capacity.

The venous sinus is a point more favorable for injection than

the postcardinal vein, so far as the filling of. the vessels is con-

cerned. If the injection mass is directed backward into one arm

of the venous sinus, the initial pressure of the fluid is exerted

almost directly at the ends of the several main venous trunks

which, other things being equal, stand equal chances of filling.

In practice, however, this method has been found objectionable

when attempted by an unskillful student (and since the fish is

usually the first animal injected by a student in comparative

anatomy, he is quite likely to be unskillful through lack of expe-

rience). The venous sinus is not very favorably situated for the

injecting operation. Great care is required lest the cannula be

pushed against the delicate wall of the sinus so as to rupture it.

Poor judgment in controlling the pressure on the syringe results

in the bursting of the sinus, and often the thin-walled auricle is

injured in the course of the operation. In the case of a prepa-

ration for demonstration or museum purposes, the cutting of the

venous sinus is, in itself, objectionable.

The difficulties which are met in the injecting of the postcar-

dinal vein or venous sinus are largely or wholly avoided by the

use of the lateral vein. The lateral vein is a large vessel extend-

ing along the entire length of the side wall of the abdominal

cavity and lying just beneath the peritoneum. It is conspicuous

in skates which have been dead not more than a day or two,

because of the blood contained in it. It is not necessary, as in

the case of the renal vein, to dissect out the vessel for injection.

The following method will be found practicable.

Open the abdominal cavity and note the position of the lateral

No. 462.) THE SKATE FOR ANATOMICAL STUDY. 371

veins. Then, at a region about midway of the length of one

lateral vein, and in a plane transverse to the long axis of the fish,

make an incision into the muscle of the lateral wall of the

abdominal cavity, carrying the incision across the lateral vein

and somewhat dorsal to it (see the figure, page 377). The

incision must be deep enough to admit of pressing apart the

masses of muscle either side of the cut in such a way as to make

easily accessible the two cut ends of the lateral vein. Immedi-

ately, then, before the loss of the blood contained in the vein

shall have made it difficult to see the vessel, thrust a probe or a

coarse bristle forward into the cut end of its anterior division

and another backward into its posterior division. A mass which

“ sets” quickly may be injected without tying the cannula into

the vein. For this purpose it is desirable to use a cannula of a

size sufficient nearly to fill the lumen of the vein. Such a

cannula, with the injection apparatus attached, may be inserted .

successively into the two cut ends of the vein and held firmly in

place with the fingers during the process of injecting. If it is

desired to tie the cannula in place, the muscle may be cut away

from around the cut end of the vein so as to leave about one

centimeter in length of the vessel projecting, with more or less

tissue attached to it. A ligature may then be passed around

this. small projecting mass of tissue, including the vein, and,

the cannula having been inserted, the ligature is tightened

upon it. :

The fluid which is injected into the anterior division of the

lateral vein passes directly to the corresponding precaval

(Cuvierian) sinus, whence it may pass into all the chief venous

trunks of that side except as impeded by valves. It passes also,

by way of the venous sinus, directly across to the opposite

precaval sinus, whence it may enter the vessels of that side of

the body. The cardinal and hepatic sinuses afford other, but

less direct, routes for the passage of the fluid from one side to

the other. In practice, this method usually results in the filling

of both lateral veins and at least the proximal ends of the several

brachial trunks. The mass fills also the postcardinal veins, in-

cluding their posterior inosculation, the hepatic sinus and veins,

the cardinal sinus, and the proximal ends of the inferior jugulars.

372 THE AMERICAN NATURALIST. > (VoL. XXXIX.

The precardinal veins, however, are rarely injected by this or by

any other method, except that of direct injection of each pre-

cardinal from its anterior end, —an operation which is not

practicable for anyone who is not familiar with the position of

the vein.

The filling of the cavities of the heart may be prevented or

controlled by means of ligatures tied around the heart in the

regions of the sinu-auricular and auriculo-ventricular apertures.

The injection into the posterior division of the lateral vein fills

the posterior connections of that vein, including the veins from

the pelvic fin (see Rand and: Ulrich, :05).

In brief, the advantages of injection va the lateral vein are as

follows: (1) the lateral vein is a sufficiently large vessel and

most easy of access; (2) its preparation for injection is a simple

operation, requiring no nice dissection nor other delicate tech-

nique ; (3) it is a relatively narrow and strong-walled vein, not

easily broken by the.point of a cannula, and capable of with-

standing the initial pressure of the injection ; (4) it conveys the

mass first to the precaval sinus, whence the chief vessels may

ll ; (5) the weak-walled cardinal sinus is remote from the point

of injection; (6) maximum filing of the systemic veins is

secured by a single operation.

An injection of the renal portal system is secured easily by

cutting across the tail at least four or five centimeters back of

the cloacal aperture and injecting forward into the caudal vein.

A taper-pointed glass cannula may be inserted carefully into the

cut end of the vessel and pushed in until the end of the vein is

tightly closed. During the progress of the injection the can-

nula must be held firmly in place.. When the cannula is with-

drawn, the escape of the fluid may be. poene by jamming a

bit of cotton into the end of the vein.

The hepatic portal system is best injected through the mesen-

teric vein. To secure a full injection upon the intestine the vein

must be injected backward as well as forward. Parker ('95,

P- 48) injects the duodenal vein, thus getting a complete injec-

tion at one operation. This is, indeed, an advantage. But, in

small skates, the greater size of the mesenteric vein, and the

fact that it is so much more accessible than the duodenal vein,

No. 462) THE SKATE FOR ANATOMICAL STUDY. 373

make the two-way injection of it usually less difficult to the stu-

dent than the single injection of the duodenal vein.

Injection Masses.— For the injection of the vessels of the

skate I have used an injection mass which is merely a slight

modification of well known masses, but one which may be found

to possess peculiar virtues for certain special purposes. Among

the injection masses suitable for purposes of gross dissection,

the cold or unboiled starch mass of Pansch ('77, '81; see Whit-

man, ’85, pp. 223-225) is doubtless best for general laboratory

use, especially where, in the case of a large class, many injec-

tions must be made rapidly. It is inexpensive, easy to use, and

gives results satisfactory for temporary demonstrations. It is,

however, not perfectly adapted for permanent demonstrations or

museum preparations, owing to the fact that it does not “ set" or

harden. The particles of starch remain in a discrete condition

so that, in the event of any injury to the wall of an injected ves-

sel, the mass may leak out and discolor the surrounding tissue.

The starch mass is poorly adapted for the injection of the ven- -

ous system of the skate because it is practically impossible, to `

dissect the thin-walled and irregularly shaped vessels without an

occasional slight injury, which gives rise to annoying leakage of

the mass.

Recently I had need of a mass which should acquire, after

injection, a fairly stiff consistency without becoming brittle,

which should not pass through capillaries, and which should

be convenient to use. Some modification of the gelatin method

seemed most likely to satisfy these conditions. A gelatin mass

with the coloring matter in solution, as ordinarily prepared, is

designed to pass capillaries. After some unsatisfactory experi-

ments with gelatin colored by means of pulverized carmine or

insoluble Prussian blue in suspension, it was suggested by Mr.

J. A. Long, who was working with me, that starch be mixed

with the melted gelatin to prevent its passing into the capillary

vessels. We had at hand a supply of the unboiled starch mix-

ture in several colors. The method which we used with success

at that time consisted in stirring into the melted gelatin about

one fourth its volume of the thick starch mass, which always

settles to the bottom of a jar containing the raw starch mixture.

374 THE AMERICAN NATURALIST.. [Vor. XXXIX.

Thus, the starch and the color were added both at once. In the

absence of the prepared starch mixture, a similar result may be

attained as follows.

Mix together some of the grocer’s pulverized cornstarch and

about one seventh its volume of a suitable finely powdered col-

oring matter (carmine, insoluble Prussian blue, chrome yellow,

chrome green). Add a little cold water to the mixture and con-

vert it into a thick paste. Into the melted gelatin stir one third

or one fourth its volume of the colored starch paste. The pro-

portions of the mixture may be varied, as occasions demand. I

have found the following formula convenient : —

Melted gelatin i | ; ; : . . 75 volumes.

Dry cornstarch . : ; : i QU > us

Dry color. : ee ; Saag

For non-histological purposes it is, of course, unnecessary to

use the finer grades of gelatin, such as photographic gelatin.

Any ordinary culinary gelatin serves equally well, besides being

always easily obtainable and less expensive. A mass of good

stiffness for injection purposes is obtained by using 1 gram of

dry gelatin to every 7 or 8 ccm. of water. If the vessels to be

injected contain much blood, the gelatin solution must be of

such strength that the mingling of the blood with it will not

prevent the hardening of thé mass. It is better not to inject

the veins of a skate immediately after the death of the animal,

for then the sinuses contain a large quantity of blood. If the

fish is kept in a cool place for about two days after death, the

greater part of the blood will have disappeared from the vessels.

At the same time, the walls of the vessels will have relaxed so

that the injection is more likely to pass into the smaller vessels.

This latter consideration is of more importance with reference

to the arteries than to the veins.

As regards the convenience of the starch-gelatin method, the

warming of the animal, preliminary to the injection, is unnec-

essary. The chief difficulty, therefore, which attends the gela-

tin method as ordinarily used for histological purposes, is

obviated. I have obtained good starch-gelatin injections of the

entire circulatory system of the skate, working in a room at

No. 462] THE SKATE FOR ANATOMICAL STUDY. 375

ordinary temperature (20° C.) without warming the animal above

the temperature of the room. The melted gelatin was slightly

superheated, and the heavy brass syringe, with rubber tube and

cannula, was heated by immersing in hot water to a temperature

about as high as consistent with comfort in handling. By these

means, the starch-gelatin was introduced into the blood-vessels

at a temperature considerably above its solidifying point. The

warm fluid penetrates into the smaller and remote vessels before

becoming cooled sufficiently to harden, giving quite as full an

injection of the finer vessels as the cold starch mass ever does.

The skates which I have injected with starch-gelatin were

immersed, immediately after injection, in three or four percent

formalin, which, having been freshly prepared with tap water,

was considerably cooler than the room temperature. The

starch-gelatin promptly solidified into a firm mass having the

consistency characteristic of stiff gelatin.

The starch-gelatin method described above gives results

entirely satisfactory for purposes of gross dissection. The

method may be used under any conditions where the unboiled

starch mass might be used, but where a mass of the consistency

of gelatin is to be preferred. The advantage of the starch-gela-

tin as compared with the raw starch lies in the fact that the

mixture “sets” and, therefore, will not escape, however much

the vessels may be cut. The advantage, for the purposes men-

tioned, of the mixture as compared with pure gelatin is in the

fact that the starch causes the mass to stop at capillaries, thus

preventing danger of the injection passing from one set of ves-

sels into another. Finally, the method is not a particularly

troublesome one, since the warming of the animal itself —

usually the greatest inconvenience attending the use of any

warm injection mass — may be omitted. The superiority of the

starch-gelatin is most marked in the injecting of a blood-system

containing large thin-walled sinuses, a$ in the case of the venous

system of the skate. Its advantages over plaster of Paris for

this purpose, are obvious and it is scarcely more troublesome to

use. :

The injection of the arteries of the skate is a comparatively

simple matter. The afferent branchial vessels may be injected

376 THE AMERICAN NATURALIST. [Vor. XXXIX.

through the arterial cone, as directed by Parker ('95, p. 48).

For the systemic arteries, Parker makes a single injection at the

duodenal artery. But, unless one is dealing with a large skate,

I have found it better to inject the anterior mesenteric artery

(see Fig. 1), in spite of the fact that it is necessary to inject it

backward (to secure an injection upon the intestine) as well as

forward. The greater size of the anterior mesenteric artery and

its accessibility, lying, as it does, along the very edge of the

mesentery, are advantages which more than offset the necessity

of injecting it both ways. As for details, such as the form of

the cannula and the manner of inserting it, I should consider

Parker's method applicable to a very large fish only. The cali-

ber of the anterior mesenteric artery in skates of small or

medium size is such as to require the use of a cannula with a

slender slightly tapering tip. By Parker's method, a cannula-

full of air is injected into the vessel. To avoid this, the cannula

should be attached to the syringe and filled with the fluid before

being inserted into the vessel.

In the accompanying figure of the skate I have indicated the

points at which the injections may best be made, to secure as

nearly as possible a complete injection of the blood vessels in

three colors. The mesenteric vessels are conveniently reached

by turning the stomach forward (so that, as the fish is viewed

from the ventral side, the dorsal aspect of the stomach is seen)

and pulling the digestive tube over to the animal's right side in

such a way as to stretch out flat the mesentery. The figure

represents the digestive tube in this position.

The several injections may well be made according to the

following plan. Whatever the order, the arteries should be

injected before the veins.

ARTERIES.

I. Arterial cone - -- --- forward - - - blue starch- pmp or Tagin

2. Anterior mesenteric forward - - - red

3. “ tt backward en © t « “

VEINS.

Hepatic Portal.

4. Mesenteric --...... forward - - - salen March gelain o ud Manet

MU CS E EKAE backward -

. 462] THE SKATE FOR ANATOMICAL STUDY. 377

The arrows indicate the points at

la is to be inserted.

aeg — The injecting of the blood vessels of the skate.

which the injections are to be made and the direction in which the cann

vein; . ; i

in; va. Z., lateral vein; vr. ms’enr., mesenteric vein.

378 THE AMERICAN NATURALIST. [Vor. XXXIX.

Systemic.

6. Lateral --------- forward - - - blue starch-gelatin.

c UM Gone ehe nece backward +; 9 E "

Renal Portal.

8. Caudal----------- forward -- yellow starch-gelatin or starch.

If it is desired to use gelatin for only the systemic veins, where

it is of greatest advantage, the arteries and the two portal

systems may first be injected with cold starch and then the

systemic veins with gelatin alone, for it is unnecessary to add

starch to the gelatin to prevent its passing capillaries when all

of the vessels beyond the system which is being injected are

already filled.

Are so many as eight separate injections necessary? My

experience has been that to decrease the number of operations

is to increase their difficulty and to render the results less satis-

factory. A mass injected into the systemic veins may pass

through the heart into the afferent branchial vessels. Yet I

have found it difficult to secure a full injection of the finer

afferent vessels of the gills except by injecting directly into the

ventral aorta itself. A perfectly fluid mass injected into the

hepatic portal vessels or into the caudal vein may be made to

fill the greater part of the venous system. But it is a great

advantage in the dissection to have the hepatic portal and renal

portal vessels distinguished from the systemic veins by a differ-

ent color. The difference in color serves to emphasize to the

mind of the student in a forcible way the nature of the relation

between the portal systems and the systemic veins. The sim-

plest way of securing the color difference is to inject each portal

system separately. All the systemic arteries may be injected

from the caudal artery at a single operation, but students suc-

ceed better with the two-way injection at the anterior mesenteric

artery. In short, it is better to make eight easy operations than

to make two or three of greater difficulty and less certainty.

No.462] THE SKATE FOR ANATOMICAL STUDY. 379

BIBLIOGRAPHY.

PANSCH, A.

"77. Kalte Injection mit Kleistermasse. Arch. f. Anat. u. Physiol.,

Jahrg. 1877, Anat. Abth., pp. 480-482.

PANSCH, A.

'81. Noch einmal die Kleisterinjection. Arch. f. Anat. u. Physiol,

Jahrg. 1881, Anat. Abth., pp. 76-78.

PARKER, T. J

'5. A Course of Instruction in Zootomy. (Vertebrata) London and

New York, xxiii + 397 PP-, 74 figs.

RAND, H. W., AND ULRICH, J. L.

: 05. Foui Connections of the Lateral Vein of the Skate. Amer.

Naturalist, vol. 39, pp. 349-364, 5 figs.

SMITH, H. M.

'98. The Fishes Found in the Vicinity of Woods Hole. Bull. U. S.

‘ish Commission, vol. 17, pp. 85-111.

WHITMAN, C. O.

'85. Methods of Research in Microscopical Anatomy and Embryology.

Boston, viii + 255 pp., 37 figs.

FOSSIL CRABS OF THE GAY HEAD MIOCENE.

JOSEPH A. CUSHMAN.

DuRING the summers of 1903 and 1904 the writer made two

trips to Gay Head for the purpose of obtaining fossils, espe-

cially those of the crabs so abundant there. The fossil crabs

are found in the greensand layer in close relation to the so

called *osseous conglomerate.' At the northern end of the

exposure, the crabs occur in a layer about six inches below the

conglomerate, which is itself at this point a very narrow band.

In this greensand layer which here is of a very dark, almost

blackish green color when first dug out, the crabs lie in a natu-

ral position in the bed. That is, the crabs are in a position with

their dorsal and ventral surfaces in the plane of the layer which

contains them. As the edge of the layer is here exposed in the

cliff and tilted at a very considerable angle, the edges of the

crabs are struck in digging them out. They occur in very hard

concretions, often entirely covered or as frequently, with a por-

tion of the carapace or legs showing at the surface. The shelly

portions of the crabs are decidedly black in color. The calcare-

ous matter is still left, however, and entirely dissolves with effer-

vescence in acid.

In another portion of the cliff, a short distance north of the

lighthouse, the crab layer slopes in the opposite direction and is

of a creamy white color.- The crabs and the material in which

they are imbedded are in consistency almost like cheese when

dug out. This material is so soft that it can be easily cut with

a knife. Upon exposure to the air the material quickly hardens

usually cracking considerably. The crab

and shrinks in drying,

in their details, the small

remains are here beautifully preserved

papillae on which the hairs are set being as per

have been in the living animal. -

In certain cases in the larger concretions, there are obt

fect as they could

ained

381

382 THE AMERICAN NATURALIST. (VoL. XXXIX.

remains which give a very good general idea of the crab as a

whole. These larger concretions also have the various parts

excellently preserved as will be noted in the description.

Dr. Edward Hitchcock was the first definitely to publish the

occurrence of the crab remains at Gay Head. He spoke of

them in his earlier reports on the geology of Massachusetts. In

the Final Report of 1841, he speaks as follows : —

“Crustacea. In the green sand at Gay Head we meet with

well-characterized specimens of the genus Cancer; although they

are in general much broken, showing that they originally be-

longed to a formation which was abraded or destroyed anterior

to the production of the green sand. The interior part of the

specimen consisted of argillaceous matter, probably containing

a large proportion of oxide of iron; but the covering of the ani-

mal still retains its black shining color, although apparently

carbonaceous. The broken state of nearly all the specimens,

renders it difficult to determine whether they belonged to more

than one species, although they probably did: and for the same

reason I have thought that drawings would not be of use."

In 1844, Sir Charles Lyell remarks at some length concern-

ing the structure and fossils of the Gay Head exposure, both in

the Proceedings of the Geological Society of. London 'and in the

American Journal of Science. In the latter (vol. 46, 1844, p.

319) he refers to the crab remains in the following words : —

“Crustacea. A species considered by Mr. Adam White as

probably belonging to the genus Cyclograpsus, or the closely

allied Sesarma of Say, and another decidedly a Gegarcinus."

In 1863, Dr. William Stimpson described Archeoplax signifera

from the Gay Head greensand and mentioned that there is an-

other species although he did not attempt to name it (Boston

Journ. Nat. Hist., vol. 7, PP. 583-589, pl. 12).

In 1900 (Proc. Amer. Acad. Arts and Sci., vol. 36, no. I, pp.

1-9, pls. 1-2), Professor Alpheus S. Packard describes a new

fossil crab, Cancer Proavitus, from Gay Head and gives a few

notes and several photographs of Archeoplax signifera Stimp-

son. 4

Specimens representing the latter species were especially

abundant in the material collected during the last two summers.

No. 462.] CRABS OF GAY HEAD MIOCENE. 383

These show many points of structure not heretofore described.

The material is in the museum of the Boston Society of Natu-

ral History, and is referred to by number. The material at the

Museum of Comparative Zoölogy at Cambridge was also studied

and is also referred to as well as one or two specimens in the

teaching collection of the Paleontological Department of Har-

vard University.

Archzoplax signifera Simpson.

Archeoplax signifera Stimpson, Boston Journ. Nat. Hist., vol. 7,

no. 4, April, 1863, p. 584, pl. 12, figs. 1-4; Dall, Amer.

Journ. Sci., vol. 48, 1894, p. 297; Packard, Proc. Amer.

Acad. Arts and Scis vol. 36, no. 1, July, 1900, p. 7, pl. 1,

fig. 4, pl. 2, figs. 1-3.

Carapace.— In the specimens the length of the carapace

varies from 1 to 2.5 inches, in greatest breadth from 1.2 to 2.75

inches, and in posterior breadth from 0.75 to 1.8 inches. The

superior outline along the median antero-posterior line is decid-

edly curved as noted by Stimpson. This is shown in an outline

side-view of a typical carapace (Pl. 1, Fig. 1). A similar view

in the median line (Pl. r, Fig. 2) shows at the slope at the sides

and the depressions at each side of the median portion. The

surface of the carapace is smooth, finely punctate or granular,

the coarser granulation being in definite portions of the central

region as well as of the anterior and lateral regions. The color

pattern of the carapace is very well made out in several speci-

mens. In the great majority of the specimens it is shown by a

difference in smoothness and in luster of the surface, but may

be seen as black markings against d dark gray background, as

in Pl. 2, Fig. 3, or best of all on the under side of the upper

surface as black markings on a very light brownish white back-

ground (Pl. 2, Fig. 4). Here the. markings stand out with

remarkable clearness. There is considerable variation in the

markings of this species but all follow the same general pattern.

The central lunate markings are important as a means of orient-

ing any large or small part of a specimen of this species which

384 THE AMERICAN NATURALIST. | [Vor. XXXIX.

shows them. The variation in the central markings is shown

in the two figures. In certain specimens examined the two

sides of the same specimen varied much from each other.

As a whole the carapace is quadrangular, considerably broader

in front than behind. The front angles have four teeth as

described by Dr. Stimpson. Three of these are large, the first,

second, and fourth, while. the third is decidedly smaller. The

orbits, as described, occupy about one third the breadth of the

front of the carapace. The border is entire and raised, and is

composed of crowded granules.

The front is nearly one fourth the width of the carapace and

has a somewhat different form from that figured by Dr. Stimp-

son as a comparison of the figures will show. Excellent speci-

mens of this part were obtained showing the complete form.

There are two lateral lobes on the anterior border and a median

lobe which is cut on the median line, making it emarginate.

The front as a whole is bent downwards as shown in Pl. rn Fig.

I. In the restoration it is drawn as though slightly raised to

give its true shape (Pl. ı, Fir.

In the specimens broken from large concretions the eyes

have very frequently been excellently preserved. They have a

prominent basal joint, with an expanded cylindrical outer portion

of the shape shown in the figure. It seems strange that Dr.

Stimpson did not obtain good specimens of the eyes for they :

have appeared very frequently in the collections of the last two

summers.

Of the antennz little was made out except their position

which is but very slightly anterior to the base of the eyes.

The bases of the antennze appear as cross sections and as small

bits now and then.

One specimen (Pl. 2, Fig. 5), showed the pair of antennules

extending slightly beyond the front, but here again it was impos-

sible to make out much more than their presence and position.

Turning to the ventral side, almost the entire features bave

now been made out and are included in the synthetic figure (Pl.

2, Fig. 6). The sternum is excellently preserved in a consider-

able number of specimens. A cast from the white layer showing

all the minute tubercles was obtained (B. S. N. H. no. 12,977).

No. 462.] CRABS OF GAY HEAD MIOCENE. 385

In drying, this specimen has cracked considerably. As a whole

the sternum is nearly a plane surface except where it is hollowed

in the center to receive the abdomen. The anterior portion,

triangular in shape, is usually well separated from the rest. It

varies considerably in size and shape. The main part of the

large anterior plate is divided into three parts by a Y-shaped

combination of sutures as seen in the figure. This is an incom-

plete division but the sutures are nearly always in evidence.

As noted by Dr. Stimpson the “male genital tubercles are

found on the posterior margin of the second segment. These

are situated just within the edge of the abdomen so that they

are covered by it.

Dr. Stimpson found the abdomen of the male only, but in the

collections of the past two years there are a few specimens of

the abdomen of the female. The males appear to have been

much more common. The male abdomen is approximately as

figured by Dr. Stimpson, none of the segments being fused.

A figure of the female abdomen is given (Pl. 2, Fig. 10). The

third joint from the end is the widest, and there is an abrupt

tapering from it toward either end. Of the abdominal append-

ages but one specimen, and that very incomplete, has appeared

(Pl.2, Fig. 11). This specimen indicates at least two pairs of

these appendages.

One specimen (Pl. 2, Fig. 12) shows a cast of the outer max-

illiped from which a fairly complete idea of these appendages

may be obtained. Several other specimens show the basal

joints in place and the minutely tuberculated surface (Pl. 2,

Fig. 9).

The front legs are shown in a number of specimens, the basal

and outer joints being those most frequently preserved. The

teeth on two of the joints as figured by Dr. Stimpson, were not

made out. The chele have a series of alternating teeth alike

in both the left and the right sides. The various joints were

more or less ornamented with a color pattern, portions of which

are well preserved in a number of specimens. The teeth and

the tips of the chelz are much lighter colored than the other

portions. The portion of the shell about the base of the anterior

pair of legs has a raised beaded edge. This portion is often

broken away and variously placed in some of the specimens.

386 THE AMERICAN NATURALIST. | (Vor. XXXIX.

Of the posterior four pairs of legs we have with the help of

one specimen obtained in 1904 (Pl. 2, Fig. 2), a knowledge of all

the parts. This specimen had the last four joints of a single

leg very well preserved. The main characteristic of these

appendages is the great length of the fourth joints. These

joints are considerably flattened in some cases but usually

appear in cross section as shown in Pl. 2, Fig. 13.

Certain of the specimens preserved in the concretions show

the internal characters very well. The doubly triangular skele-

tal mass shown in Pl. 2, Fig. 5, is often seen perfectly preserved.

The divisions of the posterior part of the body are also seen in

the same figure. In rare cases the gills are found lying in their

cavities. In one case a small piece was taken out, softened and

mounted. In this condition it showed the tubes and something

of the structure of the gill. Apparently it was simply dried and

not in any degree impregnated by mineral matter. A small rod-

like mass is often seen when the front is broken away exposing

the interior.

Altogether it seems that we now have a very fair knowledge

of this Miocene species. In PI. I, Fig. 3, is given a restoration

of this species from the specimens studied.

Cancer proavitus Packard.

Cancer proavitus Packard, Proc. Amer. Acad. Arts and Sci., vol.

36, nö. 1, July, 1900, p. 4, pL n Bes 1-2, ‘

Of all the specimens examined there seems to be but one

which is in any way referable to this species. This specimen

from the white leached layer already mentioned, consists of the

cast of the sternum, abdomen, and outer maxilliped of a small

female individual. Its main characters are shown in Pl. 2, Fig.

14. From a study of the type the specimen is referred to this

Species as it seems to be a Cancer and is from the same bed as

was the type of this species. The type was a male and this is

in all probability a small female of the same species. It will be

at once seen that it cannot be referred to Archzoplax, which has

No. 462.] CRABS OF GAY HEAD MIOCENE. 387

a very different sternum, abdomen, and outer maxilliped from

that shown in the specimen under discussion. This species rep-

resented by the male specimen and the hand originally described,

and now by this cast of the under side of a female, shows that

it must have been far less common than the Archzeoplax.

Further search, however, should yield more specimens of this

species. I am greatly indebted to Dr. Walter Faxon of the

Museum of Comparative Zoólogy for help in placing this speci-

men in its present position, for although its condition would not

give its complete relations there was nothing to preclude its

being a Cancer.

Many of the Archzoplax had specimens of Balanus concavus

Bronn attached to the carapace, as has been already noted in a

previous paper.

Boston SOCIETY OF NATURAL HISTORY,

March, 1905.

EXPLANATION OF PLATES

PLATE ı. Natural size.

FiG. 1. Outline of side vie

Fic. 2.

Outline of front view of sec sction deis middle of oe

G. 3, Restoration of 4 rcheoplax signifera, dorsal

PLATE 2. $ natural size.

Fic. 1. Ventral view, sternum and i joints of = leg (B. S. N. H. no. 12,946).

Fic. 2. Last four joints of one of the walkin legs (B. "n N. H. no. 12,944).

Fic. 3 olor pattern of one side of Pa (

Fic. :

S.N. 12,969). X 21.

Fic, 5 ecimen vies open showing antennules, plates of interior, and double triangular

plate (B. S. N. H. no. 12,945).

IG. 6. aic re from ventra

Fic. 7. Portion of hand and finger with teeth (B. S. kg H. no. 12,941).

1 ortion of two digne ie broken (B. S. N. H no. 12,942).

*9. Ventral vie stern abdomen, maxilliped, basal joints of legs and portion of

2 (M.C.Z

FIG. 10 Abdomen of female (B H.n 940).

Fic. r1. Specimen showing FERN eke. (B. S. N. H. no. 12,943).

Fic. 12. Outer maxilliped of right side (B. S. N. H. nO. 12,947).

Fic. 13. Outline of section of one of the rear

Fic. 14.

ancer proavitus, oo. »f abdomen, sternum, maxilliped, and basal joints of two

legs (H. S. N. H. no. 12,970).

389

CRABS OF GAY HEAD MIOCEN

No. 462.]

Ole m un

Lu»

PLATE :.

THE AMERICAN NATURALIST. [VoL. XXXIX.

390

PLATE 2.

CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF

THE MUSEUM OF COMPARATIVE ZOÖLOGY AT HAR-

VARD COLLEGE. E. L. MARK, Director. No. 167.

A CASE OF ABNORMAL VENOUS SYSTEM IN

NECTURUS MACULATUS.

THEODORE H. ROMEISER.

Ix all classes of-vertebrates variations in the morphology of

the circulatory system are by no means infrequent. Indeed, one

rarely, if ever, finds two individuals with precisely the same

arrangement of the blood.vessels. Even in cases in which the

vessels are for the most part symmetrical, the smaller vessels,

particularly the veins, are found to vary more or less on opposite

sides of the body, as is readily shown by a comparison of the

superficial veins of one's own forearms Or the backs of the

hands.

The literature on abnormalities of the blood-vessels shows that

they often may involve even the largest and most important

veins of the body, such as the postcava and its tributaries. It

has been observed that in the venous system of some verte-

brates the cases of variation are more frequent than those of

the “normal” condition. Thus McClure (:004) finds variations

in the opossum of such frequent occurrence and of so definite a

character as to suggest probable phylogenetic relations.

The literature on abnormalities of the veins in Urodela shows

records of several cases, mostly in European salamanders.

Hochstetter ('88, p. 164) describes a condition in Salamandra

maculosa in which the postcava did not pass through the liver,

but was continuous with the much enlarged right posterior car-

dinal vein, the two forming a single vessel passing straight to the

venous sinus. He also briefly mentions similar abnormalities

seen in specimens of Szredon pisciformis. ue

Joseph (:01) observed in Salamandra maculosa à similar case,

391

392 THE AMERICAN NATURALIST. . (Vor. XXXIX.

in which, however, it was the left cardinal that was hypertro-

phied. In another case (also S. maculosa) described by Joseph,

there were two abnormally large, symmetrical veins on the ven-

tral surface of the liver, one on each side of the suspensory

ligament. (Normally, according to Hochstetter, there is but one

large hepatic vein, which is in the left half of the liver.) They

ended separately in the venous sinus, which was, in his opinion,

the enlarged end of theleft vein. The right vein he found con-

tinuous with the postcava within the liver. According to his

description and figures, the postcava entered the dorsal surface

of the posterior end of the liver, passed forward through the

liver substance, as it does normally, then became continuous

with the right superficial vein ventrally, near the junction of the

anterior and middle thirds of the liver.

The following anomaly was observed in the veins of a speci-

men of JVecturus maculatus injected for dissection of the vascular

system. The work was done in connection with the course on

comparative anatomy given by Dr. H. W. Rand at Harvard

University. Although annually for some years past many of

these amphibians have been used for dissection and injection, no

similar condition has been noted. This case is of interest, not

only on account of its rarity and the profound alterations involv-

ing the chief veins of the body, but also because it is, so far as

I know, the first instance of the kind observed in Necturus.

Moreover, it differs markedly from all similar cases previously

reported. Before giving an account of this abnormal condition,

it may be well to describe briefly the normal arrangement of the

corresponding veins.

The postcava (Fig. 1) begins as a median trunk lying between

the kidneys; passes anteriad ventral to the aorta, which it leaves

at a point near the posterior border of the liver ; bends ventrad

to enter the dorsal surface of the posterior end of the liver,

through which it passes anteriad and within which it receives

the hepatic veins ; emerges on the ventral surface of the ante-

rior end of the liver ; bifurcates, then reunites and ends in (or

rather is continuous with) the venous sinus at the point where.

the ducts of Cuvier enter laterally. The right and left posterior

cardinals arise from the convexity of the bend in the postcava

No. 462.] ABNORMAL VEINS IN NECTURUS. 393

dt. Cuv. sn. vn. sn. UH.

JU. ...

PEN sb. clav.

hp. MB:

-- vn hp.s. po DN. rp. s.

wer:

Ber...

vn. hp. dx. ----k---- 0: P eav.

vn. hp. dx. --

pcr. dx. -—

per.dz.?-

pte m.

me p'cav. -

Fıc. ı. FIG. 2.

the venous system of Necturus maculatus seen

i own dısplaced

The figures represent the central portion of

about one half natural size.

rom the ventral side and are

slightly to the left of the median plane. Fig. ı represents the no

ithin the liver being indicated by broken lines Fig. 2 the attachment o sus-

pensory ligament is indicated by a broken line. d£. Cuv., duct of Cuvier; Af., liver;

jug., jugular vein; f'cav., postcava ; p'cr. t posterior cardinal vein ; ‚left

posterior cardinal prs * Mittelstiick " of postcava; s v., subclavian vein;

vn. hp. s., left hepatic vein.

vn., venous sinus ; v. Af. dx., right hepatic vein;

394 THE AMERICAN NATURALIST. [Vor. XXXIX.

where it leaves the aorta, and they pass anteriad to terminate in

the corresponding ducts of Cuvier, close to the venous sinus.

The cardinals may arise from the postcava either separately or

by a short common trunk. According to Miller (:00), the latter

condition is the more usual. Posteriorly the cardinals anasto-

mose with the renal portals, which have been omitted from the

figure as not bearing upon the abnormalities here considered.

The hepatic veins are variable in number, size, and termination ;

but Miller finds that two are larger and more constant than the

others. One joins the postcava near the center, the other at

the anterior end, of the liver. It is to be noted that in .Sa/a-

mandra maculosa there is normally but one large hepatic vein,

which is in the left half of the liver (Hochstetter).

In the abnormal case (Fig. 2) the postcava arose normally

between the kidneys, but instead of entering the liver, it became

continuous anteriorly with a large and apparently median vessel

which passed directly anteriad along the dorsal body wall to the

heart, without receiving any hepatic veins. The end toward the

heart lay somewhat to the right of the median plane and entered

the venous sinus from the right side. The hepatics were two .

very large symmetrical veins, superficial on the ventral side of

the liver for their entire length, one on each side of the suspen-

sory ligament. They united at the anterior end of the liver to

form a short, bulbous trunk, the anterior end of which was

directly continuous with the venous sinus. The left hepatic

vein was fairly straight and arose from the posterior end of the

liver, where it received a small superficial tributary from the

right side of the posterior border. The right one, of about the

same size, was more irregular in its course. Its beginning was

imbedded in the substance of the liver on the right side of its

posterior extremity. Both received small hepatic branches

within the liver, as was shown by sectioning.

About one centimeter posterior to the venous sinus and to

the left of the median plane, there arose from the body wall a

small vein formed by the union of two short branches. In its

course posteriad it gradually approached the large median vein

described above and passed along its dorsal surface, to which it

was intimately attached. Its size increased slightly as it passed

No. 462] ABNORMAL VEINS IN NECTURUS. 395

posteriad. By careful dissection it was separated to a point

opposite the posterior extremity of the liver. Here it was unin-

tentionally severed from the postcava at what is believed to

have been its point of entrance, as it could not be traced any

farther. Its junction with the postcava could not be determined

positively on account of its small size, the injury to the delicate

wall of the postcava, and the exudation of the injected starch

mass. The identity of this vessel is open to question, but from

its relations and course, and by analogy with the somewhat

similar cases mentioned above, it was most probably the atro-

phied left posterior cardinal corresponding to the very much

hypertrophied right posterior cardinal, which was functioning as

the anterior part of the postcava.

No further abnormalities were observed in either the circu-

latory or other systems. ;

Comparing this case with the normal venous system and con-

sidering the development of the postcava, it is inferred that the

right hepatic vein (or at least the anterior part of tt) represents

the anterior part of the normal postcava, the normal “ Mittel-

stück” of the postcava having failed to develop. Wiedersheim

('98, p. 371), speaking of the development of the postcava in

Amphibia, says: * Der vordere (Leber) Abschnitt entstammt

offenbar zum Theil der rechten V. omphalo-mesenterica, zum

Theil aber entsteht er unabhängig.” Hochstetter (88) states

concerning the development of the postcava in Salamandra :

*Das Wesentliche an der Hohlvenenbildung ist demnach die

Verbindung zwischen Lebervenen und Cardinalvenen und die

Verschmelzung der Cardinalvenen in ihrem Urnierenabschnitte "

(p.105); ,... "due Verschmelzung erfolgt übrigens erst ziem-

lich spát,.nachdem der sich ganz selbständig entwickelnde

Abschnitt der vorderen Hohlvene sich mit der rechten Cardi-

nalvene in Verbindung gesetzt hr "(p 103), Aus

nahmsweise kommt es manchmal vor, dass die Entwicklung

eines vorderen Hohlvenenabschnittes vollständig ausbleibt, dann

bildet sich entweder die rechte oder linke Cardinalvene weiter

aus und führt im erwachsenen Thiere das Blut der Nieren,

Geschlechtsorgane und des Rumpfes dem Herzen zu” (p. 164).'

In comparison with the abnormal cases previously described,

396 THE AMERICAN NATURALIST. [Vov. XXXIX.

this case of Necturus possesses in the hypertrophied right pos-

terior cardinal, the characteristics of one of Hochstetter’s, and

in the two large symmetrical hepatic veins, those of one of

Joseph’s, although, upon the whole, it is strikingly different

from both.

BIBLIOGRAPHY.

HOCHSTETTER, F.

'88. Beiträge zur vergleichenden Anatomie und Entwicklungsgeschichte

des Venensystems der Amphibien und Fische. Morph. Jahrb.,

Bd. 13, pp. 119-172, Taf. Il-IV, 7 Textfig.

JOSEPH, H.

- Ueber zwei Abnormitäten im Venensystem von Salamandra macu-

losa Laur. Anat. Anz., Bd. 20, pp. 283-293, 4 text figs.

MCCLuRE, C. F. W.

:00. On the Frequency of Abnormalities in Connection with the Post-

caval Vein and its Tributaries in the Domestic Cat (Felis domes-

tica). Amer. Nat., vol. 34, pp. 185-198, 9 text figs.

MCCLURE, C. F. W

:00a. The Variations of the Venous System in Didelphys virginiana.

Anat. Anz., Bd. 18, pp. 441-460, 21 Text figs.

MILLER, W. S.

00.

The Vascular System of JVecturus maculatus. Bull. Univ. Wis-

consin (Sci. Series), no. 33, pp. 211—226, pls. 9-11.

SLONAKER, J. R.

A Strange Abnormality in the Circulatory System of the Common

Rabbit (Lepus sylvaticus). Amer. Nat., vol. 34, pp. 639-640,

1 fig.

WIEDERSHEIM, R.

, Grundniss der vergleichenden Anatomie der Wirbelthiere. 4te,

Aufl., Tena, xxiii + 559 pp-

SIR CHARLES BLAGDEN, EARLIEST OF RHODE

ISLAND ORNITHOLOGISTS.

REGINALD HEBER HOWE, JUNIOR.

I was interested, when compiling the Rhode Island, Massa-

chusetts, and Vermont State lists, to notice the date of the first

authentic record for any bird within the States named. The

earliest Massachusetts record was of the Black Skimmer (R/yx-

chops nigra) recorded in 1605 in the Voyages of Samuel de

Champlain. The Vermont list contains accounts of observa-

tions made in 1794, by Samuel Williams, while the Rhode

Island list dates from the writings of Edward A. Samuels in

1867. The ornithological literature of the State of Maine dates

from the History of that State by William D. Williamson, pub-

lished in 1832; that of New Hampshire from the work of

Jeremy Belknap in 1792 ; and that of Connecticut from early in

the nineteenth century. That Rhode Island has always been

neglected is evidenced by the minimum of literature and the lack

of material from the State, in all the collections of the country.

Through the kindness of Mr. William Brewster, I have lately

received a copy of the Bulletin of. the New York Public Library

(vol. 7, no. 11, Nov., 1903, pp. 407-446), containing a number

of letters from Sir Charles Blagden to Sir Joseph Banks, written

from 1776-1780.

Sir Charles Blagden, physician, was born on April 17, 1748.

He graduated from the.University of Edinburgh, and entered

the army as a medical officer, remaining in service until 1814.

During the Revolution he was stationed at Charleston, Reedy

Island, Delaware, New York, and Newport. He wason intimate

terms with Cavendish, the famous chemist, who bequeathed him

£16,000. He was also a friend, for fifty years, of Sir Joseph

Banks, president of the Royal Society, and he himself was

elected secretary of this Society in 1784. He has been de-

Scribed as a *careful worker in physical research," and Dr.

397

398 THE AMERICAN NATURALIST. | (Vor. XXXIX.

Samuel Johnson, according to Boswell, called him “a delightful

fellow." In 1789, he was elected a correspondent of the

Académie des Sciences of Paris. On March 26, 1820, he died

at Arcueil, Paris, at the home of his friend Berthollet, the

renowned chemist.

Sir Joseph Banks was born on February 13, 1743. He

attended Harrow and Eton where he was early interested in

botany. He afterwards entered Christ College, Oxford, where

he became interested in general natural history. From 1768

until 1771, he fitted out and accompanied Cook's expedition on

board the * Endeavor.” He died at Isleworth, June 19, 1820,

and his collections and herbarium were finally placed in the

British Museum, where it is not improbable some of the Rhode

Island animals collected by Blagden, were sent.

One of the letters under date of October 28, 1777, states that

the specimens were sent to Europe on “the Brigantine Betsy, a

Navy Victualer" in *twelve Kegs” “preserved in Rum” and

Blagden writes: “Upon my appointment to the employment

which brought me hither, Mr. Barrington desired that I would

collect what things fell in my way for the use of his friend Mr.

Lever. After considering as maturely as I could what would

best answer everybody's purpose, I thought that desiring you

& Mr. Barrington to accept the collection jointly between you,

would be the properest step. Mr. Lever! wants anything that

he happens not to have in his Museum, whether it tends to illus-

trate Science or not; on the contrary nothing can be an object

to you but what will conduce to the improvement of Natural

History as a branch of Philosophy T qur All my apprehensions

are, lest the coolness which has subsisted between you & Mr.

B. should make this division unpleasant; but if it be possible,

wave that on the present occasion out of your friendship to me ;

if it be not possible, the last resource is, that you will each be

so kind as to take six kegs apiece: At the same time consider,

that at least 19 out of 20 of the things sent must be mere

1S8; : :

Sir Ashton Lever “expended an immense fortune in the formation of....

the Leverian Museum” near Manchester, which later was removed to London,

and was finally sold “by way of lottery ” in 1785, to a Mr. Parkinson, who sold

it by auction in 1805.

No. 462.] SIR CHARLES BLAGDEN. 399

trumpery, fit only to be thrown upon the dunghill ; for I took

all that offered.” Under date of March 2, 1778, Philadelphia,

he again writes: “ With respect to the Kegs from Rhode-Island,

I should deem myself extremely unfortunate if they occasioned

the least misunderstanding between you & Mr. Barrington,

more especially as I am convinced that they scarcely contain

anything worthy your attention ; it would be extremely easy to

divide them by your taking six apiece; but as Mr. Barrington

had previously acquainted me with his intention of sending all

that he should receive to Mr. Lever, I thought it would best

answer both his purpose and yours, that he should give up to

you every thing that was nondescript, (if there be any such) on

condition of keeping all the remainder, among which there might

be many specimens not yet in Mr. Lever's Museum, & there-

fore interesting to him though not to you."

Two of the letters — the first dated September 12, 1778, the

second undated — contain an annotated list of animals collected

in Rhode Island, which were sent home, evidently, by Sir

Charles Blagden to Sir Joseph Banks in Europe. The number

and sex of the specimens were curiously designated in the fol-

lowing manner: “A string is tied to some part of the animal

with its two ends of a length suited to the number to be

expressed ; every single knot on either or both of these ends

stands for a unit; every double knot, that is, two single knots

close together, stands for 10; and a /oop at one end of the

string means 100. .... Where I gota male & female the knotted

string was tied to the right leg of the former & to the left leg of

the latter." |

The birds, which are the subject of this paper, were collected

in Rhode Island, and most of them are to be positively identi-

fied from the names and descriptive notes. Many of the ver-

nacular names he used are still in use in the State as local

cognomens of species; e. g, wamp, for the Eider (Somateria

dresseri).

Under date of April 10, 1779, New York, he again writes

that a Captain Davies *seems to have got every thing " in this

country “that was brought to me in Rhode Island, except the

Scapog-bird mentioned in my catalogue, which, I believe, he

never saw."

400 THE AMERICAN NATURALIST. (Vor. XXXIX.

Of the seventy-nine birds listed, the following species, I con-

clude, are almost unmistakably indicated by Sir Charles Blagden.

Only the notes as to their comparative abundance are given.

Liu.

I. “No. 2," “ Diver” or “Loon” = Gavia lumme; “Feb.

18."

2. “No. 3,” * Sparrow-Hawk" or “ ee Falco

Martens probably, from date of capture. ‘ Feb. 20.’

A “No. 4," * yellow-Bird ” — — Astragalinus tristis. “Feb.

^ also * Apr. 15’?

e “No. 5," * Blue-Bird " — Sialia sialis. “ Mar. a

5. “No. 6,” “No. 42,” and “No. 94,” “ Red-winged Black-

bird” = Agelaius pheniceus; “male.... appeared here the

Loth or 12th of March: in a fortnight or three weeks came the

females.” ;

6. “No. 7," * Robin" — Merula migratoria; ‘arrive.

about the middle of March, & in such quantities & so tame, that

a dozen could be shot in an hour within two miles of the town."

2." NA. i " “yellow Woodpecker” = Colaptes auratus luteus.

Mar. 197

8. “No. 9," * Hildee” = Oryechus vociferus: “March 24.”

9. “ No. 10,” “Snipe” — Gallinago delicata. “ Mar. 24.”

IO. “No. 12," “Wamp” = Somateria dresseri. “Mar. 25"

and * Ap. 9."

It. "No. 13," * Red.billed Coot” — Oidemia americana.

“Mar. 35,"

12. “No. 14,” and “No. 15"? “Beach-Bird, or Snipe

Beach-Bird " = Calidris arenaria. « Mar. 25.”

13. "No. 16,” * Marsh-Quail " — Sturnella magna. “ Ap.

; 14. “Great: Loon ^ = Gava imber; one was shot * April

the 5."

15. “No, 17" and « No. 28," “ Bald-pated Coot” = Oide-

mia perspicillata, “ Ap. 3:

16. * No. 18" and * No. 23, " “Old Wife” — Harelda hye-

malis. “ Ap. 3" and « Ap. 8

No. 462.] SIR CHARLES BLAGDEN. 401

17. “ No. 19,” ‘Sheldrake’ = Merganser serrator. “ Very

niesty." Au 37°

18. “ No. 22,” “ Parrot-Bill,” * Noddy: or “Murr” = Aka

torda ; “a rere bird here!’ * Ap. 10.”

I9. “No. 24,” Dipper = Zrismatura jamaicensis ; “very

common.” ^* Ap. 8.”

- 20. “No. 25,” ** Loon "s Commius aursius. € Ap 8.

21. “No; 25," * Brant" = Branta berniela, “in Spring,

with a southerly wind, prodigious flocks pass close to Sachawest

pont. SADT

22. “No. 29," * White-wing " = Ozdem:a deglandi. “Ap.

23. “No. 30,” “Crow Black-bird " = Quiscalus quiscula +

aeneus. “ April.”

24. “No. 33,” “Cormorant” = Phalacrocorax auritus or

carbo, perhaps both. “Harbour in large quantities on a rock

about 2 miles from Sachawest Point, thence called Cormorant

Rock. Apr 22}

25. “No. 35,” “Common Swallow” = Hirundo erythrogas-

ter; “Ap 23%: i

26. “No. 37," * Pewit " = Actitis macularıa.

27. “No. 40,” ‘Grass-Plover” = Bartramia longicauda.

Perhaps Charadrius dominicus? ‘They come in great num-

bers & are very tame at first, but grow extremely shy & and

hard to shoot in a few days. Ap. 29.’

28. “No. 43," “ Woodcock” = Philohela minor; “ there are

Woodcock's nests in woods of most of the Islands round Rhode

Island." “May 6."

29. “No. 46," * black-breasted Plover ” = Squatarola squa-

tarola. “Lately migrated to the Island ; in flocks. May 9."

“ May 16.”

30. “No. 47,” and “No. 61,” “ Tell-tale Plover,” “ yellow-

legged Plover” — Totanus melanoleucus. “May 11 "and

“ May I gj" "

31. “No, 48," **Oxeeye " = Ereunetes pusillus **begins to

come in large flocks to the ponds near the beach May 1 Lh |

32. “No. 49," *ring-necked Plover” = Z"Egialitis semipal-

"mal * May If

402 THE AMERICAN NATURALIST. [Vor. XXXIX.

33. “No. 50," * King-bird" = Tyrannus tyrannus. “May

12."

34. “No. 51," “Quongquéedle” = Dolichonyx oryzivorus.

“The males appear some time before the females, — which

then appear all of a sudden & pair immediately." « May 13."

35. “No. 54," “common Chipbird " = Spizella socialis.

* Frequenting the gardens April 23d."

36. “No. 55” and “62,” and “67,” “ Rock-Plover," *red-

legged Plover,” * Whale-Bird " = Arenaria interpres. “ May

13. May is. "May 16.”

37. “No. 57," = Empidonax minimus. “ Frequent in gar-

dens. May 13 & 16.”

38. “No. 58," “ Thrasher or Thrush ” = 7oxostoma rufum.

“Pretty common.” “May 13.”

39. “63,” “Mosquito Gull” — Sterna antillarum; “ very

frequent about ponds near the beaches." « May 15" (see text

following ** No. 102”). “July the 2d I shot a Mosquito Gull

No. 63 with the Minow No. 45 in its mouth, which it was tak-

ing to the young. then hid in the sand near the beach."

40. "63," “ Humming-Bird " = Trochilus colubris. “May

r”

41. “68,” “common wild goose " — Branta canadensis.

42. “69,” “ Night-Hawk " = Chordeiles virginianus ; “very

common.” “May 16.”

43. “No. 70,” “Wren” — roglodytes aédon; “found about

shrubs in gardens.” “May 16.”

44. "72," “Cat-bird” = Galeoscoptes carolinensis. “ May

I T

45. “No. 73,” “Fool Plover” — Macrorhamphus griseus.

Fool Plover is to-day a local name for this species. “May 20.”

46. “75” and * No, 96," *Shike-poke" or * Quawk" =

Nycticorax nycticorax nevius. « May 22" and “June r9."

Perhaps the former name refers to Butorides virescens, but it is

universally called in the State « Fly-up-the-creek.”

47. "76, Mackarel Guil" = Siena hirundo. “May 24."

48. **80," “red-headed Woodpecker ” — Melanerpes erythro-

cephalus. Perhaps Sphyrapicus varius. “June 1.”

49. “82,” “common crow " — Corvus brachyrhynchos.

No. 462.] SIR CHARLES BLAGDEN. 403

50. “No. 87," ‘American Cuckoo” = Coccyzus erythroph-

thalmus ; probably, because the more common. “June 15."

51. “No. 9o," “Tree Heron” = Nyctanassa violacea ; * very

rare. "Tue li

52. “No. 91,” “Chimney Swallow” = Chetura pelagica ;

“more common in the inland parts than near the seacoast.”

“Jone T$."

53. “No. 92," “Fulica Chloropus "— Gallinula galeata ;

“very rare." Jun. 16."

54. “No. 93," “Whistling Quail" = Colinus virginianus ;

“common.” “Found all the year."

55. “No. 97,” “Bank Swallow” = Riparia riparia. “June

56. “No. 103,” * Whipperwill” = Antrostomus vociferus.

57. “No. 105,” “wild Pidgeon” = Ectopistes migratorius.

“Jul. 7.” Evidently about June 19 “some flights ....came

over the Island, but the great flocks are not found nearer the

sea than Providence."

58. “No. 107,” “Gull,” “ Sterna nigra” = Hydrochelidon

nigra surinamensis. “ Jul. 14.”.

59. “No. 108,” “Kingfisher " = Ceryle alcyon. “ July 14.”

60. * Broad-bill " = Aythya marila.

Or DovusBTFUL RECOGNITION.

1. “No. 1,” “Common Sparrow” = Spizella monticola or

Melospiza cinerea melodia. “ Feb. 18.”

2. “No. 12," “Whifsjtling Diver” = Clangula clangula

americana?; “coarse species of the Sea Wild Duck, very com-

mon. Mar. 25.”

3. * wood-pecker ” or “ Picus hirundo "= Dryobates pubescens

medianus? Seen * April the 8th."

4. “No. 26,” “Loon” or “ Colymbus Immer ” = Gavia

lumme? “ Ap. 13? “Weighed three pounds.”

5. “No. 32," * wood-pecker" =? “ Ap. 17."

6. “No. 34,” “ Ground Sparrow ” = Spizella pusilla? “ Ap.

23.” “Chirps, cannot sing." It is interesting to note that

Wilson did not know the Field Sparrow's song.

404 THE AMERICAN NATURALIST. Wor. XXXIX.

7. “No. 36," “common Swallow” = /ridoprocne bicolor?

«Ap 23.7

8. “No. 52," “Goldfinch " = Carpodacus purpureus ? “ May

I3th."

9. “No. 53," * Chip-bird" =? * May 13.”

10. “No. 56," “common Swallow” = Progne subis ? * April `

1I. “No. 66," “Grasshopper Gull” — Larus “canus” argen-

tatus. “May 16.”

12.“ No, 65, “Plover” =?“ May 16.”

13. “71,” “Scapog-Bird " — Hematopus palliatus or Rhyn-

chops nigra? If either of these is the bird mentioned it makes

the only record of occurrence in Rhode Island.

14. * No, 77, Gull” = ?: “May 24."

15. “79,” “Port Royal Bird” — Ampelis cedrorum ? “rare.”

* May 29."

16. “No. 83," * bee-bird " — Tyrannus tyrannus? “June 7.”

17. “84,” “dipdapper ” =? “June 7."

18. “No. ror," “yellow bird” = Dendroica estiva? “June

26."

19. “No. 104,” “black snipe” = Helodromas solitarius?

“Ful. A”

THE LITERATURE OF EDESTUS.

C. R. EASTMAN.

Ir has happened not infrequently that discoveries of the most

surprising nature in paleontology have been made almost simul-

taneously in different parts of the world. Hardly has some

form of animal life, previously unheard of and apparently unique,

been brought to light, when identical or closely related types

are reported from remote regions. Familiar coincidences of this

nature are recalled by Pareiasaurus amongst reptiles, Helicoprion

amongst fishes, and Daemonhelix amongst problematical fossils.

Although our knowledge of Helicoprion is comparatively

recent, a very considerable literature has suddenly sprung into

being concerning it and related forms, of which the older-known

Edestus and Campodus are the most instructive and important.

The latter, in fact, provides the only satisfactory clue we possess

regarding the anatomical and systematic position of the whole

series of Edestus-like forms.

Without entering into any general discussion, it may be said

that the majority of writers concur in the opinion that the

“spiral saw” of Helicoprion and the arched segments of Edes-

tus represent stages of that peculiar modification amongst Pale-

ozoic sharks whereby series of teeth become fused and inrolled

without being shed. The most recent communication that has

appeared on this subject strikes a slightly discordant note, in

that the author, Mr. Edwin T. Newton, suggests that Helico-

prion and Edestus may not be of the same general nature after

all. Although admitting that the former may be very plausibly

regarded “as the enrolled dentition at or near the symphysis of

an Elasmobranch, possibly allied to Cestracionts," his interpre-

tation of Edestus is that it is a segmented dermal defence, such

as a dorsal fin-spine.

1 Newton, E. T. On the Occurrence of Edestus in the Coal-Measures of

Britain. Quart. Journ. Geol. Soc., vol. 60, 1904, PP- 1-8, pl. 1.

405

406 THE AMERICAN NATURALIST. [Vor. XXXIX.

As has just been observed, a key to the understanding of

Edestus-like forms is furnished by the symphysial dentition of

Campodus, and there lies at hand a simple and reliable test for

demonstrating their common plan of structure. For those who

have not actual specimens at command, recourse must be had

to plaster casts of Campodus and Edestus, which fortunately

are not rare among the larger museums of this country. If

one will place side by side the symphysial segments of Campo-

dus variabilis and Edestus heinrichi, orienting them in natural

position with the anterior end foremost, one will be struck by

their almost perfect correspondence, part for part, and line for

line. >

First and most conspicuously, it will be noted that the:coronal

apices of Campodus and Edestus are similarly formed, their

edges being denticulated and sides. striated. in: corresponding

manner. It will be seen further that the basal portion of the

crown projects forward characteristically in both forms, and that

the different segments overlap and are fused with one another in

an identical fashion. Only in Edestus is the peculiar trough-like

base much produced forwardly, and being: composed of vaso-

dentine, is usually well preserved, whereas in Campodus the

basal support for the teeth is cartilaginous, and hence unsuited

for preservation. But the structural resemblance of all parts

IS SO Obvious, especially when one occupies himself with original

specimens, that the idea of a homology existing between them

cannot be avoided. In fact, the evidence appears conclusive

that Campodus, Edestus, and Helicoprion represent successive

stages of modification amongst Cestraciont sharks. The impor--

tance of these forms from a morphological standpoint is such,

and the discussion of them so widespread, that it seems desirable

ioa up an index to their special literature, which is given

elow.

No. 462] LITERATURE OF EDESTUS. 407

BIBLIOGRAPHY.

VAN DEN BROECK, E.

:03. Ce que doit signifier la spirale de Helicoprion. Bull. Soc. Belge

A ss vol. 13 (for 1899), Procès-verbaux, pp. 215-218.

DEAN

'95. r ishes, Living and Fossil. New York, 8vo, pp. e

DEAN, B.

98. Ona New Species of Edestus, Æ. Zecontei, from Nevada. Trans.

N. Y. Acad. Sci., vol. 16, pp. 61—69, pls. 4-5.

EASTMAN, C. R :

Karcionkys Genus Helicoprion. Amer. Naturalist, vol. 34, PP-

82.

EASTMAN, C. R. ;

:01. On Campodus, Edestus, Helicoprion, etc. Science, n. S., vol. 14,

795:

EASTMAN, C. R.

:02. On Campyloprion, a New Form of Edestus-like Dentition. Geol.

Mag., dec. 4, vol. 9, pp- 148-152, pl. 8.

EASTMAN, C.

:02. Some Carboniteions Cestraciont Acanthodian Sharks. Bull.

Mus. Comp. Zoöl., vol. 39, PP- 55-99 pl. 1-7.

EASTMAN, C. R. i :

:02. Genus Campodus de Koninck. Amer. Naturalist, vol. 36, PP-

852-854.

EASTMAN, C KR. 2

nn Fishes from the Central Western States. é

Mus. Comp. Zoöl., vol. 39, PP: 163-226, pl. 1-5.

Eesti C. ls so

The Nature of Edestus and Related Forms. Mark Anniversary

Volume, pp. 279-289, pl. 21.

Fucus, T. ;

00, Ueber die Natur der Edestiden, etc. Sitzungsber. Akad. Wiss.

Wien, vol. 109, pp- 5-9, pl.

HITCHCOCK, E. : :

'56. Account of the Discovery of the Fossil Jaw of an Extinct F vod

of Sharks from the Coal Formation. roc. Amer. Assoc. .

Sct. for 1855, pp. 229-230.

Hitcucock, FANNY R. M. ge

On the Homologies of Edestus. roc. Amer. Assoc. Ard

1887, p. 260. Also Amer. Naturalist, vol. 21, 1887, PP- 847-84

JAEKEL, O. :

'99. Ueber die Organisation der Petalodonten. Zeitschr. deutsch. geol.

Gesellsch., vol. 51, p. 297-

408 THE AMERICAN NATURALIST. [Vor. XXXIX.

JAEKEL, O.

A. Karpinsky: Ueber die Reste von Edestiden, etc. [Review].

Neues Jahrb. f. Mineral., vol. 2, 1900, pp. 144-148.

JORDAN, D. S.

: A Guide to the Study of Fishes. Vol. 1, p. 529.

KARPINSKY, A. P.

" Ueber die Reste von Edestiden und die neue Gattung Helico-

prion. Verh. russ.-kais. min. Gesellsch. St. Petersb., ser. 2, vol. 36,

PP. 361-476, pls. 1-4. Also, Mém. Acad. Imp. Sci. St. Petersb.,

ser. 8, vol. 8, pp. 1-76, pls. 1-4.

KARPINSKY, A. P.

Ueber neue Literatur und andere Daten betreffend Reste von

Helicoprion. Verh. russ.-kais. min. Gesellsch. St. Petersb., ser.

2, vol. 40 (Protocolle der Sitzungen), p. 94.

KLaarscH, H. ;

:01. Zur Deutung von Helicoprion Karp. Centralbl. f. Mineral. (1901),

PP- 429-430.

Koken, E.

:01. Helicoprion im Productus-Kalk der Salt-Range. Centralbl. f.

Mineral. (1901), pp. 225-227.

LEIpy, J.

'56. Indications of Five Species, with two New Genera of Extinct

Fishes. Proc. Acad. Nat. Sci. Phila., vol. 7, 1854—55, p. 414.

LEıpy, J.

'57. Remarks on certain Extinct Species of Fishes. Proc. Acad. Nat.

Sci. Phila., vol. 8, 1856, p. 301.

Lery, J.

'58. Descriptions of some Remains of Fishes, etc. Journ. Acad. Nat.

Sci. Phila., ser. 2, vol. 3, 1856, pp. 159-165, pl. 15.

LouEst, M.

'83. Recherches sur les poissons des terrains paléozoiques de Belgique.

Ann. Soc. Geol. Belg., vol. 11, pp. 295-328.

NEWBERRY, J. S.

: In Geol. Surv. Zllinois, vol. 2, Paleontology, p. 84, pl. 4.

NEWBERRY, J. S,

89. On the Structure and Relations of Edestus, etc. Ann. N. Y.

Acad. Sci., vol. 4, 1888, pp. 113-122, pls. 4-6. Also Monogr.

U. S. Geol. Surv., vol. 16, 1889, pp. 217-226, pls. 39-40.

NEWBERRY, J. S., AND WORTHEN, A. H.

" In Geol. Surv. Illinois, vol. 4, P- 350, pl. 1, fig. 2.

NEWTON, E. T.

:04. On the Occurrence of Edestus in the Coal Measures of Britain.

Quart. Journ. Geol. Soc., vol. 6o, pp. 1-8, pl. ı. [Followed by

discussion by A. s. Woodward.] Also Geo/. Mag., dec. 5, vol. 1,

P. 40.

No. 462.] LITERATURE OF EDESTUS. 409

OWEN, R.

'61. Palaontology. 2d ed., Edinburgh, 8vo, pp. 123-124, fig. 38.

ST. JOHN, O. H.,

:02. [Observations on Edestus and Cochliodus.] Amer. Naturalist,

vol. 36, pp. 658-39.

St. JouneO. H., AND WORTHEN, A. H

75. In Geol. Surv. Illinois, vol. 6, pp. 318-323, pl. 8.

SIMOENS, G.

:03. Note sur Helicoprion bessonowi Karpinsky. Bull. Soc. Beige

Géol., vol. 13, 1899, pp. 235-244-

TRAUTSCHOLD, H.

"79. Die Kalkbrüche von Mjatschkowa. Nouv. Mém. Soc. Imp. Nat.

Moscou, vol. 14, p. 49, pl. 6, fig.

buon igiene oe

Ueber Edestus und einige andere Fischreste des moskauer Berg-

kalke. Bull. Soc. Imp. Nat. Moscou, vol. 58, pt. 2, 1883, pp-

160—174, pl. 5.

TRAUTSCHOLD, H.

'86. Ueber das Genus Edestus. Bull. Soc. Imp. Nat. Moscou, vol. 61,

pt. 2, 1885, p. 94.

Ae H.

Ueber Edestus protopirata Trd. Zeitschr. deutsch. geol. Gesellsch.,

vol. 40, p. 750.

TRAUTSCHOLD, H

'90. Ueber Protopirata centrodon Trd. Bull. Soc. Imp. Nat. Moscou,

no. 3, PP- 317-321.

VAN DE WIELE, C.

:08. Aperçu sur les vestiges fossiles d’Edestides, etc. Bull. Soc. Belge

Géol., vol. 13, 1899, pp. 205-218, 231-234, 244-247:

WOODWARD, A.

'91. Catalogue ot the Fossil Fishes in the British Museum, pt. 2, pp.

151—154

WOODWARD, A. S

:00. Helicoprion — Spine or Tooth? Geol. Mag., dec. 4, vol. 7, pP-

33-36.

hiec A. S.

Note sur l'Helicoprion et les Edestides. Bull. Soc. Belge Géol.,

vol. 13, 1899, Procès-verbaux, pp. 230-233.

WOODWARD, H.

On a Remarkable Ichthyodorulite from the Carboniferous Series,

etc. Geol. Mag., dec. 3, vol. 3, pp- 1-7, Pl. 1-

YABE, H.

:03. On a Fusulina-Limestone with Helicoprion in Japan. Journ. Geol.

Soc. Tokyo, vol. 10, pp. 1-13, pl. 1-2-

ZITTEL K. A.

:02. Textbook of Paleontology. un ed., vol. 2, p. 27.

NOTES. AND LITERATURE.

ZOOLOGY.

Guide to the Birds of New England and New York.'— This

guide to the birds is on the same general plan as a number of recent

bird-books, but the effort has been made to adapt it especially to the

most elementary beginners. For this purpose it appears to be well

fitted, and the author is to be complimented upon his constant appre-

ciation of the limited view-point of the novice in bird study., Brief

introductory chapters deal with “ The object and plan of this guide,”

“ Birds and their seasons,” “ Migration,” “ Distribution,” “ Hints for

field work,” and “How to use the keys.” The result of intimate

experience with beginning field classes is apparent in these hints.

The. keys include only “the common Jand-birds of New England

and eastern New York,” omitting “the hawks, the owls, the Mourning

Dove, and the game-birds.” Separate keys are given respectively

for winter, for.March, for April, for May, for summer, and for autumn,

and each of these has under separate divisions those birds which one

may expect to find only in the. Upper Austral or the Canadian life-

zones, These keys are based primarily upon conspicuous coloration

and secondarily upon size, supplemented by characteristics of color,

habits or habitat. Taken in connection with the fuller descriptions,

and often excellent, brief biographies given in the body of the work,

they impress one as being very efficient, In the descriptive portion

are incorporated the water birds and others not included in the scope

of the keys, and one cannot but regret that some guide is not given

to aid in their identification as well. The illustrations consist of five

full-page plates, including a map showing the life-zones in New

England, and ninety-five text figures, which add much to the useful-

ness of the book. L.

Hornaday's American Natural History.?— It is perhaps unfor-

1 Hoffmann, Ralph. A Guide to the Birds of New England and New York.

Boston and New York, Houghton, Mifflin & Co.

- 2 Hornaday, William T. 74e American: Natural History. A foundation of cmi

ful knowledge of the higher animals of North America. fe

drawings by Beard, Rungius, Sawyer, and others, 116 photographs, chiefly by

Sanborn, Keller, and Underwood, and numerous charts and maps. Charles

Scribner’s Sons, New York, 1904. Large Svo, xxv + 449 pP-

41I

412 THE AMERICAN NATURALIST. (Nou. XXXIX.

tunate that a work dealing with the vertebrates only should pre-empt

such a broad title as “The American Natural History," which, with-

out the accompanying subtitle, is apt to be rather misleading. ‘The

latter, “A foundation of useful knowledge of the higher animals of

North America," is much more nearly descriptive of the character of

the book in hand. As the author states in his preface, it has been

his primary intention to provide for the boys and girls of North

America between the ages of fourteen or fifteen and the age at which

they usually enter the university, an introduction to the * higher ani-

mals” of the continent, in a form that will be interesting and pleasing

as well as instructive ; also to furnish a book of reference for teach-

ers in the intermediate grades. All who have read Mr. Hornaday's

“Two Years in the Jungle” are aware of his ability to write

entertainingly, and his years of experience in the field and in the

New York Zoölogical Park have given him opportunities for study-

ing the living animals such as comparatively few men have had.

These advantages have been combined to make * The American

Natural History" good and instructive reading, not only for young

people, but for any who have a limited acquaintance with our ani-

mals.

In general, only the commoner forms have been selected for treat-

ment, but in some cases descriptions are given of the rarer species,

while a number of exotic animals, such as the Monotremes, the fruit-

eating bats, etc., are introduced to fill the gaps in the North Ameri-

can fauna. The treatment of the various forms varies considerably,

apparently to a large extent with the author's interest. The portion

dealing with the Ungulates is especially extensive and contains much

original information gained from experience with the animals in cap-

tivity. Throughout the work a special point has been made of refut-

ing popular fallacies, such as, that beavers use their tails as trowels,

that porcupines shoot their quills, that mountain sheep alight on their

horns, and that the hog-nosed snake is poisonous, — a feature which

should be conducive of good results. Protection, especially of the

game animals, has also received considerable attention and emphasis,

a subject which it is well to bring to the attention of the public

whenever possible.

The illustrations are numerous, and in most cases excellent. This

is especially true of the reproductions of photographs, which cannot

be praised too highly; but on the other hand, some of the drawings,

especially of the mammals and fishes, seem hardly up to the standard

of the day, at least in artistic effect. One cannot but wish that in

No.462] ., OTËS AND LITERATURE. 413

some cases the backgrounds had been omitted entirely, as in the

figure of the sawfish (p. 435), the chimera (p. 431), and others. It

is a question, too, whether the painting-in of other backgrounds in

photographs is legitimate in a book of this nature, and whether it is

not apt to be misleading to beginners when no explanation is given.

One might imagine, for example, that the puma (p. 20) is a docile

beast which poses calmly in its mountain home in order to be photo-

graphed ; see also the polar bear (p. 36), the flamingo (p. 266), etc.

'The *landscape charts" used to illustrate relationships and habitat

seem rather strained and overdrawn, while these and the text are

somewhat misleading in constantly referring to animals as “higher”

and *lower," tending to give the student an idea that the vertebrate

affinities lie in a direct chain, rather than forming a complicated,

branching system.

Mistakes of fact are by no means lacking, especially points in the

anatomy of the exotic species; and the classification is throughout

largely artificial and based upon superficial resemblances and analo-

gies.

In the introduction the author makes some very conservative

remarks regarding the tendency to humanize animals and to ascribe

to them a higher order of intelligence than they possess ; but unfor-

tunately he has in many cases been unable to avoid at least the

semblance of the fault himself, as when he says (p. 93): “ Zhe most

humorous of all rat-like animals is the Trading Rat, .... which

delights in playing practical jokes upon its human neighbors" He

-is perhaps inclined at times, too, to make over-positive statements

which cannot be taken quite literally.

This book will probably not become generally used as an interme-

diate text-book ; but it will be found a partial substitute for those

who have no opportunity to visit a good zoölogical park, and. will

certainly add greatly to the pleasure of those who do have that

privilege. It is an excellent work for home reading and reference.

L. J. C.

Notes. — The zoógeographical relations of South America recently

. have been discussed by Dr. G. Pfeffer (Zoöl. Jahrb., Suppl. 8, 1905,

PP. 407-442), with reference to the reptiles, amphibians, and fishes,

especially as to the question of the former land connections of this

continent with Africa and with Australia. It is apparently the desire

of the author to demonstrate that there is no evidence whatever for

the assumption of such connections, and, consequently, the paper

414 THE AMERICAN NATURALIST. | [Vor. XXXIX.

chiefly discusses those cases, which are not in favor of the former

land connection between these continents, that is to say, which .do

not directly bear upon this question, while other cases, which might

possibly furnish additional evidence are dismissed shortly.

The general trend of Pfeffer's argumentation is as follows. There

are a number of instances, where discontinuous distribution in all or

some of the southern. continents is evidently a remnant of a former

universal or subuniversal distribution, which is clearly shown by the

presence of fossil remains of the several groups of animals in other

parts of the world. On the other hand, there are similar cases, in

which fossil remains are not known at all, or are not known from the

northern continents. Here, Pfeffer claims, we have the right to

assume, that these groups nevertheless once existed on the northern

hemisphere, and they also once were subuniversal in their distribu-

tion.

Here we are again confronted with a fallacious generalization of

correct observations, a way of drawing conclusions that has so often

given origin to incorrect general theories. Of course, if some groups

of animals, that are now more or less restricted, were once universal

in their distribution, it is evident, that very likely some others were,

of which no direct evidence of universality has been found. But the

conciusion, that all such cases are to be explained by this assump-

tion, is, to say the least, a little rash. Moreover, we do not intend to

find a theory that might under certain assumptions explain the

present facts, but we ought to try to find the correct explanation, and

thus no way of ascertaining the latter should be neglected, and

doubtful cases should not be dismissed shortly, but subjected to a

careful and thorough study.

In the present paper, Pfeffer only talks of paleontological evidence,

and almost entirely neglects the morphological (systematic) relations

of the different forms. It is sufficient. for him, if certain forms are

found in Africa and South America, to point out that they might

have been once present also in North America and Eurasia, and that

thus a connection may be established (over Bering Sea). If similar

forms are also found in India, this assumption seems to him beyond

question. He does not pay the slightest attention to the mutual

relations of these forms.

Now it is a fact, that the former land connections between tropical

South America and Africa, and between southern South Africa and

Australia have been supported chiefly by studies of the degree of the

relation of their faunas. We: know cases where members of the

No. 462] NOTES AND LITERATURE. 415

fauna of South America find allied forms in many parts of the world,

but where the most closely allied forms are found in Australia ; in

other cases, the nearest relations are found in West Africa. For

such cases the theory of former subuniversal distribution is entirely

insufficient, and only leads to the further question, why it is, that

from a former universal distribution, the most closely allied remnants

are found in the most remote parts? For we must always bear in

mind, that, if we do not admit direct connections between South

America and Africa, and South America and Australia, the connec-

tion of these parts always goes by way of Bering Sea or Greenland.

- Pfeffer himself mentions’a number of instances, where the present

distribution appears to favor a direct connection of the three southern

continents, but he never studies them closely, and is satisfied with the

conclusion that they very likely are also remnants of a former sub-

universal ‘distribution. The following are the most striking examples:

Chelonia, family Miolaniide ; Lacertilia, genus Mabuia, family

Amphisbenide; Ophidia, families Typhlopide and Glauconiidz,

genus Leptodira; Batrachia Anura, families Pipidze, Cystignathidze,

Hylidz, and Engystomide; Batrachia Apoda, family Coeciliidz ;

Teleostei, families Characinid&, Symbranchidze, Serranid&, Cichlidz.

I do not say that these groups actually furnish evidence for the

supposed former connections of the ‘southern continents; I only

want to call attention to them, with a view to having them made the

object of careful, detailed, and unprejudiced examination, paying

principal attention to the mutual affinities of their representative

members in the different parts of the world. Pfeffer has not done

this, and thus his treatment of these groups is superficial and unsat-

isfactory ; in some of the above instances, objections to the assump-

tion of former subuniversality of distribution are evident at the first

gu —9

Thus Pfeffer's final conclusion, that there is no necessity for the

assumption of direct land connections between South America and

Africa, and South America and Australia, upon zoögeographical

grounds, is not properly supported even with reference to those

groups which he made his special object of study in the present

paper. In the face of the fact that there are other groups not men-

tioned and studied by Pfeffer, that have furnished positive evidence

for these connections, and in which the assumption of former subuni-

versal distribution is entirely unsatisfactory, rendering the present

conditions only more unintelligible, we get the impression that

Pfeffer did not take up these studies with an unbiased mind.

416 THE AMERICAN NATURALIST. (VoL: XXXIX.

One additional objection should be made. Pfeffer repeatedly talks

of a pre-Tertiary South America, and of the separation of South

America from the rest of the world at the end of the Cretaceous

time (p. 411, p. 427, p. 430; “prapanamensisches Pan-America ").

This tends to show that his ideas about the geological history of

South America are entirely at variance with certain geological facts.

We know that there was no South America at all as a continuous

mass before the beginning of the Tertiary, and that the first connec-

tion of what is now South America with North America falls into the

Miocene. For this we do not possess a mere theory, but positive

geological facts; it is impossible to deny the existence of Jurassic and

Cretaceous marine deposits over large parts of South America, or to

neglect the fact of their existence. But if we pay due attention to

this, then it is inadmissible to speak of a pre-Tertiary South America,

and to talk of a severing-off of South America from the rest of the

world at the end of the Cretaceous.

A. E. ORTMANN.

A detailed account of the anatomy of the chiton, Cryptoplax larve-

formis, has been published by E. Wettstein (Jena. Zeitschr., Bd. 38,

P- 473).

N. Maclaren (Jena. Zeitschr., Bd. 38, p. 573) discusses the struc-

ture and systematic relations of two trematodes, Diplectanum equans

Wagener and Nemathobothrium mole n. sp.

Anatomy and Histology of Dentalium. — The following facts are

recorded by M. Boissevain (Jena. Zeitschr., Bd. 38, p. 553) on the

anatomy and histology of Dentalium. The whole foot is ciliated and

glandular. The intestinal musculature consists of a thin layer of cir-

cular fibers with occasional muscle bridges. The subradular organ

carries an organ of taste. The communication between the genital

glands and the kidney is renewed with each period of sexual activity.

F. A. Bather, in the Geological Magazine (dec. 5, vol. 2, p. 161)

characterizes Sympterura minveri,n. g. et sp., a Devonian Ophi-

urid from Cornwall. The genus is thus diagnosed: a Lapworth-

urid with spinulose disc extending to second arm-segment, with

oral skeleton of teeth, long jaws, and short mouth-frames (torus

not seen), with free arm-segments containing a vertebral ossicle,

possibly compound, grooved ventrally and provided on each side

with two wings, to the distal of which is attached an adambulacral

spiniferous element, The structure of the arm-segments suggests

No. 462.] NOTES AND LITERATURE. 417

that the vertebrae may be composed of two successive pairs of

ambulacral elements, and reasons are given for suspecting that this

may be the case in all the more advanced Ophiurids. ‘The holotype

of the species, which is the first echinoderm described from these

Cornish slates, is in the British Museum.

In recent numbers of the Bulletin du Musée Océanographigue de

Monaco, E. Chevreux describes two new deep-sea amphipods, Cypho-

caris alicei and C. richardi, from the waters between the Canaries

and the Azores. G. O. Sars contributes the first part of a prelim-

inary list of the Calanoids collected during the Prince of Monaco's

deep-sea explorations. A list of the Symphyla and Diplopoda of the

principality of Monaco is given by H. W. Brölemann.

The migratory movements of certain species of Pierids in the

Amazon valley are described by Dr. Geeldi in vol. 4 of Boletim do

Museu Geldi. The same journal contains a list of the Brasilian

birds described by Spix, Wied, Burmeister, and Pelzeln, and a cata-

logue of the mammals in the collection of the Para Museum. A

number of interesting notes on the mammals are added and well

executed plates illustrate several of the species.

(No. 4617 was issued May 6, 1905).

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THE

AMERICAN NATURALIST.

Vor. XXXIX. July, 1905. No. 463.

RESTORATION OF THE TITANOTHERE

MEGACEROPS.

RICHARD S. LULL.

IN A recent study of a fine specimen of Megacerops discov-

ered in the Bad Lands of South Dakota by an expedition from

Amherst College, the author was impressed by several features

which suggested a somewhat radical departure from the gener-

ally accepted restorations of these remarkable animals. The

accompanying photograph from a model by the author aims to

express his conception of the creature in the flesh.

The Amherst specimen was found in the Titanothere (White

River) Beds about thirty-five feet above their base, in a place

where practically all of the one hundred and eighty feet of the

deposits were exposed. Hence it is reasonable to suppose

that the remains represent a species not very primitive, nor yet

showing the extreme of specialization exhibited by later forms,

in other words a fairly typical titanothere.

The creature was of adult stature, though the vertebral

epiphyses had not coössified with their centra ; but, as Marsh

has shown, this feature, which one also finds in the elephants,

implies the late maturity which is correlated with huge size.

419

[Vor. XXXIX.

THE AMERICAN NATURALIST.

‚ıoyyne sy} Aq [opour e woaz *sdoraoeSo Py 9191jouejr a Jo uonvio1sasp —ı *514

No. 463.] RESTORATION OF MEGACEROPS. 421

The full dentition had been acquired, the teeth being somewhat

worn, which would seem to indicate an animal in its prime.

The titanothere measured about seven feet four inches in height

to the withers and a little more than twelve feet in length. Its

weight was probably between one and a half and two tons.

The general proportions suggest the rhinoceros, though,

while remarkably specialized as to dentition and the armament

of the head; in other respects the titanothere is more primitive

than any other perissodactyl, notably in the shorter back and in

the structure of the fore foot.

The limbs are stouter than in the rhinoceros, especially at the

wrist and ankle, and the degree of angulation between the various

segments is less, probably to withstand the greater bodily weight.

The fore limb is remarkably robust, and the great roughenings

on the various bones, notably the humerus and the olecranon

process at the elbow imply enormous muscular power. The

fore foot is four-toed and symmetrical, with the main axis lying

between the third and fourth digits as in artiodactyls. The

retention of the outer digit would seem to imply that the great

weight of the head and shoulders necessitated strength rather

than a modification for speed. In the extremely flexible though

strong wrist and the immense olecranon process one sees indica-

tions of a supple limb, a compromise between the pillar-like sup-

porting limb of the elephant and one which would give its owner

more agility in lying down or rising, or in charging its enemy.

The hind limb departs from the rhinoceros type mainly in the

straightness of the upper segment whose bone, the femur, is

long, without a conspicuous third trochanter, and with its shaft

flattened fore and aft in such a manner as to imply that the

strain brought to bear upon it during life was in the direction ef

its length. While the calcaneum is rather prominent, the limb

must have been but little flexed at the ankle and almost straight

when viewed from the rear; decidedly more elephantine than

rhinoceros-like in general aspect.

'The most notable feature of the trunk, aside from its relative

shortness, is the great height of shoulder resulting from the

elongated spines of the anterior dorsal vertebra, which have

well roughened extremities for the attachment of the liga-

422 THE AMERICAN NATURALIST. [Voı. XXXIX.

mentum nucha and the huge muscles which supported the

skull. Neither the rhinoceroses nor the elephants exhibit such

a development as this and one is reminded irresistibly of the

bisons in which the head becomes an offensive weapon of great

power. Certainly this development implies more than the mere

passive support of the head and is probably directly correlated

with the development of the cranial armature.

Fic

Museum.

2.— Anterior

view of the skull of Megacerops, from a specimen in the Amherst College

Rhinoceroses charge their enemies, using the nasal horn with

good eitect, and here again there seems to be a direct relation-

= D At ureon » ge ý

ship between the height and power of the shoulders and the

>oree of devel. ee i

degree of development of the horns. In the rhinoceros, how-

No. 463.) RESTORATION OF MEGACEROPS. 423

ever, the thrust is a vertical one, whi'e in most titanotheres,

notably in the one under consideration, there is evidence of

strong lateral as well as vertical motion.

In the genus Symborodon the horn prominences are not con-

nected by a web or bridge of bone as in this genus, Megacerops,

which would indicate in the former an absence of lateral stress

against the horns as though they were used more as in Rhino-

ceros. It would be interesting to note whether a comparative

study of the skeletons would indicate the development or

strengthening of special muscles in forms wherein the lateral

stress obtained.

The titanothere skull is one of the most unique and bizarre

Fic. 3.— Head of the Megacerops restoration showing the nasal horns.

among mammals, due to the development of the remarkable

nasal prominences which bore the horns and the wide expanse

of the zygomatic arch which, in the later types, became a broad

shelf-like expansion of bone. The development of the zygo-

mata and the height and breadth of the occiput seem to be

directly correlated with the development of the horns, the neces-

sity being to provide leverage for the effective use of these

weapons. i

In the previous titanothere restorations the nasal prominences

are always indicated as sheathed with horn, but a glance at the

photograph of the skull will disclose the total absence of vascu-

lar impressions such as the horn cores of cattle and of the great

424 THE AMERICAN NATURALIST. (Vor. XXXIX.

horned dinosaurs (Ceratopsia) always exhibit. Another feature

which is indicated in the figure is that the summit of each main

prominence as well as those of the lesser secondary ones are

curiously rugose resembling, though the ruga are coarser, the

roughened patches beneath the horns of the rhinoceros.

Thus one is led to doubt the probability of a horny sheath

covering the entire prominence, yet the very mobility of the

neck and the strength of the head-wielding muscles indicate

the presence of an efficient armament of a size commensurate

with the strength of its support. This together with the rugos-

ities seems to point to the existence of horns formed, as in the

rhinoceros, of agglutinated hair-like fibers; a larger pair upon

the summits of the main, and, in this species, a lesser pair upon

the secondary prominences.

This conception perhaps renders the creature somewhat more

grotesque, but it would surely provide him with offensive and

defensive weapons which with his evident prowess would make

the titanothere peerless among the creatures of his time.

AMHERST, Mass.

SYNOPSES OF NORTH AMERICAN

INVERTEBRATES.

XXI. THE NEMERTEANS.

WESLEY R. COE.

PART I.

SPECIES ÜCCURRING ON THE WEST AND NORTHWEST COASTS OF

NORTH AMERICA.!

Tue Nemerteans embrace a highly specialized group of flat-

worms, the most characteristic features of which are the soft

extensible body without indication of external segmentation, the

highly developed eversible proboscis, the straight intestine, open-

ing at the posterior end of the body, and the absence of any

distinct body cavity.

. The body is commonly long, flattened, and ribbon-like

(Cerebratulus), filiform (Cephalothrix, Lineus), broad and flat

(Drepanophorus), thick and rounded (Euborlasia), or short and

cylindrical (Tetrastemma), but in nearly all forms is extremely

extensible and may often be contracted to one tenth the length

of the fully extended worm. In size there is the greatest varia-

tion found in any group of worms, for there are minute species

(Tetrastemma) but 5 mm. long and a half millimeter thick when

sexually mature, while another (Zineus longissimus) may become

1Of the 87 species which have thus far been recorded from the west and

northwest coasts, only 19 are known to occur on the east coast of North Amer-

ica or in other regions of the globe. Because of this geographical limitation of

extent on anatomical

peculiarities, which liave been somewhat more fully studied in the Pacific species

than in those from the east coast of North America.

425

426 THE AMERICAN NATURALIST. (Vor: XXXIX.

25 meters in length when fully extended, but remains as slender

as a thread; still another (Cerebratulus lacteus) grows to be 7

meters long and 20 mm. wide, while the single known individual

of Euborlasia maxima was 45 mm. in width after preservation.

Although the body is without external segmentation, many of

the internal organs are metamerical arranged. The body is

covered throughout with glandular and ciliated epithelium. A

true body cavity being wanting, the space between the muscular

walls of the body and the intestine is filled with gelatinous

tissue, or parenchyma. Many species of the Heteronemertea

have a delicate caudal cirrus beneath the anal opening at the

posterior end of the body, and the representatives of a single

genus (Nectonemertes) are provided with a pair of lateral swim-

ming appendages near the anterior end of the body.

The proboscis is bathed in a corpusculated fluid, enclosed in a

Special muscular sheath, and opens at the anterior end of the

body, sometimes in connection with the mouth and sometimes

separately. In many species it is nearly as long as the body

itself; it is lined with glandular epithelium, and in certain genera

is provided with rhabdites or nematocysts. In one of the four

orders (Hoplonemertea) there are highly specialized calcareous

stylets of such definite size and shape that they form most con-

venient and reliable diagnostic features.

The mouth is situated anteriorly, either in front of the brain,

as in the Hoplonemertea, or immediately behind it, as in the

other two orders. The mouth leads into the esophagus, which

is often demarcated from the succeeding portion, the stomach ;

the latter opens into the intestine, which in most genera is pro-

vided with paired lateral diverticula. In the Hoplonemertea the

stomach is prolonged into a narrow tube, pylorus, which opens

well back of the anterior end of the intestine, the latter thus

extending forward beneath the pylorus as the intestinal caecum.

Other appendages occur in certain species.

The blood circulates in two or three longitudinal vessels, which

usually have numerous anastomoses and open into one or more

large lacunz in the head.

The excretory organs, or nephridia, usually consist of a pair

of lateral canals, the ramifications of which lie in close relation

No. 463] WORTH AMERICAN INVERTEBRATES. 427

with the blood vessels in the esophageal region. One or more

efferent ducts lead from each main canal to the exterior of the

body or, in rare instances, to the esophagus.

The muscular system consists of either two or three strong

layers of fibers, the arrangement of which forms a convenient

diagnostic character and is described in the key to the orders.

In some forms there are additional secondary layers.

The relative position of the principal nerve cords with respect

to the muscular layers is likewise of primal importance in clas-

sification. The central nervous system consists of a four-lobed

brain, the two lobes of each side being closely united with each

other and joined to those of the other side by a commissure

above and one below the rhynchodzeum, and a pair of large lat-

eral nerves, accompanied by ganglion cells, extending from the

ventral pair of brain lobes to the posterior end of the body. In

addition, a dorso-median nerve is commonly present, and some-

times a ventro-median one ; most forms have a pair of well devel-

oped esophageal nerves, and nearly all have special proboscis

nerves, together with peripheral nerves to the integument,

ocelli and other sense organs. In most forms a pair of highly

specialized cerebral sense organs lie in close proximity to the

dorsal brain lobes, with which they are completely fused in the

Heteronemertea. A pair of lateral sense organs occur on the

lateral margins of the body in the nephridial region in many

Paleonemertea ; frontal sensory pits are found on the tip of the

snout in many forms, while Carinoma has a number of sensory

pits on the dorsal aspect of the head. Ocelli are often present

in considerable numbers, but are wanting in the Paleonemertea

and in many species of the Heteronemertea.

The sexes are separate in most species, although a few are

hermaphroditic. The sexual products develop in simple sacs

in the body parenchyma and are discharged directly upon the

surface of the body. Where lateral intestinal lobes are devel-

oped the gonads often alternate with them with much regu-

larity.

In the larval development, some forms (Lineidz) pass through

a complicated metamorphosis, with the formation of a free-swim-

ming larva of highly specialized form (pilidium, or Desor's larva),

428 THE AMERICAN NATURALIST. (Vor. XXXIX.

but in other forms (Amphiporus, Cephalothrix) development

is direct, or is accompanied only by a shedding of the larval

integument.

Nearly all species are marine, living under stones, among

alga, or in burrows in the sea bottom or shore between tides ;

representatives of a single widely distributed genus (Sticho-

stemma) live in fresh-water pools, ponds, or rivers, and several

Species live in moist earth in warm climates ; a few forms are

commensal, inhabiting the mantle chambers of pelecypods or of

ascidians, while the members of a single genus (Carcinonemer-

tes) are truly parasitic, living among the gill plates or egg masses

of various species of crabs.

All Nemerteans may be conveniently arranged in four orders,

comprising more than thirty genera and several hundred spe-

cies. Of these, 21 genera with 87 species have been recorded

from the Pacific coast, the Nemertean fauna of that region

being more abundant and more diversified than in almost any

other locality of equal extent.

For convenience in determination, the 87 species at present

known from the west and northwest coasts of North America,

from Panama to the Bering Sea and Arctic Ocean, may be

arranged in the following analytical keys, based mainly on super-

ficial and easily distinguishable characters.

The first key embraces the orders ; under each order is given

akey to those genera known to occur in the region designated,

and under each genus the species there represented.

The geographical distribution, so far as it is known at present,

of each of these species is indicated in the keys to species by

the following abbreviations : —

Arctic Ocean north of Bering Strait.

Bering Strait, Bering Sea, Aleutian Islands, Commander Islands.

Pacific coast of Alaska.

Puget Sound and British Columbia.

Central and northern California ; Monterey Bay.

Southern California; San Pedro and San Diego.

Gulf of California and southward to equatorial regions.

Eastern coast of North America.

European waters.

A prime mark (/) indicates that the species occurs in deep water off the

corresponding coast; the figures following indicate depth in fathoms.

KMMN OTP RZ

No. 463] NORTH AMERICAN INVERTEBRATES. 429

"er

Lad

Key.

Without sucking disk ; intestine not convoluted.

2. Proboscis o stylets; mouth posterior to brain; intestinal

caecu

3. Muscubi uei of body in two layers — outer circular and inner

longitudinal — to which ‘a third — inner circular — is sometimes

added; lateral nerves either eco muscular layers or imbedded

in longitudinal muscles ; cutis absen Paleonemertea.

31. Muscular walls of body in three main levers: of which the inner

is longitudinal; lateral nerves outside circular muscular layer ;

cutis well developed . . Heteronemertea.

2', Proboscis usually provided with idus 3h nont in front of brain,

usually opening with proboscis in a single terminal or subterminal

pore; intestinal caecum usually present; lateral nerves internal to

muscular layers of body walls . Hoplonemertea.

. With sucking disk at posterior end of bei i intestine convoluted

Bdell

ellonemertea.

Order Paleonemertea.

Paired intestinal diverticula emen ; a ; : : LO

Paired intestinal diverticula presen

Lateral nerves situated m diee Dr a ada of Mods

s CARINELLA.

Lateral nerves pue outside maci iavers in ER region,

but imbedded in longitudinal muscles behind nephridial region ; intes-

tine lobed, i without regularly paired diverticula ; cerebral sense

organs wanting CARINOMELLA.

Internal nr RE Re EEE in nephridial region ;

mouth situated immediately behind brain; body not very slender ;

head broader than neck ; nephridia well developed . CARINOMA.

Internal circular muscles but little developed in any portion of body;

mouth situated far behind brain; body filiform ; head sharply pointed

CEPHALOTHRIX.

CARINELLA.

Body of somewhat homogeneous color, without definite markings . 2.

With distinct longitudinal or transverse markings, or both 3.

Body very soft, attaining a length of upwards of 2 meters TER fully

extended ; deep red, orange, or bright vermilion

C. rubra etn B, A.

Body minute, very slender ; whitish and somewhat transluc

C. pellucida ve 65 X.

430 THE AMERICAN NATURALIST. (Vor. XXXIX.

u»

Yellow, rosy, or greenish, with black longitudinal and transverse mark-

ings. Body large, rather firm, only moderately slender, attaining a

length of 5o cm. or more; pale yellowish or rosy, sometimes with

greenish tinge, with 3 longitudinal velvety black lines and a series of

narrow rings of similar color ; ; : co C, renata Coe, S.

Red or brown, with white markings i ; ; > : MEE. M

Deep red, with a series of narrow white rings, but without longitudinal

lines. Body firm, rather stout, upwards of 30 cm. long ; deep red, with

a series of narrow white rings placed at frequent intervals throughout

body . 3 7 ; ; : i : . C. albocincta Coe, S.

Brown, with longitudinal and transverse white markings 5

. With 3 longitudinal white lines. Slender, up to a meter in length;

brown, with numerous narrow transverse rings and 3 parallel longitu-

dinal white lines, of which one is in the dorso-median line and one just

below each lateral margin : ; C. capistrata Coe, A, C.

ith 4, 5, or 6 longitudinal white lines . à 3 : eum rd

Body slender, subcylindrical, 15 cm. or more in length ; deep brown,

with a series of white rings and 4 longitudinal white lines, of which 2

are lateral, while the other 2 divide dorsal surface of body into three

equal parts . ; ; E 1 ; C. cingulata Coe, C.

Body slender, subcylindrical, often half a meter or more in length when

fully extended ; brown or chocolate, with numerous narrow transverse

rings and 5 or 6 parallel longitudinal white lines, of which one is in the

median dorsal line, two on each lateral surface, and the sixth, when

present, is usually merely indicated in the ventro-median line

. C. sexlineata Griffin, A, P, C, S.

CARINOMELLA:;

Body slender, usually 5 to 10 cm. in length; milk-white and somewhat

translucent, sometimes with yellowish or brownish intestinal canal

C. lactea Coe, S.

CARINOMA.

Body rather stout, flattened posteriorly ; milk-white with grayish or brown-

ish mottlings and darker intestinal lobes

C. mutabilis Griffin, P, C, S.

CEPHALOTHRIX.

Slender, filiform ; pale yellow, sometimes with reddish, grayish, or green-

ish tinge; no ocelli in adult

C. linearis (Rathke) Oersted, B, A, P, C, S, X, Y.

No. 463] NORTH AMERICAN INVERTEBRATES. 431

O N

[^]

DNE

Deep red, mahogany, or red

Order Heteronemertea,

Proboscis musculature of two layers, of which the outer is circular ;

muscular crosses absent in proboscis; cephalic glands usually ver

voluminous, extending posteriorly behind the brain; cephalic furrows

absent : ; . T&NIOSOMA.

. Proboscis musculature of two or three layers, of which the outer is

longitudinal; muscular crosses present in proboscis ; cephalic glands

usually but little developed, and not extending posterior to brain . 2.

. Without horizontal cephalic furrows on sides of head; caudal cirrus

present à : S ; ; ; ; ^ . ZYGEUPOLIA.

With conspicuous horizontal cephalic furrows on sides of head

Caudal cirrus absent ; proboscis sheath usually considerably shorter than

Caudal cirrus present; proboscis sheath usually extends nearly or quite

to posterior end of body : ; ; ; ; ; ee

Body remarkably thick and massive, usually nearly cylindrical when

fully extended, but very broad and much flattened in intestinal region

when strongly contracted ; ocelli wanting; muscular layers of body

possess a reddish tinge . EUBORLASIA.

ge ; i à ; ;

. Body long and slender, rounded or flattened, very contractile ; ocelli

present in most species : . LINEUS.

. Body rather firm, lateral margins not remarkably thin; incapable of

swimming ; neurochord cells absent in many species . . MICRURA.

. Body usually long and ribbon-like, much flattened, with very thin lateral

margins and well adapted for swimming ; dorso-ventral and diagonal

muscles well developed ; neurochord cells present in many species

CEREBRATULUS.

TANIOSOMA.

. With narrow transverse rings of white throughout length of body.

Body of moderate diameter, but of great length, often exceeding 2

meters, somewhat flattened; brown, with a great number of narrow

rings of whitish encircling the body . T. mexicana Biirger, E.

Without white rings A i ; : : : : 2.

Yellow, thickly sprinkled with small, irregular, dark red spots; body of

very large size, sometimes 2 meters or more in length and 18 mm.

in diameter : ; ‘ ; : T. princeps Coe, A, P.

dish brown, sometimes covered with whitish

bloom ; head with broad spot of darker color and terminal border of

white; ventral surface of same general color as dorsal, but paler,

except ventral side of head, which is whitish ; body large, soft, flabby,

40 to 60 cm. in length T. punnetti Coe, C, S.

432 THE AMERICAN NATURALIST. [VoL. XXXIX.

ZYGEUPOLIA.

Slender, 5 to 10 cm. in length; head acutely pointed ; cephalic furrows

absent, the canal from each cerebral sense organ opening into a small

pit on side of head; caudal cirrus conspicuous ; whitish or flesh-color,

becoming yellowish, rosy, or pale brown in intestinal region and pure

white on head . ‘ : Z. littoralis C. B. Thompson, S, X.

EUBORLASIA.

Of gigantic size for a worm, with a greater diameter than in any other

described species of Nemertean, becoming 45 mm. wide in intestinal

region; dark brown, perhaps with an olive tinge; head paler, with

brown mottlings . i ; í ; E. maxima Coe, E.

LINEUS.

Snout and body not strikingly different in color; without distinct

markings 2.

Snout and body of different bot, or with distinct taani on body 3.

Dusky or brownish green, dark brown, or reddish brown, commonly

paler beneath ; a single row of 4 to 8 ocelli on each side of head

L. viridis (Fabr.) Johnston, A, X, Y.

. Yellowish, pale yellow with tinge of orange, dull orange, ochre, buff, or

yellowish brown; margins of head pale or colorless ; with 3 to 7 irreg-

ular red, purple, or black ocelli, of which the most anterior are largest

avescens Coe, S. —

. With conspicuous median dorsal stripe, but without transverse mark-

ings.

Deep brown or olive, with median dorsal stripe of white or lemon yellow

extending whole length of body and widening out on head to form a

broad white marking . : : L. albolineatus Coe, C, e

Without conspicuous median dori stripe

With one or more narrow transverse rings of are ler A

Without transverse rings of paler color. Pink, rosy flesh-color, or

pinkish red, sometimes with tinge of blue; snout white both a

and below, sharply marked off from rosy color of body ; often with

bluish tinge after preservation 5 L. rubescens Coe, C, S.

. With a single narrow whitish band on dorsal side of head, connecting

posterior ends of cephalic furrows.

Body and head dark reddish brown or purple . L; ry Coe, A

With numerous delicate rings of white or yellowish .

Soft and flabby; deep brown, chestnut, or slaty, sometimes ei green-

No. 463.] NORTH AMERICAN INVERTEBRATES. 433

Drp

» 0.0

"m.

ish tinge; with transverse lemon yellow rings at intervals along whole

length of body and with 7 to 15 very inconspicuous, fine, hair-like

diamond-shaped enlargements of the transverse rings; tip of snout

white, usually with 2 orange colored spots Z. pictifrons Coe, S, E.

Slender ; deep brown, chocolate, or drab, paler beneath, with series of

very narrow and inconspicuous white rings; tip of snout and borders

of cephalic furrows white . : : 5 L. wilsoni Coe, C, S.

MICRURA.

With conspicuous transverse rings of white ; , ; ; 2.

Without conspicuous transverse rings oru 3.

Deep purple or reddish brown above, ns a series af narrow transverse

rings throughout length of body; pure white beneath and on lateral

margins of body; tip of snout Er orange or vermilion ; caudal cirrus

white, conspicuous M. verrilli Coe, A, P, C.

Dusky gray above, with narrow tabem. transverse bands; head flesh-

colored i nr Doe Coe, B.

Dorsal surface with conspicuous a ind blotches .

Without distinct spots, except on tip of snout .

Pale yellow, thickly covered on dorsal surface only with black or a

brown spots and dots, often somewhat elongated and arranged in

irregular longitudinal lines; a single row of 10 to 18 ocelli on each

side of head ; nephridia limited to middle third of nepem region ;

body rather stout, much flattened W. pardalis Coe, C.

Grayish after preservation (color in life RN thickly mottled on

oth dorsal and ventral surfaces with coarse confluent brownish

blotches, which often fuse together posteriorly to form a continuous

brownish color; nephridia extend forward to mouth region

M. nebulosa Coe, A’, 483.

Rosy, flesh-color, or red ; ocelli wanting 6

Olive, ochre, or buff ; ocelli present.

Pale olive brown, grayish ochre, or buff ; deeper brown in intestinal region,

and with a paler median dorsal stripe in esophageal region; 6 to 12 or

more small black ocelli in an irregular row or elongated cluster on

each side of head ‘ M. olivaris Coe, S, C',

Deep red ; tip of snout ws black spot surrounded by narrow ring of

white.

Sometimes purplish in esophageal region and brighter red anteriorly ; head

bright red with a narrow, but very sharp and conspicuous, transverse

band of white just behind tip of snout, which is red with a small, dark

brown or black spot on the exact tip M. nigrirostris Coe, S.

434 THE AMERICAN NATURALIST. | [VoL XXXIX.

6. Paler, without black spot on snout à 7.

7. Rosy or pinkish red with purplish UNE in ee region, becoming

e Pow

xis

gradually paler toward snout, which is white; intestinal region deep

flesh-color, pale red, or yellowish ; accessory buccal glands wanting

M. griffini Coe, S.

. Salmon or flesh-color (rarely light, rosy brown); shading into lighter,

with tinges of brighter red, or nearly white anteriorly ; intestinal lobes

more deeply. colored, sometimes brown ; a cream-colored stripe is situ-

ated in median ventral line; accessory buccal glands well developed

M. alaskensis Coe, A, C, S.

* CEREBRATULUS.

Snout whitish both above and below, strikingly different from deep

color of body í ie any |

Snout not kitingly älteren: (oin body in olor à 3.

. Body very long and ribbon-like, attaining a length d more on two

meters ; deep blood-red, except tip of snout, which is yellowish white,

above and below . à : C. montgomeryi Coe, B, A, P, B’, 85.

Body long and ribbondike, very dark brown or reddish purple. except

head, which is white on both dorsal and ventral surfaces, back about

three fourths the length of the Mie: u or sometimes nearly

or quite to the mouth . . albifrons Coe, A, P, C,

Without distinct longitudinal à or transverse ee on body 4.

With conspicuous transverse or longitudinal markings on bod 9.

Black, brown, reddish brown, olive, or dark gray, sometimes with a

lateral margins 5.

Rosy flesh-color, TEE or bif: -heii paler pesia m land.

nerves reddish and conspicuous in life, intestinal region cream-colored

or pale buff ; body remarkably fragile. C. californiensis Coe, S, S’, 2

Body long and ribbondike 3 ; i ‘

Body comparatively short and road i 8.

Head very long and slender; nephridia vid very numerous rest

ducts.

Dark brown or purplish, paler on borders of cephalic furrows and tip of

snout; head and anterior portions of body very slender, with remark-

ably long and deep cephalic furrows . : . C. longiceps Coe, A.

Head of moderate proportions, or short . 7.

Slaty brown to grayish or pale olive, paler beneath sid often with con-

spicuously paler or white lateral margins

C. marginatus Renier, A, P, C, S, X, Y-

Dark reddish brown; body very large and stout, becoming 2 meters or

more in length and 25 mm. in width; head and cephalic furrows short

C. herculeus Coe, A.

Chestnut brown or reddish in esophageal region, chocolate brown pos-

No. 463] WORTH AMERICAN INVERTEBRATES. 435

Pp w" M ——M e

u a

teriorly ; brownish flesh-color to reddish brown beneath, usually with

median longitudinal ochre stripe along ventral surface

C. occidentalis Coe, A, P.

Brown or olive, ventral surface and lateral margins of body paler; body

. remarkably broad and much flattened, with very thin lateral margins ;

head very broad, with remarkably short cephalic furrows

. Jatus Coe, A, B', A’, P', C', 40-135.

Rather slender ; pale gray with numerous fine, irregular and much inter-

rupted dark olive brown longitudinal lines extending whole length of

body both above and below, but more numerous and larger on dorsal

surface than ventrally . C. lineolatus Coe, S.

Rather short; with conspicuous narrow [eem of dark color in median

dorsal line, and a series of narrow transverse markings of dark color

placed side by side on dorso-lateral aspects of body. Other markings

may possibly be present in life . : . C. signatus Coe, B',

Order Hoplonemertea.!

Body provided with a pair of conspicuous lateral swimming appendages,

or cirri, immediately back of head; posterior extremity broad and

finlike; proboscis without stylets à . NECTON er.

Body without lateral appendages

Proboscis sheath not more than three jours the isch of Baar; bei

long and slender

Proboscis sheath extends er or soit to pair ind of body; ; vai

usuaily not very slen

Proboscis sheath less hai half the length of bay: obont of sal

size

; Biting sheath one half to ie fourt dié jengii of Bode ; pen :

cis well developed PARANEMERTES.

Accessory stylets present 5.

Accessory stylets absent ; procedi i sheath w A RE with

central stylet only ; parasitic CARCINONEMERTES.

Ocelli minute and usually numerous EMPLECTONEMA.

Ocelli large, four in number ; body sitions . NEMERTOPSIS.

Proboscis provided with stylets, intestine not dendroccelous 7

Proboscis without stylets ; intestine dendrocalous ; pelagic

PLANKTONEMERTES. |

I :oboscis sheath without cecal appendages ; proboscis armed with

single central stylet besides 2 ‘or more anon of accessory ao

1 In addition to the marine Nemerteans here included, a representative of the

fresh-water genus (Stichostemma) has been found in pools in the vicinity of Seat-

tle, Washington.

436 THE AMERICAN NATURALIST. [Vor. XXXIX.

7. Proboscis sheath provided with cecal appendages ; proboscis armed

with central plate bearing a number of stylets besides several pouches

of accessory stylets °. . DREPANOPHORUS.

8. Ocelli numerous, extending poitiriody dig lateral nerve cords beyond

the brain ; basis of central stylet massive, with flattened or concave

posterior iia i i ZYGONEMERTES.

8. Ocelli do not extend posietioity TREE bos: basis of central die

commonly (but not always) rounded posteriorly . 9.

9. Body usually not very small ; ocelli usually numerous, alway more than

4 in the known Pacific est species . . AMPHIPORUS.

9. Body very small; ocelli usually 4, ipd in ioiai, occasionally

each of the four ocelli-is double or fragmented into groups ; rarely

ocelli are entirely wanting . : i , : . TETRASTEMMA.

EMPLECTONEMA.

1. Dorsal surface green; central and accessory stylets curved ; ini long

and slender; basis very long ; body dark or pale green dorsally ; whit-

ish, yellowish, or very pale green ventrally

E. gracile (Johnston) Verrill, B, A, P, C, Y.

A B C D E F

Fic. 1.— Outlines of — oe and bases.

A,E rare a grac E, rtes albide

E E. bürger F, 2; thalassina

E. purpuratum G, Z. virescens.

DR: gurfnratum. Central stylet more highly magnified.

No. 463] NORTH AMERICAN INVERTEBRATES. 437

1. Dorsal surface brown or purplish ; central and accessory stylets papa

2. Stylets short, with swollen heads; basis of central stylet swollen i

rounded posteriorly ; 11 proboscidial nerves ; dark brown above, often

with minute purple dots ; flesh-colored or yellowish white beneath

. bürgeri Coe, A, P.

2. Stylets without swollen heads, fluted longitudinally ; basis of central

“pP

stylet not swollen posteriorly; 16 proboscidial nerves ; purplish or

purplish brown from closely placed oe on dorsal surface ; ven-

tral surface gray or yellowish . . . E. purpuratum Coe, B.

NEMERTOPSIS.

Filiform, often 15 cm. or more in length ; very pale brown or whitish, with

2 longitudinal dorsal stripes of deep brown ; 8 proboscidial nerves

N. gracilis Coe, C.

T CARCINONEMERTES.

Length when sexually mature but 4 to 6 mm. ; with 2 large ocelli ; orange

or reddish ; parasitic on egg masses of diee productus and per-

haps other crabs . ‘ ; C. epialti Coe, C

PARANEMERTES.

White or flesh-color ‘ : 7 \ "d v

With orange, green, brown, or aspe tints . à ; « 2 X

With 2 or 4 pouches of accessory stylets; 14 proboscidial nerves;

stylets have braided appearance; purplish brown, dark brown, or

orange brown above, on sides, and on lateral margins of ventral sur-

face; with a whitish angular spot on each side of head; ventral

surface, often median third only, white or yellowish white

P. peregrina Coe, B. A, P, C s.

With 4 or 6 pouches of accessory stylets; 10 large proboscidial nerves ; ,

translucent; pale orange anteriorly ; flesh-color, grayish, or very pale

re posteriorly, much obscured i er green color of intestinal

P. californica Coe, S.

ub 4 ponches ol icceiaory BT ; 3 or 10 rons nerves ;

opaque white . P. pallida Coe, A

With 6 or 12 pouches of ücoesóty sles ; 11 or 12 proboscidial nerves ;

whitish, pinkish, or flesh-color — . P. carnea Coe, A, P.

ZYGONEMERTES.

Central stylet short and stout .

Central stylet rather slender.

438 THE AMERICAN NATURALIST. (VoL. XXXIX.

Whitish, with tinge of yellow ; ocelli extend along lateral nerves for about

two fifths the length of esophageal region ; body small

Z. albida Coe, P.

2. Pale green; occasionally flesh-colored, pale yellow, or white, especially

anteriorly ; central stylet short, about half as long as basis, not remark-

ably stubby ; usually 2 or 3 accessory stylets in each of 2 lateral

pouches; 1o or 11 proboscidial nerves

Z. virescens (Verrill) Montgomery, C, S, X.

A B © D E

Fic. 2.— Outlines of central stylets and bases.

A, Paranemertes carnea.

i E, P. pallida.

B, P. californica. : F, Carcinonemertes epialti.

C, P. californica. Stylet only, more highly magnified. G, N: topsis gracili.

D, P. peregrina,

2. Dark olive green ; central stylet remarkably stubby, often less than half

as long as basis which is much serrated on posterior border ; commonly

5 accessory stylets in each of 2 lateral pouches; 12 proboscidial nerves

. thalassina Coe, A.

AMPHIPORUS.!

1. Body very gelatinous, with an enormous development of the body

parenchyma. .

Body short and broad ; ocelli large, 30 or more on each side of the head ;

cerebral sense organs extremely small, situated in front of brain

A. gelatinosus Coe, A', 159.

‘In addition to the forms here included, two species, 4. brunneus and A.

drepanophoroides, have been described by Griffin from Puget Sound, but their

agnoses are so incomplete that it is doubtful as to which, if any, of these forms

they should be referred

No.463] WORTH AMERICAN INVERTEBRATES. 439

. Body contains only a moderate amount of parenchyma 2.

2. Esophagus provided with large caecum extending on ene side of

esophagus proper and ending blindly posteriorly

Fic. pe Outlines Hi puis showing number and arrangement of ocelli.

A , P na

latus; br, brain, cv, dv, lv, cephalic, dorsal, and latera! vessels respectively.

B,+

C, A. ch 25ilis.

. Imparispßinosus.

2. Esophagus without ventral caecum . 3.

3. Proboscis usually provided with only two ‘pouches ol accessory stiet 4.

3. Proboscis provided with more than 2 pouches of accessory stylets 16.

4. Ocelli in a single row on each side of head.

A B C D A FK G

Fic. 4.—Outl f central stylets and tases.

A, A Pip abd de E, A. uentatur,

B, A. bimaculatus. F, A. similis.

C, A. tigrinus. G, A. impar ispinosus

D, A. nebulosus.

440 THE AMERICAN NATURALIST. [Vor. XXXIX.

Body rather slender; 10 to 25 mm. in length ; color yellow ; blood vessels

deep red in color; basis and stylet both very slender and of about

3009020»

equal len 4 : : . A. cruentatus Verrill, C, S, X.

Ocelli scattered, and not in a single row on each side of hea 5.

Central stylet as long as basis, or considerably longer . A ae,

Central stylet considerably shorter than basis . i : A cz Mb

Central stylet and basis of about equal length Ä à : E i

. Central stylet about twice as long as basis — . : : i T £

. Body rather broad and flattened ; orange, brownish, or reddish above,

with 2 large dark brown or black elongated spots on head ; ventral sur-

A B Ç

Fic. 5.— Outlines of stylet apparatus.

A, Amphiporus formidabilis, with 12 pouches of accessory stylets.

B, A. Punctatulus, with 2 pouch f y stylets.

C, A. impar isPinosus, with 3 pouches of y stylets.

face pale orange or flesh-color ; sometimes with 4 pouches of accessory

stylets ; stylets very slender; 14 or 16 proboscidial nerves; cerebral

sense organs beside brain . ‘ . A. bimaculatus Coe, A, P, C.

7. Body rather short and thick; mottled thickly with dark brown dots and

A. punctatulus Coe, S (at surface).

8. Cerebral sense organs in front of brain . : ; ; à . 9.

8. Cerebral sense organs beside brain.

Body short and broad ; color reddish or brownish above, pale beneath ;

! In a single species (A. leptacanthus) belonging to this group the relative length

of stylet and basis is as yet unknown, and the species is not included in this key.

Color of body whitish, with tinge of yellow or brown; basis of central stylet

remarkably slender, four or five times as iong as broad ; ocelli 16-24 in a single

irregular cluster on each side of head.

No. 463] NORTH AMERICAN INVERTEBRATES. 441

basis rather slender, or ordinary neni 14 proboscidial nerves; cere-

bral sense organs very large . pacificus Coe, B', A', C!, 47-97.

9. With numerous spots and € on peas surface.

Rather broad and flat ; whitish, thickly mottled with dark brown blotches

and dots; ventral surface whitish ; basis of central stylet bell-shaped.

broad and flattened posteriorly ; stylets slender; 17 proboscidial nerves

A. nebulosus Coe, A.

9. Dorsal surface without distinct spots . ;

10. Red, orange, brown, or purplish above; RET or whitish ur 22.

10. Whitish, flesh-color, yellow, or pale reddish 12.

11. With 17 to 20 proboscidial nerves ; basis of odes proportions ;

body short and broad ; dark purplish or chocolate brown above, with a

A B E D

Fic. 6.— Outli f heads, showi and arrangement of ocelli.

A, itt oc and si cel of anh = ventral ec of head respec-

Que de dorsal re + cee; m, lateral n

B, Amph P atus.

^ A. bima:

D, As de: c, cerebral sense organ.

triangular white spot on each vm of head ; ventral surface pinkish or

; flesh-color . A. angulatus (Fabr.) Verrill, B, A, P, X.

11. With 10 to 12 oiobestiüial n nerves ; body small, rather short and broad ;

reddish or orange, paler beneath ; ocelli usually only 4 to 8 on each

side of head ; basis conical, stylets slender.

A. cali fi Coe, S, S’, 50.

12. With 10 or 1I Arie nerves 13

12. With 15 proboscidial ne

Whitish ; very slender ; ER glands " developed ; intestinal

caecum short A. paulinus Punnett, B.

13. Small; of moderate caoporions | whitish, “pale flesh-color, yellowish,

ochre, or pale orange ; ocelli commonly 10 to 50; basis of central stylet

bell-shaped ; 10 or II proboscidial nerves . A. flavescens Coe, C, S.

. Very small and slender ; whitish ; ocelli commonly 10 to 20, in four

groups; I to 3 accessory stylets in each pouch; 10 proboscidial nerves

A. similis Coe, C.

(A)

14. Central stylet about three fourths as long as basis.

442 THE AMERICAN NATURALIST. [Vor. XXXIX.

Body small, slender, rounded ; brownish, with minute dark brown dots ;

25 or more ocelli; basis of central stylet bell-shaped ; cerebral sense

organs large, situated close in front of brain . A. fulvus Coe, S

14. Central stylet not more than half as long as basis : 15.

15. Central stylet about half as long as basis.

Body rounded, rather slender; color of females yellowish orange, ob.

scured in intestinal region by dark green ova in breeding season ;

males yellowish, with white flecks ; basis massive, rounded posteriorly ;

cerebral sense organs in front of brain ; . A. tigrinus Coe, P.

15. Central stylet about one third as long as the remarkably massive basis.

Body short and rounded ; proboscis remarkably large, provided with 10

nerves ; basis larger than in any other known species, measuring about

a millimeter in length and easily visible to the unaided eye; stylets

short and conical x : : 1. macracanthus Coe, N.

: A B ra D E

Fic. 7.— Outlines of central stylets and bases,

i ; midabilis. D,A

B, A. functatulus, E, A. flavescens.

C, A. leßtacanthus, F, A. macracanthus.

16. With 3 pouches of accessory stylets. ;

White ; body slender ; ocelli usually less than 40; commonly 4 to 8 neph-

ridiopores on each side, some of which are situated on dorsal side of

body . - ; i € A. imparispinosus Coe, B, A, P, C, S.

16. With 4 or more pouches of accessory stylets ; . . 17.

17. With 4 (or sometimes 2) pouches of accessory styles. . . 18.

17. With 6 to 12 pouches of accessory stylets.

Body very slender ; color whitish or flesh-color ; ocelli usually 60 to 250;

commonly 20 or more nephridiopores on each side, most of which are

situated on dorsal side of body . A. formidabilis Coe, B, A, P, C.

18. Orange, brownish, or reddish above, with 2 large dark brown or black

No. 463] WORTH AMERICAN INVERTEBRATES. 443

angular spots on head ; ventral surface pale orange or flesh-color ; 14

or 16 proboscidial nerves : ; A. bimaculatus Coe, A, P, C.

18. Dark brown or purplish, with small, angular white spot on each side of

head; ventral surface pink or flesh-color; 17 to 20 proboscidial

nerves ; occasionally with 4 pouches of accessory stylets

A. angulatus (Fabr.) Verrill; B, A, P, X

19. Esophageal czcum terminates posteriorly in front of anterior ends of

intestinal caeca ; ben parenchyma comparatively well developed ;

ocelli few . A. rubellus Coe, S', 20-50.

19. Esophageal caecum etin: oy far beyond anterior ends of

intestinal caca ; mii Pr but little developed ; ocelli numer-

ous } A. occidentalis Coe, P', 40-97.

TETRASTEMMA.

1. With 4 well developed ocelli 2.

1. Ocelli fragmented or wanting ` : : é A ; ee

B. T. quadrilineatum.

C, T. nigrifrons.

F, T. reticulatum.

2. Body not especially firm, somewhat flattened 3.

2. Body remarkably firm, cylindrical (CinsrEDIA. y B.

3. With distinct longitudinal brown stipes on dorsal ‘surface 4.

3. Without distinct longitudinal stripes of brown on dorsal surface. 5.

4, Flesh-color, creamy, or grayish, with 2 deep brown longitudinal stripes

on dorsal surface ; 5 to 10 mm. in ength . T. bilineatum Coe, S

4. Whitish, with 4 deep brown longitudinal stripes, of lt 2 lie on lat-

surface ; 8 to 12 mm. in len

"€ vim T. quadrilineatum Coe, S.

. * . 6.

5. Blood corpuscles distinctly red

444 THE AMERICAN NATURALIST. (VoL. XXXIX.

5. Blood corpuscles pale or colorless.

Body very slender, usually 10 to 15 mm. in length ; milk-white, creamy,

or flesh-colored; basis of central stylet very slender; cerebral sense

organs remarkably large, situated beside brain

T. albidum Coe, C, S.

6. With large black or deep brown marking on dorsalsideof head . 7.

6. Head without conspicuous marking.

Body 30 to 60 mm. in length ; brownish red above with median white

stripe; ventral surface white ; without conspicuous lateral grooves on

e ; * ` ; T. bicolor Coe, A.

7. Cephalic marking wreath-like.

Rather slender, 15 to 25 mm. in length ; reddish brown both above and

below, except head which is white with a sharply marked wreath of

deep brown color on dorsal surface : ; Zu signifer Coe, S.

7. Cephalic marking triangular or shield-shaped.

Fic. 9.— Outline of central stylet and bases.

A, Tetrast Baer

B and C, T. nigrifrons. F, T. reticulatum.

D, T. quadr lineatum.

Usually 20 to 70 mm. in length ; head provided with two pairs of very

conspicuous, lateral, oblique furrows. Color very variable, except head

which is white with shield-shaped or triangular marking of deep brown

color on dorsal surface. Body deep purple, deep brown with white

dorsal longitudinal band, reddish with brown flecks, pale brownish, or

on dorsal surface ; of similar color, but paler, and often with white

longitudinal band, on ventral surface : . I. nigrifrons Coe, C.

8. Flesh-color or yellowish, mottled, especially on dorsal surface, with brown-

ish blotches and dots of various shades, often mainly collected into a

series of transverse bands ; body slender, 8 to 15 mm. in length

T. (Gzrstedia) dorsale (Abildgaard) McIntosh, C, X, Y.

No. 463] NORTH AMERICAN INVERTEBRATES. 445

8. White, with large, en and longitudinal, dark brown markings

almost covering dorsal surface; often with 16 pairs of rectangular

marks and pair.of lateral piens lines in addition to bilobed marking

on dorsal surface of head ; in some varieties markings fuse together ;

body slender, 8 to 15 mm. in length

T. (Gzrstedia) reticulatum Coe, S.

9. With four groups of fragmented ocelli.

Body usually less than 12 mm. in ke er, ge yellow ; 12 proboscidial

nerves T. aberrans Coe, A.

9. Ocelli an: herhaphrodite:

Body 5 to 10 mm. in length; whitish or very pn d uns probably

parasitic in Tunicates i um Coe, A.

DREPANOPHORUS.

Ocelli numerous, of very large size ; length of body 5 to 10 cm. ; dorsal

surface dull reddish or orange, thickly covered with fine brownish dots ;

ventral surface flesh-color with tinge of orange

D. ritteri Coe, S', 50-150.

PLANKTONEMERTES.

Body broad, much flattened, gelatinous and hyaline ; intestinal diverticula

numerous ; median dorsal vessel present ; length 14 to 47 mm. ; orange

orpink . ; à . P. agassizii Woodworth, E (sorteo)

NECTONEMERTES.

Professor Heath of Stanford University informs me that a species of this

remarkable genus has very recently been collected in Monterey Bay, Cali-

fornia. Its specific diagnosis has not yet been published.

Order Bdellonemertea.

Sucking disk present at posterior end of body; intestine coiled, without

caecum or lateral diverticula ; parasitic in various species of pelecypods

MALACOBDELLA.

A single species of this genus has been recorded from California, but it

has not yet been studied sufficiently to determine whether it is identical

either with M. grossa of the eastern coast of North America and Europe

or with M. japonica of Japan.

446 THE AMERICAN NATURALIST. (Vor. XXXIX.

LITERATURE.

Although the number of species recorded from this region is so large

they are all described in the following papers : —

BÜRGER, O.

'93. Südgeorgische und andere exotische Nemertinen. Zoöl. JaAró.,

Abth. Syst., vol. 7, pp. 207-240.

(Describes Zienzosoma (Eufolia) mexicana from the west coast of Mexico.)

CoE, W. R.

:01. Papers from the Harriman Alaska Expedition, XX, The Nemer-

teans. Proc. Washington Acad. Sci.,vol. 3, pp. 1-110, pls. 1-13.

Reprinted with the same pagination and plates in the Harriman

Alaska Expedition, XI, 1904.

(Contains detailed descriptions of 32 species, 23 of which are illustrated by col-

ored figures. Nearly all have full descriptions of anatomical peculiarities. There

are several plates of anatomical details )

CoE, W R.

:04. Nemerteans of the Pacific Coast of North America, Part Il.

Harriman Alaska Expedition, XI, pp. 111-220, pls. 14-22.

(In this paper 21 species are enumerated in addition to those mentioned in the

first portion of the report. These were collected mainly on the coast of Cali-

fornia. Some 18 species are described as new to science, all except one of which

are illustrated by colored figures.)

CoE, W. R.

:05. Nemerteans of the West and Northwest Coasts of North America.

GRIFFIN, B. B.

98. Some Nemerteans of Puget Sound and Alaska. Ann. New York

Acad. Sci., vol. 11, pp. 193-217.

(A posthumous paper containing brief diagnoses of 12 named species.)

No. 463.] NORTH AMERICAN INVERTEBRATES. 447

PUNNETT, R. C.

:01. Arctic Nemerteans. Proc. Zool. Soc. London, 1901, pp. 90-107,

ls. 6-7.

(Contains a description of one species, Amphiporus paulinus. from the Pribilof

Islands, and mentions one other from the Commander Islands.)

STIMPSON, W.

57, Proc. Acad. Nat. Sci. Phila., 1857, pp. 159-165.

(Three species recorded from Pacific coast.)

WOODWORTH, W. McM.

'99. Preliminary Account of Planktonemertes agassizii, à New Pelagic

Nemertean. Bull. Mus. Comp. Zoól.. vol. 35, PP- 1-4 pl. 1.

In addition to the papers mentioned above, which contain records of the

species found on the Pacific coast, many of the species which occur both

there and in other regions are described and figured in Bürger's Monograph

of the Nemerteans of the Gulf of Naples, in. Joubin's monograph in the

Fauna Francaise, in McIntosh's British Annelids, in Verrill's monograph

of the New England Nemerteans in the Zransactions of the Connecticut

Academy, and in other well known works.

SHEFFIELD SCIENTIFIC SCHOOL

YALE UNIVERSITY.

STUDIES ON THE PLANT CELL. — VI.

BRADLEY MOORE DAVIS.

SECTION V. CELL ACTIVITIES AT CRITICAL PERIODS OF

ONTOGENY IN PLANTS.

We shall discuss in this paper the behavior of the protoplasm

at a number of critical periods in the life history of plants when

the organism passes from one phase to another of a fundamen-

tally different character. At such times great changes take

place in the potentialities of the cells which inaugurate the new

developments, changes that are generally most conspicuously

shown in the structure of the nucleus. Some of the most inter-

esting events of cell and nuclear history take place at these

times, as would be expected from the importance of the phe-

nomena. We shall treat the material under the following heads: `

(1) Gametogenesis, (2) Fertilization, (3) Sporogenesis, (4) Re-

duction of the Chromosomes, (5) Apogamy, (6) Apospory, (7)

Hybridization, (8) Xenia.

I. GAMETOGENESIS.

The events of gametogenesis are clearly known for the higher

plants but there is some confusion and almost no detailed infor-

mation in the accounts of the thallophytes where the nuclei are

very small and the details of the mitoses preceding the forma-

tion of sexual cells exceedingly difficult of study.

There is complete agreement among all investigators that the

mitoses which precede the differentiation of gamete nuclei in

spermatophytes, pteridophytes, and bryophytes are typical karyo-

kinetic figures not differing essentially in the behavior of the

chromosomes from the mitoses generally characteristic of the

gametophyte generation. This information is based upon a

449

450 THE AMERICAN NATURALIST. (VoL. XXXIX.

large number of studies of nuclear figures in antheridia 'and

archegonia, the generative cell of the pollen tube and micropylar

region of the embryo-sac. There are no reduction phenomena

in these higher groups at the period of gametogenesis.

The subject is complicated in some types of spermatophytes

where the gametophyte phase is so reduced that the mitoses

which precede gametogenesis may follow immediately upon the

two mitoses characteristic of sporogenesis or be separated from

them by only one or two divisions. For example, it is known

in several types of the lily family (Lilium, Tulipa, Fritillaria,

Erythronium, etc.) that the two mitoses of sporogenesis (hetero-

typic and homotypic) are included in the embryo-sac and become

a part of that gametophyte history. The third and final mitosis

in this history differentiates the egg in the micropylar end of

the embryo-sac and is a typical nuclear division. This subject

was treated in some detail in Section III of these * Studies "

(Amer. Nat., vol. 38, pp. 741-745, 1904). When the mitoses of

sporogenesis are not included within the embryo-sac we find

almost without exception three typical mitoses preceding the

differentiation of the egg in the angiosperms and a very large

number in the gymnosperms, and of course in the pteridophytes

and bryophytes the whole vegetative period of the gametophyte

which is generally green and self-supporting. There are from

two to three mitoses in the pollen grain and male gametophyte

of the angiosperms before the development of the sperm nuclei

and a somewhat larger and more variable number among the

gymnosperms. It is necessary at the outset to understand

clearly what are the events of gametogenesis in spermatophytes

because several authors have carried the phenomena of sporo-

genesis over into the period of gametogenesis, where it can

have no proper place in exact morphology. Such papers will

be treated in connection with * Sporogenesis" and ** Reduction

of the Chromosomes," for they concern primarily these phe-

nomena alone.

Gametogenesis must be considered at present chiefly from

our knowledge of the conditions in the higher plants as they

furnish almost the only detailed information that we have on

the subject. Upon this as a basis we are justified in suggesting

No. 463.] STUDIES ON PLANT CELL.— VI. 451

possibilities in the thallophytes which must remain as specula-

tions until investigations have advanced much farther in this

difficult field of cell study. The basis of any theories at present

must be phylogenetic, a principle that has not been followed in

some of the work upon the thallophytes.

Gametogenesis in plants is full of interest TNNT of the

sharp differences from the processes of spermatogenesis and

oógenesis in animals. In animals the period of gametogenesis

is one of unusual activity. After the germ cells are differenti-

ated there follows a period of cell growth, with the peculiar

activity termed synapsis, during which the number of chromo-

somes is reduced to one half the number characteristic of the

species. The germ cells emerge from the growth periods as

primary spermatocytes or oócytes which give rise respectively

by two successive mitoses to four spermatids or to an egg with

its accompanying polar bodies. The gametes have one half the

number of chromosomes characteristic of the species, so that

the period of gametogenesis is one of chromosome reduction.

The character of this process of reduction will be considered

when we take up the analogous phenomena in plants after the

discussion of sporogenesis. Gametogenesis in plants is in strik-

ing contrast to that in animals. In all higher groups (those

above the thallophytes) we know that the gametes have the

same number of chromosomes as the vegetative cells of the

parent plant (gametophyte). There is no reduction of the chro-

mosomes at the time of gametogenesis, that phenomenon taking

place at the end of the sporophyte generation with sporogenesis.

Also, there are no peculiarities of the mitoses immediately

preceding gametogenesis excepting such as concern the devel-

opment of cilia-bearing organs (blepharoplasts) or slight pecul-

iarities in the form or size of the spindles, for such nuclear

figures are frequently different in these particulars from the

mitoses in vegetative cells of the gametophyte. The differences

concern chiefly the structure of the sperm, and have been de-

scribed in our account of that structure (Amer. Nat., vol. 38,

July and August, p. 576. 1904).

To Strasburger above all others should be given the credit

of making clear these important characteristics of gametogene-

452 THE AMERICAN NATURALIST. [Vor. XXXIX.

sis in plants. Strasburger’s paper of 1894 on “ The Periodic

Reduction of the Number of Chromosomes in the Life His-

tory of Living Organisms " (Annals of Bot., vol. 8, p. 281) was

the first elaborate presentation of the principles of gametogene-

sis and reduction phenomena in plants and has become classical

as the foundation of the present attitude in botanical science

and the basis and stimulus of a large amount of confirmatory

research. The matter really crystallized after the discovery that

the sporophyte generation of the higher plants possessed nuclei

with twice the number of chromosomes characteristic of the

gametophyte and that the reduction took place in the spore

mother-cell just previous to sporogenesis.

These facts were gradually established by a number of investi-

gations beginning with Strasburger (84, '88) and Guignard ('84,

385). Guignard (’91) presented the first complete count of the

number of chromosomes in the life history of a plant (Lilium

martagon), determining the reduction period to be in the spore

mother-cell, and Overton ('93 a and b) independently reached

the same conclusions for the same plant and extended the knowl-

edge of the chromosome count in gametophyte and sporophyte

to a number of other types. Overton’s paper was important in

its suggestiveness for extended research among the higher cryp-

togams. Other investigations followed shortly in the gymno-

sperms, pteridophytes, and liverworts, all supporting the view

that the nuclei of the sporophyte generation, following the fusion

of gamete nuclei, had double the number of chromosomes char-

acteristic of the gametophyte and that the reduction phenomena

occurred at the end of the sporophyte generation in the spore

mother-cell. The significance of reduction phenomena at sporo-

genesis must be phylogenetic since it represents a return of the

organism at this time to the ancestral gametophyte condition.

The details of this literature belong to the account of “ Sporo-

genesis ” and “Reduction of the Chromosomes,” and will be

taken up later. But it is necessary to present the outline at

this time to make clear the important fact that no reduction of

the chromosomes takes place during gametogenesis in all groups

above the thallophytes.

The theories of gametogenesis among the thallophytes rest

No. 463.) STUDIES ON PLANT CELL.— VI. 453

upon information which in point of completeness falls very far

short of our knowledge of the groups above. Indeed, no forms

have been studied with the detail that is known in higher groups

chiefly for the reason that the investigator is forced to deal with

very small nuclei and mitotic figures whose chromosomes are

exceedingly minute and because of various technical difficulties.

The theories in general fall into two groups: (1) those which

have an obvious basis in attempts to reconcile events with the

processes of gametogenesis in animals, and (2) those proceeding

from the view that for phylogenetic reasons the periods and phe-

nomena of gametogenesis in the lower plants should correspond

with those of the higher.

We may pass over with a few words the early crude attempts

to establish structures for plants comparable to the polar bodies

of animals. For example at the conclusion of oögenesis in some

algae (e. g., Vaucheria, CEdogonium) a globule of slime is exuded

with the opening of the oógonium. It was suggested that such

material is thrown off from the egg but we now know that it is

not protoplasmic in character but is apparently derived from a

softening of the cell wall. Then the ventral canal cell has been

compared to a polar body but it seems clear now that all of

the canal cells are homologous and a part of what was form-

erly an extensive gametogenous tissue within the archegonium.

Then the small group of cells cut off below the oógonium of the

Charales and the fragmented nuclear material in the trichogyne

of the red algze have been compared to substance thrown off

from the egg but without any knowledge of the nuclear struc-

ture. Finally the nuclear degeneration which is a very conspic-

uous feature of oógenesis in certain groups whose oógonia are

multinucleate (Peronosporales, Saprolegniales, Pelvetia, etc.)

has been considered related to reduction phenomena. But the

nuclei in all of these forms bear every evidence of being in each

type homologous structures whose large numbers have a phylo-

genetic raison d'étre and the extensive degeneration is associated

with the principles of sexual evolution which tend to conserve

protoplasm for the good of a lesser number of gamete nuclei

even to the sacrifice of others that are potentially equivalent.

We will now consider the few instances among the thallo-

454 THE AMERICAN NATURALIST. (Vow. XXXIX.

phytes in which a reduction of the chromosomes is reported just

previous to or during gametogenesis. The best known case is

Fucus since this type has been studied by three investigators :

Farmer and Williams (98) and Strasburger ('97a). They agree

in describing the nuclear figure that differentiates the oógonium

from the stalk cell as exhibiting a large number of chromosomes

(28 or 30) while the three mitoses within the oógonium, which

give rise to the eight eggs, present only one half that number

(14 or 15). Apparently there is a reduction by one half just

before the mitoses in the oógonium. Since there is no sporo-

phyte generation in Fucus itis of course difficult to compare

these conditions with those in higher plants, but, as will be

explained later, there are some reasons why we should not

expect to find reduction phenomena at gametogenesis in any

thallophyte.

Reduction phenomena at gametogenesis have also been sug-

gested for various types of the Peronosporales and Saproleg-

niales but not, however, in exactly the same way as in Fucus.

There are always, as far as is known, one or two mitoses within

the oógonium before the gamete nuclei are organized and it has

been held that these are reduction divisions by Rosenberg for the

Peronosporales and by Trow for the Saprolegniales. Rosenberg

(: 03b) described for the oógonium of Plasmopara a condition of

synapsis in the nuclei preceding the two mitoses and compared

this sequence with the events of sporogenesis in higher plants

in which the two divisions within the spore mother-cell are pre-

ceded by a period of synapsis. Rosenberg did not determine the

number of chromosomes in the vegetative nuclei so that he has

no positive evidence of reduction in the oógonia. With respect

to the two mitoses and the preliminary synapsis I have already

pointed out in criticism of Rosenberg's studies (Bor. Gaz., vol.

36, p. 154. 1903) that the number of mitoses is variable in the

oógonia of the Peronosporales and Saprolegniales and apparently

entirely absent in the species of Vaucheria studied by myself

(Davis, :04a). Also, the phenomenon of synapsis, which is

easily recognized in the large nuclei of the spore mother-cell,

would be difficult to establish in the small nuclei within the

oögonia of the forms mentioned above. Nuclei can be found

No. 463.] STUDIES ON PLANT CELL.— VI. 455

in a number of structures with their contents somewhat massed

at one side or in the center but such conditions must not be

confused with the remarkable process of synapsis in the spore

mother-cell. Among all the excellent studies of gametogenesis

in the Peronosporales I cannot find any clear evidence of a re-

duction of the chromosomes at gametogenesis.

Quite different is the account that Trow (:04) brings forward

to support his view of chromosome reduction during gametogen-

esis in the Saprolegniales. Trow describes two mitoses in the

oógonium of Achlya debaryana : in the first the number of chro-

mosomes is eight which becomes reduced to four in the second.

Trow's account of a second mitosis in Achlya is very different

in a number of particulars from the results of all investigations

on gametogenesis in the Peronosporales and Saprolegniales.

Two centrosomes with radiations are said to appear at the poles

of the spindle at anaphase, structures which were not present in

the first mitosis. Some of these asters become the center of

the egg origins and are later accompanied by deeply staining

material constituting a body which Trow terms an ovocentrum

and which perhaps corresponds to a coenocentrum. Relatively

few of the nuclei in the oógonium are said to pass through this

second mitosis and some of their products, with the accom-

panying asters, break down. The remainder become the func-

tional gamete nuclei of the eggs. There are many complex

activities described by Trow in connection with the appearance

of the asters during the second mitosis and also at the side of

the sperm nuclei which are said to enter the oógonium, events

that cannot be correlated with the processes of gametogenesis

and fertilization as we understand them for the Peronosporales,

They are treated briefly in a review | myself (Bor. Gas vol.

39, p. 61, 1905), where, however, I misunderstood a distinction

that Trow draws between the aster and the ovocentrum (see an

answer by Trow, Bot. Gaz., vol. 39, p. 300, 1905). My impres-

sion is that either Trow has been mistaken in his interpretations

conception of gametogenesis is in the Saprolegniales and Perono-

sporales, but which are not fully explained by Trow's paper.

Let us now think of gametogenesis among the thallophytes

456 THE AMERICAN NATURALIST. (VoL. XXXIX.

with reference to what we know of the process in higher groups

and the principles of the origin and evolution of sex and the

sporophyte among the lower. It seems clear that the sporo-

phyte generation is characterized by a double number of chromo-

somes as a result of the fusion of gamete nuclei at fertilization.

We must then lay the fundamental inception or origin of the

sporophyte to the stimulus of the sexual act. That is, the sexu-

ally formed fusion cell must have different potentialities from

the germ plasm of the parent gametophyte and it cannot pro-

duce a gametophyte again until these potentialities are worked

off and the protoplasm returns to the dead level of the ancestral

stock (the gametophyte). By the potentialities of the sporo-

phyte plasm we mean primarily a greater energy or growth

stimulus which must express itself differently from the gameto-

phyte. Morphologically we can only distinguish sporophyte

plasm from gametophyte plasm by the double number of the

chromosomes but of course the complexities of the sexual act |

would make great differences in the chemical structure of the

two. The divergences in the history of the gametophyte and

sporophyte, as shown throughout ontogeny and phylogeny, are

but the final expressions of the different potentialities of the

protoplasm in each generation. The morphological forms of

expression of the sporophyte are extraordinarily various and in

the long evolutionary history of this generation have developed

great structural differentiation but with every life history the

sporophyte has the same beginning (fertilization, with the doub-

ling of the chromosomes) and the same ending (sporogenesis,

with chromosome reduction). Between the beginning and the

end is intercalated a vegetative period, short and simple in some

forms, and very long and elaborate in others. The history of

the development of this vegetative period or the evolution of

the sporophyte is a subject far outside of and secondary

to the scope of this discussion. We are only concerned with

the protoplasmic activities at the beginning (fertilization) and

the end (sporogenesis) of the sporophyte generation.

We know nothing of ‘the behavior of the chromosomes in

ore of the thallophytes which illustrate most closely our con-

ception of the origin of sex and of the sporophyte generation.

No. 463.] STUDIES ON PLANT CELL.— VI. 457

I refer to many lower alge such as Ulothrix, forms of the

Volvocacex, CEdogonium, Coleochzte, and many others. How-

ever, the homologies of primitive gametes and their origin from

types of asexual zoóspores is very clear in a number of groups.

We can see nothing in the morphology and mode of develop-

ment of these reproductive cells to suggest reduction phenomena

when gametes are produced. The primitive gamete is generally

somewhat smaller than its homologue the zoöspore, often because

the protoplasm of the gamete mother-cell becomes distributed in

a greater number of daughter elements. It is well known that

the conditions that lead to conjugation are exceedingly variable,

depending upon environmental factors and one often cannot tell

at the time whether a swarm spore will show sexual habits or

germinate without conjugation. The most satisfactory theory

of the origin of sex in plants regards primitive gametes as

weaker or lacking in certain potentialities of vegetative growth

and the conjugation as a mutually coóperative process resulting

in a rejuvenescence of the protoplasm. The fact that many

simple types of gametes will germinate without fertilization and

produce small and weak sporelings shows that vegetative possi-

bilities are not entirely lost. Investigations on the chromosome

history among these forms, difficult though they be, are some of

the most interesting subjects of botanical research. We know

some general principles of the origin and evolution of sex in

plants (Davis, :oıb, :03a) but of the chromosome history in the

simplest types of gametogenesis nothing is known.

With respect to the history of the chromosomes in the sim-

plest sporophytes we are also as ignorant as in the simplest

types of gametogenesis. We have excellent reasons for believ-

ing that the sporophyte generation is represented among the

thallophytes in a number of very simple conditions. Numbers

of zygospores and oöspores (^. £. Ulothrix, CEdogonium, forms

of the Conjugales and Volvocacez, etc.) give rise on germination

to several daughter cells. In higher forms this growth period is

lengthened to the formation of a reproductive tissue (Coleochzte)

and in the great groups of the Rhodophycez, Ascomycetes, and

Basidiomycetes there is present an extensive development from

the fertilized female cell (or its equivalent when apogamy obtains)

458 THE AMERICAN NATURALIST. | (VoL. XXXIX.

involving the development of a vegetative structure before the

period of sporogenesis. From the studies of Wolfe (:04) we

know that the sporophyte portion of Nemalion (the cystocarp)

contains nuclei with double the number of chromosomes (about

16) present in the gametophyte (about 8) and that the period of

chromosome reduction is apparently just previous to the devel-

opment of the carpospores (sporogenesis). Williams (: 04a and

b) has recently determined that the asexual plant of Dictyota is

' a sporophyte generation with double the number of chromosomes

(32) found in the sexual plant (16). The reduction occurs here

during a rather long period of preparation on the part of the

nucleus in the tetraspore mother-cell and the reduced number

appears in the two mitoses that form the tetraspores. These

events closely parallel those in the spore mother-cell of higher

plants and will be discussed further under “ Sporogenesis.”

William’s (:04b) account of gametogenesis in Dictyota is the

most complete that we have for any thallophyte. The oögonia

and antheridia are cut off from a stalk cell by a mitosis which

presents 16 chromosomes, the number characteristic of the

gametophyte. The contents of the oögonium forms a single

egg and consequently presents no mitotic phenomena. The

antheridium develops over 1500 sperms thus exhibiting a large

number of successive divisions. These all show 16 chromosomes

and the mitoses are typical, not differing in any essential from

the division in the stalk cell. The entire absence of mitoses in

the oógonium and the great number in the antheridium are

striking facts which show that no especial significance can be

attached to nuclear divisions within sexual organs of this type.

There is no place for reduction phenomena within these sexual

organs and none precede their development.

These studies of Williams and Wolfe justify us in expecting .

that other thallophytes will support their discoveries that the

product of the sexual act will have a fusion nucleus with double

the number of chromosomes present in the sexual plant (game-

tophyte) and that reduction phenomena may be expected to fol-

low the sexual act and not precede it as in animals. In such

thallophytes as have no sporophyte generation we may suppose,

as Strasburger (94a) suggested, that the number of chromo-

No. 463.] STUDIES ON PLANT CELL.— VI. 459

somes is reduced with the germination of the sexually formed

cell so that the protoplasm returns at once to the potentialities

of the gametophyte. It is quite possible that the four zoó-

spores produced from the oóspore of (Edogonium and the four

nuclei found in the germinating zygospores of the desmids and

Spirogyra may indicate divisions concerned with reduction

phenomena similar to those in the tetraspore mother-cells of

Dictyota (which may also be expected in the tetraspore mother-

cell of the red algae) and in the spore mother-cell of the higher

plants. !

For these reasons we seem to be justified in taking a critical

attitude towards the accounts of chromosome reduction at game-

togenesis among the thallophytes. The logic of the situation

would lead us to expect that every sexual act gives a doubling

of the chromosomes and an impulse towards the development

of a sporophyte phase in plants which must be worked off before

the protoplasm is in condition to reproduce the parent gameto-

phyte. Reduction phenomena should follow then every sexual

act. If it takes place immediately with the germination of the

sexually formed cell there is of course no sporophyte generation.

Because the conception of the sporophyte generation with reduc-

tion of the chromosomes at sporogenesis is so clearly established

in higher groups, those investigators who claim reduction phe-

nomena at gametogenesis must expect their views to be severely

scrutinized and accept the responsibility of presenting very clear

and convincing proof of their conclusions. The author does

not think that this evidence is supplied in satisfactory form by

any investigation so far.

2. FERTILIZATION.

n IV of these “Studies” we described the most

important phenomena of fertilization under the caption “ Sexual

Cell Unions and Nuclear Fusions." It will not be necessary to

discuss the facts of the phenomena in detail again. This account

will take up the more theoretical aspects of the events of ferti-

lization and their relation to other critical periods of ontogeny.

Plants are in complete agreement with animals in the follow-

In Sectio

460 THE AMERICAN NATURALIST. (VoL. XXXIX.

ing chief events and principles of fertilization. Thus Van

Beneden's conclusion of 1883 that sexual nuclei are equivalent

in their chromatin content at the time of fusion irrespective of

differences in size is admirably borne out by Miss Ferguson's

(: 04) studies on the pine. In this form as in the gymnosperms

generally the male nucleus is much smaller than the female and

comes to lie in a depression in the latter before the actual fusion

takes place. Afterthe fusion the paternal and maternal chromo-

somes are found in two groups side by side preparatory to the

first cleavage mitosis and are indistinguishable except for their

position ; the chromatin of the two sexes is equal in amount as

far as can be seen. Then the observations of the Hertwig

brothers, in 1887, and Boveri, in 1889 and 1895, that the sperm

nucleus could enter and cause the development of denucleated

eggs or their fragments thus taking the part of a female nucleus

in parthenogenesis, were established for plants by Winkler's

(: OI) experiments on Cystoseira. Winkler was able to divide

the egg of this brown alga into a nucleated and a non-nucleated

portion and he found that sperms entered the non-nucleated

parts and caused them to develop sporelings side by side with the

fertilized nucleated portions. The sporelings from the non-nucle-

ated fragments, controlled by the sperm nuclei alone, developed

about half as rapidly as those from the originally nucleated por-

tions which of course were dominated by sexually formed fusion

nuclei, but the two sets of sporelings were alike in form as far as

they were grown. Only with respect to Boveri's celebrated

theory that the sperm brings to the egg in the centrosome the

mechanism of cell division, do plants fail to support the conclu-

sions of certain zoölogists with respect to the most important

events of fertilization. This point upon which zoólogists are

not in full accord will be discussed later. There is general

agreement in the view that the male nucleus of plants supplies

chromosomes equal in number and equivalent quantitatively to

the female, and general accord in the conclusions that the chro-

mosomes by their individuality, apparent permanence of struc-

ture, and fixed behavior must be bearers of hereditary characters.

Evidence from the most recent investigations upon favorable

forms of both animals and plants indicates that the chromosomes

No. 463.] STUDIES ON PLANT CELL.— VI. 461

from both gametes maintain their independence and never fuse

at the immediate time of fertilization. We have reason to

assume, chiefly from zoólogical studies, that the paternal and

maternal chromosomes of plants remain independent throughout

the entire sporophyte generation and that no fusion takes place

until the period of chromosome reduction at sporogenesis. If

no sporophyte generation is present we should expect the fusion

and reduction of the chromosomes to occur after the sexually

formed cell had passed through a period of rest (for all reduction

phenomena seem to require considerable time) unless there be

actually such reduction during gametogenesis in the thallophytes

as reported for Fucus and Saprolegnia. The morphology of the

chromosomes is probably unchanged by the immediate act of

fertilization. The fusion nucleus simply contains double the

number of chromosomes present in each gamete nucleus which

increases by so much the metabolic possibilities which lie in

these structures.

Besides chromatin the sperm brings into the egg a certain

amount of cytoplasm. Some of this may be the substance of

the blepharoplast or other kinoplasm associated with the nucleus

but there is often besides considerable granular trophoplasm,

sometimes with inclusions of starch and other food substances,

and the male gamete of certain thallophytes contains a chroma-

tophore. There is no reason to suppose that development

especially characteristic of fertilization, the sporophyte genera-

tion, has any relation to this trophoplasm with its food inclusions,

excepting as' it may stimulate growth which is to be expected

whenever organic food material is introduced into protoplasm.

But we can hardly believe that the formative elements or the

rudiments of further development especially those of a sporo-

phytic character lie in this region of the protoplasm. They

must be sought in the nuclei and in the only stable elements of

the nuclei, the chromosomes.

It has been held at times by botanists, following the lead of

certain zoölogists, that the sperm or sperm nucleus introduced a

centrosome into the egg which organized the first cleavage-

spindle and thereby played a necessary part in starting cell

division. Such a centrosome would naturally be sought in the

462 THE AMERICAN NATURALIST. [Vor. XXXIX.

blepharoplast which is clearly analogous to the middle piece of

the animal spermatozoón. We have no evidence that such events

ever take place in the eggs of plants. On the contrary we know

that the first cleavage-spindle in the eggs of spermatophytes

develops without centrosomes from a mesh of fibrille. Also

the blepharoplasts of the gymnosperms Cycas, Zamia, and Ginkgo

remain in the cytoplasm at a distance from the fusion nucleus

and Shaw's account of the fern, Onoclea, indicates that similar

conditions obtain there. We know less about the history of the

blepharoplasts within the egg of thallophytes where the first

cleavage-spindle frequently has very handsome centrospheres

and asters (e. g., Fucus and Dictyota). Strasburger (97a)

pointed out that one of the asters of the first cleavage-spindle

in Fucus arose near the point where the male nucleus united

with the female. However, Farmer and Williams (98) believe

that centrospheres of the first cleavage-spindle in Fucus are

formed de novo and Williams (:04b) came to the same conclu-

sion for Dictyota. There are some very interesting features in

the comparative study that Williams (:04b) has made on the

and parthenogenetic eggs of Dictyota. The spindle in the par-

thenogenetic egg is multipolar and develops from an intranuclear

kinoplasmic mesh and there are no centrospheres. But in the

It seems then probable that the only structures of the sperm

that preserve their morphological entity in the fertilized eggs of

plants are the chromosomes. Whatever may be the relation of

the blepharoplast and other cytoplasmic structures as stimuli to

the development of the egg they cannot be regarded as fixed

factors in the problem of heredity. It is very probable that

they introduce valuable food material, perhaps important fer-

No. 463.] STUDIES ON PLANT CELL.— V1. 463

ments, substances of great service, although possibly not abso-

lutely necessary to the successive metabolic processes which

characterize growth and development. But the fact remains

that we have in the chromosomes the only new morphological

elements. And the progress of research seems ever to

strengthen the general view that in the chromosomes are

contained the directive rudiments of development and that

they are the bearers of hereditary principles. Nuclear studies

on apogamous forms will certainly prove of great interest in this

connection. We have reason to expect some very important

results from thorough cell studies on apogamy and apospory.

The best developed theory of fertilization in plants is that of

Strasburger and a statement of his views should precede any

comments of other authors. Strasburger has written much on

the phenomena of fertilization ; important considerations may be

found in his papers of '94a, b, '97c, : 00a, b, : O1, and :04a.

Strasburger points out that the protoplasm of the egg is pre-

dominately trophoplasmic in character because of the propor-

tionately very large amount of cytoplasm with granular inclusions

that are evidently food material or the products of metabolism.

On the other hand the cytoplasm of the sperm contains rela-

tively little trophoplasm and much kinoplasm, especially when

the sperm is a ciliated cell with a large blepharoplast. As

Strasburger conceives kinoplasm to be the active substance of

spindle formation, he concludes.that the sperm might bring to

the well nourished egg, rich in trophoplasm, the substance neces-

sary to start the mechanism of mitosis. In its broad aspects

this view is very similar to the celebrated theory of Boveri, 1887,

that the spermatozoón supplied the animal egg with the centro-

some which is conceived as necessary to start mitotic processes

and that the egg is powerless to divide before fertilization

because it lacks such a structure.

Another feature of Strasburger's views (advanced in his paper

of :oob) appears to have grown out of the discovery of the so

called “double fertilization ” in the embryo-sac and other nuclear

fusions whose sexual significance is not clear, together with the

phenomena of parthenogenesis as produced experimentally in

many studies of recent years. Strasburger considers that two

464 THE AMERICAN NATURALIST. [VoL. XXXIX.

processes are involved in the sexual act. The first, termed

"vegetative fertilization," is simply the stimulus to growth

which results from the fusion of two nuclei or other masses of

protoplasm. The second, called “generative fertilization," in-

volves deeper factors than those of mere growth stimulus.

These lie in the union of germ plasm of diverse parentage with

the mingling of hereditary racial characters and individual varia-

tions and the establishment of a new organism which may have

possibilities of development quite different from the parent form.

The effects of ‘vegetative fertilization " may be imparted to

protoplasm artificially by chemical and physical stimuli as has

been done in the numerous experiments of Klebs and Loeb

on the conditions which induce parthenogenetic development.

“ Generative fertilization" has a phylogenetic significance and a

background which is entirely apart from the mere vegetative

processes of cell growth and division.

It is apparent that Strasburger's theory is open to the same

line of criticism that has been brought against the universal

application of Boveri's hypothesis that the spermatozoón brings

to the egg the agent of cell division as a centrosome. The

investigations of several zoölogists indicate that one or both of

the centrosomes in the first cleavage-spindle may be derived

from the egg or may be formed de novo (see Wilson, : oo, pp.

196, 208). The kinoplasm of the plant sperm, whether in the

form of a blepharoplast or as an ill defined accompaniment of

the sperm nucleus has not been shown to take part in the forma-

tion of the first cleavage spindle. There is no evidence that the

blepharoplast retains its organic entity in the egg to pass over

into à centrosome or centrosphere. Of course the kinoplasm

which lies immediately without the nuclear membrane of the

investing layer around the fusion nucleus. It is reasonable to

Suppose that the mixing of these masses of kinoplasm with the

No. 463.] STUDIES ON PLANT CELL— VI. 465

fusion of the gamete nuclei would give material for a larger and

more highly differentiated nuclear figure in the first cleavage of

the egg. :

Williams’ (:04b) observations and conclusions on Dictyota

are especially intefesting in this connection for he shows that the

first cleavage-spindles in the parthenogenetic eggs are intranu-

clear and multipolar, showing no dominant kinoplasmic centers

while the fertilized eggs form each a well differentiated centro-

sphere with radiations, exterior to the nuclear membrane, which

clearly guides the whole process of spindle formation. Williams

does not hold that this centrosphere comes as an organized struc-

ture from either sperm or egg but is developed de novo by the

fusion nucleus as the result of the general stimulus of fertiliza-

tion. The evidence, then, furnished by studies on fertilization

in plants, indicates that the chromosomes alone maintain mor-

phological independence throughout the process of fertilization

and that the kinoplasmic (archoplasmic) elements play no part iri

the phenomena as fixed morphological structures but simply con-

tribute their substance to the general union of cytoplasm with

cytoplasm, and that any specialized kinoplasmic structures of the

first cleavage spindle are formed de novo. While it is true that

the sperm brings to the egg much kinoplasm it may well be

questioned whether such kinoplasm is a necessary factor in the

formation of the first cleavage-spindle. It seems more proba-

ble that the development of achromatic structures in the first

mitosis following fertilization is due rather to the general stimu-

lus of cell and nuclear fusion than to particular structures sup-

plied by either sperm or egg.

The second phase of Strasburger's theory of fertilization con-

cerns a separation of the two processes in the sexual act: (1)

the mere growth stimulus, * vegetative fertilization," that may

be expected with the union of any two masses of protoplasm,

and (2) the clearly defined sexual phenomena, ‘t generative fer-

tilization,” which lies in the union of germ plasm of different

parentage and diverse potentialities and which leads to the

inheritance of these characteristics. It seems clear that the two

processes are really present and can be clearly distinguished.

But it may be strongly questioned whether the factors charac-

466 THE AMERICAN NATURALIST. (VoL. XXXIX.

terizing the first (vegetative fertilization) should really be con-

sidered a part of the sexual act. Strasburger regards the proc-

esses of “ generative fertilization ” as essential to the sexual act.

The growth stimulus “vegetative fertilization ” is always to be

expected as an accompaniment of fertilization. It may be given

to cells in other ways than by the sexual act and is found in cell

and nuclear fusions which for phylogenetic reasons are plainly

not sexual.

The experimental work of recent years on the conditions

determining artificial parthenogenesis have done much to define

the sorts of factors which stimulate growth and division of sexual

cells when the process of fertilization is suppressed. Klebs for

plants and Loeb for animals have been foremost in these studies

and they have shown that what seem to be very minor changes

in the environment of the sexual cell may suffice to give a gamete

the power of immediate development without fertilization. Thus

the egg of the sea urchin will develop parthenogenetically to an

advanced stage when placed for a short time in sea water contain-

ing magnesium chloride and then brought back to normal sea

water. Nathansohn (:00) found that a small proportion (about

7 %) of the eggs of Marsilia vestita would germinate partheno-

genetically when the megaspores were cultivated for 24 hours at

the rather high temperature of 35? C. and then left to continue

their development at 27° C. There are then a number of fac-

tors such as varying osmotic pressure, temperature, and in some

cases chemical reagents which may induce gametes to further

development without the usual sexual processes. These reac-

tions seem to be of a similar character to the processes in that

phase of sexual reproduction termed * vegetative fertilization "

by Strasburger. They give the stimulus to growth but without

that essential feature of sexuality, the mingling of germ plasm of

different parentage which distinguishes the processes of “ gener-

ative fertilization.”

It seems to the author, for the sake of clearness, that we are

trying to include too much under the term fertilization. If the

features of “vegetative fertilization," 7. e., the growth stimulus,

can be introduced experimentally as in artificial parthenogenesis

then they cease to be fundamental qualities of the sexual act.

No. 463.] STUDIES ON PLANT CELL.— VI. 467

They are accompaniments of sexual processes which may always

be expected but nevertheless are not the essential characteris-

tics. The essence of the sexual act (fertilization) is the union of

germ plasm with such possibilities of new developments as come

from the inheritance of mixed characters from two lines of ances-

try. And the more diverse and complex are the characters of

the parents the more conspicuous are the essential features of

the sexual act. Among lowly organisms and in simpler types of

sexual processes the growth stimulus becomes exaggerated in

our attention because the features of heredity are not so promi-

nent as in the higher forms. But in the higher groups the

varied characters of offspring express clearly the subtle factors

concerned with the mingling of diverse germ plasm in the proc-

ess of fertilization and the growth stimulus recedes into the

background.

For these reasons it seems to me that the term fertilization

should only be used for the mingling of germ plasm with the

possibilities of new combinations in the potentialities of the

resulting sexually formed cell and that the growth stimulus should

be treated as an accompaniment but quite apart from the essen-

tials of the sexual act. And for these reasons I was careful to

include in Section IV under the caption * Sexual Cell Unions

and Nuclear Fusions" only illustrations in which the sexual

nature of the phenomena was clearly shown by applying a mor-

phological or phylogenetic test to the elements concerned in the

process of cell fusion. The phylogenetic test seems to me the

only sure way of determining the sexual nature of the members

of a cell fusion and there are very few cases in which there can

be any hesitation in deciding whether or not such elements are

morphologically gametes.

I included under “Asexual Cell Unions and Nuclear Fusions”

in Section IV a number of cases in which the sexual nature of

the act is under dispute for the reason that none of these satisfy

the phylogenetic test. It is perfectly clear that the growth stim-

ulus is a conspicuous feature of these cell and nuclear fusions.

and that in this feature they resemble sexual processes but this

mind, make them acts of fertilization or the

does not, to my —

nion of sporidia in the

equivalent of sexual processes. The u

468 THE AMERICAN NATURALIST. [Vov. XXXIX.

smuts and of yeast cells, the fusion of nuclei in the teleutospore

and basidium and in the apogamous development of ferns, the

double fusion of polar nuclei and multiple nuclear fusions in the

embryo-sac (Corydalis) illustrate phenomena which I cannot

regard as sexual eyen though they have in them elements asso-

ciated with sexual processes and in certain cases may be substi-

tutes for a former sexual act. In none of these instances can

we be positive that the nuclei concerned are morphologically and

phylogenetically gamete nuclei. This point was discussed in

some detail in Section IV. It seems to me that Blackman’s

(:04a, p. 353) conception of the cell fusions preceding the æci-

dium in Phragmidium as “reduced forms of ordinary fertilization "

or Farmer's (:03) explanation of apogamy in the fern “as a kind

of irregular fertilization" leads to a confusion of a substitute

process with a true sexual act. The substitute processes have

their true place as phenomena of apogamy. They can, however,

only have a sexual significance if they represent the origin of a

new set of gametes in the organism, a proposition which is not

likely to be maintained by anyone.

3. SPOROGENESIS.

We are employing the term sporogenesis, as must have been

apparent in preceding divisions of this paper, to designate a

characteristic and highly specialized type of spore formation that

is universal in all plants above the thallophytes. The process

always terminates the sporophyte phase in ontogeny of these

higher plants, and is especially distinguished as the period of

chromosome reduction in the life history. The cell activities of

sporogenesis are therefore of particular interest, and, since spore

mother-cells are generally large and their nuclear and cytoplasmic

structure especially clearly differentiated, we have perhaps ob-

tained more knowledge of mitotic phenomena from the study of

these elements than of any other tissues of the plant body.

t The reduction phenomena of sporogenesis have been estab-

lished in some forms of the thallophytes, certainly in the tetra-

spore mother-cell of Dictyota (Williams, :04a). There are also

reasons for suspecting that the oóspore of CEdogonium and the

No. 463.) STUDIES ON PLANT CELL.— VI. 469

zygospores of Conjugales on germinating present similar events.

The teleutospore and basidium are probably also the seat of

chromatin reduction (Blackman, :04b) in the formation of

spores either directly or through the promycelium. The ascus

holds a position at the end of a sporophyte phase which suggests

a similar relation in this group of fungi. Chromosome reduction

may also be expected in the tetraspore mother-cell of the Rho-

dophyceze, as in Dictyota, but this subject has never been inves-

tigated. There are occasional red algze in which the tetraspores

are sometimes borne on the same plant with the sexual organs,

conditions which may be difficult to explain on the theory that

the tetrasporic plant is a sporophyte. Thus Spermothamnion

turneri on the American coast frequently bears both procarps

and tetraspores on the same plant, and I have also seen cysto-

carpic plants of Ceramium rubrum some of whose branches con-

tained tetraspores. Lotsy (:04a) also reports similar conditions

in Chylocladia kaliformis. The other extremely varied methods

of spore formation (zoöspores, conidia, etc.) in the thallophytes

do not concern the present discussion: They seem to have no

fixed place in the life history and there is nothing to indicate

any relation to reduction phenomena, although we actually know

nothing about the chromosome history among, these lowly forms.

The importance of sporogenesis as a critical period in the life

history of higher plants became at once apparent with the dis-

covery that fertilization doubled the number of chromosomes in

the nuclei of the sporophyte phase and that the double number

was reduced during sporogenesis. As stated in our account of

gametogenesis, these facts were first established for a number of

spermatophytes by the work of Strasburger ('84, '88, and 94),

Guignard (84, '85, and '91), and Overton (93 a and b). Guig-

nard (’91) presented for Lilium martagon the first complete

account of the number of chromosomes in the life history of a

plant, and his results were also established independently by

Overton ('93 a and b). Then followed confirmatory arestiga

tions among the bryophytes in the work of Farmer ('94, '95 a,

b, c) and in the pteridophytes by Strasburger (94, p. 294) for

Osmunda. Since 1895 the investigations among the spermato-

phytes have so multiplied that we know the number of chromo-

470 THE AMERICAN NATURALIST. (VoL. XXXIX.

somes in sporophyte and gametophyte for more than fifty forms.

This list may be found in Coulter and Chamberlain's recent

text-book, Te Morphology of the Angiosperms, 1903, p. 81.

Farmer's accounts of the number of chromosomes in the Hepaticze

have been confirmed and extended by myself (Davis, '99, : 01a)

and by Moore (:03). The more recent literature, especially as

it concerns the events of spindle formation in the mitoses char-

acteristic of sporogenesis has been treated in our account of the

spore mother-cell (Amer. Nat., vol. 38, p. 725, Oct., 1904).

There are two chief periods in the processes of sporogenesis

as illustrated in all groups above the thallophytes: (1) a growth

period and (2) a period of cell division. In the growth period

the spore mother-cells become differentiated from the general

sporogenous tissues through a great increase in the amount of

protoplasmic material. At some time in this growth period the

nucleus of the spore mother-cell exhibits the phenomenon of

synapsis, a very characteristic event, recognized by the very

much contracted condition of the chromatin network in the

interior of the nucleus. Synapsis is believed to hold fundamental

relations to reduction phenomena as the time when chromosomes

unite with one another in pairs. The period of cell division fol-

lows synapsis and is characterized by two mitoses in the spore

mother-cell, the second following immediately upon the first, and

a segmentation of the protoplasm, sometimes by two successive

divisions, and sometimes by a simultaneous cleavage, into four

spores. The two mitoses present certain peculiarities in the

structure and behavior of their chromosomes which are unlike

the events of typical mitoses. The first is known as the hetero-

typic and the second as the homotypic mitosis. These peculiar-

ities have been recognized for a long time and have furnished

the subject of much investigation and contradictory explanations.

They were briefly described in Section III (Amer. Nat., vol. 38,

P. 740, Oct, 1904) but recent studies of Farmer and Moore

(: 03, : 05) have opened again a discussion which seemed closed

at that time. The details of synapsis and the heterotypic and

homotypic mitoses will be taken up under the caption, ** Reduc-

tion of the Chromosomes.”

Contrary toa statement in Section III of these studies (Amer.

No. 463.) STUDIES ON PLANT CELL — VI. 471

Nat., vol. 38, p. 726, Oct., 1904) there is probably a deep sig-

nificance in the fact that two mitoses are almost universally

present in the spore mother-cell so that four spores are formed.

It is probable that these mitoses are always heterotypic and

homotypic, although this fact has only been clearly established

in comparatively few favorable forms, and that they are indis-

pensable to the mechanism of reduction phenomena. The latest

accounts describe the first mitosis as the separation of the two

portions of a bivalent chromosome, that is of two chromosomes

joined either side by side or end to end, giving it a unique posi-

tion among the mitoses of the life history. According to these

theories the two mitoses of sporogenesis are features of a

remarkable mechanism by which the paternal and maternal

chromatin after its union in synapsis may become distributed in

proportions that can be expressed by mathematical ratios. The

peculiarities of the homotypic mitosis depend on a premature

fission of the daughter chromosomes of the heterotypic division

as will be explained in the next portion of this section. Thus

the four spores are the result of these peculiar mitoses and have

morphological significance. We are even justified in suspecting

that the groups of four spores when found in the thallophytes,

as the tetraspores of Dictyota and the red algze, the four spores

formed on the basidium and promycelium and the four spores of

nuclei present in the germinating oóspore and zygospore of

e Conjugales indicate the presence of reduc-

CEdogonium and th

the number four is so constant.

tion phenomena simply because

Williams (: 04a) for Dictyota and Blackman (: 04b) for types of

the Uredinales have discovered clear cytological evidence of this

reduction phenomenon but we know nothing of the chromosome

history in other types.

We have already referred to the fact (Section III, Amer. Nat.,

vol. 38, p. 743, Oct, 1904), that in the spermatophytes the

two mitoses characteristic of sporogenesis are very close to the

mitoses which differentiate the gamete nuclei. In the male

gametophyte of the Angiosperms there are generally only two

mitoses between the events of sporogenesis and gametogenesis

and in gymnosperms there is a somewhat larger and variable

number. The female gametophyte of the angiosperms usually

472 THE AMERICAN NATURALIST. | (Vor. XXXIX.

presents three mitoses after those of sporogenesis before the

egg nucleus is formed. But in a number of types in the lily

family (e. g., Lilium, Tulipa, Fritillaria, Erythronium, etc.), the

mitoses of sporogenesis are actually included in the embryo-sac

and the very next mitosis, which is typical, differentiates the

egg (see Section III, Amer. Nat., vol. 38, pp. 741-744, Oct.,

1904). This is the furthest point attained in the reduction of

the gametophyte which in such forms actually includes but a

single nuclear division, in its history. But however close the

mitoses of sporogenesis come to those of gametogenesis it is

perfectly clear through the long phylogenetic history in the

lower spermatophytes, pteridophytes, and bryophytes that the

two are morphologically distinct processes and are always sepa-

rate. It is unfortunate that the terms spermatogenesis and

oögenesis should be applied to processes of sporogenesis as has

been done by several authors, for such usage involves a confusion

of two events which phylogeny clearly shows to be different in

origin and to have back of them the diverging history of sporo-

phyte and gametophyte from the times of thallophyte ancestry,

the most remarkable evolutionary history in the plant kingdom.

It is conceivable that some plants may finally reach a stage in

their evolutionary history when all the gametophytic mitoses in

the pollen grain and embryo-sac will be suppressed and the

nuclei resulting from sporogenesis become gamete nuclei. But

it is clear that in such an event the gametophyte phase would be

obliterated and we should have an entirely new type of life

history. There would then be only one organism (derived from

the sporophyte) whose gametes would be formed immediately

with the differentiation of the pollen grain and embryo-sac.

Such an organism would present reduction phenomena with the

differentiation of the gametes and its type of life history would

be identical with that of animals. We should look for such a

reduced life history in groups related to forms in which the

mitoses of sporogensis are included in the embryo-sac and the

gametophyte phase is represented by a single nuclear division

(c. g, Lilium, Tulipa, Fritillaria, Erythronium, etc.. Search

among some of the most highly specialized Monocotyledonze may

actually reveal examples of the complete suppression of the

female gametophyte. .

No. 463.] STUDIES ON PLANT CELL— VI. 473

The speculative possibilities of a suppression of a sexual gen-

eration and the assumption of sexuality by an asexual phase

were clearly in the mind of Strasburger when he suggested

('94b, p. 852) the possibility that the two mitoses characteristic

of oógenesis and spermatogenesis in animals might signify the

remains of a former sexual generation now entirely suppressed

in the Metazoa. This suggestion was based on the striking

similarity of the events of sporogenesis in plants to those of

gametogenesis in animals and on the history of sporogenesis as

shown in plant phylogeny. This history is remarkably clear and

there can be no question but that the phenomena of sporogenesis

have developed as the result of sexual processes and are always

associated with an asexual generation (sporophyte). It is also

clear that the ancestral primitive sexual generation (gametophyte)

has steadily degenerated until now it is almost lost in such

embryo-sacs as include the two mitoses of sporogenesis within

their history. If the sexual generation should become entirely

lost the life history of a higher plant would present the same

features with respect to the period of chromosome reduction as

that of an animal: there would be but one organism, the homo-

logue of the sporophyte which would produce gamete nuclei with

reduction phenomena previous to gametogenesis just as in ani-

mals. Several authors have expressed views similar to Stras-

burger's suggestion ('94b, p. 852) or carried the speculation even

farther than he. Beard ('95a, p. 444) along these lines of argu-

ment combined with conclusions from Bower's (87) studies on

apospory, announced a belief that “ Metazoan development s

really bound up with an antithetic alternation of generations,

Lotsy (:05, p. 117) expresses unequivocally the view that the

animal body represents an asexual phase (2x generation) and that

the sexual phase (x generation) is confined to the sexual cells.

Chamberlain (:05) simultaneously with Lotsy and in much

greater detail presents a comparison of the phenomena of sporo-

genesis in plants with gametogenesis in animals tracing the

resemblance in the events of chromosome reduction step by step

and states his belief that “animals exhibit an alternation of gen-

eration comparable with the alternation so well known in plants.

This is not the place to consider this theory in detail from a

474 THE AMERICAN NATURALIST. (VoL. XXXIX.

zoölogical standpoint since it bears only indirectly upon the

material of these papers. Zoölogists have, however, discussed

critically Strasburger's suggestions (see Wilson, :00, p. 275,

and Häcker, '98, p. 101). The difficulties of accepting this

view of a possible antzthetic alternation of generations in animals

seem insurmountable. In the first place there is not the

slightest evidence of antithetic alternation of generations in the

Metazoa or for that matter anywhere in the animal kingdom.

The examples of alternation of generations which the zoölogists

present among the Ceelenterates are all illustrations of omolo-

gous generations derived from buds. There is no indication of

spore formation comparable to the process in the higher plants,

so far as I am able to judge, in any group of animals. And also

there seems to be accumulating evidence of reduction phenomena

previous to the development of sexual cells in the Protozoa

which is essentially of the same character as in the Metazoa

(see Wilson, : 00, pp. 227, 277, and Calkins, :o1, p. 233). It is

very interesting and remarkable that reduction phenomena

should show the same order of events in animals and plants and

the facts should be clearly recognized. But I cannot follow

those botanists who carry over to the animal kingdom the

phylogenetic conclusions which are so clear in plants. The

remarkable agreement of the events of sporogenesis in plants

with gametogenesis in animals appears to me likely to prove

only another illustration of similar biological phenomena which

have evolved independently of one another, an illustration com-

parable with the independent origin of sex, of heterospory, and

probably even of the sporophyte generation itself (involving the

processes of sporogenesis) in various groups of the plant king-

dom. i

We have considered this comparison of reduction phenomena

in plants with animals chiefiy to emphasize the clear cut mor-

phology of the process as understood by the botanist. It does

not matter how close the events of sporogenesis may come to

those of gametogenesis in the higher angiosperms, the whole

background of plant phylogeny, which is wonderfully clear as a

whole, shows that reduction phenomena are the product of the.

asexual generation. It represents, as Strasburger has so well

No. 463.] STUDIES ON PLANT CELL.— VI. 475

expressed it ('94a, p. 288), a return on the part of the plant

organism in each life history to the condition of an ancestral sex-

ual generation (gametophyte). Reduction phenomena in them-

selves are not the result of a gradual evolution, whatever may

be the complicated history of the sporophyte generation, for

they consist always in the sudden reappearance of the primitive

number of chromosomes, characteristic of the generation in

which sex arose (gametophyte). The cause of reduction phe-

nomena is phylogenetic. The interval that may separate this

phenomenon from the responsible sexual act varies immensely in

the plant kingdom according to the evolution of the groups con-

cerned. But the suddenness of the appearance of sporogenesis

tells in every case the same story of an immediate and total

change in the potentialities of the protoplasm in the spore

mother-cell, a change which can only be understood as a phylo-

genetic process deeply seated in the race.

When the events of sporogenesis in plants are considered as

processes of spermatogenesis or oógenesis we disregard the most

remarkable historic outlines that plant phylogeny can present,

to the confusion of clear thought. Botanical science may well

be proud of its achievement in outlining with such exactness the

relations that the critical periods of gametogenesis, fertilization,

. and sporogenesis bear to reduction phenomena and too great

stress can hardly be laid upon the importance of the results.

4. REDUCTION OF THE CHROMOSOMES.

There are perhaps no activities of the cell which have been

the subject of more investigation and discussion than those of

chromosome reduction in animals and plants. The reasons are

clear. The events of gametogenesis in animals and of sporogen-

esis in plants have the deepest significance for an understanding

of the organization of protoplasm because these are periods when

great changes are made evident in the structure of e cells con-

cerned and at the same time in their potentialities. We are

forced to conclude that some of the structural changes at least

are the cause of the new potentialities and the attempt to estab-

lish the cause and effect has been one of the most fruitful and

476 THE AMERICAN NATURALIST. . (VoL. XXXIX.

interesting subjects of cell research. Reduction phenomena also

have a deep phylogenetic significance whose history in plants at

least can be traced with a remarkable degree of exactness.

We are confident that sporogenesis in plants signifies the sud-

den return of the organism to the condition of an ancestral

sexual generation with the reappearance of a primitive number

of chromosomes. The short time consumed in the process and

the details and precision of the cell activities show that we are

dealing with phenomena whose complicated mechanism can only

find explanation in a long phylogenetic history. In the study of

reduction phenomena and fertilization we have reached the con-

clusion that the chromosomes are intimately concerned with the

transfer of hereditary qualities and are probably the chief or

even the sole bearers of these characters. And thus we enter

upon some of the most far reaching problems of biology, those

of heredity, hybridization, and the basis for the remarkable

ratios of inherited characters which Mendel first clearly set

forth.

It seems quite certain for both animals and plants that numer-

ical reduction of the chromosomes takes place through an asso-

ciation of the paternal and maternal chromosomes in pairs to

torm the reduced number of bivalent chromosomes (dyads). We

have presented in Section IV (Sexual Cell Unions and Nuclear |

Fusions ") the evidence which indicates that paternal and maternal

chromosomes do not unite at the immediate time of nuclear

fusion in fertilization. On the contrary, in all higher animals

and plants the paternal and maternal chromosomes are believed

to remain separate throughout the long series of cell divisions in

the new generation up to the time of ‘sporogenesis in plants and

gametogenesis in animals, both events being characterized by

reduction phenomena. The fusion of the chromosomes takes

place in the growth period which differentiates the spore mother-

cell in plants from the archesporium or the primary gametocyte

in animals from.the preceding gametogenous tissue. The growth

period is one of general protoplasmic accumulation and increase

in the chromatin content of the nucleus, and is especially char-

acterized by that peculiar activity in the nucleus termed synap-

sis. Evidence is accumulating that synapsis is the characteristic

No. 463] STUDIES ON PLANT CELL.— VI. | 477

feature of that period when the number of chromosomes is

reduced by half.

Synapsis is followed very shortly by the two mitoses charac-

teristic of sporogenesis. These nuclear divisions have given

rise to a lengthy literature in which well known investigators

have shifted their positions more than once. The discussions

have centered on the methods of fission and distribution of the

reduced number of bivalent chromosomes which appear in the

first mitosis following synapsis. Assuming that the chromatin

is organized into smaller units, represented by the chromatin

granules (chromomeres, Fol, 1891), which compose the chromo-

somes, it is at once apparent that these üner elements may

become variously distributed according to the structure of the

bivalent chromosomes and the character of the mitoses of sporo-

genesis. Each fusion bivalent chromosome is composed of two

chromosomes joined (1) end to:end or (2) side by side or. (3) it

is possible that the chromatin is intricately mixed in the struc-

ture. With respect to the mitoses a transverse division of the

fusion chromosomes might be expected to give a very different

proportionate arrangement of the maternal and paternal chroma-

tin from longitudinal divisions. Should the chromatin granules

differ qualitatively from one another then different parts of a

chromosome might be expected to have different characteristics

which would be distributed by the mitoses of sporogenesis in

various proportions or ratios.

It has long been known that the mitoses of sporogenesis pre-

sent peculiarities in the mode of division and arrangement of

the chromosomes at the nuclear plate which make them unlike

the typical mitoses of cell division. These peculiarities have

led to the designation of the first mitosis as heterotypic and the

second as homotypic, terms which are now applied by both bot-

anists and zoölogists although we have now a much more

extended knowledge of each type than when Flemming first

proposed the classification in 1887. We described fhe charac-

ters of the heterotypic and homotypic mitoses in Section III,

“ The Spore Mother-cell” (Amer. Nat., vol. 38, p. 740, Oct.,

1904), and will presently treat them further since some papers

of the past year have opened again a discussion which seemed

478 THE AMERICAN NATURALIST. (VoL. XXXIX.

closed a few months ago. The chief points of issue in dis-

cussions of reduction phenomena have centered around the sig-

nificance of the heterotypic and homotypic mitoses. A typical

mitosis is believed to present merely a quantitative division of

each chromosome into two halves equivalent in their potentiali-

ties. The evidence for this view lies in the longitudinal fission

by which each chromatin granule on the spirem is supposed to

divide and contribute half of its substance to each daughter

chromosome. Can there be a qualitative division of a chromo-

some by which one of the parts differs in character from the

other, and are there such divisions at the time of sporogenesis

in. plants and gametogenesis in animals when reduction phenom-

ena take place? These have been the chief topics of dispute in

studies of this character for two decades.

The problem then ultimately concerns the structure of the

chromosome and the reason for the constant reappearance of the

number characteristic of the species at the beginning of each

new gametophyte generation. All the prominent theories of

heredity assume that the chromosomes are made up of simpler

elements which stand for characteristics of the race. These

may form various combinations of higher orders and collectively

give the qualities of germ plasm. The simplest members that

can be observed in such a series of structures are the chromatin

granules (chromomeres) which may be found at almost all times

in the nucleus and are especially conspicuous when arranged in

a row on the linin thread of the spirem. Weismann has devel-

oped the most complex conception founded on the above princi-

ples and with the most elaborate terminology. Starting with

the chromatin granule, which he named an id, Weismann

assumed that this element is composed of still smaller structures

called determinants and biophores, the last being the ultimate

living units. Groups of ids make up idants or chromosomes.

The id was conceived to possess all the essential characters of

the specific germ plasm concerned but ids vary somewhat among

themselves, determining thus the individual variations of the

species. Therefore a chromosome or idant will havea varying

structure according to the character and distribution of the ids

which compose it.

No. 463.] STUDIES ON PLANT CELL .— VI. 479

When a chromosome divides longitudinally so that each id

splits in half, the daughter chromosomes are exactly equivalent

and the division of the chromatin is merely quantitative. But

should a chromosome divide transversely then two sets of entire

ids would be separated from one another and the two daughter

chromosomes would differ in proportion as their component ids

varied, 7. e. the division of the chromatin would be qualitative.

These conceptions of the possible structure and mode of division

of chromosomes outline the basis of Weismann's theory of

heredity and will serve to illustrate the general attitude of those

biologists who approach the subject from the standpoint of pre-

formation, although none have cared to formulate such elaborate

assumptions as Weismann. However, there is a general agree-

ment among biologists of this school that elements are present

in the chromatin which do carry hereditary characters and that

the chromatin granule and chromosome have a definite architec-

ture and organic value because of these elements.

Weismann's theory of heredity rests on an interpretation of

the complexities of mitosis presented by Roux in 1883. Roux

assumed that chromatin was not homogeneous in structure

throughout the nucleus, but differed qualitatively in various

regions. The elaborate history of mitosis with the formation

and division of the chromosomes and their distribution through

the mechanism of the spindle seemed inexplicable to Roux

except on the theory that portions of the chromatin represented

specific characteristics which were sorted and distributed accu-

rately according to some system. There could be no need of

such a complicated mechanism as mitosis if the distribution of.

the chromatin was to be merely quantitative for simple direct

nuclear division could perform that operation as effectively as

mitosis. Mitosis then became a device for the qualitative dis-

tribution of chromatin as well as quantitative and the characters

of the daughter cells were determined chiefly by the specific ele-

ments which were given to one or the other. : |

Weismann siezed upon Roux’s suggestion of a possible quali-

tative distribution of chromatin in mitosis and this assumption

became a very important feature of his theory of heredity.

Weismann postulated two methods of mitosis. By the first the

450 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

chromosomes are assumed to split longitudinally into equivalent

halves, which are the facts in all vegetative or somatic mitoses

so far as is known, and the chromatin is distributed quantita-

tively. By the second method chromosomes were conceived to

split transversely so that one half is carried to each daughter

nucleus, and if the two ends of a chromosome differed in the

character of their fundamental elements (ids and determinants)

the chromatin would be distributed qualitatively. Weismann

prophesied in 1887 that this second type of nuclear division

(qualitative mitosis) would be found and ever since investigators

have steadily searched for a transverse division of the chromo-

somes. They have been reported in connection with the mitoses

of chromosome reduction both for animals and plants and the

history of these investigations forms an important part of the

subject of reduction phenomena. But the present interpretation

of these transverse divisions involves the consideration of factors

that were unknown to Weismann and are very different from the

significance assigned by him. The effect of Weismann's specu-

lations, as a stimulus to investigations in these lines can, how-

ever, hardly be overestimated.

Botanical literature dealing with the two mitoses of sporogene-

sis presents a confusion of statements respecting the presence

or absence of a transverse division of the chromosomes. Stras-

burger has changed his opinion three times. In his early studies

Strasburger ('9 5) believed that the chromosomes divided longi-

tudinally in both mitoses of sporogenesis. Then, led by studies

of Mottier ('97) he concluded (97b) that the fission of the chro-

mosomes in the second mitosis was transverse. Almost imme-

diately, however, Strasburger and Mottier reverted to the former

opinion that the chromosomes divided longitudinally, a view

which Strasburger maintained in his lengthy considerations of

reduction phenomena in 1900a. Finally in a recent paper

(: 04b) Strasburger gives a very different interpretation of the

EVA Dr the first mitosis (heterotypic), based on the study of

Galtonia, and in general agreement with the most recent conclu-

sions of Farmer and Moore (:03). Farmer ('95b), Farmer and

Moore (95), Miss Sargant ('96, '97), Guignard (’99a), Grégoire

(99). Lloyd (:02), and Mottier have also held that the divisions

No. 463.] STUDIES ON PLANT CELL.— VI. 481

of the chromosomes in the mitoses of sporogenesis were longi-

tudinal with somewhat varying views, however, as to the exact

time when the two divisions take place. On the other hand

Ishikawa ('97), Calkins (°97), Belajeff ('98), and Atkinson (99,

for Trillium) have claimed that the second mitosis presented a

transverse division. Dixon ('95, '96, : 00) and Schaffner (97)

held a position apart from all these investigators, believing, that

the chromosomes of the first mitosis of Lilium resulted from

loops whose free ends became appressed or twisted together

finally separating at the angle of the loop and thus constituting

a transverse division in this first mitosis. These latter observa-

tions accord with the latest conclusions of Farmer and Moore

(:03) and Strasburger (: 04b). Most of this literature is reviewed

in detail in Strasburger's paper of 19008. We shall omit an

historical discussion of this early work for the entire subject is

approached from quite a different standpoint in the series of

papers which have appeared in the past three years (1903-05)

and which give hope of much clearer information on the mitoses

of the spore mother-cell.

The remainder of this treatment of “ Reduction of the Chro-

mosomes” will take up the recent papers and try to show the

drift of the present investigations. These papers had not

appeared when the author described the behavior of chromo-

somes during mitosis in Section II (Amer. Nat., vol. 38, p. 445,

June, 1904) and presented the account of the spore mother-cell

in Section III (Amer. Nat., vol. 38, pp. 726, 740, Oct., 1904).

At that time it seemed probable that Strasburger's conclusions

of 1900 held true for all plants, namely, that the chromosomes

split longitudinally in both mitoses of sporogenesis as well as in

all other mitoses of the life history. Whether these views may

have to be materially changed in the light of the most recent

work is now a matter of dispute. Yet the ground has shifted

so frequently in these perplexing problems that it is hard to feel

sanguine of final conclusions even in the hopeful situation of the

present. I shall take up the events of sprogenes in order,

beginning with the growth period and synapsis and ending with

the two mitoses of the spore mother-cell.

The growth period always extends over a considerable length

482 THE AMERICAN NATURALIST. [Vor. XXXIX.

of time and may occupy even weeks or months. During this

interval the spore mother-cells increase to many times the size

of the archesporial cells from which they were derived. There

is an immense accumulation of protoplasmic material and a cor-

responding increase in the size of the nucleus and its chromatin

content. The growth may be continued in the spores after the

mitoses of sporogenesis, as is characteristically illustrated in the

great increase in the size of the megaspores in the pteridophytes

and certain embryo-sacs. The most striking nuclear activity of

the growth period preceding the mitoses is synapsis. This term

is applied to a very characteristic gathering of the chromatin and

linin material in a compact tangle or ball at one side of the

nucleus and usually near the nucleolus. Nuclei are sometimes

in a state of synapsis for several days or perhaps weeks as is

shown by the frequency of the stage in sporogenesis. Thus

during the entire period of sporogenesis in Anthoceros from the

inception of the spore mother-cell to the final differentiation of

the spores (which must take many days) the period of synapsis

occupies from one eighth to one sixth of the entire time (Davis,

'99, p. 104). Synapsis has proved to bea very difficult subject

for study and few investigators have made detailed observations

upon its events. Some have claimed that synapsis is an artifact

due either to poor fixation or to a particularly sensitive condi-

ton of the cell nucleus by which the chromatin was especially

susceptible to shrinkage but it seems certain now that the

phenomenon is entirely normal. Miss Sargant (97, p. 195) has

observed synapsis in the living pollen mother-cell of Lilium

martagon. Anthoceros presents a particularly favorable subject

for the study of the effects of fixing fluids on spore mother-cells

because one may present all sta

: : ges in the same sporophyte to

identical conditions.

which are cccasionally found in cells. Thus Miyake (Annals of

1903) noted the resemblance to synapsis

No. 463.) STUDIES ON PLANT CELL.— VI. 483

of an accumulation of granular material in the nucleus of the

central cell of Picea and other cases might be cited which super-

ficially resemble synapsis but have no fundamental relation to

this peculiar nuclear activity.

Evidence is steadily accumulating that synapsis is a very

important period of sporogenesis. Some authors hold, as will

be described presently, that it is the time when paternal and

maternal chromosomes, which have remained separate through-

out the sporophyte generation, become associated in pairs to

give the reduced number of the gametophyte. This conclusion

makes synapsis the actual period of chromosome reduction and

the two succeeding mitoses become merely distributing divisions

of the newly formed chromosomes. Montgomery (: 01) first

suggested for animals that synapsis involved a union of maternal

and paternal chromosomes in pairs. Other views, however,

regard the reduction of the chromosomes as merely the tempo-

rary union of paternal and maternal elements, end to end, to

form a bivalent chromosome characteristic of the first or hetero-

typic mitosis. According to this view the bivalent chromosomes

divide transversely so that the halves are distributed as whole

chromosomes in the first mitosis.

Two very important papers on reduction phenomena have

appeared this year (1905) both of which were preceded by pre-

liminary publications, that of Farmer and Moore (:03) and

Allen (:04). These two accounts best represent the attitude of

the opposing schools and will be made the chief texts of our

treatment. The fundamental points of difference concern the

events of synapsis and the heterotypic mitosis while there is

complete agreement in the general interpretation of the homo-

typic mitosis. All authors have reached essentially the same

conclusions as regards the purpose and final results of the

reduction divisions but the details of the processes of synapsis and

the prophase of the heterotypic mitosis are described in radically

different ways by various investigators. However, as has been

stated, the views fall into two groups Or schools, one led by

Farmer and Moore with whom Strasburger’s recent paper,

“Ueber Reduktionsteilung " (:04) expresses essential agree-

ment. The other school includes Allen, Rosenberg, and the

484 THE AMERICAN NATURALIST. (Vou. XXXIX.

botanists of the Carnoy Institute, Grégoire and Berghs. ‘To

the writer the conclusions of the second school seem better

founded and we shall present them first. Allen’s last paper

(:05) gives the most complete statement of their interpreta-

tions.

Allen's conclusions (:03, :05) are based on the study of the

pollen mother-cell of Zilium canadense and his account of

synapsis in this form is of great interest for the simplicity of

his explanation of the events of this phenomenon and their sig-

nificance. The nucleus of the young pollen mother-cell follow-

ing the last mitosis in the archesporium and previous to synapsis

contains a network of large irregular masses connected by fibers

of varying thickness. The irregular masses, which probably:

contain both chromatin and linin, are derived from the chromo-

somes of the previous mitosis but these structures cannot be

recognized in the resting nucleus. Nucleoli are present among:

the irregular masses or chromatin knots but are readily dis-

tinguished from them. As the nucleus grows larger the chroma-

tin knots become more widely separated, but synapsis does not

occur until it has reached its full size.

During synapsis the reticulum becomes transformed into a

definite spirem. The fibers connecting the chromatin knots

increase in length and become more uniform in thickness while

the knots become less conspicuous as though their material were

drawn out along the fibers. The fibers of the reticulum are now

seen to arrange themselves in pairs and a general contraction

of the network takes place which is the beginning of synapsis.

Allen believes that this contraction is associated with the approx-

imation of the fibers. The contracting network occupies at first

the center of the nucleus but later moves to the periphery where

the „nucleoli may be found flattened against the membrane.

There is now a continuous spirem in the nucleus, plainly com-

posed of two slender threads lying side by side and probably `

with no free ends. These two threads often run closely parallel,

sometimes loosely twisted about one another, sometimes in con-

i pads e “oes it sometimes rather widely separated.

lens a UM e nue of the thread is not due to a

ependent threads are developed indepen-

No. 463.] STUDIES OF PLANT CELL— VI. | 485

dently out of the reticulum. The two threads gradually fuse so

that in older stages of synapsis the nucleus appears to contain a

single relatively thick spirem which is shorter and more loosely

coiled than in the earlier stages. The minute structure of the

threads of the spirem can be determined by careful staining.

They consist of a series of chromatin granules (chromomeres)

imbedded in the ground substance, linin. As the two threads

fuse the chromomeres generally come together in pairs and unite

to form a single row of large chromomeres which project from

the side of the larger single (fusion) spirem.

The single (fusion) spirem on emerging from synapsis becomes

uniformly distributed throughout the nucleus. There appear to

be no free ends in the much convoluted and looped thread.

Some of the loops become fastened to the periphery of the

nucleus but there is no regularity in the number of loops and no

relation to the number of chromatic segments that are formed

later. While thus evenly distributed the single spirem under-

goes a longitudinal fission which is preceded by the division of

each chromomere. This is the first longitudinal fission of the

spirem which is well known through the descriptions of Guignard,

Grégoire, Strasburger, Mottier, and others. The fission is not

simultaneous throughout the length of the spirem, for some por-

tions remain undivided for some time when contiguous parts are

plainly split. The result is a condition very similar to that pre-

sented just before the fusion of the two systems of threads

during synapsis which produced the single (fusion) spirem. It

seems probable that the threads which become separated are

morphologically the same as those which fused during synapsis

although the union at that period seems complete. The split

spirem remains uniformly distributed throughout the nucleus

exhibiting, however, a tendency to become somewhat massed in

the center of the nuclear cavity leaving fewer loops attached to

the nuclear membrane. |

The split spirem now segments throughout its length into the

reduced number of chromosomes (12) characteristic of the

heterotypic mitosis. The segmentation is not simultaneous, but

the first free ends appear near or at the periphery of the nucleus

where the split spirem breaks apart at the loops. As segmen-

486 THE AMERICAN NATURALIST. | [Vor. XXXIX.

tation proceeds the number of loops becomes fewer and the free

ends more numerous. Allen finds the breaking apart of the

arms of the loops, whose heads are at the periphery of the

nucleus, as described by Schaffner (97) and Farmer and Moore

(105), but cannot accept the interpretation of these latter

authors (to be described presently). Allen’s studies show that

the loops are the points of separation of adjacent split chromo-

somes and not a point where the spirem bends on itself to form

a pair of chromosomes.: The ends of the split chromosomes

when properly stained are seen to be distinct even though they

may be in contact or apparently fused. At the time of the seg-

mentation of the split spirem the two threads are generally

twisted about one another. :

The split chromosomes now shorten and thicken, the num-

ber of twists is reduced and the pairs of elements take on

the many forms characteristic of the heterotypic mitosis and

described as I's, J's, X's, Y's, V's, and O's. These chromo-

somes of the heterotypic mitosis are of course pairs of chromo-

somes, 7. e., bivalent chromosomes or dyads. They are believed

to represent morphologically the full number of sporophytic

chromosomes (24) now associated in pairs forming the reduced

number (12) of bivalent chromosomes. The two threads which

fuse are believed to represent two spirems of maternal and

paternal origin and the chromosomes in the pairs are derived

from different parents.

Shortly after the segmentation of the spirem the sporophytic

chromosomes of each bivalent element or dyad may show evi-

dence of a second longitudinal fission, first recognized by

Grégoire (99), Guignard (99), and Strasburger (: 00) which is

completed during the metaphase of the heterotypic mitosis.

The evidence consists in the appearance of a double row of

granules in each sporophytic chromosome, the result of the

division of the chromomeres. However, these chromomeres

soon become indistinguishable from the linin and the chromo-

somes appear homogeneous from now on.

While the spindle of the heterotypic mitosis is being organ-

ized the position of the sporophytic chromosomes shifts with the

development of the spindle fibers until they are brought to the

No. 463.] STUDIES ON PLANT CELL.— VI. 457

nuclear plate still grouped in pairs as dyads (bivalent chromo-

somes). The details of spindle formation and the heterotypic

mitosis do not concern the present discussion of reduction phe-

nomena. The reduction has occurred with the formation of the

dyads and the mitosis simply distributes the 24 chromosomes

(generally called daughter chromosomes) which are believed to

be the morphological equivalents of the sporophytic chromosomes

that entered the spore mother-cell from the archesporium.

Just before the separation of the sporophytic chromosomes

during metaphase of the heterotypic mitosis a longitudinal fission

appears suddenly in each element extending almost*the whole

length. This is the second longitudinal fission as interpreted

by Grégoire (99), Guignard ('99), Strasburger (100), Mottier

(:03), and others, with whom Allen is in full agreement. It is

of course a premature division of the chromosomes preliminary

to the homotypic mitosis. The second fission is probably com-

pleted at this time but the elements of each pair (formerly

called granddaughter chromosomes) remain clinging together at

one end by a peculiar overlapping of the hooked tips forming

thus a V-shaped pair whose apex is drawn to the poles of the

heterotypic spindle. The daughter nuclei following the hetero-

typic mitosis are not in a true resting condition and the chromo-

somes while forming a spirem show abundant evidence of

independent structure. They emerge from the spirem at the

prophase of the homotypic mitosis as the same morphological

entities (2. e., as V-shaped pairs) and are thus brought to the

nuclear plate from which they are distributed generally as fairly

straight rods to form the nuclei of the pollen grains.

Rosenberg's (:03a, :044, :o4b) studies on the hybrids of

Drosera furnish further evidence that the chromosomes from

different parents fuse in pairs during the prophase of the

heterotypic mitosis. The gametophyte number of een

in Drosera rotundifolia is ten and in D. longifolia twenty and

those of the former species are larger than those of the latter.

The sporophyte number in the hybrid is thirty as would be

expected. At the heterotypic mitosis of sporogenesis, however,

twenty chromosomes appear in the hybrid, half of which are

plainly double structures and consist each of a larger and a

488 THE AMERICAN NATURALIST: | [Vor. XXXIX.

smaller element. During this mitosis the ten double chromo-

somes divide but the single chromosomes remain entire and

either pass to one pole or the other or are left out in the forma-

tion of the daughter nuclei. The explanation of these conditions

must be that ten chromosomes of D. rotundifolia fuse with ten

from D. longifolia leaving ten of the latter without mates.

Rosenberg's last paper (:04b) on Drosera describes in consider-

able detail the union of chromosomes in pairs in both species of

Drosera during sporogenesis. The sporophytic chromosomes

which at first are scattered throughout the nucleus in the early

prophase of the first mitosis come together in pairs and unite so

closely that there is hardly a trace of their dual nature in the

resultant larger bivalent chromosomes, which are of course the

gametophyte number. Rosenberg is very positive that the pairs

of chromosomes are preliminary to a fusion and not the result of

a fission of already reduced segments of a spirem thread.

Rosenberg believes that the two halves of the bivalent chromo-

somes are separated in the first (heterotypic) mitosis and that

each splits lengthwise prematurely during the first mitosis in

preparation for the second. The fused bivalent chromosomes

then appear to divide twice longitudinally but the first division

may be only a separation of the two sporophytic chromosomes

that entered into the fused pair.

We shall consider now the conclusions of Berghs and

Grégoire of the Carnoy Institute, Louvain, whose publications

have appeared practically simultaneously with some of those

which we have just discussed. Berghs has published three

papers (:04a, : 04b, : 05) treating of the early history of sporo-

genesis in Allium, Lilium, and Convallaria, and concludes from

a study of synapsis that the spirem immediately preceding the

heterotypic mitosis arises from the close association, side by

side, of two delicate threads. These threads are organized pre-

vious to and during synapsis and their coming together brings

about that contraction of the chromatic material characteristic

of synapsis. The threads contain sporophytic chromosomes of

the last mitosis in the archesporium. The apparent longitudinal

fission of the spirem which precedes the heterotypic mitosis in

the spore mother-cell is interpreted as being these two threads

No. 463.] STUDIES ON PLANT CELL.— VI. 489

which are believed to have never actually fused during synapsis.

The reduced number of segments derived from the spirem pre-

ceding the heterotypic mitosis are then bivalent chromosomes

composed ‘of pairs of sporophytic chromosomes lying side by

side. The heterotypic mitosis distributes the sporophytic

chromosomes in two sets resulting in a numerical reduction

of their numbers by one half. It will at once be noted that

while Berghs and Allen have independently arrived at similar

conclusions respecting the structure of the chromosomes of the

heterotypic mitosis there are some important differences in the

mode of origin. Allen reports an. actual fusion of the two

threads (paternal and maternal) during synapsis and a later

fission of the spirem previous to the heterotypic mitosis. But

the accounts of both authors have much in common in their

interpretation of the structure of the spirem and chromosomes

of the heterotypic mitosis which is fundamentally different from

the accounts of Farmer and Moore, and Strasburger to be

described later. j

Grégoire (:04) in a general discussion of reduction phenom-

ena confirms the observations of Berghs and takes a very posi-

tive position against the interpretations of Farmer and Moore

and Strasburger. The chief features of his conclusions are in

harmony with the results of Allen. The sporophytic (somatic)

chromosomes are believed to become associated in pairs by the

application of two delicate threads throughout their length during

synapsis. These threads are believed to retain their autonomy

and never actually to fuse although they may come in close con-

tact. Consequently the reduced number of chromosomes are

pairs of sporophytic chromosomes which have retained complete

independence. Allen, on the contrary, reports a complete union

of the two threads involving the fusion of chromomeres in pairs

and a later longitudinal division throughout its length of the

single (fusion) spirem. Grégoire does not regard the heterotypic

mitosis as a true nuclear division but as a special process designed

to effect this numerical separation of the sporophytic chromo-

somes and intercalated between typical mitoses, while Allen

would apparently treat it as a true mitosis and regard the chro-

mosome reduction as effected by the fusion of two sporophytic

spirems during synapsis.

490 THE AMERICAN NATURALIST. | [Vor. XXXIX.

Rosenberg (:05) has recently published a general review of

reduction phenomena based on studies upon Listera, Tanecetum,

Drosera, and Arum, taking a position in essential agreement with

Allen and the investigators of the Carnoy Institute and in

opposition to the theory of Farmer and Moore and Strasburger.

Rosenberg does not quote Allen’s preliminary paper (: 04) which

anticipates his conclusions. He finds that the spirem which

emerges from synapsis is preceded by a condition when the

structure is clearly made up of two threads (spirems) which lie

parallel to one another. These two threads are frequently

joined together, and in places spirally twisted but here and there

they may be seen to be entirely separated from one another.

They finally form the single spirem which follows synapsis and

which divides into the reduced number of chromatic segments.

But the chromatic segments throughout the entire processes are

shown to be double in structure (bivalent chromosomes), 7. e.,

composed of two chromosomes lying very close together side by

side or even united. What appears to be a longitudinal fission

of the chromatic segments of the spirem immediately preceding

the first mitosis is really then a line of union along which the

two independent threads have come together. The phenomenon

of synapsis consists of this close association of two threads

which are themselves simple spirems into a double spirem which

segments into pairs of sporophytic chromosomes each of which

may be regarded as a bivalent chromosome.

Farmer and Moore published a preliminary communication in

1903 which aroused much interest in their theory of chromo-

some reduction. The full account (: 05) has recently appeared.

Their studies are upon Lilium, Osmunda, Psilotum, Aneura,

and the cockroach, Periplaneta. Lilium and Osmunda among

the plants were given chief attention and since the lily was

the type studied by Allen it will serve best to contrast the

conclusions of these two investigators. The accounts of Allen

and Farmer are so fundamentally different as regards the events

of synapsis and the prophase of the heterotypic mitosis that

it seems scarcely possible that both can be right in their

respective material, Lilium candidum, Farmer's type, and Z.

canadense of Allen’s description. Farmer and Moore intro-

No. 463.] STUDIES ON PLANT CELL.— VI. 491

duce the terms ** maiosis” and the * maiotic phase " to cover the

whole series of nuclear changes included in the heterotypic and

homotypic mitoses. The maiotic phase is regarded as similar

in its essential details in both animals and plants but the fact of

its appearance at different points in the life histories precludes

any probability of relationship in such widely divergent lines.

The events of synapsis and the consequent peculiarities of the

heterotypic and homotypic mitoses are considered as intercalated

between the series of typical mitoses in the life history.

Farmer and Moore's conclusions for Lilium candidum may be

briefly summarized as follows. A definite spirem with the

chromatin distributed as granules appears in the young spore

mother-cell before its separation from neighboring elements. A

“first contraction figure" now appears and the spirem thread

becomes densely coiled in the vicinity of the nucleolus, this con-

dition persisting for some time. Then the coils of the spirem

loosen and become distributed about the periphery of the nuclear

cavity, from the point of contraction as a center. A longitudi-

nal fission of the spirem thread then appears, the chromatin

granules dividing so that they come to lie in two parallel rows

on the edge of the split ribbon. The fission is irregular and

open loops appear at places. The spirem then shortens and the

split gradually closes up and becomes very difficult to recognize.

Many of the convolutions of the thread are attached to the

nuclear membrane while the remainder form a tangle in the

interior around the nucleolus which is believed to give up much

of its substance to the chromatic portion of the spirem. Farmer

and Moore then fail to find the double thread and its union dur-

ing synapsis to form a single ( fusion) spirem which is a funda-

mental feature of Allen's account.

There follows then a stage which has been the subject of

much discussion. According to Farmer and Moore the spirem

thread becomes pulled out into V- and U-shaped loops, shown

with especial clearness where the bend of the loop is attached te

the periphery of the nuclear membrane. The arms of the V's

then come to lie parallel and so close together as to give the

structure which is really the result

appearance of a fission in a

two free ends of what was a loop.

of an approximation of the

492 THE AMERICAN NATURALIST. [VoL. XXXIX.

The spirem thread thus breaks up into segments which, how-

ever, lie in pairs represented by the V’s in the reduced (gameto-

phyte) number. The pairs are bivalent chromosomes, each

composed of two sporophytic chromosomes which were arranged

serially on a single spirem thread. The pairs are not always

organized through the approximation of the arms of V-shaped

loops but this is a very characteristic type of structure. The

V's have been interpreted by other authors as the approximation

of portions of the spirem thread (Dixon, '95, '96, : 00) or the

separation of their free ends at the bend of the loop as a trans-

verse division of a reduced number of looped chromosomes in

the heterotypic mitosis (Schaffner, ’97). The two parts of the

bivalent chromosomes (which are pairs of somatic chromosomes)

now become shorter and thicker and all trace of the original

fission of the spirem thread is lost.

The essential features of Farmer and Moore's interpretation

of the prophase of the heterotypic mitosis are, then : (1) a sin-

gle spirem with the sporophytic chromosomes arranged serially,

which splits only once longitudinally, the fission afterward

becoming obliterated when the chromosomes are organized,

and (2) the organization of bivalent chromosomes in the reduced

number largely by the approximation of the free ends of loops

which entails a separation at the bend of the loops of the two

sporophytic chromosomes, giving the appearance of a transverse

division.

The heterotypic mitosis, then, according to Farmer and

Moore involves merely the distribution of the sporophytic chro-

mosomes arranged in pairs (bivalent chromosomes) as univalent

elements to each daughter nucleus. This is of course the gen-

erat conclusion of all recent investigators, the different views

being the result of varying accounts of the method of organiza-

tion of the bivalent chromosomes. During this distribution in

the heterotypic mitosis the split of the original spirem appears

in each univalent element (sporophytic chromosome) and the

halves open throughout the greater part of their length giving

the peculiar V-shaped daughter chromosomes so characteristic

of this mitosis in the lily. The arms of these V's become the

daughter chromosomes of the homotypic mitosis which are thus

No. 463.] STUDIES ON PLANT CELL.— VI. 493

formed prematurely during the heterotypic as was first described

by Grégoire ('99). However, Grégoire and most botanists have

considered the split between the V's as a second longitudinal

fission of the original spirem in the spore mother-cell while

Farmer and Moore regard it as the reappearance of an original

single fission. This view of Grégoire, which has had the sup-

port of Guignard ('99), Strasburger (: 00), and Mottier (:03), is

the theory of a double longitudinal splitting of the chromosomes

previous to the heterotypic mitosis and is also maintained in

Allen’s (: 05) recent paper.

The homotypic mitosis brings about the final separation of the

arms of the V-shaped longitudinally split univalent (sporophytic)

chromosomes of the heterotypic division. The fact that the

arms of these V's finally break apart at the ends does not con-

stitute'a transverse division as has been claimed by some earlier

writers (Ishikawa, '97; Calkins, '97; Belajeff, '98 ; Atkinson,

’99, for Trillium). The peculiarities of the homotypic mitosis

are then due to the premature fission of the univalent chromo-

somes during the heterotypic. As a type of nuclear division the

homotypic mitosis is not fundamentally different from the typi-

cal divisions of other periods of the life history. All recent

authors are in agreement on this interpretation of the events of

the homotypic mitosis.

Gregory (:04) gives an account of sporogenesis for several

leptosporangiate ferns and accepts Farmer and Moore’s explana-

tion of reduction phenomena. He finds the same sort of U-

shaped segments in the reduced number at the heterotypic

division and considers them bivalent chromosomes which divide

transversely so that the original sporophyte chromosomes are

distributed in two sets during this mitosis. The various posi-

tions assumed by the limbs of the U-shaped segments give

appearances very similar to the tetrads described in the hetero-

typic mitosis of animals and which Calkins (97) reported for

Pteris and Adiantum and regarded as resulting from the trans-

verse division of the halves of a longitudinally split chromosome.

Gregory of course cannot accept the conclusions of Calkins.

Williams (:04a) applies the theory of Farmer and Moore

respecting the bivalent character of the chromosomes in the

494 THE AMERICAN NATURALIST. | [Vor. XXXIX.

heterotypic mitosis to his studies on the first division in the

tetraspore mother-cell of Dictyota. But it can hardly be said

that his account offers any material support to the theory.

There is a clear synapsis stage preceding the mitosis in this form

from which a spirem emerges as a beaded thread. This spirem

then becomes split longitudinally and later the chromosomes are

organized and show a longitudinal fission. The form of the

chromosomes at metaphase of the first mitosis is heterotypic, a

ring form being prevalent, and Williams concludes that it is

developed by the bending and closing of the free ends of a

loop. The events of synapsis are not clearly enough known to

make possible a comparison with the accounts of Allen and

Berghs.

We are now ready to take up the latest conclusions of Stras-

burger (:04b) which are closely associated with views expressed

ina recent paper of Lotsy (:04). Lotsy givesa clear state-

ment, illustrated with many diagrams of the various ways in

which sporophytic chromosomes may be conceived to unite in

pairs previous to the first mitosis in the spore mother-cell and

the manner in which the resultant bivalent chromosomes may be

divided and distributed by the two mitoses of sporogenesis.

Lotsy makes parallel comparisons between sporogenesis in plants

and gametogenesis in animals and proposes the term “Gonoto-

konten" (* Nachkommenbildner") for the mother-cells which

inaugurate reduction phenomena. The paper presents no new

observations but discusses the problems of reduction in their

broad aspects. An excellent summary is given by Koenicke

(: 04) |

Strasburger's (: 04b) most recent paper, * Ueber Reduktionstei-

lung," is based chiefly on studies of Galtonia and Tradescantia

and presents an entire change of view from his conclusions of

1900. Galtonia seems to bea very favorable form for study since

the gametophyte number of chromosomes is only six and the

structures are exceptionally clearly differentiated in the spore

mother-cells, which Strasburger calls ** Gonotokonten” after

Lotsy. A single spirem is reported to split longitudinally but

the two daughter threads remain close together. The spirem

then shortens and thickens and becomes distributed in heavy

No. 463.] STUDIES ON PLANT CELL.— VI. 495

loops. It finally divides into six segments which are interpreted

to be six pairs of chromosomes joined end to end. These six

segments are then bivalent chromosomes. The two chromosomes

of each pair (segment) finally come to lie side by side in various

positions by the bending of the original looped segments and the

separation of their two ends in the middle. The halves of the

six bivalent chromosomes (segments) are distributed by the first

mitosis so that there is the effect of a transverse division of six

chromosomes at this time, but really the process is one of the

distribution of twelve chromosomes in two sets of six each.

The longitudinal fission of the spirem thread becomes more con-

spicuous towards the end of the first mitosis so that the twelve

chromosomes become partially split and pass as V’s to the poles

of the first spindle during telophase. This premature division

is preparatory for the second mitosis (homotypic) when the sepa-

ration is finally effected. There is then only one longitudinal

fission of the original spirem in the spore mother-cell and this

prepares the chromosomes for the second mitosis, which differs

only from the typical mitoses in the premature splitting of its

chromosomes. The first mitosis is merely the separation of pairs

of chromosomes joined end to end. Strasburger interprets the

conditions in Tradescantia and Lilium in a similar way believing

that the complications there simply arise from a more involved

looping of the spirem thread. Strasburgers account of Gal-

tonia then supports in all essentials the theory of Farmer and

Moore.

Strasburger in the same paper (04b) gives an account of

synapsis which cannot be brought into harmony with that of

Allen. The chromatin granules are reported to gather during

synapsis into as many centers, which he names “ Gamozentren,"

as will finally form the reduced number of bivalent chromosomes

(six in Galtonia). The “ Gamozentren " then become arranged

and drawn out into the spirem which emerges from synapsis.

The chromatin granules are named “ Gamosomen " and the

bodies formed in the ** Gamozentren " which afterwards become

the bivalent chromosomes of the first mitosis are called ** Zygo-

somen." There are then no organized chromosomes during

synapsis and no place in Strasburger's account for the fusion of

496 THE AMERICAN NATURALIST. | [Vor. XXXIX.

a fully organized paternal and maternal spirem as described by

Allen. The identity of the sporophytic chromosomes becomes

entirely lost, according to Strasburger's explanation of synapsis,

and the chromatin granules (* Gamosomen ") may be variously

distributed in the new set of bivalent chromosomes (** Zygoso-

men"). These * Zygosomen” are a new creation in the cell.

All of the other theories, on the other hand, preserve the mor-

phological entity of the sporophyte chromosomes which are of

course of maternal and paternal origin but allows their distri-

bution in various ratios to one another during the first mitosis of

sporogenesis. The chromosome, however, remains a fixed mor-

phological structure from one generation to another. These

are fundamental differences which have a vital bearing on the

discussion of hybridization, which will follow shortly, since one

of the most important features of the problems concerns the

preservation of the relative purity of the germ plasm.

The chief characteristics of the two theories of reduction

may be summarized as follows : —

(1) According to Allen, Rosenberg, eda and Grégoire,

the phenomenon of synapsis presents a close association of two .

parallel chromatic threads (probably of maternal and paternal

origin) which finally unite to form the spirem that precedes the

heterotypic mitosis. This single (fusion) spirem is then double

in nature and the longitudinal fission which follows, is the sepa-

ration of the two threads that entered into its composition. The

reduced number of chromatic segments of the heterotypic

mitosis are bivalent chromosomes or more precisely pairs of

sporophytic chromosomes derived from the two (maternal and

paternal) threads of the synapsis stage. The heterotypic mito-

sis distributes the sporophytic chromosomes in two sets thus

effecting a numerical reduction by one half. The sporophytic

chromosomes divide prematurely during the heterotypic mitosis

in preparation for the homotypic thus presenting a second longi-

tudinal fission of the segments derived from the single (fusion)

spirem. A special feature of Allen's studies is the fusion of

chromomeres in pairs during the organization of the single

(fusion) spirem and a subsequent splitting of each larger chro-

momere with the longitudinal fission of this structure.

No. 463] STUDIES ON PLANT CELL.— VI. 497

(2) Farmer and Moore, Gregory, Williams, and Strasburger

hold that there is primarily only a single chromatic thread in the

nucleus of the spore mother-cell which is the spirem of synapsis

and the heterotypic mitosis and which most of these authors

believe to be composed of the full number of chromosomes

(sporophytic) joined end to end. This spirem splits longitu-

dinally but the fission is a premature division which prepares the

chromosomes for the homotypic mitosis. The chromosomes of

the heterotypic mitosis are formed from loops of the spirem

which include a pair of sporophytic chromosomes joined end to

end. The members of this pair come to lie side by side by an

approximation of the arms of the loops and a breaking apart at

the head of the structure. This transverse fission of the spirem

is not. of course a transverse division of a chromosome but

merely the separation of a pair of chromosomes joined end to

end. The line between the two arms of the loop marks a region

of contact due to approximation and not a line of fission. The

heterotypic mitosis effects a numerical reduction of the chromo-

somes as in the first view but these chromosomes are formed

on entirely different principles. A single premature fission of

the spirem or its segments prepares the chromosomes for the

' homotypic mitosis.

Comparing the two schools, it may be noted that they both

explain reduction phenomena as à numerical reduction of the

double set of sporophytic chromosomes by a distribution in two

sets. The fission of the chromosomes is always quantitative and

there is no hint in any of the views of a qualitative division in

Weismann's sense. Furthermore, most of the investigators are

firmly convinced of the individuality of the chromosomes which

means that they are convinced as morphological entities persist-

ing from one generation to the next. This is an. important

agreement in relation to theories of heredity and hybridization

which we shall discuss at. another time (see treatment of

“ Hybridization ”). The differences lie in questions of. fact

regarding the organization of these chromosomes in the spore

mother-cell and their behavior during synapsis and at other

periods of prophase in the heterotypic mitosis. There is entire

accord in that the chromosomes of the homotypic mitosis appear

498 |. THE AMERICAN NATURALIST. | [Vor. XXXIX.

during the metaphase of the heterotypic but a fundamental dif-

ference in the accounts of the manner in which these structures

are formed.

In conclusion, we may very briefly note the fact that the

zoólogists are divided into two schools in their accounts of

reduction phenomena, apparently along similar lines to those

of the botanists. Some recent papers (Winiwarter, :00;

Schoenfeld, :01; and the Schreiners, :04) have described the

union of parallel threads (maternal and paternal) during synapsis

to form a single spirem in the rabbit, man, bull, hag-fish, and

shark. Winiwarter and the Schreiners regard a later longitudi-

nal fission of the spirem as a separation of the two threads

which originally entered into the structure. The chromosomes

in the hag-fish (Myxine, the Schreiners, :04) are organized in

pairs side by side and a second longitudinal split appears in

each. The heterotypic mitosis separates the groups in the plane

of the first fission and the two parted chromosomes are divided

by the homotypic. This history is essentially similar to Allen's

account of thelily. On the other hand there is a large body of

observations founded on the investigations of Häcker, vom

Rath, Rückert, Montgomery, and others, indicating that bivalent

chromosomes are formed consisting of somatic chromosomes

joined end to end and that these elements or their derivatives

are distributed either with the heterotypic or homotypic mitosis.

This of course involves a transverse division which is, however,

interpreted as the separation of adjacent chromosomes and not

as a qualitative division in Weismann's sense. The attitude of

the first group is clearly similar to that of Allen, Rosenberg,

Berghs, and Grégoire among the botanists, while that of the

second shows many: points of similarity to the theory of Farmer

and Moore and to Strasburger's last view (:04). There are a

number of accounts of a double longitudinal fission of chromo-

somes especially among the vertebrates, which have not been

harmonized with the last view but may find explanation along

the lines of the more recent investigations.

It is of course conceivable that there are two distinct types of

arrangement of sporophytic and somatic chromosomes in animals

and plants at synapsis during gametogenesis and sporogenesis.

No. 463.] STUDIES ON PLANT CELL-- VI. 499

It is possible that they may be grouped in pairs (bivalent chro-

mosomes) either side by side through two parallel threads

(paternal and maternal spirems) or end to end in a single chro-

matic thread. But it will certainly be interesting if animals and

plants both show variations in these respects and very remark-

able if the same genus, as Lilium, should present contrasting

types of reduction phenomena. And on these points must be

concentrated the future investigations in this field.

While we are making progress in our understanding of the

behavior of the chromosomes it must never be forgotten that in

them we are dealing only with the most conspicuous form of

germ plasm and that there are much finer elements which in

their turn will demand attention. We may hold to the view of

the individuality of the chromosomes as morphological entities

but nevertheless we must recognize the fact that the substance

of these bodies which stand for parental characters, the idioplasm

of Nägeli, may pass through remarkable changes which are far

from understood. There is much evidence that the parental

idioplasm may mix or combine during synapsis in the organiza-

tion of the spirem from which are developed the reduced num-

ber of bivalent chromosomes. Allen has described the actual

fusion of sets of chromomeres believed to be of maternal and

paternal origin and there are many possibilities of the two idio-

plasms reacting upon one another to bring about intimate and

fundamental interrelations. These become important principles

in discussions of heredity and hybridization and will be con-

sidered later. Allen (:05, pp. 246-252) presents an admirable

. analysis of these problems.

NOTES AND LITERATURE.

ZOÖLOGY.

McMurrich’s Human Embryology.' — In 1902, Dr. McMurrich

published an excellent handbook of human embryology, well adapted

to the needs of students of medicine, and it is a matter of gratifica-

tion to others than the author that its sales have been such as to

demand a second edition. In the preparation of the new edition,

the author has revised the whole, changing the wording here and

there, replacing some cuts and adding two others, while in parts the

text has been re-written so as to incorporate the results of later in-

vestigations. Thus he has added Conklin's explanation of inversion

of right and left sides; the account of the fate of the somatic layer

of the myotome is changed, and with it in other parts modifications

in the account of the derma, and in the idea of a segmentation in the

skin. There is added an account of the chorionic vessels, and a

statement as to the origin of the decidual cells; the account of the

heart muscles has been changed, as has that of the histogenesis of

striped muscle, and Minot's work on the sinusoids has been incor-

porated in the text. i

There are very considerable changes in the account of the arteries

of the trunk and umbilicus; the section on the metanephros has

been re-written, the account: of the lymph nodes has been changed,

as has that of the relations of the corpus callosum and the fornix.

There are also modifications in the statements regarding the endo-

lymph ducts and the formation of the vitreous body. The most

extensive and important changes, however, are in those parts which

relate to the musculature of the limbs, where the author has revised

the matter in the light of his own researches.

Dr. McMurrich has embraced the opportunity to add slightly (24

titles) to the bibliographies and to correct various typographical and

other errors; but as Huxley wrote Foster (Zzfe, vol. 2, p. 65), we

! McMurrich, J. Playfair. 77e Development of the Human Body. A manual

of human embryology Philadelphia, P. Blakiston’s Son & Co., 1904. 2d ed.,

Svo, pp. xix + 17-539, 272 text figs. $3.00.

got

502 THE AMERICAN NATURALIST. [Vor. XXXIX.

wish he would “get rid of that terrible word ‘ urinogenital.’” On

page ıgo the suprasternal bones are spoken of as cartilaginous in

origin, and are also regarded as representing the episternum of the

lower vertebrates, but the episternum is membranous in origin. On

page 202 there is a confusion in relation to the maxillary bones and

“their cartilaginous representatives" in the lower vertebrates. The

printing of the new edition is an improvement on the first, especially

that of the cuts. We commend the work in the highest terms as a

clear; accurate; and modern account of the development of man.

S. M

The Arthropods and Celenterates of the Maldive and Lacca-

dive Archipelagoes.! — In this part of this work are five articles deal-

ing with certain groups of Arthropods and Ceelenterates and a notice

of two parasitic worms. Professor S. J. Hickson treats of the Gor-

gonacea and certain other Alcyonarians, Thirteen species of.Gor-

goniids are enumerated, of which six are regarded as new, all coming

from water of thirty fathoms or less in depth. A single species of

Pennatula was found and a new species of. Eunepthya is described.

Mr. Borrodaile deals with the twenty-three species of hydroids col-

lected, eight of them being new. Lictorella shows some interesting

features, there being, besides the normal hydrotheca, others. nearly

four times as large, each with a hydranth at the bottom. These are

regarded by Borrodaile as gonothecz, although no gonophores were

found, and on this account he would not agree with some authorities

in uniting Lictorella with Lafcea, since in the former there would not

be any Coppinia condition. Synthecium also presents some prob-

lems for. solution. An interesting habitat is recorded for an uniden- -

tified species of Campanularia. It occurred attached to the body of

a sea snake. Borrodaile recalls in this connection a similar associa-

tion of a species of Stylactis with a fish but has overlooked Fewkes’

Hydrichthys mirus which occurred on a teleost on the south coast of

New England. À P

The hermit crabs are discussed by Major Alcock, who enumerates

twenty-six species, of which four are new. The shrimps of. the fam-

ily Alpheidæ were especially numerous, and H. Coutière enumerates

seventy-six species belonging to the group, a large proportion of

these being regarded. as new. Twenty species of Hemiptera are

1 : A

í si J.S., ed, The Fauna and Geography of the Maldive and Laccadive

rehiperagoes. Cambridge Univ. Press, Engi., 1 eee R

; ; * ; . 2, pt. 4, pp- 807

921, pls. 67-87, text figs. : B 905 p p

No. 483.) NOTES AND LITERATURE. 503

catalogued by W. L. Distant, all of which ‘were previously known

from British India.. A. E.. B PM records a species each’of Nema-

tode and Tremaria worms.

J.*8. K.

Townsend's Birds of Essex County, Massachusetts.'— This

book is-all that its name implies and it is much more. Not only is

it one of the most important recent contributions to faunal literature,

but the extended notes on the habits of many birds make it a valu-

able treatise in ornithological bionomics. Of the three hundred and

fifty-two large pages, the first seventy-three consist of nine chapters

on topography and faunal areas; the birds of the ocean, the beaches,

the dunes, the salt and the fresh marshes; and the ponds ; lighthouse

records ; and the ornithological history of the County. It will be

apparent that the stress is laid on the water birds in these introduc-

tory chapters, and this is only natural in view of the fact that Essex

is a maritime county, and that Ipswich, with its beach, marshes, and

dunes, is one of the most interesting localities ornithologically on the

coast, besides being the summer home of the author. So, too, the

biographical matter contained in the Annotated List which makes

up the bulk of the volume is chiefly in connection with the birds of

the sea and the shore, including, however, such passerine species as

the Horned Lark, the Snow Bunting, the Lapland Longspur, and

the Ipswich Sparrow. These notes on the habits of birds are almost

entirely original, the results of Dr. Townsend's patient and pene-

trating observations covering many years of field work as collector

and observer. The treatment of certain of the more interesting

species is minute and well-nigh exhaustive,— though the author very

properly confines himself to the habits as manıfested in Essex

County and has nothing to say, for instance, of the breeding habits

of birds that do not breed in the County. Thus the account of the

Herring Gull occupies seven and a half pages, in which, among

other things, is advanced the theory that the large flocks of gulls

found in summer on the Ipswich shore are made up of daily visitors

from the Maine breeding-grounds. Dr. Townsend also treats the

Black Duck very fully and presents interesting data as to the status

of Anas obscura rubripes, the recently separated subspecies. Con-.

1 Townsend, Charles Wendell, M. D. "The Birds of Essex County, Massachu-

setts, Memoirs of the Nuttall Ornithological Club, no. 3. 352 pp.. frontispiece,

map. 4to, published by the Club, Cambridge, Mass.,.1905. $2.50.

504 - THE AMERICAN NATURALIST. . (Vor. XXXIX.

siderable attention is also paid to the field identification of the

several species. The distinguishing marks of our two cormorants,

for instance, are pointed out, and other birds usually puzzling to the

mere observer are shown to be identifiable in the field with the use

of due care.

It would be unfair to convey the impression that the book is

solely a record of personal experience or that the observations have

been confined to Ipswich and its immediate neighborhood. As a

matter of fact the author is well acquainted with the County as a

whole, and he has made the fullest use of the observations of others,

both published and unpublished, consulting the literature and exam-

ining collections. Nevertheless, the book remains to an unusual

degree a personal achievement, upon which Dr. Townsend is to be

heartily congratulated. The book is written in a direct, forcible

style, with an abundant enthusiasm which is tempered by an emi-

nently scientific attitude of mind and a discriminating sense of

humor. It makes excellent reading even when read consecutively,

and after perusal it should take its place on the ornithologist's

shelves alongside of Major Bendire's Zife Histories.

he volume is excellently printed on good paper and hasa bibli-

ography, a full index, a view of a typical sand dune with adjoining

beach, and a map of the County.

F.H. A,

Notes.— The finer structure of the heart of the higher crustaceans

has been worked out by Gadzikiewicz (Jena. Zeitschr., Bd. 39, p. 203)

with the following results. The heart proper consists of two layers:

an inner muscular and an outer adventitia ; no endocardium is present.

The histological characteristics of these two layers are described in

detail for many crustaceans.

A systematic account of the anatomy of 'Haliotis has just been

published by H. J. Fleure (Jena. Zeitschr., Bd. 39 p. 245). The

author believes that Pleurotomaria and Haliotis are near relatives but

are not derived one from the other. They are probably early deriva-

tives from the common prosobranchian stem but not so early as the

Docoglossz and Fissurella.

The histology of the tunicate blood vessels has been investigated

by Fernandez (Jena. Zeitschr., Bd. 39, p. 325), who concludes that

the blood system in these animals consists of two parts: the propel-

ling part composed of the infolded pericardial wall or heart proper,

and the transmitting part made up of the walls of the blood vessels

and the inner connective-tissue layer of the heart.

CORRESPONDENCE.

A Biological Station in Greenland.

Editor of the American Naturalist. |

Sir: — The great liberality shown in the United States in distribut-

ing money for educational purposes, both from the State and from

wealthy people is, as is well known, not shared in other countries.

It, therefore, still more becomes our duty to take interest in any

cause which will further the study of biology in any part of the world

where the biologist has to deal with financial difficulties.

Dr. Morten P. Porsild, a Danish botanist, has asked his govern-

ment to erect a biological station in Greenland, and as science, in

the truest sense of the word, is international it is of just as great

interest to us in America, as it is to the Danish biologists that such a

station should be erected. In order to show our interest in the

proposed station I thought it worth while to consider, in a few words,

the importance of such a station from a scientific point of view.

The importance of biological stations has been more and more

emphasized as our views of biological problems have widened. We

have just passed over a crisis in which the entire time of the zoólo-

gist was spent in the laboratory, in microscopical study, and have

passed into a wider field, have enlarged the meaning of the word

biology. It does not mean the study of structure merely, but func-

tion, not merely morphology but physiology, and all the factors

which influence it; not individuals only but groups and relations

between groups; it means the science of life in all its branches and

their mutual dependence. on each other. The recent investigations

. of Professor J. Loeb have emphasized this fact. The whole field of

experimental zoólogy emphasizes the importance of studying animal

life and of studying it scientifically. Many of our greatest biological

problems are to be solved by studying outdoor zoólogy. A great

work is yet to be written on how and to what extent selection works

in Nature. The question of variation is left to the student of the

complex phenomenon of environment under which these animals live

and develop and how these conditions effect a given species ; it is not

a question for the mere systematist but the student of animal life, of

506 THE AMERICAN NATURALIST. (VoL. XXXIX.

microphysiology for the student of biology in the widest sense of the

word. To study phylogenetic development from structures only is

to study results without causes. The important study of relations is

a study of animal life. The whole field of economic zoólogy asks for

better knowledge of outdoor zoólogy. In a word,the recent path

of zoölogical investigation has been fo go back to the methods of

our great master, Charles Darwin, and use as an aid our detailed

microscopical study which has absorbed almost the entire time of

the zoölogist for years.

If these are true interpretations we must hail every new oppor-

tunity given the student of zoólogy in any part of the world to study

animals in their natural surroundings, and on a scientific basis.

Especially is such the case when we are hoping to get a biological

station in Greenland where the conditions and fauna are so different

from those of any place where similar stations are found. The stu-

dent of variation will then have an opportunity of transferring ani-

mals from one extreme climate to another. A thorough knowledge

of how the fauna is adapted tothe surroundings in a land where the

sun never sets for three months and never is seen for a still longer

period of thé year will surely yield some interesting results.

All the great groups of invertebrates, and vertebrates with the

exception of the amphibians and reptiles, are represented in Green-

land. The flora is surprisingly large so there is no lack of oppor-

tunities for study as soon as a well equipped laboratory is established

there. According to the estimate of Mr. Porsild the trip from Cop-

enhagen and return and one year's study in Greenland would, under

those conditions, be reduced to one third of the present expense or

to $375. ;

T economic importance of such a station I have had various

opportunities to show, and I need not point them out here but enough

to say that Denmark ought to learn from the United States to protect

her industries of hunting and fishing, and this can only be done in :

haee: by having competent people there to protect these indus-

es.

It iun be hoped that the government of Denmark will do its

share in furthering the study of biology by offering the small sum of

MAU rea reg for such a station which will be of great value

ntific and an economic point of view.

MARTIN E. HENRIKSEN.

OHIO STATE University.

No. 463.] | CORRESPONDENCE. 507

Fleas and ‚Disease. : :

Editor of the American Naturalist.

Sir :— No less epoch-marking than the announcements first made

of the connection of mosquitoes with malaria and yellow fever, is the

news which: now comes-through Dr. Ashmead, the leprosy expert of

New York, that Dr. Carrasquillo of Bogota has found the bacillus of

Hansen in the intestinal canal of fleas. ‘The rapid progress of

leprosy after introduction into some of our flea-infested southern

cities, from local endemicity to alarming epidemicity, is, according

to Dr. Ashmead, probably to be credited to inoculation by flea

bites.

In connection with the -investigation of the relation of fleas to

bubonic plague, it has alread} been shown by the writer (Proc. U. S.

Nat. Mus., vol. 27, 1904), that the fleas of rats in the warmer

regions of the earth are close relatives of the flea specific to human

beings, and thus, far more likely to bite human beings than are the

fleas of rats in the colder regions, which are only distantly related to

Pulex irritans. It is now necessary to know if any of these southern

rat fleas — of which there are a number of species — voluntarily bite

human beings. :

These investigations, and now the new lines brought into striking

prominence by Dr. Ashmead’s announcement, make it of first impor-

tance that a complete study be made of all the species of fleas occur-

ring on rats, mice, dogs, cats, and human beings throughout the

United States and tropical America, since any well founded medical

and bacteriological investigations of the subject must be based on a

thorough scientific knowledge of the fleas themselves, just as in the

case of the mosquitoes in their relation to yellow fever. The utmost

gravity of the possibilities involved not only justifies but renders im-

perative a careful and complete survey. The writer has in progress

such a work, in continuation of extensive papers on the fleas already

published. Residence in the tropics and in a leprosy center, together

with the hearty coöperation of Dr. Howard of Washington, Dr. Lutz

of Sao Paulo, Brazil, Dr. Carter of the University of Texas at

Galveston, and others, has made possible a good beginning. It is

hard to see how anything like a complete survey could be made with-

out also the active coöperation of college and medical men in every

part of these regions, the Hawaiian Islands, and the tropical regions

of the far east. The simplicity of the apparatus needed (tweezers,

508 THE AMERICAN NATURALIST. [Vor. XXXIX.

small homceopathic vials of alcohol, and several rat traps) and the

ease with which material can be gathered from rats, dogs, cats, and

human beings, should make possible the readv coóperation of all

biologists and medical men and a hearty invitation is herewith ex-

tended to all such and to any other persons interested. As large

series of specimens as. possible should be taken and full data as to

locality, host, etc., should be inserted in every vial. A direct report

will be immediately returned for all specimens sent either to the

writer or to Dr. L. O. Howard, Government Entomologist, in Wash-

ington, U. S. A., and full published credit will later be given for

every sending.

It will greatly facilitate the rapid progress of the work if entomo-

logical, zoólogical, medical, and pharmaceutical journals the world

over will kindly copy this notice.

C. F. BAKER.

ESTACION AGRONOMICA,

SANTIAGO DE LAS VEGAS, CUBA.

(Vo. 462 was issued June r 3, 1905.)

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AMERICAN NATURALIST.

Vor. XXXIX. August, 1905. No. 464.

A SYSTEMATIC STUDY OF THE SALICACE.

D. P. PENHALLOW.

In attempting a discussion of the Salicacez from the stand-

point of their ancestry, as presented in the woody structure of

the mature stem, a first step involves comparison with previously

existing forms and with closely related types now extant, in

order to determine the general phylogenetic sequence and the

position which the group at present occupies. We are there-

fore led, at the very outset, to ask: (1) what is the nature of

the evidence to be derived from paleontology, and what is the

bearing of such evidence; and (2) what is the nature and bear-

ing of the evidence to be derived from the structure of existing

species? The Salicacez as we now know them, are altogether

confined to two genera— Populus and Salix — of very wide

: distribution in north temperate latitudes whence they extend

beyond the extreme northern limit of tree growth within the

polar circle, being there reduced to prostrate shrubs. It is

quite possible that the family may have been more extensive in

early or middle Mesozoic time, but the evidence now available

as derived from their fossil remains, leads us to the supposition

"that it has not been, at any previous time in its history, of a

more comprehensive character. In common with many other

509

510 THE AMERICAN NATURALIST. "([Vor. XXXIX.

families of Dicotyledons, it made its appearance very abruptly

in the Cretaceous age, whence it has continued through suc-

ceeding formations, appearing with prominence in the Pleis-

tocene where its remains form a distinctly connecting link with

existing species, with many of which they are more or less

identical.

An analysis of the Salicacee based upon the enumeration

of the Index Kewensis, shows that there are at the present time

no less than two hundred and seventy recognized species, an

altogether unusual proportion for a family embracing such a

limited number of genera. Of these, twenty-two belong to the

genus Populus, while two hundred and forty-eight belong to the

genus Salix.

The poplars are preéminently a type peculiar to the northern

hemisphere, and in their chief aspects they have a strong tend-

ency to a boreal habit, the one exception to be met with in

the subtropical P. mexicana offering no material contradiction

of this law. P. ciliata of the Himalayas, though reaching a

latitude far below that of most representatives of the genus,

nevertheless conforms to the temperate habit of the group by

virtue of the somewhat high elevations at which it grows. Six

species range from Japan through China, Mongolia, and Siberia

to Central Asia, while the western extension of the genus is

chrried through northern and central Europe as far south as

Spain and Italy. In the western hemisphere, no less than ten

species are to be met with, ranging from Mexico as the extreme

southern extension, thence northward as far as the arctic circle

where P. balsamifera appears to establish the limit of develop-

ment. The very remarkable isolation and localization of the

various species is one of the most prominent features disclosed

by an examination of these plants. P. mexicana is confined to

Mexico and similarly P. ciliata is peculiar to the Himalayas.

P. adenopoda is restricted to China as P. sieboldii is to Japan ;

while P. przewalskii of Mongolia and P. pruinosa of Siberia, as

also P. euphratica of Central Asia, give emphasis to this strong

segregation, since they are as wholly distinct from the European

and American species as are those of the last two regions from

one another. In only one instance does there seem to be any

No. 464.] STUDY OF ITHE SALICACE.. SII

connecting form. This is presented in the ubiquitous balsam

poplar of Asia and North America which not only serves to

connect the types of both hemispheres, but it gives to the

genus a greater range of latitude than any other species. Evi-

dence of this nature would naturally lead to the supposition that

P. balsamifera may represent a more generalized type ancestral

to many of the associated species. But on the other hand, the

very extensive distribution of distinct species occupying essen-

tially isolated and often very widely separated regions, suggests

a more general dispersal during Cretaceous and Tertiary time,

and their eventual restriction to more limited areas through the

operation of important physical agencies, with the survival of

the more resistent but not necessarily the oldest species. In

particular it is conceivable that such restriction may have been

brought about in one of two ways: (1) the elimination of the

ancestral type or types, of which P. balsamifera may possibly

be regarded as the sole survivor, would tend to leave the

descendants isolated as now found; (2) the ancestral forms

having disappeared at a comparatively early period in the his-

tory of the genus, more recent physical changes in the earth's

crust and in climatic conditions would give rise to more or less

profound alterations in distribution in such a way as to effect a

more pronounced segregation and localization. That such

causes have been operative in glacial times is well known, and

they have lefta very definite impress upon the distribution of

the existing flora of this continent, as particularly indicated by

the various forms of alpine vegetation (Gray, '89, vol. 1, p. 122;

vol. 2, pp. 24, 142, 260) and by such special arborescent forms

as Larix americana, Sequoia, Pseudotsuga douglasii, etc. (Pen-

hallow, : 04).

From this analysis it appears that there are twelve species of

poplar peculiar to the Old World and nine species peculiar to

the New World, with one species common to both. From this

circumstance it would be natural to conclude that this is essen-

tially an Old World genus, but the slight numerical difference

noted would make such a generalization unsafe without con-

firmatory evidence derived from the paleontological record to

which appeal must also be made for an answer to several other

questions that have already arisen.

512 THE AMERICAN NATURALIST. (VoL. XXXIX.

Like the poplars, the willows are a type essentially peculiar to

the temperate regions of the northern hemisphere, though they

represent adaptation to a greater diversity of climatic conditions

and thereby greatly extend the northern and southern range of

the family as a whole. With the exception of about 2 percent

—an altogether insignificant proportion—they are of a conti-

nental character. Nevertheless, in the S. junghuhniana of

Java, S. sumatrana of Sumatra, S. canariensis of the Canary

Islands, S. madagascariensis of Madagascar, and S. occidentalis

of the West Indies, types which are strongly segregated and

localized, their very restricted range is in close proximity to the

corresponding vegetation of the continental areas in which they

must have had their origin and from which they must have been

isolated at a comparatively late period as shown by Wallace ('80).

It is these insular forms which are chiefly concerned in the

extreme southern extension of the genus, since the six Mexican

and eight north African species range considerably farther north.

The extreme isolation of S. Zumboldtiaua in South America

affords at once an illustration of the extent to which dispersal

must have been carried in former geological times, and of the

potency of the influences which have tended to a greater restric-

tion of geographieal area.

Of the one hundred species common to Asia, twenty-four are

found within the Himalayan region, while seventy-three are more

peculiar to the temperate and boreal regions of Japan, China,

Siberia, and Central Asia. In Europe no less than eighty-four

species give a range to the genus which extends from the Medi-

terranean on the south to the polar regions where the very

diminutive S. Polaris with an extreme height of about 3.3 cm.,

defines the northern limit of growth. In North America, apart

from Mexico, seventy-two species similarly extend the genus over

a wide range of latitude, their northern limits being defined by

the boreal S. ovalifolia which also ranges southward on the sum-

mits of lofty mountains, as far as Mount Washington in New

Hampshire. Ubiquitous species are much more common than

among the poplars, and there are no less than 23 which are

more or less common to the several continental regions as exhib-

ited by the following synopsis. -

No. 464] STUDY OF THE SALICACEE. 513

Community of Species of Salıx.

Europe and Asia à : ; i ; ; ; à 14

Europe and North America i : : i 7

Europe and Africa and Asia . ; : ; ; ; I

Asia and Africa : 3 i : I

Qə

In determining these relations, the very pronounced isolation

of the Japanese and Himalayan species stands out with great

prominence and lends emphasis to the idea of segregation in a

previously continuous flora. From the facts thus presented, it

is obvious that the willows are preëminently an Old World

genus, and that, although their dispersion has a tendency to

greater diffuseness than in the case of the poplars, like them

they essentially belong to temperate regions, and their tendency

is on the whole boreal, rather than austral; so that with respect

to the Salicaceæ as a whole, it may be said to be a distinctly

temperate and boreal family of wide dispersion within the north-

ern hemisphere, with its center of distribution in Asia where it

presumably had its origin. A summary of these geographical

relations will serve to make the foregoing analysis more clear.

In the light of these facts it becomes pertinent to ask whether

the family as now known represents a type of vegetation which

is yet in process of evolution, if it is a side line which has

recently attained to the full limit of development and which is

therefore terminal, or if it attained the culmination of its devel-

opment in some previous geological age and is now in a state of

decline comparable with that exhibited by the Lycopodiaceæ

and the Equisetaceæ. The comparatively recent origin of these

plants, if we are to judge them by the standards which have

been set by other groups, the general phylogeny of which is

fairly well known, would naturally lead us to support the first

hypothesis or at least the second, and to reject the third as

improbable. But such generalizations are unsafe unless sup-

ported by other well established data, and it therefore becomes

necessary to inquire somewhat particularly into the nature of the

evidence afforded by the geological history of these plants.

THE AMERICAN NATURALIST.

[VoL. XXXIX.

Geographical Distribution of the Salicacee.

Old World. New World.

z &

& z A ;

31:5 l3 Sr Š

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Salix Ery 2 73 I 8 84 72

100 10 84 80

248 194 80

Percent 0.410.4}0.4| 9.68 29.43 |0.4|0.4| 322 33.87 |0.4|04| 2.41 | 29.03

40.32% | 4.03% 33.87% 32.26%

: 78.22% 32-26%

Duplications 8.19% 2.19%

Total 70.03% 29.97%

Populus | I 6 | | 6 | I 9

en OEE Nery fag co FRE N

22 y

13 10

Percent 4:54 27-27 27.27 4.54 | 4991

59.00% 45-45%

Duplications 2.68% 1.86%

Total 56.41% 43-5970

Salicacex 78.88% 33-33%

Duplications 9-63% 2.58%

Total 69.25% 30.75%

No. 464.] STUDY OF THE SALICACE $15

Our knowledge of the fossil Salicaceze had its origin in the

work of Heer upon the fossil plants from the Cretaceous forma-

tion of Greenland, through his description of Populus primeva.

The occurrence of this species in the Kome beds not only

afforded the first real evidence of the occurrence of these plants

in previous geological time, but it at once served to suggest the

essentially primitive character of the Salicacee as a whole

among Dicotyledons—an idea subsequently strengthened by

the discovery of both Salix and Populus in the Potomac forma-

tion, as well as in the Kootanie beds of Montana. This idea,

then, has persisted to the present day and finds repeated ex-

pression in the various treatises on fossil plants, although the

acceptance of such a view is not based in any case, upon trust-

worthy facts derived from a critical comparison of distribution,

a knowledge of the phylogeny of the group, or an acquaintance

with the anatomy of either recent or extinct species. Paleonto-

logically it is of interest to determine the position of the Sali-

'cacez relatively to the other families associated with it in the

Cretaceous and Tertiary deposits, and for this purpose the flora

carefully compiled by Dr. Knowlton (98) offers the most

reliable basis now available. Among forty-five families of

angiosperms now known to constitute the flora of the Creta-

ceous and Tertiary ages in North America, it will be found that,

‘geologically speaking, the Salicaceze is by no means the primitive

group which seems to be implied by the position usually assigned

to it, but that it really occupies a position which is the twenty-

fourth in a series based upon the percentage ratio of occurrence

in the two great geological periods. Such a series has as its

lowest member, the Proteacez which is preéminently a Creta-

ceous family, bearing to the Tertiary the ratio of 19:0. The

same is also true of the Menispermacez with a ratio of 17:0,

closely followed by the Araliacez (6:0) and the Euphorbiacex

(2:0). Atthe other extremity of the series we find such fami-

lies as the Hydrocharidaceze (0:2), Lemnacez and Simarubacez

(0:3), Typhacez (0:4), Onagracez (o: 5), Naiadacex (0:7),

Zingiberaceze (o : 17), and the Cyperaceze (o : 20), all of which are

manifestly typical Tertiary plants. About midway of the series

the Salicacez are associated with the Urticacee with a ratio of

1: 1.47 and with the somewhat similarly distributed Platanacez,

51 6 THE AMERICAN NATURALIST. [Vor. XXXIX.

Myricacez, Cornacez, and Sapindacex. There is thus a very

strong suggestion (1) that the Salicacez is in no sense a primi-

tive family from the standpoint of geological succession, and (2)

it is, as a whole, much more characteristic of the Tertiary than

of the Cretaceous, more especially as a closer analysis of the

one hundred and forty-one known species shows that this rule

applies to each of the constituent genera as well as to the entire

family, though more conspicuously to the genus Populus than to

Salix. Thus we find that the forty-seven Cretaceous species

embrace 34 of Populus and 23 of Salix, while the eighty-four

Tertiary species embrace 59 of Populus and 25 of Salix, making .

the ratio of Cretaceous to Tertiary 1:1.75 for the former and

1: 1.09 for the latter — ratios which tend to indicate that these two

genera and so the family as a whole, were in process of develop-

ment even in Tertiary time, a conclusion which is in apparent

accord with the recent origin of the family.

Comparison of Cretaceous and Tertiary Floras.

Seq. 3 Cretaceous | Tertiary

No. Ratio. No. Percent. No. Percent.

Proteacex I 19 : 0.00 19 1.09 0.00 0,00

Menispermacex 2 17 : 0.00 1j 0.98 0.00 0.00

Araliacex 3 6:000 — 5D 2 0 0.00 —

Euphorbiacex 4 2 : 0.00 2 0.11 0.00 0.00

Passifloracex 5 I : 0.00 I 0.06 0.00 0.00

Asclepiadacee 5 I : 0.00 I 0.06 0.00 0.00

Myoporinex 5 I : 0.00 I 0.06 0.00 0.00

Convolvulacee 5 I : 0.00 I 0.06 0.00 0.00

Bromeliacee 5 I : 0.00 I 0.06 0.00 0.00

Casuarinex 5 I : 0.00 I 0.06 0.00 eoe

Sterculiacex 6 [tolg 15 086 a 9H

Myrsineze 7 Li ois 6 0.34 I 0.06

Myrtacex 8 1:0.18 II 0.63 3 9H

Hamamelacex 9 [:035 4 0.22 I 0.06

Magnoliacex 10 1: 0,31 45 2.60 20 1.15

Thymeleacex II 1:00,33 3 0.17 I 0.06

Anonacee 11 FIG 3 0.17 I 0.06

Araliacex 12 I : 0.36 47 2.71 17 o.98

Sapotacex 13 I : 0.50 à 022 2 0.11

Lauracex 14 1:056. © — 308 39. r

Vitacex 15 1:06. 36 105 16 0.92

No. 464.)

Celastracex

Leguminosze

Aracex

Ebenacez

Ericaceae

amnacex

Aquifoliacex

Aristolochiacex

osacex

Juglandacez

Liliaceze

STUDY OF-THE SALICACEZ.

Ratio.

Cretaceous

No.

—

0000000000000 PL O0 oo ANN - HW” =

Percent.

1.73

1.84

0.22

0.75

1.03

0.06

0.11

Terti

No.

—

517

ary

Percent.

5 18 THE AMERICAN NATURALIST. [Vor. XXXIX.

The succession exhibited in this table brings into prominence

the idea that such families as the Leguminosz, Vitacez, Eri-

cacex, Magnoliaceze, Convolvulacez, etc., are inferior to the

Salicaeze which is, in turn greatly inferior to the Cyperacex

from an evolutionary point of view ‚when considered solely in

the light of their geological succession ; but the sequence which

is thus established is found to be utterly at variance with that

usually adopted on the basis of morphological evidence which

for obvious reasons must be regarded as the more trustworthy

guide. Such discrepancies between the morphological and the

geological succession, in our opinion, should not be so great as

seem to be suggested by the available data, and no doubt they

will diminish as our knowledge of the fossil representatives

becomes more nearly complete, but that such discrepancies may

be anticipated, and that they are to some extent to be regarded

as a normal result of rapid evolution along many diverse lines of

development, is a reasonable supposition. The Mesozoic age

was a period of very great diversification among plants in con-

sequence of the profound physical changes which had taken

place in the atmosphere as well as in the configuration of the

surface of the earth, and the fact that as a product of previous

development, plants were in a condition to be widely and pro-

foundly influenced by comparatively slight modifications of exter-

nal conditions. The very great number of families and genera

and even species of angiosperms which abruptly appeared in the

Cretaceous, presenting as they did types of vegetation wholly

unlike those of previous geological periods, indicates that the

parental forms must have had their origin in the early Meso-

zoic and possibly as far back as the Permian, since our accept-

ance of the general principles involved in De Vries' mutation

theory does not permit us to consider as possible, such phe-

nomenal transitions as would be involved in the application of

that theory to the case under consideration ; while on the other

hand all paleontological evidence, as well as the evidence derived

from existing types, confirms us in the belief that such highly

organized forms could have arisen in the main, only through a

long series of transitional forms occupying great periods of time.

For the same reasons also, we are led to believe that the great

No. 464.] STUDY OF THE SALICACEE. 519

diversification of the Cretaceous flora must have been initiated

at correspondingly early periods, though the general succession

of types of which we have knowledge, would indicate that it did

. not gain full expression until about the time of the Middle

Cretaceous. This diversification was no doubt the natural

response of vegetation to the profoundly changed physical con-

ditions, chiefly climatic, which followed the close of the Carbon-

iferous age and resulted in a diminution of the carbon dioxide

of the atmosphere to about one-twentieth of its original volume

with a consequent reduction of atmospheric density ; a general

purification of the atmosphere whereby it became more readily

penetrated by the sun's rays; a lower and less equable temper-

ature with more localized climates, and conditions which, as a

whole, were more favorable to a more varied mesophytic type of

vegetation. Under such circumstances, involving as they did

a more abundant supply of oxygen, the general activities of

growth became greater; the transformation of carbon dioxide

into assimilable products became proportionately larger; in

response to the more favorable conditions of light and air, the

foliage became broader and acquired an increased functional

capacity ; and with the augmentation of capacity for the storage

of energy thus made possible, there were increased possibilities

of, as well as strong tendencies toward diverse development in

which special mutations no doubt played an important part, in

response to even comparatively slight variations in environmental

conditions. From this point of view it is not difficult to under-

stand that among the numerous offshoots from the main line of

descent there would be very varying degrees of activity, and it

is readily conceivable that plants of a low phylogenetic position

might be held in numerical abeyance for a long time, while

others, originating at a higher level but more favorably situated

and more capable of responding to their environment, might at

once outdistance them in number of species or of varietal forms.

Under such circumstances the geological succession might lead

to erroneous conclusions as to the true phylogenetic sequence.

Such a view is suggested and supported by a comparison of

many well known examples among existing species. In this

way it would be possible for a relatively superior type of organ-

520 THE AMERICAN NATURALIST. | (Vor. XXXIX.

ization, and one occupying a higher position in the morphologi-

cal scale, to occupy an inferior position in the geological scale,

and thus to appear antecedent to morphologically inferior types.

From the foregoing considerations it is clear that geological.

data cannot be wholly relied upon to furnish a correct solution

of questions bearing upon the evolution of plant forms, and this

is especially true with respect to the broad-eaved angiosperms

for reasons which will be described more fully on a subsequent

page. Interesting as these various speculations may be, as

applied to the Salicacex they nevertheless lack an essential

foundation which can be obtained only by a more searching

scrutiny of the family as a whole, and of its component genera,

with respect to their more detailed distribution in Cretaceous

and Tertiary time, as well as at present.

Nowhere has it been possible to obtain so complete a record

of the Cretaceous flora as from the exposures to be met with in

Greenland and the United States, and the systematic way in

which the various horizons have been worked out, affords a very

satisfactory basis for a knowledge of the geological succession

of species and genera. In his studies of the Cretaceous flora of

Greenland, Heer found that out of a total of 88 species from

the Kome beds, only 5.68% were Monocotyledons, while the

Dicotyledons were represented solely by Populus primeva to

the extent of 1.14 %. In the Cenomanian flora of the Atane

beds, there was a remarkable increase of Dicotyledons amount-

ing to 50.09 % ina total of 177 species; while from the Patoot

beds of the Senonian, 59.48 % were Dicotyledons out of a total

of 116 species, thus showing a marked development of this type

of plants toward the close of the Cretaceous. This ratio be-

tween the three divisions of the flora also appears to extend

very largely to the Salicacez in particular, with respect to

which we find 27.40 %, 42.40%, and 30.10 % respectively for the

three horizons. An analysis of the family, however, shows that

this relation does not altogether hold in detail for the individual

genera. Thus in Salix the percentages are 41.40, 41.40, and

17.20 which approximates to the results for the family as a

whole with respect to the very evident falling off in the Upper

Cretaceous. Nevertheless this is much more marked in the

No. 464] STUDY OF THE SALICACEE. , $41

genus than in the family, and suggests that the former is in

process of decline, a conclusion which seems to be directly

opposed by the evidence afforded by the ratio of extinct and

living forms. Populus gives 18.10%, 43.10 %, and 38.60 % for

the three horizons with a maximum development in the Middle

Cretaceous.

Distribution of Salicace@ in Cretaceous of United States.

SALIX.

Lower. Middle. Upper.

Salix stantoni x

mattawanensis x

meekii x

protefolia x x

uf exuosa x x

T lanceo x

a linearifolia x

" longifolia x

cuneata x

deleta x

7 x

inequalis x

membranacea x

nervillosa x

newberryana x

ciftca x

purpuroides x

sp. x

s$. x

Sp. x

sp. x

Saliciphyllum ellipticum x

longifolium x

garvifolium X mm

Species 26 11 5

Percentage distribution 42.3% 46.1%, 19. 2^;

522 THE AMERICAN NATURALIST. (VoL. XXXIX.

Distribution of Salicacee in Cretaceous of United States.

POPULUS.

Lower. Middle. Upper.

Populus berggrent ; x x

hyperborea x

stygia x

mutabilis Her x ;

melanarioides

wardii

AARAA RX

mutabilis ovalis ? -

apiculata : X

aristolochioides

auriculata x

cordifolia

elliptica x

X X

harkeriana

latidentata x

kansaseana x

longior x

leuce

microphylla

potomacensts

protozadachi

rectinervata

trinervis

sp.

XXXXXXX

sp.

Populites tenuifoitus

cyclophylla

elegans

lancastriensis

litigiosus

microphyllus

probalsamifera x

XXXXXX

X X

winchelli

Populophyllum crassinerv

hederaforme

reniforme

«| xxx

Species 42

Percentage distribution : 18.1% 43.1% 38.67;

No. 464] STUDY OF THE SALICACEE. 523

Again, comparisons with existing species are instructive. If

all the various forms now recognized are to be regarded as valid

species, then it would appear that the genus Populus must have

attained to its full development in the later Cretaceous or pos-

sibly early Tertiary time, since when it has been in a process of

slow decline, or at least it has made no substantial progress. A

very noteworthy feature of such comparisons appears in the

somewhat abrupt increase among the Salicaceze in common with

other Dicotyledons, in the Middle Cretaceous, especially in the

Dakota group. A ready explanation of this phenomenon on

purely botanical grounds might be found in the facility with

which hybridization gives rise to very stable. forms, and it is in

all probability true that such hybridization is accountable in

large measure for the multiplication of forms or species in past

times as it is known to be at the present day ; but to the geolo-

gist this would probably not afford an adequate reason, since he

recognizes the important extent to which “accidents ” as deter-

mined by exposure of strata, methods of preservation, etc., con-

stitute very definite and often controlling factors in the number

and kinds of plants which may be yielded by a given formation,

in which sense Dr. Knowlton has observed * that though some

types of the Cenomanian, as shown by the leaves of the Dakota

group, generally remain distinct and plainly defined in the

vegetation of some of the subsequent formations, the chain of

evidence is not always continuous. A number of these, for

example, still remain unrecognized in the Upper Cretaceous,

though present in more recent strata of the Laramie or of the

Tertiary. We know very little as yet of the flora of the Senon-

ian or of intermediate stages between the Dakota and the Lar-

amie groups. But judging from recent discoveries in Wyoming,

Montana, Canada, and Vancouver Island, we have been able to

recognize in the scanty materials obtained, the presence and

therefore the persistence of some of the primitive or more

ancient types, and it is most. probable that further research will

complete the evidence of the persistence and fepresentation of

the types of the Dakota group up to the Laramie, as clearly as

it is observable in this flora and through the different stages of

the Tertiary to the present time (Lesquereux, '92).

524 THE AMERICAN NATURALIST. (VoL. XXXIX.

We are now led to ask: * What is the nature of the evi-

dence, with respect to the particular form and value of the plant

remains, upon which our knowledge of the geological succession

is based?” Of the internal structure of the fossil Salicaceze we

as yet know nothing, for with the exception of a few specimens

from the Pleistocene, the wood of these plants has not yet been

brought under examination, and we are therefore denied one of

the most definite means of distinguishing with certainty not

only the various species and genera, but also the relations which

the members of this group bear to one another and to other

groups. That fragments of the stems of willows and poplars

must sooner or later be found and brought under examination,

is altogether probable, and as an essential provision for the

proper recognition of the various species at such times, it is

important that accurate diagnoses of existing species should be

made.

The only evidence at present available for the recognition of

members of the Salicacez, is in the remains of their leaves which

are too often found in a very fragmentary condition and other-

wise unsatisfactorily preserved. Recalling the extent to which

hybrid and variable forms occur in this family, and the often

extreme differences which may arise in the same species as

shown by Ward ('88), Holm ('9o, '95), Berry (:01—:03, :02a,

:02b), and Penhallow (: O4), itis readily seen that the numerical

distribution of these leaf forms in geological time cannot be

regarded as affording an accurate basis upon which to found a

knowledge of succession, and such remains can never be of

more than approximate value with reference to an exhibition of

the most general relations. Under these circumstances, as

pointed out by Holm ('95) some years since, “a careful study of

the recent flora is absolutely necessary when it is desired to

identify fossil leaves with even an approximate degree of correct-

ness. The plant must be studied as it stands amidst the sur-

roundings to which it has adapted itself and which its leaves

reflect." It is altogether probable that a more complete and

detailed knowledge of the Salicaceze would show that the pres-

ent forms which are recognized as distinct species, in reality

represent, in. many cases, only variations of the same species.

No. 464.] STUDY OF THE SALICACEE. 525

This idea is emphasized more particularly in the case of the

willows by the observation that Salir protefolia has no less than

four variants, or five forms in all, as presented by the generally

accepted specific type and the varieties designated as flexuosa,

lanceolata, linearifolia, and longifolia — forms which are all

characteristic of the Dakota group, though S. protefolia and S.

protafolia flexuosa are also found in the lower Cretaceous. We

therefore find that so far as the geological evidence alone is con-

cerned, it throws no light whatever upon the possible ancestry

of these plants, it affords absolutely no clue as to their relations

to other groups of plants, and it gives no very trustworthy

information as to their present position in the scale of develop-

ment. But when such evidence is taken in conjunction with

that derived from a knowledge of the family as at present

existing, the following conclusions appear to be fully justified :

(1) The Salicacez as a whole is an Old World family with

its probable center of distribution in southeastern Europe and

Central Asia.

(2) It is a family with a strong tendency to a boreal habit

which has become more definitely emphasized since Tertiary

time.

3). The present tropical and subtropical members of the

family, probably represent the relics of a wider dispersion in

Cretaceous and Tertiary time, which have been isolated and

localized as the result of more recent contraction in the family

as a whole.

(4) The family at present affords strong proof of a temperate

climate. In Cretaceous time it was compatible with a much

warmer climate than at present, as indicated by the survival

of tropical and subtropical forms; but changes more recently

effected, have made its tendencies boreal rather than tropical.

(5) The family had but a feeble development in the Lower

Cretaceous, but become greatly augmented in the Middle Cre-

taceous.

(6) Itis a family which may be regarded as still in process

of development.

(7) The process of victi. is chiefly expressed in the

genus Salix which shows a very great increase since the Middle

Cretaceous.

526 THE AMERICAN NATURALIST. | [Vor. XXXIX.

(8) The process of evolution is less definitely expressed in

the genus Populus which shows but little advance since the

Middle Cretaceous, and it may possibly be regarded as having

attained the culmination of its development.

While it is impossible at present to discuss the anatomy of

these plants in the light of their ancestral forms, the study of

existing species may serve an important purpose as a working

basis for future paleontological research in this direction, and it

may eventually prove to be the key which shall unlock the door

now concealing important records of the past. In this sense it

is necessary to formulate a theory of possible descent as a

working hypothesis, and this can be obtained only through a

detailed study of. the anatomy of the Salicacez in cemparison

with what has already been ascertained to represent certain laws

of development in the gymnosperms. This hypothesis may be

stated briefly before proceeding to a discussion of those anatom-

ical details which may lend it support.

A comparison of the ferns, arborescent pteridophytes such

as Calamites and Lepidodendron, and the arborescent types of

gymnosperms and angiosperms, shows, in general terms, that

the so called wood increases in proportion to the requirements

of mechanical support. This latter is usually met by the dis-

position of the tissue in such a manner as to afford the most

effective resistance to external stress, and it is therefore dis-

posed in monostelic stems, in the form of a definite cylinder

which constitutes the secondary xylem structure. It is also an

essential feature of the same law, that the secondary xylem

should be in all cases radially external to the protoxylem, and

that its augmentation in secondary growth of the stem must

always arise in radial succession.

In the polystelic ferns where the secondary xylem consists

almost wholly of vessels and the wood elements are numerically

subordinate, these latter are distributed among the other ele-

ments of the xylem and do not form a specialized mechanical

region. Such strengthening as these plants require, is accom-

plished in the first instance by the sclerenchymatous bundle

sheath, and secondarily by the more general conversion of the

fundamental tissue into hard sclerenchyma. It is similarly

No. 464.] STUDY OF THE SALICACEE. 527

impossible to compare such plants in any direct way with the

polystelic angiosperms in which the mechanical tissue generally

encloses the vascular structure in a more or less definite sheath

which exhibits a more or less clearly defined relation to mechan-

ical stress. While, therefore, for the purposes of our present

argument, it is impossible to introduce exact comparisons with

any of the polystelic forms of stems, we must nevertheless con-

clude that the secondary wood, in whatever form it may be dis-

posed, must be regarded as differentiated to meet mechanical

ends as shown by Williamson (71) in his various elaborations of

the Calamitean structure and as more recently stated by White

(105); but a knowledge of the relations existing between the

protoxylem and the secondary xylem requires a more critical

examination in detail, in order to determine the course of devel-

opment which has given to the gymnosperms and the dicotyle-

donous angiosperms, the peculiar structural aspects distinguishing

them respectively. This will constitute the subject of a special

paper ata future date, and in the meantime it will serve our

present purpose to state briefly the fundamental conceptions

which form the essential features of our hypothesis. In order

to make our point of view more clear, it will first be necessary

to state concisely what has been shown to hold true of the

gymnosperms with respect to the evolution of the secondary

vascular structure and its economic aspects in relation to the

requirements of support, as well as its physiological ré/e in the

conveyance of nutrient fluids.

The origin of the gymnosperms in the Cycadofilices, or at

least a portion of them, is now generally accepted as an estab-

lished fact. The essential starting point for the evolution of the

vascular cylinder is therefore to be found in the scalariform and

spiral vascular elements of the Cycadofilices or their filicinean

ancestors which constitute the entire vascular bundle of those

plants, and which, in the gymnosperms, constitute the protoxy-

lem structure only. The relatively greater extent to which the

mechanical elements are developed in some of the Cycadofilices

and in the Cycadacez as a whole, is in direct response to the

somewhat more arborescent tendency of these groups as partic-

ularly expressed in certain genera; while the fact that they do

528 THE AMERICAN NATURALIST. (VoL. XXXIX.

not in any case attain to the extreme preponderance noted in the

Cordaite and Conifer, etc., is precisely in harmony with the

general approximation of the Cycadacez as a whole to their

filicinean ancestors and the lack of need for that peculiar form

of mechanical support which is demanded by trees of large size,

and which is provided in all the arborescent forms of the seed

plants. With these statements it will be unnecessary to follow

the Cycadacez in further detail, but rather to consider the

course of events in the more arborescent Cordaitales and Conif-

erales where the analogy with the angiosperms is closest. It is

now a well recognized fact that the protoxylem of the gymno-

sperms constitutes a transition zone within which peculiar and

often somewhat remarkable evolutionary changes take place.

The protoxylem or transition zone is a region peculiarly sensi-

tive to the controlling influences of environment, and its response

is so immediate as to give rise to structures of a very diverse

nature. This has been shown to be true of the Cycadacez

(Penhallow, :04c) to a notable extent, while it is no less promi-

nent in the Cordaitz, both of which groups are of a recognized

primitive character among gymnosperms and stand in somewhat

close relations to their Cycadofilicinean ancestors. But a very

important difference exists between these two groups with respect

to the survival of the protoxylem and the precise composition

of the secondary wood. In the Cycadaceze the growth of the

stem in annual increments involves the complete repetition of the

entire xylem structure and the formation of secondary growth

in a manner which is to be met with in no other group of gym-

nosperms. The growths of successive years are not immedi-

ately joined to one another and therefore conterminous, but they

are separated radially by very definite zones of fundamental

tissue of the original cortex. In each zone of growth we recog-

nize spiral and scalariform elements of a transitional form,

together with tracheids bearing bordered pits and forming the

secondary xylem. These tissue regions are disposed precisely

as inthe growth of the first year; they bear the same relations

to one another both in position and in development, and in each

case they perform the same functions as in the initial zone.

From this it follows that there is a complete regeneration of the

No. 464.] STUDE OF: TAR: SALICACEÆ 529

xylem structure in all its parts, with each year of growth, and it

is not unreasonable to consider that the same structural regions

should be designated by the same terms wherever they may

occur. In this sense, therefore, we should recognize the pri-

mary growth, as well as the secondary growth of each subse-

quent year, as composed in each case of protoxylem and

secondary xylem. The protoxylem survives throughout the

entire life of the plant.

In the higher gymnosperms as also in the Dicotyledonous

angiosperms, the case is quite different. In them the rings of

secondary growth are in all cases united to and conterminous

with the structure of the preceding year, and under these cir-

cumstances, as well as for reasons which will again be referred

to, the protoxylem experiences complete suppression and does

not reappear after the growth of the first year. In this case,

then, the primary growth consists of protoxylem and secondary

xylem, while the secondary growth consists altogether of sec-

ondary xylem, and in this we find one of the most important

structural distinctions between the Cycadacez and all other

types of gymnosperms, bringing the former into the closest

relations with their ancestral forms and removing the other

gymnosperms with the Cordaitales as the basal member of the

series, to a distinctly higher phylogenetic position.

In Cordaites, reduction has been developed to such an extent

that the protoxylem no longer forms a constituent part of the

annual rings of growth, since it is wholly confined to the growth

ring of the first year where it constitutes a region of very con-

siderable radial extent, gradually merging with the secondary

xylem in such a way that there is no sharp line of demarcation

between the two. Within this zone graduated transitions are a

"well known and remarkable feature; but it is to be noted that

in all these respects there is a further removal from the ances-

tral forms and a distinct development along those lines of evo-

lution which eventually issue in the characteristic structure of

the higher Coniferales. As these latter are reached, it is to

be observed that there is a constantly greater reduction in the

ial extent of the transition zone, and the intermediate struc-

tural variations which it presents, until, eventually, it becomes

‚530 THE AMERICAN NATURALIST. . (Vor. XXXIX.

only a few elements broad, and there is an abrupt transition

from spiral or scalariform structures to the tracheids with bor-

dered pits. We may therefore consider that in all the higher

Coniferales, the structural type is fixed to such an extent that

evolutionary aspects are no longer presented.

The changes initiated in the transition zone relate to the evo-

lution of the modified vessels or tracheids which constitute the

bulk of the structure in the vascular cylinder. In the develop-

ment of such tracheids their capacity for the movement of the

transpiration current is not lost, except in special cases, but it is

rather modified with reference to the total extent of the conduc-

tive tissue and the somewhat low rate at which the transpiration

current is required to move. Each tracheid is provided, among

the primitive forms, with bordered pits on both the radial and

tangential walls through which a somewhat ready and direct

transverse diffusion is provided for, while diffusion in a longi-

tudinal direction can never be otherwise than indirect and there-

fore at a relatively slow rate. With an advance in organization,

the bordered pits tend to disappear from the tangential walls

where they survive only at the ends of tracheids or in the sum-

mer wood, the latter distribution being necessitated by the

peculiar radial compression which such cells experience. It

follows from this that in all the higher types of the gymno-

sperms, there is a greater degree of restriction imposed upon

the transverse diffusion and through the latter, also a further

restriction of the longitudinal diffusion. Whatever deficiency in

circulation is developed through these structural alterations,

compensation is provided by the great extent to which such tis-

sue is formed ; and that the tracheids effectively discharge the

duty imposed upon them in this respect is manifested in their

complete replacement of the true vessels of the protoxylem, as

well as in the fact that those of the heart wood may resume

their functional capacity for the conveyance of nutrient fluids

when the sap wood becomes incapacitated through desiccation

or other causes (Goodwin, '88). Such restricted movement of

the transpiration current is in direct accord with the generally

xerophilous character of the gymnosperms, whether this latter

' be correlated with absolute deficiency of water supplies or a

No. 464.] STUDY OF THE SALICACEE. 531

temperature which is so reduced as to permit of but slight ab-

sorbent activity in the roots; and so it is found that the pecul-

iar form of the conductive tissue is really developed in correlation

with the environment of the plant. But it is to be observed that

the protoxylem is called upon, in the course of its development,

= to meet another essential factor in the life of the plant; namely,

its ability to withstand external stresses of various kinds and

through this the establishment of an upright position for the

organism. It is quite conceivable that this requirement might

be met by the evolution of a specialized form of element from

the meristem without reference to the prior development of

vessels, and this might be looked for in the angiosperms, but

such has certainly not been the case in the gymnosperms. The

somewhat slight modification, and in some senses the reduction

which the vessels of the protoxylem have undergone in their

adaptation to the movement of the transpiration current, has

also permitted of their immediate adaptation to the purposes of

mechanical support. They have therefore become more fibrous

in character, while at the same time their walls have become

sensibly thickened and in corresponding degrees more fully

fitted to withstand stress. It is thus evident that two forms or

directions of development have been combined in the same ele-

ment, and it is no doubt also true that the peculiar form of the

pits is in itself a direct resultant of such a combination develop-

ment, since it has been shown that the bordered pit represents

a localized area which has been left over in the otherwise gen-

eral thickening of the wall in response to the requirements of

intercellular circulation. The reduction of the bordered pit and

its frequent elimination from the wall of the tracheid, especially

in the summer wood, is in direct harmony with these statements

and represents the relative predominance of requirements relat-

ing to circulation or mechanical support at different periods of

growth and under special conditions of environment. So far as

we know at present, no further modification of the tracheid

than that presented in existing species is possible to the gymno-

sperms, and this particular line of evolution may therefore be

regarded as completed in that group.

Our hypothesis as applied to the angiosperms on analogous

532 THE AMERICAN NATURALIST: |. (Vor. XXXIX.

lines of development, is based primarily upon the idea that the

well marked differentiation of conductive and mechanical tissue

which is everywhere so prominent a feature of the arborescent

forms, extending in a less conspicuous way to herbaceous types,

cannot be secondary to and therefore derived from that special

course of development which is so fully expressed in the wood

of the gymnosperms; but that it must have had its origin in

antecedent or contemporaneous types, and that it must in conse-

quence represent a wholly distinct line of evolution arising in

response to very dissimilar environmental conditions.

In the angiosperms, representing as they unquestionably do, a

higher type of development, there is, even among their most

primitive forms, a further removal from the ancestral type, and

as presented by the Dicotyledons, they must be regarded as

essentially occupying the same general plane of development as

the higher Coniferales, inasmuch as they are all characterized

by a transition zone consisting of but few protoxylem elements ;

and the passage from these latter to the elements of the second-

ary xylem, whether vessels or wood cells, is abrupt and direct.

Like the higher Conifere, therefore, they represent types in

which the structure of the transition zone is essentially fixed,

and under normal conditions of development the formation of

the secondary xylem is, from the first, in direct response to a

fixed habit. We may nevertheless expect that under exceptional

conditions of growth such as would involve reduced vigor, and

also such as through an induced habit of growth would eliminate

very largely the special necessity for mechanical support, there

would be a more or less marked tendency in the direction of

reversion to primitive structural conditions. Such reversions

might be expected to show a distinct augmentation of the transi-

tion zone with the appearance of transitional forms of the ana-

tomical elements, which would then diverge from the protoxylem

in the particular directions imposed by the natural fixed habits

of the genus or species as the case might be. Alpine forms

of otherwise large trees might be expected to afford the most .

favorable material for the exhibition of such reversions in conse-

quence of (1) the greatly reduced form and size of the plant

consequent upon its unusual environment, and (2) the fact that

No. 464] STUDY_OF THE SALICACEE. 533

a dwarfed or even prostrate habit of growth no longer imposes

those demands for rigid support which are from the first a prime

necessity of the strictly arborescent forms. Precisely such con-

ditions and precisely such results are to be met with in Salzr

cutleri Tuckerm., of which a more detailed account will appear

on a subsequent page.

In the development of the secondary xylem of angiosperms,

two distinct lines of evolution are to be observed —the one lead-

ing to the exaggerated development of vessels, the other leading

to the exaggerated development of mechanical tissue, the two

being balanced with respect to the relative excess of require-

ments on the one side or the other. Confining our attention in

the first instance to the vessels, it is found that in their evolu-

tion from the elements of the protoxylem, these latter deviate

more widely from a fibrous form so that their products become

broader and either actually or relatively shorter, while the termi-

nal walls often disappear altogether, thus giving rise to tubular

structures of indeterminate length. The walls of such vessels

are somewhat modified by secondary thickening, though relatively

to their usually great breadth this is not more than is demanded

by their own need for support, and it cannot be regarded as an

essential factor in the strength of the organism asa whole. Like

the tracheids of the Coniferae, the walls are characterized by the

presence of bordered pits which differ in two very important

respects from the similar markings which generally characterize

the higher gymnosperms. They are always multiseriate and

chiefly hexagonal, though as shown in the Salicaceze, they may

become more distant and definitely rounded ; they also occur on

both the radial and tangential walls. In both of these features

the vessels show the survival of primitive characteristics which

are only partially represented among the Cordaitales, and which

indicate that the ancestral forms must be looked for among the

Cycadofilices where they are of well known occurrence, or else

among some other group of similar structural characteristics,

but of which we have no present knowledge. Now the angio-

sperms are essentially all broad-leaved plants adapted to a dis-

tinctly mesophytic habit, and it is therefore to be concluded that

the transpiration current not only moves with greater rapidity

534 THE AMERICAN NATURALIST. (VoL. XXXIX.

as compared with the Coniferz, but that it is of .greater volume

and requires a correspondingly more capacious channel; while

such channels must also be direct and involve fewer impediments

to free circulation in a longitudinal direction. These require-

ments are met by the large, transverse volume of the individual

vessel; by the great multiplication of vessels so characteristic of

Catalpa, Salix, Populus, etc. ; by their repetition in the secondary

xylem of each year's growth, and in the provision for very free

longitudinal movement of fiuids as expressed in the sieve-like

terminal walls, or in the complete obliteration of such interposed

septa. Although such vessels retain their capacity for the con-

veyance of the nutrient fluids for a long time, 7. e., several years,

they eventually become functionless, often through the forma-

tion of extensive thyloses as in the Catalpas, members of the

Salicacee, Quercus, etc., and in general terms the functional

capacity of the vessels cannot be restored when so lost, while

under certain circumstances, the development of thyloses may

assume a definitely pathological aspect (Watt, :01). From the

observations thus far made, it is evident that the particular evo-

lution of the protoxylem which results in the formation of such

vessels, provides elements which are solely concerned in the

movement of the transpiration current, and which have, as it

were, appropriated this function in such an exclusive sense as to

eliminate it from all other structural elements of the xylem, so

that these latter are thereby left free to develop in the most

responsive way under the special influence of other requirements.

We may now ascertain the special features which serve to dis-

tinguish the second course of evolution from the protoxylem,

already referred to. The excessive development of the conduc-

tive tissue tends to diminish the general strength and call for

the formation of purely mechanical elements to an extent other-

wise unnecessary. This factor operates, therefore, to emphasize

the divergence of the two lines of structural evolution, giving

greater prominence to the conductive elements on the one hand

as already shown, and on the other hand to the mechanical ele-

ments. Certain of the protoxylem elements, otherwise potential

vessels, are diverted in growth, and instead of expanding, they

contract with a correspondingly greater development of the sec-

ondary wall, and assume a strictly fibrous form. This necessa-

No. 464.] STUDY OF THE SALICACEE. 535

rily leads to the greater simplification of the pits which rarely

retain the bordered form but become simple perforations and

commonly disappear altogether. Concurrently with these

changes, the progressive increase in the thickness of the wall

eventually leads to a more or less complete obliteration of the

original cell cavity; and while all these varied changes have a

profound bearing upon the ultimate strength of the general

structure, they at the same time operate to eliminate completely

even such slight capacity for conduction of fluids as the elements

. may have had in their earlier stages of development.

The hypothesis as thus presented, is suggested at the present

time in view of the many facts which have come under observa-

tion during the progress of studies bearing more particularly

upon the anatomy of the Coniferales as elsewhere recorded (Pen-

hallow, :04c), and because of the need of some working basis

from which we may view the anatomy of the Salicacez, and

upon which we may erect a possible point of departure for an

interpretation of their phylogeny. The first real test of the

validity of this hypothesis will be made on the basis of data to

be derived from a study of the Salicacez as recorded in subse-

quent pages. If it proves to have the support of observed facts

it will then be necessary to supplement it with the further

hypothesis that the angiosperms as a whole had their origin

in some generalized type, possibly identical with or at least

nearly related to the Cycadofilices; and in any event we can

hardly agree with the suggestion of De Vries (:05) that the

“Monocotyledons “are obviously a reduced branch of the primi-

tive Dicotyledons," since our own investigations not only fail to

lend support to such an idea, but they tend to establish evidence

to the contrary, and to the effect that while the two may possi-

bly have had their starting point in a common, generalized type,

they nevertheless represent two distinct lines of descent. On

the basis of such a hypothesis, we should reasonably expect to

find in the early Mesozoic and Permian, and possibly even in

the later Carboniferous, transitional forms which would carry

the angiosperms back to some of the later but less highly spe-

cialized types of the Cycadofilices.

(79 be continued.)

DEVELOPMENTAL STAGES IN THE LAGENIDE.

JOSEPH A. CUSHMAN.

THE Foraminifera present certain characters which make

their study different from that of almost any other group of the

animal kingdom. They are unicellular animals, but secrete a

shell which in many cases has a considerable degree of com-

plexity and shows marked stages in development. Their geo-

logical history is very long, for representatives are found in the

Cambrian sedimentary rocks and more or less in intermédiate

horizons to the present time. At present, the F oraminifera are

found, as a rule, in the deep waters of the oceans and extending

toward the shores. Some twenty or more of the species occur

as pelagic forms. In these animals the intermediate steps

between extreme generic and specific forms are so well filled

in, even in the living species, that some authors have regarded

them all as simply variations of a single species. This is

altogether too extreme a view. Intermediate species may be

expected when the habits, environment, and reproductive char-

acters of the animals are taken into consideration.

That the laws of development enunciated by Professor

Alpheus Hyatt may be applied to this group, is shown in the

following discussion. These laws have hitherto been applied

only to groups of the Metazoa but as will be shown in the

present paper they are equally applicable to another group of

the animal kingdom, the Protozoa. :

In tracing the development of Foraminifera where young

individuals can be obtained, the relations are usually made out

with ease. In the absence of young individuals the most reli-

able method is the study of sectioned specimens, since many

species which are coiled, cover all traces of the younger portion

externally by their later growth. Sectioning, in many cases, is

the only method by which, from adults, the characters of the

early growth may be seen in their true relations.

7 537

538 THE AMERICAN NATURALIST. [Vor. XXXIX.

DEFINITION OF A FEW TERMS.

The following terms as defined, some of which are new, are

convenient in the description of the structure of the shell of For-

aminifera. The suc-

ceeding divisions of the a

shellare usually spoken

of as chambers, the one

first formed being the

initial chamber (/ in

Figs. ı and 2) and the

last one built in any

given specimen, the

anterior chamber (4).

The initial chamber

which will be shown

to have a decidedly

phylogenetic bearing in

the group is here given

a distinctive name —

the proloculum—to cor- 2

respond with the term F's- :— Nodosara. Fic. 2 — Uncoiled form of Cristel-

applied to the embry- Mode: d. anterior en posterior end. Arrows

onic shell of oth er show the direction of growth ; shaded portions indicate

the angle of at C, C,/ C" ; S, sutures.

groups already worked

out in the Metazoa. The ends of the shell as a whole are called

anterior (2) and posterior ( P) The walls of the chambers are

called anterior and posterior walls according to their individual

position in relation to the direction of growth. The line of

contact made by the joining of a succeeding to a preceding

chamber is called a suture (5). In coiled forms the outer bor-

der formed by the sum of the distal portion of the walls of suc-

ceeding chambers is called the peripheral margin. The angle

between the suture and the distal wall of the next succeeding

chamber in coiled forms is called the angle of curvature for that

portion of the peripheral margin. These angles are shaded at

C, C', C", to show the decided differences that the angle may

assume.

No. 464.) STAGES IN LAGENIDA. 539

DEVELOPMENT OF TYPICAL SPECIES OF VARIOUS GENERA.

Lagena.— This genus represents the simplest condition seen

in the family under discussion. In its geological history it can

be traced from the Silurian to the present time. It is mono-

thalamous or single-cham-

bered (Fig. 3) . Ihe

species very commonly

develops a neck at the

anterior end (Figs. 4, 5).

The variation in forms

of ornamentation is very

remarkable and includes

costae, reticulate patterns,

knobs, and bosses or

broadly expanded wings

of shelly material, but the

underlying character of

the chamber is always

that of a simple flask-like |

form or a modification of

it. This simple chamber

1 5 represents the completed

eye development of this ge-

group. Fig. 3, Lagena globulosa Montagu, asmooth nus, which is the only

type; Fig. 4, Z. salcata W.& J., var. interrupta £

Williamson, a costate type; Fig. 5, Z. fi one of the family that

pee Atc Mas the single-chambered

character. As it is the

simplest form in the family and as all the other genera of the

family start off with a simple chamber which is comparable to

it, Lagena may be taken as the radical from which other genera

of the family may be derived.

Nodosaria.— This genus in its typical form consists of a linear

series of Lagena-like chambers, the posterior wall of each newly

added chamber overlapping the anterior wall of the preceding

one. The initial chamber or proloculum is comparable in char-

acter to the adult Lagena but the addition of the second cham-

ber in Nodosaria shows that it is developing beyond the single-

or Mosa

540 THE AMERICAN NATURALIST. (Vor. XXXIX.

chambered Lagena condition. The succeeding chambers add

no striking characters in development further than that given by

the second except in features of ornamentation which is a sec-

ondary character. The chambers of the linear series may be

more or less closely overlapping (Figs. 6, 7) and this character

6 8

Fics. 6-8.— Three species of Nodosaria showing the difference in the amount of

overlapping, and in Fig. 8 the Lagena-like last chamber. Fig. 6, Nodosaria

Ayrula d'Orb.; Fig. 7, N. radicula Linn.; Fig. 8, N. scalaris Patsch (Figures

after Brady.)

of overlapping may vary with the age of the individual as shown

in progressively added chambers of Nodosaria scalaris var.

seperans Brady (Fig. 8). They may also be variously orna-

mented according to the species but the linear series of cham-

bers is always the essential character. Very often the last-

formed or final chamber is more distinctly separated from the

preceding ones and is decidedly Lagena-like (Fig. 8). There-

fore at the end of growth representing old age or senescence, a

chamber may occur which is closely comparable to the first

stage of development in the young of the same individual or to

the simpler genus Lagena. The stages of development of

Nodosaria from young to old age may be expressed by a form-

ula using the initial letters of the genera represented, as

LINE

No. 464.] STAGES IN LAGENIDE 541

Cristellaria.— The initial chamber or proloculum of Cristel-

laria, as in the other genera of the family, is simple and Lagena-

like (Pl. 1, Fig. 6). The second chamber is added obliquely

(Pl. ı, Fig. 7), as in some species of Nodosaria, and at this

stage simply reveals the fact that it will not be a Lagena nor

any of the straight Nodosarian forms. The third chamber of

Cristellaria adds a decidedly new character. Instead of con-

tinuing on as in Nodosaria, it extends back on its inner margin

so as to come in contact with the proloculum or initial chamber

initiating the feature of coiling (Pl. 1, Fig. 8). In Cristel'aria

this coiled character is maintained throughout further growth

in typical species as in Figs. 9, 18, 19. In further growth the

shell may take on a flattened form as in Crzstellaria compressa

d'Orb. or may later take on a loose-coiled, or straight form

of growth as in the species C. szddalliana Brady (Fig. 21) and

C. tenuis Bornemann (Fig. 12) which are at present included

in the genus. The typical Cristellaria is marked by the coiled

form as the acme of its development (Figs. 18, 19), with a result-

ing close-coiled form throughout its life history beginning with

the third nepionic chamber.

As with Nodosaria, a formula may be made to represent the

stages in development. In Cristellaria it is the third chamber

which is the determinative one, and the formula for the close-

coiled form (Fig. 18) would be, Cristellaria = L+N +C. The

absence of repetition of any letter in the formula indicates

progressive development as a coiled form, as no senescence is

seen in the form or arrangement of the chambers in typical spe-

cies which are close coiled in the adult.

Cristellaria as at present recognized contains species showing

excellent differences in the degree of acceleration of develop-

ment. In such species as C. articulata Reuss (Fig. 9), the ciose-

coiled character after being taken on, extends throughout the

succeeding life history. In others, as C. siddalliana Brady (Fig.

10), the main part of the shell is close-coiled but towards the end

of its growth there is an uncoiling seen in the last three cham-

bers of this specimen. This is brought about by the failure of

chamber 21 to extend back to the preceding coil and the con-

tinued shrinking away of the next-formed chambers, 22 and 23.

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PLATE. i.

he figures given show the ontogeny of aeg genera of zn wre to hee

comparative stages in "development. 1, Lagena, the primitive radical ;

Marginulina; 6-9, Cristellaria; 10-13, eis a; 14-17, Pol ynorphia ; Gb, Dimor phina ; the

embryo nic s stage, the ee is represented i in ae quus row and may be — to Lagena

above, may be compared to Nodo-

su pr row the true generic earache are definitely el on at

sara. [n the neanic recs in

least as regards progressive charact

544 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

In uncoiling as is shown in Fig. 2, there is a decided change in

the angle of curvature from an acute angle gradually to an

obtuse one. This seems to be the rule in the stages by which a

straight growth is produced from a coiled one as is shown again

in Figs. 11 and 12. In C. schlenbachi Reuss (Fig. 11), the

uncoiled character is early taken on until on an average only the

first six to eight chambers are coiled, while the succeeding cham-

bers which constitute the major part of the whole growth, are

Fics 9-12.— Four species of Cristellaria, showing different degrees in the acceleration of the

character of uncoiling. Blackened chambers show the extent of th escent uncoiled

Fig. 9, Cristellaria articulata R ady; Fig. 11

C. schlenbachi Reuss; Fig. 12, C. tezzuis B

ortion.

portion uss; Fi

euss; Fig. ro, y;

ornemann. (Figures adapted from Brady.)

uncoiled. Thus the senescent character of uncoiling in this last

species is more accelerated in its development than in C. s¢ddal-

ana as it originates much earlier in the onto

of the individual.

(Fig. 12)

chambers,

geny or life history

In such a species as C. tenuis Bornemann

the coiled portion is usually limited to the first four

| while the last fifteen or more are uncoiled. Other

specimens of this species show fewer chambers than that fig-

ured. This speeies is then, even more accelerated in develop-

ment, for the senescent Character is so accelerated that it

includes four fifths of the entire number of chambers. In the

complete return to the strai |

Sht Nodosarian growth, as shown in

the last few ch

ambers of this Species, there is a return to a right

No. 464.) STAGES IN LAGENIDE 545

angle in the angle of curvature if it may be so called. In the

entire development from the right-angled condition in the Nodo-

sarian young, there is a change gradually to an acute, then a

right, next an obtuse, and finally back to the right angle again.

This then represents the mechanics of the uncoiling. The char-

acter of uncoiling in these four species of Cristellaria is repre-

sented in Figs. 9-12, in which the black chambers represent the

portion showing senescent uncoiling. The white portion shows

the extent of the coiled development.

Marginulina.— The first three chambers in the specimen of

Marginulina figured (Pl. ı, Fig. 4), are exactly comparable to

the same chambers of Cristellaria (Pl. 1, Fig. 8). The first

chamber is Lagena-like, the addition of the second gives the

oblique Nodosarian form, and the third is seen to be truly

Cristellarian. The formula thus far would be as in the pre-

ceding, L+N+C. The fourth and fifth chambers in this spec-

imen of Marginulina, however, present a new feature; they fail

to extend back to the initial

one, but strike off at a tangent

showing the incipient stage of

uncoiling. The chambers as

built, continuing in the line

or direction initiated by the

fourth chamber, form a Nodo-

sarian growth and the adult

therefore may be represented

by the formula, Marginulina

mis + N+ C +N... Thisis

shown in Fig. 14 in section,

and in Fig. 13 from the ex-

Fic, i Marginulina ensis Reuss, showing terior.

the main portion of the growth uncoiled. In certain cases in old age

Mud d m roh median line of the last-formed chamber is

less closely overlapping than

the preceding and therefore takes on a form very much like

Lagena. In Marginulina, representing this last chamber in the

formula we have, Marginulina = L+N+C+N+L. This shows

a complete cycle of stages seen in progressive and typical sen-

546 THE AMERICAN NATURALIST. [Vor. XXXIX.

escent or regressive development. Such forms as that figured

and the majority of species usually classed under Marginulina

are not intermediate between Nodosaria and Cristellaria as is

commonly stated,- but are truly senescent species derived from

Cristellaria and resulting from acceleration of development and

the shoving back of the Cristellarian character to the early

stages in development.

Polymorphina.—The proloculum or initial chamber in Polymor-

phina as shown in Fig. 15, is here also simple, like Lagena, as in

the previous genera. The second chamber (Pl. ı, Fig. 15) is

added in the same manner as in Nodo-

saria and in the second stage in all its :

visible characters Polymorphina appar-

ently belongs to that genus. The addi-

tion of the third chamber (Pl. ı, Fig. 16)

initiates a new character in the line of

development. It continues back over

the preceding one to the proloculum as

in Cristellaria but is added in a differ-

ent manner being so placed that the

aperture faces the line of the median

Fic. ı5.— Section through

axis. This generic character may be median plane of Polymor-

represented by P and the formula for y amemus €

the genus may be expressed as follows :

Polymorphina = L + N + P. The fourth chamber also extends

back to the initial chamber (Pl. 1, Fig. 17) but is added on the

opposite side from the third with its aperture facing and

occluding that of the third, and this character continues

throughout further growth to the adult. This is then a pro-

gressive form and after its Nodosarian second stage, starts a

new line of development which at once places it in a different

group from Cristellaria and Marginulina.

Dimorphina. — In this genus the early stages up to the fourth

chamber (Pl. ı, Fig. 20,) are exactly as in Polymorphina and

may be represented by the same formula, L -- N +P. If the

animal had died at this stage it would be described as Poly-

morphina. After this stage, however, a quite different mode

of growth is assumed. Beginning with the fifth chamber, suc-

No. 464.] STAGES IN LAGENIDE. 547

ceeding chambers are arranged in a linear series and are there-

fore Nodosarian in character. The formula for the adult would

be, Dimorphina = L+ N 4- P-- N. Thelast chamber is often

more or less free and like Lagena. The formula for the com-

pleted growth including this gerontic character will then be,

Dimorphina = L 4- N - P --N +L. Dimorphina is therefore

a senescent genus having as its basis the three progressive char-

acters of Polymorphina and in senescence has, by retracing in

inverse order, attained in the last chamber to a condition com-

parable to that seen in the proloculum, or in other words to

Lagena. Having completed the cycle, such forms evidently

have attained completion along certain lines of development

and no new forms can originate from this senescent type except

in regard to minor changes in character of ornamentation which

are recognized as specific and not generic in value.

SENESCENT CHARACTERS.

Characters showing typical senescence are frequent among

the Foraminifera and illustrate in simple terms conditions simi-

lar to those found in many other groups of the animal kingdom.

The simplest of these senescent characters is the loss of orna-

mentation. The ornamentation of this group is shown mainly

by elevated ridges, by tubercles, or by spines. Examples of the

loss of these will be given. As found by Hyatt in Cephalopoda,

the uncoiling of forms, which in their early development were

close-coiled, is a decided feature of senescence. Such cases are

seen in their simplest terms among the Foraminifera. As

shown by Beecher, one of the characters apt to appear in the

decline of a group is a peculiar spinose or extravagant growth,

“wild” growth, as it is sometimes called in the Foraminifera.

Certain senescent genera of Foraminifera show this character

exceptionally well. One of the surest indications of senescence

is a return to the simpler conditions seen in the young of the

ual and in the adults of more primitive forms. Ex-

same time very simple cases of this are seen

The Foraminifera as uni-

same individ

cellent and at the

in Dimorphina and in Dentalinopsis.

548 THE AMERICAN NATURALIST. [Vor. XXXIX.

cellular organisms seem to present the simplest conditions and

examples for the expression of the various laws of development

that can be found anywhere in the animal kingdom.

Loss OF ORNAMENTATION.

Ridges. —In a specimen of Uvigerina angulosa Williamson,

var. spinipes Brady (Fig. 16), the e chambers have definite

raised coste or ridges run-

ning generally parallel to the

axis of the growth of the

shell. In later growth this

character becomes less pro-

nounced and in the last five

chambers which by measure-

ment represent more than

half of the growth, is entire-

ly wanting, and the cham-

bers are perfectly smooth.

Although not included in

this family, Bulimina sub-

ornata Brady is figured here FtS- :6— Uvigerina angulosa Williamson, var.

(ur a f ak viij Brady, showing loss of ornamentation

parison shows n senesce

in much the same manner Fis. 7 Blinn seid Pe een

(Fig. 17) the costate early

growth and the gradual disappearance and final loss of costation

in the old age of the individual.

Tubercles.—ln Cristellaria echinata d'Orb. (Fig. 18), the early

growth is marked by rows of bead-like tubercles over the sut-

ures, while the intermediate space is covered with hemispherical

granules. In later growth these scattered granules are limited

to the peripheral portion and on the last two chambers are

entirely wanting, so that the surface of these chambers is

smooth. The rows of bead-like tubercles also disappear in old

age and pass into a smooth ridge. Similar conditions are

found in various groups of the Mollusca, especially in certain of

the fossil Trigonias. In such forms the costae break up into

knobs and bosses in development, and later in the old age of

No. 464.] STAGES IN LAGENIDE 549

the individual again resume a costate condition by the merging

together of the tubercles.

Spines. — In the preceding species, C. echinata d'Orb. (Fig.

18), the loss of spines is a very evident character in senescence.

Fic. (srcholl, b ta d'Orh h 3 1 $

Fıc. = C. carcass ing f spi

FIG. 20 leata d'Orb., showing similar loss of spines (After Brady.)

In the median portion of growth the peripheral spines at the

sutures are long, at least equalling the length of the chamber

on the peripheral margin. The third from the last is shorter

and the last two spines decrease progressively in size, the last

one being very short, while at the last suture no spine at all is

developed. Much the same condition of affairs in regard to the

reduction and loss of spines is seen in C. calcar Linn. (Fig. 19),

in which, however, the spines do not coincide with the suture

lines. Another excellent example, although not in the same

family, is that presented by Bulimina aculeata d'Orb. (Fig. 20).

Here the early growth is marked by well developed spines. As

growth progresses, the spines of successively added chambers

are not so greatly developed. Toward the later growth, traces

of them are seen in the very reduced spines at the posterior

angles and on the last-formed chambers they are lacking, and

the chambers are perfectly smooth.

These examples of loss of ornamentation as a character in

senescence are exactly comparable to cases already worked out

550 THE AMERICAN NATURALIST. (VoL. XXXIX.

by others in the Cephalopoda, Pelecypoda, Gastropoda, and

Brachiopoda and they are seen in still other groups.

Uncoiling.— Cristellaria siddalliana Brady (Fig. 21) shows

an excellent case of uncoiling not carried to an extreme. The

FIG. 21.— Cristellaria siddalliana Brady, showing uncoiling in last few chambers.

FIG. 22.— Trochammina lituiformis Brady, showing uncoiling carried to an extreme.

early chambers are close-coiled and this feature continues until

the last few chambers. Here there is a distinct change and

an uncoiled form is produced as shown in the figure. This

uncoiling is only seen in well advanced specimens that show old

age characters. Other examples of uncoiling in Cristellaria

have already been given (Figs. 11, 12). Although outside of

this family, Trochammina lituiformis Brady is figured (Fig. 22)

to show the character of uncoiling carried to an extreme. The

early chambers make a little more than a single volution, while

the succeeding growth is uncoiled. In old age specimens, this

character may be carried to a greater extent than is shown in

Fig. 22. In this species in contrast to the preceding, the

majority of the chambers. form the uncoiled portion of the shell.

Such examples are exactly comparable to Baculites or Lituites

No. 464.] STAGES IN LAGENIDE 551

among the Cephalopoda or to Vermetus or Magilus among the

Gastropoda. .

Spinose or ** Wild” Growths.— In Polymorphina and Sagrina

of this family the last chambers are often peculiarly different

from the preceding ones. In Polymorphina orbignyit, as figured

by Brady, Parker, and Jones (Trans. Linn. Soc. London, vol.

27, p. 244, pl. 42, fig. 38c) the last chamber is marked by a

eculiar fistulose growth, greatly differing from the preceding

regular chambers of the species (Fig. 23). Such growths are

L ig mn with peculia fi 1 g +h in senescence

Pata d'Orb. with “wild ” growth. (After Brady.)

Fic. 23.— Poly ‘p

n c.

FIG. 24

not infrequent in various other genera. Corresponding “ wild”

growths appear in certain species of Cristellaria. In Umgerina

aculeata d’Orb. (Fig. 24) similar characters appear. This spe-

cies in its younger development has simple longitudinal costae.

Later, however, there is a thickening by addition from the out-

side and the last chamber is covered with a decidedly spinose

development totally different from the previous ornamentation.

This spinosity may continue, extending progressively posteriorly

until it envelops the whole shell, covers the preceding cham-

bers, and hides all traces of the typical earlier ornamentation.

These growths seem to be best regarded as senescent charac-

552 THE AMERICAN NATURALIST. (VoL: XXXIX.

ters. Such a decided change in method of growth, with an

increase in the thickness of the shell without corresponding

increase in the number of chambers, may be compared in a

general way to the building up of tissue in the old age of

Brachiopoda and Mollusca where there is no increase in size

of the living chamber but frequently a decrease. It may be

more closely compared to similar conditions which appear in

the Gastropoda for example in the several Eocene species of

Calyptraphorus where by reflection of the mantle in later

growth a callous develops which hides the previous sculpturing.

RETURN TO SIMPLER CONDITIONS.

Dimorphina.— In this genus, the development of which has

already been noted, there is a return to a straight uniserial

growth in the later chambers. This was expressed by the

formula E-NFPINIL Ik is a true return to the Nodo-

sarian and Lagena characters seen in the progressive develop-

ment of the first two chambers. The biserial Polymorphine

character in Dimorphina is accelerated so that it may appear

in but two chambers including the third and fourth

and a return to the uniserial condition is then taken

on in the fifth. This return to the simpler Nodo-

sarian condition, seen in the young of the same in-

dividual and again as the acme of development in an

ancestral type, Nodosaria, can be regarded only asa

truly senescent character and the genus Dimorphina

a senescent one derived from Polymorphina.

Dentalinopsis — In this genus (Fig. 25), the early

: chambers are uniserial like those of Nodosaria. At

iih ues Bst they are circular in cross section but soon

Vidi Tm become triangular or polygonal. At this point the

» inge s Species which have this character as their highest

last-formeg development are classed under the genus Rhab-

= (After dogonium which is characterized by angular sec-

tion in the adult. The formula for Rhabdogonium

would be L+N4R

No. 464.] STAGES IN LAGENIDA 553

Senescent forms have been found among the fossils and to

such forms Reuss has applied the generic name Dentalinopsis.

In species of this genus the later growth instead of being tri-

angular reverts to its earlier circular cross section and becomes

truly Nodosarian. Reuss noted the generic value of this senes-

cent character, although his genus has not always been recog-

nized by later writers. The last-formed chamber may be more

free and distinctly Lagena-like, thus completing the reversion

in senescence. The formula for a specimen which has the

Lagena-like last chamber would be L + N+R+N+L,

showing its definite regressive senescence.

. STUDIES ON THE PLANT CELL. — VI.

BRADLEY MOORE DAVIS.

SECTION V. CELL ACTIVITIES AT CRITICAL PERIODS OF

ONTOGENY IN PLANTS (Continued).

5. APOGAMY.

APocAMY is the suppression of the sexual act and the devel-

opment of a succeeding generation asexually. The term was

first proposed by De Bary in 1878, following Farlow's (74)

discovery of the phenomenon in Pteris cretica. The succeeding

generation may arise in one of two ways: (1) by the develop-

ment of an unfertilized egg or gamete which is termed partheno-

genesis, or (2) by some form of vegetative outgrowth from the

sexual plant, a process which has been called vegetative apogamy.

We shall not attempt to give a detailed account of apogamy in

the plant kingdom but will confine ourselves chiefly to the con-

sideration of a few detailed studies of recent months which have

taken up the cell problems concerned. The cell problems nat-

urally treat of the processes which may be substituted for the ~

sexual act in ontogeny and the fundamental problems of the

behavior of the chromosomes under these conditions.

. Parthenogenesis has been known for many years among the

thallophytes which furnish illustrations in a variety of groups.

In the algæ we have the well known examples of Chara crintta,

Cutlaria, Dictyota, some species of Spirogyra and Zygnema, and

a number of types in the lower Chlorophycez and Phæophyceæ

whose motile gametes will germinate like zoóspores should they

fail to conjugate with one another. The recent studies of Wil-

liams (:04b) on Dictyota give the only observations which have

been made on nuclear activities during the parthenogenetic

development of eggs in any algal form and will be considered

presently. The fungi furnish beautiful illustrations of partheno-

555

556 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

genesis in the Saprolegniales. Trow (:04) believes that some

of these forms are sexual but there can be little doubt that the

group as a whole is generally apogamous. There is probably

much apogamy in the Ascomycetes and an almost entire suppres-

sion of sexual organs in the Basidiomycetes but no clear instance

of parthenogenesis (č. e., a development from a cell whose mor-

phology is unquestionably that of an egg) is known in either of

these groups.

Parthenogenesis is not known in the bryophytes and pterido-

phytes excepting for Marsilia (Shaw, '97 ; Nathansohn, :00).

Although there is much apogamy in the pteridophytes, especially

in the leptosporangiate Filicales, the new generation generally

develops as a bud-like outgrowth on the prothallus (vegetative

apogamy). There have been no nuclear studies on the parthen-

ogenetic Marsilia but an interesting preliminary account has

'appeared announcing nuclear fusions in the apogamous develop-

ment of Nephrodium (Farmer, Moore, and Digby, :03).

Parthenogenesis is now known in the spermatophytes for

Antennaria alpina (Juel, '98, : 00), several species of Alchemilla

(Murbeck, :o1a, : orb, : 02 ; Strasburger, :04c), Thalictrum pur-

purascens (Overton, :02, :04), Gnetum (Lotsy, :03), a number

of forms of Taraxacum (Raunkiaer, :03; Murbeck, :04), sev-

eral species of Hieracium (Ostenfeld, : 04a, : o4b ; Murbeck, : 04),

Wikstremia indica (Winkler, :05), and is suspected for Ficus

Treub, :02) and Bryonia dioica (Bitter, :04). A number of

cases of polyembryony were formerly considered examples of

apogamy but are now known to be developments from the nucel-

lus and consequently vegetative buds of sporophytic origin and

entirely independent of gametophytic activities. The best known

of these forms are Funkia, Ccelebogyne, Citrus, Opuntia, and

Alchemilla pastoralis. Vegetative apogamy is illustrated in the

development of embryos from antipodal cells as in A//ium odorum

(Tretjakow, '95 ; Hegelmaier, '97) or from the cells of the endo-

sperm as in Belanophora (Treub, ’98 ; Lotsy, 99). Synergids

have been reported to form embryos in a number of forms but

many of these have proved to be cases in which the synergid is

fertilized by a sperm nucleus and not examples of apogamy.

However, synergids are known to develop embryos apogamously

No. 464] STUDIES ON PLANT CELL.—VIT. 557

(or parthenogenetically if the antipodal be considered the homo-

logue of an egg) in Alchemilla sericata (Murbeck, :02). A sum-

mary of the various types of vegetative apogamy, parthenogen-

esis, and sporophytic (nucellar) budding, supplementing a list of

Ernst (:or) is given by Coulter and Chamberlain (: 03, p. 221).

We will now take up the few investigations which consider

the cytological details of parthenogenesis. That of Williams

(: 04b) on Dictyota is the only one treating of a lower type. It

seems probable that parthenogenesis in Dictyota is in no sense

normal and would not lead to mature plants, since the germina-

tion of unfertilized eggs in the cultures of Williams presented

many irregularities.. The spindles instead of being formed from

asters with centrosomes are intranuclear in origin, multipolar,

and very irregular in their form. As a result the 16 chromo-

somes become scattered and a cluster of daughter nuclei is

formed containing varying numbers of chromosomes, sometimes

one and sometimes several. It is clear in Dictyota that the fer-

tilization of the egg results in the development of an aster with

a centrosome which exerts a directive influence in mitosis pre-

venting a scattering of the 32 chromosomes and conducting the

mitosisin a normal fashion. Williams does not believe that the

centrosome is introduced as an organized structure into the egg

by the sperm but that it is formed de novo as a result of the

increased metabolic activities present in the fusion nucleus as

compared with that of the unfertilized egg.

There have been several important studies on parthenogenesis

in the spermatophytes. Some of these papers while establishing

the facts of parthenogenesis in various forms, give no details of

nuclear history or behavior of the chromosomes. But the studies

of Juel (: 00), Overton (:04), and Strasburger (: 04), present some

very interesting data on the cytological features of parthenogen-

esis in Antennaria alpina, Thalictrum purpurascens, and several

species of Alchemilla.

Several recent papers indicate that parthenogenesis may prove

to be general in certain genera or even €

groups and therefore a far more widespread phenomenon than

has been supposed. Raunkiaer (: 03) (abstract in English in

Bot. Centralb., vol. 93, p. 81, 1903) proved by cutting off the

558 THE AMERICAN NATURALIST. (VoL. XXXIX.

tops of young flowers that several species of Taraxacum pro-

duced normal seeds apogamously and concluded that the embryo

must develop parthenogenetically since Schwere, in 1896, traced

its origin from the egg. Ostenfeld (:04a, : 04b) from failure to

find pollen on the stigma of Hieracium and failure to make it

germinate in a number of solutions, was led to try similar experi-

ments to those of Raunkiaer in cutting off the anthers and stig-

mas of flowers. He found that a large number of species of

Hieracium were able to set seed apogamously and he believed

parthenogenetically but histological investigations were not made

to establish the last point. The experiments of Raunkiaer and

Ostenfeld are interesting as showing how a form by virtue of its

parthenogenetic habits might become segregated and quite re-

moved from the probability of hybridization. Murbeck (: 04) in

a short paper announced that the embryos in Taraxacum and

Hieracium, developing from flowers whose stamens were cut out

(as in the experiments of Raunkiaer and Ostenfeld) actually do

develop from the egg cell and are therefore parthenogenetic.

Murbeck also failed to find pollen tubes in the ovules where

pollen had been applied to the stigma. Winkler (104) reports

that Wikstremia indica matures very little perfect pollen and

produces its seeds apogamously, as proved by experiment. The

embryos are stated to develop parthenogenetically from the egg

but no details are given in this preliminary paper of the chromo-

some history. This group of contributions while very interest-

ing, presents no data on the fundamental problems in a cyto-

logical explanation of parthenogenesis.

Murbeck (:01a) concluded for Alchemilla that true tetrads

were formed previous to the differentiation of the embryo-sac

but nevertheless found evidence that there were no reduction

phenomena so that the nuclei within the embryo-sac contain the

sporophytic number of chromosomes. Murbeck’s evidence of

tetrad formation was not satisfactory and in the light of recent

studies of Strasburger (:04c) cannot be accepted. His view

was, however, correct that there is no reduction of the chromo-

somes in the formation of such embryo-sacs as produced par-

thenogenetic embryos.

Juel (:00) gives a critical comparison of the development of

No. 464.) STUDIES ON PLANT CELL.— VII. 559

the embryo-sac in the parthenogenetic Antennaria alpina with

A. dioica whose ovules are normally fertilized. In A. dioica the

embryo-sac is one of a group of four cells (tetrad) which are

formed through two successive mitoses (heterotypic and homo-

typic) showing the characteristic features of sporogenesis. A

clear stage of synapsis precedes the first mitosis. The type of

embryo-sac development in this form is then entirely normal.

Not only are tetrads suppressed in the parthenogenetic Anten-

naria alpina but there is no trace of the heterotypic and homo-

typic mitoses in the embryo-sac. The number of chromosomes

is very large (about fifty) and evidently the same as is found in

other periods of the life history. There is then no reduction of

the chromosomes during the formation of the embryo-sac in the

parthenogenetic species and the egg and other nuclei in this

structure have consequently the sporophytic number. There is

no need of fertilization to bring the egg to a condition when with

respect to chromosomes it is prepared to develop a sporophyte

embryo. Juel (:04) notes certain peculiarities in the develop-

ment of the embryo-sac of Taraxacum officinale. Tetrad forma-

tion is reduced to a single mitosis and this is not heterotypic,

since there seems to be no reduction of the chromosomes.

Details are not given.

Overton (: 04) finds normal reduction phenomena in the pol-

len mother-cell of Thalictrum purpurascens which establishes the

number of chromosomes to be 24 for the sporophyte and 12 for

the gametophyte generations. These mitoses are thoroughly

typical of sporogenesis being preceded by a synapsis stage.

The development of the embryo-sac is of two types. In some

cases a tetrad of four megaspores is formed from a megaspore

mother-cell. The nucleus of this cell passes through a synapsis

and the first mitosis is heterotypic showing the reduced number

of chromosomes. The lower cell of the tetrad becomes the

embryo-sac. But many embryo-sacs pass through a different

history. There is no heterotypic mitosis and no reduction of

the chromosomes which remain 24 in number. Thus in some

ovules the mitoses of sporogenesis are omitted and true tetrads

are not formed, with the result that the embryo-sac contains

nuclei with the sporophyte number of chromosomes (24) in

560 THE AMERICAN NATURALIST. [VoL. XXXIX.

place of the gametophyte (12). The details of the nuclear

history in these embryo-sacs have not been followed but it is

plain that their eggs have the requisite number of chromosomes

to develop sporophyte embryos parthenogenetically. The vary-

ing proportions of parthenogenetically developed seeds which

may be found on plants of 7halictrum purpurascens indicate that

the suppression of normally developed embryo-sacs is not very

firmly established in this form.

We now come to a recent paper of Strasburger (: 04c) which

is the most important contribution to the subject of partheno-

genesis that has yet appeared. Strasburger studied a number

of species of Alchemilla from the section Eualchemilla, the

group which formed the subject of Murbeck's important discov-

eries. Most of the forms develop pollen in a normal manner

and Strasburger was able to follow reduction phenomena in this

process without difficulty. The nucleus of the pollen mother-

cell passes through a synapsis followed by a heterotypic mitosis

in which the structure of the chromosomes as bivalent elements

is apparent. The bivalent chromosomes are in the reduced

(gametophytic) number. Similarly Strasburger found that some

species (e. g, Alchemilla pentaphylla, gelida, and grossidens)

formed embryo-sacs in a normal manner with the presence of a

tetrad and a characteristic reduction division (heterotypic). But

the development of the embryo-sac in apogamous species (e. g.,

Alchemilla speciosa, splendens, and fallax) cuts out the two

mitoses of sporogenesis and no tetrads are formed. The nucleus

of the megaspore mother-cell emerges from synapsis with the

sporophyte number of chromosomes and the first division which

follows is a typical mitosis and not heterotypic. The embryo-sac

then comes to contain a group of nuclei with the sporophytic

number of chromosomes in place of the gametophytic and a

parthenogenetic development of the egg takes place. Stras-

burger regards the parthenogenetic tendencies of Eualchemilla

as associated with excessive mutations among these forms through

which sexual processes are becoming displaced by apogamous

methods of reproduction. :

This clear evidence that the cause of parthenogenesis in |

Antennaria, Thalictrum, and Alchemilla lies in the suppression

No. 464.] STUDIES ON PLANT CELL.— VII. 561

of chromosome reduction during the formation of the embryo-

sac seems to offer an explanation of other examples of apogamy

presented by the embryo-sac. Thus apogamous developments

of embryos from synergids as in Alchemilla sericata (Murbeck,

:02) or from antipodals as in 4/um odorum wil not seem

strange if reduction processes are suppressed in the production

of an embryo-sac and its nuclei retain the sporophyte number of

chromosomes. Such nuclei have in them the same potentialities

of development as do those of the nucellus whose cells form

embryos vegetatively and entirely independent of gametophytic

activities in a number of forms (e. g., Funkia, Calebogyne,

Citrus, Opuntia, Alchemilla pastoralis, etc.). This type of

apogamy from a gametophyte which retains the sporophyte

number of chromosomes may be found to hold a very close

relation to apospory for there is the same reduction or omission

of the processes of sporogenesis as is found in that phenome-

non. However, since we know nothing of the cytological events

of apospory it is unwise at present to follow the speculation

further.

The peculiarities of parthenogenesis in the spermatophytes do

not seem so remarkable since the discoveries recorded above. It

is not strange that an egg should form an embryo without fer-

tilization when: its nucleus contains the sporophyte number of

chromosomes. The most remarkable feature in this suppression

of reduction phenomena in Antennaria, Thalictrum, and Alche-

milla is the- possibility of developing an embryo-sac with nuclei

in the number and arrangement typical of the female gameto-

phyte and yet with the sporophyte count of chromosomes. The

embryo-sacs with their contents have clearly the morphology of

female gametophytes and must be so considered in spite of the

fact that their nuclei contain twice as many chromosomes as

usual. It is clear that the potentialities of sporophyte and

gametophyte involve other factors besides those of the chromo-

some count. This isa very important conclusion because we

have been accustomed to lay great weight on the number of

chromosomes as the cause of sporophytic and gametophytic

developments respectively. We must recognize the presence of

other factors determining alternation of generations besides the

chromosomes.

562 THE AMERICAN NATURALIST. (VoL. XXXIX,

There are two types of parthenogenesis in plants : (1) thatin

the thallophytes where there is no sporophytic generation, and

(2) that in higher forms when the life history is complicated by

an alternation of generation. We know nothing of the cytologi-

cal conditions in the first group including such types as Chara

crinita, Cutlaria, some species of Spirogyra and Zygnema and

numbers of the lower Chlorophycex and Phzophycez whose

motile gametes will germinate like zoóspores should they fail to

conjugate with one another. But since there is no reason to

suppose that there are reduction phenomena at gametogenesis,

the unfertilized gamete is fully prepared with respect to the

number of chromosomes to continue the parent stock. Dictyota

must be excluded from this list since the parthenogenetic devel-

opments here are abortive. In the second group parthenogene-

sis is likely to prove to be the result of a suppression of reduction

processes during sporogenesis by which a gametophyte genera-

tion retains the sporophyte number of chromosomes and in

consequence is prepared to dispense with sexual processes in the

development of a new sporophyte. Parthenogenetic develop-

ment in animals seems to be similar in its essential cytological

features to parthenogenesis and apogamy in plants. There may

be a suppression of reduction processes somewhat comparable to

that discussed above, which takes place, however, at the time of

gametogenesis, whereby the egg nucleus retains the number of

chromosomes characteristic of the parent. Or, through a fusion

with the nucleus of the second polar body the egg nucleus is

brought back to the normal condition with respect to the num-

ber of chromosomes of the parent stock. We cannot, however,

consider in detail the forms of parthenogenesis in animals. They

have been recently treated by Blackman (:04b) in comparison

with conditions in plants.

Apogamous developments which involve wholly or in part

other elements than gamete cells and nuclei are likely to be

established in a number of groups of the thallophytes. The

author has long believed that the cystocarps of some of the

Rhodophycez develop apogamously, basing his conclusions on

certain general peculiarities of the group and more particularly

on a study of Ptilota (Davis, '96). Three species of this genus

No. 464.] STUDIES ON PLANT CELL.— VII. 563

were investigated and no developments from the carpogonia

were found, but the cystocarp in all cases arose from a cell near

the base of the group of procarps. These conditions together

with the rarity of male plants on the American coasts (none

have ever been reported) give strong evidence for apogamy in

Ptilota. There are a number of genera of the Rhodophycez

where similar conditions seem to obtain and which lead one to

suspect that apogamy may not be very exceptional. However,

the subject has been very little studied.

As is well known, the Ascomycetes furnish numbers of illus-

trations where ascogonia have not been found or appear in what

seem to be reduced conditions and even when accompanied by

so called antheridial filaments these latter have not been estab-

lished as functional. De Bary recognized the possibility of

apogamy in the development of the ascocarps of these forms

and very little critical study has been given to them since his

time. The trend of. investigations in this group has been

towards the more interesting problems of the establishment of

sexuality in a few well known forms (e. g., Gymnoascus, Sphe-

rotheca, Pyronema, Monoascus, and among the lichens and

Laboulbeniacez.)

It is generally believed that no sexual organs are present in

the higher Basidiomycetes (Autobasidiomycetes). But the

recent studies of Blackman (:04a) in the Uredinales, taken in

relation to the well known nuclear fusions in the basidium, pre-

ceded by a mycelium containing paired (conjugate) nuclei, make

it seem very probable that former sexual processes in the Basi-

diomycetes have been replaced by a remarkable type of apog-

amous development of a sporophyte generation. Blackman has

traced the origin of the paired nuclei in the Uredinales (Phrag-

midium) to a structure preceding the ecidium, a structure which

seems to be the remains of a female sexual organ. We will

take up this investigation presently. There is then much

reason for believing that a sporophyte generation in the Basi-

diomycetes arises apogamously in the creation of the paired

- nuclei and terminates with their fusion within the teleutospore

or basidium.

The leptosporangiate ferns have furnished some of the best

564 THE AMERICAN NATURALIST. [Voı. XXXIX.

illustrations of apogamy. Since Farlow’s discovery in 1874 of

an asexual sporophytic growth from the prothallus of Pteris

cretica the list of apogamous pteridophytes has steadily increased

until now the phenomenon is known in perhaps 25 forms. Far-

low's investigation was followed by an extended study of De

Bary (78) on a large number of forms in the Polypodiaceze and

resulted in the establishment of similar sporophytic outgrowths

in Aspidium falcatum and Aspidium filix-mas cristatum. De

Bary proposed the term apogamy (78, p. 479) for the general

phenomenon and distinguished two forms, apandry the suppres-

sion of the male sexual organs which results in a parthenoge-

netic development of the egg, and apogyny for the suppression

of the female. Sadebeck in the following year reported apog-

amy in Todea one of the Osmundaceze (Schenk’s Handbuch der

Botanik, vol. 1, p. 231, 1879) thus extending the phenomenon

to another family. And later apogamy was found in 77icho-

manes alatum one of the Hymenophyllaceze (Bower, '88) and

in Selaginella rupestris (Lyon, :04, p. 287).

The most important recent contribution on apogamy in ferns

is by Lang ('98, abstract in Annals of Bot., vol. 12, p. 251).

This paper presents an able discussion of the phenomenon in

its relation to alternation of generations and adds the very

interesting discovery of sporangia borne directly on prothalli that

were grown from spores. These sporangia were found in clus-

ters on a thickened lobe or process from the prothalli of Sco/o-

pendrium vulgare ramulosissimum and Nephrodium dilatum

cristatum gracile. The sporangia were perfectly normal in

structure and they matured spores. It is probable that the.

process is itself sporophytic in character, z. ¢., made up of cells

with double the number of chromosomes of the true gametophy-

tic portion of the prothallus, but cytological details are not

known. Lang’s study of the apogamous development of sporo-

phytic buds on several forms of the Polypodiacez is the most

detailed work on apogamy in the pteridophytes yet published.

The apogamous growths appeared as the result of cultures which

were watered entirely from below and exposed to direct sun-

light, important departures from normal conditions surrounding

fern prothalli In all cases the prothalli developed normal

No. 464] STUDIES ON PLANT CELL.— VII. 565

embryos when the conditions permitted of fertilization. We

shall refer to some general considerations of Lang in our sum-

mary and conclusions on apogamy.

The spermatophytes present some exceedingly interesting

examples of apogamous developments of embryos from nuclei

within the embryo-sac other than the egg, as from antipodals

(Allium odorum, Tretjakow, '95 ; Hegelmaier, '97) or synergids

(Alchemilla sericata, Murbeck, : 02) or nuclei in the endosperm

(Belanophora, Treub, '98; Lotsy, '99) but in these cases the

sporophyte number of chromosomes is apparently present

through a suppression of the reduction phenomenon of sporo-

genesis in the development of the embryo-sac.

We will now consider two studies which describe nuclear

fusions preliminary to the appearance of apogamy (Blackman,

:04a ; Farmer, Moore, and Digby, :03).

Blackman's (: 04a) observations on Phragmidium have cleared

up to a great degree our understanding of the life history of the

Uredinales. The chains of zcidiospores have been found to

arise serially from “fertile cells” which form a group at the

spot where an zcidium is to be developed. Each fertile cell

has above it a sterile cell which, however, breaks down. The

sterile and the “fertile cell" together may represent a female

sexual organ, the sterile cell perhaps standing for the remains of

a receptive structure similar to a trichogyne. The spermogonium

consists of a large mass of antheridial filaments that abjoint

sperms which are no longer functional. It is of course uncer-

tain whether the * fertile cells” are morphologically the original

female gametes since they may readily be other cells drawn into

the process of apogamy. The “fertile cell" is stimulated to

activity by the entrance of a second nucleus either from an

adjacent hypha or from the cell below.. The second nucleus

does not fuse with the original nucleus in the “ fertile cell " but

the two come to lie close together as a paired or conjugate

The two nuclei of the pair divide simultaneously

nucleus. ")

ong series of nuclear divi-

(conjugate mitosis) throughout a |

. sions, beginning with the formation of zecidiospores and through

the vegetative history which follows up to the production of the

teleutospores where the members of the last pairs unite to form

566 - THE AMERICAN NATURALIST. (Nor: XXXIX.

the single fusion nuclei within these reproductive cells. There

is much evidence that the period in the life history characterized

by the presence of paired nuclei represents a sporophyte phase.

Blackman (:04a, p. 353) regards the process by which the

second nucleus enters the “fertile cell,” resulting in the conju-

gate nuclei, as a reduced form of ordinary fertilization. I have

already pointed out in Section IV, “ Asexual Cell Unions and

Nuclear Fusions,’’ what seem to me to be serious objections to

the use of the term fertilization when it is clear that the second

nucleus in the pair is morphologically not a gamete nucleus, and

the subject was also taken up in the account of fertilization in

the present section. Whatever may be the physiological inter-

pretation of this remarkable phenomenon it seems to me clearly

a substitute process for a former sexual condition and involves

other elements than the original gametes and as such, is a typi-

cal illustration of apogamy.

It seems probable that further studies in the Basidiomycetes

will determine a similar origin for the paired nuclei preceding

the basidium to that of Phragmidium but without any trace of

former sexual organs at least in the higher groups. And these

conditions must signify the complete disappearance of structures

representing sexual organs and the substitution of an apogamous

development of the sporophyte generation for the sexual act.

In this connection the interesting nuclear fusions in the ascus

are of great interest for they may hold relations to degenerate

sexual conditions in the Ascomycetes.

Farmer, Moore, and Digby (:03) have reported some remark-

able nuclear fusions preceding the apogamous development of

the sporophytes of Nephrodium, which have many points of

resemblance to the apogamous phenomena in the Uredinales

just described. These authors find that cells of the prothallus

from which the sporophytic outgrowths arise, become binucleate

through the migration of nuclei from neighboring cells. The

two nuclei may remain separate for some time or they may fuse

at once. They regard the whole process **as a kind 'of irregu-

lar fertilization" by which the outgrowth destined to form the

sporophyte becomes supplied with nuclei containing the double

number of chromosomes. It seems to me unfortunate to asso-

No. 464.) STUDIES ON PLANT CELL.— VII. 567

ciate the term fertilization with this phenomenon, whatever may

be the physiological significance of the nuclear fusions, because

we are not dealing with gametes and there cannot be involved

in the process anything of the long phylogenetic history of sex-

ual differentiation in the group. We considered these matters

in some detail in that portion of this section entitled * Fertiliza-

tion."

With respect to the factors which determine apogamy it must

be confessed that we are still in the dark. Lang’s ('98) studies

on fern prothalli, however, throw some light on the problem. In

some twenty forms of the Polypodiaceze apogamy resulted when

the prothalli were kept from direct contact with the water (7. e.,

were watered from below) and exposed to direct sunlight.

When watered from above these same forms developed normal

embryos from eggs. It is clear that the suppression of condi-

tions which make fertilization possible (7. e., water over the sur-

face of the prothallus), possibly aided by sunlight which may

cause irregularities of growth, induced the development of cylin-

drical processes from which the apogamous sporophytes arose

and which bore sporangia in two forms. It seems hard to draw

more precise conclusions from these experiments other than that

the normal life history is checked at a critical period (fertiliza-

tion) and the plant is forced into expressions of vegetative

activity. The conclusions of Farmer, Moore, and Digby (:03)

offer an explanation of how the developments may take on

sporophytic characters through the fusion of nuclei in the tis-

sues and the establishment of a sporophyte number of chromo-

somes.

Strasburger suggests that apogamy in Alchemilla may be the

result of a weakening of sexual power associated with excessive

mutative tendencies. This would seem to imply that excep-

tional vegetative activity, with the appearance of much variation

under favoring conditions, may be combined with apogamy. It

is of course a well known fact that a high degree of cultivation

tends to lessen the fertility of a form unless guarded by careful

selection. A weakened sexual fertility due to excessive vegeta-

tive activity is likely to be replaced by forms of vegetative

reproduction. When the process of sporogenesis becomes so

568 THE AMERICAN NATURALIST. | (Vot. XXXIX.

reduced or modified that the female gametophyte retains the

sporophyte number of chromosomes as in the embryo-sac of

Alchemilla and Thalictrum the apogamous development of em-

bryos is to be expected.

The discovery of apospory in such variable and perhaps

mutating genera as Alchemilla, Taraxacum, and Hieracium sug-

gests quite a new line of research with possibilities of a clearer

understanding of the origin of mutations. It is very interesting

that these widespread and successful genera should give evidence

of such strong apogamous habits for it seems to indicate an evo-

lutionary tendency in the higher plants of great significance.

These forms with Thalictrum are representatives of three large,

divergent and very successful orders (Ranales, Rosales, and

Compositales) and it suggests the probability that apogamy will

be found to be widespread in the spermatophytes. Its bearing

on the establishment of extreme variations and mutations may

be of the utmost significance for it is clear that the suppression

of sexuality would remove sports and mutants at once from the

swamping effects of cross-fertilization. The sudden appearance

of mutants in some groups and their ability to hold true may

indeed be found to rest on the establishment of apogamy in the

form. This is at least a possibility which must be considered in

cytological investigations on mutants and has not yet received

attention.

The subject of apogamy touches another topic of importance,

namely, the theory of homologous generations as contrasted with

antithetic generations in comparisons of sporophyte with gameto-

phyte. We shall not take up this discussion in detail here. It

must have been apparent to the reader that the present treat-

ment of the critical periods in the life history of plants is based

on the conviction of the correctness of the latter view which has

had the support of Celakovsky, Strasburger, Bower, Vaisey, and

Klebs. The theory of homologous generations as held by

Pringsheim and Scott is admirably discussed by Lang (798) in

connection with his studies on apogamy and also in a briefer

Sone. rum

lent support to the : ng on UE : peu

eory of homologous generations since the

No. 464.) STUDIES ON PLANT CELL.— VII. 569

prothallus can so readily take on sporophytic potentialities and

the sporophyte develop gametophytes vegetatively. But Lang

recognized that the importance of this evidence would be mini-

mized should it be found to depend on changes of nuclear struc-

ture. These nuclear changes have been established at least for

apogamy, either in the suppression of the reduction phenomena

of sporogenesis or by the substitution of asexual nuclear fusions

for the sexual act, and the argument for antithetic alternation

of generations seems to the writer stronger to-day than ever

before.

6. APOSPORY.

Apospory is the suppression of all processes of sporogenesis

and the development of a gametophyte generation directly from

the sporophyte. The term was first proposed by Vines (Jour.

of Bot., 1878, p. 355) in a discussion of the life history of Chara

and adopted by Bower ('86, '87) in a general treatment of the

subject based on Druery's (86a, ’86b) discoveries of prothalli

developed in place of sporangia directly upon the leaves of

Athyrium filix-femina and its variety clarissima. The phe-

nomenon of apospory is best known among the ferns where it

has been most extensively studied but so far no cytological inves-

tigations have been published. Since apospory results in the

development of a gametophyte generation (presumably with the

gametophyte number of chromosomes) without the preliminary

process of sporogenesis it becomes a very interesting problem to

know just how this reduction of the chromosomes is effected.

Apospory is probably not uncommon in the mosses and has

also been reported for the liverwort Anthoceros. The inde-

pendent studies of Pringsheim (76) and Stahl (76) established

the facts that pieces of the sporophyte stalk (seta) of Hypnum,

Amblystegium, Bryum, and Ceratodon when placed on damp

soil developed a protonema which in its turn produced leafy moss

Stahl also found in Ceratodon that protonemata

he capsule wall and Brizi ('92) discovered a

nt from the atrophied capsule of Funaria

’99a, p. 421) has confirmed the conclu-

gametophytes.

may arise from t

similar developme

hygrometrica. Correns (

570 THE AMERICAN NATURALIST. [Vor. XXXIX.

sions of Pringsheim and Stahl in species of Funaria, Hypnum,

and Amblystegium and obtained negative results in a number of

other forms, and presents an excellent review of the subject.

Lang (:o1) discovered that small pieces of the sporophyte of

Anthoceros levis when laid on damp sand produced green out-

growths which took on the structure of young gametophytes and

developed rhizoids. These aposporous gametophytes most com-

monly arose from subepidermal cells, but they may come from

any layer of the cortex down to the archesporial cylinder. It

seems probable that the mosses at least among the bryophytes

are able to reproduce themselves apogamously without difficulty,

when normal processes of sporogenesis are interfered with and

if the sporophytic tissue is in contact with moisture.

The leptosporangiate ferns, however, furnish the most con-

spicuous illustrations of apospory as they do of apogamy.

Indeed, the two phenomena are known to occur in the same

form in a number of instances (e. g., Athyrium filix-femina,

Nephrodium filix-mas, Scolopendrium vulgare, Trichomanes ala-

Zum, etc.). Beginning with the discovery by Druery (’86a,

'86b) of apospory in Athyrium filix-femina and its variety

clarissima the list has steadily grown until now apospory is

recorded for about ten forms. In Druery's forms the prothalli

developed from arrested sporangia and the spore alone is left out

of the life cycle. But Bower (86) very shortly brought forward

In Polystichum angulare pulcherrimum a form in which prothalli

are developed as simple vegetative outgrowths from the tips of

the leaves and the life history is thus shortened by the omission

of both spores and sporangia. This condition is exactly analo-

Sous to the development of protonemata from vegetative cells of

the sporophytes of mosses and Anthoceros. The following year

Bower (87) presented a very full account of the forms of Athy-

rium and Polystichum just described, and a general discussion of

the phenomenon of apospory. Bower ('88) then extended the

illustrations of apospory to two species of Trichomanes, of the

Hy menophyllacez ; Farlow (89) reported it for Preris aquilina,

and Druery (93) in Lastrea pseudo-mas cristata and (95) for

UN vulgare crispum. The exceptional amount of :

lation both in nature and under cultivation has not been

No. 464.] STUDIES ON PLANT CELL.— VH. 571

generally appreciated and the studies on apospory and apogamy

indicate that much of it is associated with these fundamental

modifications of the life history (Druery, : 01).

As to the cause of apospory we are as much in the dark as in

the case of apogamy. The phenomenon is clearly associated in

some forms with disturbances in the normal vegetative life of

the sporophytes. This is particularly true in the cases of mosses

and Anthoceros and has been suggested for the ferns. Thus

aposporous developments in Pteris aguilina are from leaves which

are generally smaller than the normal and whose margins are

curled so that the leaf often appears somewhat withered and is

easily recognized at a distance. Bower ('87, p. 322) is inclined

to regard the phenomenon in the ferns as a sport and does not

consider that it has deep morphological significance or that it

offers serious difficulty to the acceptance of the theory of an

antithetic alternation of generations.

As we have stated there have been no cytological studies upon

apospory but there seem to be two possible explanations. That

which is likely to suggest itself first calls for reduction phenom-

ena at the time of the aposporous development by which the nuclei

of the sporophytic tissues may come to contain the gametophyte

number of chromosomes and are therefore capable of developing

the sexual generation. But there is another possibility which

has not yet been considered. We know for several of the sper-

matophytes (Antennaria, Juel, :00; Thalictrum, Overton, :04;

Alchemilla, Strasburger, : 04c) that the processes of sporogenesis

may be suppressed and yet a structure be developed with the

morphology of the gametophyte generation. Thus the embryo-

sac will contain the usual number of nuclei grouped in the typ-

ical manner but these nuclei still have the sporophyte count of

It seems probable then that the development of

erference with the nor-

chromosomes.

a gametophyte may result through an int

mal life history and under conditions favorable to the game-

tophyte even though the nuclei retain the sporophyte number

of chromosomes. And it is possible that some of the aposporous

developments in bryophytes and pteridophytes may be of this

character. It is quite futile at present to carry this speculation

further. What is desired is some cytological facts.

572 THE AMERICAN- NATURALIST... (VoL; XXXIX,

B V

7. HYBRIDIZATION. ~

This is not to be a detailed discussion of the facts and theories

of hybridization, a subject far too extensive for the purposes òf

our treatment. We shall only consider some of the bearings of

the recent studies on fertilization and reduction phenomena upon

the problems of hybridization treating it as a critical phasg in

the life history of the organisms concerned. Until recently the

attempts to formulate definite laws for the formation of hybrids

and their progeny upon a physical basis have not been satisfac-

tory. But the work of a number of breeders all of whom ‘ewe

their results in large part to a quick appreciation of Mendel's

epoch-making contributions have brought much order out, of

what was a very confused subject. And accompanying" the

work of this group must be added the equally important con-

clusions of a number of cytologists whose investigations ori the

structure and behavior of nuclei in the critical periods of fertil-

ization and chromosome reduction have done much to place

Mendelian principles upon a cytological basis. We shall deal

with the work of the latter group, for their contributions cogcern

intimately the subject matter of these papers.

We shall not review the conclusions of Mendel except to point

out the relations of some of his principles to cytological phenom-

ena. The two papers of Mendel appeared in the proceedings of

a natural history society of Brünn, Austria, under the dates 1865

and 1869. They lay buried until 1900 when De Wes, Cogrens,

and Tschermak independently rediscovered themgand called the

attention of the scientific world to their worth, ®@ Soon after,

Bateson published a translation of the two papers (Mendel's

Principles of Heredity, Cambridge, 1902) with an introduction

and a defense against the criticisms of Professor Wheldon. There

have naturally been many reviews and short discussions of Men-

delian theories and among them that of Castle entitled “ Mendel’s

Laws of Heredity " (Science, vol. 18, p. 396, 1903) and Profes-

sor Bailey’s “Lecture IV" in Plant Breeding, 1904, will per-.

haps give the reader the clearest and most concise statements.

The most striking feature of Mendel’s investigations and those

No. 464] STUDIES ON PLANT CELL—VH. 573

of others, who have confirmed his conclusions, is the discovery

in a number of animals and plants that the germ cells of the

hybrid may be pure with respect to certain characters of the

parents which are crossed. This principle is not without excep-

tions where the conditions are apparently complicated by unusual

factors but the phenomenon when present is so striking as to

command immediate attention and call for an explanation on a

cytological basis. The purity of the germ cells of hybrids means

in the words of Castle that **the hybrid, whatever its own char-

acter, produces ripe germ cells which bear only the pure char-

acters of one parent or the other." Thus if two forms A and B

are crossed the hybrid will have embodied in itself the characters

AB, one of which however may lie latent, 7. ¢., may not be visi-

ble in the hybrid. Such a latent character when present is

termed recessive while the prominent character is termed domi-

nant. Ina simple case some of the offspring of the hybrid AB

will be found to have the character of A alone, some of them of

B alone, and some of them will again have the mixed characters

AB. If experiments are carried out on an extensive scale the

proportions of these offspring from the hybrid may exhibit the

remarkable fact that there are about twice as many forms of AB

as either A or B, z. e, the proportions of A's, AB's, and B's are

in the ratio of 1:2:1. Furthermore the offspring of A when

bred among themselves remain absolutely true producing a suc-

cession of pure forms all A's and the same results follow when

the offspring of B are closely bred. But when forms with the

mixed characters AB are bred with one another their offspring

break up as before into three types A, AB, and B in numerical

proportions expressed by the same ratio 1:2:1. The history

is simply told in the following diagram where the number of off-

spring is assumed to be 4.

Acei E IDAs. oss: 64 A

( 2A.....- BA. ae 32 A

Form A ( 4A: +... UM

Hybrid AB< 2AB« 4 AB4 SAB! ı6AB

4B... 16 B

roma p | 2B....-. l ERI VS 32 B

1B e 4B... 16 B. ose 64 B

574 THE AMERICAN NATURALIST. [Vor. XXXIX.

This remarkable proportion of forms derived from the hybrids

AB, i. e, A, AB, and B in the ratio 1:2: 1 can only be explained

on the assumption that the germ cells of the hybrid are pure

with respect to the characters of either one or the other of the

parents. The gametes from the hybrid, with the pure charac-

ters of either A or B and approximately equal in number, may

unite with one another in three possible combinations AA, AB,

or BB forming three types of offspring, one pure A, another

mixed AB, and the last pure B. By the law of chance the pro-

portions of these combinations (AA, AB, ànd BB) in a simple

case will be in the ratio 1:2:1. This assumption of the purity

of the germ cells of hybrids has been found to conform with the

facts ina number of simple experiments where two characters

such as A and B were sharply contrasted. When one of the

characters in the hybrid is dominant and the other recessive the

ratio can be expressed as D: DR: R as 1:2: 1 which is merely

a substitution of D and R for the characters A and B.

There are of course many factors which tend to modify the

ratios as stated above and complicate the results. Thus the

normal number of gametes may be of varying vigor and mortal-

ity so that there will be proportionately more or less of one type

of fusion than is called for by the law of chance. Sometimes

the characters of the parents remain evenly balanced in the

hybrid and refuse to split up in the succeeding generations,

remaining in a stable union in the germ cells produced by the

hybrid. Such conditions prove exceptions both to the law of

dominance and to that of purity of the germ cells. From these

exceptions and particularly the last it is difficult to believe that

any large proportion of the germ cells is absolutely pure, i. e.,

bearing only the pure characters of one parent or the other.

However, there is much evidence from our knowledge of the

distribution of the chromosomes from one generation to the next,

that certain relations are possible in the separation of germ plasm

which approximate the ratios of Mendel's law and while rarely

giving absolutely pure germ cells nevertheless do make possible

a large proportion of re/atively pure cells.

Let us examine now the chromosome history as a possible

physical basis for the Mendelian principles. Such considerations

No. 464.] STUDIES ON PLANT CELL.— VII. 575

must rest ón the assumption of what is termed the individuality

of the chromosome. This means that the chromosome is

believed to be a permanent organ of the cell which never loses

its organic entity although the form may be frequently obscured,

as in the resting nucleus, and which reproduces by fission during

mitosis. We have given in other connections the evidence upon

which the above view rests, evidence accumulated from the

studies of the critical periods of gametogenesis, fertilization, and

sporogenesis (with its reduction phenomena) in plants and of

gametogenesis and fertilization in animals. All investigations

indicate that paternal and maternal chromosomes maintain com-

plete independence in the sexually formed cell or fertilized egg

and in the mitoses of cleavage so far as these have been fol.

lowed. Also, descendants of the chromosomes which became

associated with fertilization have been recognized by their form

at the end of the life history during the reduction phenomena of

gametogenesis in certain animals (Sutton, :02, :03; Montgom-

ery, : 04) and of sporogenesis in the hybrids of Drosera (Rosen-

berg, :04a, :04b). Furthermore, the entire history of chromo-

some reduction in both animals and plants finds a satisfactory

explanation only in the belief that descendants of maternal and

paternal chromosomes are distributed as organic entities by the

peculiar mitoses of this period.

There is a general agreement that the somatic chromosomes

of animals and the sporophytic of plants become grouped in

pairs to form bivalent structures before the heterotypic mitosis

of the reduction division whether this be present in the primary

gametocyte (animals) or the spore mother-cell (plants). The

bivalent chromosomes (pairs of chromosomes, dyads) may be-

come transformed into tetrads before the heterotypic mitosis by

a division of each chromosome in the pair, as is:characteristic of

animals, or this division may be delayed until a somewhat later

period during the heterotypic mitosis, as in plants. We are not

concerned now with the dispute as to how the pairs of chromo-

somes come to lie side by side to-form the bivalent structure or

how tetrads are developed, activities which may indeed be vari-

ous in different types and which will only be ‘understood by a

greater body of observations than we have at present (see dis-

576 THE AMERICAN NATURALIST. (VoL. XXXIX.

cussion of “ Reduction of Chromosomes ”). The’ important

point for us is the belief that the appearance of the bivalent

chromosomes during reduction is due to the temporary union of

somatic or sporophytic chromosomes in pairs and further that

the reduciag divisions distribute the members of the pair, which

are believed to be descendants of the maternal and paternal

chromosomes of the previous generation, as organic entities to

the generation which is to follow.

It is difficult to overestimate the importance of this general-

ization. If the program prove to be correct as stated above and

if the chromosome is established beyond doubt as a self-perpet-

uating organ of the cell and a bearer of hereditary characters

we have then the possibility of studying the actual manner in

which these structures are passed on from one generation to the

next and perhaps determine the ratios or combinations through

which the distribution is effected. The difficulty of making an

exact determination of ratios in any form so far studied lies in

our inability to distinguish the chromosomes of maternal and

paternal origin. There is much evidence that the pairs of

somatic and sporophytic elements, which form the bivalent

chromosomes of the reduction mitoses of animals and plants

respectively, are of different parentage but we do not know

whether or not there is any rule in the arrangement of the pairs

on the spindles of these mitoses although this is hardly to be

expected. Cannon (:02, :03a) and others have held that the

mitoses of reduction brought about the complete separation of

the maternal and paternal chromosomes so that two of the

resultant four nuclei contain chromosomes from one parent and

two from the other, and the germ cells are in consequence abso-

/utely pure in character. But this view was soon shown by Sut-

ton (:03, p. 233; accepted by Cannon, :03b) to be at variance

with the facts of breeding for if germ cells of hybrids are a£so-

/utely pure there could be no further change by cross-breeding

and the first cross would be repeated over and over again with-

out any divergence from the type, which is contrary to experi-

ence and fact. The pairs of chromosomes are probably arranged

in every possible order and the maternal and paternal elements

are distributed in every possible combination by the reducing

No. 464.] STUDIES ON PLANT CELL— VN: 577

divisions. If this is true then by the law of chance the propor-

tions of germ cells of the hybrid which are adsolutely pure (con-

taining chromosomes entirely from one parent) would be small.

Likewise there would be a small proportion of germ cells in

which the paternal and maternal chromosomes are equally dis-

tributed. And in contrast to these two groups the great major-

ity of germ cells would have a marked preponderance of chromo-

somes derived from one parent or the other and this condition

may be termed one of relative purity.

We shall now summarize the cytological evidence for the con-

clusions of the paragraph above, first with respect to the actual

distribution of the somatic and sporophytic chromosomes as

entities during the mitoses of reduction, and second as to the

probability of the bivalent chromosomes consisting of a pair of

maternal and paternal elements. The evidence on the first

point has been treated as regards plants in our own account of

* Reduction of the Chromosomes ” and need not be repeated.

With respect to the possibilities of distinguishing maternal and

paternal chromosomes throughout a life history and especially

at the period of chromosome reduction we must consider briefly

the remarkably favorable studies of Sutton, Montgomery, Moenk-

haus, Baumgartner, and Rosenberg.

Sutton (:02, :03) discovered in the “ lubber grasshopper ”

(Brachystola magna) a form in which the somatic chromosomes,

23 in number, are markedly different in size, presenting a graded

series with respect to pairs in which the two elements are ap-

proximately equal. There are then 11 types of chromosomes in

two groups, a pair of each type, and in addition an accessory

chromosome which remains apart from the rest in a special

vesicle of its own. These two sets of 11 chromosomes appear

with regularity throughout the mitoses leading up to the reduc-

tion divisions of spermatogenesis. Previous to the reducing

divisions the chromosomes of each pair become closely asso-

ciated end to end so that 11 threads appear which form 11 biva-

lent chromosomes (dyads) that later become tetrads through the

division of each chromosome in the pair. Sutton concludes that

the somatic chromosomes which make up each bivalent structure

conjugate during synapsis and that the transverse fission which

578 THE AMERICAN NATURALIST. (VoL. XXXIX.

appears during the formation of the tetrad simply separates the

two somatic chromosomes of the pair, while the longitudinal

fission is the usual division of chromosomes, appearing prema-

turely at this time. The conclusion is natural that the two

series of the r1 pairs consist of maternal and paternal chromo- |

somes which are distributed as organic entities by the reducing

divisions. But there are no reasons for supposing that all of

the paternal chromosomes will pass into one set of germ cells

and all of the maternal into another but rather that the ratios

of distribution will be by the law of chance according to which

the great majority of germ cells will have a marked preponder-

ance of chromosomes from one parent or the other, and will

therefore be re/atively pure. An exceedingly small proportion

of germ cells may, by the law of chance, contain chromosomes

entirely of maternal or paternal extraction, and an equally small

proportion may contain 6 chromosomes of one parent and 5 of

the other. The accessory chromosome divides but once during

the mitoses of spermatogenesis so that two of the spermatozoids

have 11 chromosomes and two 12. No accessory chromosome

appears in the mitoses of oógenesis indicating that the female

insect lacks this structure which confirms the belief of McClung

(: 02) and others that the accessory chromosome is a determin-

ant of the male sex.

Montgomery in a series of studies upon insects and Amphi-

bians, which are summarized in a recent paper (:04), reached

conclusions in striking support of the theories of the individu-

ality of the chromosomes, the association of pairs of chromo-

somes during synapsis to form bivalent structures and the prob-

ability of the elements of each pair (bivalent chromosomes) being

of maternal and paternal origin respectively. His results on the

last point are of especial interest in relation to hybridization.

In a large number of insects, chiefly Hemiptera, Montgomery

has found pairs of chromosomes, which he terms heterochromo-

somes, much smaller or much larger than the others and these

may be followed through mitosis from one nucleus to another.

The heterochromosomes of each pair are known to unite with

one another during synapsis to form the bivalent chromosomes

of the reduction mitoses and they then become separated, each

No. 46041] -| STUDIES ON PLANT CELL— VII. 579

dividing once, so that every germ cell receives a single hetero-

chromosome of whatever sort. Fertilization then brings the

heterochromosomes together again in pairs until the next period

of chromosome reduction. This history is then parallel to

Sutton's account of the lubber grasshopper (Brachystola), the

difference being that the latter form presents a remarkably

graded set of paired chromosomes. Montgomery regards the

small chromosomes and the accessory chromosome as structures

tending to disappear in a process of evolution from a higher

chromosomal number to a lower.

Moenkhaus (:04) crossed reciprocally two species of fishes

(Fundulus heteroclitus and Menidia notata) and obtained hybrid

embryos which reached an advanced stage of development.

The chromosomes of the parents are readily distinguished by

size and form. These chromosomes were followed throughout

` the development of the hybrid embryo and were found to retain

their peculiarities so that the two sets may be easily separated

in favorable tissues. This investigation furnishes some of the

strongest evidence of the individuality of the chromosome and

the complete independence throughout the life history of the

two sets derived from each parent. Could these hybrid embryos

be raised to maturity we should expect to find during spermato-

genesis and oógenesis an association of the chromosomes in

pairs, those of paternal extraction with those of maternal to

form the bivalent chromosomes preliminary to the reducing divi-

sions, and a distribution to the sexual cells in varying propor-

tions which would, however, give a very large ratio of relatively

pure germ cells. ne

Baumgartner (:04) in studies upon spermatogenesis in the

cricket (Gryllus) was able to distinguish the chromosomes. by

their form, following them through the mitoses of reduction.

Most of the chromosomes have the form of straight or bent rods

but there are apparently two rings in each set in G. domesticus.

The variation in the form of chromosomes in the nucleus is well

known but it has not been supposed that a definite form might

be characteristic of an element and be maintained throughout

the successive mitoses of a life history as seems probable from

Baumgartner's results.

5 8o THE AMERICAN NATURALIST. (VoL. XXXIX.

Rosenberg's (:04a, : 04b) studies on hybrids of Drosera rotun-

difolia (with ten chromosomes in the gametophyte) and D. longi-

folia (with twenty chromosomes) offer clear evidence that the

chromosomes which unite in pairs to form bivalent structures

preliminary to the reduction phenomena of sporogenesis are of

different parentage. The sporophyte number of chromosomes

in the hybrid is thirty, as would be expected. The reduced

number appearing at the first mitosis of sporogenesis is, however,

not fifteen but twenty chromosomes, ten of which are plainly

double the size of the other ten. The explanation of this inter-

esting condition is that the ten chromosomes of 2. rotundifolia

unite with one half of the twenty chromosomes of D, longifolia

giving ten large bivalent structures accompanied by the ten

chromosomes of D. longifolia which are without mates. This

explanation finds clear support in the facts that the chromo-

somes of D. rotundifolia are larger than those of D. longifolia |

and that the bivalent structure consists of a larger and a smaller

element thus giving clear evidence that the pairs of chromosomes

Which unite in Drosera are of different parentage. The single

chromosomes which are without mates may pass to one or the

other of the poles of the spindle or may be left behind when the

daughter nuclei are formed.

This group of investigations illustrates very clearly the charac-

ter of the evidence that is leading many biologists to assign to

the chromosomes the functions of bearing and distributing hered-

itary characters. The question at once comes up as to whether

or not the chromosomes may differ among themselves to a

greater or less extent even in the same species or individual.

Montgomery, Sutton, with others, have established a difference

in the szze of chromosomes. Baumgartner distinguishes differ-

ences in form in the same species and the studies of Moenkhaus

and Rosenberg have shown that the chromosomes of different

parents may retain their peculiarities of form in hybrids and be

really separated. To these investigations should be added the

recent conclusions of Boveri (102, :04), that chromosomes actu-

ally differ in function. Boveri found that the chromosomes of

eggs of echinoderms that were fertilized by two or more sperms

are distributed by multipolar spindles to a varying number of

No. 464.] STUDIES ON PLANT CELL.— VII. 581

blastomeres which in consequence received a varying number

and assortment of chromosomes. Boveri then separated these

blastomeres and followed their independent development into

larval stages which exhibited marked differences in form that

could be correlated with the irregularities in the number of

chromosomes contained in each, thus suggesting that specific

chromosomes have specific functions. With this sort of evi-

dence accumulating from both the morphological and physio-

logical side it is not surprising that many biologists believe

that specific characters are actually held or are controlled by

chromosomes or groups of chromosomes.

Such views of course presuppose that the chromosomes retain

a high degree of independence of one another and that variation

is expressed chiefly through different combinations of chromo-

somes and not by modifications of the chromosomes themselves.

Yet there is strong evidence of an actual mixing or interchange

of the idioplasm among the chromosomes. This possibility

"which is of course contradictory to the view of the complete

independence of the chromosomes finds its chief support in the

close association of the pairs of chromosomes with the organiza-

tion of the reduced number of bivalent structures during synap-

sis. These pairs have been reported so intimately united as to

be actually fused. Allen (:05) has described for Lilium the

union of two sets of chromomeres, one believed to be derived

from a paternal spirem and the other from a maternal, which

come to lie side by side during synapsis and unite to form a

spirem with a single series of fusion chromomeres. This single

(fusion) spirem later splits longitudinally and the two halves are

regarded as again representing maternal and paternal spirems

but there are evidently opportunities during the period of fusion

for significant reciprocal interaction between the two idioplasms.

This conception of the fusion of idioplasm from the two, parents

is an old view which has been held by such well known biologists

as Hertwig and Strasburger. ey

De Vries (: 03) has recently discussed the significance of the

pairing of chromosomes before the heterotypic mitosis in relation

to the theory of pangenesis. He conceives the paternal and

maternal chromosomes as coming together during synapsis in

582 THE AMERICAN NATURALIST. | (Vor. XXXIX.

homologous pairs so that corresponding pangenes or groups of

pangenes are brought together and that there may be a mutual

interchange or transfer of idioplasm with the result that the

chromosomes after separating may contain a mixed set of pan-

genes although each is supposed to have a complete assortment.

The interchange makes possible all forms of combinations of the

pangenes in the two sets, according to the laws of chance,

which might be expressed in proportions that would approximate

in some cases the ratios of Mendel. If the parents are widely

different from one another their idioplasm may not correspond

' sufficiently to make possible this union and interchange of

pangenes so that the process is suppressed and the hybrid is

sterile.

Allen (:05, p. 247) points out that the union of two spirems

during synapsis with the fusion of two sets of chromomeres,

according to his account of the lily, offers a number of possibil-

ities with respect to the constitution of idioplasm following the

reduction mitosis. (1) There may be such a fusion of elemen-

tary units that a single idioplasm is formed different from either

parent which would of course be distributed equally to the

reproductive cells by the subsequent double longitudinal fission

of the single (fusion) spirem. This would be expected to give

hybrids of much the same form in every instance and these

would remain stable (constant). (2) There may be a greater or

less mixing or modification: of units but without the actual union

and formation of a new idioplasm in the hybrid. Then by the

splitting of the single (fusion) spirem there might result a dis-

tribution of the mixed idioplasm following ratios or proportions

approximating Mendel's law. (3) There may be in part a fusion

and in part a mixing of idioplasm which would be expected to

result in a varied combination of parental characters in the off-

"pp (4) While the chromosomes may be distributed accord-

TEN ratios similar to Mendel's principles their respective

characters may be greatly modified by their temporary union

during sy napsis. (5) Portions of the idioplasm may interact

upon one another so that when they are separated by the reduc-

tion mitoses their character has become variously modified. (6)

Finally, Allen, of course, recognizes the possibility that parental

No. 464] STUDIES ON PLANT CELL.— VII. 583

idioplasm may be separated so purely by the longitudinal split-

ting of the single (fusion) spirem or through the distribution of

unmodified sporophytic or somatic chromosomes as to give abso-

lutely and relatively pure germ cells through Mendelian laws.

Allen's discussion, very briefly summarized above, is impor-

tant for the emphasis which is laid upon the significance of a

possible mixing of the parental idioplasms in the more or less

complete union of chromatic material, which is generally recog-

nized as characteristic of synapsis. There is a general tendency

to rest content when the chromosomes are accounted for as

units while they are merely the grosser form of expression of

the idioplasm whose final architecture is intricate far beyond our

present powers of analysis. Allen's own studies upon the events

of synapsis in the lily with the regular fusion in pairs of chromo-

meres of different parentage may well cause one to hesitate in a

full acceptance of the chromosome as fixed and unchanged in its

organic constitution throughout the life history. The phenome-

non of hybridization is far too complex to be explained in terms

of simple ratios and while some characters may be paired or

correlated in proportions that can be expressed by mathematical

formulz there is little probability that the assemblage of charac-

ters which make the species can be so definitely grouped as the

strongest disciples of Mendel may hope. However, a great

forward step has been taken and we may expect important

results from the empirical methods so clearly defined by Mendel

and by the close investigation that cytologists are making

of the history of idioplasmic structures (chromosomes) during

ontogeny.

8. XENIA.

Xenia is the “immediate or direct effect of pollen on the

character of seeds and fruits." The term was first proposed by

Focke, in 1881, and is now well established. Xenia has long

been known to the plant breeder as one of the most interesting

and puzzling problems of hybridization. The botanist has nat-

urally looked for the results of hybridization in the development

of the embryo from the seed since: this structure has received

584 THE AMERICAN NATURALIST. [Voı. XXXIX.

the substance of the sperm nucleus of the male parent. But

facts have clearly shown that the pollen may also affect the

structure of the endosperm in the seed as well as cause the

development of the embryo. Since the endosperm holds no

genetic relation to the embryo it has seemed very remarkable

that it should take on hybrid qualities. It has also been claimed

that other regions of the seed or fruit, such as portions of the

pericarp were also affected, but it is doubtful whether this is

really so or at least whether such changes are truly a feature of

the protoplasmic structure and thus deeply seated in the organ-

ism as a feature of hybridization.

It is only within recent years that a satisfactory theory has

been suggested for the influence of pollen outside of the embryo.

And this explanation rests on the discovery of the activities of

the second sperm nucleus which enters the embryo-sac and which

is known in some cases to unite with the polar nuclei constitut-

ing a triple nuclear fusion within the sac that is generally known

as “double fertilization." We have briefly referred to the phe-

nomenon in the latter part of the account of * Asexual Cell

Unions and Nuclear Fusions” in Section IV and shall take it

up now in greater detail. The best account of xenia is a very

clear treatment by Webber, in 1900.

The explanation of xenia upon the facts of «double fertiliza-

tion" was proposed almost simultaneously by De Vries (799,

: 00), Correns ('99b), and Webber (:00). Double fertilization

was first observed by Nawaschin ('98) in Lilium and Fritillaria

and shortly after was described in greater detail by Guignard

_(99b) in other species of the same genera and in Endymion.

Since these discoveries the phenomenon has been reported by a

number of investigators in many other forms representing widely

divergent groups in the Monocotyledonz and Dicotyledonz and

there is every reason to believe that it is widespread in the angio-

sperms. A review of the recent literature is given by Coulter

and Chamberlain (Morphology of the Angiosperms, 1903, P- 156).

There is no fixed order in the events of the triple nuclear fusion

of “ double fertilization." The polar nuclei may have united at

the time when the pollen tube enters the embryo-sac, in which

case the second sperm nucleus coalesces with an organized fusion

No. 464] STUDIES ON PLANT CELL.— VII. 585

endosperm nucleus. Or, the two polar nuclei and the sperm

nucleus may all three fuse together practically simultaneously.

And again the sperm nucleus may unite first with one of the

polar nuclei and the second be drawn later into the triple fusion.

But no cases seem to have been reported in which but one polar

nucleus unites with the sperm leaving the other free although

such a combination may be expected. Also, no one has ob-

served an independent division of the sperm nucleus within the

endosperm, although as we shall see, there are reasons for believ-

ing that such a development may sometimes take place.

We have already given in Section IV the reason why these

triple nuclear fusions may be kept apart from sexual phenomena

since we have no knowledge of the phylogenetic history of the

processes involved. It seems best at least for the present to

regard the phenomenon as a special development associated with

the peculiar and highly specialized conditions within the embryo-

sac. This detailed and highly difficult problem of phylogeny has

no especial bearing on the physiological features of xenia with

which we are at present concerned.

The best understood examples of xenia are found in the

hybrids of maize and are clearly described in the very interest-

ing paper of Webber (:00). As is well known, some of the

varieties of corn are distinguished among other characters by

the color of the kernels, which are blue, red, yellow, and white,

and also by the surface, which is smooth in the starchy corns

(flint or dent) and wrinkled in the sugary sweet corns. When

well marked pure races are grown out of reach of chance cross-

pollination, the offspring remain true to their seed characters

but it has long been known that the varieties of corn hybridize

very readily so that when grown close together the ears will very

frequently present seeds mixed as to color and texture. Thus

when exposed to cross-pollination a corn which is characteris-

tically yellow or white may bear blue or red kernels or a form

with wrinkled and starchy kernels may develop smooth starchy

corn if varieties with these characters are in the vicinity. The

color character is known to lie in these examples in the outer

` layer of the endosperm (aleurone layer) and of course the food

material whether prevailingly starch or sugar, which gives the

586 THE AMERICAN NATURALIST. [VoL. XXXIX.

surface a texture smooth or wrinkled, is stored within the endo-

sperm. ;

The clearness of xenia in the maize has led to a number of

careful studies on cross-pollination beginning with the work of

Vilmorin (1866), Hildebrand (1867), and Friedrich Körnicke

(1872). The possible explanation of xenia in maize through

“double fertilization " which introduces qualities of the male

parent from the pollen into the endosperm was suggested by

experiments of De Vries on hybridizing maize in the summers

of 1898-99 and Correns and Webber in 1899. De Vries ('99,

: 00) pollinated a wrinkled-seeded sugar corn from a variety of

smooth starchy corn and obtained smooth starchy kernels which

when cultivated in the succeeding summer were found to be true

hybrids. He concluded that this furnished experimental proof

that the endosperm of the sugar corn was affected by the

entrance of a sperm nucleus from the starchy variety according

to the theory of “double fertilization " proposed by Nawaschin

(98)

Correns ('99b) in the same year expressed similar conclusions

in a clear statement of the theoretical aspects of the problem of

venia as found in Zea mays. Correns advanced a number of

propositions some of which should be noted for their speculative

interest. Thus he states (proposition 7) that the influence of

the new pollen (Z. e., from the male parent of the hybrid) is

expressed as xenia only in the endosperm and (proposition 8)

only in the pigment present or the chemical nature of the reserve

material whether starchy or sugary. If the two races differ

only in the presence of one character, as in the color of the

aleurone layer, that character is only found in xenia when

brought by the pollen (proposition 10). Xenia is then only

expressed in a hybrid (proposition 14) by the formation of a pig-

ment which the race of the female parent does not possess or of

a more complicated chemical compound (such as starch) in place

of a simpler (as dextrin). Correns (: O1) later presented in a

lengthy paper, beautifully illustrated, the full results of his

studies on xenia in maize with a discussion of the hybrids.

Webber (: 00) also simultaneously with De Vries and Correns

Conducted extensive experiments in hybridizing a number of

No. 464.] STUDIES ON PLANT CELL.— VI. 597

varieties of corn distinguished by the color of the kernels, which

were white, yellow, red, or blue and by the texture whether

smooth, hard, and starchy (dent or flint corn) or wrinkled and

sugary (sweet corn). The results of his investigation are admir-

ably presented with excellent illustrations. He found that the

smooth kernel and starchy endosperm of the dent and flint corn

were transmitted very conspicuously as xenia when these forms

were employed as the male in crossing with the sweet corns

whose kernels are wrinkled and sugary. The characters of the

sweet corns do not seem to be expressed as xenia when smooth,

starchy, dent corn is used as the female member of the hybrid.

This experiment would seem to support Correns’ proposition

number 14 that a more complicated compound is always formed

in xenia in place of a less complex. But Webber found that

flint corn, which is smooth and starchy, when pollinated with

a form of sweet corn developed the wrinkled kernel and sugary

type of endosperm of the male member indicating that this rule

of Correns is not universal. And McClure ('92) obtained simi-

lar results in crossing a white dent race with pollen of Black

Mexican which is a sugar corn with black kernels. The product

in this case showed xenia clearly in having the wrinkled blue-

black kernels of the male sugar corn.

Some of Webber's most striking results were obtained in pol-

linating yellow and white corns with blue-black and red races.

The color was transmitted as xenia in a most striking manner.

Webber agrees with other authors that the color is only present

in the endosperm of the kernels. Thus the red of certain dent

corn, which lies in the pericarp, is not passed on as xenia and

McClure observed the same facts in experiments with cranberry

corn whose color lies in the seed coat and is not transmitted

when employed as the male member in crossing with white

corns. Webber's experiments show, as do those of other inves-

tigators, that the absence of color in the kernels of the male

parent does not seem to affect the tint of the kernels when the

female is markedly colored, in agreement with Correns' proposi-

tion number ro. But Webber is not convinced that some

influence might not be exerted on colored corn when pollinated

from races with colorless endosperm, because of certain experi-

ments on variegated xenia which will be described presently.

588 THE AMERICAN NATURALIST. (VoL. XXXIX.

These experiments of De Vries, Correns, Webber, and others

have established experimentally the facts of xenia and Nawas-

chin’s theory of double fertilization seems to offer the. only

explanation of the phenomenon. But it was left to Guignard

(: 01) to make the concluding observation that a second sperm

nucleus does actually enter into the composition of the endo-

sperm of maize, and this fact clinched the argument which up

to this time had been a speculation.

Webber has made a very important addition to the theory of

“double fertilization " as an explanation of xenia in some obser-

vations and speculations on a mottled condition which is some-

times present when white corns are pollinated by colored. He

found that the color was sometimes only transmitted in spots as

when Hickory King was pollinated by Cuzco, or perhaps only

half a kernel may be colored. Webber offers the hypothesis

that the second sperm nucleus may enter the embryo-sac but

instead of uniting with the two polar nuclei to form a triple

fusion may itself divide separately and thus gives rise to a

progeny very different from the other endosperm nuclei.

There might then be two sets of nuclei in the endosperm one of

which is composed of nuclei which would come directly from

the male parent. These latter then might become distributed

throughout the embryo-sac but would tend to remain in groups

as multiplication progressed and would certainly be expected to

influence the character of the tissue which is formed later when

the walls are developed around the free nuclei. As Webber

expresses it, there might be formed islands of tissue in the

endosperm whose cells contain nuclei derived directly from the

second sperm and such tissue would be expected to show char-

acters of the male parent in spots as xenia. Again, if the sperm

nucleus should unite with only one of the polar nuclei and the

other should give rise to an independent progeny we should

expect similar mixed conditions in the endosperm, with xenia

only expressed in the areas dominated by nuclei containing

material derived from the sperm.

: There have been reported illustrations of xenia in tissues out-

side of the endosperm but we are fully justified in awaiting

their confirmation before accepting them, especially since some

No. 464.) STUDIES OF (PLANT CELL — Vii, 589

have failed to stand the test of critical investigation, in the

light of the present theory. Thus certain investigators have

reported xenia in the color of the seed coats of certain peas.

But Giltay ('93) in a series of experiments found no instance

where color was transmitted to these tissues. The pigments in

these plants lie in the cotyledons of the embryo which of course

are readily visible through the thin coats of the seed. While

the present theory of xenia is very recent and has been critic-

ally applied in few forms, it seems thoroughly satisfactory in

every particular with no clearly established evidence against it.

LITERATURE CITED IN SECTION V,“THE PLANT

CELL.”

ALLEN.

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p. 464.

ALLEN.

:05. Nuclear Division in the Pollen Mother-Cells of Zilium canadense.

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ATKINSON.

'99. Studies on Reduction in Plants. Bot. Gaz., vol. 29, p. t.

BAUMGARTNER.

:04. Some New Evidence for the Individuality of the Chromosomes.

Biol. Bull., vol. 8, p. 1.

BELAJEFF.

; Ueber die Reductionstheilung des Pflanzenkernes. Ber. d. deut.

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BEARD. ;

’95. On the Phenomena of Reproduction in Animals and Plants. Anti-

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BERGHS.

:04a. Depuis le spirem jusqu'aux chromosomes mürs dans la micro-

sporogénése d 'AZ/zum fistulosum et de Lilium lancifolium (spect-

osum). La Cellule, vol. 21, p. 173-

BERGHS. "m

:04b. Depuis la sporogonie jusqu'au spireme définitif dans la micro-

sporogénése de VAllium fistulosum. La Cellule, vol. 21, p. 383.

590 | THE AMERICAN NATURALIST. | [Vor. XXXIX.

BERGHs.

:05. La microsporogéaése de Convallaria maialis. La Cellule, vol.

22, p. 43

BITTER.

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BLACKMAN.

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BLACKMAN.

` 104b. On the P eeo of Fertilization to “ ai coat ” and “ Parthian:

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BOVERI.

:02. Ueber mehrpolige Mitosen als Mittel zur Analyse des Zellkerns.

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BOVERI.

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360.

BowER.

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Bower.

':88. On some Normal and Abnormal Developments of the Oöphyte in.

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ane ,

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CALKINS.

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CHAMBERLAIN.

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CANNON.

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CANNON.

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No. 464.] STUDIES ON PLANT CELL.— VIT. 59I

CANNON.

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CORRENS.

'99a. Untersuchungen über die Vermehrung der Laubmoose durch

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CORRENS.

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CORRENS.

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COULTER AND CHAMBERLA

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DRUERY.

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FARMER.

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'99. Les cinéses polliniques chez les Liliacées. Za Cellule, vol. 16,

P- 235-

GRÉGOIRE.

La reduction numérique des chromosomes et les cinèses de matu-

ration. La Cellule, vol. 21, p. 297.

GREGORY.

:04. ‘Spore Formation in Leptosporangiate Ferns. Annals of Bot.,

vol. 18, p. 445.

GUIGNARD

'84 Rechätches sur la structure et la division du noyau cellulaire.

Ann. d. Sci. Nat., Bot., ser. 6, vol. 17, p. 5-

GUIGNARD.

'85. Nouvelles recherches sur le noyau cellulaire, etc. Ann. d. Sci.

Nat., Bot., ser. 6, vol. 20, p. 310.

GUIGNARD.

Buil.

'89. Etude sur les phenoménes morphologique de la fécondation.

Soc. Bot. d. France, vol. 36, p. 106.

GUIGNARD.

'91. Nouvelles études sur la fécondation.

7, vol. 14, p. 163.

Ann. d. Sci. Nat., Bot., ser.

594 THE AMERICAN NATURALIST: [Vor. XXXIX.

GUIGNARD.

'99a. Le développement du pollen et la reduction chromatique dans le

Naias major. Arch. d' Anat. Mic., vol. 2, p. 455.

GUIGNARD.

'99b. Sur les anthérozoides et la double copulation sexuelle chez les

végétaux angiospermes. Compt. Rend., vol. 128, p.

GUIGNARD.

:01. La double fécondation dans le mais. Jour. Bot., vol. 15, p. 37.

HAECKER.

'98. Ueber vorbreitende Theilungsvorgänge bei Thieren und Pflanzen.

Verh. d. deut. zool. Gesellsch., vol. 8, p. 94.

TERE EMER.

Zur Kenntniss der Polyembryonie von Allium odorum, L. Bot.

Leil, Vol. 55, p. 133.

ISHIKAWA.

'97. Die Entwickelung der Pollenkórner von A//ium fistulosum, L., ein

Beitrag zur Chromosomenreduktion im Pflanzenreiche. /our. Coll.

Sct. Imp. Univ. Tokyo, vol. 10, p. 193.

JUEL

98. Parthenogenesis bei Antennaria alpina (L.) R. Br. Bot. Centralb.,

vol. 74, p. 369.

JUEL.

:00. Vergleichende Untersuchungen über typische und parthenogenet-

ische Fortpflanzung bei der Gattung Antennaria. Handl. Sven

Vetensk. Akad., vol. 33.

JUEL.

:04. Die Tetradentheilung in der Samenanlage von Taraxacum. Ark.

J. Bot. K. Svenska Vetens. Akad., vol. 2, no. 4.

KOENICKE.

:04. Die neueren Arbeiten über die Chromosomenreduction im Pflanzen-

reich und daran anschliessende karyokinetische Probleme. Bot.

Zeit., vol. 62, p. 305.

LANG.

'98. On Apogamy and the Development of Sporangia upon Fern Pro-

5 thalli. Phil. Trans. Roy. Soc. London, ser. B, vol. 190, p. 187.

ANG.

:01. On Apospory in Anthoceros levis. Annals of Bof. vol. 15, p.

LLovp.

:02. The Comparative €— of the Rubiacex. Mem. Torrey

Bot. Club, vol. 8, p.

Lorsv

'99. Belanofhora globosa Jungh. Eine wenigsten órtlich-verwittwete

anze. Ann. Jar. Bot. Buiten., ser. 2, vol. 1, p. 174-

No. 464.] STUDIES ON PLANT CELL.— VII. 595

Lorsv.

:03. Parthenogenesis bei Gze£u»zt ula Brogn. Flora, vol. 92, p. 307.

Lorsv

:04. Die Wendung der Dyaden beim Reifung der Tiereier als Stütze

für die Bivalenz der Chromosomen nach der numerischen Reduk-

tion. lora, vol. 93, p. 65.

:05. Die x-Generation und die 2x-Generation. Eine Arbeitshypothese.

Biol. Centralb., vol. 25, p. 97.

Lyon.

:04. The Evolution of Sex Organs in Plants. Bot. Gaz., vol. 35. p.

280.

McCLuNwc.

:02. The Accessory Chromosome — Sex ‚Determinant? Biol. Bull.,

. . Vol. 3, p. 43

MCCLURE

'92. Corn Crossing. ZU. Agric. Exp. Sta. Bull. 21.

MOENKHAUS.

The Development of the Hybrids between Fundulus heteroclitus

and Menidia notata with Especial Reference to the Behavior of

the Maternal and Paternal Chromosomes. Amer. Jour. Anat.,

vol. 3, p. 29.

MONTGOMERY.

A Study of the Chromosomes of the Germ Cells of Metazoa.

Trans. Amer. Phil. SSóc., vol. 20, p. 154.

MONTGOMERY.

Some Observations and Considerations upon the Maturation Phe-

nomena of the Germ Cells. Biol. Bull., vol. 6, p. 137.

MooRE, A. C.

The Mitoses in the Spore Mother-cell of Pallavicinia. Bot. Gaz.,

vol. 36, p. 384.

MOTTIER.

’97. Beiträge zur Kenntniss der Kerntheilung in den Pollenmutterzellen

einiger Dikotylen und Monokotylen. Jahrb. f. wiss. Bot., vol. 30,

p. 169

MOTTIER.

:03. The Behavior of the Chromosomes in the Spore Mother-cells of

Higher Plants and the Homology of the Pollen and Embryo-sac.

MRS: Bot. Gaz., vol. 35, P- 250.

MURBECK.

:Ola. Parthenogenetische Embryobildung in der Gattung Alchemilla.

Lunds. Univ. Arsskrift, vol. 36.

MURBECK.

:01b. Ueber das Verhalten des Pollenschlauches bei Alchemilla arven-

sis (L.) Scop. und das Wesen der Chalozogamie. Lunds. Univ

Arsskrift, vol. 36.

596 THE AMERICAN NATURALIST. (Vor. XXXIX.

MURBECK.

:02. Ueber Anomalien im Baue des Nucellus und des Embryosackes

bei parthenogenetischen Arten der Gattung Alchemilla. Zunds.

Univ. Arsskrift, vol. 38.

MURBECK. :

:01. Parthenogenese bei den Gattungen Taraxacum und Hieracium.

Botan. Not., 1904, p. 285.

NATHANSOHN.

Ueber Parthenogenesis bei Marsilia und ihre Abhängigkeit von

der Temperatur. Ber. d. deut. bot. Gesellsch., vol. 18, P- 99.

NAWASCHIN.

: Resultate einer Revision der Befruchtungsvorgänge bei Zilium

martagon und Fritillaria tenella. Bull. Acad. Imp. Sci. St.

Petersb., vol. 9, P. 377.

OSTENFELD.

:04a. Zur Kenntniss der Apogamie in der Gattung Hieracium. Ber. d.

deut. bot. Gesellsch., vol. 22, p. 376.

OSTENFELD.

/:04b. Weitere Beiträge zur Kenntniss der F ruchtentwicklung bei der

Gattung Hieracium. Ber. d. deut. bot. Gesellsch., vol. 22, p. 537-

OVERTON, E

'93a.

Ueber die Reduction der Chromosomen in den Kernen der Pflan-

zen. Vierteljahrssch. d. naturf. Gesellsch. Zurich, vol. 38.

OVERTON, E.

'93b. On the Reduction of the Chromosomes in the Nuclei of Plants.

Annals of Bot., vol. 7, p. 139.

OVERTON, J. B

: 02. Parthenogenesis in Thalictrum purpurascens. Bot. Gaz., vol. 33,

P. 363.

OVERTON, J. B.

: Ueber Parthenogenesis bei 77Ja/icfrum purpurascens. Ber. d.

deut. bot. Gesellsch., vol. 22. D. 274.

PRINGSHEIM.

"76. Ueber vegetative Sprossung der Moosfrüchte. Monatsber. d.

k. Akad. d. Wiss. Berlin, 1876, p. 425.

RAUNKIAER.

:03. Kimdannelse uden Befrugtning hos Maelkebótte (Taraxacum). Bot.

Tidsskr., vol. 25, p. ICQ

ROBERTSON.

:04. Studies on the Morphology of Torreya californica Torrey. Il.

The Sexual Organs and Fertilization. New Phytologist, vol. 3,

Pp. 205. .

ROSENBERG.

:03a. Das Verhalten der Chromosom

en in einer hybriden Pflanze.

Ber. d. deut. bot. Gesellsch.,

vol. 21, p. 110.

No. 464.) STUDIES OF PLANT CELL.-- VI. 597

ROSENBERG.

:03b. Ueber die Befruchtung von Plasmopara alpina (Johans.). Bihang

Hl K. Svenska Vet-Akad. Hand., vol. 28, Afd. 3, No. 10.

ROSENBERG.

:04a. Ueber die Tetradenteilung eines Drosera-bastardes. Ber. d.

deut. bot. Geselisch., vol. 22, p. 47.

ROSENBERG.

04b. Ueber die Reduktionsteilung in Drosera. Meddel. Stock. Hogs.

Bot. Inst., 1904.

ROSENBERG.

.05. Zur Kenntniss der Reduktionsteilung in Pflanzen. Bot. Notis.,

part I, 1905.

SADEBECK.

"79. Schenk’s Handbuch der Botanik, Breslau 1897. [An Account of

Apogamy in Ferns]. Vol. 1, p. 231.

SARGANT.

: The Formation of the Sexual Nuclei in ZZwm martagon. OR

Oógenesis. Annals of Bot., vol. 10, p. 445.

SARGANT.

'97. The Formation of Sexual Nuclei in Lilium martagon. II. Sper-

matogenesis. Annals of Bot., vol. 11, p. 187.

SCHAFFNER.

‚97. The Division of the Macrospore Nucleus (of Lilium philadel-

phicum). Bot. Gaz., vol. 23, p. 430.

SCHOENFELD. t

:01. La spermatogénése chez le taureau et chez les mammifères en

général. Arch. d. Biol., vol. 18, p. 1.

SCHREINER AND SCHREINER.

Die Reifungsteilung bei den Wirbeltieren. Ein Beitrag zur Frage

nach der Chromatinreduktion. Anat. Anz., vol. 24, p. 561.

Suaw.

'97. Parthenogenesis in Marsilia. Bot. Gaz., vol. 24, p. 114.

STAHL. :

76. Ueber künstlich hervorgerufene Protonemabildung an dem Sporo-

gonium der Laubmoose. Bot. Zeit., vol. 34, P- 689.

STRASBURGER. :

'84. Neuere Untersuchungen über den Befruchtungsvorgang bei den

= Phanerogamen als Grundlage für eine Theorie der Zeugung.

Jena, 1884.

STRASBURGER.

Ueber Kern- und Zelltheilung in Pflanzenreiche nebst einem Anhang

über Befruchtung. Mist. Beitr., Heft ı. Jena, 1888.

STRASBURGER.

The Peri

Life-history of Living Organisms.

odic Reduction of the Number of Chromosomes in the

Annals of Bot., vol. 8, p. 281.

598 THE AMERICAN NATURALIST. [VoL. XXXIX.

STRASBURGER.

'94 Ueber periodische Reduktion der Chromosomenzahl in Entwick-

lungsgang der Organismen. Biol. Centralb., vol. 14, pp. 817 and

STRASBURGER.

'5. Karyokinetische Probleme. . Jahrb. f. wiss. Bot., vol. 28, p. 151.

STRASBURGER.

'97a. Kerntheilung und Befruchtung bei Fucus. Jahrb. f. wiss. Bot.,

vol. 30, p. 351.

STRASBURGER.

'97b. Ueber Cytoplasmastrukturen, Kern- und Zelltheilung. Jahrb. i

wiss. Bot., vol. 30, p. 375.

STRASBURGER.

'97c. Ueber Befruchtung. Jahrb. f. wiss. Bot., vol. 30, p. 406.

STRASBURGER.

Ueber Biddkionetheliung: Spindelbildung, Centrosomen und Cil-

ienbildner im Pflanzenreich. Wist. Beitr., Heft 6. Jena, 1900.

STRASBURGER.

:00b. Einige Bemerkungen zur Frage nach der doppelten Befruchtung

bei den Angiospermen. of. Zeit., vol. 58, p. 293.

STRASBURGER.

:01. Ueber Befruchtung. Bot. Zeit., vol. 59, p. 353.

STRASBURGER.

Anlage des Embryosackes und. Prothalliumbildung bei der Eibe

nebst auschliessenden Erörterungen. Fest. z. zoth Geburtstag

Haeckel.

STRASBURGER.

:04b. Ueber Reduktionsteilung. .Sz/zéer. Akad. Berlin, vol. 18, p. 587.

STRASBURGER.

:04c. Die PER der Eualchemillen und allgemeine Gesichtspunkte

die sich aus ihr ergeben. Jahrb. f. wiss. Bot., vol. 41, p. 88.

STRASBURGER AND MOTTIER.

eber den zweiten Theilungsschritt in Pollenmutterzellen. Ber. 4.

deut. bot. Gesellsch., vol. 15, p. 327.

SUTTON.

:02. On the Morphology of the Chromosome Group in Brachystola

magna. Biol. Bull., vol. 4, p. 24.

an,

he Chromosomes in Heredity. Biol. Bull., vol. 4, p. Er

fuu.

'95. Die Betheiligung der Antipoden in Fällen der Polyembryonie bei

Allium odorum L. Ber. d. deut. bot. Gesellsch., vol. 13, p. 13-

TREUB.

98. L'organe femelle et l'apogamie du Belanophora elongata Bl. Ann.

Jard. Bot. Buiten., vol. ı 5p

No. 464.] STUDIES OF PLANT CELL.— VII. 599

TREUB.

:02. L'organe femelle et l'embryogénése dans le Ficus hirta Vahl. Ann.

. Jard. Bot. Buiten., ser. 2, vol. 3, p. 124.

TROW.

:04. On Fertilization in the Saprolegnieæ. Annals of Bot., vol. 18, p.

541.

WEBBER.

.00. Xenia, or the Immediate Effect of Pollen in Maize. U. S. Dept.

Agric., Div. Veg. Path. Phys. Bull. 22.

WILLIAMS.

:04a. Studies in the Dictyotacez. I. The Cytology of the Tetra-

sporangium and the Germinating Tetraspore. Annals of Bot.,

vol. 18, p. 141.

WILLIAMS. `

:04b. Studies in the Dictyotaceæ. II. The Cytology of the Gameto-

phyte Generation. Annals of Bot., vol. 18, p. 183.

WILSON. ;

:00. The Cell in Development and Inheritance. New York, 1900.

WINIWARTER.

.00. Recherches sur l'ovogénése et l'organogénése de lovaire des

mammifères (lapin et homme). Arch. d. Biol vol. 17, p. 33-

WINKLER.

:01. Ueber Merogonie und Befruchtung. Jahrb. f. wiss. Bot., vol. 36,

P- 753-

WINKLER.

104. Ueber Parthenogenesis bei Wikstremia indica (L.) C. A. Mey.

Ber. d. deut. bot. Gesellsch., vol. 22, p. 573-

WOLFE.

:04. Cytological Studies on Nemalion. Annals of Bot., vol. 18, p.

607.

NOTES AND LITERATURE.

NATURE STUDY.

Nature Study.'— Two little text books on nature study, designed

for use in the lower grammar school grades, give evidence of the

progress which has been made during the last decade in laying the

foundation for the teaching of the natural sciences. Too often in

our public and private schools a teacher is expected to give her

pupils *nature work," whether she herself is interested in the sub-

ject or trained for it. To such, if they have the gift of teaching,

these books should prove helpful. Dr. Overton's in particular can-

not fail to be stimulating to both teacher and pupil. It contains a

series of thirty-two lessons on various simple phenomena of plant

and insect life. Carter’s Nature Study with Common Things is

intended especially for city schools. It contains seventeen lessons

on material taken exclusively from plant life, either the fruit or that

part of the plant in which nutriment is stored. In the hands of an

unskilful teacher this course could easily become a burden to the

young pupil, inasmuch as it is limited to a field usually uninter-

esting to children. ‘The following quotation from Dr. Overton’s

preface brings out one point frequently overlooked in a discussion

of nature study; the italics are our own. " The object of nature

study," says Dr. Overton, *is not so much to get present knowledge

as to develop the power and love of observation by which knowledge

may be gained in after life."

RH.

1 Overton, Frank. Assisted by Mary E. Hill. Nature Study. A Pupils Text-

illus.

book. New York, American Book Company, 1905. 142

Nature Study with Common Things. An Elementary Labo.

Carter, M. H. ;

ratory Manual. New York, American Book Company, 1904. 150 pp. illus.

601

602 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

ZOOLOGY.

Wasps Social and Solitary.' — Rarely has such a fascinating

book as this on a given subject of natural history been presented to

the lovers of nature studies. So clearly and charmingly written, it is

a work from which all can derive pleasure and instruction. The

amount of time and patience required to obtain a knowledge of the

life habits of the various species can only be appreciated by one who

has attempted to work out a few species bearing indirectly on another

order of insects.

The varied habits of the wasps, from earth-diggers to wood-borers,

and from masons to paper-makers, give one every opportunity of

coming in contact with some of them during the many summer ram-

bles, and often to observe them under the most favorable circum-

stances. Their methods of paralyzing other insects and spiders

which they transport to their nests as food for their larve, suggests

both surgical and engineering skill ; equally interesting is the fact

that each species selects certain kinds of food for its progeny ; one

captures spiders only, another the larvae of Lepidoptera, a third flies,

and others beetles or bugs. “So strong and deeply seated is the

preference that no fly-robber ever takes spiders, nor will the ravisher

of the spiders change to beetles or bugs.”

The activities of the wasp are arranged under two groups: —

“Instincts and Acts of Intelligence, it being understood that these

classes pass by insensible stages into each other.” Under the first

are included stinging, the particular methods of attacking and par-

alyzing the prey, selecting the proper food, mode of carrying booty,

the general style of nest, spinning of cocoons, etc. To distinguish

acts of intelligence requires a familiarity with the normal conditions

of the insect. Such modifications of instinct as the adaptation of the

mud-daubers (Pelopzus) to the rafters and chimneys of buildings,

the Trypoxylon taking advantage of the straws on the face of a stack

that had been cut off smoothly, the hanging of spiders in a plant to

avoid the attacks of ants while searching for a nesting-place, the

occasional occupation by a queen Polistes of the previous year’s

comb instead of building a new one, the almost universal habit of

Bembex of closing the openings to their burrows when leaving, and

: P eckham, George W., and Elizabeth G. Wasps Social and Solitary. With

an introduction by John Burroughs. Boston and New York, Houghton, Miftlin

0,1 I2mo, xv + 511 pp, illus.

No. 464.] NOTES AND LITERATURE. 603

of Pompilus of enlarging its nest to accommodate an unusually large

spider, and of Ammophiles in seizing a small pebble in its mandible

and pounding down the earth over the opening to its nest, would all

come under the second group.

In summing up the chapter on the instinct and intelligence of

wasps, the authors who have so entertainingly presented the facts,

leave it largely to the reader “to determine whether the wasps are

wiser than they seem or seem wiser than they are.

GC. Wi].

Trouessarts' Catalogus Mammalium, Supplement.! — The great

activity of the last few years in discovering and describing new spe-

cies of mammals, living and fossil, has necessitated the preparation

of a *quinquennial supplement" to include changes and additions

made since the publication of the 1897 catalogue. The first three

fascicles of this supplement list the known living and fossil Primates,

Prosimiz, Chiroptera, Insectivora, Carnivora (Fasc. 1) ; the Rodentia

(Fasc. 2); the Tillodontia, Ungulata, and Sirenia (Fasc. 3). The

fourth fascicle will conclude the work and will contain an index. In

the preface the author states that the present supplement is intended

to summarize the state of our knowledge on this subject to date of

January 1, 1903, though in fascicle 3 certain new genera and species

described in 1904, are included without explanation, e. g., Nesohippus

Amegh. (p.635). In addition to listing the new forms, all the species

noted in the edition of 1897-99 are given in their proper place,

each with its serial number, but instead of the list of references fol-

lowing, there is added simply a number referring to the full quota-

tions for the species given in the former list, in cases where no

change has been made. A new feature introduced in the present

supplement is the citation of the full reference in case of generic

and subgeneric names. Footnotes and explanatory remarks are in

French, not in Latin as in the previous edition.

In general the compiler has made no attempt at revisionary work

so far as concerns specific determinations, but some care has been

used in replacing unavailable generic and subgeneric names with

new or later ones. ‘Thus, in including Matschie's revision of the

anthropoid apes, Trouessart does not repeat that author's error of

!Trouessart, E. L. Catalogus Mammalium tam Viventium quam Fossilium.

nd Supplementum, Anno 1904. — R. Friedlánder & Sohn, 1904-

905. Fasc. 1-3, 8vo, iv + 752 pp. 12 Mk. perf

604 THE AMERICAN NATURALIST. [Vor. XXXIX.

adopting Troglodytes as the generic name of the chimpanzee, but

unfortunately he overlooks the earliest available name, Pan, recently

revived by Palmer. Also, the authority for the specific name

of Gorilla gorilla should be Savage, not Wyman. Midas should not

have been used as a name for a mammalian genus, as it is preoccu-

pied among the Lepidoptera. The following new subgeneric names

are proposed for Primates: Pogonocebus to replace Diadema, Lep-

tocebus for Semnocebus, Maimon for Mormon, Promioclenus for

Mioclenus. Palmer has recently shown, however, that Mandril of

Voigt (1831) is available for Mormon, while the same author in 1903

proposed the subgeneric term Lophocebus to replace subgenus Sem-

nocebus.

In the determination of subfamilies, genera, and subgenera,

Trouessart frequently follows his own preference, and not always, it

would seem, to best advantage. Thus Pipistrellus and Lasionycteris

are regarded as subgenera of Vespertilio, and Dasypterus is placed

as a subgenus of Lasiurus, while two such closely allied forms as

Nycticeius and Rhogeéssa are nevertheless accorded their generic

rank. Artibeus is made to include Uroderma and Dermanura as

subgenera. Other instances might be multiplied.

Additional new generic and subgeneric names proposed are:

Jentinkia to replace Wagneria, Aymardia for Cynodon, Pagophoca

for subgenus Pagophilus, Orthegocerus a new subgenus of Capra.

The new family name Coendid is proposed instead of Erithizontide

for the New World porcupines.

Trouessart has made a laudable attempt to sort out so far as may

be the numerous new species of Muridz described in 1900 from

Chile by Philippi, mostly under the generic name Mus. One of

these names, “ Mus nemoralis,” thought by Trouessart to be an

Oxymycterus, is Preoccupied by Mus nemoralis Blyth, though this

seems to have escaped the notice of the compiler. Philippi’s “ Cer-

vus brachyceros” is similarly preoccupied and is renamed by Troues-

Sart, Odocoileus philippii.

The questionable practice of amending names leads the compiler

to change Tayassu to Tayassus since, he states, barbaric names

should be latinized. Nevertheless he rejects Dugong in favor of the

retal Halicore on the ground that the former is a barbaric name.

It IS a pity, however, that it is not possible to exclude such abnor-

malities as Guilielmofloweria or Carolozittelidæ !

. and Rekn’s list of North American land mam-

1 1901 (Proc. Boston Soc. Nat. Hist., vol. 30) was

No. 464.] NOTES AND LITERATURE. 605

unknown to the compiler. Comparison with this might have been of

considerable value and would have prevented, for example, the omis-

sion of Fiber osoyoosensis Lord, 1863.

. Considering the editorial difficulties presented by a work of this

nature, typographical errors are few. Several cases occur, however,

in which the prefix denoting fossil species only is inadvertently

applied in connection with living forms, e. g., Lama vicugna and

Trichechus manatus. 'The specific name of the capybara is mis-

spelled four times on p. 529.

The Catalogus gives evidence of laborious and painstaking work

throughout, and is indispensable to all working mammalogists. For

this reason, however, it is to be regretted that the price (12 Marks

per fascicle) is such as to place it beyond the means of many who

need it.

G. M. A.

( No. 463 was issued July 13, 1905.)

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THE

AMERICAN NATURALIST.

Vor. XXXIX. September, 1905. No. 465.

INTERRELATIONSHIPS OF THE SPOROZOA.

HOWARD CRAWLEY.

OTHER things being equal, it is perhaps an easier task to

determine the interrelationships of a group of parasites than

those of a series of free-living forms. Once the parasitic habit

is acquired, development is confined within narrow limits. Two

definite lines are followed. These are: morphological degrada- .

tion, and complication of the life history combined with increased

fecundity. It is perfectly evident why this should be. Individ-

ually, the parasite is at once relieved of two of the great prob-

lems of animal existence. These are: the obtaining of food and

the avoidance of serving as food for some other animal. The

parasite has no enemies and abundant food surrounds it on all

sides. As a result, various parts necessary to a free-living

animal are lost. These are: the organs concerned with the cap-

ture and digestion of food, and those which serve as protection

against the attacks of enemies. On the other hand, the new

mode of life involves new needs, and the organism responds by

the production of new organs. Such are: hooks, providing for

the maintenance of a fixed position, and, in many cases, beaks

or rostra which enable their possessors to bore through the tis-

sues of the host.

607

608 THE AMERICAN NATURALIST. [Vor. XXXIX.

Finally, a parasite acquires the ability to resist being digested.

This appears in some cases to result from the formation of a

differentiated external layer, but in general it is to be credited

to some property of the living protoplasm. It is, necessarily, a

property possessed by all organisms which live within others,

and hence has no taxonomic value.

But if the existence of the individual is rendered easier, that

of the species is menaced by a danger not experienced by free-

living forms. With these, birth, growth, and reproduction all

take place in free nature. For the most part, the eggs and

young are left to shift for themselves, but the dangers which

they encounter, are much the same as those which threaten the

adults. The greater mortality during these stages is primarily

due to their greater helplessness. But it is far different in the

case of parasites. For these the course must, so to speak, -con-

sist of a series of leaps. A given host, at best, eventually dies

and its death involves that of its parasites, as individuals.

Hence the eggs or spores must be transferred to another host

or else the species will cease to exist. Parasites are so abun-

dant, and so thoroughly well established that we are prone to

overlook what a radical departure this is from the ordinary

scheme of animal life. The elements destined to tide the spe-

cies over this critical period reach the exterior in one of several

ways. The more usual are either by the death of the host, or

by being carried out with its fzeces. Ordinarily animals do not

eat either their own dead or their own fæces, whence the only

chance the germ has is to become attached to the food and so

swallowed. Accordingly, as a general rule, parasites are com-

mon in social and uncommon in solitary animals. The termites,

which do eat their fzeces, invariably have their intestines literally

packed with the curious Trichonymphide.

The response of the species to this acquired peril is two-fold.

Complications are introduced into the life history. These are of

such a character as to increase the probability of obtaining lodg-

ment within the appropriate host. This is the most striking

feature displayed by parasites. The other response is the acqui-

sition of great fecundity. Great stress is always laid upon this,

yet it is after all doubtful if parasites, taken as a whole, do.

No. 465.) ZVTERRELATIONSHIPS OF SPOROZOA. 609

actually exceed other less specialized forms of life in their repro-

ductive powers. Nevertheless the germs are produced in such

numbers that if one in many thousands survive, the perpetuation

of the line is assured.

Examples in support of the statements given above are num-

erous. Certain animals, particularly the small Nematodes, live

indifferently either in the outside world or else upon or within

higher forms. Such may be regarded as upon the threshold of

the parasitic life. A second step is taken by those Flagellates

which inhabit the recta of frogs and salamanders. These ani-

. mals are morphologically like their free-living congeners nor is

their life history known to-be more complicated. But turning

to the flat-worms we find the parasitic habit in its most confirmed

aspect. This phylum, moreover, furnishes us with a series of

stages from typical free-living forms to typical parasites. It is

divided into three classes: the Turbellaria, the Trematoda, and

the Cestoda. The first class consists mainly of free-living ani-

mals, and is characterized by an alimentary canal and a ciliated

epidermis. The Trematoda retain the intestine, but have lost

the cilia. The Cestodes go farther, and losing all trace of an

alimentary canal, absorb their nutriment through the epidermis.

There is thus a progressive morphological degradation.

But along with this change in the individual, there is a strik-

ing change in the life history. In the free-living Turbellaria and

the ectoparasitic Trematodes, development is direct. That is,

the eggs produce young which grow to be adults without meta-

morphosis. On the other hand, the endoparasitic Trematodes

and the Cestodes bear off the palm for a complicated life history.

The organisms hatched from the eggs are wholly unlike the

adults, and there is always at least one metamorphosis. In addi-

tion, change of host is invariable. Thus, the liver fluke of the

sheep spends a part of its existence in a water snail. Indeed,

from a purely utilitarian standpoint, these animals appear to

have overshot the mark, and their ontogenetic: development

defies a rational explanation. The desired end could apparently

have been reached quite as certainly by less devious methods.

But while we cannot explain the raison d'étre for such processes,

it is evident that they indicate a confirmed parasitism. These

610 THE AMERICAN NATURALIST. [Vor. XXXIX.

animals are without doubt the descendants of a long line of para-

sitic ancestors and they probably represent the limit to which

the habit can go.

We are thus furnished with two criteria enabling us to gauge

the modifications induced by this mode of life. That is, given

two allied groups of parasites, that possessing the more degraded

organization and more complex life history is to be considered

as the less primitive. A third criterion is furnished by the part

of the host chosen fora habitat. Without doubt, the original

gateway was the mouth or the rectum. Thus the less modified

parasites are inhabitants of the alimentary canal. Examples are

such animals as Ameba blatte and the various Flagellates men-

tioned above, which dwell in the recta of frogs and salamanders.

Access to the lungs and liver is also easy, although some of the

parasites of the latter organ reach their chosen place by an

indirect path. In the case of the inhabitants of the sexual

organs, muscles, and brain, the infection comes in most cases by

way of the intestine. There is, however, no direct road and the

parasite must bore its way through the tissues of the host.

These parasites are generally of the most modified types. On

the contrary, the greatly modified Cestodes, at least in one of

their hosts, live in the alimentary canal. This criterion, then,

needs to be used with much more caution than the other two.

Having obtained certain criteria, I shall endeavor to apply

them to the matter in hand, as indicated by the title of my com-

munication. The Sporozoa stand alone. Their ancestors were

two rival views regarding their origin. Minchin ! aptly terms

these the euglenoid and the amoeboid hypotheses. The one

regards the Flagellates, the latter the Rhizopods, as the ances-

tral forms. Bütschli has advocated the former, whereas Min-

Chin pronounces in favor of the latter. To me, however, it

appears that neither can be adopted without reserve. Each,

by implication, assumes that all Sporozoa have had a common

14 Treatise on Zoölogy, edited by E. Ray Lankester, Chapter 1, Section K.

No. 465.] ZVTERRELATIONSHIPS OF SPOROZOA. 611

origin, which, for reasons that I shall give, does not appear to

be the case.

The class itself falls readily into two subclasses: the Telo-

sporidia and the Neosporidia. In the former, arrived at a cer-

tain stage of its existence, the individual divides into reproduc-

tive elements, the spores, and ceases to exist as an individual.

In the latter, vegetative growth and spore formation proceed

hand in hand. Further, the Telosporidia display sexual differen-

tiation of fully as definite a character as the mammals, while

nothing of the sort has as yet been described for the Neo-

sporidia.

The division into lesser groups is as follows : —

TELOSPORIDIA.

Order 1, Gregarinida.

Suborder 1, Schizogregarine.

Suborder 2, Eugregarine.

Tribe 1, Acephalina [Monocystidea].

Tribe 2, Cephalina [Polycystidea].

Order 2, Coccidia.

Order 3, Hemosporidia.

Suborder 1, Haemosporea.

Suborder 2, Acystosporea.

NEOSPORIDIA.

Order 1, Myxosporidia.

Suborder 1, Phaenocystes.

Suborder 2, Cryptocystes.

Order 2, Sarcosporidia.

Order 3, Haplosporidia.

This is Minchin’s classification, excepting the fact that I have

included the Haplosporidia. Doflein! rates the Coccidia and

Hzemosporidia as suborders, the two making up the order

Coccidiomorpha. This is probably an improvement,

1 Archiv für Protistenkunde, vol. 1, 1902.

612 THE AMERICAN NATURALIST. (VoL. XXXIX.

Of all the Telosporidia, the Polycystidea stand highest in

organization. Their name indicates the fact that they are

divided into parts. The division is longitudinal and the parts,

from before backward, are termed epimerite, protomerite, and

deutomerite. The epimerite is an organ of attachment, com-

parable to the suckers of Trematodes and the hooks of Cesto-

des. It is peculiar to the Polycystidea and has evidently been -

evolved to meet the requirements of an intestinal life. The

protomerite and deutomerite are the two “cysts” of the

gregarine body. The latter is nearly always much the larger,

and contains the nucleus.

From without inward, the ectosarc of a Polycystid gregarine

shows epicyte, sarcocyte, and myocyte. The epicyte is a mem-

brane of some formed substance. Its function is probably to

guard against the too rapid action of the fluids of the host's

intestine. The sarcocyte in protoplasmic and an ingrowth

from it forms the septum. which separates the protomerite from

the deutomerite. The myocyte is a muscular system of longi-

tudinal and transverse fibers. By means of various contractions

of these fibers gregarines are able to change shape and to dis-

play locomotor movements.

It is thus seen that as regards both form and anatomy the

Polycystids are somewhat complicated animals. They are also

exclusively intestinal parasites and there is neither change of

hosts nor alternation of generations. If then our criteria be of

any value, the Polycystid gregarines are the least modified of the

Telosporidia and stand nearest to the stem from which the

entire subclass originated. Assuming this as a working hypoth-

esis, it remains to be seen if the remainder of the Telosporidia

can be derived from them.

Grégarines develop from a minute protoplasmic body, known

as a sporozoite. The sporozoite is piriform or vermiform. At

the anterior end, the protoplasm is stiffened and forms the so

called rostrum, by means of which the organism is able to work

its way into an epithelial cell of the host's intestine. Asa rule,

penetration is only partial and the Polycystidea, with the excep-

tion of a single family (the Stenophoridz), are never cell para-

sites. In its chosen place, the sporozoite grows to be an adult

No. 465.] ZVTERRELATIONSHIPS OF SPOROZOA. 613

gregarine, or trophozoite. In most cases, the attachment to the

host epithelium is sooner or later lost and the gregarine takes

up a free life in the intestine of its host. In some species the

attachment is maintained until the animals are sexually mature,

but the distinction is not important.

Although lacking in secondary sexual characters, the adult :

gregarines are male and female. We owe this knowledge to

the recent brilliant work of Léger. At the proper period, two

of opposite sex come together, conjugate, and form a cyst.

Within the cyst, the male gregarine produces motile, tailed

elements, the spermatozoids. The female gregarine produces

rounded cells, the eggs. At maturity, the spermatozoids seek

and fertilize the eggs. Each fertilized egg eventually produces

a spore, the contents of which septate into eight sporozoites.

Ordinarily, the cysts reach the exterior shortly after their for-

mation, and sporulation takes place while the cyst is lying on

the earth. It may, however, be completed with the cyst still

in the host intestine, but auto-infection has never been described.

Eventually the cyst opens and the spores are set free. These,

if they reach the intestine of another individual of the host

species, dehisce and release the sporozoites. Otherwise their

fate is doubtless death.

In the classification given above, the Gregarinida are ranked

as an order. This order is divided into two suborders: the

Schizogregarine and the Eugregarine. The former includes

those animals originally termed the Ameebosporidia. They

possess a fixed body form, but their anatomy is much simpler

than that of the Eugregarine. There is an alternation of gen-

erations. So far, however, but four or five species are known,

and this rarity appears to be actual and not merely the result of

insufficient study. For the time being, it appears best to regard

them merely as a small offshoot from the Eugregarinze.

The Eugregarinz are divided into tribes. In the more recent .

general works, these are named the Cephalina and the Acepha-

lina. There does not seem, however, to be any good reason for

abandoning the older terms Polycystidea and Monocystidea.

Except for the interpolation of the Schizogregarines, this classifi-

cation is the same as that which has been in vogue for many years.

614 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

Its implication is that the relationship between the Polycystidea

and Monocystidea is very close. Relatively, this is true, yet

there are considerable differences. For one thing, reproduction

in the Monocystids is isogamous. The encysted trophozoites

each break up into gametes, which are allalike. These gametes

` fuse in pairs to form the zygotes. It is assumed that in each

zygote, one gamete has been derived from one trophozoite and

the other from the other, but the point is necessarily almost

impossible to demonstrate. Each zygote produces a spore.

In the second place, the Monocystidea are far simpler in

organization than the Polycystidea. While some of them

possess a definite body form, many do not. Moreover, as their

name indicates, their bodies are never divided into two chambers,

a result of the loss of the sarcocyte. It is on this same account,

in all probability, that they are polymorphic. Now, throughout

the Polycystidea a perfect series can be established based on the

development of the sarcocyte. In some it is always thick and

continuous all over the body. In others it is but feebly devel-

oped, while in a certain number the septum disappears, and these

species simulate the Monocystidea. The element is obviously in

a transitional state, and since we are dealing with parasites, we

are warranted in supposing it is disappearing.

Considering next the life history, the Monocystids, like the

Polycystids, develop from a sporozoite which is released in the

Intestine of the host. But whereas in the latter group the

SPorozoite never gets farther than the intestinal epithelium,

In the former it penetrates the coelome. Some Monocystids

develop in the connective tissue surrounding the intestines of

their hosts, whereas others go farther. Thus, in the Monocys-

tids of the earthworm, the sporozoites gain the seminal vesicles

before developing into gregarines.

We are thus furnished with certain data enabling us to deter-

mune which of these two groups is ancestral. The evidence

awards this distinction to the Polycystidea. That furnished by

the Sarcocyte is very suggestive, and the Monocystidea, which

lack It, are to be considered the derived group. The life history

points in the same direction. It is to be assumed here, as it is

in the case of most animals, that ontogeny recapitulates phy-

No. 465.] INTERRELATIONSHIPS OF SPOROZOA. 615

logeny. That is, the Monocystids have arisen from certain

sporozoites, which have pushed their way entirely through the

intestinal epithelium instead of remaining either attached to it or

within it. Finding in this way a congenial environment, they

have survived and eventually established a new group of animals.

It is thus possible to decide which of the two modes of repro-

duction displayed by these two groups is the more primitive.

On a priori grounds, heterogamy can be derived from isogamy

or isogamy from heterogamy. But, presumably, the more

primitive group will display the more primitive mode of repro-

duction. Whence the conclusion appears justifiable that the

lack of sexual differentiation in the Monocystidea is the result

ofaloss. This conclusion is supported by the fact that, in the

other Telosporidia, the organisms are male and female.

The life history of a Coccidian begins in precisely the same

way as that of a gregarine. A sporozoite, released in the lumen

of the intestine, seeks and penetrates an epithelium cell. From

this point, one of two courses may be followed. Easily satisfied,

the sporozoite may settle down at once within the cell it has en-

tered, and proceed to grow. Or else it may completely pass

through the intestinal wall, and eventually come to rest within a

cell of the liver, kidney, or testis. Ineither case, once established,

the organism grows until it reaches a certain definitive size.

Then, by a process termed schizogony, it divides into a number

of merozoites. These seek fresh cells, which they invade. The

schizogonous cycle, which may be repeated many times, occa-

sionally produces the parasites in such numbers that the host is

kiled. But whether or not, at the end of a certain time, the

ozoites develop into male and female cells. Each male cell

produces a number of minute elements, the microgametes. Each

female cell develops into a single egg, or macrogamete. At

maturity, the mobile microgametes. seek and fertilize the eggs.

Immediately after fertilization, the egg lays down a protective

covering and becomes an oocyst.

The process differs from that in the Polycystidea in two

respects. In these, the female trophozoite produces numerous

eggs and fertilization takes place within the cyst. In the Coc-

cidia, each female trophozoite metamorphoses into a single egg,

616 THE AMERICAN NATURALIST. [Vou. XXXIX.

and encystment follows fertilization. The attempts to homolo-

gize these two methods are not wholly satisfactory, and do not

shed much light on the relationship of the two groups. It may

be observed, however, that wherein the Coccidia differ from the

gregarines, they approach the conditions found in the highest -

animals.

Accordingly, in the attempt to derive the Coccidia from the

gregarines, it is advisable to seek evidence other than that fur-

nished by the reproductive processes. This is furnished by the

life history and the habitat. The Coccidia display an alterna-

tion of generations and live within cells. These are both indic-

ative of a greater specialization than is shown by the gregarines.

We may imagine that in evolution certain sporozoites penetrated

completely within the cells of the intestinal epithelium, and there

remained and developed. Such a habit, once acquired, would

speedily lead to morphological degradation. The Polycystidea

may almost be said to lead a free life. They possess and exert

the power to move from place to place. But the Coccidia, living

within cells, add to the degradation which follows from a para-

sitic, that which results from a sedentary habit. Two influences

are thus at work upon them, and they have become the most

simply organized of all the Sporozoa. Their form is spherical or

ellipsoidal, that taken by any non-living liquid when in a state

of equilibrium. Anatomically, they are merely nucleated masses

ef cytoplasm, not even displaying differentiation into ectosarc

and endosarc.

It then seems justifiable to derive the Coccidia from the Poly-.

cystidia, although perhaps indirectly, for reasons which I shall

give. The fact that some inhabit the internal organs of the

host presents no difficulty. In numbers, those infesting the

intestinal epithelium are much in excess. These were doubtless

first evolved. The intracellular habit once acquired, the organ-

infesting Coccidia could easily have arisen from those living in

the intestinal epithelium. The more venturesome sporozoites,

by passing entirely through the intestinal wall, finally gained one

of the internal organs. The pabulum furnished by a kidney or

testis cell being satisfactory, the line was established.

The last group of the Telosporidia is the Haemosporidia.

No. 465.] ZNTERRELATIONSHIPS OF SPOROZOA. 617

This order is, in some respects, the best studied of all the Spor-

ozoa, since it numbers amongst its members the parasites of

malaria and yellow fever. In the acquisition of two hosts, it

reaches a higher degree of specialization than the Coccidia, and

extreme specialization is also indicated by the relative paucity in

species. It is to be remembered, however, that from the bio-

logical side, the group is not so well known as either the Coccidia

or the Gregarinida. Accordingly, generalizations valid to-day

may need to be modified as our knowledge increases.

Two suborders have been established, the Haemosporea and

the Acystosporea. With the exception of one important fea-

ture, the life history of these two is the same. It is further

essentially the same as that of the Coccidia.

^ Asin the rest of the Telosporidia, the Haemosporidian begins

its career as a sporozoite. Set free in the blood of the host,

this sporozoite attacks and enters a blood cell, preferably an

erythrocyte. Here it grows into a trophozoite, which is amoce-

boid in the Acystosporea and generally vermiform in the Haemo-

sporea. The trophozoite, growing at the expense of the blood

cell, soon breaks up into a number of merozoites. By the dis-

integration of the blood cell, the merozoites fall into the blood

stream. Forthwith they attack new blood cells and the process

(schizogony) is repeated. The increase is therefore by geomet-

rical ratio and as Minchin says: “It is evident that reproduc-

tion at this rate could only continue indefinitely in the ichor of

an infinite host.” Accordingly, at the end of a certain number

of generations, the parasite provides for its future by the pro-

duction of male and female elements.

So far the process is exactly parallel to that found in the Coc-

cidia: In the Haemosporidia, however, or rather in the Acys-

tosporea, the male and female cells must be removed from the

blood of the host to insure further development. This removal

is effected by a blood-sucking insect (a mosquito) which takes

the parasites into its alimentary canal. Here they mature, the

male cells forming each a number of microgametes, the female

cells each a single macrogamete or egg. The microgametes

fertilize the macrogametes, which then metamorphose into

elongated elements, the oókinetes. The oökinete pierces the

618 THE AMERICAN NATURALIST. | [Vor. XXXIX.

intestinal epithelium of the mosquito and comes to rest in the

periintestinal tissue. There is first a period of growth, during

which the element assumes a spherical form and becomes

inclosed by a delicate wall. No actual cyst is developed.

Eventually, the sporozoites are produced directly from the

protoplasmic mass, the spore stage being omitted. Excepting

for the fact that fertilization is postponed until after the removal

of the parasite from the vertebrate host, that part of the Acysto-

sporean lite history which 1s passed in the mosquito corresponds

exactly to that part of the Coccidian life history which is passed

in the cyst.

The Acystosporea are parasitic in the blood of mammals and

birds. Intermediate hosts are known in many cases, and they

are.generally assumed in the rest. The Haemosporea, on the

other hand, infest reptiles and batrachians. Intermediate hosts

are not known,! nor can we readily believe that such forms are

much preyed upon by Diptera. However greatly we may dread

the mandibles of the mosquito, the Chelonia are probably indif-

ferent to its attacks. Moreover, in the case of Lankesterella of

the frog, it has been shown by Hintze ? that sexual reproduction

takes place in the blood, and that the motile zygotes so formed

gain the epithelium of the intestine. Here they encyst, the

cysts so formed eventually reaching the exterior by being

carried out with the fzeces of the host.

If the life history of Lankesterella may be taken as represent-

ative of that of the Hzemosporea, we find that the two sub-

orders of the Haemosporidia differ only in that the Acystosporea

have acquired an intermediate host. While this is indicative of

more extreme specialization, it is not difficult to imagine how it

may have been brought about. The warm-blooded vertebrates

have doubtless long been preyed upon by blood-sucking arthro-

pods. The crucial point in the bringing about of this change of

life on the part of the parasites was that some such blood-

sucker would be unable to digest them. This would be merely

a matter of chance. There was probably one time in their

! A case has, however, recently been described.

* Zool. Jahrb., AMA. f. Anat., vol. 15, 1902, pt. 4, p. 693.

No. 465.) ZWTERRELA TIONSHIPS OF SPOROZOA. 619

evolution when the Acystosporea could infect their vertebrate

hosts in two ways, but the intestinal method is now lost. The .

acquisition of an intermediate host is obviously advantageous to

the species, tending, as it does, to a wider distribution.

There are, however, anatomical differences between the

Hzemosporea and the Acystosporea. The former, in the troph-

ozoite stage, possess a definite body form, on which account

they are often spoken of as Haemogregarines. This definite

form is due to the presence of a dense hyaline ectosarc, in

which myocyte fibrille have been demonstrated. These ani-

mals, although typically cell parasites, indulge in frequent

migrations in the blood plasma, and during such “free” phases,

they display both contractile and locomotor movements. On

the other hand, the trophozoites of the Acystosporea appear

never to migrate. The blood cell originally attacked is aban-

doned only after the organism has divided by schizogony. No

special anatomical differentiation appears to have been described,

but the trophozoites undergo sluggish amoeboid movements.

Accordingly, as regards both the morphology and the life

history, the Acystosporea are clearly the more specialized

group. It next remains to relate the blood parasites with their

closest relatives, the Coccidia. :

As regards the life history, the parallelism is exact, except for

the acquisition of an intermediate host in the Acystosporea.

The sexual processes are practically identical. Morphologically,

however, the Coccidia are practically on a par with the Acysto-

sporea and considerably more degraded than the Haemosporea.

Comparing the Coccidia and the Haemosporea, the former would,

according to our criteria, be the derived group. But the favored

habitat of the Coccidia is the epithelium of the intestine, and it

seems as if this must have been occupied by Sporozoan parasites

before invasion of the blood.

The view advanced by Minchin seems best to fit the case.

This is that both Coccidia and Haemosporidia have arisen from

common ancestors. These ancestors in their turn I believe to

have been derived from the Polycystidea, and my conception of

the interrelationships of the Telosporidia is indicated by the

following scheme : —

620 THE AMERICAN NATURALIST. (VoL. XXXIX.

E ‘

Organ-infesting

Coccidia

Acystosporea

Intestinal

Haemosporea Coccidia Monocystidea

Polycystidea

The habitat of the Polycystidea, the intestine of their hosts,

has enabled them to lead a practically free life. Accordingly,

they are the least modified of all Sporozoa, and have retained

nearly as complex an organization as the Flagellates. They have

given rise, on the one side, to the Monocystidea and on the other

to the Coccidiomorpha. The former followed much the same

lines as their immediate ancestors, but have undergone morpho-

. logical degradation. The Coccidiomorpha became adapted to an

intracellular life, and separated into two groups. In one of

these, the inert Coccidia, morphological degradation has been

carried to its extreme. The greater anatomical complexity of

the Hzemosporea is to be credited to their habitat. The liquid

blood offers a radically different environment from the motion-

less epithelium. In consequence, the power to move, possessed

at the outset by the Haemosporea as an inheritance from their

Polycystid ancestors, has not been lost. Thus these animals

possess the characteristic Telosporidian organ of movement, a

myocyte. The Acystosporidia, further evolved, have apparently

lost the ability to move from place to place. Their inertness,

although comparable to that of the Coccidia, has been independ-

ently acquired. Finally, in their ability to display amoeboid

movements, they have not sunk quite so low.

Mesnil! considers the ancestral Telosporidian to be a Mono-

cystid intestinal gregarine. Minchin derives the group from a

hypothetical intracellular form. In both cases this ancestor is

supposed to have given rise to existing gregarines on the one

hand, and to the Coccidiomorpha on the other. To my mind,

1 Vol. Jubil. Soc. de Biol., Paris, 1899.

No. 465]. ZVTERRELATIONSHIPS OF SPOROZOA. 621

these hypotheses are open to objection in that they are based

almost exclusively on the reproductive phenomena. They both

involve the evolution of a more from a less complexly organized

parasite. I have endeavored to show that this is contrary to

what experience teaches us to expect. In our classification of

the Metazoa morphology is given first place and it should not be

. neglected in a consideration of the Protozoa. The remarkable

character of the reproductive phenomena displayed by the

Sporozoa has, I think, given them an undue importance. The

form of the adult animals has, in any attempt at a classification,

at least equal value. s

We have now to consider the Neosporidia. This subclass is

but poorly known. As shown above, it consists of three orders,

the Myxosporidia, the Sarcosporidia, and the Haplosporidia.

The Myxosporidia are characterized by their peculiar spores,

which bear a close resemblance to the stinging cells of ccelen-

terates. The spore consists of a bivalved shell, inclosing the

sporoplasm and the polar capsules. The polar capsules, of

which there may be from one to four, are tightly coiled filaments

which occupy vacuities in the spore substance. Acted upon by

the digestive juices of the host, the spore shell opens and the

filaments are everted. By means of these filaments the spore

is held attached to the intestinal epithelium of the host, and

the sporoplasm escapes as a minute amabula. Freed on the

surface of a host cell, it works its way within and comes to rest.

The nucleus presently divides, then the cytoplasm, and each

spore thus produces a number of bodies which are at least the

analogues of the Coccidian merozoites. They scatter through-

out the host and each gives origin to a trophozoite. The tropho-

zoite grows larger, becomes multinucleate and soon begins to

form spores. These, eventually reaching the exterior, are fitted

to infect new hosts.

The above outline of the life history is that given by Doflein.

It is to be observed that there is no sexual process. Doflein,

however, considers it possible that either the spores themselves

may conjugate very shortly after their escape from the spore

shell, or else that this process may take place between the young

trophozoites. This he advances merely as a surmise, there

being no observational evidence.

622 THE AMERICAN NATURALIST. (VoL. XXXIX.

The young trophozoite may follow one of several lines of

development. These lines diverge considerably. The nature

of the forms so produced is indicated in the following table,

which is taken from Doflein : —

Group I. Free-living forms.

Group II. Sedentary forms.

I. Inclosed in cysts.

2. In the state of *' diffuse infiltration."

3. Cell parasites.

Group I contains the most highly organized of the Myxospori-

dia. Its members lead a free life in the gall bladder, urinary

bladder, or kidney tubules of their hosts. They display differ-

entiation into ectosarc and endosarc. The latter is essentially

like that of other Sporozoa. The former is a clear granular

layer. It is the seat of motion and gives origin to the pseudo-

podia. A myocyte does not appear to have been described.

Throughout these animals resemble the Rhizopoda.

Group II is doubtless an offshoot from Group I, with the

exception of the cell parasites. The encysted forms are those

Which come to rest at some point within the host's body. The

part thus attacked reacts by the formation of a wall around the

parasite, which is thereupon prevented from extending its

explorations. * Diffuse infiltration " results when the parasite

spreads out through a considerable region of the host's tissues.

In such cases no cyst is formed. Eventually, these two kinds

of trophozoites die as trophozoites, but leave the tissues which

they had occupied, filled with spores.

The forms hitherto considered are mostly animals of consider-

able size, while the cell parasites, which belong to the suborder

Cryptocystes, are amongst the smallest of the Sporozoa. The

mode of life is, however, much the same. It is to this group

that belongs the destructive Nosema (Glugea) bombycis, the

cause of the silk-worm disease. |

In no Myxosporidian is an intermediate host known, and

infection is apparently always the result of chance. In those

forms which live in such places as the gall or urinary bladder, the

No. 465.] ZVTERRELATIONSHIPS OF SPOROZOA. 623

spores are assumed to reach the exterior with the evacuations of

the host. For the tissue-infesting species, however, there are

no natural channels. Where the parts attached are superficial,

it is conceivable that the tumors which so frequently occur in

Myxosporidian infection may break to the exterior. In this way

the spores would be set free. But in deep-seated infections the

conclusion seems inevitable that the death of the host is neces-

sary. This conclusion is supported by the fact that extensive

infections are generally fatal.

The Myxosporidia attack cold-blooded vertebrates and arthro-

pods. The Sarcosporidia confine their attentions to birds and

mammals. They are very abundant in the visceral muscles of

sheep and swine. While their spores differ from those of the

Myxosporidia, the animals themselves are morphologically a

good deal like those members of the last-named group which live

in cysts or in the state of diffuse infiltration. Additional data

regarding them are a crying need and at present all that can be

said is that they have probably evolved from Myxosporidian-like

ancestors. The Haplosporidia may be dismissed at once. Our

knowledge is too scanty to warrant any generalizations.

It is possible, however, to compare the Neosporidia with the

Telosporidia. Taking the free-living Myxosporidia on the one

hand, and the Polycystidea on the other, we fail to detect any

points of similarity. The habitats, life histories, and reproduc-

tive processes are wholly different. There is no morphological

likeness in any of the stages, from spore to trophozoite. Ina

few cases, gregarines are almost amoeboid and can protrude

pseudopodia. The Monocystids, also, are coelomic parasites and

some species live in the organic cavities of their hosts. But this

appears to be the sum total of the evidence indicative of any

connection between the two groups. It is palpably insufficient.

Unless, then, future discoveries of a fundamental nature shall

be made, there seems ample warrant for the view expressed by

Mesnil and Doflein. This is that the Telosporidia and Neospor-

idia are not genetically connected. Accordingly, at least for the

present, we should use the term Sporozoa merely as a convenient

cloak. It serves to cover certain Protozoa which cannot be

placed in any of the other Protozoan classes. It is not so long

624 THE AMERICAN NATURALIST. (VoL. XXXIX.

since the so called Vermes subserved a like function among the

invertebrates. Happily, in this case, confusion has been reduced

to order and we who are interested in the Protozoa may hope

that history will repeat itself.

WYNCOTE, PA.

CONTRIBUTION TO OUR KNOWLEDGE OF

THE MYXINOIDS.!

JULIA WORTHINGTON.

INTRODUCTION.

Ever since Johannes Müller introduced the Myxinoids to the

scientific world, interest in these primitive forms has continued

unabated, both as regards their peculiarities of structure and

function and their consequent position in the vertebrate series,

and the interrelations of the different varieties among themselves.

Owing to the wide geographical distribution of the Myxinoids,

the relative scarcity of individuals, and the difficulty of securing

material for study, especially the living animals, previous papers

have been based upon the study of museum specimens, and our

knowledge has, in consequence, been very incomplete. It was

my good fortune to obtain, during the summer of 1904, several

hundred individuals of Baellostoma dombeyi Lac. in sound,

healthy condition, which I kept alive in aquaria. I was able to

provide conditions closely approximating their usual habitat, and,

under these favorable circumstances, I kept them under con-

stant observation for four months. The observations made have

been checked by a study of the conditions of their normal habi-

tat. This paper, therefore, is based mainly upon a study of

living individuals in conditions approaching as nearly as possible

the normal environment; and these notes are published in the

hope of throwing some new light upon this interesting form, and

for the purpose of correcting some erroneous statements that,

through lack of means of observation, have gained currency.

I wish to express my thanks to Dr. C. H. Gilbert, of Stan-

ford University, who kindly placed at my disposal the facilities

of Stanford's seaside laboratory at Pacific Grove, California; to

1 Under the direction of Dr. Howard Ayers.

625

626 THE AMERICAN NATURALIST. [Voı. XXXIX.

Dr. Frank McFarland for helpful suggestions ; and to Mr. M. H.

Spaulding for much practical help. I wish also to thank Dr.

Michael Guyer, of the University of Cincinnati, for the loan of

laboratory materials, and to express my obligations to my sister

Louise for the very excellent and accurate drawings from which

the illustrations for Fig. ı and 2 were made.

The Myxinoid upon which the following observations were

made, is the common hagfish of the Pacific coast, Bdellostoma

dombeyi Lac. It is found in exceeding abundance in the Bay of

Monterey, where it is a great pest to the fishermen. It is

caught both with hook and line, and in traps. Those caught

on hooks do not live long in captivity. Instead of being hooked

in the jaw as is usual with other fish, Bdellostoma usually swal-

lows the baited hook whole, and is thus hooked through the head

or the body wall, hence the esophagus and stomach are more or

less torn in extracting the hook. Even under most favorable

conditions I have not found those caught on hooks to live

more than a few hours in aquaria. The traps used by the

fishermen in catching hagfish, are large wicker baskets, loosely

woven, resembling lobster pots. A quantity of bait, usually

pieces of squid or sardines, is put inside, and the trap sunk

over night. In the morning it may contain anywhere from

twenty-five to a hundred fish, mostly medium size, with a few

small and several large individuals. The largest hagfish are not

caught in the traps, as the meshes of the baskets used are too

small for them to pass through.

The aquarium, in which I kept them, was a wooden tank,

about six feet long, four feet wide, and two feet deep. It was

located in the basement of the laboratory, a large, cool room,

well lighted. The water in the tank was kept about a foot

deep, the bottom was covered with a thin layer of clean sand,

and stones were loosely piled in one corner to furnish hiding

places. Four streams of fresh salt-water, coming from glass

pipettes, with a length of stream varying from two to four feet

between the glass and the surface of the water, played con-

stantly into the tank, supplying fresh, well aérated water.

Here the colony lived throughout the summer. Although some

two hundred and fifty fish were thus kept under observation,

No. 465.] STUDIES OF MYXINOIDS. 627

not more than six or eight of the total number died a natural

death. Of these two hundred and fifty, about seventy-five were

kept in the aquarium from six weeks to two months or more

before I killed them, and more than a hundred were kept for

a month before being killed.

GENERAL DESCRIPTION.

It is not necessary to describe the general appearance or

characteristics of Bdellostoma, as that has already been admir-

ably done (Ayers, '94) ; but one or two poihts of interest were

ascertained in reference to their size. Of 550 specimens

measured, the longest was 24.5 inches, while 104 measured 20

inches or over, and 64 were between 19 and 20 inches long.

When it is remembered that of these 550 specimens, between

350 and 400 were caught in traps that did not favor the ingress

of the larger hagfish, the average length will be seen to fall in

the neighborhood of 19 to 20 inches. In regard to their length

at hatching, the smallest free-swimming hagfish that fell into

my hands measured scant two and three eighths inches (60

mm.), while a few days later I took an embryo from the shell

that measured a trifle more than two inches and a half (65

mm.). This embryo was apparently ready to hatch, as it swam

vigorously as soon as it was freed from the shell.

These newly hatched hagfish have the same shape as the

adult, the only perceptible difference between them and their

elders being that their tentacles are relatively a little longer

than those of the mature fish. At the time of hatching, the

head is an eighth of an inch in diameter; when from twelve to

fourteen inches long the proportions of head to body are some-

what different, the head measuring from three eighths to one

half inch across, and thus being relatively thinner. When

about fifteen inches long, however, the hagfish begin to increase

' rapidly in girth, measuring at least three fourths of an inch across

the head, while the larger ones measure still more. This

marked change of form does not, however, as might be thought,

mark the time of sexual maturity, for an individual only twelve

inches long and slim in proportion was found to have a well

628 THE AMERICAN NATURALIST. Vor. XXXIX.

developed ovary, with eggs in the process of yolk development.

In regard to the age at which these changes take place, we have

as yet no definite information. As is already known, the proc-

ess of development within the egg is slow, when compared with

the rate of growth of other vertebrate embryos ; and their post-

embryonic growth is probably also very slow, for very small fish

(viz. thirteen or fourteen inches long) kept in the aquarium for

three months, showed at the end of that time no perceptible

change in form or size, although they fed in a normal way, or

at least, as normally as any other fish in the aquarium.

One of the most interesting points about Bdellostoma, because

of its supposed taxonomic value, is the variation in the number

of gills. Taking the number found in the hagfish of different

geographic regions as a basis, the Bdellostomids have been

divided not only into different species, but also into different

genera, Bdellostoma forsteri, of the Cape of Good Hope, with

its six to seven gills on each side being placed in one genus, and

the Bdellostomas of the American Pacific coast in another, sub-

divided into two species, Bdellostoma dombeyi, with ten gill slits,

found in Chilean waters, and Bdellostoma stouti, whose usual

number of gill slits is eleven or twelve, in the waters of Cali-

fornia. Dr. Ayers ('94), after a careful comparison of the Cape

of Good Hope and California varieties, concluded that there was

no specific, far less generic difference between the two forms,

and stated that they, together with the Chilean variety, belonged

to one species, the preferable name for which was Bde/lostoma

dombeyi. This conclusion was scouted by Howes (94), but

purely on a priori grounds, and without any study of the forms

in question. Since this time not much work has been done that

would throw light on this question until within the last year or

two, when Dean, studying the hagfish found off the coast of

Japan, came across a variety that he called Homea okinoseana,

distinguished by having eight gills on each side, but in all other

respects like the hagfish of other localities. This Japanese

variety thus fills in the gap between the Cape form with its six

to seven gills, and that of Chile, with ten gills on each side.

It is worth while to study the California form carefully and in

detail with regard to the gils. Dr. C. H. Gilbert of Stanford

No. 465.] STUDIES OF MYXINOIDS. 629

University, quoted by Jordan and Evermann states that in fifty-

four specimens which he counted, forty-one had twelve gills on

each side, twelve had eleven gills, and one had thirteen gills.

He states also that he occasionally found one with ten or four-

teen on each side, but that the normal number was twelve.

Worked out in percentages, this would read : —

Individuals with 12 gills 75.0 %.

ex 11.8 222%

m “ 13 « 1.8 ob.

When tested by the examination of larger numbers of indi-

viduals, however, these figures undergo considerable modifica-

tion, and a new factor enters in, f. e., fish that have a different

number of gill slits on the two sides. The following table is

given by Dr. Ayers in his paper published in 1894 :—

101 individuals had 11 gill wey on both sides ;

26 moa ees * one side and

12 44 ow — s other ;

208 « “ I2 * * & both sides;

T “ “ 2 * & & one side and

Fi * " P Ihe other;

8 L “34 * «* e both sides.

354 total number of individuals counted.

Worked out in percentages this reads : —

Individuals with 11 slits on each side . . . 2857

u i an

iz. = " theothr . ‘ 293%

“ u 449 “© © ehade ' ^ . 58.7%

t « I2 « * one # and

HE . . -. 31%

e « yg *" * eachside . ‘ | 22%

These figures, as will be seen, reduce the percentage of those

having twelve slits on each side by one third, add very nearly

one third to the percent of those with eleven slits on each side,

increase slightly the percentage of those with thirteen on each

side, and introduce the two intermediate forms, those with

630 THE AMERICAN NATURALIST. [Voı. XXXIX.

eleven and twelve slits, and those with twelve and thirteen, these

two together amounting to 10% of the total number. Dr.

Ayers also says: “Of the eight 11-12 variation, where the

position of the gills was noted, four had eleven gills on the right

side, and twelve on the left, while the other four were just the

reverse, with twelve gills on the right side and eleven on the

left." On looking over the count of five hundred and fifty hag-

fish that I made while at Pacific Grove, I find still greater varia-

bility in the percents.

No. of No. of Gills

Individuals Left Right Percent

I 10 11 48

3 II 10 54

123 II II 22.36

25 II 12 4-54

44 12 II 8.

.325 i2 12 59.09

7 12 13 1.27

X IL 13 12 2.73

7 13 13 1.27

This larger count gives practically the same percentage of

individuals with twelve gills on each side as do Dr. Ayers’s fig-

ures, reduces that of those with eleven gills on each side about

one fourth, increases the sum of the 11—12, and 12-13 variations

from 10.4% to 16.5%, diminishes those having thirteen gills on

each side from 2.2% to 1.27%, "and introduces a new variation,

10-11 gills, this kind being .72% of the total number. This last

variation makes direct connection with the Chilean variety with

ten gills on either side. It will be noticed in my figures that

in the three uneven variations, 10—11, II—I2, 12—i3, the total

number of individuals having the larger number of gills on the

left side is sixty-two against thirty-three, almost two to one.

This point will be discussed a little later.

The table following combines the records of Dr. Gilbert and

Dr. Ayers with my own.

No. 465.] STUDIES OF MYXINOIDS. 631

1 o. of

Individuals Gills Percent

4 10-11 4l

236 II 24.63

95 11-12 9.92

574 12 59.92

33 12-13 3-44

16 13 1.67

A total of 958 individuals certainly gives a reasonably safe

number on which to base conclusions. In this table as in the

others, the fact stands out prominently that in the California

hagfish twelve gills on each side is the number most commonly

found. But when the number having it only amounts to 59.92%

in a total of 958 eels, it cannot well be called the normal, or even

the usual number, and consequently I agree with Dr. Ayers that

the usual number of gill slits is eleven or twelve.

That 13.7% in a total of 958 eels is found where the number

of gills is greater on one side than on the other, is to me one of

the most significant features in the proper specific classification

of the Bdellostomids. With six and seven gills the prevailing

number in Bdellostoma forsteri, eight in that found in Japan,

ten the number in the Chilean form, and eleven and twelve

in California, varying on the one hand, though rarely, to ten, and

on the other hand more frequently to thirteen, it is surely no

longer possible to divide these animals into different genera and

species on the basis of the number of gills alone; the count

of teeth (Ayers, '94), is equally unsatisfactory as a ground for

division into species, and no other ground for such division has

ever been advanced.

As a matter of fact, the differing number of gills in the

California hagfish is even more significant when the animal is

examined more closely, externally and internally, than when the

external apertures alone are counted. On dissecting the gill

region of those animals with an unequal number of gills on the

two sides, we find not merely that the number is variable, but

also where the variation is most apt to occur. Referring back

to my table, and noting the fish with an unequal number of gills

632 THE AMERICAN NATURALIST. | [Vor. XXXIX.

on the two sides, we find that the fish in which the greater num-

ber of gills lies on the left side (the side of the ductus cesophago-

cutaneus), occur about twice as often as those in which the greater

number is on the right side. But when the thoracic cavity of

these particular fish was dissected, I found several cases where

the number of external openings and the number of gills did not

correspond! Of the sixty-two individuals, in which the left gill

slits outnumbered the right, six had the last gill on the left side,

that which should open into the ductus, entirely wanting, mak-

ing an even number of gills on each side. Two of these six

were in the 11-12 group, four in the 12-13 group. In regard

to the position of the external openings only one was at the

normal distance from the ductus, in two the distance between

ductus and external aperture was one half the normal distance

between these openings, in two the external aperture lay very

close to the edge of the ductus, and in one it lay in the cephalic

edge of the ductus.

In other fish in which the number of gills on each side was

uneven, where the greater number was on the left side, five had

the last gill, that which opens into the ductus, rudimentary, vary-

ing from one fifth to one half the size of the normal gill, and in

one of these the opening of the ductus was one half the usual

distance from the external aperture nearest it.

In all of the fish examined by me that had the greater num-

ber of gills on the right side, the gills were normal, and nor-

mally placed. But another curious variant was found in the

12-11 series that has a marked bearing on the question, whether

the change in the number of gills in the different varieties is

due to addition or suppression. This individual had twelve gills

on the left and eleven on the right side. The twelfth gill was

of normal size and at a normal distance from its neighbor, but

the second gill on the left side (counting from before backwards),

was missing, the external opening leading into a short cul de sac.

The first gill on the same side was rudimentary. If there were

1 It should be stated here, that in counting gill slits, 7. z., the external apertures,

the external opening of the ductus cesophago-cutaneus is always counted as one,

as the external aperture of the last gill on that side usually lies not on the outer

surface, but in the ductus just inside the opening.

No. 465.] STUDIES OF MYXINOIDS. 633

either a fixed or a normal number of gills, this could only mean

that this particular animal was a freak. But where we have

variations of the species in which the number of gills ranges

from thirteen to seven, and one variation (that from California),

in which no number can be considered either normal or fixed,

and where the last gill on one side is found to be either rudi-

mentary or missing, there is certainly an indication of a ten-

dency to the suppression of the gills. Moreover, in the last

case the rudimentary and the missing gill are both in an unusual

place (the cephalic instead of the caudal end of the line). Still

another variant bears out this view. This variant was one of the

even-numbered group, with twelve gills on each side. On open-

ing the thoracic cavity, it was found that while the fish had

twelve normal gills on the right side, on the left the first was

missing, and the second rudimentary. As in the case last men-

tioned, the external aperture of the missing gill led into a cu/ de

sac and there was no pharyngeal opening. In this fish there

was no external mark to indicate the slightest abnormality

within, which raises the question : What percentage of abnor-

mality would be found if careful dissection were made of the

gill regions of a large number of individuals?

There is no particular size in which these variations occur. In

the last one given, the fish was only eleven and one half inches

long ; in the one preceding, twenty-one and one half inches long;

the others varied between these two. It would be interesting

if some young hagfish with an uneven number of gills, particu-

larly individuals where the distance between the ductus and the

nearest gill is less than normal, could be kept under observation

for a number of years, to see if any changes occur during the

life of the individual, or if these variations are fixed during

larval growth and remain fixed during adult life. It would also

be of great value in this connection if the other varieties of

hagfish could be more carefully studied, to determine if the vari-

ation in the number of gills is as great as that of the California

hag, and if so, when the variations occur. It should also be

determined whether the number is more constant among the

groups having a small number of gills.

634 THE AMERICAN NATURALIST. (VoL. XXXIX.

HABITS AND HABITAT.

The hagfish abounds in the Bay of Monterey, and is taken on

the regular fishing grounds, particularly on the rock-cod beds, at

a depth of about three hundred feet. The bottom here is rocky

and coated with a thin, smooth sediment, but without any great

amount of sand or seaweed. Infrequently it is captured in

shallower waters along shore where the bottom is sandy. From

observation of several hundred individuals, I find that in the

aquarium they evidently prefer the hard bottom when at rest/*

lying for the most part coiled in and out among the rocks, some-

times with their heads under cover, but more often with about

two inches of the head projecting freely into the water. "When

not among the rocks, or not swimming, they rest coiled up on

the bottom of the tank (Fig. 2), occasionally resting on the sand,

but more often on the wood where the sand has been pushed

aside. Ata time when there were about thirty fish in the tank,

I kept watch fora week to see how many chose the different

kinds of bottom. I transcribe here the notes taken at the

time.

July 24, A.M. All were among the rocks but two. Of these

two, one was curled entirely on the wood, the other curled on

the wood with its head resting on the sand.

July 24, P.M. Two were lying entirely on the wood, the rest

were among the rocks.

July 25, Noon. The same as on the previous day. After

pouring water on them vigorously, and so stirring them up to

swim around, six settled finally on the wood, two of them with

their heads resting on the sand, while the others returned to the

rocks.

July 26, Noon. Two were on the wood, the rest among the

rocks.

July 26, P. 4. All were among the rocks.

July 27, A.M. Two were on the wood, the rest among the

rocks.

July 28, Noon. One on the wood, the rest among the rocks.

vi 29. Two on wood, one on sand, the rest among the

rocks.

Fic. 1.— Hagfish coiled among the rocks. X m

636 THE AMERICAN NATURALIST. | [Vor. XXXIX.

July 30, A.M. Three on wood, one of them with its head

touching the sand, the rest among the rocks.

July 30, P. m. Five on wood, the rest among the rocks.

Aug. 1, A.M. All among the rocks.

Aug. ı, Noon. Five on the wood, two of them partly touch-

ing sand, the rest among the rocks.

* Fic. 2.— Hagfish at he t Eeh

of the aquarium. Natural size.

At a later date when there were one hundred and thirty fish

in the tank, two more observations were made. The first showed

only sixteen of the hundred and thirty fish on the sand, the

second only fifteen. A few days later with one hundred and

twenty-four fish in the tank, only twelve were on the sand.

Unquestionably then, in the ordinary circumstances of life,

the hagfish prefers a hard bottom to rest on. If the rock heap

No. 465.] STUDIES OF MYXINOIDS. _ 637

is overcrowded, and the bare wood spaces preémpted, those left

out will, for the most part, gather together and form a tangled

coil, looking much like the conventional Medusa’s head.

Perhaps another factor entered into this consideration of bot-

tom, however. Was it altogether a feeling of touch that gov-

erned their choice of resting place, or did color play a part?

Did they prefer the dark to the light ? Two hagfish were trans-

ferred to an ordinary aquarium with glass sides and a zinc bot-

tom. Half of this bottom was covered with sand to the same

thickness as that in the large tank, and the sand and zinc were

nearly the same color. The fish were kept here for several

weeks, and acted just as they had in the large wooden tank.

They coiled persistently on the hard zinc bottom, against the

side of the aquarium, or against the iron waste pipe, seldom

being found on the sand. After a few days I put a rock in the

midst of the sand bottom, and after that one or the other would

be found lying against it, but otherwise they shunned the sand,

showing that it was purely a sense of touch that guided them.

The hagfish seem to have great power of resistance to unnat-

ural environment, judging by the way they are handled by the

Monterey fishermen, and the condition in which they reach the

laboratory. Theyare taken from the traps between six and ten

o'clock in the morning, dumped, fifty of them together, into an

oblong can with a base about ten inches square and sides per-

haps eighteen inches high, barely covered with water, and then

stowed somewhere in the bottom of the boat while the fisher-

man finishes his business and rows to shore, a distance of two

orthree miles. Arrived on shore, they remain sometimes for

several hours in the same uncovered cans before transportation

to the laboratory. At the laboratory they undergo one more

handling, as they are counted on being put into the aquarium.

But in spite of this long wait in very little, poorly aérated

water, but few die, though they are greatly crowded, and some-

times roughly handled. The long exposure to the air likewise

seems not to affect them if the weather be not too warm, and

the can not too full, so that the sun does not strike directly

upon them. Of the first catch of about fifty, all lived ; and of

the second of one hundred and thirty-two, brought up in two

638 THE AMERICAN NATURALIST. [Vor. XXXIX.

cans, thirty or forty were sick on arrival, but the next morning

two only were dead, and all the rest in fine condition. It is

noticeable that the young ones have, as a whole, more power of

resistance than the old ones, for they would arrive fresh, as

though just from the depths of the bay, no matter how sick

many of the older ones were.

There is one unfailing test of the general condition of the

hagfish : its geotropic reaction. When well and at rest, it is

invariably coiled up more or less tightly, either in a spiral by

itself (Fig. 2) or in and out among the rocks. Even if the fore

part of its body lies free and sinuous, the tailis coiled. But if

exhausted or sick, the coil straightens out, and it lies in a cres-

cent form. The sicker it is, the straighter it becomes, and

when dead it lies entirely straight,

The hagfish can live out of water without injury for a great

many hours if kept in a cool, damp place. I often found on

visiting the tank in the morning, that one or more of the

smaller fish had found the water outlet while swimming in the

night, and had slipped to the floor. They would be tightly

coiled on the cool, moist cement floor, and were as agile and

active there as in their native element.

There is one condition, however, that the fish cannot endure:

a rise in temperature. The water on the surface of the Bay of

Monterey averages in summer 64? F. or 17.7? C. What it is

at a depth of two hundred feet, I do not know, nor how cold it

gets in winter. But the air at Monterey is never so cold as to

kill palms or heliotrope, so the water cannot become very cold.

The water in the tank in which I kept the fish averaged 22? C.,

and in that they throve. On a warm sunny morning, I placed

two young hagfish in a tank about three feet long by one foot

wide, covered them with about five inches of fresh salt water at

ae Gu and placed the tank by a window, where the sun shone

directly into half of it, leaving the other half of it shaded.

Under the heat of the sun the water in the tank rose gradually

to 30° C. As the water became warmer, the fish grew very

restless and languid, swimming constantly, not rapidly as usual,

but with a slow, jerky movement as though seeking to escape

the warm water. At the end of two hours and a half one of

No. 465.] STUDIES OF MYXINOIDS. 639

them was lying almost straight. Both were put into the small

aquarium with running water at a temperature of 22? C.; they

swam freely for a few minutes, then settled down against the

outflow pipe, having regained their normal habit. This was

between half-past twelve and one o’clock. It was an exceed-

ingly warm day, the thermometer standing at 89°F. in the

shade, and the aquarium was so placed that the afternoon sun

streamed directly upon it. About five o’clock I noticed that

the two hagfish were very languid and stretched almost straight.

On testing the water I found that it had risen to 29° C. Sud-

denly, the hagfish, without anything being done to disturb them,

began to swim in a very violent, jerky way, and to throw out

strings of slime, which is never done except when they are

irritated. They would swim and stop intermittently, always

lying at full length when at rest, and swimming so irregularly

and violently as to injure themselves. When put into cooler

water, 22? C., they immediately settled down quietly, half

stretched out. I placed them in a small wooden tank in the

cellar, by the large tank, in order to keep them separate from

the other fish for a while, and note what after-effects there

might be. The next morning one of them had escaped to the

floor, together with two from the large tank. Of these three,

two were entirely normal, and one was dead, in all probability

the one that had been exposed to the heat the day before. The

other hagfish grew steadily more languid, and died at noon the

next day, two days after the experiment. Both fish were in a

normal condition when the experiment began. It was positively

the heat from which they suffered, and not the actinic rays,

because they had been exposed to brilliant sunshine every after-

noon for a month, and no ill effects had followed. The day

they were affected was the first day there had been a marked

rise in temperature.

Taken as a whole the hagfish do not lead an active life.

When thoroughly aroused and on the alert, they swim at a very

high speed, with a graceful, serpentine motion, but for the most

part, they lie placid, perhaps motionless, perhaps lazily moving

their heads from side to side. They are more active by night

than by day. In the daytime more than once I found some of

640 THE AMERICAN NATURALIST. | [Vor. XXXIX.

them asleep. There was no outward difference between the

sleeping ones and the others; all were curled quietly on the

bottom, but if by chance a sleeping one was touched, instead of

wriggling away it remained passive, unless perchance it coiled

tighter, retaining its coil even when lifted from the water.

Once I found two sound asleep, surrounded by a mass of slime

in which they had in some way become lodged. The slime

served them as a buoy, and they were floating quietly in it on

the surface of the tank, circling around with the current. I

took them out and stripped their covering from them, but they

hardly aroused while I did so, and settled down to sleep again

as soon as they were put back into the tank. Sometimes after

a minute or two of handling they awake, but an interval elapses

between their first stirring when they squirm uneasily in the

hand, and full alertness when they swim rapidly away, or if

held tight, they make the usual vigorous efforts to free them-

selves. If before the fish is wide awake, it is put back gently,

it can drop off to sleep again. I once lifted a sleeping fish,

dropped it into a pail, carried it a distance of more than two

hundred feet, took it out of the pail, and started to decapitate

it. All this motion followed by the tight grasp of my hand and

the first touch of the shears, usually the first signal for the

most frantic struggles, did not rouse it perceptibly, and its head

was off before it began to squirm.

It is interesting to watch their movements, while they are

becoming accustomed to confinement. When the first lot of

fifty were placed in the tank it contained only water. They

were normal fish in every respect and when first placed in their

new home they swam around very vigorously, threw out a great

deal of slime when touched, and were on the whole, unusually

excited. After a short while, they settled down on the bottom,

in the usual coils (Fig. 2), an occasional group of three or four

together, the rest separate. Two days later sand was put on

the bottom, and the rock pile built at one side.

In a few hours

all had burrowed among the rocks.

] There they lived very

quietly, seldom moving when left to themselves, except at night.

F or the first four or five days they were easily aroused by

dipping a small pailful of water from the tank and pouring it on

No. 465.] STUDIES OF MYXINOIDS. 641

them. When this was done they would throw out great quan-

tities of slime, and wriggle among the rocks, some of them

leaving the nest, and swimming rapidly around the tank.

When the sixth day came it was harder to rouse them, and for

about ten days following they could hardly be stirred, neither

throwing out slime nor swimming when the water was troubled.

If one was lifted on a stick and moved, it quickly settled down

wherever it might. be, finding its way back to the rocks later.

This was not due to illness, for their positions were normal.

Toward the latter part of the third week, they became more

active, lying quietly in the rocks when undisturbed, but rousing

easily and getting much excited when water was poured on them

from a pail, swimming freely and throwing off slime again, as

they had done at first.

The second lot I received went through the same stages of

liveliness and torpor as the first, and in about the same time

intervals;

The so called slime they throw off is their chief means of

protection. It often enables them to escape from whatever

would catch them, by forming a covering so slippery that it is

difficult if not impossible to get or keep hold of them. The

thread cells are not emitted except upon sufficient provocation.

I have often lifted. them carefully and had them slip through

"my fingers without causing thread cells to escape. It is their

response to conditions that irritate; they are always thickly sur-

rounded with slime when caught on the hook, and the occasional

ones that died natural deaths in the tank had always thrown off

a considerable amount of slime in dying.

The question of what and how the hagfish eat, is one that

has been much discussed in previous papers about them, some

writers maintaining that they are parasites, and all stating that

they are extremely voracious. In regard to this latter point the

evidence comes from the fishing grounds. When the night lines

are examined, one third or more of the hooks hold hagfish and

the fish on many of the others have been entirely eaten away,

nothing but the skin and bones being left. The hagfish has

bored inside the skin and eaten all the soft parts, and is some-

times caught in the very act of wriggling away at the close ”

642 THE AMERICAN NATURALIST. | [Vor. XXXIX.

its meal when the fish is taken from the water. From what I

saw of their behavior in the tank, though, I conclude that this

behavior shows the inordinate numbers of the fish in the bay,

rather than extreme voracity. Those.that I had were small

feeders, and went a long time without eating. Asa matter of

fact, they ate so infrequently that I was not able to experiment

with them and test their likes and dislikes as much as I wished.

According to the fishermen, the best bait is squid ; failing that,

they use herring, or as they call them, * sardines."

My first lot was caught on a Friday. The following Monday

I put into the tank eight dead flounders about ten inches long

and three inches wide. About a dozen of the fifty hags ate

freely, some of them ravenously. But although several of the

flounders had been partly eaten, the total consumed did not

amount to more than two flounders. :

It is very interesting to see them eat. The process may be

easily watched when they are fed with small fish, or are just

beginning on a large one. The feeding apparatus, described by

Ayers and Jackson (:00), consists of a heart-shaped plate com-

posed of symmetrical halves that open out and fold together

like the leaves of a book. This plate bears on the dorsal sur-

face of each half a double row of horn teeth, their points

directed meso-caudad, and itlies imbedded in the membrane of

the ventral wall of the pharynx.

When the animal feeds, the tooth plate, which is really a mod-

ified and movable lower jaw, and in no sense a tongue, as stated

by Müller (34) and P. Fürbringer, is thrust out of the mouth,

and its fore end is drawn down so that it takes a position almost

perpendicular to the long axis of the body. The two halves

are at the same time drawn apart, so as to present an almost flat

surface. Placing this flat surface against the fish to be eaten,

the hag draws the halves of the tooth plate together, thus tear-

ing off a portion of the food, and then withdraws it into its

mouth. It swallows the food very rapidly, and immediately

eee out the tooth plate for more. There is no sucking motion

= Fürbringer has said; the hagfish simply rests with its nose

against the fish, and if, because of a current in the water, or

through the vigor of the attack, the food is moved from its

No. 465.] STUDIES OF MYXINOIDS. 643

position, the hagfish swims rapidly after, keeping in this way in

constant touch with it.

This tooth plate is worked by five muscles, three of which

form a unique mechanism called by Dr. Ayers the “ club.”

These muscles lie close to the ventral surface and may all be

seen when the ventral skin and body musculature are deflected

back. The two that do not belong to the “club,” lie ventro-

cephalad of it (Fig. 3). The more lateral one arises as a narrow

Fig. 3, Fig. 4.

Fic. 3.— The “club muscle” and its accessories. Ventral view. 2. £., basal plate; c. m.,

circular muscle; Z. »r., long muscle; 7. m., perpendicular muscle. 4 natural size.

Fic. 4.— The “ club muscle" and it ories. Lateral view. Half of the circular muscle

has been cut away in order to show the long muscle. ¢. m., circular mu

muscle ; 2. mz., perpendicular muscle; 7 ?., tooth plate. 4 natural size.

scle; 2. m., long

band of fibers along the lateral edge of the cephalic half of the

caudal section of the basal plate, runs cephalad, then curves

slightly mesad, joining its fellow of the opposite side in a com-

mon aponeurosis, about a quarter of an inch behind the mouth

opening. The aponeurosis continues forward until it reaches

the mouth opening, where it fuses with the connective tissue

which supports the mucous membrane of the lower lip; here it

divides, each half deflecting posteriorly and laterally, to attach

itself near the cephalic border of the tooth plate. The contrac-

tion of this muscle helps the two halves of the tooth plate to

close together.

644 THE AMERICAN NATURALIST. [VoL. XXXIX.

This mandibular muscle (Figs. 3, 4), is called by Fürbringer,

m. copulo-glossus superficialis, and by Müller, * der oberfläch-

licher Vorzieher der Zunge.’ Both of these names are now

inadmissible, as we are dealing with the lower jaw and not with

the tongue as these authors thought.

Mesad of this superficially placed mandibular muscle lies

Fürbringer's m. copulo-glossus profundis, Müllers “tiefer

Vorzieher der Zunge." This muscle (Figs. 3, 4), consists of a

lateral and a mesial division which join together at the cephalic

end. The lateral division arises from the lateral edge of the

caudal end of the third section of the basal plate. Its fibers

run laterally, then curving, run cephalad along the border of the

mandibular muscle last mentioned. The mesial division also

arises from the lateral edge of the third section of the basal

plate, between the points of origin of the lateral division of this

muscle and the superficial mandibular muscle. It runs forward

between the lateral division and its fellow of the opposite side,

being separated from the latter merely at its hind end. The

combined mesial and lateral divisions of each side fuse together

at the cephalic end into a common tendon for the two muscles.

This tendon runs cephalad between the basal plate and the

aponeurosis of the superficial muscle, turns dorsad at the cephalic

end of the latter, and runs caudad to the tooth plate where KC

divides again and is inserted midway in the length of the latter,

close to the median line. This muscle, by contraction, draws

the tooth plate forward, and by contracting to its full extent

pulls it out of the mouth and into the vertical position.

The other three muscles that manipulate the tooth plate form

a structure aptly named by Dr. Ayers the “club muscle." This

“club” is between three and four inches long and consists of

a hollow circular muscle, a long muscle, and a perpendicular

muscle.

Of these three, the long muscle (Fürbringer's m. longitudinalis

linguæ, Müller’s “innere Längsmuskel der Zunge”) is the only

one zb direct connection with the tooth plate. This long muscle

(Figs. 3, 4, Z. m.), is about three inches long, and from half to

three quarters of an inch across its caudal end, tapering at its

cephalic end to two tendons, one of which lies enclosed within

No. 465.] STUDIES OF MYXINOIDS. 645

the other. These two tendons run cephalad to the tooth plate,

just before reaching which they separate, the outer tendon

attaching itself to the ventral surface of the tooth plate along

the median line, the inner one dividing into two which curve

laterad, run ventrad of the plate, and insert near the lateral.

border. The fibers of the long muscle are directed longitudi-

nally. Shortly before reaching the caudal end, they separate

into two divisions, permitting the passage between them of

the perpendicular muscle. They curve around this, curve mesad

toward each other, and end in a thin fascia that forms a partition

between them. When this long muscle contracts, it draws the

tooth plate back into the mouth, and then flattens it out again.

But as the long muscle is fixed only at one end, it cannot con-

tract without assistance, hence the perpendicular and circular

muscles.

The perpendicular muscle (Müller's “innere senkrechte

Muskel der Zunge”), is a short rather stout muscle, arising

from a small cartilage on the ventral surface of the *' club,"

and running cephalo-dorsad, where it ends in a bounding fascia

(Figs. 3, 4, P. m.). This little muscle, surrounded as it is by the

long muscle, acts as a fixed point for the latter to contract

around, and by contracting itself, increases its diameter as a

pillar, and by thus taking up more room, helps the other to con-

tract.

The circular muscle, also one of the mandibular muscles

(Fürbringer's m. copulo-copularis, Müller's *hóhler Aussermus-

kel der Zunge "), is a hollow cylinder surrounding the long mus-

cle (Figs. 3, 4, c. m.). It begins about a quarter of an inch caudad

of the tooth plate, and continues to within half an inch of the

caudal end of the “club.” It is much thicker at its cephalic

end, where the long muscle consists of little more than a tendon,

than at the caudal end, its walls growing thin there, and the long

muscle increasing in girth. It is covered with an aponeurosis

into which its fibers are set. Its fibers run circularly at right

angles to the long axis of the “club.” In cross section the

walls of the circular muscle are seen to be crescent-shaped,

thick on the ventral surface and at the sides, but thinning as

they proceed dorsad, until only a thin layer or fascia is left to

646 THE AMERICAN NATURALIST. [Vor. XXXIX.

close the cylinder upon its dorsal surface (Fig. 4). The circu-

lar muscle by contracting around the long, forces it back to

where it has more room in the hind end of the * club," and so

helps it to withdraw the tooth plate. Considering the extreme

cumbersomeness of this device for using the lower jaw, it is

rather remarkable that the hagfish can move it with the light-

ning-like rapidity with which it does.

If the fish is large enough to permit of it, the hagfish makes

only one opening in the skin, and pushing in through that,

. works its way around inside, eating as it goes. I have seen

three hagfish attack one fish through the same opening, their

heads entirely hidden in the fish's body, their tails flapping like

streamers in a wind as they pushed the fish in front of them,

each striving to outdo its neighbor. They usually eat together,

and I have often seen several of them at work on one dead fish,

while other fish would be lying untouched in the aquarium.

Under these circumstances it is no longer permissible to hold

that the large fish found to be reduced to skin and bones, have

been thus denuded by a single hag, though it may well be that

only one of the number is detected in the act of leaving it.

The hagfish do not eat often. After the first feeding in cap-

tivity, a week passed before they were given anything more.

Then flounders were given again, but only half a dozen ate. A

week later, when flounders were offered them for the third time,

only three touched them. At the end of another week they

were given a rock cod, but did not touch it. Four days after,

they were given a small cod and two small flounders, but did

not touch them. It was not that the food did not suit them,

for they eat any fish on the lines; they were evidently not

hungry. StillI thought I would see if a different kind of food

would tempt them more, so the next week, thirty-five days after

they were caught, and seventeen days since any of them had

touched food, and about a month after most of them had fed, I

gave them five sardines, very flat fish, about eight inches long

and two inches broad. There were about thirty hags in the

tank, and by this time most all of them seemed to be hungry,

for they ate all but one of the sardines. This was the only

ume ravenous hunger was observed during the summer. The

No. 465] STUDIES OF MYXINOIDS. : 647

moment the first sardine was thrown into the water, the hagfish

near it woke up, and went to it; other fish were thrown in, and

in a minute or so the whole tank was alive. They ate raven-

ously, five or six crowding each other around one sardine.

Within a few moments, twenty-one and a half of the two dozen

sardines had been disposed of ; the rest they finished during the

night. As they seemed to be hungry, six sardines were given

them four days later. The first was placed in the water very

quietly and with as little jarring as possible ; I had already

noticed that an object could be placed quietly in the water with-

out their paying any attention to it. When this first sardine

was put in, however, several fish within six or eight inches of it

were instantly on the alert, showing that they smelt it. They

swam over to it, nosed around it, and ate a little. In a minute

or so several fish at a greater distance stirred and came over,

and they too nosed around the sardine. Other sardines were

then thrown in, but comparatively few of the fish ate, and these

only lightly. Although there were more than one hundred hag-

fish in the tank, only two and a half sardines were disposed of.

They were not fed again for two weeks and a half. Then

seven sardines were given them. They woke up instantly and

examined them, nosing around them as a dog does around a

bone. About a dozen gnawed the fish in various places, and by

the next morning three of the sardines were entirely eaten, but

the others were untouched.

Of course in making these observations it was impossible to

tell which fish fed at the different times, and how long any one

fish went without food. But the day after the two dozen sar-

dines were eaten, two fish were taken upstairs and placed in the

small aquarium there, where they were kept for a month. Dur-

ing this month a sardine was offered them twice, and left with

them for thirty-six hours, but was untouched on both occasions.

It is thus apparent that they can go à long time without food,

and do not eat nearly so heartily when they do feed as has

been supposed. The explanation of the greater hunger of those

freshly caught probably lies in the fact that they were rather

hungry when they found the food in the trap, and that some of

them had not been able to get enough of it to satisfy them.

648 THE AMERICAN NATURALIST. | [Vor. XXXIX.

The question of parasitism can, I think, be answered fully in

the negative. There is nothing in their structure to indicate

degeneracy, either of the feeding organs, or of the senses with

which they search for food. Moreover, they have no means of

attaching themselves to living prey, unless that prey is held help-

less on a line or in a net. They have neither hooks nor a suck-

ing disc with which to hang on, and the palatine tooth is too

short and placed too far back in the mouth to be used for this

purpose. They can only swim and bite, and I hardly think they

could make much headway with a powerful free-swimming cod

or halibut.

There is one food, however, of which the males are extremely

fond, and that is the eggs of their own kind. They eat these

in great abundance, swallowing them whole. One evening, just

before leaving the laboratory, I found a dead fish in the tank.

It was a female with eggs almost ready for oviposition, and on

lifting it the eggs were pressed out. I left them in the tank,

twenty of them all told, to see what would happen. The fish

had been fed the day before, and had eaten scantily, so they

were not hungry, but by morning all but one of the eggs had

been eaten; a day or so later I found the empty shells cast

out. The egg is swallowed whole, and its contents slowly

digested out of it by osmosis, leaving the shell untouched, or at

most with only a prick in it given in passing over the teeth. I

have examined several hundred eggs that had been pressed out

from the intestine, and were in all stages of digestion, from the

first murky clouding to the breaking and drawing off of the con-

tents. In none of them was the shell really broken. In many

of the largely digested ones there was no sign even of the pin-

hole prick, while in others quite undigested, the perforation of

the shell was very evident. It must therefore be purely acci-

dental and in no way necessary to digestion. :

SENSE PERCEPTION.

The hagfish has all of the usual sensory nerves and sensory

un barring the lateral line organs, possessed by the higher

shes, but they are all in a very primitive condition. It was

No. 465.] STUDIES OF MYXINOIDS. 649

interesting by experiment to see what use was made of them.

The eyes are not exposed on the surface, like those of other

fishes, but are covered by the skin, which is, however, trans-

lucent for an area of about a square centimeter over them.

There is nothing, therefore, to prevent the free passage of light.

It has already been stated that when in the tank they would lie

sometimes with their heads hidden in the rocks, but just as often

with them projecting out into the light. It was suggested to

me that this might be due to their wanting open water to

breathe, and that possibly, other things being equal, they would

prefer the dark. So to test it, two fish were placed in a large

pan, three feet long by a foot wide, and half of the pan was

covered making it very dark, while the other half was left open.

It was a gray day, which made the light in the open end of the

pan what they were accustomed to down in the tank. Both the

fish were sluggish and did not swim much, but they were dis-

turbed a number of times, and made to change positions. Each

time when they settled down they seemed regardless of the

light. They would settle quite as often at the light end of the

pan as at the dark end. To make a surer test, two lively young

fish were placed in a round dish about a foot in diameter and

covered with an inch of water.. After swimming rapidly for a

few minutes, they settled down into tight coils. The dish was

placed on the table in the photographic dark room, and a micro-

scope lamp was lighted. The lamp had a light-tight iron chim-

ney, with a curved glass rod coming out opposite the flame to

concentrate the light on the disc at its far end. This disc was

about a centimeter in diameter. The fish chosen were particu-

larly valuable for the experiment because they were young and

the skin over the eyes was unusually clear. In one of them it

was transparent, so that I could distinctly see the eye beneath

it. In the dark room the circle of light coming from the glass

disc was held an inch above the water. It could as well have

been at the other end of the room as far as observable results

were concerned, for they paid no attention to it. It was moved

closer and closer to them, finally being placed under the surface

of the water, and within an eighth of an inch of their skin,

without obtaining an observable reaction. At all of these differ-

650 . THE AMERICAN NATURALIST. [Vor. XXXIX.

ent distances, the light was moved so as to fall on different

parts of each fish's body, eyes, tentacles, head, back, sides, etc.,

and there was no reaction to it by either hagfish.

In regard to whether they could perceive objects or not, the

first thing that I noticed about them was, that when swimming

rapidly in crossing the tank from side to side, they would

repeatedly strike the tank head foremost; and when one was

taken from among the rocks and held for some minutes in the

hand or dropped in a corner of the tank, it would proceed very

cautiously, moving its head from side to side, keeping its tenta-

cles outstretched, and apparently depending on them for knowl-

edge of its surroundings.

The two young hagfish referred to above I also tested for

image perception, holding various objects close over their eyes,

and bringing them nearer and nearer. They showed no reac-

tion, no matter how near the object was, until the surface of the

body was touched, when they jerked their heads away. These

hagfish were neither sleepy nor sluggish, but were undoubtedly

normal. The conclusion drawn is, that the perception of vari-

ations of light and shade even when extreme, does not irritate

the eyes.

The evidence in regard to their hearing is just as negative as

that concerning their sight, I was not able to find any noise or

sound to which they would respond.

In testing the sense of touch, very different results were

obtained. If the tank is jarred, the fish immediately tighten

their coils ; if they are touched suddenly they jerk their heads

away. When they are swimming, and often when they are at

rest, the tentacle crown is extended, and the tentacles, moving

back and forth, sense the water currents or anything they may

strike against. When swimming in search of anything, the ten-

tacles are always on the alert, as tactile outposts or sentinels.

The same two fish that were studied for light perception,

were also experimented on for touch, and were touched lightly

m. different places with a straw, a glass rod, and a fine needle.

When touched lightly, fish A would not respond, but fish B

would jerk itself away. Touching any part of the skin, whether

of the head, over the €ye, on the back, on the side of the body,

No. 465.] STUDIES OF MYXINOIDS. 651

etc., gave the same reaction for each fish; A, as a rule, reacting

less energetically than B. But if the tentacle of either fish was

touched, the reaction was much greater, each fish jerking the

tentacle sharply aside. There seemed to be no difference in

sensitiveness between the base and tbe tip of the tentacles, and

the fish responded the most of all upon being touched in the

angle formed by the tentacle with the head. B jerked away

when touched directly over the nose, but A did not notice it,

and neither gave more attention to being touched over the eye-

ball than in any other part of the skin.

In most cases when they react to the touch stimulus, they

respond by curling the body tighter.

I placed a third young hagfish in the dish with the two, and

then tried placing various liquids on or near them by means of

a pipette. First as a control I used ordinary sea water.

When a stream of this was directed from a pipette against the

tentacles and rim of the nose, they would draw the head a little

to one side.

Ordinary alcohol was dropped in the water, one drop after

another in front of B, within a half inch of the tip of its nose.

Some of the drops touched it in mixing with the water, others

did not. The contact of alcohol did not produce observable

reaction until after twelve drops had fallen, when it moved away.

When fish C was treated the same way, eighteen drops fell

before it moved ; the nineteenth touched it and it moved its head

aside. B was touched again just as before, and again jerked its

head away after the twelfth drop. The thirteenth drop placed

in front of it at the usual distance, made it swim off toa dif-

ferent part of the dish. In this new position, eleven drops

were given it one by one. and it moved at the eleventh. C

treated a second time, took twenty drops before giving any

reaction. The twenty-second made it a little uneasy ; at twenty-

three it moved its head slightly, and at twenty-four swam away.

I followed it with another drop, and it went back to its old place.

Three minutes later, it took five drops that all touched it in

mixing. It quivered slightly at the third and fourth, but did

not move aside until the fifth.

One drop of hydrochloric acid placed in the water near the fish

652 THE AMERICAN NATURALIST. [Vor. XXXIX.

will make them jerk violently away if it touches them in any

place while mixing with the water. . A drop of strong ammonia

does the same. The ammonia throws down a precipitate of

ammonium chloride on the surface of the water, and if this

drifts against them before dissolving they show extreme irrita-

bility. Inallthese cases it is largely the sense of touch that is

affected, as the reaction was the same whether the mixing drop

touched the tip of the tentacle, the rim of the nose, or the side

of the head, and it was the touching of the mixture that pro-

duced the effect, except in the case of the alcohol, for it was

found that when the visible mixture of the drop of acid or am-

monia stopped even an eighth of an inch away from. the fish,

there was no reaction. With the ammonia this could be seen

still more plainly, for wherever the ammonia was dropped, it was

not until the ammonium chloride touched the skin, whether on

tentacle, tip of nose tube, or skin at the side of the head, that

the jerking away occurred. With the alcohol it was sometimes

a drop that touched that caused the effect, sometimes not.

With the many drops put in, only some of which touched the

hag, and those not affecting it, it may be that the sense of smell

was excited, or it may be that the alcohol finally irritated the

mucous membrane lining the nasal tube, or possibly the skin of

the tentacles. The foregoing experiments with the acid and

ammonia were begun at half-past three o'clock, and were contin-

ued until five. By that time the eels had become very languid

and were lying in the crescent shape. The next morning they

were all right again.

Notwithstanding the negative results of these experiments in

regard to the sense of smell, there is no question but that it is a

most serviceable sense for the hagfish. As they cannot see, it

is the means by which they know when they are near food. I

cannot tell at what distance they can detect an object by the

sense of smell. When the dead fish was placed in the tank, as

stated above, and the hagfish within six inches were aware of it

immediately, it took a perceptible time for those farther off to

become so, but the scent reached those as far off as eighteen

inches to two feet. How much farther it would go I do not

know. It probably varies with different individuals.

No. 465.) STUDIES OF MYXINOIDS. 653

I was hot able to gather any data as to the sense of taste. So

far as may be judged from observable reactions, the senses of

touch and smell are the most important in the life of the hag-

fish. Watching its life for four months and examining its

brain, both confirm this. Several times, to see what would hap-

pen, I took apart the rockery, transferring it to the other side of

the tank. The hagfish, suddenly deprived of their place, were

restless. First they moved their heads and the fore part of

their bodies, groping around, and then began to swim. They

swam in a slow, searching manner, sometimes feeling their way

along the side of the tank, and always with their heads moving

slowly from side to side, tentacles on the alert. Most of them,

when they touched the rocks with a tentacle tip, would recognize

them instantly, and go right in. Many on approaching within

an inch or an inch and a half of them, would plunge straight for

them, probably having smelt them. But there were others that,

while searching, would glide directly over the rocks, perhaps even

touching them with their bodies or the sides of their heads, or

even with their tentacles, yet would give no evidence that they

noted their presence ; instead, they would continue their search

farther afield, and eventually get back to them again.

On the other hand, they sometimes have a wonderful surety

of motion. One morning I found one hagfish that had made a

loop of its body, and was lying motionless, while three others

were swimming through the loop, one after the other. They

would dash through, describe a large circle from eighteen inches

to two feet in diameter, come back to the starting point, and

plunge through again. The hole in the loop was less than two

inches across, and in the few minutes that I watched them, not

one of the three hesitated, or failed to pass quickly and surely

through the loop.

But they do not always carry sense of direction so well. If 4

took one away from the rocks, and dropped it immediately NR

or eight inches off,it generally went straight back. But if I

held it a minute or so, or dropped it farther away, it would have

to search for its resting place. Sometimes it would search and

find it; sometimes, not finding it immediately, it would —

slowly around and settle down.

654 THE AMERICAN NATURALIST. [Vor. XXXIX.

In other ways there is a difference in sensitiveness in the hag-

fish, showing in the varying strength of the reaction caused by

different stimuli. The difference in the two fish with regard to

the alcohol was one of these. At one time when two healthy

fish were in the small aquarium, I struck the table on which the

latter stood with a heavy iron bar, thus giving the aquarium a

decided jar. The fish responded by tightening up their coils at

the tail end, and then loosening them again, one fish reacting

more strongly than the other. I pounded regularly at intervals .

of about five seconds, and they responded each time, the one

always in a slightly more marked degree than the other, but the

responses getting less and less, until at the twelfth blow they

were no longer given. Half an hour later, when they were

lying quietly, I tried again. This time they stopped at the eighth

pound. The next day they were apparently more irritable, for

they were still responding at the twentieth blow.

Their movements of defence are interesting. When caught,

their efforts of escape are purely of the reflex order, trying to

slip out of what is holding them. They wriggle and squirm to

get away, throwing out their heads and wrapping their tails

about one's wrist, but they rarely bite. The tooth plate is a

formidable weapon, but they seldom use it as such. Of all the

five hundred and fifty hagfish handled last summer, but few

snapped, and only one bit. This is in keeping with the experi-

ence of others who have handled them.

Their power of reflex action is very strong, and when the

head is cut off the body wriggles as violently without the head

as it could with it. It will wriggle of itself for several minutes

after the head is off, and after it becomes quiet it will respond,

if touched, for several hours after the beheading, two or three

hours in any case, and with the younger, smaller fish much

longer. A fish was stretched out and nailed to a board, and

injected through the heart with methylene blue. Forty-five

minutes later the head was cut off, and the body thrown into a

pan. Two hours after this a second headless body was thrown

upon it and the first squirmed and tied itself into a knot.

These reflexes are just as strong in the tail end of the body as

in the head end. Once in trying to open a hagfish to remove the

No. 465.] STUDIES OF MYXINOIDS. 655

ovary, the fish, although it had already been beheaded, squirmed

so that it was almost impossible to operate. The body was cut

in half in the hope of quieting it, by cutting through the spinal

cord, but both halves squirmed as vigorously as ever. i

The most remarkable case of all was that of a young hagfish

eleven and a half inches long. It was beheaded before noon.

At five in the afternoon its body was opened its entire length.

As soon as the instrument touched it, it squirmed vigorously,

tying itself into a knot. In ten minutes the examination was

over, it was thrown into the ocean, and my attendant at once

reported that on touching the water it swam away. It would

be interesting to know how long its swimming continued.

In contrast with the spinal cord, the life of the brain cells is

short, particularly those in the fore part of the brain. When

the fish were beheaded, the brains had to be removed and put

into the kiling fluid within an hour or they were valueless for

histological work.

REPRODUCTION.

The hagfish have only one reproductive organ, a peritoneal

fold hanging from the roof of the right half of the body cavity.

When the eggs or sperm are ripe, the organ fills the entire

right side of the body cavity, but after discharge, it is all

absorbed except for a small matrix at the caudal end. In this

stage the sex of the organ is distinguishable only by histological

examination. It appears as a small thickly gathered frill, the

outer edge of which holds a multitude of tiny spheres, the

undeveloped ova or sperm spheres respectively. As the hag-

fish has no external marks of sex, in this stage it requires a

microscope to distinguish between male and female animals.

As the process of ripening proceeds, the frill becomes thicker,

and extends cephalad, the spheres becoming more numerous

and the ova growing ovoid in shape. The frill may extend pos-

sibly one third of the way cephalad, before its edge becomes

thicker, or the sex apparent. I cannot state positively at what

length this occurs, but by the time it has grown halfway along

the cavity, the edge is at least double in thickness what it was

656 THE AMERICAN NATURALIST. | [Vor. XXXIX.

in the beginning, and the sex plainly marked, the eggs being

ovoid bodies, about two millimeters long and the sperm spheres

larger than before.

Only between twenty and thirty egg cells develop into mature

ova during one cycle, many of those starting development being

arrested when from two to six or eight millimeters long, and

the other spheres failing to develop. Whether this applies to

the sperm spheres could not then be ascertained. No new facts

were observed relative to the question of hermaphroditism.

This condition was not present in any of the relatively few fish

examined by me.

The hagfish oviposits at all seasons of the year, but probably a

great many more mature in the spring than at any other season ;

and I think that no individual deposits eggs more than once a

year, perhaps not so often as that. Of those studied by me be-

tween July 1 and October 30, about half were in the resting

stage where it was impossible to detect sex difference. Among

the others I did not find any fully ripe male; of the females

only two had reached maturity, and of these but one produced

ripe eggs, while the other died from some unknown cause before

the eggs were deposited. The eggs are easily felt through the

thin body wall in handling the fish, and I had from ten toa

dozen fish with very large eggs under observation for six weeks

or more, but the time was not sufficient to bring more than the

one fish to the point of ovipositing.

The supposition that the greater number of hagfish breed in

the spring is also supported by the relative numbers of eggs

found at different times of the year. Embryos can be found at

any time in various stages of development, but most of those

taken even in September are small. -

Of thirty-seven embryos gathered between September 8

and September r5, eleven were too small to be taken from the

shell, eleven more were less than 30 mm. long, six were between

30 and 40 mm., seven between 40 and 50 mm., one 54 mm., and

one 65 mm. This last was evidently within a short time of

hatching, as it swam freely when taken from the shell. During

this same week only four recently hatched hagfish were brought

in, and of these one was 60 mm., one was 80 mm., and one 83

No. 465.] STUDIES OF MYXINOIDS. 657

mm. The fourth had lost the fore part of its head so that I

could not tell its exact length. I was told by the fisherman that

eggs in which blood vessels could be seen were not very numer-

ous before September. Late in September I received several

very mature embryos and newly hatched young, and also some

eggs in which the embryo was not more than eight millimeters,

and was told by the fisherman that if I wished some young

about four or five inches long to send for them at Christmas

time as they were most easily obtained then.

The eggs are difficult to find. .They are almost never taken

in deep-water dredging, even in beds where the fish are very

numerous. The United States Fish Commission steamer Alba-

tross was out for three months in the spring of 1904, exploring

the bottom of the Bay of Monterey, and in all that time only

one egg was brought up by the dredge. On the other hand,

Mr. Frederick Woodworth told me that in dredging for mol-

luscs on a mud bottom at a depth of from twenty to twenty-

five fathoms, he had several times brought up hagfish eggs. He

says also in answer to a letter of inquiry on the subject: “I

find from the fishermen that they have taken strings of eggs in

from fifteen to eighteen fathoms with their mesh nets in muddy

bottoms ; with trawls they have taken them in as deep water as

thirty-five fathoms, always on muddy bottoms." The one set of

eggs that was laid in my aquarium was laid on the sand bottom,

though there were the rock heap and the bare wood for the fish

to choose between. Under these circumstances it is certainly

probable that the hagfish do not breed in their usual habitat, but

seek shallower water and a soft bottom to do so. The explana-

tion for this will be found in the food habits of the young.

In gathering the eggs, aside from dredging, advantage is taken

of the fact that they are eaten by the males. The fishermen

set traps or lines for the fish, and when they are aver, hold

them firmly by the head with one hand and “ strip” the body

with the other, thus forcing out any eggs OF newly hatched

young, for these are also eaten. Under these circumstances,

only a very small proportion of the eggs obtained are m

histological study, as most of them have been more or less

digested. Even if they are sufficiently uninjured to use for his-

658 THE AMERICAN NATURALIST. | [Vor. XXXIX.

tological purposes, the embryo is generally so much hurt that it

will not develop further but must be fixed at once.

Hagfish embryos are exceedingly slow in developing. The

evidence pieced together from the eggs brought in and the

statements made by the fishermen as to the seasons when cer-

tain sizes of embryos were most easily found, was confirmed by

the development of the seven eggs laid in the aquarium.

The average egg when laid is about twenty-three millimeters

long (though some are shorter by several millimeters), and about

six millimeters broad at the broadest place. The opercular ring

is three millimeters from the animal pole (Fig. 5, 2). Very rarely

a second ring is found at about the same distance from the vege-

tal pole.

Fic, 5.— i 1 :

IG. 5.— Eggs in the early stages of development. a, fresh laid egg; 4, the same egg with

mal pole; c, three-

_ Dean ('99) speaks of the egg being encased, when deposited,

in two outer membranes, both of which are shed shortly after

laying. Several eggs were brought me by the fisherman that

had evidently been secured before they were ripe for oviposition.

These eggs were identical with those, mentioned above, that I

No. 465.) STUDIES OF MYXINOIDS. 659

had obtained from a hagfish which died in the aquarium. They

were covered, anchor filaments and all, with a tough white mem-

brane, translucent, but not transparent. When this was stripped

off there was no second membrane inside, but instead, a thick

jelly-like substance that filled in all the space between the egg-

shell proper and the outer membrane. I do not hold with Dean

that this outer membrane and jelly is shed shortly after laying,

but think, instead, for two reasons, that the egg is freed from it

before being deposited. The set of eggs in this condition taken

from the dead fish, was left in the aquarium, and all but one

were eaten before morning. That one, however, was left un-

touched. It had its outer membrane still on it, and remained in

this condition. My second reason is, that the eggs normally

laid in the aquarium, seven of which had been undisturbed, were,

when I first saw them, entirely free from any such structure.

They were in two groups, a group of four and a group of three,

joined together by their anchor filaments and forming two

parallel straight lines. There were no cast off membranes any-

where to be seen, and whatever might have happened to the

jelly, the membrane could not have been dissolved by the salt

water. Moreover, the eggs were joined by the anchor filaments,

which could easily have happened if they were deposited free of

membrane and jelly, but would have been impossible otherwise,

as there was no force in the tank that could have changed the

position of the eggs after they were deposited, or could have

arranged them in regular groups. If the membranes were cast

off after extrusion, what became of them? If they dissolved

(and the one on the egg of the other set was neither dissolved

nor cast off) how were the eggs pushed close enough together

for their anchor filaments, previously separated by at least two

thicknesses of membrane, to interlock ? wi

I transferred the seven recently deposited eggs toa dish, in

Which was a constant flow of fresh salt water, in the hope that

some of them might prove to be fertilized. The fresh eggs were

a delicate, brilliant. yellow in color with a white mass at the anı-

mal pole. I found them Tuesday morning, September 20th.

Fig. 5, a, shows one in its normal state ; b isthe same egg

without the anchor filaments, and shows the protoplasmic mass.

660 THE AMERICAN NATURALIST. (VoL. XXXIX.

In the evening of the same day, two eggs, a and 4, showed this

protoplasmic mass extending halfway between the animal pole

and the opercular ring. On the next day æ had this mass

extending two thirds of the way to the ring, while 4 was appar-

ently unchanged. No changes had been noticed in any of the

other eggs. Thursday showed no particular change in any of

the eggs. On Saturday morning, the fourth day, a had a trans-

lucent cap, lighter in color than the rest of the egg, extending

from the animal pole to one millimeter past the ring (Fig. 5, 4),

while in ? the protoplasmic mass at the pole came two thirds of

the way toward the ring, and was grouped in three distinct ter-

races (Fig. 5, c). The other eggs had merely the protoplasmic

mass, coming halfway to the ring.

By three P. m. the same day, the cap of a had grown ı mm.

measuring 5 mm. from the pole to its edge at its deepest place.

Before noon the next day it had grown 2 mm. more, measuring

7 mm. all told. Egg ? had lost its terraces, and gained instead a

cap, coming to within 3 mm. of the ring, while a third egg, e,

which had heretofore appeared quiescent, showed a marked ter-

race. One hour later the cap on é had passed the ring by 3 mm.

At this time a is represented by Fig. 5, e; by Fig. 5, 4; and c

by Fig. 5, c. ;

Monday, the sixth day, at ten a. m., the cap on a was 9 mm.

deep, and on 4, 5 mm.; c was still in the terrace state, and ter-

races were showing faintly on d; a also had a tiny white dot, 1

to 1 mm. below the ring, and in the middle of the flattened part

of the egg. That same day at five P. m. the cap of a measured

IO mm. and the white speck was just the same, d’s cap was 6

mm. deep, the terraces of c and d were unchanged, and terraces

were beginning to show on e; f and g were as they had been in

the beginning. By measuring carefully morning and evening

for several days I found that the average rate of growth of the

cap after the terrace state was passed, was two millimeters in

twenty-four hours, and that the time of highest rapidity was

between ten A. M. and five P. M, as much space often being

planc then as was covered between five P. m. and ten the next

morning.

Tuesday, a and å were progressing at the usual rate of growth,

No. 465.] STUDIES OF MYXINOIDS. 661

c had a cap reaching a little more than a millimeter past the

ring, and /, in which I had not previously noticed any terraces,

had a cap a trifle deeper than thatof c. The caps in the earlier

stages are very hard to detect, as the difference in translucency

between them and the rest of the egg is very slight, and the

shell somewhat opaque.

Wednesday morning at the end of the first week, a’s cap was

13 mm. deep, /'s 9 mm, cs 7 mm., f’s 8 mm., while æ, which had

shown terraces almost as soon as c, lagged behind with a cap of

. only a little more than 41 mm.

By five P. M., a’s had grown 1 mm, 5 had not changed at all,

while on the others the caps had grown 2 mm. each, twice the

usual amount. That night, however, they all grew at the regu-

lar rate. Meantime, the white speck on a was no longer visible.

On Friday,the tenth day, in addition to the usual increase in

size of the cap, a very fine white line appeared on ca little be-

low the ring, whose further history could not be traced.

On Monday, October third, at five P. M., not quite fourteen

days after the eggs were laid, the blastopore of a was closed.

Within a few days the blastopores of the other developing eggs

closed also. Within this week, owing perhaps to very hot

weather, the eggs died.

But they had lived long enough to uiri the idea of their

exceedingly slow growth: fourteen days from the beginning of

development to the closure of the blastopore, and no head eleva-

tion, or primitive streak showing in this time. In all eggs

where the primitive streak shows, or where the young embryo

does not extend the full length of the egg, there is a cap over

the egg, that extends about one millimeter beyond the tail of the

embryo. This second cap, however, is caused by changes in the

yolk. With the appearance and growth of the mesoderm, the

yolk near the embryo and immediately beneath the shell be-

comes spongy and fullof vacuoles in which lymph and blood

spaces are laid out. This gives this part of the yolk a whiter

appearance than the rest and so forms a cap.

It is worthy of note that the five eggs that began to develop

were supposedly all fertilized at the same time; nevertheless,

there was a difference of from one to three days in the zes

662 THE’ AMERICAN NATURALIST. | [Vor. XXXIX.

of development, and only one started immediately. How shall

we account for the uneven rates of growth noticed in one or two

eggs afterwards, for instance on the day when 2 did not grow at

all, and the others grew twice their usual daytime amount ?

What caused f to lie apparently quiescent for several days, then

omit the terrace state, or cut it down to a ten or twelve hours

at most, instead of the thirty-six to forty-eight it generally lasts

and then growing with a leap, outstrip its brothers c and d, and

finally even 2? The eggs were all kept under identical condi-

tions, and the most marked variations were in those in the same

dish. It would seem impossible for external conditions to affect

one without affecting all the others, yet here were decided varia-

tions in a process generally much more uniform.

No. 465.] STUDIES OF MYXINOIDS. 663

BIBLIOGRAPHY.

AYERS, HOWARD.

'94. Bdellostoma dombeyi, Lac. Biol. Lectures at Woods Holl, in

Summer Session of 1903. Ginn & Co., Boston.

AYERS, HOWARD, AND JACKSON, C. M

:00. Morphology of the ie. Bull. of the University of Cin-

cinnati, October.

BEARD, J.

'92. Notes on Lampreys and Hags. Anat. Anz., vol. 8, pp. 59-60.

CUNNINGHAM, J. T.

he Reproduction of Myxine. Zool. Anz., no. 256, pp. 390-392.

CUNNINGHAM, J. T

':87a. On the PT and Development of the Reproductive Elements

in Myxine glutinosa. Quart. Jour. Micr. Sci., vol. 27, pp. 49-76.

CUNNINGHAM, J. T

':87b. The Reproductive Organs of Bdellostoma. Trans. Roy. Soc.

Edinburgh, vol. 33, pp. 247-250.

DEAN, BASHFORD, (with others).

'97. The Columbia University Zoölogical Expedition of 1896. Trans.

N. Y. Acad. Sci., vol. 16.

DEAN, BASHFORD.

'99. On the Embryology of Bdellostoma stouti. Festsch. zoten Geburts-

tage von Carl von Kupffer.

DEAN, BASHFORD .

:04. Notes on Japanese Myxinoides. Jour. College of Sci., Imperial

University, Tokyo, vol. 19, art. 2.

Howes, G. B.

’94. Biology in America. A Prospect. ature, vol. 51.

MÜLLER, JOHANNES. ;

’34. Vergleichende Anatomie der Myxinoiden, der Cyclostomen mit

durchbohrtem Gaumen. Abh. k. Akad. Wissensch. Berlin, 1834, pp.

65-340

PuTNAM, F. W.

’73. Notes on the Genus Myxine and Genus Bdellostoma. Proc. Bos-

ton Soc. Nat. Hist., vol. 16.

CINCINNATI, OHIO.

April, 1905

NOTES ON THE GENITALIA OF LYMNZEA.

FRANK COLLINS BAKER.

INTRODUCTION.

WrrH the exception of Lymnea megasoma and Lymnea

mighelst, nothing has been published on the genitalia of the

American species of Lymnza. Last fall the writer embraced

the opportunity to dissect most of the common eastern Lymnzeas,

with some interesting results which are presented in the follow-

ing paper.

In studying this subject it is eminently desirable that the

material should be freshly killed and not alcoholic, as the latter

condition causes portions of the

genitalia to contract and otherwise

lose their normal shape. Likewise

in observing the male organ it is,

essential that it should be fully in-

verted, otherwise the form of the

penis-sac and the length of the

penis will be much modified, as

shown by the accompanying cut

(Fig. 1). The genitalia of the nine

species examined are comparatively

uniform, differing principally in the

form of the prostate and in the

length of the penis. The vagina

and uterus also show some modifica-

tions.

The material dissected was ob-

tained from the following sources:

L. stagnalis appressa, stagnalis jug-

A B

Fic. ı.— Male organs of Lymnza. a,

penis partly everted in penis-sac ; 4,

fully inverted. Note the different mad

the penis-sac in the two conditions

ularis, elodes, and humilis were collected in Braddock's Bay,

Lake Ontario; Z. emarginata and catascopium were collected

665

666 THE AMERICAN NATURALIST. [Vor. XXXIX.

in Seneca Lake, N. Y.; L. desidiosa was obtained from Allen’s

Creek, N. Y.; Z reflera was obtained from Long Lake, near

Millers, Indiana, and Z. auricularia was secured in the green-

house in Lincoln Park, Chicago. All but the last two were

dissected in September.

In the figures the different parts of the genitalia are desig-

nated by the following letters: a/, albuminiparous gland; cm,

Fic. 2.— Lymnea stagnalis jugularis opened from above,

D showing the reproductive organs in

their natural position. . p ,

columella muscle; fx, nerves to female organs; g, gizzard; /,

liver ; m, mantle ; mn, nerves to male organs ; o, ovotestis ; ov,

oviduct ; os, Ovisperm or hemaphrodite duct ; 5, penis ; pa, duct

of prostate gland; Pr, prostate gland ; ps, penis-sac ; pmp, penis

protractor muscles ; Pmr, penis retractor muscle; fy, pylorus ;

rs, radula sac; s, spermatheca or receptaculum seminis; sd,

eca ; æ, uterus; o, vagina; vd, vas deferens.

The position of the genitalia is the same ın all of the species

No. 465.] GENITALIA OF LYMNEA. 667

examined, the male and female organs opening by separate

orifices, that of the former being behind the right tentacle and

that of the latter at the base of the neck, not far from the pul-

monary opening. The genitalia occupy the median portion of

the body cavity and are the most conspicuous organs when the

animal is opened from the back (Fig. 2). The female organs

closely embrace the alimentary tract, stomach, and esophagus,

the ovotestis being imbedded in the liver near the posterior part

of the animal. The male organs lie to the right of the buccal

sac, the vas deferens being coiled up between these two organs.

The relations of the different organs cannot be made out until

they are spread out and separated from each other.

Discussion OF SPECIES.

Lymnea stagnalis appressa Say. (Figs. 3, 4.)

Male Organs. — Penis-sac very large, cylindrical, rather wide

at the external opening and narrowing toward the distal end

where the penis is attached. The penis is very short and rather

thick, about one fourth the length of the penis-sac. There are

three sets of protractor muscles on the penis-sac and two sets of

retractor muscles. A large, thick muscle is inserted in the head

of the penis at one end and is attached to one of the retractor

muscles. The vas deferens is very long and extends from the

penis to the base of the penis-sac where it is lost in the columella

muscle, to appear again at the base of the vagina as the duct of

the prostate gland, which is long and hair-like and enters the

prostate in a rounded, bulbous-shaped organ, which gradually

narrows until it enters the ovisperm duct.

Female Organs. — The vagina is a narrow, cylindrical organ

about as long as the penis-sac. At the distal end it forms a

large, rounded, more or less pyriform uterus, which narrows to

form the oviduct, which is a tortuous, much folded organ, doubled

upon itself several times. This organ narrows and unites with

the ovisperm duct, which leads to the ovotestis or hermaphro-

dite gland, which is made up of rounded or lobulated follicles

and is strongly attached to the liver. The albuminiparous gland

668 THE AMERICAN NATURALIST.. (Vor. XXXIX.

is very large. The receptaculum seminis is rather small, pyri-

Fic. 3.— Genitalia of Zymnea palustris afpressa.

form, and is connected with the lower part of the vagina bya

long, narrow duct. Both male and female genitalia are supplied

Fic. 4.— Lymnea palustris appressa,

showing position of oviduct, prostate,

and ovisperm duct.

of the female organs,

with nerves, the former from the

cerebral ganglion and the latter

from the right visceral ganglion.

The organs are very brightly col-

ored, the albuminiparous gland, ovi-

duct, uterus, and receptaculum

seminis being orange, the prostate

orange shading into black at its in-

sertion, the vagina blackish white,

and the penis-sac flesh-colored. The

ovotestis is white, as are also the

muscles, vas deferens, and ducts

The ganglia are bright pink or orange.

No. 465.] GENITALIA OF LYMNÆA. > —— 669

The true relations of the hermaphrodite portions of the geni-

talia cannot be understood until the organs are separated and

spread out, when it is seen that the ovisperm duct divides into

two branches, one branch forming the prostate, which cares for

the spermatozoa, and the other branch forming the oviduct which

carries the ova. |

Lymnea stagnalis jugularıs Say.

The genitalia of this variety are in all respects like those of

variety appressa excepting in color, the prostate being brownish

yellow, the receptaculum seminis yellowish white, and the rest of

the female organs yellowish and flesh-colored.

Compared with the European sz/agnalis, the American varieties

seem to be almost identical. The figures in Keferstein (Taf.

103, Fig. 8) differ only in the form of the uterus, which is rep-

resented as more pyriform, and the bulbous part of the prostate

islarger. The penis is not clearly defined in the figure. The

figure in Prasch (Taf. 5, Fig. 7) is almost identical, the male

organs being shown in much detail The uterus is somewhat

differently shaped but this may be due to a different point of

view. There is nothing in the genitalia to separate the varieties

of stagnalis.

Lymnaa palustris Müller (= eledes Say). (Fig. 5.)

Male Organs. — The penis is almost as long as the penis-sac

and is very slender. The penis-sac is rather long, cylindrical,

and of large diameter. There are two large, wide, ribbon-like

retractors attached to the penis-sac and one muscle from the

head of the penis to the posterior retractor muscle. Protractor

muscles similar to those of stagnalis. Vas deferens long and

threadlike. Prostate duct very fine; prostate thick, cylindri-

cal, connected with the ovisperm duct as in stagnalis. |

Female Organs.— Vagina long, cylindrical, of narrow diameter,

enlarging to form a large, thick, pyriform uterus which narrows

to form the much folded oviduct, which in turn narrows to form

the ovisperm duct. Albuminiparous gland large. Receptacu-

670 THE AMERICAN NATURALIST. [Vor. XXXIX.

lum seminis very large and globular, its duct very fine, enlarging

somewhat at the point of insertion near the opening of the

vagina. Ovotestis and nerves as in stagnalis.

The colors of the organs are: albuminiparous gland and

uterus bright yellow, receptaculum seminis and prostate yellow-

Fic. um Genitalia of Lynn P MES TA ARS d

ish, penis-sac blackish, muscles,

whitish or flesh-colored.

Palustris differs from stagnalis in the greater length of the

penis, has a larger receptaculum seminis, a more pear-shaped

uterus, and the proximal end of the prostate is pyriform, not

bulbous,

penis, vas deferens, and nerves

No. 465.] GENITALIA OF LYMNAA. 671

Lymnea reflexa Say.

The genitalia of this species seem to agree in all essential

characteristics with those of palustris. The penis-sac has but

one retractor muscle while the penis has the long retractor

inserted in this muscle as in palustris.

Lymnea emarginata Say. (Figs. 6, 7.)

Male Organs.— Penis and penis-sac as in palustris and reflexa.

A single penis-sac retractor muscle in which the penis retractor

Fic. 6.— Genitalia of Lymnea emarginata.

is inserted. Prostate cylindrical, of large diameter, with a

somewhat bulbous proximal extremity, which narrows behind

and then enlarges, to contract again before connecting with the

ovisperm duct.

Female Organs.— The vagina is rather short and of large

672 THE AMERICAN NATURALIST. Vor. XXXIX.

diameter; the uterus is somewhat egg-shaped and very large ;

folded.

ored

uterus, a

oviduct large and much

Receptaculum

seminis globular, small,

its duct very fine, in-

serted near the opening

of the vagina.

miniparous gland large.

The organs are col-

ored as follows : oviduct

orange, male genitalia

blackish white, the rest

of the organs flesh-col-

Albu-

The genitalia of emar-

ginata differ from those

of palustris in having

a more bulbous-shaped

smaller re-

ceptaculum seminis and

a more cylindrical pros-

Fic. 7.— Genitalia of Lymncea emarginata, the organs sepa- tate, which terminates in

rated to show their relations to each other. Note the divi-

sion of the ovi d £ h 14 3

osta

largement

like those of palustris.

Lymnea desidiosa Say. (Fig. 8.)

Male Organs.— Similar to those of emarginata.

The prostate is whitish and is irregularly fusi-

form, tapering at both extremities. Muscles and

their insertions as in emarginata and reffexa.

Female Organs.— The vagina is very short and

the uterus is large and long and pyriform in

shape. The receptaculum seminis is globular in

form and large

emarginata.

a somewhat bulbous en-

resembling

that of stagnalis. The muscles of the penis and penis-sac are

r ın proportion than that of me & — foun

Lymnea desi-

No. 465.] GENITALIA OF LYMNEA. 673

Lymnea humilis Say.

The genitalia of this small species appear in all respects like

those of desidiosa. The receptaculum seminis is a rich salmon

color, the prostate is whitish, and the rest of the organs are

yellowish white.

Lymncea mighelsi Binney.! (Fig. 9.)

Male Organs. — Penis-sac cylindrical, very long and of large

diameter. Penis long and slender, half the length of the penis-

FıG.9— Genitalia of Zymnea mighelsi. The male organs are drawn somewhat nearer the

f 1 h F^ +

sac. There is a single stout, ribbon-like retractor muscle attached

1 The description of mighelsi is modified and corrected from that eed in

Bull. .Chicago Acad. Sci., vol. 2, no. 5, p. 202.

674 THE AMERICAN NATURALIST. [Vor. XXXIX.

to the distal end of the penis-sac; and the penis muscle, which

is attached to the head of the penis, is inserted in this muscle

near its attachment to the columella muscle. Vas deferens and

innervation as in the other species described. The prostate is

large and cylindrical at its junction with the prostate duct, but

becomes very long and narrow at its posterior portion and again

narrows as it unites with the ovisperm duct.

Female Organs.— The ovotestis is made up of the usual lobu-

lated follicles. The ovisperm duct is rather long; the oviduct

is a much lobed organ, rather long and of large diameter ; it

enlarges to form a long, cylindrical uterus which suddenly con-

tracts to form the vagina. The receptaculum seminis is small,

elongate-ovate in form and connects with the vagina rather high

up by a narrow duct. The albuminiparous gland is not large

and is of the usual form. The innervation is as in the other

species described.

The organs are colored as follows: penis and penis-sac yel-

lowish, prostate yellowish or amber-colored, ovotestis yellowish,

albuminiparous gland greenish, receptaculum seminis pearly

white, and the other organs yellowish. The muscles are white

in color. |

The genitalia of mighelsi differ from those of all the other

species described in the form of the uterus, which is long and

cylindrical while the vagina is short and wide. The prostate is

also differently shaped. The penis-sac is very long and wide

while the penis is about half its length. It is evident from a

study of the genitalia of mighelsi and emarginata that the for-

mer is specifically distinct from the latter. The penis is

shorter, the oviduct is differently shaped, as well as the pros-

tate. The shells also exhibit differential characters.

Lymnea catascopium Say.

Male Organs — In all respects like those of emarginata. The

Prostate is also like that of emarginata. The receptaculum

N I5 more pear-shaped. The uterus is not so swollen, the

distinction between -vagina and uterus not being very marked,

and the two organs form a long, somewhat cylindrical sac.

No. 465.] GENITALIA OF LYMNEA. 675

Lymnea auricularia Linné. (Fig. 10.)

Male Organs. — Penis-sac cylindrical, long, of large diameter.

Penis very long and slender, exceeding the penis-sac in length.

Penis retractor single, attached to the distal end of the penis-

sac by a double connection. Prostate in the form of an elon-

gated, inverted pear, narrowed at either end where it joins the

Fic. 10.— Genitalia of Z ‘cule

ovisperm duct and prostate duct. The prostate is dark gray in

color with the exception of a narrow band of white on the

Border, ^

Female Organs. — The ovotestis is of the usual form. The

ovisperm duct is of medium length. The oviduct is a much

676 THE AMERICAN NATURALIST. (Vor. XXXIX.

lobed organ, rather long and wide; it abruptly enlarges to form

a bulbous uterus, which narrows to form a rather long, wide

vagina. The receptaculum seminis is small and spherical and

connects with the vagina near its opening by a very long, nar-

row duct. The albuminiparous gland is very large. Nerves as

in the other species. The uterus is yellowish, the albuminipar-

ous gland is yellowish brown, the vagina is blackish white, the

receptaculum is bright red and the other organs are flesh-col-

ored.

The genitalia of auricularia do not resemble those of any

other species very closely. The penis is longer than in any

other species and the receptaculum is smaller. The uterus is

more swollen and of a different shape. The prostate resembles

that of both e/odes and mighelsi.

Moquin-Tandon's figure in the Histoire Naturelle des Mol.

lusques Terrestres et. Fluviatiles de France shows the organs of

different shape and position, but this may be due to viewing

them in a different position and without separating the organs.

Lymna@a megasoma Say.

? No specimens of this Species have been obtainable for dissec-

tion. Wetherby's description and figure in /our. Cincinnati

Soc. Nat. Hist., vol. 2, P. 95, show the penis to be rather wide

and shorter than the penis-sac. The receptaculum seminis is

ovate-pyriform. The other organs are not very clearly shown.

COMPARISONS.

The question has presented itself to the writer as to whether

the genitalia of Lymnza will afford sufficiently stable data upon

which to base Systematic groups or subgenera. In the land

shells these organs furnish, in many cases, excellent characters

for generic and even family divisions. It is possible that the

examination of a large number of species might produce tangible

No. 465.] GENITALIA OF LYMNEA. 677

results, but the data presented

in this paper seem hardly suffi-

cient for this purpose, although

some interesting features are

brought out.

In the foregoing remarks, nine

species and two varieties have

been discussed. In comparing the

genitalia of these eleven forms, sev-

eral notable facts are at once appar-

ent. The length of the penis as

compared with the penis-sac is ^ Ef MH

Eben { Fic. 11.— Comparison of the length of

st riking . The following table the penis with the penis-sac. a, stag-

$ . alis; 6, mighelsi, c, lustris ;

shows these relations (see Fig. rg Re

II):—

Comparative Length of Penis and Pents-sac.

One fourth length. One half length. Three fourths length. ^ Longer.

appressa mighelst emarginata auricularia

Jugularis palustris

reflexa

catascopium

desidiosa

humilis

megasoma ?

There seems to be some difference in the number of penis

retractor muscles attached to the penis-sac. In stagnalis and

palustris there are two, with a muscle extending from these

muscles to the penis. In emarginata, mighelsi, auricularia,

reflexa, desidiosa, humilis, and catascopium there is but one

retractor, in which is inserted the penis muscle. In auricularia

there is but one penis-sac retractor and no muscle is attached to

the penis. The prostate shows some differences, being fusiform

in some species (viz., desidiosa, auricularia, mighelst, etc.) and

cylindrical with an enlarged bulbous termination im the other

i 7 : ! ries

species (viz., stagnalis, emarginata). The uterus also va

from ovate to pyriform.

678 THE AMERICAN NATURALIST. | |Vor. XXXIX.

The colors of some of the organs, especially of the recep-

taculum, are striking. This latter organ is colored as follows

in the different species : —

appressa, orange. desidiosa, salmon.

Jugularis, yellowish. mighelsi, pearly white.

reflexa, yellowish. humilis, salmon.

emarginata, flesh-colored. auricularia, bright red.

The receptaculum seminis varies in several of the species,

both in size and in shape. In palustris it is of extraordinary size

while in auricularia it is very small.

While the characters of the genitalia do not seem to aid

materially in the establishment of higher groups they do aid

very largely in the separation of the species. The writer hopes

to be able to examine all of the American species in the near

future.

BIBLIOGRAPHY.1

BAKER, FRANK C.

The Gross Anatomy of Zimnea emarginata Say, var. mighelsi

Binney. Bull. Chicago Acad. Sci., vol. 2, pp. 191-211.

BAUDELOT.

à Recherches sur l'appareil générateur des mollusques Gastéropode s.

nn. des Sci. Nat., Zool., ser. 4, vol. 19, pp. 135-222, 268-294.

KEFERSTEIN, WILHELM.

'62-— Bronn's Klassen und Ordnungen der Weichthiere; Malacozoa.

- Leipzig und Heidelberg. :

LACAZE-DUTHIERS, HENRI.

'72. Du systeme nerveux des mollusques et d'un nouvel organe d’inner-

vation. Arch. Zool. Exp., ser. 1, vol. 1, pp. 437-500.

Moquin-Tanpon, A. ; : JR an

^ Histoire naturelle des mollusques terrestres et fluviatiles de France.

Paris, 2 volumes and atlas.

MoQurN-TANDON, A,

E. Observations sur les prostates des Gasteropodes androgynes.

Jour. de Conch., vol. 9, pp. I-19 :

1 1 2 . *

The list of works on this subject is not exhaustive.

No. 465.] GENITALIA OF LYMNEA. 679

PRASCH, A.

'43. Neben das Geschlechtssystem und die Harn bereitenden Organe

einiger Zwitterschnecken. Arch. für Naturges., 1843, pt. 1, pp.

71—104.

WAGNER, RUDOLPH.

'85. Bemerkungen über die Geschlechtstheile der Schnecken. Arch.

für Naturges., vol. 1, p. 368.

WETHERBY, A. G.

"79. Notes on some New or Little Known North American Limnzide.

Jour. Cincinnati Soc. Nat. Hist., vol. 2, p. 95.

WHITFIELD, R. P.

81. Description of Limnea (Bulimnea) megasoma Say, with an

Account of Changes produced in the Offspring by Unfavorable

Conditions of Life. Bull. Amer. Mus. Nat. Hist, vol. 1, pp.

29-37.

CHICAGO ACADEMY OF SCIENCES.

NOTES AND LITERATURE.

BOTANY.

Porter’s Catalogue of the Bryophyta and Pteridophyta of

Pennsylvania ! is an attractive volume of 66 pages. It is a list in

which localities and collectors are indicated after the name of each

species, and includes about 542 species and varieties. The cata-

logue was compiled by Dr. Porter, the mosses revised by Mrs. Brit-

ton, and the whole edited by Dr. Small. The names of such well

known collectors as James, Austin, Muhlenberg, Porter, Rau, Garber,

Burnett, Small, and Mrs. Britton appear many times throughout the

catalogue and add much to its value. The arrangement of families

and genera conforms very closely with that in Limpricht’s Die Zaub-

moose, Some exceptions to this statement will be noticed, e. g.,

Hylocomium is placed between Brachythecium and Eurhynchium.

Some of the most conspicuous changes in familiar generic names

are the following: Mollia Schrank for Gymnostomum (partly),

Gymnostomum Hedw. for Pottia, Weissia Ehrh. for Ulota, Leersia

Hedw. for Encalypta, Astrophyllum Neck. for Mnium, Arrhenop-

terum Hedw. for Aulacomnium (partly), Mnium Dill. for Aulacom-

nium (partly), Webera Ehrh. for Diphyscium, Eleutera Beauv. for

Neckera, and Forsstromia Lindb. for Leptodon.

The catalogue is well bound in a very neat cloth cover and is

clearly printed on good paper with a dead surface. It is absolutely

indispensable to all students of the Pennsylvania Archegoniates and

even the more general student should not neglect placing it in his

library.

LEC

Notes.— The seventh fascicle of the Genera Siphonogamarum of

' Dalla Torre and Harms, following the Engler sequence of families,

has reached Liabum, of the Compositæ — which bears the serial

number 9371.

Vol. 8, part 5, section 2, of the Reports of the Princeton University

Expeditions, to Patagonia, by Macloskie, deals with the phanerogamic

families Santalacez to Cactacex, and bears date of January 2.

1 Porter, T. C. Catalogue of the Bryophyta and Pteridophyta of Pennsylvania.

Boston, Ginn & Co., 1904. 8vo., 66 pp. $1.00

681

682 THE AMERICAN NATURALIST. [Vov. XXXIX.

The new edition of the Prodromus Flore Batave, in course of

publication by the Nederlandsche Botanische Vereeniging, reaches

the end of Apetalz in the third part of volume 1, recently issued.

A second part of de Wildeman's studies of Congo plants has been

issued from Brussels.

Vol. 5, part r, of Wood's Natal Plants, dealing with grasses, is

dated December, 1904.

“The Luquillo Forest Reserve, Porto Rico," is the title of Bul

letin no. 54 of the Bureau of Forestry, U. S. Department of Agricul-

ture, by Gifford.

A paper by Shimek on the flora of the St. Peter sandstone in

Winneshiek County, Iowa, is published in vol. 5, no. 4, of the Bul-

letin from the laboratories of natural history of the State University

of Iowa.

A colored plate of Shortia galecifolia appears in Flora and Sylva

for January.

A colored plate of Yucca guatemalensis is published in Curzis’s

Botanical Magazine of F ebruary. .

An account of Musa textilis, by. Edwards, forms Farmers’ Bulletin

No. 12 of the Philippine Bureau of Agriculture. |

A paper on the grasses of Walter's * Flora Caroliniana," by Hitch-

cock, has been separately printed from the Sixteenth Report of the

Missouri Botanical Garden.

Dulichium spathoceum is said by Hartz, in Engler's Botanische

Jahrbücher of February 28, to occur in Danish interglacial bogs.

An account of Welwitschia mirabilis, with original photographic

illustrations taken in its native home, is published by Baum in Die

Gartenwelt of March 18. ! Au.

Professor Greene publishes a number of new species of Aragallus

in the Proceedings of the Biological Society of Washington of January

20.

‚An account of the British Hieracia, recently published by W. R.

Linton, includes 124 species with numerous minor forms.

Habit and bark photograms of Fraxinus pennsylvanica are pub-

lished by Rothrock in Forest Leaves for February.

The 2oth Heft of Engler's “Das Pflanzenreich” consists of a

treatment of Zingiberacez, by Schumann.

No. 465.] NOTES AND LITERATURE. 683

No. 20 of the Bulletin de U’ Institut Botanique de Buitenzorg con-

sists of a paper on Javan Zingiberacex, by Valeton.

An epitome of the British Indian species of Impatiens, by Sir

Joseph Hooker, is begun in vol. 4, no. 1, of the Records of the Botani-

cal Survey of India.

Spegazzini records 140 cacti, of which many are described as

new, from the Argentine Republic in a paper separately issued from

vol. 11 of the Anales del Museo Nacional de Buenos Aires under the

title * Cactacearum Platensium Tentamen.”

A paper on Cephalotus by Hamilton, with other interesting botan-

ical matter, is contained in vol. 29 of the Proceedings of the Linnean

Society of New South Wales.

Some West American red cherries are described by Greene in the

Proceedings of the Biological Society of Washington of February 21.

A paper on the comparative anatomy and phylogeny of Abietinez,

by Jeffrey, forms vol. 6, no. 1, of the Memoirs of the Boston Society of

Natural History.

Dr. Moore’s Philadelphia address on “Applied Botany and its

Dependence upon Scientific Research” is separately issued from

Science of March 3.

Dr. Galloway’s recent report as chief of the Bureau of Plant Indus-

try shows in a concise way the varied investigations being carried on

by this branch of the national Department of Agriculture. Sixty-

one percent of the 490 employees of the Bureau are said to be

engaged in scientific and related work.

A popular account of henequen farming in Yucatan is to be found

in Modern Mexico of February.

A colored plate of the rose “Madame Norbert Levavasseur,”

which has been rechristened “Baby Rambler” in this country, is

published in Gartenflora of January ı.

A monograph of American varieties of lettuce, by W. W. Tracy,

Jr., forms Bulletin no. 69 of the Bureau of Plant Industry of the

U. S. Department of Agriculture.

An instructive winter tree-study bulletin, for young people, is con-

tained in the February-March number of the Cornell Home Nature-

Study Course.

684 THE AMERICAN NATURALIST. [Vor. XXXIX.

Some old British tree trunks are figured in vol. 22, part 3, of the

Transactions and Proceedings of the Botanical Society of Edinburgh.

The deformations of woody plants sometimes called “ witches’

brooms” are discussed by Solereder in the Nazurwissenschaftliche

Zeitschrift für Land- und Forstwirtschaft for January.

An account of graft-hybridization or symbiosis in Vitis is given by

Voss in Zandwirtschaftliche Jahrbücher, vol. 33, part 6.

The effect of self-pollination in Papilionacez is discussed by

Kirchner in the January Naturwissenschaftliche Zeitschrift für Land-

und Forstwirtschaft.

Seaside ecology in Ceylon finds exposition by Tansley and Fritsch

in Zhe New Phytologist of January 30.

An account of the Mandragora of the ancients in folk-lore and

medicine, by Randolph, forms vol. 40, no. 12, of the Proceedings of

the American Academy of Arts and Sciences.

The chemistry of indigo is considered by Hazenwinkel and Wil-

brink, in no. 73 of the Mededeelingen uit’s Lands Plantentuin, from

the Buitenzorg Garden.

A popular account of the seedless, coreless, and blossomless apples

is given by Thomas in 7%e American Inventor of April 1.

An interesting series of weed studies, by Waldron, constitutes Bue-

tin no. 62 of the North Dakota Experiment Station.

Von Schrenk reports on experiments in the chemical treatment of

railroad ties as a means of checking fungus growth, in Bulletin no.

51 of the Bureau of Forestry, U. S. Department of Agriculture.

Professor Macbride's Philadelphia address, on The Alamogordo

Desert, is distributed in separate form.

| That the raphides of Agave, like those of Sci//a maritima, Nar-

cissus, etc., may cause severe irritation of the skin is noted in the

Gardeners’ Chronicle of March 11.

Roth’s “ Die Europäischen Laubmoose" has reached a conclusion

in the recently issued rith Lieferung.

: An important contribution to the bryology of the Azores is pub-

lished by Cardot in the Buletin de l Herbier Boissier of February 28.

The supposed influence of fungi in Causing the formation of tubers

in Solanum has been further tested, with inconclusive results, by

No. 465.] NOTES AND LITERATURE. 685

Jumelle, whose paper appears in the Revue Generale de Botanique of

February r5.

Fusicladium pirinum, and its effect on the pear, form the subject

of Bulletin no. 163 of the Agricultural Experiment Station of Califor-

nia, by Smith.

Baodromus, a coleosporioid rust of Senecio, is described by Ar-

thur in Annales Mycologiei of February, which also contains other

papers on American fungi.

The Discomycetes of Iowa form the subject of a paper by Seaver

in vol. 5, no. 4, of the Bulletin from the laboratories of natural his-

tory of the State University of Iowa.

An analysis of the species of Phragmidium, by Dietel, has been

published in recent numbers of Hedwigia.

Atkinson's 1893 account of “Carnation Diseases " is reprinted in

The American Florist of January.

A discussion of soil bacteria and nitrogen assimilation, by Ches-

ter, forms Bulletin no. 66 of the Delaware College Agricultural Ex-

periment Station.

A paper by Moore on soil inoculation for legumes, with reports

upon the successful use of artificial cultures by practical farmers,

constitutes Bulletin no. 7r of the Bureau of Plant Industry of the

U. S. Department of Agriculture.

A further discussion of copper as an algicide and disinfectant in

water supplies is given by Moore and Kellerman in Buletin no. 76

of the Bureau of Plant Industry, U. S. Department of Agriculture.

A catalogue of the shrubs in the Vilmorin Garden, by Maurice L.

de Vilmorin and D. Bois, with descriptions of new or recently intro-

duced species, has recently been issued from the Librairie Agricole

of Paris.

An illustrated account of the desert laboratory at Tucson is given

by Lloyd in the Popular Science Monthly for February.

A Herkomer portrait of Sir Joseph Hooker is reproduced in half-

tone in Zhe Gardeners’ Chronicle of January 7.

A note on the work of Philippi, with portrait, is published by

Hicken in the Anales de da Sociedad Cientifica Argentina of October

last.

686 THE AMERICAN NATURALIST. | [Vor. XXXIX.

A portrait of B. L. Robinson is published in the Popular Science

Monthly for February.

The Journals. — With January, a new journal, Ze Nature Study

Review, appears under the editorship of Professor M. A. Bigelow

with a strong advisory board. It contains much of interest to the

teaching botanist.

The Iowa Naturalist is a new venture launched by T. J. Fitzpatrick

from Iowa City.

An attractive new periodical, Zhe Garden Magazine, is begun by

Doubleday, Page & Co., the first number issued being for February.

Botanical Gazette, January: — True and Oglevee, * Effect of the

Presence of Insoluble Substances on the Toxic Action of Poisons” ;

Livingston, * Relation of Soils to Natural Vegetation in Roscommon

and Crawford Counties, .Mich."; Elmer, “New and Noteworthy

Western Plants”; Olive, “ Morphology of Monascus purpureus" ;

Davis, * Fertilization in the Saprolegniales," and * The Sexual Organs

and Sporophyte Generation of the Rhodophycez.”

Botanical Gazette, February: — Barnes, “ The Theory of Respira-

tion”; Whitford, “The Forests of the Flathead Valley, Montana —

I”; Holm, “Studies in the Graminez: — VIII, Munroa squarrosa? ;

Chamberlain, * Alternation of Generations in Animals from a Botani-

cal Standpoint ” ; Ganong, *New Precision-Appliances for Use in,

Plant Physiology — II."

Botanical Gazette, March : — Coulter and Land, * Gametophytes

and Embryo of Torreya taxifolia” ; Olsson-Seffer, “The Principles

of Phytogeographic Nomenclature ” ; Whitford, “ The Forests of the

Flathead Valley, Montana — II ”; Arthur, “Terminology of the .

Spore Structures in the Uredinales.” |

nx no. 6. — Heller, * Western Species, New and Old —

ology”; Fink, “How to Collect and Study Lichens”; Holzinger,

” *

s * [11 . , * ri

gus"; Crockett, “ Rhacomitrinm heterostichum gracilescens?

: Buien of the Torrey. Botanical Club, December : — Emerson,

Notes on the Blackening of Baptisia tinctoria ” ; Rydberg, “ Studies

No. 465.] NOTES AND LITERATURE. 687

on the Rocky Mountain Flora — XIII"; Maxon, “ A New Asplenium

from Mexico.’

Bulletin of the Torrey Botanical Club, January : — Livingston,

“Chemical Stimulation of a Green Alga”: Arthur, “ Amphispores of

the Grass and Sedge Rusts”; Berry, “ Additions to the Fossil Flora

from Cliffwood, N. J.”

Bulletin of the Torrey Botanical Club, February: — Spalding, E.

S., “Mechanical Adjustment of the Suaharo (Cereus giganteus) to

Varying Quantities of Stored Water”; Horne, “A New Species of

Lembosia " ; Maxon, “On the Names of three Jamaican Species of

Polypodium”; Peck, “New Species of Fungi”; Murrill, “The

Polyporacez of North America — X”; Harper, “ Further Observa-

tions on Taxodium.”

The Fern Bulletin, January:— Harper, “The Fern Flora of

Georgia”; Davenport, “A New Type of Aneimia”; Hill, * Æguise-

tum scirpotdes in Illinois”; Van Hook, “Illinois Ferns near Lake

Michigan.”

Journal of Mycology, January: — Morgan, “ Spheria calva”;

Seaver, “ A New Species of Spharosoma”; Arthur, “ Sydow's Mono-

graphia Uredinarum, with Notes upon American Species”; Mem-

minger, “ Agaricus amygdalinus” ; Kellerman and Ricker, “New

Genera of Fungi published since the year 19oo [My. to X., with

index] "; Kellerman, * Uredineous Infection Experiments in 1904 ” ;

Kellerman, “ Elementary Mycology (continued) ”; Kellerman, “Ohio

Fungi, Fascicle X. List of Species and Hosts.”

Journal of the New York Botanical Garden, January :— Nash,

* Botanical Exploration of the Inagua Islands, Bahamas.”

Journal of the New York Botanical Garden, February : — Mac-

Dougal, “ Studies in Organic Evolution.”

Journal of the New York Botanical Garden, March: — Hollick,

“A Recent Discovery of Amber on Staten Island”; Nash, “The

Flowering of Nolina texana.”

The Ohio Naturalist, January : — Schaffner, “The Life Cycle of

a Heterosporous Pteridophyte "; Gleason, “Notes from the Ohio

State Herbarium — II”; Schaffner, “Mat Plants”; Schaffner,

“Plants with Nodding Tips"; Riddle, “ Brush Lake Alga”; Scholl,

“Key to the Ohio Hickories in the Winter Condition"; Cotton,

“Key to Ohio Ashes in the Winter Condition ” ; Schaffner, * Key to

Ohio Poplars in the Winter Condition.”

688 THE AMERICAN NATURALIST. . (Vor. XXXIX.

The Ohio Naturalist, February : — Schaffner, “Key to the Genera

of Ohio Woody Plants in the Winter Condition”; York, “The

Hibernacula of Ohio Water Plants”; Schaffner, M., “Key to the

Ohio Sumacs in the Winter Condition."

The Ohio Naturalist, March :— Wacker, “ Ecological Notes on

Obio Pteridophytes”; Flory, “Key to the Ohio Maples in the

Winter Condition ”; Schaffner, “ The Classification of Plants — I”;

Schaffner, “ Lycopodium porophilum in Obio”; Schaffner, “ The

Struggle for Life on a certain Sandbar”; Riddle, “Notes on the

Morphology of Philotria”; Tillman, “Ohio Plants with Tendrils ";

Schaffner, * Key to Ohio Walnuts Based on Twig Characters."

The Plant World, December : — Safford, * Extracts from the Note-

book of a Naturalist on the Island of Guam — XXV "; Blanchard,

“ Millspaugh's Blackberry.”

The Plant World, January:— Bayley Balfour, “ Physiological

Drought in. Relation to Gardening"; Brackett, *A Summer in the

Tropics” ; Watterson, * An Unusual Begonia”; Mansfield, “ A Curi-

ous White Oak.” — —

The Plant World, February : — Underwood, * A Glimpse at Early

Botanical Literature”; Brackett, “A Summer in the Tropies (con-

clusion)”; Pammel, “Notes on some Plants of Northeastern Iowa n

Schneck, “ Fasciation in the Cherry”; G[ager], “ The Protection of

Winter Buds.”

Torreya, January:— MacDougal, “ Discontinuous Variation and

the Origin of Species”; Nash, “A Paspalum New to the West

Indies”; Vail, * Onagra grandiflora, a Species to be included in the

North American Flora"; Britton, * Carex Underwoodii, sp. nov." ;

Clendennin, “ Twin Pine Embryos.”

Torreya, February : — Shull, * Galtonian Regression in the * Pure

Line’”; Spalding, V. M., “Soil Water in Relation to Transpiration ” ;

Murrill, “A Key to the Stipitate Polyporacez of Temperate North

America —I” ; Berry, “ A Palm from the Mid-Cretaceous " ; Britton,

& ry f EE 2. > ;

Galactia Curtissit sp. nov.” ; Sumstine, * Paneolus acidus sp. nov."

Torreya, March : — Underwood, “The Early Writers on Ferns

and their Collections — IV”; Clendenin, “Other Freaks of Peas” ;

Murrill, “A Key to the Stipitate Polyporacez of Temperate North

2 Ma m. 1 [11 BS r vs

Ameria H ; Britton, Jacquinia Curtissii sp. nov." ; Cockerell,

New Binomials in an Index."

No. 465.] NOTES AND LITERATURE. 689

Rhodora, January : — Brainerd, “Notes on New England Violets

-— II”; Fernald, “A Peculiar Variety of Drosera rotundifolia” ;

Dewey, “Identity of Prickly Lettuce” ; Fernald, “ Zedum palustre var.

dilatatum on Mt. Katahdin”; Parlin, “Further Notes on Arabis

levigata and Asplenium Trichomanes in Maine”; Leavitt, “On

Translocation of Characters in Plants”; Bartlett, “ Arenaria macro-

phylla in Connecticut”; Robinson, “A Connecticut Station for

Lycopodium Selago.”

Rhodora, February : — Leavitt, “On Translocation of Characters

in Plants (continued) ”; Fernald, “A New Arabis from Rimouski

County, Quebec”; Churchill, “Preliminary Lists of New England

Plants — XVII”; Clark, “White Form of Sabbatia chloroides” ;

Beattie, * Remarks on Rhode Island Plants."

Rhodora, March : — Ganong, “On Balls of Vegetable Matter from

Sandy Shores”; Fernald, * An Undescribed Northern Comandra ” ;

Hall, “ Vegetative Reproduction of Spiranthes cernua ?; Bartlett,

“A New Juncus of the Group Poiophylli” ; Evans, “ Notes on New

England Hepatica — III”; and Robinson, “A well marked Species

of Sparganium.”

(No. 464 was issued August 19, 1905.)

BERGEN'S

ELEMENTS OF BOTANY

REFISED EDITION

By . BERGEN,

Recently Instructor in teren, in the English High School, Boston

rn an? Central States. 12mo. Cloth. 283 + 257

Including Ey and Flora for

Without Key and Flora.

Illustrated. List price, prr M ; palling price, $1.45.

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ERGEN'S “ Elements of Botany,” Revised Edition, is Aie i ed to

ibi asco a half- en course in the subject for students

all t

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the what abbreviated kai iis for bilo logical work on s

th in die greatly eo. ity of the illustrations. Minor changes

will be found on almost e ui e .

THE BOOK IS CHARACTERIZED

By the natural €— of presentation, poems the pupil first, as Professor Huxley

recommen to th

By the más qos: use of technical — employing these only when they are indispensable

By bd treatment of the anaes ped ‘the functions of plants consecutively, not in

widely separated portions of the book.

Dy the i intimate « Tomna du a: a work with on taking pains, however,

not to ti p n words or Ly means of illustrations, what he is to sce

before he sees it for hin ici

Dy the accuracy of the Tranpa in arg a er rege being used only £o give gen-

eral effects, never for minute o

l iut. fave u eag ot epared to accompany the text.

By the fact that cie. special keys an

This v student i in any part of the = coun y to obtain er in the determ mi-

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nation 1

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Laboratories or for D: ndary Schools. Square 4to. Cloth. 144 pages. List price,

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DEVOTED TO THE NATURAL SCIENCES

IN THEIR WIDEST SENSE

CONTENTS

I A Peculiar Variation of Terebratalia rangyores Sowerby. DR. H. W. SHIMER 691

II. Studies on the Plant Cell.—VIII . . . . PROFESSOR B. M. DAVIS es

III. Diadasia Patton; a Genus of Bees . — ME 741

IY. Notes and Literature: General Biology, a Naturbegriffe und Natur- 79

teile, DeVries’ Species and Varieties; Zod/ogy, Sedgwick’s fere. 751

of Zoölogy, Aldrich's Catalogue ii North American Diptera, Barron's

Old Whaling Days, Notes; Anthropology, La sociologie génétique, 758

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The American Naturalist.

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ersit

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J. G. NEEDHAM, PH.D., Lake Forest University.

ARNOLD E. ORTMANN, a Carnegie Museum, Pittsburg.

D. P. PENHALLOW,D.Sc„F.R.M.S., McGill University, Mi Montreal.

. H. M. RICHARDS, S.D., Columbia University, New York.

W. E. RITTER, PH.D., University of Cali ifornia, Berkeley.

ISRAEL C. RUSSELL, ELD. University of Michigan, Ann

ERWIN F. SMITH, S.D., U. S. Department of Agriculture, ae

LEONHARD STEJNEGER, LL.D., Smithsonian Institution, Washington.

W. TRELEASE, S.D., Missouri Botanical Garden, St. Louis.

HENRY B. WARD, PH.D., University of Nebraska, Lincol:

WILLIAM M. WHEELER, PED. a American Museum of "Natural History,

York.

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AMERICAN NATURALIST.

Vor. XXXIX. October, 1905. No. 466.

A PECULIAR VARIATION OF TEREBRATALIA

TRANSVERSA SOWERBY.

IH. W. SHIMER.

Tuis specimen (Figs. 2-5) of this very variable species differs

from tbe type as figured by Davidson (Fig. ı) in its more

elongate form, thicker valves, obscurity of plications, and less

development of the mesial sinus in the brachial valve.! Aside

from its normal variation the specimen is remarkable for its

extremely rugose surface due to the great inequality in the

development of growth lines.and also for the greatly abraded

umbo of the pedicle valve. This abrasion is so great that it

brings to view the unfilled cavity behind the buttress support-

ing the teeth which shows as a rounded hole, through which a

- bristle can be passed, on each side of the pedicle opening.

Dall, after an examination of this specimen, wrote us that it

is *an unusually worn and deformed specimen which has been

crowded by its fellows so as to grow out of shape and worn by

rocking on its pedicle until at least one quarter of an inch of

shell has been removed." In reference to the two holes above

1 For other figures and variations of this species see “ A Monograph on Recent

Brachiopoda ” by Davidson, Trans. Linn. Soc. London, ser. 2, vol. 4, and Amer.

Journ. Conch., vol. 6, pl. 6.

691

692 THE AMERICAN NATURALIST. (VoL. XXXIX.

mentioned he suggested that between the shell wall and the

buttress which supports the hinge in the dorsal valve there is a

cavity. With the growth of the shell and the buttress this

cavity is prolonged ; at times it is filled in part with shelly mat-

ter and at others it persists as a tube running up with the curve

of the umbo, one on each side of the pseudodeltidium. If these

tubes remain empty and the umbo is sufficiently abraded, they

will appear on the surface of the shell as two little holes. An

abrasion to this extent is very unusual; the nearest approach

to it noticed outside of this specimen was in Teredratula harlani

Morton where the former cavities though filled with shelly

- growth, yet showed faintly where weathered.

This specimen and two other pedicle valves of the same spe-

cies were collected by Professor W. O. Crosby of Massachusetts

Institute of Technology in the summer of 1904; they were found

on the beach at high tide at Kayak Village on Wingham Island,

Controller Bay, Alaska. They are now in the collection of the

Boston Society of Natural History, catalogue numbers 449 and

450.

The writer is indebted to Professor W. H. Dall of the United

States National Museum and Professor Charles Schuchert of

Yale University for the identification of this peculiar form.

MASSACHUSETTS INSTITUTE OF TECHNOLOGY.

No. 466] VARIATION IN TEREBRATALIA. 693

PLATE I.

Fic. 1 — The type specimen of Terebratalia transversa Sowerby. rg from pl. 16,

oc. London,

6, in “ A Monograph on Recent Brachiopoda,” Davidson, Trans. Linn.

ser. 2, vol. 4

Fic. 2.— sche view ei a opines " hes same dip from Wingham Island, Alaska,

l holes of the pedicle valve. Natural

B5 t

a impressions are much more faintly marked than the figures indicate.

n in Fig. 2, showing the great irregularity in the grow

1 ok

sho wing the

Fic. 3.— Side view of specimen se

of the shell. Natural size.

h : a E "n 1

e e pv

Fic. 4. Interior of brachial

ess and the large dental sockets. Natural si siz

Fic. 5.— Interior of pedicle valve of same s specimen eo the heavy character of the shell

about the umbo “er the largeteeth. Natural sı

STUDIES ON THE PLANT CELL. .— VII.

BRADLEY MOORE DAVIS.

SECTION VI. COMPARATIVE MORPHOLOGY AND PHYSIOLOGY

OF THE PLANT CELL.

WE shall devote this section to the discussion of a number of

topics some of which have received brief mention in the pre-

ceding papers of the series but with other.subjects will now

be considered in some detail. The material will be treated un-

der the following five headings : —

I. The simplest types of plant cells.

2. Comparisons of the structures of some higher types of

plant cell with simpler conditions.

3. Some apparent tendencies in the evolution of mitotic phe-

nomena.

Ac The diemii structures of the plant cell and their be-

havior in ontogeny.

5. The balance of nuclear and cytoplasmic activities in the

plant cell.

I. THE SiMPLEST Types OF PLANT CELLS.

There are three groups of plants which are conspicuous for

the simplicity of their cell structure. They are: the Cyano-

phycez (blue-green alga), Schizomycetes (bacteria) and the

Saccharomycetes (yeasts). All three groups have received

much attention and there has accumulated an extensive litera-

ture which we shall not attempt to treat in detail, since it has

. been handled very fully by the specialists in these subjects.

We shall, however, present the most important conclusions and

1 This paper concludes the series of studies on the plant cell. The author has

a number of complete sets of reprints of this and the earlier sections. Enquiries

may be addressed to Professor Bradley M. Davis, University of Chicago.

695

696 THE AMERICAN NATURALIST. (VoL. XXXIX.

try to give the present status of investigations in these most

difficult subjects.

Cyanophycee (Blue-green Algg).— The most recent and com-

prehensive papers on the cell structure of the Cyanophycez are

by Fischer ('97) Macallum ('99), Hegler (: o1), Bütschli (: 02),

Kohl (: 03), Zacharias (:00, :03), and Olive (:04). Olive gives

an especial clear analysis of the situation in this field of

investigation at the present time and an excellent historical

review of earlier literature may be found in Hegler (:01). The

discussions center chiefly around (1) the presence or absence of

a nuclear structure and its behavior in cell division, (2) the dis-

tribution of the blue-green pigment (phycocyan) and the struc-

ture of a possible chromatophore, and: (3) the nature of certain

conspicuous inclusions within the cell, called cyanophycin gran-

ules and slime globules. An outline in tabular form of the

views of some thirty investigators on these subjects is given by

Olive (:04, p. 10).

Writers from the earliest periods of cell Wades on the Cyan-

ophyceæ have recognized the presence of a central body in the

interior of the cell more or less sharply differentiated from the

peripheral region, which holds the coloring matter and certain

inclusions. The central body contains granular material which

stains and behaves in other particulars like chromatin. But as

a rule this granular material is.not confined within a membrane

or vacuolar cavity which has proved the most serious difficulty

to its acceptance as chromatin and the central body as a nucleus.

Then many investigators have not been able to satisfy them-

selves that the central body exhibits the phenomena character-

istic of nuclear division even in a simple form. Consequently

much doubt has been expressed as to its morphology and pos-

sible relation to a nucleus.

The most recent and detailed investigations have, however,

brought forward much evidence to the effect that the granular

material in the central body is chromatin which becomes organ-

ized into chromosomes that are distributed by a form of mitotic

division. In the vegetative cells, which generally divide rapidly,

the chromatin is never held within a nuclear membrane but in

young heterocysts and spores such inclosing membranes have

been found (Olive, : 04).

No. 466.] STUDIES ON PLANT CELL.— VIII. 697

Olive (:04) has given especial attention to methods of sec-

tioning and staining on the slide and presents the most detailed

account of the structure and behavior of the chromatin and the

simple apparatus which brings about the division of the central

body. The central body is made up chiefly of dense kinoplasm

with a fibrillar structure in which lie chromosomes that may be

counted and whose number is found to be constant in several

species. Thus there are eight chromosomes in a species of

Gloeocapsa and Nostoc and sixteen in certain forms of Oscilla-

toria Phormidium, and Calothrix.. The chromatin in some

cases was observed to be organized into what seemed to bea

simple type of spirem (especially clear in Gloeocapsa) within the

central body, and the chromosomes are formed by a concentra-

tion of material at certain points which are constant in the cells

of the same plant.

Olive found evidence that the chromosomes split during the

process of division of the central body and are gathered in two

groups at the ends of the achromatic structure which is gener-

ally flattened at the poles and conforms in other particulars to

the shape of the cells. The two sets of chromosomes are

finally separated by the cell wall which develops from the pe-

riphery during cell division and cuts the achromatic structure

in the middle region. That portion of the central body which

remains between the two sets of daughter chromosomes is

regarded by Olive as equivalent to the central spindle so well

defined in stages of anaphase and telophase in mitoses of higher

plants. The central body during this process of division has

certainly very much the appearance of a simple type of spindle

although there are not present the large fibers so characteristic

of nuclear figures in higher plants. Moreover it can scarcely

be held that the division is one of simple fusion when chromo-

somes are present in constant numbers and split into two groups

with each division of the cell. Olive believes that the achro-

matic structure, present during cell division, is a disc-shaped,

generally flat-poled spindle, densely fibrous in structure and that

the fission of the chromosomes and their separation into two

sets constitutes a true mitotic division of the central body, which

is a nucleus.

698 THE AMERICAN NATURALIST. [Vor. XXXIX.

Other authors as Scott (88), Hegler (:01), Bütschli (: 02),

and Kohl (:03), also believe that the central body is a nucleus

which divides mitotically but none has described the process as

so closely similar to nuclear division in higher plants as in the

account of Olive. Some of their results are criticized by Olive

as based on preparations in which the stain was not properly

differentiated or the sections were too thick. Among the recent

writers Wager (:03) stands alone as holding that the nucleus

divides directly (amitotically) by a process of simple fission.

Both Kohl and Wager conceive the chromatin as in a network

or convolute spirem which breaks up into segments which are

drawn apart, thread by thread, quite a different process from the

splitting of organized chromosomes. Other authors have held

that the granules in the central body were chromatin although

they were not willing to admit the structure as a nucleus. Thus

Macallum (’99) found that the central body contained phosphor-

ous and ‘masked iron" to a conspicuous degree and he, with

other investigators, has shown that this structure resists the

action of artificial gastric juice, solutions of pepsin, etc. These

chemical reactions are considered confirmatory of the theory

that the granular material is a proteid of a high order of or-

ganization such as would be expected of chromatin. However,

such chemical tests are very difficult to apply and do not seem to

the writer so important in establishing the nature of the central

body as does the careful study of its structure and activity during

cell division. The objection that the central body lacks a mem-

brane, universally present around resting nuclei of higher plants,

is not regarded as vital by Olive. In the first place such a

membrane may be found around the resting nuclei in young

heterocysts and spores and its absence in vegetative cells is

probably explained by the rapidity of the successive cell divi-

sions. There are some recent writers, as Massart (:02) and

Zacharias (: 00, :03) who are still unconvinced that the granules

in the central body are chromatin and that the structure is the

equivalent of a nucleus. Their papers and figures, however,

clearly show that they have failed to find the detailed structures

of other investigators.

Fischer (97) has been the most conspicuous opponent of the

No. 466.] STUDIES ON PLANT CELL.— VIII. 699

view that the cells of the Cyanophycez and also of the Schizo-

mycetes contain nuclei, taking a position in sharp opposition to

that of Bütschli ('96). Fischer’s conclusions were based on his

failure to find that differentiation of the protoplasm within the

cell demanded by the conception of the central body and the

activities of this structure during cell division as described by

other authors. He presented a sharp criticism of the conclu-

sions based on the reaction of stains in determining the nature

of protoplasmic structures, criticisms largely directed against the

investigations of Bütschli. He showed by some ingenious experi-

ments upon emulsions of albumen fixed on a slide that stain

reactions were a purely physical phenomenon. Thus the same

combinations of stains, such as saffranin and gentian violet, may

be made to give exactly opposite results in differentiating a mix-

ture of large and small globules of albumen when used in reverse

order. He attached no importance to the so called affinity of a

protoplasmic structure for a particular stain and would not accept

such apparent affinity as evidence of its chemical nature. The

fact that the central body takes chromatic stains did not seem to

him important evidence of its nuclear character and he was very

positive in his belief that the cells of the Cyanophycez do not

contain nuclei and that the central bodies should not be consid-

ered the phylogenetic forerunners of such structures.

This attitude of Fischer towards conclusions based on stain

reactions was later presented in more elaborate form in his cri-

tique ('99) on methods of fixing and staining protoplasm and has

had an important influence on methods of cytological investi-

gation and interpretation. The stain reaction is now regarded

as probably merely a physical phenomenon but an effective

means of differentiating protoplasmic structures. The deter-

mination of their morphology rests with an understanding of

their history and behavior in the activities of the cell. Although

Fischer general criticism of methods of cell research was

timely and in some instances richly deserved, nevertheless his

particular conclusions respecting the cell structure of the Cyano-

phycez and the Schizomycetes have not been sustained by

investigators who have followed the history of the protoplasmic

structures in the cells of these organisms.

700 THE AMERICAN. NATURALIST. (VoL. XXXIX.

We may pass now to the peripheral region of the cell which

holds the blue-green coloring matter of the Cyanophycee. A

number of investigators, as Wager (:03), Kohl (:03), Hegler

(:or), and Hieronymus ('92), have held that this pigment was

contained in minute granules distributed throughout the cyto-

plasm under the cell wall. These granules have at times been

termed chromatophores or plastids and Hegler has proposed for

them the name cyanoplastids. Other authors, especially Fischer

(97), Nadson ('95), Palla (93), and Zukal ('92) have been unable

to find these color-bearing granules and have believed the color-

ing matter to be uniformly diffused throughout the peripheral

region of the cell. Fischer has made a particularly thorough

study of the reactions of the pigmented region to various acids

in comparison with the chromatophores of higher alge and con-

cludes that no plastids are present but that the color is held in a

hollow cylindrical or spherical outer layer of protoplasm which

may be termed a chromatophore. Olive supports Fischer,

approaching the subject from a very different point of view. If

minute plastids are present they should be visible in fixed and

stained material and Olive is unable to find any trace of Hegler's

cyanoplasts. The granules of the outer region of the protoplast

seem to be colorless inclusions.

Perhaps the most confused part of the discussion on the

structure of the cell of the blue-green algze is that which deals

with certain inclusions. There are apparently two sorts which

are very common in the cells: (1) the cyanophycin granules

(Borzi) and (2) the slime globules. The cyanophycin granules

are very apt to lie along the cross walls in filamentous forms or

in other peripheral regions of the cell. They are generally

believed to be a form of food material and it has been suggested

that they are the first visible product of photosynthetic processes,

but their chemical nature is under dispute. The slime globules

lie more frequently in the interior region of the cell close to the

nucleus and frequently within this structure. They have been

termed nucleoli by some authors and also confused with chro-

matin. Besides these two bodies, other minute globules have

been described as oil or fat and some remarkable crystalloid

structures have been figured, especially by Hieronymus ('92).

No. 466.] STUDIES ON,PLANT CELL. VIII. 701

Indeed the entire subject is so confused that it does not seem

desirable for us to take it up in detail at this time, especially

since these inclusions are apparently all secretions or excretions

and not morphological features of the cell. The most compre-

hensive discussions of the subject will be found in the papers of

Hegler (: 01), Kohl (: 03), and Zacharias (: 03).!

Schizomycetes (Bacteria) —The history of research upon the

cell structure of the Schizomycetes has run in large part parallel

with that on the Cyanophycez. The clearest results have come

from. studies upon the larger forms of the sulphur bacteria,

especially certain species of. Beggiatoa, and on certain forms of

Spirillum. The more minute types and pathogenic forms in par-

ticular have proved very baffling because of their small size and

it can scarcely be said that we fully understand their cell struc-

ture. As in the Cyanophycez, investigators of the bacteria fall

into two groups: one holding that the Schizomycetes entirely

lack a nucleus and the other that there is present a structure,

often termed a central body, which is the equivalent of a nucleus.

Bütschli ('96, : 02) has been the most conspicuous advocate

of the latter view.. He described and figured clearly a central

body in the cells of Beggiatoa, Chromatium, and Spirillum with

the same organization as given in his account of that body in the

Cyanophyceze. The central body contains granular material

which Bütschli regards as chromatin and the structure is shown

in stages of division. Bütschli has no hesitation in giving the

central body the value of a nucleus. It lies within a peripheral

1Since the above was written a lengthy paper by Fischer, “Die Zelle der

Cyanophyceen " has appeared (Bot. Zeit., vol. 63, p. 51, 1905), too late to be

included in these reviews. Fischer has not changed his conclusions on the chief

points as discussed in his earlier papers. ‘The chromatophore is a closed cylin-

drical structure; the cyanophycin granules are proteid in character ; vil cogen and

another hoic des , anabzenin, are conspicuous substances in t cell; the

central body is not a nucleus but the seat of important metabolic processes con-

cerned with WR ra rates, and its contents and behavior in cell division

holo must clearly establish the proteid nature of the central body and

its contents para the“ so called” chromatin granules) before they can

expect the acceptance of their conclusions as to its nuclear character.

702 THE AMERICAN NATURALIST. [Vor. XXXIX.

region of protoplasm as in the Cyanophycex. There is of course

no blue-green pigment (phycocyan) in the cells of bacteria and

consequently no chromatophore but several sorts of inclusions

may be present in the protoplasm. The nature of some of the

inclusions is not clear and this subject has not been given as

much attention as in the Cyanophycez. It is significant that

this cell structure should be found so clearly in the Beggiatoa

since this organism seems very close to Oscillatoria in its mor-

phology. Some of the larger species of Beggiatoa may be

expected to yield conclusions similar to those of Olive’s investi-

gation on Oscillatoria if sectioned and critically stained, especi-

ally as the cells are very large in some forms and there is

probably less extraneous matter to complicate the interpretation

of the preparations.

As has been stated, investigations upon the smaller species of

bacteria and especially upon pathogenic forms have met with

great difficulties. These led at one time to the ingenious theory

of Bütschli (’90), followed by Zettnow ('97) that possibly the

entire protoplast had the value of a nucleus. That is to say,

an outer peripheral region of. cytoplasm had either never been

developed in these organisms or, if present, had become so

closely associated with the chromatin that it could not be dis-

tinguished as a special region of the cell. A peripheral region

of cytoplasm is represented in some of the larger forms by the

cilia and by accumulations of protoplasm at the ends of the cells,

especially clearly shown in Spirillum (Bütschli, '96; Zettnow,

97). Later Zettnow ('99) and Feinberg (:00) applying the

staining method of Romanowski, followed by several later inves-

tigators with improved technique (Nakanishi, :01, and others),

succeeded in differentiating a minute body in the cells of smaller

bacteria and pathogenic forms, which is regarded now as similar

to the central body of the sulphur bacteria and a true nucleus.

This structure is very minute since it occupies a portion of

these exceedingly small cells. Naturally it will be very difficult

to obtain any detailed knowledge of its structure and behavior

during cell division. But enough seems to be known to justify

the belief that differentiated nuclear structures are probably

present even in the smallest types of bacteria. A recent paper

No. 466.] STUDIES ON PLANT CELL.— VIII. 793

of Vejdovsky (: 04) describes and figures a simple type of spindle

in. Bacterium gammeri and Bryodrilus ehlersi with a separation

of two groups of chromatin granules during mitosis.

The chief critics of the conclusions that the cells of Schizo-

mycetes are nucleated have been Migula (’95) and Fischer.

The latter author in particular has devoted considerable attention

to the group especially in his paper of 1897 which is largely a

discussion of Bütschli's ('96) results on studies of the blue-green

algae and bacteria. Fischer considers the central body described

.by Bütschli in the sulphur bacteria as merely a vacuolate region

of the cell made conspicuous by the arrangement of the sulphur

grains and that the structure does not appear in cells which are

free from sulphur. The granular material, considered as chro-

matin by others, is regarded. by Fischer as reserve material.

The central body described by Bütschli in the cells of Spirillum

is stated to be a product of contraction. In general the same

criticism which Fischer applied to the methods of staining and

interpretation of structures in the Cyanophycez is presented for

the Schizomycetes. Fischer cannot justify Bütschli's ('90) view _

that the smaller bacteria are chiefly composed of nuclear sub-

stance, a view which probably has few if any followers to-day

and could scarcely claim to be more than a passing suggestion.

In short, Fischer finds no evidence of a nuclear structure in the

Schizomycetes but curiously ends by declaring that the group

has no affinities with the Cyanophycez but that its forms are

closely associated with the Flagellata.

Saccharomycetes (Yeasts).— The structure of the yeast cell

has been perhaps the subject of as long a series of investigations

as the cells of the Cyanophycez and Schizomycetes, and the

problems in both cases have many similar features. The chief

problem in the yeasts has concerned the presence or absence of

an organized nucleus or its equivalent in the form of some sim-

pler structure. The accounts range from a complete denial of

its presence to descriptions of a nuclear apparatus of considera-

ble complexity which passes through some rather involved activi-

ties during cell division. It is impossible for us to treat the

subject historically. We shall only consider the accounts of the

most recent investigators and try to determine the probable

704 THE AMERICAN NATURALIST. - (VoL: XXXIX.

bearing of these studies. An admirable review of the early lit-

erature is presented in Wager’s paper of 1898.

Wager (98) himself has made one of the most detailed studies

of the yeast cell and his conclusions on the presence of a

* nuclear apparatus " will be made the starting point of our dis-

cussion. The yeast cell contains a structure, termed by Wager

a *nuclear body," generally situated at one side, close to the

cell wall. This body resembles the nucleolus of higher plants in

its homogeneous structure and reaction to stains. Besides the

* nuclear body" Wager finds a vacuole always present which

contains granular material and is an important part of the nuclear

apparatus, This *nuclear vacuole" must be carefully distin-

guished from other vacuoles of the usual type which merely con-

tain glycogen. There are besides some globular bodies in the

protoplasm whose nature may be oil in some cases and proteid in

others. The “nuclear body” is always in close contact with the

“nuclear vacuole” but is never within it. The amount of granu-

lar material in the nuclear vacuole is variable but it sometimes

contains a dense mass. This content is believed to be chroma-

tin from the behavior to stains and insolubility in digestive

fluids. Sometimes the nuclear vacuole disappears but in such

cases the granular network is found in contact with the nucleär

body and sometimes distributed about it in a very regular man-

ner. The chromatic granular material appears then to be a per-

manent substance in the cell and always closely associated with

the nuclear body, sometimes distributed about it and sometimes

included within a special vacuole.

Wager concludes that the nuclear apparatus consists of (1) a

nucleolus (nuclear body) and (2) a store of chromatin in a net-

work, either enclosed in a vacuole in “close contact with the

nucleolus or lying freely about the nucleolus or sometimes

disseminated in granules generally throughout the cytoplasm.

Wager believes that the nuclear vacuole arises from the fusion

of numerous small vacuoles which lie around the chromatin gran-

ules which thus come to lie within a common vesicle. This

mode of origin seems reasonable from what we know of the

history of the nuclear vacuole which arises around the chromo-

somes that gather at anaphase of mitosis to form daughter

No. 466.] STUDIES ON PLANT CELL.— VII. | 705

nuclei in higher plants. The earlier investigators for the most

part failed to recognize the chromatic granules and network

and considered the nucleolar body (nucleolus) to be the nucleus

of the cell. Janssens and Leblanc ('98), however, described a

nucleus with a membrane containing caryoplasm and a nucleolus,

and other authors noted the vacuole and believed that it held

some relation to the nucleus.

Both the nuclear vacuole and the nuclear body (nucleolus)

take part in the process of bud formation. The bud appears on

the opposite side of the cell from the nuclear body and.the nu-

clear vacuole lies between. The bud contains at first cytoplasm

alone; then the nuclear vacuole begins to pass into it and the

nuclear body takes a position in the vicinity, between the

mother-cell and the bud.. The nuclear body now divides by

simple fission and one half enters the bud. The nuclear vacu-

ole gradually constricts and is drawn apart in the canal between

the two cells. The two daughter nuclear vacuoles and -nuclear

bodies then pass to opposite ends of the mother- and daughter-

cells respectively. If the nuclear vacuole is absent the chroma-

tin network is drawn apart so that a division is effected ina

similar manner.

At the time of spore formation, the chromatin is reported by

Wager to, become so closely associated with the nuclear body

that the two substances cannot be easily separated and behave

as one. The resultant structure elongates and divides by con-

striction and the subsequent divisions are of the same character.

Strands ef deeply staining protoplasm between the daughter

nuclei are of interest as suggesting the possibility of a simple

type of spindle. Wager describes the formation of spore walls

around the nuclei enclosing a portion of the protoplasm and

thus cutting the spores out from the remaining non-nucleate cell

contents. The details of this process are not known and might

prove very interesting since the process, from Wager's account,

would seem to be one of free cell formation without, however,

the characteristics described by Harper in spore formation

within the ascus. It should be more thoroughly studied for it

is possible that the division will be found to involve cleavage

furrows and really prove to be a type of segmentation by con-

striction (Section II, Amer. Nat., vol. 38, p. 453, June, 1904).

706 : THE AMERICAN NATURALIST. [Vor. XXXIX.

Several papers have appeared on the structure of the yeast

cell since Wager’s account of 1898. Marpmann (:02) and

Feinberg (:02) described much simpler conditions than are

reported by Wager, and recognize scarcely more than a deeply

staining body which they term a nucleus. Hirschbruch (: 02)

gives an extraordinary description, accompanied by diagram-

matic figures, of a nuclear structure and a body, staining red

and blue respectively, which are supposed to fuse previous to

the development of a bud, but the account is so unsatisfactory

as to merit little attention. Janssens (:03) reviews the work of

these investigators and others in comparison with his earlier

results (Janssens and Leblanc, '98). Guilliermond (:04) has

published the most, recent paper presenting more completely his

conclusions of an earlier investigation in 1902. `

Guilliermond's conclusions have some points of resemblance

to those of Wager. He finds a nuclear vacuole containing a

granular network believed to be chromatin and a nucleolar

structure. The entire body seems to be a true nucleus, not dif-

fering in its essentials from the nuclei of other fungi. Some-

times all the material in the nucleus seems to be condensed into

a central body, a sort of chromatin nucleolus (chromoblast)

somewhat resembling a similar structure in Spirogyra. Guillier-

mond figures the nucleus as constricting during the process of

budding, one part passing into the daughter cell. His figures

show clearly deeply stained material outside of the nuclear

membrane in a position similar to that of Wager’s nucleolar

body (nucleolus).

These points of agreement seem to justify at least in part

Wager’s account, but of course the peculiarities of both lead

one to suspect that there are important features in the structure

of the nucleus and in the events of nuclear division which have

not been determined. It certainly seems probable that chroma-

tin is present in definitely organized bodies (chromosomes) some-

times within a vacuole and sometimes lying around a nucleolar

structure. The latter also holds an intimate relation to the

. chromatin, which is frequently true in higher plants. There are

indications that a simple type of spindle is present at least in

the nuclear divisions during spore formation. In view of

No. 466.] STUDIES ON PLANT CELL.— VII. 707

Olive's results in studies on the Cyanophycez it does not

seem unreasonable to hope that more accurate staining of very

thin sections will bring the peculiarities of these accounts into

harmony with mitotic phenomena of higher forms.

The accounts of conjugation in yeasts (Barker, :or and

Guilliermond, :03) which were discussed under * Asexual Cell

Unions and Nuclear Fusions" in Section IV give no additional.

information on the essential structure of the yeast cell.

2. COMPARISONS OF THE STRUCTURE OF SOME HIGHER TYPES

OF PLANT CELL wiTH SiMPLER CONDITIONS.

Some of the most fruitful and interesting fields of investiga-

tion in cell structure are likely to be in those border groups

between the very simplest conditions of the lower alga and

fungi and the higher regions where the nucleus and processes of

mitosis have clearly the essential features which are generally

ascribed to this structure and its activities. At present the gap

seems very great between the simple conditions of the Schizo-

phyta and the groups of alge and fungi on the next higher

general level. But as a matter of fact we know almost noth-

ing of the nuclear structure in the lowest groups of the Chloro-

phyceze, z. e., among the simplest of the unicellular green algae.

It is rather remarkable that this region should have been

so neglected. |

The Nucleus.— Comparative studies on the nucleus naturally

treat chiefly of the chromosomes and nucleolus. One of the

most interesting features of more recent research on the nucleus

has been the steady accumulation of evidence indicating that the

nucleolus holds a very important relation to the chromatin con-

tent. There are types among the lower algae in which the whole

or a greater part of the chromatin is gathered into a dense nu-

cleolar body in the resting nucleus. Spirogyra is the best

known illustration of this condition and has been studied by

several investigators. Similar phenomena have been reported

by myself in Corallina (Davis, '98), by Golenkin ('99) for

Spheeroplea, and by Wolfe (:04) for Nemalion. Some nuclei,

however, particularly in the higher plants have nucleoli whose

708 ' THE AMERICAN NATURALIST.. [Vor. XXXIX.

substance does not seem to contribute directly to the chromo-

somes and these have been regarded as secretions within the

nucleus. Strasburger believed that such were masses of reserve

material drawn upon by the kinoplasm during the process .of

spindle formation. The term plastin has been applied to such

substance in the nucleolus and also in the linin as cannot be

directly connected with chromatin. A nucleolus may consist of

plastin alone, or have with this substance varying quantities of

chromatin. Nucleoli consisting of chromatin alone may be ex-

pected among the lower plants from the studies on Spirogyra,

Corallina, Sphaeroplea, and Nemalion. Plastin and chromatin

are probably closely related substances.

A recent paper of Wager (:04) indicates that the nucleolus

of some higher plants holds a far closer relation to the chromo-

somes than has been supposed and rather weakens Strasburger's

theory of the structure as a reserve mass drawn upon during

mitotic activities. This Study and recent papers by Miss Mer-

riman (:04) and Mano (:04) have all been upon the cells of root

tips while the conceptions of Strasburger and others have been

founded largely on the structure and behavior of the nucleolus

in the spore mother-cell during the mitoses of sporogenesis.

Wager treats of the root tip of Phaseolus, Miss Merriman of

Allium, and Mano of Solanum and Phaseolus. They are impor-

tant contributions to the subject of the nucleolus and should be

considered in any treatment of this structure. The papers

appeared too recently to be noted in our brief account of

the nucleolus in Section I which is consequently incomplete.

Wager's paper especially presents an excellent review of the

literature on the nucleolus in the plant cell.

Wager concludes that the nucleolus is really a portion of the

nuclear network and that the spirem is derived in part at least

from this structure. Material from the nucleolus then passes

into the chromosomes. Also, in the reconstruction of the

daughter nuclei the chromosomes are massed together at a cer-

tain stage and from this mass the nucleolus emerges, taking out

with it the greater part of the chromatin. Wager then con-

siders the nucleolus as a store of chromatin which must be

taken into account in theories of heredity based on the morpho- .

No. 466.] STUDIES ON PLANT CELL.— VIII. 709

logical independence of the chromosomes. Miss Merriman

reports the origin of the nucleoli as masses among the meshes

of chromatin from which they draw their substance. Mano, in

contrast to Wager, holds that the nucleoli appear as globules

independent of the chromatin network and later flow together

into a single body. The chromosomes are also believed by

Mano to be morphologically independent of the nucleolus and

if the latter furnishes material to the former it is not by the

emergence of strands as described by Wager. Mano then holds

the nucleolus to be an accessory structure without morphologi-

cal relation.to the chromosomes.

The theory of the individuality of the chromosomes is of

course vitally concerned with the problem of the morphology of

the nucleolus but this topic we have reserved for later treatment

under the caption : * The Essential Structures of the Plant Cell

and their Behavior in Ontogeny.” Tke- chromatin and nucleoli

within the nucleus of a higher plant lie in a vacuole whose fluid

content is bounded by a plasma membrane similar to that around

any vacuole in the cell. Lawson (:03) and Grégoire and

Wygaerts (:03) have emphasized this structural condition in

recent papers but the central idea seems to be an old one run-

ning through the writings of Strasburger from an early period.

We bring up these striking conceptions of nuclear structure

in the higher plants because it seems very probable that a much

clearer understanding of the problems will come through inves-

tigations upon the simpler conditions in the lower plants.

There, we may hope to find evidence of the primitive forms of

nucleolar and chromatic associations with perhaps some clues as

to the manner of the development of the higher types of struc-

ture. Thus the yeast cell, as reported by Wager ('98) with its

chromatin sometimes collected within a vacuole and sometimes

distributed in the cytoplasm and a nuclear body (nucleolus) in

close association with the nuclear vacuole, but not within, is of

the greatest interest as presenting intermediate stages in the

complexity of nuclear structure and illustrates what may be

hoped from further research among the lower forms.

The Chromatophore and Plastid.— In considering the great

‘variety of chromatophores and plastids exhibited among the

710 THE AMERICAN NATURALIST. [Vor. XXXIX. ;

thallophytes one notices at once certain features of their distri-

bution in various groups. The large chromatophores are charac-

teristic of the cells of simpler and more primitive groups and the

small plastids, numerous in the cells, are generally present in

types which are at a fairly high evolutionary level. There are

exceptions of course to this general statement but some of

these are probably significant of phylogenetic relations.

The evidence all indicates that the primitive type of chroma-

tophore was a large structure in the peripheral region of the

protoplast and with an ill defined boundary or occupying the

entire surface of the cell. This type of structure is at present

characteristic of chromatophores of the Cyanophyceæ and is also

present in numbers of the lower groups of green algæ. Thus

we may find many types in the Pleurococcaceze whose cells con-

tain a pigment so diffused that it is impossible to establish

definite limits and similar conditions often appear in the cells of

some of the higher algæ as in Hydrodictyon and certain simple

forms of the Ulothricaceze.

The simple diffused types of chromatophores of the lower

algae become replaced in higher groups either by sharply differ-

entiated structures of definite form and often showing internal

organization in the form of pyrenoids or by numerous plastids.

There is considerable evidence that the plastids have arisen by

the successive splitting or division of large organized chromato-

phores. The most highly differentiated chromatophores are

found in the Conjugales and the remarkable size and symmetry

of these cells is emphasized by the same peculiarities of the

chromatophores. They are generally so placed in the cells as to

give an almost perfect balance of protoplasmic structure. This

principle is especially clearly illustrated among the desmids and

in such forms as Zygnema and Mougeotia while even Spirogyra

illustrates the principle strikingly in the distribution of its spi-

rally wound chromatophores.

Plastids are characteristic of the Siphonales, Charales, most

of the Rhodophycez, the higher Phzeophycez, and all groups

generally above the thallophytes. It seems to be the type of

structure best suited to cell activities since with few exceptions

itis found in groups in the highest lines of plant evolution in

No. 466.] STUDIES ON PLANT CELL.— Vill. 71I

various directions. The only striking exceptions to this broad

principle are Anthoceros, whose cells contain each a single large

chromatophore, and Selaginella. Selaginella is especially inter-

esting for, while the cells of the meristematic region and young

organs contain but a single chromatophore, this structure may

divide later in some types to form a chain of discoid plastids in

older cells connected with one another by delicate strands of

protoplasm. Thus in the life history of certain species of Sela-

ginella we have plainly shown the change from a single chroma-

tophore to a number of plastids. It seems probable that this

history repeats in general outline the evolutionary history of the

condition characterized by numerous plastids within a cell from

a primitive type of cell structure with but a single chromato-

phore. Anthoceros and Selaginella may be regarded as forms

whose cells still retain the primitive conditions with respect to

the single large chromatophore.: There are somewhat similar

illustrations in the Rhodophycez as in Nemalion and Batracho-

spermum whose cells hold a single large chromatophore while

most of the more highly organized red alge have numerous

plastids. A beautiful series of stages illustrating the evolu-

tionary principles outlined above might be worked out in the

Phaophyce=.

What is the fundamental principle underlying the substitution

of numerous plastids in a cell in place of a single chromato-

phore ? The author believes that it must have relation to the

preservation within large cells of a certain balance of the meta-

bolic centers. The fission of a plastid is a process of constric-

tion and studies on Anthoceros (Davis, '99, p. 94) indicate

that the bounding cytoplasmic membrane exerts pressure upon

the elongating structure. It seems probable that the division is

due to the mechanical separation of material that is too bulky

for the most effective results of photosynthesis which in the

case of a single chromatophore are centered in a particular

region of the cell. By the division of a chromatophore into

numerous plastids the photosynthetic activities are distributed

among several centers and a much better balance results within

the cell. It is very interesting that the large elaborate chroma-

tophores with their peculiar internal differentiations, the pyre-

712 THE AMERICAN NATURALIST. [VOL. XXXIX.

noids and caryoids, should have been displaced by the much

simpler and apparently homogeneous plastids.

A comparative study of chromatophores and plastids from

the point of view of their evolutionary history is much to be

desired and such research would necessitate extensive studies

among the lower groups of alge and especially in the Proto-

coccales. Such studies would involve far more than the general

morphology of the chromatophore and plastid. The structure

and activities of the pyrenoid are a very important subject as

shown by the investigations of Timberlake on Hydrodictyon

and nothing is known of the function of the caryoid. A de-

tailed investigation of the chromatophore or plastid throughout

ontogeny is yet to be made.

The Cytoplasm.— There is no region of the plant cell whose

structure is more varied and as little understood as that pre-

sented by the cytoplasm with its diverse conditions. We have

throughout these papers held to the classification of Strasburger

that the cytoplasm may be separated into two forms: kinoplasm

and trophoplasm, which show certain structural peculiarities and

are characterized by very different forms of activity. While it

must be acknowledged that kinoplasm and trophoplasm are very

similar in certain regions of the cell and at certain periods of

the cell history, still the distinctions are in general clearly

marked.

Kinoplasm is homogeneous in structure, either minutely

granular or consisting of delicate fibrillæ composed of very

small granules placed end to end. The homogeneous condition

is characteristically shown in the three forms of plasma mem-

branes which cytoplasm places between itself and external or

internal surface contacts. The three membranes are: the outer

plasma membrane, the nuclear membrane, and the vacuolar

membranes. They are certainly closely related and probably

identical in structure and appear to be the natural expression of

protoplasm to contact with a fluid (water) medium. The fibril-

lar condition appears during mitosis and serves important func-

tions in the mechanism (spindle) through which the chromosomes :

are distributed and in most of the higher plants determines the

position of the cell wall that is generally formed with each

nuclear division,

No. 466.] STUDIES ON PLANT CELL.— VIII. 713

But the manifestations of kinoplasm during nuclear division

and also in relation to cilia-bearing surfaces are exceedingly

various and it is among these structures that our ignorance of

relationships and modes of origin is deepest. These kinoplasmic

structures have been described in various connections through-

out this series of papers and especially in Sections I, II, and

III, and need not be treated here. But the point which should

be emphasized in this connection is the necessity of the close

study of their simplest expressions in the lower regions of the

thallophytes.* The most varied forms of kinoplasm are in the

thallophytes where asters, centrospheres, and centrosomes ob-

tain and: where ciliated cells, presumably with blepharoplasts,

may occupy long periods of the life history. It is here that we

must search for information that will bring order out of the con-

fusion of our present accounts and insufficiency of knowledge.

The most vital problems relating to kinoplasm concern the ori-

gin and the events of the simplest types of mitotic phenomena

and the formation of cilia. We have a fairly clear understand-

ing of the general features of mitosis in the groups above the

thallophytes and their relation to the lower types and these will

be briefly treated in the following portion of this section under

the head: *Some Apparent Tendencies in the Evolution of

Mitotic Phenomena." But the events of mitosis among the

thallophytes are exceedingly various and difficult to understand

and nothing is known of their origin or relation to the simpler

conditions which must be present in the lowest regions of the

Chlorophyceze and in the Cyanophycez.

Trophoplasm comprises all of the cytoplasm included within

the plasma membranes. While this region does not give rise to

such highly differentiated cell organs as the kinoplasm, never-

theless some remarkably interesting structures are developed.

Coenocentra and Physodes are specialized structures of exceed-

ing interest and our ignorance of the latter is truly remarkable.

Nematocysts if trophoplasmic offer another attractive subject for

investigation. In a sense, chromatophores and plastids may be

considered trophoplasmic but their high grade of specialization

and fixity as cell organs gives them a certain independence of

other structures in the cell. Respecting the structure of the

714 THE AMERICAN NATURALIST. . VoL. XXXIX.

groundwork of trophoplasm, whether fibrillar, granular, or pre-

senting the structure of foam, botanical science has as yet fur-

nished very little systematic study and this field of research is

one of exceptional opportunity for the student of the plant cell.

The Cell Wall— The cell wall may be treated from two

points of view : either with respect to the strict chemistry of its

organization and development or more largely for the biological

and morphological features involved. The chemistry of the cell

wall is an exceedingly complex subject which has developed a

special literature of its own. In the substance termed cellulose

we are not dealing with a single body but rather with a large

group of closely related bodies. And besides the members of

the cellulose group there may be present foreign substances so

intimately associated with the carbohydrates as to resist very

severe treatment. We cannot even touch this phase of the sub-

ject ; a brief review of its complexities and problems is presented

by Beer (:04) and there are further references in Section I of

these “ Studies." :

There are, however, some biological features of the process of

wall formation, the morphological and physiological aspects of

the phenomena as they are related to protoplasm, which offer

some exceedingly interesting problems especially among the

thallophytes. It has long been a matter of dispute whether the

cell wall is a secretion from the surface of a plasma membrane

or is formed wholly or in part by the transformation of such a

membrane.

It seems to be established now that substances of the cellu-

lose groups are only formed in contact with plasma membranes,

that is, they are not formed actually in the interior of proto-

plasm although they may appear to lie in such situations. Thus

the material of the capillitium of the Myxomycetes which is of |

the same character as the chief substance in the exterior cover-

ing of the fructification, is laid down within vacuoles in the

protoplasm, and is therefore in contact with the surface of vacu-

olar plasma membranes precisely as the outer covering lies in

contact with the surface of the outer plasma membrane. The

morphological relation of capillitium and outer covering to the

surface of plasma membranes is therefore precisely the same.

No. 466.] STUDIES ON PLANT CELL.— VIII. 715

And similarly the cross wall which takes the position of the cell

plate at the end of mitosis is not developed from the transfor-

mation of a film of protoplasm but is laid down between two

surfaces that separate to form a thin vacuole which later spreads

to the edge of the cell and the wall is deposited between these two

membranes which are almost in contact. There are a number

of cases in which large strands or masses of protoplasm have

been described as changing directly into cellulose but it is prob- :

able that these examples upon further study will exhibit the

same relation of the cellulose substances to plasma membranes

as in the typical cases of wall formation. There are many inter-

esting examples of cellulose formation whose precise relation to

the protoplasm has not yet been determined.

Respecting the exact method by which a cellulose wall is laid

down by a plasma membrane there is very little real informa-

tion. It is clear now that the cellulose is not a secretion from

the plasma membrane comparable to a mineral shell. There is

much evidence that protoplasm is actually sacrificed in the de-

velopment of cellulose. There are numerous illustrations, as in

the tracheids and other cells empty of protoplasm, where the

final secondary thickenings are deposited as the protoplast grows

smaller and eventually disappears, a large part of its substance

evidently contributing to the deposits which are members of the

cellulose group. But of course it cannot be supposed that the

molecules of the proteids are changed directly into those of the

carbohydrates. Nevertheless it does seem clear that the carbo-

hydrates appear simultaneously with the disappearance of the

proteids and occupy the position formerly held by the latter. It

is probable that with the splitting up of the proteid molecule,

carbohydrate material is formed which displaces the proteid sub-

stances. So in a broad sense the cellulose deposit actually does

represent a transformation of a plasma membrane.

The evidence in general favors the view that the wall, lamellze,

and other deposits of cellulose only increase in amount when in

actual contact with a plasma membrane. Some apparent excep-

tions to this principle are easily understood. Thus cell walls or

portions of such may swell greatly and become much softer in

consistency and perhaps even mucilaginous. There are no

716 THE AMERICAN NATURALIST. . [Vor. XXXIX.

reasons for regarding such transformations as an actual increase

in the carbohydrate material for it is clear that the substance is

a body with a greater amount of water in its organization than

is present in the more usual forms of cellulose compounds.

But there are some cases which are not so easily understood and

perhaps the most widely known are the megaspore walls of cer-

tain species of Selaginella. These spores are remarkable for a

differentiation of the spore wall in which the outer layer seems

to be entirely separated from the inner by a space and yet is

able to increase enormously in size and take on marked pecul-

iarities of structure, but apparently without any relation to the

protoplast. It may, however, be justly questioned whether the

apparent space between the inner and outer wall is really a

cavity and may not be filled with plastic material which holds

the two walls in intimate organic relation to one another and to

the protoplast. Miss Lyon has recently given this subject at-

tention and announced her belief that the latter condition ob-

tains. Her conclusions will be awaited with interest.

As regards the way in which a cell wall increases in size we

are still limited to the two conceptions termed (1) growth by

apposition and (2) growth by intussusception. The first method

consists in the laying down of successive layers by the plasma

membrane and results in a thickening of the cell wall. It is of

course à comparatively simple process. Growth by intussuscep-

tion is a stretching or expansion of the substance which seems

to be greatly increased in quantity although the morphology of

the structure remains the same. The current explanation out-

lined by Nägeli assumes that new molecules of carbohydrates

are intercalated among the old. It seems more probable that

the increase in bulk is due to some modification or rearrange-

ment of existing molecules, involved, perhaps with an increase

of material but not through the actual intercalation of new

molecules of the same or original carbohydrates. The chem-

iia . i is so complex that great changes of

mie Aa no properties may be readily assumed which

ge the appearance of a structure without, how-

ever, necessitating the transportation of new carbohydrate sub-

stance to it directly.

. There are many forms, particularly among the lower plants,

where studies on the processes of wall formation are sure to

throw much light on the fundamental problems which we have

discussed. Anda particularly interesting study might be made

of the evolutionary history of the cell wall among the thallo-

phytes and in the modifications introduced when plants pass

from aquatic habits to aérial or terrestrial conditions. Our

attention has been chiefly centered on the structure of the pro-

toplast and the morphology and behavior of its parts. Weare

likely soon to give more study to the carbohydrate membranes

and walls and this subject is likely to be very fruitful for inves-

tigation.

3. SoME APPARENT TENDENCIES IN THE EVOLUTION OF

Mirotic PHENOMENA.

Our brief descriptions in Section II (Amer. Wat., vol. 38, p.

431, June, 1904) of the various kinoplasmic structures developed

during mitosis in different groups of plants brings up the prob-

lem in their relationships to one another, 7. e., the evolutionary

tendencies in the differentiation of mitotic phenomena. We

have seen that the thallophytes present an especially diverse

assortment of kinoplasmic structures associated with the spindle

and its method of development. The spindle fibers, whether

formed within the nuclear membrane (intranuclear) or arising

from without (extranuclear), are associated with centrosomes or

centrospheres to form asters in a number of well known types

as Stypocaulon, Dictyota, Fucus, Corallina, certain diatoms, the

ascus, and the basidium. Centrospheres are found in certain

phases of the life history of liverworts as in the germinating

spore of Pellia. A second type of kinoplasmic structure resem-

bling in certain features the aster but with some fundamental

differences has been termed the polar cap. The polar cap is an

ill defined region of kinoplasm, generally larger than a centro-

sphere and without clear boundaries, which forms a region for

the insertion of spindle fibers. Polar caps are well illustrated

in the mitoses of vegetative tissues and meristematic regions,

especially among the higher plants (pteridophytes and sperma-

718 THE AMERICAN NATURALIST. [Vor. XXXIX.

tophytes). They sometimes approach the centrosphere very

closely in their morphology.

The third and highest type of spindle formation in plants is

that illustrated in the mitoses within the spore mother-cell which

were given special treatment in Section III (Amer. Nat., vol. 38,

p. 725, October, 1904). In this remarkable cell the spindles

develop from a mesh of independent fibrilla which at prophase

more or less completely surround the nucleus. The poles of

the spindle arise by the grouping of cones of fibrillz so that a

single axis is finally established but without any kinoplasmic cen-

ters at the poles. This type of spindle formation which may be

termed the free fibrillar type is one of the most interesting

cytological peculiarities of plants. It has been found in all

types whose sporophytic phase terminates its history with a

spore mother-cell, although the accounts in the Hepatice are

not in full accord.

Is it possible to connect the various types of spindle formation

with one another and to establish any evolutionary tendencies in

the processes involved ; and have the different manifestations of

kinoplasm such as centrosomes, centrospheres, polar caps, free

fibrillar condition, and the mysterious structure called the ble-

pharoplast any genetic relation to one another? The confusion

is so great among the thallophytes that the author sees little

hope at present of establishing clearly any relationships between

the types of centrospheres and centrosomes with their systems

_ of radiations (asters) and we must patiently wait for more infor-

mation. And respecting the origin of these structures from the

simpler types of mitosis we are absolutely in the dark. But

the relation which polar caps and the free fibrillar type of spin-

dle formation bear to centrospheres is less perplexing and it

seems possible to define certain common features among these

structures which hold them together with a degree of unity in

their relations to mitosis. That phase of the subject will be

considered in this treatment. The Hepaticz as a group occupy

an interesting position with respect to the character of mitotic

phenomena at various periods of ontogeny, between conditions

in the pteridophytes, which are obviously similar to the sperma-

tophytes, and conditions in the thallophytes. This was brought

No. 466.) STUDIES ON PLANT CELL.— VII. 719

out by the work of Farmer whose accounts of centrosomes and

centrospheres in the germinating spores of Pellia and within

the spore mother-cell of various liverworts, together with his

account of a “quadripolar spindle" made it evident that the

group offered some very interesting cytological problems. They

led the author to the study Anthoceros (Davis, '99) and Pellia

(Davis, :01), investigations which have been followed by Van

Hook (:00) on Marchantia and Anthoceros, Moore (:03) on

Pallavicinia, Chamberlain (:03) and Grégoire and Berghs (:04)

on Pellia, while Ikeno (:03) has studied the processes of sperma-

togenesis in Marchantia.

My studies on sporogenesis in Anthoceros and Pellia led me

to conclude that the processes of spindle formation did not

differ in any essentials from those in the pteridophytes and sper-

matophytes. There are present two successive mitoses and the

spindles are formed from a surrounding mesh of fibrille devel-

oped from the kinoplasm associated with the nuclear membrane

and without achromatic centers (centrospheres or centrosomes).

They exhibit clearly the free fibrillar type of spindle formation

although in somewhat simpler form than in the pteridophytes

and spermatophytes. The poles of the spindles generally end

bluntly in areas of granular kinoplasm but these seem to me too

indefinite in form to deserve the designation of centrospheres

and such granular inclusions as may be present are too variable

in number and position to be termed centrosomes. There is

clearly present in Pellia during the prophase of the first mitosis

a four-rayed achromatic structure which is later replaced by a

typical bipolar spindle. This four-rayed kinoplasmic structure

is evidently the same as Farmer's “ quadripolar spindle” which

he described as associated with a simultaneous distribution of the

chromatin in Pallavicinia to form at once four daughter nuclei.

I was led to doubt this account and to suggest that the “quad-

ripolar spindle" might prove to be simply a phenomenon of

prophase associated with the peculiar four-lobed structure of

the spore mother-cell in the Jungermanniales. I stated my

belief that the distribution of the chromosomes during sporo-

genesis in all liverworts would be found to take place through

two successive mitoses after the usual manner. Moore (:03)

720 THE AMERICAN NATURALIST. [Vor. XXXIX.

has recently studied an American species of Pallavicinia and

has failed to confirm Farmer’s conclusions. He found the four-

rayed figure, which Farmer terms a “ quadripolar spindle," a

conspicuous feature of the first mitosis here as in Pellia but

there was no indication of a simultaneous distribution of quad-

rupled chromosomes to form four daughter nuclei as reported

by Farmer. The four-rayed figure was merely preliminary to

the first mitosis whose spindle at metaphase was bipolar and the

first mitosis was followed shortly by a second, so that Pallavi-

cinia offers no exception to the essential features of sporogenesis

as known in all groups above the thallophytes.

Farmer (Bor. Gaz., vol. 37, p. 63, 1904) has taken exception

to the restriction of the term spindle by Moore and myself to

the structure found at metaphase and holds that the four-rayed

structure is a part of the spindle apparatus. In this discussion

he appears to avoid the issue, which is not the broader or nar-

rower application of the term spindle, a mere matter of usage,

but concerns the fundamental character of the mitoses during

sporogenesis whether they are two in number and successive in

all forms or whether Pallavicinia presents an extraordinary ex-

ception in a distribution of the chromatin to form four daughter

nuclei simultaneously in the spore mother-cell. Farmer (:05)

has recently reaffirmed his view that the poles of the four-rayed

figure in Aneura and presumably in other Jungermanniales are

occupied by centrospheres and that sometimes a central body

(centrosomes) may be distinguished in each. This statement

involves again a matter of usage in which I should differ from

Farmer for my studies and those of. Moore do not seem to me

to justify the application of these terms to regions of kinoplasm

whose form is so ill defined and history so transient within the

cell.

These disputed points which were also discussed in: Section

IH (Amer. Nat., vol. 38, pp. 727-732, October, 1904) are of

importance in relation to the mitotic phenomena in other periods

of the life history of liverworts which will now be considered.

It may be stated, however, that other investigators who have

studied the processes of sporogenesis in the liverworts (Van

Hook, :00; Chamberlain, :03 ; Grégoire and Berghs, :04) sup-

No. 466.] STUDIES ON PLANT CELL.— VIII. 721

port my general program of sporogenesis with the free fibrillar

type of spindle formation. There seems to be little question

but that centrospheres are present and conspicuous in the early

mitoses within the spore of Pellia. They have been especially

studied by Farmer and Reeves (’94), Davis (:01), Chamberlain

(:03), and Grégoire and Berghs (:04). All of these authors

have agreed that asters are clearly defined in the early mitoses

within the spore and most of them: have termed the region of

kinoplasm in the center of the aster a centrosphere. The struc-

tures are less prominent in the third mitosis and are perhaps

replaced in later periods of the gametophyte history by kino-

plasmic polar caps. Polar caps are characteristic of the mitoses

in the seta of Pellia (Davis, :01). However, Van Hook has

described centrospheres with radiations at the poles of the

spindles of the archegoniophores of Marchantia, whose centers

sometimes contained centrosomes, and it is possible that the

centrosphere runs through a considerable period in the life his-

tory of liverworts. There is complete agreement that the cen-

trospheres when present arise de novo and independently of one

another during the prophase of mitosis and that they disappear at

telophase. Ikeno has, however, described centrosomes during

the mitoses within the antheridium which are said to divide and

pass to opposite sides of the nucleus where they become the

poles of the spindles. They cannot be found after the mitosis is

completed, but are described as formed de novo in the interior

of the nucleus and thrust through the nuclear membrane into

the cytoplasm previous to each mitosis. After the final divi-

sion in the antheridium, the centrosome remains to function

as a blepharoplast.

Thus we see that the liverworts present during their life

history an almost complete range of kinoplasmic structures

associated with the nuclear divisions ‚from centrosomes and cen-

trospheres to polar caps and that type of spindle formation

characterized by free fibrille gathered into cones but entirely

independent of definitely organized centers. There is also pres-

ent the blepharoplast. I emphasized this range of kinoplasmic

structure in my paper on Pellia and it seemed to me one of the

most interesting features of the liverworts.: In this paper

722 THE AMERICAN NATURALIST. (Vor. XXXIX.

(Davis, :01, p. 171) are outlined the changes in form which

kinoplasm may assume in the mitoses of the liverworts upon

which is based a theory of a cycle through which kinoplasm

may run in the history of a cell. On this theory, centrosphere,

polar cap, and the free fibrillar condition are all secondary devel-

opments from a primal finely granular kinoplasm which is the

only form of kinoplasm that is in any sense permanent in the

cell. This finely granular kinoplasm is always present in char-

acteristic form in the plasma membranes of the cell. The sub-

stance of centrospheres, polar caps, and fibrille arises from

accumulations of granular kinoplasm during prophase and these

Structures return to the same undifferentiated granular kino-:

plasm at the end of mitosis or become lost in the general

cytoplasm of the cell. :

The cycle is from an undifferentiated finely granular kino-

plasm through certain specialized conditions either wholly or

in part fibrillar in structure back to the granular state. The

centrosphere and polar cap are regions from which fibrillz de-

velop at least in part and to which they may remain attached as

to an anchorage. The polar cap is a less clearly differentiated

kinoplasmic center than the centrosphere but does not differ .

from it in the essentials of its organization. It seems to me that

the two structures are very closely related in the liverworts and

that in this group we may readily conceive the polar cap as de-

rived from the centrosphere. The free fibrillar type of spindle

formation is a step farther in the direction of such a distribution

of the kinoplasm that no very positive centers for the develop-

ment of the spindles may be distinguished. The four-rayed

structure (quadripolar spindle) so characteristic of- the spore

mother-cell in the Jungermanniales represents a group of four

temporary centers for the formation of fibrille and there is

clearly a gathering of kinoplasm at these points but the regions

are so vague in outline as hardly to justify the designation of

centrospheres. From the fibrillar state, kinoplasm returns to

the finely granular condition by the contraction of the fibers

w pepanen ops to some common area.

nuce We DEL e chromosomes of the daughter

er in part at least a nuclear mem-

No. 466] | STUDIES ON PLANT CELL.—VIII. 723

brane. Or the area may be a cell plate whose halves on division

finally merge with outer plasma membranes of the cells. The

spindle fibers which cut out the spore areas in the ascus form

the basis of a plasma membrane. Thus the fate of all kinoplas-

mic fibrille seems to be a final return to the undifferentiated,

finely granular condition so characteristic of plasma membranes

which according to this theory is the condition from which they

arose. |

Thus I believe the liverworts present rather striking evidence

of a relationship between the centrosphere, polar cap, and the

free fibrillar condition of spindle formation and establish an

evolutionary tendency from the first two types of kinoplasmic

differentiation towards the latter. The free fibrillar type of

spindle formation is found in a very simple form in this group,

sometimes with temporary centers, as in the four-rayed figure

(quadripolar spindle) of prophase, whose poles have accumula-

tions of kinoplasm in the position of centrospheres. The polar

caps are likely to prove a much simplified type of centrosphere

whose kinoplasm is no longer gathered to form conspicuous

spherical centers. With respect to the problem of the homol-

ogies and nature of the blepharoplast, the liverworts furnish as

yet no material assistance and this structure stands at present

as one of the most interesting puzzles of plant cytology. As

stated in the beginning, the variety of centrosomes and centro-

spheres with and without. radiations in various types of the thal-

_lophytes seems to me too confusing to promise an understanding

of their relationships at present.

Grégoire and Berghs (:04) have interpreted the structure of

the mitotic figure in the germinating spore of Pellia in a very

different manner from the accounts of Farmer, Chamberlain,

and myself. They consider the asters to arise through a re-

arrangement of the cytoplasmic network around the nucleus.

They affirm that there are no true centrospheres nor any ac-

cumulations of granular kinoplasm to constitute the centers of

origin for the spindle fibers or the radiations around the poles of

the spindle. The centers of the asters (‘‘vésicules polaires”)

are said to have a vesicular structure and neither they nor the

nucleus contributes to the building up of the spindle which is

724 THE AMERICAN NATURALIST. [Vor. XXXIX.

developed entirely out of the cytoplasmic network. The au-

thors are unable to distinguish a kinoplasm distinct from the

general network of the cell. These are vital points of differ-

ence which are fundamental to the understanding of mitotic

phenomena and rest of course on matters of fact. The chief

points at issue concern the structure and development of the

asters and the nature of the material at their centers. My own

studies and those of Farmer and Chamberlain have convinced

me that there is an accumulation of substance (kinoplasm) in

the centers of the asters and polar caps to such an amount that

. it must be regarded as a definite structure in the cell and its

morphology and relations to the spindle have certainly justified

us in considering it as similar to the centrosphere of the thallo-

phytes.

4. THE EssENTIAL STRUCTURES IN THE PLANT CELL AND

THEIR BEHAVIOR IN ONTOGENY.

grouped as cytoplasmic and nuclear. The greater part of the

cytoplasm, including that which is ter

organization peculiar to itself and v

the plasma membranes. This Structure has been described as

alveolar or of the nature of foam and sometimes fibrillar and

with various large granular inclusions. The cytoplasm also con-

tains the characteristic organs termed plastids. The conspicu-

ous structures of the nucleus aré: the chromatic elements

med trophoplasm, has an

ery different from that of

No. 466.] STUDIES ON PLANT CELL. — Vill. 725

appearing as chromosomes during mitosis and the nucleoli.

These structures are so easily recognized and play such impor-

tant parts in the events of nuclear division that they command

attention at once as the essential elements in the nucleus. The

nucleus may also contain other material such as linin which,

however, does not seem to have a fixed form or behavior in the

cell. Finally there are certain kinoplasmic structures, as cen-

trosomes, centrospheres, and blepharoplasts, whose behavior

throughout cell history has been much discussed. We shall now

consider the most important of these structures, those which

seem essential to the cell in ontogeny.

The outer plasma membrane naturally retains its morphologi-

cal entity throughout all cell divisions with such slight changes

as when new parts are intercalated into its area through the

vacuoles that are utilized in the segmentation of protoplasm.

Vacuolar membranes are constantly shifting and cannot be fol-

lowed during cell division excepting in such cells as have one

large central vacuole (the tonoplast of De Vries). Sucha cen-

tral vacuole is much more characteristic of old cells and tissues

than of young or embryonic regions. There is certainly no

reason to suppose that it has organic existence through any very

extended period of the life history. The nuclear membrane

becomes lost during the prophase of mitosis and there is much

evidence that its kinoplasm contributes in some cases to the

formation of spindle fibers. Thus the nuclear membrane disap-

pears as a structure in the cell during mitosis and new vacuoles

are formed around the assemblages of daughter chromosomes

during telophase, leading of course to the formation of fresh

nuclear membranes at their surface of contact with the sur-

rounding cytoplasm.

There is perhaps no region of the cell protoplast that presents

such different appearances through long periods of the cell his-

tory as the trophoplasm. This is largely due to the varying

character of the inclusions which are not in themselves proto-

plasmic but which give a mixed structure to the trophoplasmic

regions of the cell. The inclusions may be carbohydrate or pro-

teid bodies held within spaces in the trophoplasmic groundwork

or they may be globules of oil or fatty substances. These

726 THE AMERICAN NATURALIST. | [Vor. XXXIX.

inclusions occupy small spaces in the trophoplasm which are

essentially vacuoles. There is also a class of granular inclusions

of a proteid nature which probably represent material in very

close organic relation to the substance of protoplasm. Tropho-

plasm does not then have so clearly defined a type of structure

as do the other regions of the protoplast but it is hardly probable

that its essential nature changes very materially throughout the

life history. The organization of trophoplasm is itself a matter

of dispute but the prevailing views favor an alveolar or foam

structure with a fibrous character at times somewhat resembling

the texture of sponge.

Ever since the classical investigations of Schimper upon the

plastid it has generally been held that these structures are per-

manent organs of the cell, reproducing by fission, and carried

along from one cell generation to the next with as much per-

manence as the nucleus. Schimper discovered plastids in the

oóspheres of certain spermatophytes and in a variety of embry-

onic tissues and concluded that the structures passed from

parents to offspring as leucoplasts when no trace of color could

be found in the reproductive cells or embryonic tissues. There

has been, however, no systematic study of the plastid through-

out the life history of higher plants and in most of the green

thallophytes there are reproductive phases, such as resting

spores, where we have no knowledge of the structure or distri-

bution of the chromatophores in the cell. It is very important

that the plastid be investigated with the same degree of atten-

tion which has been given to the nucleus, and that it be fol-

lowed through all periods of the life history in forms where the

color becomes greatly modified or is absent in the reproductive

cells and embryonic (meristematic) regions of the plant. Any-

one who has studied the embryonic tissues of plants will realize

the difficulties of the investigation which will probably involve

the development of methods of technique, especially of staining,

somewhat different from those generally employed in cell

studies.

We may now consider the elements in the nucleus and their

behavior during ontogeny. This is one of the most interesting

subjects in cell studies, for the importance of the chromosomes

No. 466] STUDIES ON PLANT CELL.— VIII. 727

and chromosome history in relation to problems of development,

heredity, hybridization, and variation is clearly understood, and

these subjects have already been treated in Section V, “ Cell

Activities at Critical Periods of Ontogeny in Plants.” Also

some recent papers on the nucleolus of which Wager's (:04) is

the most comprehensive, have brought this structure into very

close relation with the chromatin content of the nucleus, and the

nucleolus must now be considered in any treatment of the chro-

mosomes. The problems hinge on what is termed the individu-

ality of the chromosome, which is the question whether or not

the chromosome is a structural entity maintaining its independ-

ence completely through each and all of the cell divisions in a

life history. There is also involved the view that the chromo-

somes have come down from a line of ancestral structures,

reproducing by fission in every mitosis throughout the history

of the race. |

There are two extremes in the views on this exceedingly

interesting conception and also an intermediate position. The

one extreme has recently been set forth by Boveri (:04) in a

very clear statement. This view regards the chromosomes as

structural entities, possibly elementary organisms, which main-

tain an organic individuality and independent existence in the

cell. They are further regarded as in their typical form when

present as rods or short filaments during mitosis. Their be-

havior in the resting nucleus is one of great metabolic activity

which affects their morphology for the time being.

Those who are inclined to doubt the individuality of the chro-

mosomes and to hold off from a full acceptance of the theory,

base their attitude on the extreme difficulty or perhaps impossi-

bility of following the chromosomes as entities through the rest-

ing nucleus from one mitosis to another. These difficulties are

well known to those who have studied chromosomes even in

nuclei which are most favorable for the investigation of their

morphology. The chromosomes which enter the daughter

nuclei from a mitosis generally lose their form and the chroma-

tin becomes so distributed on a linin network or in a nucleolar

structure that the outlines of the original structures become

quite lost. Mottier (:03) in his recent studies on the spore

728 THE AMERICAN NATURALIST. ` (VoL. XXXIX,

mother-cell of certain angiosperms has emphasized these points

and Grégoire and Wygaerts (:03) have also shown the difficul-

ties of following the chromosomes in the resting nuclei of the

root tip and spore mother-cell of Trillium, stating that the struc-

tures become resolved into an alveolar network.

On the other hand Rosenberg (:04) claims that the chromo-

somes may be clearly recognized in the resting nuclei of some

forms and cites Capse//a bursa-pastoris as a particularly good

illustration. In this plant the chromosomes are described as

small granular bodies scattered throughout the nucleus in fixed

number at various stages of ontogeny. Thus there are 16 in

cells of the gametophyte and 32 in those of the sporophyte

while 48 of these bodies were counted in the nuclei of the endo-

sperm as would be expected if these nuclei are descendants of a

triple fusion in the embryo-sac. Similar conditions are reported

in other forms and there is considerable evidence giving weight

to the view that chromosomes may be actually followed through

all periods of the nuclear history in some favorable types.

Apart from the actual demonstration of the chromosomes in

the resting nuclei and their recognition as structural entities

through successive cell divisions there is much general evidence

in support of the theory of the individuality of the chromosomes.

This evidence lies in the nuclear fusions of fertilization and the

mitoses of processes of segmentation that follow where the

chromosomes are known to remain separate and have been dis-

tinguished as maternal and paternal. Also, as we have seen

from the discussions of reduction phenomena at sporogenesis

and the behavior of the chromosomes in hybridization, there are

good reasons for believing that maternal and paternal chromo-

somes remain separate all through the sporophyte generation

and are distributed to the offspring during sporogenesis. The

Importance of these events in the minds of all investigators has

rested very largely on the behavior of the chromosomes and has

led to the very general assumption that they must stand for

units of organization and may be counted as constant factors in

the problems of heredity. It is not necessary to adopt Boveri's

extreme views to hold still the theory of the individuality of the

chromosomes. Nor is it necessary to assume that the structures

No. 466.] STUDIES ON PLANT CELL.— VIII. 729

have a distinct organization which holds throughout the life his-

tory. The form of the chromosomes certainly does change with

different periods of the cell’s history especially within the rest-

ing nucleus and yet the centers of chromosome activity may

always be present to organize the chromatin into a new set of

elements for the next mitosis. It is perhaps difficult to believe

that the chromatin granules (chromomeres) find their way back

to the same chromosome with the prophase of each mitosis but

the existence of chromosome centers may be readily conceived

within the resting nucleus which would hold the number of chro-

mosomes true to the cell’s history.

With respect to the nucleolus there is abundant evidence that

the structure is not a permanent organ of the cell. When con-

taining chromatin, the nucleolus is found in its characteristic

globular state only during the resting condition of the nucleus.

Its chromatic substance passes into the chromosomes at pro-

phase of mitosis and the nucleolus generally disappears before

metaphase. Or if any substance is left after the chromosomes

are formed the remaining structure either gradually dissolves or

is thrust forth bodily into the cytoplasm surrounding the mitotic

figure where it disappears sooner or later. The nucleolus in

higher types of mitosis never divides to pass on with the chro-

mosomes to the daughter nuclei, but such a history is reported

in the yeast cell. If the nucleolus has any function in heredity,

as has been claimed (Dixon, ’99), such function must relate to

the chromosomes which contribute to its substance or derive

material from it. Besides the nucleoli which are composed

wholly or largely of chromatin, there are also those which seem

to have little if any relation to the chromosomes. Such are

well known in the spore mother-cells of higher plants and no

investigator has been able to connect these with the formation

of chromosomes as Wager (:04) has been able to do in the root

tip. It was upon nucleoli of this class that Strasburger founded

his theory that the structure was a mass of reserve material

utilized by the kinoplasm during mitosis in the process of spindle

formation. Such nucleoli generally fade away during the pro-

phase of mitosis and either entirely disappear or the remaining

substance is thrust out into the cytoplasm where it may some-

730 THE AMERICAN NATURALIST. [Vor. XXXIX.

times be recognized as deeply staining globules (the so called

extranuclear nucleoli).

There is left for our consideration that group of kinoplasmic

structures termed centrosomes, centrospheres, and blepharo-

plasts which, when accompanied by radiations, are called asters.

Some authors regard these structures as homologous and believe

them to be present in one form or another as permanent organs

of the cell in certain types (see discussion of Ikeno, :04).

Against this view stand the well established facts of an increas-

ing list of forms, both animals and plants, in which these struc-

tures unquestionably arise de novo at certain periods in the cell’s

history. To the author this evidence seems insurmountable and

he cannot believe that the aster is in itself a permanent organ

of the cell. We shall not take up the subjects of relationships

here for such discussions have proved of little profit except in

special cases where the various types of structure are found in

closely related forms or in the same life history, and these have

scarcely been studied at all. We know so little about the rela-

tionships in the thallophytes, where relationships must be sought

if present at all, that a satisfactory treatment of the subject is

hardly possible at present. One point seems to have escaped

attention.in the writings of those who have discussed the cen-

trosome problem. The active elements of the asters are not the

central structures (centrosomes, centrospheres, or blepharoplasts)

but the fibrillae which play such important parts as spindle fibers

or cilia. This fibrillar condition of kinoplasm has a fixed place

in the cycle of cell division appearing with each mitosis and at

the time of cilia formation, but the fibrille are not permanent

structures of the cell. There is some evidence that the centro-

somes, centrospheres, and blepharoplasts are merely regions for

the development and attachment of these fibrille and as such

may stand as the morphological expression of fibrillze-forming

dynamic centers rather than as organs which actually induce the

development of fibrille.

No. 466.] STUDIES ON PLANT CELL.—VIIL. 231

5. THE BALANCE OF NUCLEAR AND CYTOPLASMIC ACTIVI-

TIES IN THE PLANT CELL.

Two regions of the cell are sharply distinguished from one

another with respect to both morphology and physiology. They

are the nucleus and the cytoplasm. The nucleus soon dies if

isolated from cytoplasm and the latter, lacking a nucleus, cannot

be kept alive indefinitely unless it be in organic connection with

a nucleated mass of protoplasm. The necessary connection

may be only through delicate strands, as was established by

Townsend ('97), and also seems to be illustrated in the instances

of intercellular protoplasm which Michniewicz (: 04) reports are

connected by delicate fibrillee (plasmodesmen) with neighboring

cells. Some very interesting adjustments of the nucleus and

cytoplasm to one another have been reported in a series of

investigations of Gerassimow beginning in 1890. His most

recent papers of the past year (Gerassimow, :04a, :04b) pre-

sent a general summary of his studies and constitute a very im-

portant contribution to the subject. They will furnish much of

the material for this discussion.

Gerassimow has found that the cells of Spirogyra and other

members of the Conjugales offer admirable material for the

study of the relations between the nucleus and cytoplasm, and

throw important light on the functions, physiological activities,

and interdependence of both structures. By subjecting fila-

ments of Spirogyra during cell division to a temperature of

o° C. or treating them for a short time to the anesthetic influ-

ence of ether, chloroform, or chloral hydrate it is possible to

arrest the processes of mitosis at different stages with the result

that the protoplasm may become variously distributed in the

daughter cells. (1) A daughter cell may be formed lacking a

nucleus but containing a portion of the divided chromatophore

in a peripheral layer of cytoplasm. (2) A single cell may con-

tain the two daughter nuclei either separated from one another

or more or less intimately associated and perhaps wholly fused

depending upon how far the processes of mitosis have pro-

gressed before the cells have been subjected to the shock of the

732 THE AMERICAN NATURALIST. [Vor. XXXIX.

experiment. (3) Binucleate cells may continue their growth

with subsequent mitoses which when treated as before may give

daughter cells with three nuclei and one nucleus respectively or

with two each or indeed a cell containing four nuclei. Further-

more these nuclei may fuse with one another to give structures

witha greatly increased chromatin content. (4) In place of the

non-nucleated cells there may be formed chambers containing

cytoplasm and chromatophores, but without nuclei, which remain

in open communication with the nucleated companion protoplast

because the cell wall is not formed entirely across the mother-

cell.

Gerassimow has made some extended observations on these

various types of cells, and presents his results in many elaborate

tables and diagrams. We can only give an outline of his con-

clusions. (1) Cells which come to contain unusually large

nuclei through the suppression of mitosis or by the reuniting of

partially divided daughter nuclei increase proportionally in size

and their further cell division is postponed. The nuclei of such

cells have of course the peculiarity of an increased amount of

chromatin content. The large nuclei may later fragment into

two or more structures which separate and generally come to

lie at a distance from one another in the cytoplasm. The frag-

ments finally lose their powers of reproduction and exhibit

marked evidence of degeneration. (2) Cells which lack nuclei

may form starch in the usual manner in the presence of light

and exhibit for a short time a weaker general growth than nor-

mal nucleated cells. The power to develop a gelatinous sheath

also becomes markedly weakened. Finally there result a de-

crease in the volume of the cell, a fading of the chromatophore,

and conditions which lead to eventual death. (3) Chambers

which lack nuclei but are in protoplasmic union with nucleated

cells may be contrasted sharply with the non-nucleated cells.

They exhibit a much stronger growth for a longer time and with

a greater power to form starch, although not so marked as in

the nucleated cells, and the chromatophores retain their color.

There is also a conspicuous development of the gelatinous

sheath.

Haberlandt, Klebs, Pfeffer, Strasburger, and others have dis-

No. 466] STUDIES ON PLANT CELL. — VII. 733

cussed the relations of the nucleus to the surrounding proto-

plasm with respect to both dynamics and morphology. Klebs

(88) indeed anticipated some of the work of Gerassimow, study-

ing the non-nucleated cells of Zygnema and Spirogyra and

noting the ability of their chromatophores to form starch in

considerable quantities but the inability of the protoplast to add

to the cell wall. Klebs was able to keep these non-nucleated

cells alive in a sugar solution for from four to six weeks. But

for the most part the discussions of the balance of nuclear and

cytoplasmic activities in the plant cell have been very general in

character.

Some principles have been, however, widely held for several

years and may be summarized. The necessity of the nucleus to

the life of the cytoplasm has been clearly understood but the

studies of Klebs and Gerassimow indicate that the nucleus is not

directly concerned with the process of photosynthesis which

apparently may go on in non-nucleated cells as long as the cyto-

plasm retains a certain degree of vitality. A non-nucleated cell

may enlarge slightly but it is not probable that the amount of

protoplasm is increased. An especially interesting feature of

non-nucleated cells is the inability of the outer plasma membrane

to form cellulose walls or outer membranes. But the very inter-

esting studies of Townsend (97) have shown that this power

may be retained provided the non-nucleated mass of. protoplasm

is connected by delicate cytoplasmic fibrils with a nucleated

mass. It thus seems clear that the membrane-forming possi-

bilities of the outer plasma membrane are absolutely dependent

upon dynamic relations with the nucleus. While the chromato-

phore may carry on the processes of photosynthesis independ-

ently of the nucleus, nevertheless the general health of the cell

requires the activities of the latter so that the nucleus becomes

necessary to any extended photosynthetic work.

It has frequently been stated that the size of the nucleus is

directly proportionate to the amount of cytoplasm in the cell.

There are many favorable illustrations of this statement, as the

extraordinarily large eggs of the gymnosperms, especially the

cycads, whose nuclei are by far the largest in the plant kingdom.

And in general an increase in the amount of cytoplasm is accom-

734 THE AMERICAN NATURALIST. [Vor. XXXIX.

panied either by a marked enlargement of the nucleus with a

corresponding increase in the chromatin content or by mitoses

which distribute to the cytoplasm a greater number of nuclei

whose sum total of material is very much greater than before.

Conversely a sudden increase in nuclear material through nuclear

fusions either sexual or asexual is followed almost immediately

by general cell growth and increase in the amount of cytoplasm.

However, such fixed growth relations between nucleus and cyto-

plasm can hardly be an established physiological law for certain

highly specialized sperms have an insignificant amount of cyto-

plasm proportionately to the chromatin that is contained within

the gamete nucleus. It is evident that the interrelations of the

nucleus and the cytoplasm are so intimate that the growth activi-

ties of the one must benefit the other, but that this principle

can be formulated in definite mathematical ratios seems im-

probable. :

The dependence of the nuclei upon favorable situations in the

cytoplasm is clearly shown in cells when a partial or general

nuclear degeneration takes place. Thus during the processes of

oögenesis in the Peronosporales, Saprolegniales, and in Vau-

cheria there is present a period when the most of the numerous

nuclei within the oögonia begin to break down and finally

become disorganized. The causes of the nuclear degeneration

are not entirely clear but apparently the organ is unable to

supply all of the nuclei in their respective situations in the cyto-

plasm with the conditions necessary. for their life. There is con-

sequently a sort of struggle for existence among these numerous

nuclei and only those that are favorably placed in the cell are

able to survive. In all forms the surviving nuclei occupy a situ-

ation in the center of the masses of protoplasm which are to

become the eggs and those that break down are at or near the

periphery of the cell. In several genera (e. g., Albugo, Perono-

spora, Pythium, Sclerospora, Saprolegnia, and Achlya) the sur-

viving nuclei seem to owe their good fortune to a very close

association with the cytoplasmic structure termed the caenocen-

trum. The coenocentrum is a clearly differentiated region of

the cytoplasm and is probably the morphological expression of a |

dynamic center in the eggs of these fungi. Stevens’ ('99, : OI)

No. 466.) SICDIES OM PLANT CELL.—VIHL. 735

studies on Albugo showed that the coenocentra exert a chemo-

tactic influence upon the nuclei in their vicinity, drawing them

towards the mass of granular material in this favored region of

the cell and it is clear that they are greatly benefited in this

situation since they increase in size while the nuclei at the

periphery break done. This subject is discussed in detail in my

paper on Saprolegnia (Davis, :03, pp. 240-243) a form which

also illustrates exceptionally well the same principles of a sur-

vival of certain nuclei among many which degenerate, because of

their favorable position in the central region of the eggs in close

proximity to coenocentra. There are then undoubtedly regions

of the cell more favorable for the nutrition of nuclei than others

and the positions of these may be marked by morphological

characters as illustrated in the caenocentra. That similar dyna-

mic centers may also be present when there is little morphologi- ,

cal evidence of their existence is indicated in the processes of

oógenesis in Vaucheria (Davis, :04) which exhibits the same

principles of extensive nuclear degeneration as are found in the

Peronosporales and Saprolegniales and the survival of a single

nucleus in the oógonium, apparently because it comes to lie in a

mass of granular cytoplasm near the center of the oógonium.

736 THE AMERICAN NATURALIST. (VoL. XXXIX.

LITERATURE CITED IN SECTION VI, * THE PLANT CELL."

BARKER.

:01. A Conjugating Yeast. PAZ. Trans. Roy. Soc. London, vol. 194,

p. 467.

BEER.

:04. The Present Position of Cell-wall Research. Mew Phytologist,

vol. 3, p- 159.

BOVERI.

:04. Ergebnisse iiber die Konstitution der chromatischen Substanz des

Zellkerns. Jena, 1904.

BÜTSCHLI.

à Ueber den Bau der Bakterien und verwandter Organismen. Leip-

zig, 1890.

BUTSCHLI.

'96. Weitere Ausführungen über den Bau der Cyanophyceen und Bak-

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BUTSCHLI.

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CHAMBERLAIN.

:03. Mitoses in Pellia. Bot. Gaz., vol. 36, p. 29.

Davis. ]

'98. Kerntheilung in der Tetrasporenmutterzelle bei Corallina officinalis

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'99. The Spore Mother-cell of Anthoceros. Bot. Gaz., vol. 28, p. 89.

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:03. Odgenesis in Saprolegnia. Bot. Gaz., vol. 35, pp. 233, 320.

:04. Odgenesis in Vaucheria. Bot. Gaz., vol. 28, p. 81.

Dıxon.

'99. The Possible Function of the Nucleus in Heredity. Annals of

Bot., vol. 8, p. 269.

FARMER AND Moore.

:05. On the Maiotic Phase (Reduction Division) in Animals and Plants.

Quart. Jour. Micr. Sci., vol. 48, p. 489.

FARMER AND REEVES.

^ On the Occurrence of Centrospheres in Pe//ia epiphylla Nees.

Annals of Bot., vol. 8, p. 219.

No. 466.] STUDIES ON PLANT CELL.— VIII. 737

FEINBERG.

:00, Ueber den Bau der Bakterien. Centralb. f. Bak., pt. 1, vol. 27,

P. 417.

FEINBERG.

:02. Ueber den Bau der Hefezellen und über ihre Unterscheidung von

einzelligen thierischen Organismen. Ber. d. deut. bot. Gesellsch.,

vol. 24, p. 567.

FISCHER.

'97. Untersuchungen über den Bau der Cyanophyceen und Bakterien.

Jena, 1897.

FISCHER.

'99. Fixirung, Fárbung, und Bau des Protoplasmas. Jena, 1899.

GERASSIMOW.

:04a. Zur Physiologie der Zelle. Bull. Soc. Imp. Nat. Moscou, no. 1.

GERASSIMOW.

Ueber die Grösse des Zellkerns. Beih. z. Bot. Centralb., vol. 18,

GOLENKIN.

'99. Ueber die Befruchtung bei Spheroplea annulina und über die

Structur der Zellkerne bei einigen grünen Algen. Bull. Soc. Imp.

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GRÉGOIRE AND BERGHS.

La figure achromatique dans le Pe//za epiphylla. La Cellule, vol.

21, p. 193

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:03. La reconstitution du noyau et la formation des chromosomes dans

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Recherches cytologiques sur les levures. Rev. Gen. Bot., vol. 15,

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'92. ptos zur Morphologie und Biologie der Algen. Cows Beitr.

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Kinsnnnucn

Die Fortpflanzung der Hefezelle. Centralb. f. Bak., pt. 2, vol. 9,

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: 03. Beiträge: zur Kenntniss der pflanzlichen Spermatogenese ; die

738 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

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'88. Beiträge zur Physiologie der Pflanzenzelle. Unters. a. d. bot. Inst.

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:03. The Behavior of the Chromosomes in the Spore Mother-cells of

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No. 466.] STUDIES ON PLANT CELL.— VII. 139

NADSON.

'95. Ueber den Bau des dasa aie aman Scripta Botan.

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77-

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Abhand. a. d. Gebiete d. Naturwis-

740 THE AMERICAN NATURALIST. (VoL. XXXIX.

. ZACHARIAS.

Ueber die Cyanophyceen. Jahrb. d. hamburg. wissensch. Anstal-

ten, vol. 21, p. 49.

ZETTNOW.

'97 Ueber den Bau der grossen Spirillen. Zeitsch. f. Hyg., vol. 24, p

72.

ZETTNOW.

'99. Romanowski's Färbung bei Bakterien. Zeitsch. f. Hyg., vol. 30,

pif.

ZUKAL.

'92. Ueber den Zellinhalt der Schizophyten. Ber. d. deut. bot. Gesellsch.

vol. 10, p. 51.

DIADASIA PATTON; A GENUS OF BEES.

T. D. A. COCKERELL.

THE genus Diadasia was first described by Patton in the

Bulletin of the United States Geological Survey (vol. 5, p. 475).

The type is the Melissodes enavata of Cresson, which, as

Patton showed, is nearer to Anthophora than to Melissodes.

The genus occurs in our southwestern States, and is, undoubt-

edly, of neotropical derivation. Ashmead has recently placed

it as a synonym of the South American Ancyloscelis Latreille,

but it appears to me to be sufficiently distinct.

Our species of Diadasia have not hitherto been tabulated, and

as I have now seen all the species but one, I offer tables for

their identification. The species of Cresson are in the collec-

tion at the Philadelphia Academy ; I have been permitted to

borrow cotypes from that institution, through Mr. Viereck, and

this has enabled me to clear up several doubtful points. — Ez-

technia toluca (Melissodes toluca Cresson) and Daszapis ochracea

Ckll., are included in the table, as the first has for some years

stood in our lists as a Diadasia, while the latter is often mis-

taken for a species of that genus.

FEMALES.

Hair of head and thorax above short and dense, orange fulvous ; abdomen

with four clean cut bands of fulvous tomentum on a black ground ; outer

side of basal joint of hind tarsi with very long, strongly plumose, dark

chocolate-colored hairs ; inner side of this joint with shining dark ferru-

ginous hair ; en red ; "m all dark; front rough with very close

punctures ; sumichrasti (Cresson).

Hair of thorax not hk a: or if ronk abdomen not thus banded 1.

1. Scopa on outside of hind legs dark gray or blackish (in €— am: on

basal part of tibize.) 2.

Scopa on outside of hind SER white, or not gray or r blackish 4-

2. Very small; less than 8 mm. long; abdomen with narrow Het of

tomentum on apical margins of segments; mesothorax and scutellum

741

742 THE AMERICAN NATURALIST. (VoL. XXXIX.

minutely, iras ipsc punctate all over, therefore rough and not

shining j Entechnia toluca (Cresson).

Larger ; at DA over 3 mm. ong; ; carers well punctured but shin-

ing. x . : : : $:

3. Large and ei ER 12 mm. Misi or more

D. bituberculata ( Cresson).

Smaller ; about 10 mm. long, or less . i : afflicta (Cresson).

4. Very large species, about 15 mm. lon megamorpha Cockerell.

Large stout species, about 13 mm. Te hai of thorax above ochraceous

or fulvous, with the disc bare ^ : . > i . LA

Smaller species, less than 12 mm. long . 7-

5. Hind spur of hind tibia straight or practically so; pee more one

punctured, the large punctures stronger enavata (Cresson).

Hind spur of hind tibia strongly bent at end i ciypei less Pe punc-

tured, the large punctures weaker 6.

6. Legs dark red; abdominal beitiedho 3 ad 4 with: a narrow “apical

fringe, the rest thinly hairy ; ; australis (Cresson).

Legs black ; abdominal segments 3 and 4 with lateral areas where the sur-

face is raised and shining black, the hair on it being very sparse and

dark . : australis opuntie (Cockerell).

7. Anterior edge = abdasiiea! bills curved, the basal part of the seg-

ments dark; comparatively large and broad form: hind spur of hind

legs curved st end : australis rinconis (Cockerell).

Anterior edge of Danaina RN, not curved, the pubescence, except at

margin, uniformly distributed ; smaller forms

8. Hair on inner side of basal joint of hind tarsi light anda: ; abdo-

men entirely covered with yellowish tomentum Dasiapis ochracea Ckll.

Hair on inner side of basal joint of hind tarsi fuscous or black 9.

9. Face broad, eyes scarcely converging below; eyes narrow, especially

above; mesothorax shining, impunctate in middle, at sides with large

scattered punctures; abdomen broad, with narrow ochreous hair-bands

on hind margins of segments 2 to 4 A . laticauda Cockerell.*

Eyes broader and shorter, distinctly converging below ; mesothorax dul-

ler, the sides with very numerous feeble minute punctures

diminuta (Cresson).

Larger than the two last (11 mm. long) and at once separated from them by

having much fuscous or black hair on the abdomen ; there are ochreous

marginal hair-bands SUM ^ i j friesei Cockerell.

MALES.

Hair of face black .

Hair of face not black.

1. Apex of abdomen truncate; us very iub ; maxill palpi not

fringed with hair; size very small : . Entechnia toluca (Cresson).

M ( u:

No. 466] GENUS DIADASIA. ; 743

Apex of abdomen bidentate

. Abdomen above with much black tay on dud r PPE hind ne

second 5 ; ; i ‘ X

Abdomen aisé Mibi black bor : 6.

Large ; at least 13 mm. long ; apical teeth et doian nee ‘and

divergent . bituberculata (Cresson),

Smaller ; about 10 mm. bos: apical teeth of abdomen small and close

together

: m

Hind tibie dide bat ER not ERBEN NE bud joint “ak hind

tarsi dark ferruginous, long, slender, and curved, its apex not produced,

the hair on its inner side orange ; maxillary palpi not fringed with hair,

except a little tuft at the end of second joint; teguls light rufous

sumichrasti (Cresson).

Hind tibize greatly swollen, narrowing to a very slender base, shaped

something like a wine-bottle ; basal joint of hind tarsi dark, not so long,

with black or dark fuscous hair on inner side

. Tegulz dark but decided red; second jubinargindi cali S eed

above; hair of mesothorax white . afflicta (Cresson).

Tegulz piceous : second ipm o cell icd narrowed above ; hair

of mesothorax and scutellum gray . afflicta perafflicta Cockerell.

6. Basal joint of hind tarsus ending in a long process; species covered

with gray hair; iege er with no Tee of "UE hairs, but second

joint ciliate . :

Basal joint of hind tarsus not ending i in a ie process ; 8.

7. Larger forms . : . australis (Cresson).

Smaller, down to about Io mm. ind : darrai rinconis (Cockerell).

8. Very large, about 16 mm. long . megamorpha Cockerell.

Rather large, length over 10 mm., the ee more or less ochrace-

ous on thorax, sometimes quite fulvous ; facial eh longer than

broad . ^ : à i à : e.

Small, ques Tus on io mm. . x : À ; 10.

‚9. Hair of thorax more or less fulvous . ; i nido (Cresson).

Hair of thorax paler . ; enavata var. densa (Cresson).

10. Abdomen above shining m nass hairy, not banded ; face broad,

orbits little converging below (distinctly less than in diminuta

nitidifrons Cockerell.

Abdomen hairy, the hind margins of the segments banded

diminuta (Cresson).

Abdomen covered with appressed white tomentum

spheralcearum Cockerell.

D. albovestita Provancher, I have not seen. It was described

from the female; length just over 8 mm,, flagellum reddish

beneath, tegulae brownish, margins of abdotinal segments pale

yellow and covered with dense whitish pubescence ; apex red-

744 THE AMERICAN NATURALIST. [Vor. XXXIX.

dish brown. It must be similar to D. spheralcearum, but the

antennz are differently colored.

The following species are not considered valid : —

D. tricincta Provancher, from California, is said by Fowler to

be a synonym of enavata. This cannot be, from the descrip-

tion; but it is not apparent that it differs from afficta. D.

nerea Fowler, from California, is nigrifrons Cresson ; D. cinerea

Fowler, from California, is &ztuberculata Cresson. Fowler can

hardly be blamed for describing these as new, as when he pub-

lished his paper Cresson's species were supposed to belong to

Melissodes. D. ursina (Cresson) is enavata. D. apacha (Cres-

son) is diminuta. The types of apacha have been in some

liquid, presumably alcohol, and this accounts for part of their

characters. I formerly separated the specimens of the Middle

Sonoran zone as apacha, leaving those of the Upper Sonoran as

diminuta; but the comparison of specimens from various locali-

ties appears to show that the characters relied upon are too vari-

able to serve for specific distinction.

Two forms are new: —

Diadasia afflicta (Cr.) subsp. perafflicta n. subsp.

d.— Tegulz piceous ; second submarginal cell scarcely narrowed above ;

bair of mesothorax and scutellum gray.

9.— This sex does not materially differ from true a/ffzcta.

Hab.— Clark Co., Kansas, 1962 ft, May (F. H. Snow, 1191); Hamilton

Co., Kansas, 3350 ft. (F. H. Snow, 460); Wallace Co., Kansas, 3000 ft.

(F. H. Snow, 852). Three females, from the same three localities, are

numbered 851, 1197, and 445.

Diadasia spheralcearum n. sp.

d.— Length 7} mm.; like D. diminuta Cr., but with shorter, perfectly

white pubescence, and a narrower, more parallel-sided abdomen; the

pubescence of the abdomen, instead of being loose and suberect as in male

diminuta, is appressed (except on first segment) and covers the surface ;

aside from the pubescence, the hind margins of the segments are them-

selves white; the apex is bidentate, the teeth being like those of diminuta,

but rather larger; hind legs constructed as in diminuta ; shining hairless

triangle of metathorax much smaller than in diminuta ; posterior part of

mesothorax almost nude; tegula: subhyaline, ferruginous, dark at base;

antennz entirely black.

No. 466.] GENUS DIADASIA. 745

Hab.— Between Las Cruces and Mesilla Park, New Mexico, at flowers

| of Spheralcea fendleri lobata (Wooton), middle of August (Cockerell). It

was accompanied by Macroteropsis latior (Ckll.).

The distribution of the species in States, etc., so far as known,

is as follows: —

Mrxico.— D. diminuta Cr.; sumichrasti Cr. ; enavata Cr. (Lower Cali-

fornia). .

CALIFORNIA.— D. albovestita Prov.; afflicta Cr. (tricincta Prov.) ; nigri-

frons Cr.; bituberculata Cr.; nitidifrons Ckll.; Zaticauda Ckll.; friesei

Ckl.; exavata Cr.; diminuta Cr. (Palm Spring, Davidson); australis `

rinconis Ckll.; australis opuntie Ckll.

NEVADA. — D. bituberculata Cr.

ARIZONA.— D. diminuta Cr. (Bill Williams’ Fork, Snow ; Grand

Canon, Hopkins); australis rinconis Ckl. (Bill Williams’ Fork and Oak

Creek Cañon, Snow) ; enavata Cr. (Oak Creek Cañon, Snow).

New Mzxico.— D. diminuta Cr.; spheralcearum Ckll.; australis Cr.;

australis rinconis Ck. ; enavata Cr. ; megamorpha Ckll.

Trxas.— D. australis rinconis Ckll. (part of Cresson's original austra-

lis, as shown by a 9 cotype) ; ezavata Cr.; enavata v. densa Cr. (a color

variation merely) ; aflicta Cr.

Kansas. — D. australis Cr. (Wallace Co., and Morton Co., Snow) ;

‘enavata Cr. (Wallace Co., Snow) ; diminuta Cr. (Hamilton Co., Snow);

afflicta perafflicta Ckll.

CoLoRADOo.— D. enavata Cr. (Lamar, Snow, Palisade, Gilette, Jules-

burg, Ball, Trinidad, Titus) ; enavata v. densa Cr. (Rocky Ford, in beet

field, P. K. Blinn); diminuta Cr. (Fort Collins, Trinidad, Colo. Agric.

Coll.) ; australis Cr.

D. sumichrasti Cr., is peculiar for the densely punctured

mesothorax, but the blade of maxilla is broad at base and nar-

row apically, as in true Diadasia. The maxillary palpi are long,

6-jointed. The sexes do not look much alike, but close com-

parison confirms their identity.

D. australis and its subspecies may be found visiting the

flowers of Opuntia. The small species, diminuta and its allies,

are addicted to the Malvacee. D. megamorpha (9) was

recorded from the flowers of Spheralcea angustifolia, but the

plant was really S. fendleri lobata, which had not then been

differentiated.

UNIVERSITY OF COLORADO,

BOULDER, COLORADO.

NOTES AND LITERATURE.

GENERAL BIOLOGY.

Driesch’s Naturbegriffe und Naturteile.' — This introduction to

the author’s philosophy of nature in a sense completes his systematic

empirical and theoretical treatment of biology, for the present volume

is, as he remarks, on the one hand the conclusion of his theoretical

biological work and on the other the presentation of the results of

investigations which transcend biology and even natural science

itself.

In his earlier books: Die Lokalisation morphogenetischer Vorgänge,

Analytische Theorie der organischen Entwicklung, Die organischen

Regulationen, Die * Seele” als elementarer Naturfaktor, Driesch has

discussed with insight the chief facts and principles of morphogene-

sis, even to the development of mind, in their relations and their

theoretical bearings. He now attempts a philosophy of nature, but

he has not used the title Materphüosophie because he feared that the

word philosophy might prevent the reading of the book by those for

whom it was written! Certainly he has ground for his suspicion

that most biologists have little interest in the concepts of reality,

constant, energy, measure, substance, entelechy which are analyzed

in the book.

The morphology of certain concepts which are of fundamental

importance in biology as well as in other natural sciences is a brief

characterization of Naturbegriffe und Naturteile. Those who care to

know what a philosophically inclined biologist thinks concerning the

structure and functions of the basal concepts of his science will be

interested in Driesch's work.

RM Y.

De Vries’ Species and Varieties? — The widespread interest

which has been aroused by the discoveries of Professor de Vries

makes the publication of this book an important and welcome event.

! Driesch, T oet lim sae Naturteile. Analytische Untersuchungen

zur reinen und em Nat "schaft. Leipzig, Englemann, 1904. 8vo,

viii + 239

? de Sls Hu ugo. Species and Varieties, their Origin by Mutation, edited by

D. T. MacDougal. Open Court Pub. Co., Chicago, 1905. 8vo, xviii + 847 pp.

747

748 THE AMERICAN NATURALIST. [VoL. XXXIX.

It is a matter of congratulation that we should now have, in English,

a discussion of the mutation theory and the line of thought which

led the author to put it forward, as well as an account of the experi-

ments on Lamarck’s Evening Primrose which has figured so largely

in the habilitation of the theory. Not indeed that this volume is to

be regarded as a translation of his Muzations-theorie, for without the

great amount of detail found in that work it treats the subject in a

broader way, aiming to bring out the mutation concept with sufficient

specific illustration to support the principles enunciated. After the

introductory chapter, which is of a historical nature, the discussion

of what are termed elementary species affords the topic of several of

the succeeding ones. Here we find a highly illuminating treatment,

which, in connection with what is said later about varieties, serves to

give a clarified conception of the import of the Linnean group or

collective species. That the latter are, indeed, an abstract idea, an

average as it were of a number of types grouped together, is brought

sharply to the attention. The modern taxonomist who is in sym-

pathy with this idea must at once see a new significance to the

segregations whicb are constantly and often of necessity being made

from the older forms which have been considered species. Elemen-

tary species are contrasted with varieties, in that they differ in more

than one respect and possess qualities which are distinctly new,

while in varieties the whole character difference may usually be

expressed by a single term and which, as the evidence goes to show,

do not possess any really new qualities. Most varieties arise in a

negative way, by the loss of some quality, and much more rarely do

they appear to be positive, possessing some feature new to them-

selves, which, however, is to be regarded as the reappearance of a

character seen in allied forms. Moreover, these characters are,

whether of à positive or of a negative nature, physiologic units and

appear and disappear singly. From this the development of the

author's line of thought leads him to the consideration of atavism

and the associated subject of hybridism. In discussing true atavism

all cases which might be confused with it that arise from hybridism,

or from varieties which annually produce sports, are to be excluded.

Atavistic tendencies in this strict sense are found to be very rare,

and while reversionary forms may often be widespread in the sense

of ERBEN aphical distribution, it is found that this is due to bud propa-

gatıon. For what the author calls false atavism he introduces a new

dps Ee uae ee to carry the idea of chance spatial contiguity,

which results in spontaneous and often undetected crosses. Under

this head then will come many of the instances of so called atavism.

No. 466.) NOTES AND LITERATURE. 749

Continuing the subject of bybridism we find again a difference

between. elementary species and varieties in the way in which they

behave when crossed. In crossing varieties all the characters are

paired, though some may be latent, and the progeny follow the Men-

delian law of splitting. Such crosses may be termed bisexual to con-

trast them with the unisexual crosses of elementary species. The

latter species differing in one or more unit characters, which are not

paired as in the first case, the result is a hybrid offspring which is

constant.

Having brought out the differences of elementary species and varie-

ties along the lines indicated, the author next inquires into the ques-

tion of the origin of new forms and here again shows that the behavior

of the two are unlike and that * sports" originating from varieties do

not introduce anything really new. To treat this last-named topic

the author has been constrained to coin a new term to designate

varieties which produce “sports " in each generation and these he has

called *eversporting varieties." The wide range of variability seen

in such forms is due to the presence of mutually excluding characters,

by reason of which the forms swing from one extreme to the other.

In most cases, however, latency of the more or less absent character

not being complete, there are intergrading forms found. Thus such

sports are not in reality new forms. The appetite of the reader hav-

ing been whetted by this as it were introductory matter, the discus-

sion of the origin of new forms in the production of elementary species,

that is mutation, is attacked with the greater zest. Here indeed is the

climax of the book, for which the reader has been carefully prepared

by what has gone before.

The subject is introduced by an account of the peloric toadflax

and the origin of double flowers, but of course the major interest

lies in the description of Professor de Vries’ minutely careful pedi-

gree cultures of CEnothera lamarckiana, Lamarck’s Evening Prim-

rose. It is not necessary here to recount the manner in which the

author came to experiment on this plant, or the manner in which the

experiments were carried on. In this country we are already familiar

with much of this from work done here, which looks to corroboration

and extension of Professor de Vries’ all-important observations. It

is sufficient to say that from this plant, under closely guarded condi-

tions of culture, several markedly distinct forms or mutants were

seen to arise and that these mutants have through successive genera-

tions bred true to their newly originated characters. Several princi-

ples or laws regarding mutation are deduced as follows. New

750 THE AMERICAN NATURALIST. (Vor. XXXIX.

elementary species appear suddenly, without intermediate steps.

New forms spring laterally from the main stem. New elementary

species attain their full constancy at once. Some new strains are

evidently elementary species, while others are to be considered as

varieties. The same new species are produced in a large number

of individuals. The mutations take place in nearly all directions.

The great difference between this and the Darwinian theory of the

origin of species is that here we have new forms which are to be

recognized as specifically distinct, arising in perfectly constant form,

by sudden leaps, or more properly mutations, rather than by contin-

uous slow variations. This and the fact that many individuals, whole

species indeed, are mutating simultaneously, must profoundly modify

the Darwinian concept. It is superfluous here to enter further into

this discussion or to point out how in other ways our ideas must be

rearranged to be consonant with these new facts. That the question

is completely solved no one, probably the author least of all, would

be prepared to admit, but that much light has been thrown on the

matter can hardly be questioned. It has been said somewhere that

while Professor de Vries has given us a Mutation Theory he has not

given us a Theory of Mutation. That may indeed be true, but let

us at least be thankful that here we have this question of the origin

of species at last within the field of experimentation. Perhaps it

will be possible for us to determine later what are the predisposing

conditions or influences which make for mutation, whether or not

there is any definite periodicity to the phenomenon. Not least im-

portant, too, is the bringing of the whole matter within the scope of

physiological inquiry, and the insistence that morphological tests un-

confirmed by physiological ones are only provisional. There is

bound, of course, to be considerable misconception as to what really

are and what are not mutations, and the intuitive plant-breeder will

no doubt be tempted to lay too great confidence on the scientific

value of his own experiments, yet in this way too the book, if under-

standingly read, will prove of the greatest value. It cannot be too

often stated that the confidence one has in the results of Professor

de Vries is that his were pedigree cultures guarded from contamina-

tion with the greatest care and with the complete ancestry of his

plants minately recorded from the time he undertook the work.

Bienen T no see for any scientific investigator pro-

odio 1 er Im o research in a loose or careless way after

Ser re S yet it ought to, and no doubt will, stimulate

0, themselves, add something to the sum of

No. 466.] NOTES AND LITERATURE. 751

knowledge in these matters. The book, while necessarily somewhat

technical at times, is by no means beyond the comprehension of the

general reader, who knows even a little about plants.

H. M. R.

ZOÖLOGY.

Sedgwick's Text-book of Zoülogy.'— The second volume of Sedg-

wick's Zext-book of Zoology is devoted to amphioxus and the ver-

tebrates. 'The volume, which contains over 7oo pages, may be

described as a revised expansion of the vertebrate portion of Claus

and Sedgwick. The expansion has been in part due to the addition

_ of materials on fossil vertebrates which were very inadequately dealt

with in the older text-book. The chapter on the Cephalochorda

deals almost exclusively with Amphioxus lanceolatus, the structure

and development of which is most admirably portrayed. Here,

however, the description ends, for almost nothing of value is given

concerning the natural history, distribution, or taxonomy of this im-

portant and interesting group of animals. In fact we are told that

the phylum contains only a single genus, Amphioxus, a statement so

conservative as to be misleading. The remaining chapters treat of

the vertebrates proper and contain as a rule well balanced descrip-

tions of the larger and smaller groups of this phylum reminding one

of the treatment accorded them in Claus's classic text-book except

that Sedgwick gives us an adequate account of the fossil representa-

tives. In fact the striking feature of this new text is the complete

absorption of paleontology into the body of zoólogy, a logical and

natural consequence of the growth of these two sciences. In another

respect, however, the new volume is strikingly out of touch with

recent work; it is almost without reference to animal physiology.

Although the recent results of comparative physiology are by no

means as ripe for incorporation into à general zoólogical text as those

of paleontology, they are certainly far too important to be omitted

from such a work as Sedgwick's and they are assuredly as truly a

l Sedgwick, A. A Student's Text-book of Zoilogy. Vol. II. London, Swan,

Sonnenschein and Co., 1905. 8vo, xvi + 705 Pp» 333 figs.

752 THE AMERICAN NATURALIST. [Vor. XXXIX.

part of zoólogy as the systematic and morphological matters that fill

the pages of this otherwise excellent work. From a mechanical

standpoint the book is well put together. A convenient arrangement

of small and large type helps to give light and shade. An excellent

index has the added convenience of indicating by the use of expo-

nents whether a name is found in the upper or lower half of the

page. Typographical errors are relatively few though Rabl-Rückhard

is misspelled on page 193 and its hyphen is omitted on page 321.

The illustrations are mostly familiar if not actually threadbare and

for some strange reason almost all from the older Claus and Sedg-

wick are much less satisfactorily printed than in the earlier work.

Notwithstanding such shortcomings, the volume as a whole has very

much for genuine commendation, though its size promises to put the

work when completed on the shelves of the teacher rather than in

the hands of the pupil.

G HP,

Aldrich’s Catalogue of North American Diptera.! — Catalogue-

making is often a thankless task, but skillfully and conscientiously

done, the results are of the utmost importance in all systematic work

in biology. American entomology has been especially fortunate in

its cataloguers of the two-winged insects. The last is Professor

J. M. Aldrich, who has just produced a voluminous work of 680

Pages, containing full lists and bibliographies of all known American

Species of Diptera north of South America. The work has been a

stupendous one, involving most of the author's available time for the

past eight years. It is, however, far more than a mere bibliograph-

ical catalogue of genera and species, since it contains many critical

notes on the distribution and validity of the forms catalogued. One

Is surprised at the amount of work that has been accomplished in the

order since the Appearance of Baron Osten-Sacken's Catalogue in

1878. 'The number of known species has been nearly doubled,

Increase in the genera has been even greater, there being 1230 recog-

nized as valid in Professor Aldrich's catalogue.

€ beginning of a new epoch in the

study of these insects, The writer has examined the catalogue very

lAldrich, J. M. A Catalogue of North American Diptera (or Two-winged

flies). Smithsonian Misc. Coll., vol. 46, 680 PP-; 1905.

No. 466] ` NOTES AND LITERATURE. 753

carefully, and is surprised at the remarkably small number of errors

it contains, whether of omission or of commission. Notall will agree

with the author in some of his views as expressed in his arrange-

ments and distribution, though they seem for the most part well

founded. But that matters little; the information is all there, and

one does not have to follow the author if he has good reasons for

not doing so.

S. W. W.

Barron's Old Whaling Days.'— This interesting narrative may

be classed with Bullen’s Cruise of the Cachalot as a whaling epic,

written by one who started as a cabin boy and eventually became

master. Bullen gave us an account of the capture of sperm whales

in temperate and tropical seas; Captain Barron takes us to the arctic

regions in pursuit of the Greenland right whales that follow close

along the edge of the ever-changing ice pack.

Sailing first in 1849, Barron made seventeen voyages to the arctic

waters, chiefly west of Greenland, in pursuit of seals and whales and

gives a graphic account of the many dangers encountered in the sud-

den shiftings of the ice, the frequent gales and storms, and the bitter

cold. About 1851, ships’ crews commenced the practice of winter-

ing in the Cumberland Sound region that they might pursue the

whales with the first return of the sun after the long arctic night.

The introduction of steam whalers in the late 50's did away with

many of the hardships that sailing vessels imposed upon their crews.

For many years, Hull, England, was the chief clearing port for the

arctic whalers, but by 1869 the trade was abandoned there.

Although the author does not pretend to any scientific knowledge,

he tells a number of interesting facts in regard to the habits of

whales and other animals. It is stated that one right whale, on

being struck, sounded at once and in 34 minutes ran out 3600 feet

of line indicating a speed of about 1000 feet a minute, which must

be unusual for this species. The whale was then hauled up dead,

having struck the sea bottom with such force as to break its neck.

Barron also makes the interesting observation that thousands of

young harp seals are sometimes killed in gales by the floe ice break-

ing and driving over them.

The main value of this book is in preserving a record of the

perils and hardships suffered by the hardy whalers of a past genera-

1 Barron, William. Old Whaling Days. William Andrews & Co., Hull; A.

Brown & Sons, London, [1905]. 12mo, x + 211 pp. 3/6. :

754 THE AMERICAN NATURALIST. (VoL. XXXIX.

tion, their methods of work, their losses or successes, in a calling

now almost past. “When the trade was at its height, there were

occasionally fair fortunes made, and the crews at times were well

paid. The life was frequently one of great privation, and at times

of deep denial and not a little danger. There was, however, much

of fascination in the pursuit of seals, whales, and other creatures of

the far north, and one cannot help a feeling of regret that these

days have passed away never to return.”

G. M. A.

Notes.— In a paper by Miss M. J. Klem, entitled “ A Revision of

the Palzozoic Palaéchinoidea, with a Synopsis of All Known Species”

(Trans. St. Louis Acad. Sci., vol. 14, no. 1, May 5, 1904) there are

a number of conclusions drawn to which attention should be called.

These are mainly apparent refutations of the principles of develop-

ment given by Dr. R. T. Jackson and Dr. T. A. Jaggar in their

paper on “Studies of Melonites multiporus” and by Dr. Jackson in

his paper “Studies of Palzéchinoidea ” (Bull. Geol. Soc. Amer.,

vol. 7). These apparent refutations seem to arise from a miscon-

ception of the principles of development as given in those papers.

On page 2 of Miss Klem’s paper the statement of the above au-

thors that “the interambulacral area of the adult of Melonites when

perfect, consists of two plates at the ventral termination ” is claimed

to be incorrect and. she maintains that it always terminates in three

plates when the specimen is perfect, citing figures 6, 8, 12, and 13 in

proof. In these sixteen drawings in which the line marking the ven-

tral border of the perfect specimen is shown but four times (in 64,

6d, 12¢, 13¢) the completion of the adambulacral plates laterally to

show the impingement of the ambulacral plates is lacking, a feature

which would give much more definiteness to the whole series of

figures. In these sixteen drawings all of which are claimed to show

the invariable termination in three plates, four areas show termina-

tion ventrally in two plates (figs. 6a, 62, 6c, 8c). This substantiates

the point in question, that when perfect the area terminates in two

plates as shown by Jackson and Jaggar. The other figures repre-

sent cases in which there are three or more plates ventrally which

according to Jackson and Jaggar are wanting in the plates found at

the ventral part of a complete specimen. On page 3 is a statement

of doubt concernin

trally.

power of resorption perfectly clear.

A SE

t the end of the page is this statement: ‘Furthermore, if resorp-

No. 466.] NOTES AND LITERATURE. 755

tion took place (which I doubt very much) by what law of nature

could the plates twist themselves from the position indicated in fig.

11, pl. 3, to that shown in fig. ro, pl. 3?" A more careful reading

of their explanation of the figures would show that tbe plates would

not by any law of nature necessarily have to twist themselves in any

way, as it is stated that figure 11 is adapted from one specimen,

while figure 10 is drawn from an entirely different specimen which

is described as aberrant.

In regard to the idea of the introduction of columns there is an

entire misunderstanding of the statements of Jackson and Jaggar.

They call the two columns which terminate at the ventral border,

columns ı and 2, then the next added column is spoken of as the

third column, etc. Miss Klem does not make this grouping but

makes one of her own, in which the early columns are ignored and

the first column in her scheme is the first one added above the bor-

der shown in her figures. "Therefore the first column of her scheme

may correspond to the third, sixth, or any column of the other au-

thors except what they really call the first. With such a failure to

use equivalent terms it is obvious that other results are obtained

especially in a group where the structure is largely one of numerical

sequence. As a result of this difference in terminology, the follow-

ing statement is made: “While this rule (‘that.... newly added

columns normally alternate to left and right as introduced, even

numbered columns typically appearing on the right of odd ones’)

may apply to some isolated and imperfect. specimens, the contrary

becomes quite evident by examining a large and complete collection

of perfect fossils." Twenty-three figures are referred to in order to

show that the rule does not hold in usual cases. However, by using

the basis of numbering given by the original authors at least seven-

teen out of these twenty-three figures given by her show decidedly

the correctness of their rule.

A statement which needs correction is given on page 5: “An-

other feature, which will not stand a critical test, is the supposition

of the above mentioned authors, that new columns are always intro-

duced by a pentagonal plate with the apex pointing ventrally or

toward the oral area." Exceptions are given to the rule but the fact

is overlooked that the original authors show that there are excep-

tions, as in figure ro where a column is introduced by a tetragonal

plate, in figure 14 where one is introduced by a hexagonal plate, and

in figure 16, where one is introduced by a heptagonal plate, the same

variations that Miss Klem simply reiterates. The statement is made

that “the initial plate of a column when pentagonal often has the

756 THE AMERICAN NATURALIST. [Vor. XXXIX.

apex pointing dorsally," but there are no examples of its frequence

given and in looking through the figures carefully but two cases in

over a hundred show the apical angle in a position which may be

considered as pointing dorsally in relation to the axis of the newly

added column.

On the whole Miss Klem's paper instead of in any way disproving

the views originally worked out by Jackson and Jaggär seems, in so

far as it goes, to be a confirmation of them when they are reduced

to equivalent terms.

The bibliography includes works that have only a bare mention of

the Echini, as Zittel's Geschichte der Geologie und Pal«ontologie,

while certain others are left out, the most prominent noted being

Alexander Agassiz's “Revision of the Echini.”

In the systematic treatment there are a number of statements

which are open to criticism. On page ı is the statement that “all

the Palzozoic Echini belong to the C/uss Cidaride” (italics are mine).

On page ro the class is given as Echinoidea. Also on the same

page is given a list of the prevailing characters on which the classifi-

cation is based. In these the number of columns in the interambu-

lacrum is left out but is nevertheless used in all the descriptions.

The number of columns in the ambulacral areas and the number of

pores are considered as two of the most important characters. This

latter portion is due possibly to the surprising statement made that

Palzechinus has four pores in each ambulacral plate. As given in

the generic description Palzechinus has but two columns of ambu-

lacral plates, but under P. /acazei Julien (page 34), primary and

secondary plates are spoken of and one pair of pores is given with a

question. Such a condition is in line with the accepted idea that all

the Palaeozoic Echini have a single pair of pores to each ambulacral

plate.

Frequently the generic description does not.agree with the char-

acters given under the various species. For example, Lepidesthes

is stated to have ten columns of plates in each ambulacral area.

Five species are given, the first with 18 to 20, the second with 10 or

12, the third with 8 or 9, the fourth with 10, the fifth with aa A

summary would give 7 to 20 instead of ro. In Lepidechinus the

number of interambulacral plates is given as 9 to 11. But two

species are given, the first with 8, the second with 7 to 9 columns of

plates in this area. Many other instances might be pointed out but

these suffice to show that the statements given in this work should

be carefully confirmed before being accepted.

J. A. CUSHMAN.

No. 466.] NOTES AND LITERATURE. 757

The mechanism by which geckos and other lizards cling to smooth

overhanging surfaces has been investigated by Schmidt (Jena. Zeit-

schr., vol. 39, pp. 551-580), who finds that the scales on the under

sides of the toes of these animals carry clusters of fine hair-like bodies

which, however, end in small flat faces and not in points. The under

surfaces of the toes are provided with blood spaces that act as

erectile organs and the whole mechanism gives no support to the

idea that these animals adhere to overhanging surfaces by suction.

Schmidt believes that the act of holding on to the surface is depen-

dent upon the hair-like bodies and he is inclined to ascribe it to some

electrical phenomenon produced by them.

The comparative anatomy of the Fallopian tubes in mammals has

been fully worked out by U. Gerhardt (Jena. Zeitschr., vol. 39, pp.

649-712).

The mutual relations of the kidneys and gonads in Haliotis have

been studied by Totzauer (Jena. Zeitschr., vol. 39, pp. 527-550).

The two kidneys are not in communication with each other, but open

separately into the mantle cavity. The rudimentary left kidney com-

municates with the pericardium and opens into the mantle cavity on

the left side of the rectum directly. The right kidney has a well

developed duct leading to the mantle cavity and also an opening into

the pericardium. The gonads are discharged through their own ducts

into the right kidney from which their products escape into the man-

tle chamber through the duct of the right kidney.

Boveri (Jena. Zeitschr., vol. 39, PP- 445-524) in a series of experi-

ments on sea-urchin eggs, has shown that abnormal numbers of

chromosomes in eggs or in blastomeres are inherited unchanged by

the descendant cells. Cells with abnormally large numbers of chro-

mosomes are abnormally large and have abnormally large nuclei and

the reverse. The number of cells in a growing sea-urchin larva is

inversely proportional to the chromatin content thus showing a rela-

tion between the amount of chromatin and tbe amount of proto-

plasm. This relation, which is in the form of a regulation, is

established through the number of cell divisions which the cytoplasm

of the egg may undergo.

E. P. Felt's Report on the mosquitoes or Culicidz of New York

State (New York State Museum, Bull. 79, 168 pp. 57 pls.) * repre-

sents about three years’ work and gives a comprehensive account of

the mosquitoes occurring in New York State, with special reference

758 THE AMERICAN NATURALIST. (VoL. XXXIX.

to methods of control. Some 55 species are treated, the larva or

wrigglers of 43 are described, and accounts of their habits and life

history are given. There are tables for the separation of adults and

larvee, and the value of the work is greatly enhanced by over 100 origi-

nalline-drawings and 57 excellent process plates reproduced from

the author's photomicrographs. The keys and illustrations should

enable physicians, and in fact almost any person having a fair micro-

Scope at his disposal, to identify most of the common forms in either

the adult or the larval stage. This bulletin should also appeal to

teachers interested in nature study, since no group of insects lends

itself more readily to class room conditions."

In a sumptuously illustrated article on the Rocky Mountain Goat,

Mr. Madison Grant (Ninth Ann. Rept. N. Y. Zool. Soc., pp. 1-36)

gives an account of the characters, relationships, distribution, and

habits of this peculiar group of animals. A number of photographs

of living and mounted specimens illustrate the paper.

A list of the mammals of North Carolina, exclusive of the Cetacea,

by C. S. Brimley (Journ. Elisha Mitchell Sci. Soc., 1905) records 66

species at present known from the State. Short notes on the distri-

bution and analytical keys for determination of the species, make it

of general value to others than specialists.

ANTHROPOLOGY.

La sociologie génétique ! — genetic sociology — occupies itself,

according to the definition of the author (p. 3) with *the origin of

human society and all the phenomena by which it is influenced ; the

term being equivalent with social embryogeny.” - :

The writer endeavors in one small volume to give an outline of the

sources and development of the essential constituents of human

organization, and he is not entirely successful. He has produced a

work of generalities and philosophy, on facts that are not always

ample enough, or fully reliable.

The material utilized consists of (1) studies of animal societies

and animal life; (2) studies of savage. peoples; (3) results of

1 Cosentini, Francois. Za sociologie génétique; Essai sur la pensée et la vie

sociale préhistoriques. Intröduction de Maxime Kovalewsky. Bibliotheque de

Philosophie Contemporaine, Paris, Alcan, 1905. 8vo, xviii -++ 205 pp.

No. 466.] NOTES AND LITERATURE. 759

palethnology and paleontology; (4) historical data concerning the

progress, during long periods, of a single society; (5) ancient

written laws and customs; (6) myths, popular traditions, archeologic

monuments; (7) psychologic induction ; and (8) survivals of cul-

ture of primitive age. In nearly all these lines the author apparently

labors under the serious disadvantage of relying upon documentary

evidence alone, lacking a thorough, personal, practical acquaintance

with the subject, which is essential, even in the presence of good

documents, to true reasoning and conclusions.

The seventeen chapters of the book treat, respectively, of the

object, róle and sources of genetic sociology; animal societies ;

modern savages; human races and polygenism ; palethnologic data ;

primitive man; primitive family; primitive society; primitive pro-

priety (possessions); primitive ideas; mythologic conceptions; lan-

guage and writing; religion ; morals; laws; politic organization and

social classes; and art, industry and commerce. ‘The author is at

his best in the divisions on animism (* primitive ideas”) and religion ;

the exposition of these subjects is concise and clear, and the ground

is better covered than elsewhere.

The writer adheres to the polygenic theory of human evolution,

and the matriarchal theory of the primitive family; he opposes the

idea of society being derived from the family. The humble com-

mencements of human society must be sought with man's immediate

precursors. The actual societies of savages offer much analogy

with that of primitive (early) man. Individual possessions followed

"propriety in common, and, beginning with a few personal effects,

developed particularly with the domestication of animals. e

cosmic ideas of the primitive man were those of animism. Lan-

guage was preceded by mimicry and its beginnings were imitations of

animal sounds; the first words consisted of imitative sounds and of

gestures; the first stage of language was monosyllabism. Religion is

based upon animism, which constitutes the minimum of religiosity.

Morals are developed independently of religion. Laws are but

moral rules, admitted and sanctioned by groups of humanity. In

politic organization the clan preceded the tribe, which latter was

formed by an enlargement of one or a coalition of several clans.

The first class in society was the military, which later on constituted

fhe aristocracy; the next class was the sacerdotal, the third the

plebeian, etc. The various grades of the civil society, manifested at

the present in space, are living documents of successive transforma-

tions accomplished in time.

760 THE AMERICAN NATURALIST. ` (VoL. XXXIX.

In several places in his book M. Cosentini adduces, as a testi-

‘mony, the status of the * peau-rouges" or Indians. The term “red-

skins" should once for all be abandoned. The skin of the Indian is

of a yellowish brown toa pure brown, much like that of the Malay, and

not red. And when the Indians are quoted it should be only with a

good ethnological acquaintance with them, and not as a people of one

homogeneous culture. They, or at least the great majority of them,

must not be classed with the Bushmen and other world's lowest

savages. Nor do the Esquimaux deserve such a classing.

There are numerous other points in the book which demand, if not

an objection, at least an argument. The space does not permit to

mention but two. On page 64 the principal directive motives of the

conduct of the primitive man are given as egoism — force — robbery

— cruelty — cannibalism ; what substantiation can the author bring

forth for this singular conception of our ancestors? The second

point concerns a notion closely allied, if not tbe result, of the preced-

ing. It relates to the criminals. Criminals are, for the writer,

" from anthropological and psychical view, a return to inferior race "

(Pp. 32) ; and again (p. 193), “crime is a hereditary (atavistic?) return

to a former degree of development of our race, to the epoch when no

crime has yet existed." This makes a primitive instead of a defective

man out of the criminal!

ACE.

« Notes.— Distribution of Blondes and Brunettes in Holland.— In

order to obtain some definite data on the distribution of the dark

and light types of population in Holland, Dr. Bolk addressed numer-

ous teachers and with their aid secured data on nearly 500,000

children. These data (Ju. Soc. d’ Anthropol., ser. 5, V0l. 5, p. 575.

1904) show that the dark type is rare in the northern provinces, not

exceeding, in many localities, more than ten percent of the popula-

tion ; and that it increases southward, reaching the maximum (40

percent and over) in the provinces of Zeeland, Noord- Brabant, and

Limburg. This dark type corresponds, in the opinion of the author,

to the brachycephalic “ Alpine” type. Among the blondes are

recognizable two distinct physical varieties: one, with a longer head

and face, best represented in Friesland and corresponding to the

Nordic" or Germanic race; the other, brachycephalic and with a

shorter face, found principally in the province of Drenthe, and rep-

resenting the so called Oriental race of whites. It would be very

Interesting to have these results supplemented by similar data on

Belgium.

No. 466.] . NOTES AND LITERATURE. 761

Skulls and Skeletons from the Santa Rosa Island, California.—

Prof. Matiegka describes (Sitzungsber. k. böhm. Gesellsch. d. Wis-

sensch., 1904, p. 1) in a thorough manner, fifteen crania and four

more or less complete skeletons from the Santa Rosa Island. With-

out going into details it is sufficient to say that the characteristics of

the skulls here described agree closely with those of the skulls from

the same and neighboring islands, described by previous observers.

'The majority of the skulls are mesocephalic and with a length-height

index ranging principally between 7o and 74. Asto the bones of

the skeleton, Matiegka's description is the first of its nature from

California. The description contains many interesting points for

which the reader must be referred to the original. The pelvis is

closely related to the European. The radio-humeral index is nearly

79; the tibial-femoral index, 83.5 ; the relation between the upper

and lower limbs, 70.5 (in males).

Cephalic Index in Switzerland.— This communication (Bull. Soc.

d Anthropol., ser. 5, vol. 5, P- 493» 1904) is a brief, interesting report

on the form of the head in 587 children, from ro to 14 years of age,

in the Canton of Vaud. The mean cephalic index of the entire series

of children was 82.02, corresponding to the index of about 80.02 on

the skull. Previous observations by different authors in other cantons

gave indexes from 80.6 (Geneva) to 85 (Grisons) and even 87 (a part

of Valais), showing that the Swiss population is predominantly sub-

brachy- and brachycephalic.

Portuguese Cranial Capacity and Ethnic Composition. — The

author (Bull. Soc. d Anthropol., ser. 5, vol. 5, p. 473, 1904) utilizes

the measurements obtained by Macedo, Marques, Basto, and Cardoso,

and by their aid, but principally by the data on cranial capacity,

attempts to differentiate the Portuguese into several types of people

of different origin. According to Macedo's measurements the mean

height of the Portuguese in general is, in men, 164.1 cm, mean

cephalic index (on skull) 74-5; and mean capacity of the skull (by

Broca's method?) 1572 c. c. The main differences are found in the

following districts :—

Cephalic Index Nasal Index

Stature. (Skull). (Living). ^ Cranial Capacity.

Traz-os-Montes (north) 163-3 72.5 66.9 1507 C. C

Beira Alta (north) 167-4 72.5 5. 1596

Alemtejo (south) 166.2 74.8 64.6 1547 :

Minho (north) 165.8 75-7 64.2 1591

Ferreira concludes, on the basis of such differences (but not with-

762 THE AMERICAN NATURALIST. (VoL. XXXIX.

out taking account of some historic data of invasions), that there

exist among the Portuguese two dolichocephalic and three mesati-

cephalic types of people. "Traz-os- Montes population represents one

of the dolichocephalic types and that of Beira Alta the other. The

population"of Minho has been modified by Celtic invasion.

The whole article leaves much to be desired, if not criticised.

The data are not always ample enough, even if admitted as homo-

geneous. The conclusions, and there are many besides those

mentioned above, lack a much needed, more-sided, individual corro-

boration. Nor is the wording always careful enough; the definite

term brachycephaly is employed loosely, and so is, to a certain

extent, that of mesorhyny.

A. H.

BOTANY.

Leaves of English Forest Trees! .— This volume forms the

second in the author's series of works on forest trees. It is devoted

to an extended treatment of the leaf from several standpoints.

Part 1 of the book is general and concerns itself with the anatomy,

morphology, and physiology of the leaf in an elementary way. The

subjects of phyllotaxy and venation are given a brief, but lucid

treatment. The relation of different forms of leaves to each other is

explained by the aid of a few simple mathematical figures. The cell

structure of the leaf is treated in a very popular, almost superficial

manner. Part of this treatment is very good, but the author

endeavors to make it plain by the introduction of dangerously broad

analogies. n

In describing the physiology of the leaf, the author carries his

similies beyond all bounds of necessity or reason. In explaining

the processes of metabolism, he attempts to make them realistic by

describing the grotesque experiences of an imaginary “traveller ” in

the tissue of the leaf. After reading the adventures of this traveller

during the night, we have the following vivid account of his experi-

ences during the time of day when photosynthesis is going on

(p. 92): “In addition to the bombardments of the rushing molecules,

our traveller in the Passages would also probably perceive violent

1 Ward, H. Marshall,

and the Laboratory.

348 pp., illustrated,

Trees. A Handbook of Forest-Botany for the Woodlands

ol. II. Leaves. Cambridge University Press, 1904. 12m0,

No. 466.] NOTES AND LITERATURE. 763

explosions in the cells as molecule after molecule of carbon-dioxide

was torn asunder by the chlorophyll machinery, and would feel or

see the walls of the cells heaving in huge oscillations as the moving

protoplasmic contents and cell-sap surged under the stress of the

chemical forces at work, or of the physical displacements due to the

rupture of the molecules and the clashing together of atoms in the

course of reconstruction into new groupings.”

It is extremely doubtful if the student of forestry, for whom this

book is intended, will be helped by such fanciful or roundabout

descriptions of important phenomena. If forestry is to be taken

seriously, there is no reason why the actual facts should be dressed

in such grotesque language. In many ways, however, the discussion

is unusually good. The chief error is an apparent ene’ to

simplify the subject.

Part 2 of the book is special and is devoted to an analytical key of

English forest trees based entirely on the character of the leaves.

The descriptions are written with admirable completeness and are

unmistakably plain. Although such an analysis throws strangely

unlike things together, there is no reason why it should not prove

very useful.

The book is one for the amateur student of forestry, but will only

be of incidental value to the scientific student.

H. S. R.

Finer Structure of Commercial Timbers.— The object of this

book is to enable one to identify commercial woods without the

bark, leaves, flowers, or fruit of the tree. The author describes two

hundred and forty-seven of the principal commercial timbers of the

world. While the descriptions are primarily intended for trade pur-

poses, they will also be of value to the student of microscopic

anatomy.

. The timbers of trees are arranged in genera. and families accord-

ing to the system of Bentham and Hooker. The following charac-

ters are noted for each wood : common names ; sources of supply;

physical characters (weight per cubic foot, hardness, smell, taste,

alcoholic and aqueous solutions, inflammability) ; grain ; bark ; uses;

color ; anatomical characters (pores, rays, rings, pith, etc., in trans-

verse, radial, and longitudinal sections) ; location of type specimens ;

and authorities.

. 1Stone, Herbert. “The Timbers of Commerce and their Identification. London,

Wm. Rider & Son, 1904. 8vo, 311 + xxxviii pp. illustrated with 186 photo-

MPEG E by Arthur Deane.

: 764 THE AMERICAN NATURALIST. [Vor. XXXIX.

The introduction to the book gives a somewhat technical discussion

of the botanical nature of wood and a description of the way in which

different woods are formed by growth. Under the title “ Practical

Hints," directions are given enabling one not skilled with a micro-

scope to identify woods by their structural characters. It also tells

how to make and mount thin sections of wood for examination with

the microscope or with the stereopticon.

The descriptions are illustrated by one hundred and eighty-six

excellently reproduced photomicrographs. The scale of magnifica-

tion is three times the natural size and is designed to show the

appearance of the transverse section as seen by means of an ordinary

hand lens.

A good bibliography and index enhance the value of the book.

A Notebook for the Botanical Laboratory in the High School.

— The author has prepared this notebook with special reference to

the work outlined in his well known text-books. The book gives

comprehensive directions to the pupil for setting up experiments. It

contains convenient ruled and blank sheets for the record of results,

and there is also ample space for making drawings. It will do much

to save time and trouble by minimizing the amount of routine dicta-

tion demanded from the teacher. The notebook will help to develop

accuracy, self-reliance, and originality in the pupil. It teaches him

to be systematic without confusing him with a mass of unnecessary

directions.

HSR

Notes.— A paper on fungous diseases of the cranberry, by Shear,

forms Farmers’ Bulletin no. 227, of the U. S. Department of Agricul-

ture.

A popular abridgment of Lovell’s papers on colors of flowers is to

be found in The American Botanist, for March.

An account of the shade trees of Denver forms Bulletin 96 of the

Experiment Station of the Agricultural College of Colorado.

The roots of plants serve as subject for Bulletin no. 127 of the

Experiment Station of the Kansas State Agricultural College, by

Ten Eyck

Bergen, J. Y. A Notebook to Accompany Bergen’s Text-books of Botany.

Boston, Ginn & Co., 1904. 4to, 144 pp. .

No. 466.] NOTES AND LITERATURE. 765

A paper by Chauveaud on the secretory apparatus of Taxus is

published in no. 7 of the Bulletin du Museum d’ Histoire Naturelle

of Paris for 1904.

Papers on the bamboos are being published by Bureau in current

numbers of the Bulletin du Muséum a’ Histoire Naturelle, of Paris.

Botanically interesting studies of the sand-drift problem in New

South Wales are contributed by Maiden and McMaster to vol. 37 of

the Journal and Proceedings of the Royal Society of New South Wales,

recently issued.

An account of aluminum as an important element in certain trees

is published by H. G. Smith in vol. 37 of the Journal and Pro-

ceedings of the Royal Society of New South Wales.

The Journals. — Torreya, April: — Harper, * Some Noteworthy

Stations for Pinus palustris" ; Murrill, * Terms applied to the Sur-

face and Surface Appendages of Fungi”; King, “ Experiment to

show that the Absence of Light alone will Prevent the Process of

Photosynthesis ”; Parish, “ Birds and Mistletoe — a Correction” ;

Cockerell, * The Name Melampodium."

The Plant World, March : — Nash, “A Trip to the Inaguas”

Arthur, “On the Nomenclature of Fungi having Many Fruit

Forms”; Streeter, ^A Treasure Spot of Wild Flowers"; Wiegand,

“The Biology of Buds and Twigs in Winter.”

The Ohio Naturalist, April:— Claasen, “Key to the Liverworts

recognized in the Sixth Edition of Gray's Manual of Botany";

- Smith, “Key to the Ohio Elms in the Winter Condition"; Gleason,

“Notes from the Ohio State Herbarium — III ": Riddle, “ Devel-

opment of the Embryo Sac and Embryo of Staphylea trifoliata."

GEOLOGY.

Merrill's A Treatise on Rocks, Rock-weathering, and Soils.'—

This work, which appeared in 1897, was reprinted from electrotype

plates in 1904, with an inserted list of errata which apparently the

method of reprinting precluded embodying in the text. This work

1 Merrill, George P. A Treatise on Rocks, Rock-weathering, and Soils. New

York, The Macmillan Co., 1904. 8vo, xx + 411 PP-, 25 pls., 42 text figs. $4.00.

766 THE AMERICAN NATURALIST. [Vor. XXXIX.

is especially intended to elucidate the formation of soils and surface

deposits and as such holds a unique place in special texts for the

instruction of students in agriculture and forestry. The chapters on

the igneous rocks surpass those in most text-books of geology for the

general student; and in the field covered by the book the author has

done a notable service in informing the general student concerning

the important surface changes involved in the weathering of rocks.

The work is now so well known to students and teachers of geology

that it does not seem necessary to call further attention to the subject-

matter of the reprint. It isto be regretted that so important a work

should retain so many typographical errors. For this defect the

electrotype process, the special character of the treatise, and the

probable limited sale of the work, must be held responsible at this

time.

jc: B We

Notes.— “ The Geology of the Hudson Valley between the Hoosic

and the Kinderhook,” by J. Nelson Dale, has appeared as Bulletin

242, of the United States Geological Survey. This paper serves as

a supplement to the work previously published as Monograph 23

(1894), and gives a series of maps and cross sections from the west-

ern Hoosic River to the longitude of Albany. . "T

Bulletin 238 of the United States Geological Survey is by Adams,

Haworth, and Crane, and has for a title “ The Economic Geology of

the Iola Quadrangle, Kansas." Nearly three quarters of the report

deals with the oil and gas production of this region. The oil and

gas are derived. mainly from the Cherokee shale, which is the lowest

member of the Pennsylvanian, or Lower Carboniferous, series. The

character and distribution of the Kansas oil seems-to point-clearly to

an organic origin. ; xs kant

C. W. Wright, after a short visit to Alaska, has extended the

knowledge of the placer fields by a description of “ The Porcupine

Placer District, Alaska ” (Bulletin 236, United States Geological Sur-

vey). In this paper, Mr. Wright points out that the gold found in

the placers is mainly derived from local sources, namely, a series of

» M: publication is to afford topographers, both in the field and in

e ofice, a Convenient compendium of necessary tables and formulas:

No. 466.]:..: ‘WOTES‘AND. LITERATURE. 767

F. G. Plummer and M. G. Gowsell contribute an account of “ The

Forest Conditions in the Lincoln Forest Reserve, New Mexico."

This paper appears as Professional Paper 33 of the United States

Geological Survey. The maps and illustrations are particularly

interesting to the general reader.

An interesting feature brought out by the map accompanying the

report on “ The Forest Conditions in the Little Belt Forest Reserve,

Montana, and the Little Belt Mountains Quadrangle,” by J. B.

Leiberg (Professional Paper 30, United States Geological Survey), is

the large amount of territory that has been deforested by fire. It is

estimated that of the 500,000 acres in the reservation 111,000 acres

have had the forests destroyed by fire.

Bulletin 258 of the United. States Geological Survey is a second edi-

tion of *Origin of Certain Place Names in the United States," by

Henry Gannett. It contains all the notes of the earlier edition (Bu/-

letin 197, United States Geological Survey) as well as some fifty-four

additional pages. .

FR A. Wilder, in “The Lignite of North Dakota and its Relation

to Irrigation” (Water Supply and Irrigation Paper, 117), presents

much interesting matter concerning this fuel. The lignite area, save

for two or three outliers, occupies the western portion of the State.

In this area, which is nearly half the size of Ohio, there are seams of

lignite from an inch up to forty feet in thickness.

Water Supply and Irrigation Paper, 114, “The Underground

Waters of Eastern United States," presents a general summary of

the 'ground-water conditions east of the Mississippi River. The

waters of each State are treated, either by the State Geologist or by

some member of the United States Geological Survey who has made

special investigations in the area. Appended to the description of

each State 1 is a brief bibliography of the more important papers.

Bulletin 3, Fourth Series, Geological Survey of Ohio, is a volume

of 391 pages and 81 Pentre by A. V. Blaininger on the “ Manufacture

of Hydraulic Cements.” The chapters on “The Analysis and Test-

ing of Raw Materials” and “The Burning of Portland Cements ”

should be especially useful to a due cement manufacturers and

cement chemists.

768 THE AMERICAN NATURALIST. [Vor. XXXIX.

The work accomplished by the United States Geological Survey

for the year 1903-1904 is summarized in the 7wenty-fifth Annual

Report of the Director of the United States Geological Survey to the

Secretary of the Interior, published in Washington, 1904. The vol-

ume consists of 388 pages, 25 plates, and 2 figures.

A novel way in which vegetation may leave evidence of its exist-

ence is described by C. H. White, with illustrations, in-the American

Journal of Science (vol. 19, March, 1905, pp. 231-236). This process

consists in the abstraction of coloring matter of the rock on which

the plant grows, or the precipitation of coloring matter by the plant.

The result of either process is to produce a picture of the plant

by the plant itself. For such a picture White proposes the term

" autophytograph," and for the process * autophytography."

Professional Paper 31, of the United States Geological Survey, is a

" Preliminary Report on the Geology of the Arbuckle and Wichita

Mountains in Indian Territory and Oklahoma” by J. A. Taft, with

“An Appendix on Reported Ore Deposits of the Wichita Mountains ”

by H. F. Bain. This report, of 97 pages, is well illustrated by 8

plates and 1 figure.

“The Preliminary Report of the Ohio Cooperative Topographical

Survey, Nov. 15, 1903,” published in Springfield, Ohio, in 1904,

gives in its 227 pages a description of the methods employed, and

carefully tabulated elevations and positions for the points located by

the Survey.

“The Uses of Hydraulic Cement,” by F. H. Eno, appears as

Bulletin 2, Fourth Series, Geological Survey of Ohio. The account

is quite popular in style, and the subject matter is of more interest

to the constructing engineer than to the geologist. The report treats

of hydraulic cements in general, rather than those of Ohio in partic-

ular. The following chapter headings suggest the scope of the

work: A Brief History of Cement, Uses of Cement in Mortars, Uses

of Cement in Concrete, Uses of Cement in Reénforced Concrete,

Specification for Concrete Materials, Materials and Tools. :

W. M. Davis, in an article on

Suess’ Theories ”

adversely criticise

“ The Bearing of Physiography upon

(Amer. Jour. Sci., 4th series, vol. 19, pp. 265-273)

S the idea that certain plateau-like masses, such as

the Schiefergebirge, owe their altitude, not to their own uplift, but to

the subsidence of the surrounding lower areas.

No. 466.] NOTES AND LITERATURE. 769

C. Davison on “Earthquakes in Mining Districts” (Geol. Mag.,

no. 491, May, 1905, pp. 219-223) describes three shocks apparently

due to the removal of coal or the pumping out of water, which

resulted in underground slips along fault planes.

The great Cullinan diamond is described and illustrated by Hatch

and Costorphine in the Geological Magazine (no. 490, decade s, vol.

II, pp. 170—171, 1905) in an article entitled * Big Diamond from the

Transvaal."

A summary of the laws of the various states regarding underground

waters has been prepared by Dr. D. W. Johnson, and published as

Water Supply and Irrigation Paper, 122, of the United States Geo-

logical Survey, under the title “Relation of the Law to Under-

ground Water."

The pollution of the water of Lake Champlain by the discharge of

waste from pulp mills and sewage has been studied by M. O

Leighton of the United States Geological Survey, and the results of

this investigation are published as Water Supply and Irrigation

Paper, 121 —“ A Preliminary Report on the Pollution of Lake

Champlain."

A valuable bibliography of 628 titles of the different papers on

underground water published by the United States Geological Survey

during the past twenty-six years, with brief notes on each paper, has

been prepared by M. L. Fuller, and published as Water Supply and

Arrigation Paper, 120. |

A valuable paper, entitled “Preliminary Report on the Under-

ground Waters of Washington," has been prepared by the State

Geologist, Henry Landes, and published by the United States Geo-

logical Survey as Water Supply and Irrigation Paper, 111.

An interesting group of fourteen papers has been collected under

the title of “Report on Progress of Investigations of Mineral

Resources of Alaska in 1904.” This appears as Bulletin 259 of the

United States Geological Survey, Washington, 1905. The placer

deposits are especially well treated.

A continuation of Professor Russell’s previous work on the varied

and interesting features of the geology of Oregon has recently

appeared as Bulletin 252 ofthe United States Geological Survey,

entitled “ Preliminary Report on the Geology and Water Resources

of Central Oregon,” Washington, 1905.

770 THE AMERICAN NATURALIST. [VoL. XXXIX.

The report of G. C. Martin on “The Petroleum Fields of the

Pacific Coast of Alaska,” (Bulletin 250, United States Geological

Survey) shows that the oil is of high grade and of considerable eco-

nomic promise. It is evident that the oil, which is derived mainly

from the Mesozoic strata, contains a high percentage of volatile

compounds, has a paraffin, base, and a low sulphur content. From

analyses made of surface seepage samples, the oil seems to be very

similar to that from Pennsylvania.

PUBLICATIONS RECEIVED.

(Regular exchanges are not N

BARRON, CAPTAIN WILLIAM. Old Whaling Days. London, A. e &

Sons, Ltd., 1905. 12mo, x-+- 211 pp.— DUCKWORTH, W. Morphology

and Anthropology. A Handbook for Students. Gumbriäge Biological: Series,

Lo sep Macmillan & Co., 1904. 8vo, xxvii + 564 pp., 332 figs.— GARDINER,

J. S., ED. The Fauna and Geography of the Maldive and Laccadive Archi-

Mic etc., vol. 2, pt. 4, pp. vl a pls. d text figs. 127-129. Cam-

bridge, Engl., Univ. Pri: den 0.— GARDINER, J. S., ED. The Fauna and

Geography of the Maldive and lace Anke etc., vol. 2, suppl. ı

PP- 923-1040, pls. 88-C, text figs. "o Cambridge, Engl., Univ. Preshi

1905, 4to.— HARMER, S. F., HERDMAN, W. A., BRIDGE, T. W., AND BOULEN-

GER, G. A. The Cumblidge Natural nn Vol. 7. Hemichordates, Asci-

dians, and Amphioxus, Fishes. Lon . Macmillan & Co., 1904. 8vo, xvii +

760 pp. 440 figs. — MCMURRICH, J. Pak The Development of the

Human Body. A Manual of Human Embryology. P. Blakiston's Son & Co.

Philadelphia, 1904. 8vo, 2d ed., i-xix, 17- 539 PP-, 272 text figs.— OVERTON, F,

AND HILL, M. E... Nature Study. A Pupil’s Text-book. New York, Cincinnati,

Chicago; A Book Co., 1905. 12mo, 142 pp., illus.— PECKHAM, G.

AND E. G. Wasps Social iid Solitary. Boston and New York, imghitost,

Mifflin and Co. . 1905. 12mo, xv + 311 pp., illus.— SEDGWICK, ADAM. A Stu-

ents’ Text-book of Zoölogy, vol. 2. London, Swan Sonnenschein & Co.

- L. Catalogus Mammalium tam Viventium quam Fossilium. Quinquennale

BWleuinris; Anno 1904. Berlin, R. Friedländer & Sohn, 1905. Fasc. 3, pp.

547-752.— WEISMANN, August. The Evolution Theory. Translated by J.

Arthur Thomson and Margaret R. eger on. London, Edward Arnold, "on

8vo, 2 vols., xvi + 416, + 405 pp.

ALEXANDER, A. B. Statistics #r i Fisheries of the South Atlantic States,

1902. U. S. Fish Comm. Rept. for 1903, pp- 343-410.— ALEXANDER, A.

Statistics of the Fisheries of the Gulf States, 1902. U.S. Fish Comm: Rept. w

1903, pp- 411-481.— ALLEN; J. A. Mammals from Beaver County, Utah, col-

lected by the Museum Expedition of 1904. giu Brooklyn Inst. Arts and Sci.,

Science Bull., vol. 1, no. 5, pp. 117-122.— ASHMEAD, W. H. Descriptions of New

Genera and sees of Hymenoptera from the Pllipplie islands. Proc.

Nat. Mus., vol. 28, pp. 127-158, pls. 1-2.— BaBon, J. F e Weichthiere doi

bémischen Pioni und Holocaen. Arch.f.naturwissensch. Landesdurchforsch.

von Böhmen, vol. 11, no. 5,78 pp.— BARBOUR, E. H. Memoir of Wilbur Clinton

Knight. Bull. Geol. Soc. eh vol. 15, pp. 544- m pl. vnum

Sympterura minveri, n. g. et sp.: a Devonian Ophiurid from Cornwall. Geol.

Mag., dec. 5, vol. 2, pp. 161-169, pl. 6.— BLEININGER, A. V. The Manufacture

of Hydraulic Cements. Geol. Surv. Ohio, ser. 4, bull. 3, xiv + 391 pp.— BOUVIER;

E. L. Palinurides et Eryonides recueillis dans l'Atlantique oriental pendant les

campagnes de l'Hirondelle et de la Princesse-Alice. Bull. Mus. Océanographique

771

772 THE AMERICAN NATURALIST. (VoL. XXXIX.

de Monaco, no. 28, 7 pp. — Bouvier, E. L. A propos des Langoustes longi-

cornes des iles du Cap Vert. Bull. Mus. Océanographique de Monaco, no. 29,

6 pp.— BROLEMANN, H. W. Symphylés et Diplopodes Monégasques. Bull.

Mus. Océanographique de Monaco, no. 23, 11 pp.— BRORUP, R. P. The Doctor

as an Autocrat. Fitzgerald, Ga., 15 pp.— Burrum, B. C. F eeding Experiments

with Lambs, 1903-1904. Univ. of Wyoming Exper. Sta., bull. 64, 20 pp. illus.

— CARBAJAL, A. J. La fiebre carbonosa. Comisión de Parasitologia Agricola,

circ. 17, 4 pp.— CAUDELL, A. N. Orthoptera from Southwestern Texas col-

lected by the Museum Expeditions of 1903, 1904. Mus. Brooklyn Inst. Arts and

Sci., Science Bull., vol. 1, no. 4, pp. 105-116, pls. 6—7.— CHEVALLIER, M. Rela-

tion entre la densité et la salinité des eaux de mer. Bull. Mus. Océanographique

de Monaco, no. 31, 12 pp., pl. 2.— CHEVREUX, E. Description d'un amphipode

(Cyphocaris richardi nov. sp.) provenant des péches au filet à grande overture de

la derniére campagne du yacht Princesse-Alice (1904). Bull. Mus. Océanogra-

Phique de Monaco, no. 24, 5 pp.— CHEVREUX, E. Cyphocaris alicei, nouvelle espece

d'amphipode voisine de Cyphocaris challengeri Stebbing. Bull. Mus. Océano-

graphique de Monaco, no. 27, 6 PP-— CHEVREUX, E. Paracyphocaris predator,

a e

Monaco, no. 32, 6 pp., 3 text figs.— CHITTENDEN, A. K. Forest Conditions of

Northern New Hampshire. U. S. Dept. Agric, Bureau of Forestry, bull. 55,

100 pp.,7 pls., 2 maps.— Coss, J.N. The Commercial Fisheries of the Interior

Lakes and Rivers of New York and Vermont. U.S Bureau of Fisheries, Rept.

fer 1903, pp. 225-246.— Conn, H. W. A Preliminary Report on the Protozoa

of the Fresh Waters of Connecticut. Conn. Geol. and Nat. Hist. Surv., bull. 2,

69 pp., 34 pls.— CnRosBv, C. R. Notes on some Phalangids collected near

Ithaca, N. Y. Jour. N. Y. Ent Soc., Vol. 12, pp. 253-256, fig. 4.— DANÉK,

J. J- Studien über die Permschichten Böhmens. I. II. III. Umgebung von

bömisch Brod, Weaschim und Lomnitz. Arch. d. naturwissensch. Landesdurch-

Forsch. von Böhmen, vol. 11, no. 6, 48 PP.— Dimmock, G., AND Knap, F. Early

Stages of Carabidz. Springfield Mus. Nat. Hist., bull. I, 55 pp., 4 pls.— EDWARDS,

aguey Cultivation in Mexico. P. 7. Bureau of Agric., Press Bulletin, no. 1,

5pP.— Epwarps, H. T. Abaca (Manila Hemp). P. 7. Bureau of Agric., Farm-

ers Bulletin, no. 12, 29 PP., 6 pls.— Eno, F. H. The Uses of Hydraulic Cement.

Geol. Surv. Ohio, ser. 4, bull. 2, xvi + 260 pp.— EvERMANN, B. W.,AND KEN-

DALL, W. C. An interesting Species of Fish from the high Andes of Central

Ecuador. Proc, Biol. Soc. Washington, vol. 18, pp. 91-106, 2 text figs.— FELT,

E. P. Mosquitos or Culicidæ of New York State. New York State Mus., bull.

79, PP. 241-400, 57 pls., 113 figs.— FORBES, S. A., A n

a new Shovelnose Sturg

T L. La faune et la flore glaciaires

Bull. Acad. Roy. Belg., Cl. des Sci., 1904, pp-

Influence de la température sur la distribution

; I p.—FREDERICQ, L. Note sur la

+ von Böhmen, vol. 11 no. 2, 180 Fert

V, à OR OU NE Fa .— Frit, A., AND VÁVRA,

des en me die Fauna der Gewässer Böhmens. V. Untersuchun

usses und seiner Altwässer, Arch. d. neierwiismisch. Longpuerck:

No. 466.) PUBLICATIONS ‘RECEIVED. 773

Jorsch. von Böhmen, vol. 11, no. 3, 154 pp.; 119 text figs.— FULLER, C.A. The

Distribution of Sewage in the Waters of Narragansett sed with Especial Refer-

ence to the Contamination of the Oyster Beds, U. S. Bureau of Fisheries, Appen-

ure, M,

Mex. Coll. Agric. and Mech. Arts, bull. 52, 31 pp.— Garcia, F. Relation of

_ Frosts and Air Drainage to Fruit m. N. Mex. Coll. Agric. and Mech. Arts,

press bull. 101.— GIFFORD, J. G. e Luquillo Forest Reserve, Porto Rico.

U. S. Dept. Agric, Bureau SAP N ers 54, 52 pp., 8 pls., 1 map.— GILL, T.

On the Systematic Relations of the Ammodytoid Fishes. Proc. U. S. Nat. Mus.,

vol. 28, pp. 159-163.— GILL, T. The bit Fish, Neosebastes entaxis, as

the Type of a Distinct Genus. Proc. U. S. Nat. Mus., vol. 28 219—220, 2 figs.

nn T. dee on the Genera of Phan and Pelorine Fi de Proc. U. S.

. Mus. 28, pp. 221-225.— GILL, T. On the Generic Characteristics of

ib B vene Proc. U. S. Nat. Mus., vol. 28, pp. 239-342, 4 figs.— GILL,

T. State Ichthyology of Massachusetts. U. S. Bureau of Fisheries, App. to Rept.

of Commr. for 1904, pp. 163-188.— GORDON, C. H. On the Origin and CE

fication of Gneisses. Proc. Nebraska Acad. Sci., pp. — GOR

C.H. On the Paramorphic Alteration of Nonis ene to Compact ce

Amer. Geologist, vol. 34, pp. 40-43. — GORDON, C. H. On the Pyroxenites

of the Grenville Series in Ottawa County, Canada. Journ. Geol., vol. 12, pp. 31

325, 4 figs.— GRAVE, C. Investigations for the Promotion of the Oyster Indus-

try of North Carolina. U. S. Fish Commission Rept. for 1903, pp- 247-341, 11

pls.— Han N, J. Die chemische ne der fliessenden Gewässer

Böhmens. A mais Hydrochemie der . d. naturwissensch. Landes-

durchforsch. von Bóhmen, vol. 10, no. x 100 pp., (green HANAMANN, J. Uber

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778 THE AMERICAN NATURALIST. | [Vor. XXXIX.

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eport U. S. Agric. Exper. Sta. of Wyoming, 1903-1904,

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Contents, Organization and Membership, Index —Zaragoza, Boletin de la Sociedad

Aragonesa de Ciencias Naturales, vol. 4, no. 2, pp. 29-60.

(Wo. 465 was issued Sept. 16, 1905.)

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THE.

AMERICAN NATURALIST.

Vor. XXXIX. November, 1905. No. 467.

COLLECTION AND PREPARATION OF MATERIAL

FOR CLASSES IN ELEMENTARY ZOÖLOGY.

BERTRAM G. SMITH.

During the past year the writer has frequently received

inquiries concerning methods of collecting and preparing zoó-

logical material for class use. The purpose of the present

article is to give some of the methods used in the Department

of Zoölogy of the University of Michigan in supplying a class

of over a hundred students with laboratory material fora first

course in elementary invertebrate zoölogy. A few organisms

are included that are not ordinarily studied in a beginners'

course, as some of them may be found useful for demonstra- '

tions, or for supplementary work. On the other hand, no

attempt is made to make the list comprise all the forms adapted

to a first year's course; for ecd of these, directions for col-

lecting would be superfluous.

1. Amaba1— Collect the water plant Ceratophyllum, which

will be found growing in the quiet water of ponds and rivers, in

the same habitats with water lilies, Elodea, etc. Gather the

Ceratophyllum in considerable quantities, packing it in pails

1H, S. Jennings. “Methods of Cultivating Amoeba and Other Protozoa for

Class Use.” Journ. of Applied Micr., vol. 6, no. 7, p. 2406.

779

780 THE AMERICAN NATURALIST. (VoL. XXXIX.

with enough water to cover. It is best to get material from

several localities. If Ceratophyllum cannot be found, Elodea

and various other plants may be used, but the results are less

satisfactory.

Bring the material to the laboratory and there set up cultures

as follows. Use “bacteria dishes" — shallow circular glass

dishes, about 9 inches in diameter and 3 inches deep. Pack

the material in these firmy, crushing it down. This will pre-

vent growth of the plant, and favor fermentation. Pack to

within an inch of the top of the dish, and add just enough

water to cover the material. Cover the dishes with glass

plates and put them in various warm and well lighted places

about the laboratory. Each culture should be labeled with the

place where the material was obtained, and the date when the

culture was set up. Later, as organisms appear which are to be

. Studied, their »ames should be added to the labels. Zabel the

dishes, not the covers. If water evaporates so as to expose the

plant material, enough should be added from time to time to

make good the loss.

The first cultures should be started about tree weeks before

the Amoebz are needed. A half dozen cultures should be

Started at this time and several new ones added every two or

three days thereafter, until the class is nearly through studying

Ameeba. The time required for the cultures to mature varies ;

a single culture may last but a few days, and not all are success-

ful — hence the necessity for frequent collections and many

cultures. j

The first indication of Amceba is a brown or a white scum

appearing on the surface of the water. This consists mainly

of bacteria, and the Amoebz come to the surface to feed on

them. Take up a bit of the scum with forceps, mount in a

drop of water taken from the surface with a pipette, tease out

the scum thoroughly with needles, and examine with a micro-

Scope. Amæbæ, if present, will usually be found among or near

the particles of scum. Also, remove a bit of the plant mate-

rial and scrape the slime from it. This will often contain more

Amoebe than the scum at the surface of the water. The speci-

méns are small at first, but in a few days they become larger.

No. 467] ZOOLOGICAL MATERIAL. 781

While the Amoebz usually disappear from such a culture in a

short time, occasionally they persist for a week or more, grow-

ing larger. In some cultures they seem to encyst or disappear

almost entirely, and later reappear in considerable numbers.

Hence old cultures should be watched, and retained until they

become overgrown with fungi and hence worthless.

The advantages of the Ceratophyllum method, as described

and used by Jennings, are that it gives Amoebe in abundance,

at the time desired, with almost absolute certainty. But the

Amcebz obtained by this method are seldom large ; their devel-

opment is often interfered with and they usually give place to

other organisms before attaining maturity. Moreover, the pres-

ence of an excessive amount of bacteria and other organisms

often obscures the Amcebze, and makes it difficult to find and

study them. To overcome these difficulties, the writer, aided

by a suggestion from Professor Reighard, devised a modification

of the above method which has proved a valuable supplement to

it.

As soon as Amoeba appears in the Ceratophyllum cultures,

skim off the brown scum with a spoon, and put it in small bac- -

teria dishes about four inches in diameter and one and one half

inches deep, with enough water to fill the dish about one inch

deep. Add a little of the decaying vegetable material from near

the surface of the Ceratophyllum cultures. This should be done

several days before the Amæbæ are desired for use. Cover.the

dishes and keep them in a warm place, but not in direct sun-

light. In a few days Amoebee will be found in abundance in

some of these cultures, in the scum at the surface or in the ooze

and on the decaying plant material at the bottom of the dish.

Some of the cultures prepared in this way by the writer gave

results far better than were obtained from the ordinary Cerato-

phyllum cultures; the specimens were remarkably large, active,

and numerous. The Amoebz pass through stages of develop-

ment and sometimes practically all of them in a given culture

encyst at the same time. They may reappear later in an active

stage. Later on, among other organisms may appear in these

cultures Arcella, Chilomonas, Parameecium, Vorticella, and occa-

sionally some colonial Protozoa. : :

782 THE AMERICAN NATURALIST. (VoL. XXXIX.

2. Arcella and Difffugia will often be found in ordinary

Ameeba cultures, or in cultures made with dead water-lily

leaves. In rather fresh cultures, these Protozoa may be found

creeping along the surface of the vegetation. Take up a mass

of the Ceratophyllum between the fingers and bruise it briskly

against a watch glass; add a /itt/e water to the residue that

clings to the glass. It will usually contain Arcella and Dif-

flugia.

3. Chilomonas may appear at almost any time in Amoeba cul-

tures ; but it is best to put up cultures especially for Chilomonas

and Infusoria. Use Ceratophyllum and partly decayed water-

lily leaves, and pack in bacteria dishes as for Amoeba, but use

less plant material and more water. Cultures prepared in this

way may mature in a very few days. Mount a drop of the

water containing Chilomonas, together with a little of the slime

or decaying vegetable material by means of which the specimens

may be entangled. |

4. Euglena will appear in some of the cultures put up for

Amoeba, usually after the disappearance of Amoeba, four or five

weeks from the date of starting the cultures, but occasionally it

appears before Amceba. It makes a solid deep-green (not blue-

green) mass at the edge of the dish, especially on the side to-

wards the light. A thick, pale brown, feltlike and granular

scum on the surface of the culture seems to be favorable to

the presence of Euglena. Such a scum contains delicate fungi,

diatoms, desmids, Arcella, etc. '

Euglena usually appears in only a few dishes, but in abundance,

and lasts several days. Euglena is often associated with Phacus,

which somewhat resembles it, but the latter organism is skate-

shaped, and does not exhibit euglenoid movements.

Keeping the cultures away from a strong light may prevent

the formation of an excess of chlorophyll in Euglena.

5. Paramacium — Prepare cultures in the same manner as

for Chilomonas. Decaying water-lily leaves are especially good.

The cultures require but a few days to mature, and last a long

time. Mount a drop of water containing Paramoecia, together

with a little of the decaying vegetable material about which they

may collect. i

No. 467.] . ZOOLOGICAL MATERIAL. 783

6. Vorticella is often found on decaying duckweed, Riccia,

and Ceratophyllum. Place a large handful of the material in a

bacteria dish nearly filled with water. Vorticella often appears

in cultures prepared for other purposes.

7. Carchesium often occurs on water snails and crustaceans

amongst duckweed and Riccia. Collect in the same manner as

Vorticella,

. 8. Volvox has been found to occur most abundantly amongst

duckweed and Riccia, in pools or small ponds that do not dry up.

Collect this material by dipping it up together with a little of the

water and place a small handful of the material, with some of the

water, in each of many bacteria dishes and add enough tap water

so that the dishes are nearly full. Place the dishes so that one

side is strongly exposed to light. After a few hours, specimens

of Volvox may be seen with the naked eye, or with a hand lens,

at the water’s edge on the lighted side of the dish. Remove

them with a pipette to a small covered dish filled with clean

water. . Volvox kept in clear water and strong light seeks the

bottom of the dish, and can readily be found and removed with

a pipette when wanted.. If left in the original dish, there may

be present small crustaceans which will eat them; yet Volvox

may sometimes be collected from these dishes for several days.

Usually the material yields best after a day or two, and in three

or four days becomes worthless. If obtained free from the

animals that prey upon it, Volvox may be kept for several days

or even longer.

Volvox is not always present in localities that seem favorable

for it, and ponds that contain it in abundance are somewhat rare.

In some situations it may be collected to advantage by sweeping

a bolting-cloth net over water plants, or, better, using a “ Birge

net," which has a coarse net over the top for keeping out large

forms and trash. ;

Volvox may be preserved in 4 % formalin. Formalin speci-

mens show flagella better than living ones. On account of the

uncertainty of obtaining Volvox late in the fall, a supply of pre-

served specimens should be laid in early in the season. —

In studying Volvox, mount the specimens in hollow slides or

on ordinary slides with cover-glasses supported by fine glass

rods or by bits of broken cover-glass. ipi :

784 THE AMERICAN NATURALIST. [Voı. XXXIX.

9. Pandorina sometimes forms a green scum on the surface

of the water amongst water lilies, or on the lily leaves.

IO. Hydra occurs most abundantly on the following plants:

duckweed, Riccia, Ceratophyllum, Elodea, watercresses. Two

methods of collecting may be used. (a). Method best adapted

to duckweed and Riccia: bring in the material with enough

water to keep it moist. Fill a large number of bacteria dishes

nearly full of clear water. Place in each dish a small quantity

of the plant material — scarcely enough to cover the surface of

the water on which it floats. Place each dish so that one side

will be exposed to the light. A day or two later hydras will be

found in the extended condition, clinging to the side of the dish,

especially the lighted side, to rhizoids of plants, or to dead plants

and sediment at the bottom. They may be removed from the

sides of the dish with a pipette, or if clinging to plants, the lat-

ter may be removed with forceps. Place the hydras in a covered

dish of clean water with a small amount of actively growing plant

material. Here they will keep indefinitely and may readily be

found when wanted. It is not safe to leave them in the original

dishes, as there may be present crustaceans which will eat them,

or an excess of vegetable matter may cause the water to become

foul, which is unfavorable for Hydra. However, the dishes

should be inspected daily, for sometimes the material will yield

Hydra indefinitely.

(b). When Hydra is to be obtained from large plants like

Ceratophyllum and Elodea, the best method is as follows: place

a considerable quantity of the plant material in each of several

"large-bacteria dishes and cover it with water. Ina short time

the water becomes foul through the decomposition of vegetable

matter; the hydras then loosen their hold upon the vegetation

and may be found floating at the surface of the water. They

must be picked off at once with à pipette and removed to clean

water.

Hydra will reproduce readily by budding if kept in a fairly

"m room; but the optimum temperature is not very high.

It is said that if Hydra is kept in the dark at a slightly lower

temperature than usual for several days, this will favor the

formation of spermaries and ovaries. Rarely, a mature fertil-

ized egg in the winter Condition may be found.

No. 467.] ZOOLOGICAL MATERIAL. 785

II. Planarians are found on the under side of stones in run-

ning water. They are usually abundant in a locality if found

there at all. They may be removed from the stones by means

of a thin wooden toothpick, and placed in a bottle of water for

transportation.

12. Earthworms. — The collection of earthworms should be

attended to as early in the fall as possible, as dry or cold weather

may make it impossible to get them later. It is well to lay in

a supply of preserved worms during the spring or summer.

Specimens to be kept alive should perhaps not be collected

until after the first of October, but it will be unsafe to wait

much longer. Each student will need two or three preserved,

and one or two living specimens.

The form used in the Zoólogical Laboratory of the University

of Michigan is Lumbricus herculeus Savigny. The specimens

range in length from about 6 to 11 inches, with an average of

about 8 inches. They come out of their burrows on warm, rainy

nights, usually lying extended with the posterior end of the body

still in the entrance of the burrow. They are most abundant in

old, rich gardens and lawns. Go out with a lantern and a pail

after it has become quite dark; the harder it rains the better.

By stepping lightly and not allowing the light to shine upon

them too long, one may seize the worms with the hand. To

catch them requires quickness and dexterity ; but they must be

pulled gently from the burrow.

When brought into the laboratory the worms that are to be

preserved for dissection should be placed immediately in covered

bacteria dishes (9 inches in diameter by 3 inches deep) between

sheets of moist filter paper; the covers should be adjusted so

as to admit a littleair. Not more than twelve specimens should

be placed in a dish, as they will soon die if large numbers of

them are left together. The dishes should be kept in a cool

place, avoiding direct sunlight. In the morning the paper

should be changed, and injured or dead specimens removed;

the operation should be repeated as often as is necessary. After

a day or two the worms will have eaten enough moist filter

paper to clean the alimentary canal of earth, and are ready for

preservation.

786 THE AMERICAN NATURALIST. [VoL. XXXIX.

Worms to be kept alive for a considerable length of time!

may be placed, immediately after collection, between folds of

moist muslin in bacteria dishes, with not more than a dozen

specimens in a dish. Change or wash the cloth occasionally —

at least every two weeks. The worms may be fed on leaves,

etc., if desired. With proper care, they will keep in this way

for months, and are always clean and ready for use at a mo-

ment's notice. The writer has found that the worms will keep

quite as well if filter paper is used instead of muslin. |

Preparation of Earthworms Jor Dissection.— Fresh specimens

are too soft for convenient handling of the tissues during dissec-

tion ; it is also inconvenient to keep a sufficient number of them

alive for general dissection purposes ; hence preservation is

resorted to. Two methods are available : —

. (a) Chromic Acid Method.

I. Killing— Place in 4% alcohol and gradually increase the

strength to 8% in the course of the next two hours by adding

Stronger alcohol a few drops at a time. Wash in water to free

from mucus and again immerse in 8 % alcohol until the worms

are thoroughly stupefied and no longer contract when pinched

with forceps.

2. Fixing.— Inject worms with 1 % chromic acid and immerse

in the acid for about 4 hours.

The injection. is best performed by means of a water pressure

apparatus (see Fig. ı). This gives constant, uniform pressure.

A head of about four feet of water should be used. A glass

cannula may be made by drawing out the end of a piece of 1 inch

glass tubing to a very fine bore, and breaking it so as to leave a

sharp point with a raw edge. The exact size must be determined

by experiment. The stream may be allowed to flow continuously

from the cannula. A pipette with point drawn out fine may be

used in case this apparatus is not available, but it is not very :

satisfactory,

1 i i |

H. S. Jennings. « Keeping Earthworms Alive in Winter." Journ. of Ap-

plied Micr., vol. 6, no. 7, PP- 2412-2413.

No. 467.] ZOOLOGICAL MATERIAL. 787

Fill a large shallow glass dish about à inch deep with 1 %

chromic acid. (Cover the hands and wrists thickly with vaseline

while working with chromic acid.) Take each worm separately

and lay it in an extended condition in the chromic acid, keeping

it straight and seeing that it is not twisted. Inject immediately,

Fic. r.— Constant pressure injection apparatus. a should be filled with water, part of

which flows into 4; ¢ contains injection fluid,

about 4 inch behind the clitellum, and again near the posterior

end of the body if necessary. /mject into the body cavity; be

careful not to pierce the alimentary canal. The worm should

swell out slowly along its entire length and become very turgid.

Too rapid injection may tear the tissues.

The worms should be kept straight while in chromic acid. If

left in the acid less than four hours they will eventually become

too soft ; if left in the acid much more than four hours they will

be too brittle.

Wash thoroughly in running water until the yellow color is

gone —about 12 hours. Be sure that the water reaches every

part of the surface of each worm. If free acid remains on the

worms it will make them brittle. The worms are a light drab,

not yellowish brown, when well washed.

788 THE AMERICAN NATURALIST. (VoL. XXXIX.

3. Preserving.— Place the worms in 50% alcohol and leave

for a day or two; the alcohol will become discolored by chromic

acid. Change to 70% and leave a day or two longer. Then

change to the same grade (70%) for final preservation.

The alcohol will complete the process of removing free acid

and will further harden the tissues. Stronger grades of alcohol

than 70 % are not advisable for preservation, as they may cause

the more delicate tissues to become brittle.

(b Alcohol Method.

Kill as directed under chromic acid method. Place the

worms in 50% alcohol, keeping bodies as straight as possible.

Leave 4 or 5 hours, then place in 70% alcohol and leave over

night. Next morning place in 96% alcohol to harden them,

and leave all day. Change to 70% alcohol for final preserva-

tion. i

Choice of Methods.— Specimens hardened in chromic acid are

most satisfactory for general dissection purposes. The tissues

are firm and leathery, and are not affected by water during dis-

section, hence they may be dissected under water instead of

alcohol. This is a decided advantage. The largest and best

marked specimens should be put up in this way.

The alcohol method of fixing is not so satisfactory for most

purposes ; the body wall and tissues generally are too soft to be

conveniently handled unless the dissection is done under alcohol.

But the method has the advantage of simplicity, and the smaller

and more poorly marked specimens may be put up in this way

for use in case other material runs short. Alcoholic specimens

do very well for the study of the nervous system.

Fresh Specimens are not only necessary for the study of the

living worm, and for demonstrations of cilia, blood, coelomic

fluid, spermatozoa, etc., but are best for the study of the circu-

latory system and the nephridia.

For studying the circulatory system the living specimen may

be stretched out in a dissecting tray and fastened with a pin

through each end of the body ; if desired it may first be stupe-

fed with alcohol. The dissection should be carried on under

No. 467.] ZOOLOGICAL MATERIAL. 789

normal salt solution (0.75% NaCl). In the absence of living

specimens, chromic-acid specimens do fairly well for the circu-

latory system.

For sectioning with a microtome it is necessary to have speci-

mens with intestines entirely free from grit. Worms that have

been kept in clean, moist muslin for a considerable length of

time will usually be found to have the alimentary canal free

from all undesirable substances. The muslin should be

changed every day, and the worms must not be fed. A quicker

method ! is to flush the alimentary canal by means of an injec-

tion apparatus. Use a cannula with a rather large opening ; the

proper pressure must be determined by experiment. Stupefy

the worms with dilute alcohol (3 to 6%). Inject the alimentary

canal from the posterior end with 0.75 % salt solution ; roll the

body of the worm back of the clitellum between the fingers and

strip out the contents of the intestine. Then inject from the

anterior end; this time the stream will go entirely through.

Avoid too much pressure, as it will injure the tissues. Roll and

knead the body while the stream is being started through. The

fluid should be forced through the worm until it comes from the

posterior end in a perfectly clear stream. The worm is then

ready for fixing.

ZoóLoGICAL LABORATORY, UNIVERSITY OF MICHIGAN,

ANN ARBOR, MICH.

1 Raymond Pearl. Fourn. of Applied Micr., vol. 3, no. t, p. 680.

A NEW OSTRACOD FROM NANTUCKET.

JOSEPH A. CUSHMAN.

DuniNG the spring of 1905, several members of the Nan-

tucket Maria Mitchell Association made collections from the

various bodies of fresh water on the island. This material was

kindly turned over to me for study. Among other noteworthy

things is an ostracod of the genus Cyprinotus that is apparently

new. Its description follows : —

Cyprinotus americanus sp. nov.

Plate 1, Figs. 1-8.

Length of male 1.5 mm., width 0.7 mm., height 0.8 mm.

The length of the shell is a little more than twice the width and the

height is slightly greater than the width. The shell is thin, translucent,

free from bands or color markings of any sort (Pl. 1, Fig. 1).

Viewed from the side (Pl. 1, Fig. 1) the shellis suboval, with the greatest

height slightly more towards the cephalic end. The dorsal margin is con-

vex, the cephalic end much more convex than the caudal, which is almost

bluntly pointed. The ventral margin is also slightly convex.

Viewed from above (Pl. 1, Fig. 2) the shell is narrowly elliptical with the

. anterior end more rounded than the posterior.

` The third joint of the antenna is toothed on the distal part of each side,

with one of the angles clothed with fairly long hairs. The single seta from

this angle is doubly fringed. The last joint is short and bears two of the

four terminal claws, these latter being finely toothed. The natatory sete

extend to the end of the terminal claws. The characters of the antennules

are shown in Fig. 4 (Pl. 1). The setz from the last joint are much shorter

than those from the preceding ones. The characters of the mandible are

very distinctive. The sete of the upper joint are peculiar, all of them

being doubly fringed with scattered hairs. The large terminal setz are

fringed on a single side. The third joint has many short spines on its ven-

tral side. The jaw of the mandible has compound teeth of which the ante-

rior ones are comb-like in structure. Lue

The first foot has a long terminal claw the distal part of which is finely

toothed. The fourth joint bears four short spines. The second joint has

791

792 THE AMERICAN NATURALIST. (VoL. XXXIX.

two long curved spines in addition to the setze. The second foot has a pecu-

liar clawlike extremity. The last joint is constricted in the middle and

the distal portion bears two rows of minute spines.

The rami of the postabdomen have two long claws, finely toothed along

their whole length. The proximal small seta is considerably removed from

the others.

Habitat. — Specimens collected from Grove Lane Ditch near the town of

Nantucket, Mass., April 3o, 1905, by Miss Marianna Hussey.

In many ways this species most closely resembles C. burling-

tonensis Turner but is different in its proportions and in the

distribution of the setze on the appendages as well as in their

spinosity, and the shape and set of the mandible.

No. 467.]

A NEW

OSTRACOD.

PLATE I.

ig. r.— Shell viewed from the side. X 40-

Fig. 2.— Shell viewed abo X 40.

Fig. 3.— Antenna. É

Fig. 4— Antennule. X 200.

793

hi inte hy mistake

+ 7

FURTHER NOTE ON ZYLA ANDERSONII AND

RANA VIRGATIPES IN NEW JERSEY.

WILLIAM T. DAVIS.

IN Cope's Batrachia of North America, and in other works

treating of our native frogs, Hy/a andersonii Baird is said to be

rarely met with. In the note on this species by the writer pub-

lished in the American Naturalist for November-December,

1904, that view was also taken, but it must now be accepted as

a fact that Hyla andersonii is anything but a rare frog in certain

parts of the New Jersey pine barrens.

At Lakehurst, New Jersey, especially in the latter part of May

and in June, there may be heard at evening coming from the

white cedar swamps, many voices that resemble the familiar

quacking of ducks. If one will take the trouble to wade into one

of these swamps at twilight and approach the singer cautiously,

it will be discovered that he is a male Hyla andersonii. He pipes

up and sings *aqguack-aquack-aquack " many times, or until his

bubble of air gives out. This is the time, while he is singing, to

take a step forward. Even when the observer is very near and

evidently plainly in his view, he cannot resist the temptation

to sing, for he hears his rivals all about calling loudly. The

notes are not all alike in sound, and some individuals remind one

of the * potrack-potrack” of the farmyard Guinea fowl The Hyla

will be found seated on the lower limb of some tree, or among

the top branches of a huckleberry bush. I have heard this frog

singing at mid-day when the sun was shining brightly, especially

after a shower. Also solitary individuals may be heard in the

swamps much later in the year, and they do not appear to

wander as far from the water as does Ayla versicolor.

Rana virgatipes Cope is also more abundant at Lakehurst

than at first supposed, and has been found from May to Sep-

tember. In the early summer as many as twelve have been seen

in one day without much search having been made for them.

795

796 THE AMERICAN NATURALIST. [VoL. XXXIX.

They are apt to be in some ditch and seated on the sphagnum

moss, or on a floating lily pad, and they are found also in the

ditches that border and intersect the cranberry bogs, as well as

in the lake.

A SYSTEMATIC STUDY OF THE SALICACE.

(Concluded.)

D. P. PENHALLOW.

ANATOMY.

The Growth Rings. —So far as may be judged from an

examination of fifteen species of Salix and eleven species of

Populus, growth rings of somewhat great radial extent appear

to be a general characteristic of the Salicacez. Such a feature

is directly correlated with, and in fact may be taken to be a

resultant of the very free growth for which the members of

this family are, in general, conspicuous. Partial exceptions

have been observed in the medium growth rings of Populus bal-

samifera, P. monilifera, and P. heterophylla, as also of Salix

scouleriana ; but slight deviations of this nature cannot be re-

garded as expressing a general law, since as has been shown by

Peirce (: 04), they may well have arisen in response to injuries

inflicted by insects or other agencies, or they may simply be

an expression of periodicity in climatic conditions. The same

statement cannot be said to hold true in equal measure of Pop-

ulus alba and P. grandidentata, since in both of these species

the generally narrow and uniform growth rings seems to point to

specific differences. These observations are greatly strength-

ened by the fact that Salix uva-ursi presents a noteworthy

deviation from the general characteristics of the family. Its

growth rings are not only narrow, but they are variable and

strongly eccentric. Such characteristics are very readily under-

stood when the natural habitat of this plant is recalled. Grow-

ing in the Alpine Garden on Mt. Washington at an elevation of

about five thousand feet, its development is accomplished under

the influence of a very short, season the character of which

must vary in an exceptional manner from year to year, while the

prostrate habit would also establish marked eccentricity of

797

798 THE AMERICAN NATURALIST. (VoL. XXXIX.

growth. This case is therefore to be regarded as lying outside

the normal course of development for the family as a whole,

while at the same time it serves to give emphasis to the specific

effects of external influences in modifying the character of the

growth.

It is a general feature of the Salicaceze to which there are no

well defined exceptions of a noteworthy character, that there is

substantially no differentiation of spring and summer wood.

Partial exceptions seem to be shown by Sa/ix longifolia in which

the last six rows of cells sometimes become radially compressed,

or by S. cordata and S. /evigata in which three rows are some-

times so modified. The fact that in all these cases the modifi- `

cation is not a constant feature, but that it arises sporadically,

indicates clearly that it is due to some exceptional and transitory

influence, and that it does not in any way express the usual

characteristics of growth. On the contrary, it is not an uncom-

mon feature in S. zzgra for the first half of the growth ring to

present the most dense structure, this being due, not to a

diminution of the vessels with a relative preponderance of the

fibrous mechanical cells, but to the fact that the latter are char-

acterized by thicker walls than elsewhere, with a corresponding

diminution of the cell cavity. Inthe investigated species of

poplar, there seems to be no deviation from the general rule

thus expressed. In both genera there is substantially no altera-

tion in the form and size of the wood cells as between those of

the inner and those of the outer face of the growth ring (Figs.

6, 7), and the demarcation between the growths of successive

seasons is determined by other factors of which the occurrence

of a limiting zone of resinous wood parenchyma is the most im-

portant. From these considerations it appears that the charac-

od of the growth ring, in its more general aspects, possesses no

diagnostic value for specific purposes, or even for generic differ-

entiations, but that it may be regarded as of value for ordinal

purposes with respect to their great breadth and the absence of

any marked differentiation between the spring and summer

woods. Since the radial compression which is generally so dis-

"dos a feature of the summer wood, is recognized to result

rom increasing cortical pressure (De Bary, '84, p. 501) it must

No. 467 STUDY OF THE SALICACEE. 799

be inferred from the observed structural conditions, that in the

Salicacex as a whole, the bark expands or ruptures in such a

way as to provide a minimum of pressure which is practically

uniform during the entire period of growth.

The Transition Zone — The protoxylem region in the Sali-

cacex, or what may with more propriety be termed the ¢ran-

sition zone in accordance with the previous use of that term

(Penhallow, : oo, : 04c), is exclusively confined to the growth of

the first year in accordance with the general law of growth

which governs the Dicotyledonous angiosperms, and the follow-

ing observations must therefore be interpreted in that sense.

So far as our studies have gone, they show that in the arbo-

rescent Salicaceze, whether Populus or Salix, the transition zone

is narrow and that it consists almost exclusively of a few spiral

and scalariform elements. I have as yet been unable to discover

in such forms, any extension of the protoxylem which would

admit of transitional forms of the elements. The transition from

the primitive protoxylem elements on the one hand, to com-

pleted forms of wood cells without pits, and of broad vessels

with hexagonal pits on the other hand, appears to be developed

with great abruptness. These features appear to be so well

defined and constant as to make it apparent that the transition

zone has been so far reduced as to approach the point of actual

extinction.

In 1897 an opportunity was presented to collect some stems

of Salir uva-ursi from the Alpine Garden, Mt. Washington.

At that elevation the greatly reduced shrubs are forced to

assume a prostrate habit of growth, in consequence of which

the rather slender and somewhat sinuous stems are buried un-

der a considerable accumulation of plant débris. In such sit-

uations, although there is usually an abundance of water during

the summer, the plant is of a somewhat xerophilous habit as

made evident by the reduced and somewhat coriaceous foliage,

in obedience to the low temperature and the consequent inability

of the roots to provide for an actively moving transpiration WE

Schimper (: 03). This xerophilous habit

ral structure of the wood as may

osis, from which it will be

rent, as pointed out by

is also expressed in the gene ;

be observed by reference to the diagn

800 THE AMERICAN NATURALIST. [Vor. XXXIX. |

noted that the vessels are very small and there is a relative pre-

ponderance of the mechanical tissue. Assuming that the wil-

lows originated under the influence of a relatively warm climate

as we have reason to believe must have been the case on the

basis of evidence brought forward by Wieland (:03), it is evi-

dent that Sax uva-ursi in common with other boreal and alpine

forms, must represent a degenerate type which has been re-

duced under the influence of a diminishing temperature. But

such reduction has clearly involved a loss of the originally erect

position, and in consequence of the diminished necessity for

mechanical support, it might be inferred that there would be a

more or less pronounced tendency to reversion in such wise that

the transition zone would tend to regain its primitive character

to some extent, and that it would once more exhibit those devel-

opmental features of structure which have essentially disap-

peared from the great majority of species as now known. It

was therefore felt that this plant might offer exceptional oppor-

tunities for a solution, in part at least, of the question as to the

actual genesis of the vessels and the wood cells, and their

mutual relations. The stem selected for study was of a some-

what sinuous form and in cross section ovate, the diameters

being 1.20 and 1.80 cm., with the pith eccentrically placed to-

ward the narrower or under side, the major axis of the cross

section being oriented vertically. Longitudinal sections were

cut from this stem at a slight angle with its principal axis, and

in such number as to embrace not only the entire pith, but a

considerable portion of the secondary xylem lying on opposite

sides. It will thus be observed that while some of the sections

were strictly radial their character gradually changed as the

relation of the plane of section to the radius changed, until

they became strictly tangential. It thus became possible to

study the elements of the transition zone from these two points

x en and in a progressive series, But owing to the slight

M plane of section to the longitudinal axis of the

, section would exhibit at one end the radial aspect

= won iens ie the tangential aspect, while between the

Se a graduated series of changes showing all

re radial extent of the transition zone. This

No. 467.) STUDY OF THE SALICACEE. 801

was found to be of special importance because the protoxylem

is so localized and forms such small groups, while the transition

elements are so scattered, that many radial sections might be

examined without furnishing conclusive results. The diagonal

plane of section, on the other hand, cuts through the entire

radial extent of the transition zone and is certain to display

whatever transition forms may be present. In this way it was

possible to obtain the figures now presented.

The rather scanty pith is composed of isodiametric and some-

what thick-walled cells of large size, which, at the periphery,

become greatly reduced in size without any diminution of the

absolute thickness of the walls, assume the form of short cylin-

ders, and function as resin-bearing parenchyma. There is thus

produced a strongly resinous zone of tissue in immediate con-

tact with the protoxylem and enclosing it on the radially inward

face as well as the two tangential faces. It is not difficult to

determine that the protoxylem consists primarily and chiefly of

the usual spiral and scalariform tracheids which are common to

the same zone in others of the Salicacez ; but a careful exami-

nation of the diagonal section shows that there are other ele-

ments of a transitional character not to be met with, so far as

I am aware, in other species having an upright habit of growth.

A somewhat .detailed account of the features noted will be

essential. ;

The protoxylem elements proper consist of a few spiral trache-

ids characterized by very flat and close spirals. Such elements

commonly have very abrupt and often transverse terminations.

The length varies very much, $0 that while in most cases long,

short. As exposed in sec-

s are seen not to be sim-

s most recently

general effect of thi

the appearance of a continuous series of coni

pits. This fact also makes it clear that the spirals of Salix have

lost the simple and primitive character of those bands which are

to be met with in the protoxylem of the gymnosperms, or even

in many of the vessels of the Monocotyledons, and that they

802 THE AMERICAN NATURALIST. (VoL. XXXIX.

have distinctly approached that modification which must imme-

diately precede the formation of bordered pits. Such a feature

serves to show that the transition from spiral to scalariform

structure might be accomplished without any very conspicuous

transitional forms such as have been shown to exist in the case

of Cordaites, and such as are found not to exist in the Salicaceze

as a rule; while it also serves to explain in part the great radial

diminution of the protoxylem of the Salicaceze as compared

with that of more primitive forms of plants. In addition to the

spiral tracheids, the protoxylem also includes a certain num-

ber — generally few — of scalariform elements. These approxi-

mate in form and size to the spiral tracheids though they

often have distinctly tapering extremities, in which respect they

approximate very closely to the fibrous mechanical elements

or wood cells of the secondary xylem (Fig. 1). It

has also been observed in such cases, that the

scalariform markings become distinctly fewer and

more distant (Fig. ı) as if certain of the pits had

been obliterated by a more general secondary

thickening of the wall, and that such is the true

explanation we are justified in believing from a

study of the transition zone in Cordaites (Penhal-

low, :00, :04c). That such obliteration has not

proceeded at a uniform rate throughout the length

of the cell, is evident from the figure given. When

such scalariform markings are exposed in section,

they exhibit precisely the same bordered structure

mp m in the case of the spirals. The most interior

waursi. Ta. Portion of the secondary xylem sometimes contains

pep cuam SCalariform elements of a transitional form. In

tracheid show. Such cases the scalariform structure is irregular

Ma Iu and very imperfectly developed upon both the

radial and the tangential walls, presenting an

obvious form of transition in the direction of the bordered pits,

chiefly expressed in the shortening of the individual pits and

their more definite segregation. But such changes in the

Structure of the cell wall might equally well be precedent to

the complete and final obliteration of the pits of whatever form,

No. 467] STUDY OF THE SALICACEE. 803

a view which is justified not only by the reduction in size and

IG. 2.— Salix uva-ursi.

Tangential sections of

tracheids with bor-

dered pi

wood cells.

(Figs: 2, @,- a).

and usually a

length (Fig. 2, c), there is a strong tendency

to a multiseriate ar

fully expressed in the completely developed

vessel as shown in Fig. 5.

cheids, there is conside

tribution of the bordered pits.

many instances of pits on both the

tangential walls (Fig. 3),

to the vessels as shown in Fig. 5,

will be noted that when such a vess

upon a fibrous wood cell,

number of the scalariform markings, but by

the irregular manner in which such reduc-

tion proceeds, so that the pits often lack that

regular and definite disposition so character-

istic of the bordered pits; and finally it is

justified by the fact as shown in Fig. 1, that

the scalariform markings are often wanting

on the radial walls while characteristically

developed on the tangential walls.

The earliest secondary xylem is character-

ized by the presence of true fibrous tracheids

distinguished by the presence of bordered

pits. These tracheids as shown in Figs. 2

and 3, are all tapering or of the fibrous and

fusiform type, and they vary very much in

length and breadth. In those

of the most slender form,

there is but a single row of

bordered pits which diminish

very greatly in size as the end

: uo

of the tracheid is approached iE

With an increase in breadth mS

corresponding diminution of

® DOO

rangement which becomes

In such fibrous tra-

rable variation in the dis-

Thus we find

radial and

a distribution COMMON & , Salix uva-

although it wre. Tangential

eb abus — Quse dum

there are no bordered v ser

: : n to the two. :

pits on the radial wall commo pean regc une

This fact is expressed in

in the case of the fibrous t

other ways. Thus wails, and resinous

racheids in Fig. 2,

804

THE AMERICAN NATURALIST. (VoL. XXXIX.

it will be seen that the pits are confined chiefly to the tangen-

pitted tracheid.

X 350.

tial walls, and appear on the radial walls at the

ends only of the tracheids (Figs. 2, a, c), or they

may even be completely eliminated from the radial

walls as in Fig. 2, 4. Such variations are also to

be seen in Fig. 4. One variation of such relations

worthy of note, was found in radial section. A spi-

ral tracheid of the protoxylem was immediately fol-

lowed on its outer side, by a fibrous tracheid with

round, variably distant bordered pits in one series.

The tangential wall common to the two was also

provided with a continuous series of bordered pits.

Immediately outside the fibrous tra-

cheid, and therefore on the side oppo-

site the spiral tracheid, was a fibrous

wood cell presenting no pits of any

kind upon either its radial or its tan-

gential walls. The illustrations thus -

given in detail, serve to illustrate the

general fact that all sorts of transi-

tional forms are to be found, con-

necting the fibrous elements of the

secondary xylem with the cylindrical

and more or less tubular elements of

the protoxylem ; and it is quite evi-

ent that we have in Safir uva-ursi

the same sort of a transition zone as

D Boe >>

OOO

OLG

OION

E >

v (ct

1G,

RUN

(2)

that which has already been shown to exist in the

gymnosperms (Penhallow, :00), the two cases dif-

fering chiefly with respect to (1) the radial extent

of the zone, (2) the number and extent of the tran-

sition. forms, and (3) the specific character of the

final products. When we consider the various

transformation stages occurring in Salix uva-ursi,

the peculiar conditions of reduction in the struc-

tural details of the cell wall, the special alterations

in the form of the individual elements, and the

cells, the muiti-

seriate bordered

pits on both ra-

brous tracheid.

peculiar association of these derived forms, it is exceedingly

No. 467] STUDY OF THE SALICACEE. 805

difficult not to feel that we have before us an expression of

evolution in two directions from the protoxylem, the one lead-

ing directly to the formation of vessels with multiseriate

bordered pits; the other leading to the formation of purely

mechanical and fibrous elements wholly devoid of pits, or in

which the latter survive in the form of simple, sporadic per-

forations of small size. As far as it is possible to interpret

the alterations of structure so far observed, the following would

seem to be the sequence of events : —

Protoxylem.

Spiral tracheids with close spirals set at a low angle and showing a bor-

dered pit structure in section. Terminations usually abrupt.

Scalariform tracheids with abrupt or tapering extremities ; the markings

showing a bordered pit structure in section. Transitional forms numerous.

Markings often obliterated from either the radial or the tangential walls.

Secondary Xylem.

The elements diminish in breadth

and increase in length.

Bordered pits are at first present

on both the radial and the tangential

The elements diminish in length

and increase in breadth.

The bordered pits on both the

radial and the tangential walls are

successively I-, 2-, and multiseriate.

The vessels thus formed are mul-

tiplied in large numbers ; they serve

the purpose of circulation ; they are

reproduced as features of the sec-

ondary wood of each year's growth ;

they do not form a definite zone or

medullary sheath after the first

year; their functional activity may

be arrested by the excessive develop-

ment of thyloses or other causes;

they constitute a relatively small

portion of the entire structure ; they

contribute to the greater porosity

and diminished strength of the struc-

ture as a whole. :

walls; at first one-seriate, they di-

minish in number and become more

strictly segregated; they become

more strictly confined to the radial

stress, to which end they are especi-

ally adapted ; they constitute the

stem, to which they impart hardness,

solidity, rigidity, and durability.

806 THE AMERICAN NATURALIST. (VoL. XXXIX.

A comparison of these evolutionary phases with mos PURT

determined for Cordaites (Penhallow, :00, p. 57, and ; nn

250) will show that thetwo are essentially parallel, nn. TE

one another only in detail in the two directions alrea y at d

So far then as the Salicacez are concerned, there is abun an

supplementary evidence to show that in that family e és = $

the gymnosperms, the evolution of the secondary xy des BER

protoxylem is determined by the special requirements o iae i

and the movement of the transpiration current ; that the fibrous,

non-pitted wood cells serving the ends of mechanical EE

derived from the spiral tracheids in the first instance rx à;

the relative predominance of mechanical or conductive tissue, :

the resultant of influences acting along two distinct lines o

ment.

m, Cells.—Very little diagnostic value attaches pes

appearance or disposition of the wood cells as presen =

transverse section, and such features as they do exhibit are rather

of ordinal than of generic or specific value. They are mre

hexagonal and very variable as to size. Usually they are ees

posed in a very irregular manner, though occasionally there is a

more or less pronounced tendency to disposition in radial rows,

but in no case is this so pronounced as in the Coniferae — a poy

ence which may be said to distinguish the gymnosperms from al

the higher types of woody plants. The walls are of medium

thickness, a feature which seems to be consistent with the gen-

erally soft character of the woody structure, and, as already

pointed out, there is a complete absence of that unequal, regional,

secondary growth of the cell wall which, in other woods, con-

tributes so largely to a differentiation of the spring and summer

woods. On the whole, the structure of the mechanical tissue is

closely comparable with that of the Rhamnaceæ, a resemblance

which will be found to extend to other features of the vascular

zone.

Wood Parench yma. — In

parenchyma varies considerab

Structure. Within the re

ments are more or less

vessels, the tendency is to

its transverse section, the wood

ly according to its position in the

gion of the medullary sheath the ele-

isodiametric ; when associated with

compression conformably with the

No. 467.] STUDY OF THE SALICACEE. 807

radius of the vessel; when forming isolated tracts, they tend to

assume the form of the associated wood cells ; but when occur-

ring in the limiting zone of a growth ring where they are chiefly

to be met with, they are invariably compressed in a radial direc-

tion, thereby assuming a form which serves to distinguish them

from the associated mechanical elements.

In their longitudinal aspects there is little that is not common

to such elements wherever they may be found. They are cylin-

i l i } i i t f . X .

Fic. 6.— Salix alba. T t g the genus 52

drical elements with somewhat thick and pitted walls, and abrupt

or transverse terminations. In the medullary sheath they are

generally only a few times longer than broad, but within the

region of the secondary xylem, and especially in the limiting

zone of the growth ring, they become much longer and propor-

tionately narrower. Such features, however, whether exhibited

in transverse or longitudinal section, are of an altogether gen-

808 THE AMERICAN NATURALIST. (Vor. XXXIX.

eralized type, and they possess no value for differential pur-

poses. The wood parenchyma is always characterized by the

presence of resinous matter which is generally deposited in

large quantity, and it thereby gives a distinguishing feature ,

to the elements which admits of their very ready recognition.

This is especially true of them in the region of the medul-

lary sheath, but it is also equally true in some other cases.

The distribution of the resinous wood parenchyma as dis-

Li :

NIIT

LEI PR

Fic. 7.— Populus —« Transverse section showing the characteristic structural

u of the genu C $2.

played in transverse section, presents features of special value

for diagnostic purposes. In all of the Salicacez it forms a

thin, limiting zone on the outer face of the growth ring. This

zone varies somewhat in thickness and continuity, but as a

rule it is composed of a continuous series of cells forming à

layer from one to three elements thick (Figs. 6, 7). But in the

No. 467.] STUDY OF THE SALICACEZ. 809

genus Salix, other features of importance for differential pur-

poses are presented.‘ Thus in S. cordata the cells occur in large

numbers throughout the woody zone, and are distributed in such

manner as to form rather conspicuous and often somewhat exten-

sive tracts disposed without any reference to an orderly arrange-

ment. In S. sessilifolia and S. longifolia, it not only occurs in

the limiting zone, but it is also definitely associated with the

Fıc. 8.— Populus tremuloides. Tangential section. X 52-

in S. cordata, forming about them a narrow but

discontinuous layer, or as isolated cells at various parts ve ”

periphery. All other species of Salix, so far as € Y

present investigations, have the wood parenchyma p n

the limiting zone of the growth ring, à rule which also seem

to apply to Populus without exception.

The a The chief diagnostic value o

vessels as

f the vessels is to

810 THE AMERICAN NATURALIST. (VoL. XXXIX.

be found in their distribution and compounding as exposed in

transverse section, but before considering these features, it may

be well to discuss the few details relating to their aspects in

longitudinal section.

Thyloses are a general feature of the vessels in wood of the

Salicacez, but they differ in some important essentials from

those with which we are familiar in other woods, e. g., Catalpa

or Pinus. They generally fill the cavity of the vessel so com-

pletely (Figs. 6, 7) that in transverse section they seem to be

entirely wanting. This is due to the fact that they undergo no

longitudinal division, and as a result there is only one thylosis

transversely, which is closely applied to the wall of the ves-

sel. It will nevertheless be observed that in longitudinal sec-

tion, instead of the modified spherical form usually assumed in

woody stems, the thyloses of the Salicacez are really in the

form of long, cylindrical cells several times longer than broad,

but of very variable length. It is this last feature among others,

which results in their apparent absence from the transverse sec-

tion, since a given plane of section is most likely to pass be-

tween terminal walls, and as the thyloses lie in a single series,

there are no longitudinal walls to break up the cavity of the

vessel.

Apart from the well known structure which distinguishes all

the vessels of the wood in angiosperms, it will be found that the

radial walls are characterized by bordered pits which are chiefly

somewhat distant, sometimes conspicuously so, and in conse-

quence they are either oval or round (Fig. 10). It is rather

the exception that they are so aggregated as to become hexag-

onal. On the other hand, in the tangential section, the pits are

invariably crowded together to such an extent that they are

typically hexagonal (Fig. 11), and the space between contiguous

ps ts represented by only a very narrow line of secondary wall

jomed directly to the primary wall. These differences will be

found m exact accord with the distribution of the pits on the

radial and tangential walls as described for the transition zone,

and they „Seem to imply that the transverse movement of the

transpiration current must

gential than in a radial d

found to be the case in th

No. 467.] STUDY OF THE SALICACEE. SII

In transverse section the distribution, form, and compounding

of the vessels impart to the structure an appearance quite

similar to that found in the Rhamnacez. This very striking

resemblance is likely to result in confusion unless very careful

attention is given to details; and the likelihood of error from

this source is all the more probable when it is observed that

there is also a strong similarity of structural detail in radial

section. It is, however, not our purpose to discuss these resem-

Fic. 9.— Salix alba. Tang tial section. X 52.

blances at the present moment, since the essential differentia-

tions of the two families will be sufficiently emphasized by their

separate study. In the Salicacez the vessels give to the entire

Structure a high degree of porosity which is extended more or

less uniformly to the entire thickness of the gr owth — (Figs.

, 7). This general law is subject to variation in detail. Thus

812 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

in such types as Salir alba (Fig. 6), S. levigata, or S. longifolia

they are so abundant as to give the impression of predomi-

nance, an impression which is greatly strengthened in S. /asz-

andra where the vessels justify the description of ‘strongly

predominant throughout. The same law of distribution also

applies to the poplars, though with the very essential difference

that while in Salix there appears to be no very essential numeri-

cal reduction as between the initial zone and that which termin-

ates the growth ring (Fig. 6), in Populus on the contrary, the

initial zone usually shows a great increase in numbers with a more

or less gradual diminution toward the termination of growth for

the season (Fig. 7). This is fully expressed in such species as

P.alba, P. wislizeni, P.angustifolia, etc., but in P. monilifera

there seems to be a predominance which is fully maintained

until the region of the summer wood, when there is an abrupt

reduction.

The form of the vessel is typically oval in a radial direction

(Fig. 7), but this is sometimes varied to oblong as in Salix alba

(Fig. 6) or S. levigata, or to broadly oval as in Populus hetero-

phylla, or even to transversely oval as in P. alba. While in

general, the vessels are largest in the initial growth of the season,

the diminution in size toward the outer face

of the growth ring may proceed gradually

and without any very marked alteration as in

P. tremuloides (Fig. 7); they may become

abruptly smaller as in P. Sremonti, or they

may exhibit a graduated diminution as in 5.

uva-ursi.

One of the most striking features of the

vessels in the transverse section, is their

peculiar compounding, a feature also simi-

larly expressed in the Rhamnacex. Such

Fic, 10.—Pofulus tiremu- : : :

loides. Radial section CO™Mpounding in the Salicacex always occurs

showing the round or in i í : :

oval and distant bor- such manner as to give rise to radial series

"o (Figs. 6, 7) and in the various forms of com-

iain imi plexity thus arising, it constitutes within cer-

n : :

un "Imits, a valuable differential character for the various spe-

fies. Thus in Salir longifolia, S. discolor, S. uva-ursi, Populus

No. 467.] STUDY OF THE. SALICACEE. 813

alba, P. fremonti, P. pyramidalis, P. balsamifera, etc., the large,

oval vessels later become reduced in size, but they chiefly

remain single or become sparingly 2-compounded. In Salix

alba (Fig. 6), S. sessilifolia, or S. brachystachys, the vessels are

chiefly 1-, 2-, or rarely 3-compounded ; in S. migra, they are

rarely 8-compounded ; in .S. /asio/epis they are chiefly single

throughout; in S. Zancifolia they are rarely 4-compounded ; in

Populus fremonti they are rarely 5-compounded, and similar

variations are to be met with throughout the entire family,

always with the status of specific characters. While the gen-

eral facts are thus noted, it will be sufficient to refer to the

various diagnoses for an amplification of such details. It is

only occasionally that the vessels assume a definitely resinous

character. This is expressed among the species so far investi-

gated, only by the unusually resinous Sa/zr cordata, the vessels

of which are everywhere resinous.

Medullary Rays.—As in the Coniferales so in the Salicaceze,

the medullary ray presents some of the most

important of all the structural features for

diagnostic purposes. Their value is of both

a generic and a specific character. They are

expressed in both radial and tangential sec-

tions which it will be desirable to discuss

separately somewhat in detail.

In their tangential aspects the medullary

rays of the Salicacee may be described as

chiefly narrow; ı- or more rarely 2-seriate

in part. From this there is no essential de- bordered pits. x 350.

viation which applies to one genus more than

to the other, except in so far as variation is rather more charac-

teristic of Salix, and constancy more characteristic of Populus.

It may be said that broad rays, or rays with oval or transversely

oval cells, and 2-seriate rays are more common to the former

than to the latter. Such differences will be made sufficiently

clear by a comparison of Figs. 12 and 14, and Figs. 12 and 15.

One of the chief factors in the tangential section of the ray,

is the occurrence of ray cells of two kinds and the possibility

of distinguishing them from one another. These cells will be

814

THE AMERICAN NATURALIST.

[Vor. XXXIX.

referred to as (1) and (2), and their more detailed character-

istics will be discussed in connection with the

radial section. In the genus Populus, as clearly

shown in P. tremuloides (Figs. 12, 13), there is

no clearly defined distinction between the two

kinds of cells by means of which each may be

recognized beyond question. In Fig. 13, the

distinction is clear by reason of the distribution

of the resin and the special location of each kind

of cell. Thus the more resinous cells, 2, occu-

pying the central region, are of the first order

(1) while the less resinous cells, 4, occupying

the extremities of the ray, are of the second

order (2). This differentiation serves to illus-

trate the general law that the cells of the first

order are usually the more strongly resinous,

and that the less resinous cells

of the second order are chiefly

Fic. 12. — Populus . .

tremuloides. Tan- terminal unless also interspersed.

gential section of But such distinctions are not al-

the narrow medul- ü F

ways valid, even in the same spe-

‘œ Cies, since in Fig. 12, taken from

non-resin- 1

ous cells ofthe sec- the same section, the non-res-

ond order. X 350, . ^ š

3 7^ jnous terminal and interspersed

cells, 2, are probably all of the second order,

while the more resinous cells, a, are chiefly of

the first order. But the three resinous and ter-

minal cells of this figure involve considerable

doubt as to their precise character, inasmuch

as their positions would lead us to assume that

they must be of the second order in spite of

their resinous contents, à view which gains force

from what may sometimes be observed in radial

section.

In the genus Salix (Figs. 14 and 15), where

the structure is of a more

Character, the cells of the

usually all resinous,

decidedly resinous

medullary rays are

and this feature serves no

useful purpose in differentiations. We do find,

the second order.

X 350.

nevertheless,

No. 467.]

STUDY OF THE SALICACEE.

815

that in position and form, as also usually in size, there are dif-

ferential features of well defined value. Thus in Salix longi-

folia (Fig. 14) there is no room for hesitation

between the round or transversely oval cells, a,

of the first order constituting the bulk of the

structure, and the oblong narrow and terminal

Fic. 14.— Salix lon-

acter of the cells;

th. J Liz

- J

transversely oval

form of the cells of

cells being sharply

differentiated. X

350.

cells, 4, of the second order.

Or again in the same spe-

cies (Fig. 15), the same

difference appears in the

2-seriate form of the ray.

In low rays, the tendency

is for the cells of the first

order to be replaced by

those of the second order

as also shown in Fig. 15

on the right. From these

considerations it will be ob-

vious that the distinctness

with which these two forms

of cells appear in the tan-

gential section is of impor-

tance as a basis of generic

differentiation.

A. second factor of value

is to be found in the form

of the ray cell and its varia-

tions, In the genus Popu-

lus, the cells of two kinds

present little or no differ-

ence in form by which they

may be distinguished from one another.

This is especially true of P. balsamifera,

P. heterophylla, P. monilifera, etc., while

in P. tremuloides (Fig. 13), P. alba, P. pyramidalis, P.

&randidentata, etc.,

there is a somewhat obvious difference in

many cases which, taken in conjunction with other features,

Serves to bring such species into a separate group.

hus

TURALIST. [Vor. XXXIX.

816 THE AMERICAN NATURALIST. | [VoL

it will be found that where such differences exist, the is a d

second order are generally narrower and relatively hé : esc

longer. The cells of the first order are, as a rule, C K de iis

and oblong. Few exceptions to this occur (Fig. 15) t ies iee

may appear not only in the same species but also in bee

section. On the whole it may be said that Populus is ge Bn

characterized by narrow and oblong cells — the tendency Be

ovalor round form being of the nature of an exception. Re

genus Salix, on the contrary, the typical form of the ce ub

oval, round or even transversely oval (Figs. 14, 15), the o :

FB of narrow and oblong cells being of the nature of an excep

Fic, 16,.— Populus tremuloides. Radial

: inous

section of medullary rays showing the often resino!

character and Structural details in c

50.

ells of the first order, 2, and the second order, 5. X

an; nger

tion. The cells of the second order (2) are also much ee

and narrower than in Populus, differences which will be pod

explained by the radial. sections, so that considering these

à i eric

ences as a whole, they again afford a valuable element in gen

differentiations,

f specific value. These differences

prominently in the form and character of the

necessary to recognize cells of two kinds.

ray is composed of cylindrical cells several

are expressed most

cells whereby it is

Fundamentally the

No. 467.] STUDY OF THE SALICACEE. 817

times longer than broad, and either of uniform width throughout

or somewhat contracted at the ends. The terminal walls are

always more or less strongly pitted, but they exhibit somewhat

striking variations in this respect as between Salix (Fig. 17, a)

and Populus (Fig. 16, 2). The upper and lower walls are rather

thick and often strongly pitted, but in both of these respects

there is a marked difference between the two genera in such a

way that in Populus (Fig. 16, a) there is always a tendency to a

relatively thin wall with few pits, while in Salix (Fig. 17, æ) the

tendency is always toward a very thick and strongly pitted wall.

Such cells are generally resinous, more strongly so in Salix than

in Populus, and it is in them that resin is found when it may

[I z —

s EU, Des

ix hookeriana. Radial section of a medullary ray showing details in the struc-

ture of the cell walls: cells æ of the first order, and cells 4 of the second order, the latter

occupying a marginal position. X 350»

Fic. 17.— Sali

have been eliminated from all other parts of the ray. Such

cells I have designated as “cells of the first order” or (1).

They seem to be the more primitive parts of the structure, and

in this sense they are comparable with the parenchyma cells of

the gymnosperms (Penhallow, :04c). Their radial walls are

generally devoid of pits except that in a few instances I have

observed the occurrence of minute and simple pits opposite wood

cells, but so far as can be ascertained at the present time, this

feature possesses no special significance.

818 THE AMERICAN NATURALIST. (VoL. XXXIX.

Together with the cells of the first order, cells of a somewhat

and often wholly different characterappear. In the genus Popu-

lus, this differentiation is expressed with the least force, and it

is difficult or even impossible to distinguish between the two

except through certain special structural features of the radial

walls. Such cells are, generally speak-

ing the least resinous. To all such I

have applied the designation “cells of

the second order" or (2). An inspec-

tion of Fig. 16 taken from Populus

tremuloides, will show that there is es-

en — Populus tremuloides. sentially no distinction as to form and

section of cells of the sec-

ond order (2) showing oval pits on Structure, between cells of the first

bes walls opposite vessels. order g, and those of the second order,

6, and it is only when we study such

cells opposite vessels that the distinction becomes obvious. In

such regions cells (2) invariably show either oval (Fig. 18) or

quadrangular pits (Fig. 19) disposed in somewhat definite radial

series. Such pits and of the forms described, are characteristic

of the genus Populus, and from this there is no essential devia-

tion so far as our investigations have pro-

ceeded. These features make it clear

cdm Salix the case is very different, Ftc- 19.— Populus tremuloides.

ere we alw i Radial section of cells of the

teri ays find the Tay charac- . second order, (s) ehowiig quede

erized by the presence of cells which rangular pits on the lateral walls

opposite vessels. X 350-

ay that the cells become

and therefore high and narrow.

alix, and it has not been observed

It is this very strong difference in

differentiati

lon between the two kinds of cells as exposed in tan-

No. 467.] STUDY OF THE SALICACEE. 819

gential section. In addition, however, the cells (2) are always

characterized by their peculiar pits on the radial walls when

opposite vessels. These pits are

very rarely of the oval or quadran-

gular form presented by Populus.

On the other hand they are more

or less definitely angled and crowd-

ed as typically presented by Salix

alba (Fig. 20.) But such a form is

subject to very marked and sig-

nificant variation. Thus in such

types as S. sessilifolia, the individ-

angled pits on the lateral walls opposite

ual pits vary very greatly in size vessels- xa50.

and form, sometimes being greatly

reduced in size and multiplied in number, or again they diminish

in number and increase greatly in size (Fig. 21); and not infre-

quently — indeed we might say that very often, even in the same

species — there are all degrees of transition

exhibited from the angled pit of Salır alba

(Fig. 20) to typical scalariform structure in

S. sessilifolia (Fig. 22). Such transitional

forms are peculiar to Salix.

In the genus Populus the distribution of the

two kinds of cells is effected in such a way that

those of the first order occupy the central

region, while those of the second order occupy

the margins above and below (Fig. 16, 6, ^;

Fig. 13, 4, 6). Occasionally there is an inter-

Fic. 21. — Salix sessili-

folia. Radial section

showing a cell, a, of the

first order ( 1), and cells,

merging into scalari-

form structure. X 350.

ture, and the distinction of the two

without any difficulty in

spersal with the cells of the first order (Fig.

12, 6, 6), but in such cases, as already pointed

out, it is not always easy to distinguish the

two kinds of cells, especially in a tangential

section. In the genus Salix the same rela-

tion exists (Fig. 21, a), with the difference

that interspersal is a much more common fea-

kinds of cells may be made

any plane of section. The relations

thus indicated show that there is a tendency toward replace-

820 THE AMERICAN NATURALIST. | [Vor. XXXIX.

ment of the more primitive cells (1) by those (2) of a more

advanced and specialized functional value ; and this tendency is

carried to such an extent that in low rays the replacement is

often complete (Fig. 15). It is of interest from a developmental

point of view to note that this relation is precisely that which has

>" already been shown to exist among the higher

gymnosperms, with respect to the relative pre-

ponderance of parenchyma cells and ray tra-

cheids, and such a comparison goes far to prove,

especially in connection with: other relations to

be described immediately, that the cells of the

second order are of the higher type of develop-

ment.

The features thus described for the radial sec-

tion of the medullary ray, are of both generic

and specific value as will be seen from the diag-

noses given, but it should be pointed out that

the recognition of two forms of cells in the medullary ray of the

Salicacez is exactly parallel with what has already been noted

as characteristic of the Coniferales (Penhallow, :04c), though

with one important difference. In the gymnosperms the ray

contains in its more primitive condition, parenchyma cells only,

although these later become differentiated into two specialized

forms. As a whole, these are equivalent, from the standpoint

of development and functional value, to cells of the first order

in the Salicaceze. But in all the higher Coniferales the ray also

contains specialized ray tracheids which manifestly provide greater

freedom in radial circulation, and as already shown elsewhere,

(Penhallow, : 04c), such development is in direct response to

the requirements of a higher type of organization. No such tra-

cheids occur in the rays of the Salicaceze, but they are exactly

represented in a functional sense by the cells of the second

order (2), which also serve as evidence of a higher type of

organization.

* hes a Sin si present intention to discuss the phylogeny

rc eiu x din and to establish its relative position

ital ct > ution, It is desirable to indicate that ‘the

€ evidence so far collected — geographical,

sel. X 350.

No. 467.) STUDY OF THE SALICACEE. 821

geological, anatomical— is all in one direction, and that is to

show that the genus Populus is essentially the more primitive

member of the family, and that it is the genus through which

we must probably seek connection with ancestral forms.

It only remains to point out that with respect to a delimita-

tion of species and varieties, the rule adopted for the gymno-

sperms (Penhallow, :04c) applies with equal force here, to the

effect that varieties have no proper status on anatomical grounds,

and what are designated as such on the basis of external mor-

. phology must be regarded as species from the standpoint of the

present studies.

SALICACEZE

Transverse.— Growth rings usually devoid of recognizable differentiation

of spring and summer wood, the outer limits being defined by a usually

resinous wood parenchyma of radially narrower cells, forming a zone

upwards of three elements thick. Wood cells variable, hexagonal, and usu-

ally not in obvious radial rows. Vessels numerous throughout, often pre-

dominant, and more or less radially compounded.

Radial.— Medullary rays composed of two kinds of cells, 7. e., those with-

out (1) and those with (2) pits on the lateral walls opposite vessels. Vessels

commonly with thyloses, their radial walls with numerous, multiseriate,

usually localized, oval, round, or hexagonal bordered pits.

Tangential.— Medullary rays chiefly narrow ; 1- or more rarely 2-seriate

in part. Vessels with numerous, multiseriate, hexagonal, bordered pits

throughout.

1. Populus.

Radial— Ray cells of two kinds but presenting no essential distinction

as to length, height, and thickness of the walls ; the pits on the lateral walls

of cells (2) more definitely rounded, oval or sparingly angled, when they

become quadrangular and lie in radial series, never merging into scalari-

form structure. o

Tangential The two kinds of ray cells not clearly distinguishable.

Synopsis OF SPECIES.

Ray cells (2) (tangential) more or less distinguishable

by differences in

height, breadth, and less resinous contents.

822 THE AMERICAN NATURALIST. | (Vor. XXXIX.

Rays (tangential) 2-seriate in part.

Ray cells (1) somewhat variable, oblong, narrow, or broader and oval;

unequal.

Vessels (transverse) broad, oval, 1- to 3-, more rarely 5-compounded.

I. P. fremontt.

Rays (tangential) strictly 1-seriate.

Ray cells (1) (tangential) uniform, narrow, oblong, equal, but occa-

sional rays with broader, oval, and somewhat variable, unequal

cells.

Vessels (transverse) broad, oval, or transversely oval, I- to 2- or

rarely 4-compounded. ; 3. Fam

Vessels (transverse) broadly oval, 1- to 4- or rarely 7-compounded.

P. tremuloides.

Ray cells (1) (tangential) uniform, narrowly oblong, and equal, but in

different rays sometimes broadly oblong.

Vessels (transverse) very numerous, broad, 1- to 3- or rarely 4-com-

pounded. . : I : ; 5. P. pyramidalis.

Vessels (transverse) numerous, much smaller toward the outer face

of the growth ring, 1- to 4- or rarely 5-compounded.

. P. grandidentata.

Ray cells (2) (tangential) not distinguishable from (1).

Rays (tangential) all strictly 1-seriate.

Rays (tangential) with diminishing terminal width.

Vessels (transverse) at first predominant, gradually diminishing in

size and number, 1- to 3-, rarely 4- to 5-compounded.

P. wislizeni.

Rays (tangential) of uniform width throughout.

essels (transverse) numerous, oval, r- to 4- or rarely 5-com-

pounded. . : : : : i P. balsamifera.

Vessels (transverse) at first predominant, gradually diminishing in

Size and number; 1- to 4^ rarely 6-compounded. |

. P. angustifolia.

Vessels (transverse) numerous throughout, naar pe i the

Outer portions of the growth ring; 1- to 4-compounded.

10. P. trichocarpa.

ring sometimes 3-compounded. PUS

Rays (tangential) 2-seriate in ae * . 11. P. heterophy

m m uniform in width throughout

region of the Ait broadly oval, abruptly fewer in the

er wood, chiefly single, or less frequently

2- to 3-compounded. : : j P moaier.

No. 467.] STUDY OF THE SALICACEE. 823

L. P. fremonti Wats.

Transverse-— Growth rings very broad, the limiting zone of wood

parenchyma devoid of resin, I to 2 cells thick. Vessels large, broad, oval,

becoming somewhat abruptly smaller toward the outer limits of the growth

-ring ; I- to 3-, more rarely 5-compounded. Rays numerous, sparingly resin-

ous, one cell wide, distant upwards of 12 rows of wood cells.

Radial.— Ray cells (1), the upper and lower walls thin and finely pitted ;

the terminal walls straight or curved and finely pitted. Cells (2), the upper

and lower and terminal walls thin, very finely and obscurely pitted ; the

pits on the lateral walls forming a coarse, sieve-plate structure. :

Tangential— Rays medium to high, numerous, ı-seriate, very sparingly

resinous, sometimes 2-seriate. The cells (1) somewhat variable, oblong and

narrow or broader and oval, unequal. Cells (2) not conspicuously different

but the terminal ones sometimes higher, the interspersed ones sometimes

narrow.

2. P. monilifera Ait.

Transverse.— Growth rings medium to narrow, the limiting wood paren-

chyma devoid of resin, in 2 to 3 rows. Vessels numerous throughout,

broadly oval, becoming rather abruptly fewer at the outer limits of the ring,

chiefly single, or less frequently 2- to 3-compounded. Medullary rays

prominent, numerous, very sparingly resinous, and distant upwards of 6

rows of wood cells, one cell wide.

Radial— Rays sparingly resinous, the cells contracted at the entis.

Cells (1), the upper and lower walls rather thick, unequal, and finely pitted ;

the terminal walls thick, straight or curved, and finely pitted. Cells (2), the

upper and lower walls thick and finely though remotely pitted ; the terminal

walls often strongly curved, thick, and finely pitted; the pits on the lateral

walls round, oval, or sparingly angled, in radial series.

Tangential.— Medullary rays very numerous, low to high, very sparingly

resinous, I-seriate or sometimes 2-seriate in part. Cells (1), uniform in the

same ray and oblong, equal but in different rays ranging from very nar-

rowly oblong to rather broadly oblong. Cells (2) not distinguishable.

3. P. alba (Linn.).

Transverse. — Growth rings narrow, uniform, the limiting wood paren

chyma very sparingly if at all resinous, in I, sometimes 2 = gg

rays prominent, somewhat resinous, I cell wide, distant upwards 0 r

sometimes 10 rows of cells. Vessels broad, oval, or transversely A

first predominant, gradually diminishing in size and number outwardly ; 1-

to 2-, or more rarely 4-compo :

824 THE AMERICAN NATURALIST. [Vor. XXXIX.

Radial. — Medullary rays very sparingly resinous. Cells (1), the upper

and lower walls rather thick, finely but strongly pitted ; the terminal walls

straight, often diagonal, finely pitted ; equal to about 6 wood cells. straight.

Cells (2), the upper and lower walls somewhat thinner and not obviously

pitted ; the terminal walls conspicuously though finely pitted; the pits on

the lateral walls hexagonal, forming a coarse, sieve-plate structure; some-

what variable in height and sometimes rather short.

Tangential. — Rays numerous, very sparingly resinous, medium, I.seri-

ate. Cells (1) chiefly uniform, narrow, oblong, and equal, but occasionally

rays with broader, oval, and somewhat variable and unequal cells. Cells

(2, uniform, narrow, somewhat variable, the terminal ones often much

higher.

4. P. tremuloides Michx.

Transverse. — Growth rings broad, uniform; the limiting wood paren-

chyma sparingly resinous, in 1 to 2 rows. Vessels at first medium, becom-

ing larger and finally smaller toward the outer limits of the growth ring,

broadly oval, 1- to 4- or more rarely 7-compounded. Medullary rays om

numerous, one cell wide, sparingly resinous, distant upwards of 10 rows of

wood cells.

Radial. — Ray cells sparingly resinous, straight. Cells (1), the upper

and lower walls thin, and finely pitted ; the terminal walls thin, straight

or curved, and rarely pitted. Cells (2), the upper and lower walls thin

and sparingly pitted; the terminal walls rarely pitted, often curved ; the

pits on the lateral walls round, chiefly in radial series.

Tangential.— Rays numerous, resinous, low to high, r-seriate. The cells

(1), uniform, narrowly oblong and equal, low rays sometimes showing broader

and oval cells throughout. Cells (2) not readily distinguishable, but in low

rays sometimes twice as high and less resinous.

5. P. pyramidalis Ait.

ring; 1- `

5s in A to A more rarely 4-compounded. Medullary rays prominent, nar-

: ‚one cell wide, numerous, and distant upwards of 7,more rarely 10

ows of cells ; somewhat resinous.

Radial. — Medull |

finely pitted. Cells and strongly pitted throughout ; the terminal walls

ri CO nn Muf pitted ; the pits on the lateral walls round

or sparingly angled

No. 467.] STUDY OF THE SALICACEE. | 825

Tangential.— Rays very numerous, resinous, medium to high, narrow,

I-seriate. The cells (1) chiefly uniform, rather narrowly oblong and equal in

the same ray, but in different rays sometimes varying to broadly oblong.

Cells (2) not readily distinguishable except by their less resinous contents

and somewhat more variable form and unequal size, usually giving the ray

a diminishing terminal width.

6. P. grandidentata Michx.

Transverse. — Growth rings narrow, uniform ; the limiting wood paren-

chyma with thin-walled cells in 1 to 3 rows, often very resinous. Vessels

numerous throughout the growth ring but usually much smaller near the

outer limits of the ring; 1-to 4- more rarely 5-compounded. Medullary

rays prominent but narrow, ı cell wide and distant upwards of 10 or some-

times 12 rows of cells ; somewhat resinous.

Radial.— Ray cells straight. Cells (1), the upper and lower walls thin

and entire or obscurely pitted ; the terminal walls thin, straight, or curved,

finely pitted. Cells (2), the upper and lower walls rather thin and not obvi-

ously pitted; the terminal walls often strongly curved, rather thick, and

conspicuously pitted ; the pits on the lateral walls oval or round in radial

series. Isodiametric, thin-walled idioblasts, containing each a single crystal

of calcium oxalate of the quadratic system, often form extensive, longitu-

dinal series adjacent to vessels.

Tangential. — Medullary rays numerous, narrow and high, strictly

I-seriate, resinous. The cells ( 1) chiefly uniform in the same ray and nar-

rowly oblong, equal; but between different rays varying to oblong. Cells

(2) not very readily distinguishable, but usually less resinous and often

variable from narrowly oblong to oval so as to give the same ray a con-

spicuously unequal width.

7. P. wislizent Watson.

Transverse. — Growth rings broad ; the limiting wood parenchyma spar-

ingly resinous in 1 to 3 rows. Vessels at first, predominant, gradually

diminishing in size and number toward the outer limits of the growth

ring ; 1- to 3-, more rarely 4- to 5-compounded. Medullary rays prominent,

narrow, one cell wide, distant upwards of 10 rows of cells, numerous,

sparingly resinous. i

Rie — Ray cells straight, equal to about 14 wood cells but becoming

very short toward the outer limits of the growth ring. Cells (1), the upper

and lower and terminal walls rather thin, rather obscurely and finely pitted ;

the pits on all the walls becoming much more prominent in the outer region

of the growth ring. Cells (2), the upper, lower, and termina walls not et

different from (1); the pits on the lateral walls forming a coarse sieve-pla

Structure.

826 THE AMERICAN NATURALIST. (VoL. XXXIX.

Tangential. — Rays numerous, narrow, medium to high, sparingly resin-

ous, I-seriate. Cells (1) uniform, narrowly oblong, and equal, sometimes

becoming broader and oval in the central tract so as to form tapering

extremities to the ray. Cells (2) not readily distinguishable but uniform,

narrow, oblong, and equal.

8. P. balsamifera Linn.

Transverse. — Growth rings medium, uniform ; the limiting wood paren-

chyma conspicuously resinous, of one or sometimes two rows of celis.

Vessels numerous, oval, becoming gradually smaller toward the outer limits

of the growth ring ; 1- to 4- or more rarely 5-compounded. Medullary rays

numerous, prominent, resinous, one cell wide, and distant upwards of 8

rows of cells.

Radial. — Rays strongly resinous, the cells straight. Cells (1), the upper

and lower walls thin and finely pitted; the terminal walls straight or

curved, obscurely if at all pitted. Cells (2), the upper, lower, and terminal

walls thin and obscurely if at all pitted ; the pits on the lateral walls round,

in radial series,

Tangential, — Rays very numerous, strongly resinous, low to high,

I-seriate. Cells (1) uniform in the same ray and oblong, but varying

between different rays from narrowly oblong to broadly oblong, equal.

Cells (2) not distinguishable except by their less resinous contents.

9. P. angustifolia James.

Transverse.— Growth rings broad ; the limiting wood parenchyma con-

spicuously resinous, usually upwards of 3 rows of cells thick. Vessels

at first somewhat predominant, gradually diminishing in number and finally

its of the growth ring where they are very much

> ! cell wide, distant upwards of 9 rows of cells.

Cells (1), the upper and lower walls

d strongly pitted ; the terminal walls rather thick

and strongly pitted. Cells (2), the upper and lower walls sparingly pitted ;

in and sparingly if at all pitted ; the pits on the lateral

radially seriate.

ary rays numerous and very variable, low to high,

^ie. Cells (1) uniform in the same ray and chiefly

equal, but in some rays becoming twice as broad

not distinguishable.

walls round or oval and

Tangential — Medull

narrow, resinous, I-seri

very narrowly oblong,

nd oblong. Cells (2)

10. P. trichocarpa Torr. & Gr.

ee Growth rings very broad ; the limiting wood parenchyma

Sparingly resinous. Vessels numerous throughout, becoming abruptly

No. 467.] STUDY OF THE SALICACEE. 827

smaller in the outer limits of the growth ring; 1-to 4-compounded. Medul-

lary rays narrow but rather prominent and somewhat resinous ; one cell

wide, numerous and distant upwards of 12 rows of cells.

Radial— Ray cells straight. Cells (1), the upper and lower walls thin

and not obviously pitted except in the outer limits of the growth ring; the

terminal walls straight or curved, and finely pitted. Cells (2), the upper

and lower walls usually thick and more or less strongly pitted ; the terminal

walls rather thick and strongly pitted ; the lateral walls with round or spar-

ingly angled and radially seriate pits.

Tangential.— Rays rather numerous, resinous, high, narrow, strictly 1-

seriate. Cells (1) chiefly uniform, narrowly oblong and equal, in a few rays

becoming broader and oblong, somewhat unequal. Cells (2) not readily

distinguishable.

11. P. heterophylla Linn.

Transverse.— Growth rings medium, rather uniform ; the limiting wood

parenchyma not very prominent, usually one cell thick and often forming a

discontinuous zone. Vessels numerous and large, oval or round, often in

series continuous and compounded with those of the previous year, dimin-

ishing steadily in size toward the outer face of the growth ring ; chiefly

single but often 2-, or on the outer face of the growth ring sometimes 3-

compounded. Medullary rays not very prominent, 1 cell wide, rather

numerous and distant upwards of 6 or more rarely 10 rows of cells.

Radial.— Medullary rays non-resinous. : Cells (1), the upper and lower

walls, as also the terminal walls, usually rather thick and strongly pitted.

Cells (2), the upper and lower walls somewhat thinner, less strongly pitted ;

the terminal walls strongly pitted; the lateral walls with round, oval, or

sparingly angled pits.

Tangential.— Medullary rays numerous, rather high, non-resinous, nar-

row, 1 cell wide. Cells (1) chiefly uniform in the same ray, oblong and

equal, but between different rays varying from narrowly oblong to rather

broadly oblong. Cells (2) not distinguishable from the first.

2. Salix.

Radial.— Ray cells (1) usually low and thick-walled, several times

longer than high ; the upper and lower and terminal walls commonly pitted.

Cells (2) often thin-walled, marginal, and interspersed, commonly predom-

inant, very variable, short, and often several times higher than long ; the

pits on the lateral walls more definitely angled, forming more extensive and

finer sieve-plates, and sometimes merging into definite scalariform struc-

ture.

Tangential.— Ray cells clearly distinguishable as of two kinds.

828 THE AMERICAN NATURALIST. (VoL. XXXIX.

SYNOPSIS OF SPECIES.

Pits on the lateral walls of the ray cells (2) angled or oval and merging

into an open, scalariform structure. !

, Resinous wood parenchyma prominent throughout in association with the

vessels. :

Rays (tangential) narrow, the cells (1) uniform, narrow and oblong.

Vessels oval, 1- to 2- or more rarely 3-compounded.

13. S. sessilifolia.

Resinous wood parenchyma confined to the outer limits of the grow

ring. :

Rays (tangential) numerous, resinous, and chiefly narrow. Cells (1)

somewhat variable, chiefly oblong and narrow, more rarely oval,

more or less conspicuously unequal.

Vessels broad (transverse), oval, 1- to 4- or finally 4- to 5-com-

nded. i à : : ; 14. S. amygdaloides.

Rays (tangential) resinous, numerous, broader; cells (1) variable,

oblong to broadly oval and conspicuously unequal.

Vessels (transverse) predominant throughout, oval, 2- to 4- or finally

5-compounded. : oa I : z 15. S. discolor.

Rays (tangential) broad, more or less 2-seriate ; the cells (1) variable,

oval to oblong and conspicuously unequal.

Vessels (transverse) chiefly single throughout, but sparingly 2- to y

compounded. : ; : i j S. lasiolepis.

Pits on the lateral walls of the ray cells (2) hexagonal or quadrangular,

forming coarse sieve-plates, but devoid of scalariform structure.

Resinous wood parenchyma conspicuous throughout the growth ring.

Resinous wood parenchyma confined to the vessels and the limiting

zone.

Rays (tangential) numerous, resinous, 2-seriate in part; the cells

(1) variable, narrowly to broadly oval, or round, or even pn

ish, very unequal. . . 10. S. longifolia.

Resinous wood parenchyma numerous and often forming definite

tracts

Rays (tangential) very numerous, narrow ; cells (1) uniform, oval, and

chiefly equal NENNEN. Q1 X 4 LS o

Resinous wood parenchyma confined to the limiting zone.

Rays (tangential) narrow, I-seriate. 2

Ray cells (1) variable, oblong, narrow or more often broadly oval or

squarish, unequal.

Vessels (transverse)

) and n

Ray cells (1) uniform in the sa

rays,

at first broadly oval; 1- to 3- or finally —

arrow. : efie, . ^ €

mé ray but variable between different

narrowly oblong to oblong, chiefly equal.

No. 467.] STUDY OF THE SALICACEE. 829

Vessels (transverse) strongly predominant throughout, 2- to 3- or

more rarely 4-compounded. ; ; i 8.45. alba.

Ray cells (1) somewhat variable, chiefly oblong or sometimes ,

broadly oval; chiefly equal.

Vessels (transverse) strongly predominant, 2- to 5-compounded.

S. lasiandra.

Ray cells (1) chiefly uniform and oblong, sometimes oval; unequal,

often twice as broad or twice as high.

Vessels (transverse) large, strongly predominant, 2- to 3- or rarely

4-compounded. . ; A ‘ ; S. lancifolia.

Ray cells (1) uniform, oblong, chiefly equal.

Vessels (transverse) predominant, at first large, chiefly simple but

2- or very sparingly 3-compounded. 8. S. brachystachys.

Ray cells (1) narrow, chiefly uniform, oval or more generally oblong,

equal

qual.

Vessels (transverse) uniform in size and number throughout,

except at the outer limits of the growth ring where they

abruptly diminish in size; chiefly 1- often 2- to 3-com-

pounded. . : : i : : 9. S. scouleriana.

Rays (tangential) broader, more or less 2-seriate.

Ray cells (1) uniform in the same ray, variable between different

rays, oval or squarish, broad, unequal.

Vessels (transverse) predominant, 2- to 3- or more rarely 5-com-

pounded. : : ; ; : ; 1. S. Zevigata.

Ray cells (1) uniform, oval, narrow, chiefly equal.

Vessels (transverse) single or somewhat 2- to 3-compounded.

2. S. hookeriana.

Ray cells (1) thin-walled, uniform, oblong, narrowly oval, equal.

Vessels (transverse) not predominant, I- to 4-compounded, con-

spicuously fewer toward the outer limits of the growth ring.

3. S. uva-ursi.

1. S. levigata Bebb.

Transverse —Growth rings very broad; the limiting wood parenchyma

about 3 cells thick, sparingly resinous. Vessels predominant throughout,

at first rather large, radially oblong and very gradually reduced in size to

the outer limits of the growth ring where they are about 1 the original

dimensions ; 2- to 3- more rarely 5-radially compounded. Medullary rays

numerous, resinous, prominent, 1 cell wide, distant upwards of 6 rows of

celis.

Radial Rays resinous. Cells (1), the upper and lower walls thin and

not pitted ; the terminal walls finely pitted. Cells (2) sometimes predomi-

nant; the upper and lower walls thin and not pitted ; the terminal walls finely

pitted ; the pits on the lateral walls forming a coarse sieve-plate structure.

830 THE AMERICAN NATURALIST. (Vor. XXXIX.

Tangential— Rays very numerous, medium to rather broad, 2-seriate in

part, resinous. Cells (1) uniform in the same ray but variable in different

rays, oval or squarish, unequal. Cells (2) uniform and narrowly oblong,

strongly unequal, often several times higher than broad.

2. .S. hookeriana Burr.

Transverse.— Growth rings very broad ; the limiting wood parenchyma

composed of rather distant and resinous cells. Vessels rather numerous,

single or somewhat 2- to 3-compounded, oval, very gradually diminishing in

size to the outer limits of the growth ring where they are 1 to 1 the diameter

of the first. Medullary rays numerous, slightly resinous, 1 cell wide, dis-

tant upwards of 8 rows of cells.

Radial— Rays rather sparingly resinous. Cells (1) more resinous ; the

upper and lower walls thick and very unequally, often sparingly pitted ; the

terminal walls rather strongly though finely pitted. Cells (2) less resinous,

the upper and lower walls rather thin and devoid of pits; the terminal

walls strongly and finely pitted; the pits on the lateral walls minute, simple

and often slitlike when opposite wood cells, but forming a coarse sieve-

plate structure opposite vessels.

Tangential— Rays numerous, resinous, sometimes 2-seriate in part, low

to high, narrow. Cells (1) rather uniform and oval, chiefly equal. Cells (2)

variable, narrowly oblong and more or less conspicuously unequal, rather

thin-walled.

3. S. uva-ursi Pursh.

Transverse. — Growth rings narrow, variable, eccentric; the limiting

wood parenchyma rather resinous and prominent; the wood cells thin-

walled and squarish throughout with no obvious distinction of spring and

summer wood. Vessels not predominant, 1- to 4-compounded and conspic-

uously few toward the outer face of the growth ring. Medullary rays 1 cell

wide, very sparingly resinous, not prominent, distant upwards of 6 rows of

wood cells.

Radial. — Medullary rays sparingly resinous. Cells (1), the upper and

lower walls usually thin and not obviously pitted ; the terminal walls some-

what strongly pitted. Cells (2), the upper and lower walls thin and not

obviously pitted; the terminal walls finely pitted ; the pits on the lateral

walls forming a strong sieve-plate structure ; Strongly predominant.

Ti angential. — Medullary rays low to medium, very narrow, sparingly

resinous, 2-seriate in part, the cells chiefly thin-walled throughout. Cells (1)

uniform, oblong, to narrowly oval; equal. Cells (2) uniform, narrowly oblong,

unequal, and often several times higher than broad ; usually predominant

and often excluding (1).

No. 467.] STUDY OF THE SALICACEE. 831

4. S. nigra Marsh.

Transverse.— Growth rings broad, the inner region of the growth ring

usually more dense; the limiting wood parenchyma sparingly resinous, in

1 to 2 rows of cells. Vessels numerous, large, rather broad, and oval, grad-

ually diminishing in size and number toward the outer region of the growth

ring and finally becoming few, narrow, and rather small; 1- to 3-com-

pounded or in the outer portions of the ring often 8-compounded and nar-

row. Rays rather numerous, not very prominent, very sparingly resinous,

1 cell wide, and distant upwards of 8 rows of wood cells.

Radial.— Medullary rays locally resinous. Cells (1), the upper and lower

walls rather thin and usually not obviously pitted ; the terminal walls chiefly

thin and devoid of pits. Cells (2), the upper and lower walls thin and devoid

of pits; the terminal walls strongly but finely pitted ; the pits on the lateral

walls forming a strong sieve-plate structure.

Tangential.— Rays very numerous, medium, sparingly resinous, ı-seriate,

and broad. Cells (1), variable, unequal, oblong and narrow or more often

broad and oval or squarish; unequal. Cells (2) less resinous, variable but

chiefly narrowly oblong, unequal, and differing in both height and width.

5. S. alba Linn.

Transverse.— Growth rings very broad, the limiting wood parenchyma

I to 2 cells thick, resinous. Vessels strongly predominant throughout ;

large, oval, often oblong, chiefly single but often 2- to 3- or more rarely 4-

compounded ; not diminishing sensibly toward the outer face of the growth

ring. Medullary rays numerous, somewhat resinous, I cell wide, distant

upwards of 8 rows of wood cells.

Radial.— Rays sparingly resinous. Cells (1), the upper and lower walls

thick, and strongly pitted throughout, the terminal walls generally curved

and strongly pitted. Cells (2), the upper and lower and terminal walls

strongly pitted; the pits on the lateral walls forming a strong sieve-plate

structure; often approximating in height and general character to cells (1).

Tangential.— Rays resinous, numerous, narrow, medium. Cells (1) uni-

form in the same ray but variable in different rays, and ranging from nar-

rowly oblong to oblong; chiefly equal. Cells (2) less resinous, uniform but

unequal, differing greatly in height.

6. S. lasiandra Benth.

Transverse.— Growth rings broad; the limiting zone of un.

chyma continuous, conspicuous and resinous, I to 2 cells thick. —

strongly predominant, radially and somewhat tangentially 2- to 5com

pounded, steadily diminishing in size to the outer limits of the growth ring

832 THE AMERICAN NATURALIST. [Vor. XXXIX.

where they are reduced to 1 or 1 the first size. Rays somewhat resinous,

prominent, 1 cell wide, distant upwards of 6 rows of wood cells. i

Radial— Rays somewhat resinous. Cells (1), the upper and lower walls

rather thick and often strongly pitted ; the terminal walls thick and strongly

though finely pitted. Cells (2) more resinous, often predominant; a

upper and lower walls thin and not pitted; the terminal walls, thicker ant

Strongly though finely pitted, the pits on the lateral walls forming a promi-

nent sieve-plate structure.

Tangential. — Rays numerous, resinous, narrow, chiefly medium, Cells

(1) somewhat variable, chiefly oblong or again broadly oval; chiefly equal.

Cells (2) uniform and narrowly oblong; very unequal and often several

times higher than broad.

7. S. lancifolia Anderss.

Transverse. — Growth rings broad ; the limiting wood parenchyma resin-

ous and prominent. Vessels rather large and strongly predominant through-

out, radially oval and 2- to 3- rarely 4-compounded ; diminishing very gradu-

ally in size to the outer limits of the growth ring where they are about two

thirds the first diameter,

Cells (1), the upper and lower walls thick and

unequally though often strongly pitted; the terminal walls thick and

strongly though finely Pitted. ^ Cells (2), the upper and lower and ter-

minal walls thick and strongly pitted ; the pits on the lateral walls forming

a Coarse sieve-plate structure.

Tangential.— Rays numerous, resinous, narrow, medium. Cells (1) chiefly

uniform and oblong, but varying somewhat from oval to oblong ; unequal

and often twice as broad or twice as high. Cells (2) much less resinous,

uniform, narrowly oblong, unequal.

8 S. brachystachys Benth.

Radial. — Rays non-resinous.

thin and not obviously pitted ; th

(2), the upper and lower walls thi

Cells (1), the upper.and lower walls rather

e terminal walls with very fine pits. Cells

n and not pitted; the terminal walls some-

No. 467.] STUDY OF THE SALICACEE. 833

what thicker and very finely pitted ; the pits on the lateral walls forming a

coarse, sieve-plate structure.

Tangential.— Rays numerous, narrow, low to rather high, somewhat res-

inous. Cells (1) uniform, oblong, chiefly equal. Cells (2) uniform, narrowly

oblong, very unequal, and often several times higher than broad.

9. S. scouleriana Bebb.

Transverse.— Growth rings medium ; the limiting zone of wood paren-

chyma somewhat resinous, 1 to 3 cells thick. Vessels somewhat uniform in

size and number throughout, except at the outer limits of the growth ring

where they abruptly diminish in size ; oval, rather broad, chiefly 1-, but fre-

quently 2- to 3- more rarely 4-compounded. .Medullary rays numerous, prom-

inent, resinous, 1 cell wide, and distant upwards of 8 rows of cells.

Radial.— Medullary rays resinous. Cells (1), the upper and lower and ter-

minal walls thick and strongly pitted throughout. Cells (2), the upper and

lower and terminal walls rather thick and strongly pitted; the pits on the

lateral walls forming a prominent sieve-plate structure.

Tangential— Rays numerous, resinous, medium, narrow, I-seriate. Cells

(1) narrow, chiefly uniform, oval or more generally oblong, equal. Cells (2)

uniform, narrowly oblong but very unequal, and often several times higher.

10. S. longifolia Muhl.

Transverse— Growth rings usually very broad but very variable and

sometimes very narrow. Wood parenchyma cells numerous, very resinous,

and associated with the vessels as well as forming an open zone on the

outer face of the growth ring. Vessels predominant throughout, especially

in the earlier portions of the growth ring; at first rather large, oval, and

1- to 3-compounded, later somewhat reduced, round, and simple or some-

what 2-compounded. Medullary rays numerous, resinous, 1 to 2 cells

wide, distant upwards of 6, or more rarely 10 rows of wood cells.

Radial.— Medullary rays resinous. Cells (1), the upper and lower walls

sparingly pitted, the terminal walls strongly but finely pitted. Cells (2),

the upper and lower walls rather thick but not obviously pitted, the termi-

nal walls very strongly pitted ; the pits on the lateral walls forming a coarse

sieve-plate structure.

Tangential. — Rays very numerous, resinous, 2-serlate in part. Cells

(1) very variable, from narrowly to broadly oval, or round, or even —

ish, very unequal. Cells (2) uniform, narrowly oblong but unequal an

generally with thinner walls.

| 11. S. cordata Muhl.

Transverse — Growth rings broad, terminated by 2 to 3 rows of 2a

flattened, rectangular wood cells ; the limiting wood parenchyma prominen

834 THE AMERICAN NATURALIST. Vor. XXXIX.

resinous ; the structure rather dense throughout. Vessels not predominant ;

at first very numerous and very resinous, quickly diminishing in number

and thence constantly diminishing in size and number, and always distant,

to the outer face of the growth ring; rather small, oval, sparingly 2- or

more rarely upwards of 4-compounded ; everywhere numerous. Resinous

wood parenchyma cells numerous throughout ; associated with vessels and

scattering throughout the growth ring, often forming more or less definite

and extensive tracts. Medullary rays very numerous, resinous, I cell wide,

distant upwards of 10 rows of cells.

Radial.— Ray cells very resinous. Cells (1), the terminal walls very

thick and very strongly pitted ; the upper and lower walls sparingly if at all

pitted except in the later portions of the growth ring. Cells (2), often

predominant ; the upper and lower walls thin and not pitted except in the

later portions of the growth ring; the terminal walls strongly pitted ; the

pits on the lateral walls forming a coarse sieve-plate structure.

Tangential.— Rays very numerous, medium, narrow, resinous. Cells (1)

uniform, oval, and chiefly equal throughout. Cells (2) variable, oblong,

often very narrow and unequal, often several times higher than broad, the

walls commonly thinner.

12. S. lasiolepis Torr.

Transverse— Growth rings broad; the limiting wood parenchyma 1 to

4 cells thick, sparingly resinous. Vessels at first not strongly predominant ;

oval or oblong, steadily diminishing in size and finally much reduced ;

chiefly single throughout, but sparingly 2- to 3-compounded. Medullary

rays numerous, locally resinous, 1 to 2 cells wide, distant upwards of 6 rows

of wood cells. |

Radial. — Medullary rays resinous. Cells (1), the upper and lower walls

sparingly and unequally pitted, often devoid of pits; the terminal walls

strongly but finely pitted. Cells (2), the upper and lower walls chiefly

rather thin and devoid of pits; the terminal walls strongly pitted ; the pits

on the lateral walls forming a coarse sieve-plate structure often coalescing

into a Coarse scalariform structure.

Tangential. — Rays very numerous, medium, resinous, I- to 2-seriate.

Cells (1) variable, oval to oblong, and conspicuously unequal. Cells (2)

less resinous, variable, and unequal, often high.

13. S. sessilifolia Nutt.

Transverse — Growth rings broad ; the limiting wood parenchyma 1 to

2 rows of cells broad, occasionally resinous and confluent with resinous

wood parenchyma in the adjacent spring wood. Vessels numerous and

predominant throughout ; radially oval and variable in size ; I- to 2-, more

No. 467] STUDY OF THE SALICACEE. Ss

rarely 3-compounded, especially at the outer limits of the growth ring where

they are diminished to 1 size. Resinous wood parenchyma more or less

prominent throughout the growth ring in association with the vessels.

Medullary rays numerous, rather prominent and resinous, 1 cell wide, dis-

tant upwards of 10 rows of wood cells.

Radial.— Rays somewhat resinous. Cells (1), the upper and lower and

terminal walls strongly though rather finely pitted throughout, more resin-

ous than the next. Cells (2) less resinous, often predominant ; the upper

and lower walls rather thin and sparingly pitted; the terminal walls strongly

though finely pitted; the pits on the lateral walls variable, hexagonal, and

forming a coarse, sieve-plate structure which more commonly becomes an

open scalariform structure through transitional forms.

Tangential.— Rays sparingly resinous, low to medium, numerous, nar-

row. Cells (1) chiefly uniform, narrow, oblong, equal. Cells (2) uniform,

narrowly oblong, very unequal and often several times higher than broad,

less resinous than (1).

14. S. amygdaloides Anderss.

Transverse.— Growth rings broad; the limiting zone of wood paren-

chyma 1 to 4 cells thick and not obviously resinous. Vessels broad, oval,

at first predominant, soon diminishing slightly in size and number toward

the outer face of the growth ring where they are again somewhat abruptly

reduced in size; at first oval, rather broad, and 1- to 4-compounded ; finally

much reduced in size and width and becoming 4- to 5-compounded.

Medullary rays numerous, 1 cell wide, not resinous, and distant upwards of

16 rows of wood cells.

Radial.— Medullary rays more or less resinous. Cells (1), the upper,

lower, and terminal walls rather thin and finely, the first obscurely if at all

pitted. Cells (2), the upper and lower and terminal walls rather thin, |

last finely but conspicuously pitted ; the pits on the lateral walls forming

a coarse sieve-plate structure often coalescing to form an open scalariform

structure.

Tangential.— Rays very numerous, resinous, medium, chiefly narrow,

I-seriate. Cells (1) somewhat variable, oval or chiefly oblong and narrow,

more or less conspicuously unequal. Cells (2) chiefly uniform, unequal,

often several times higher.

15. S. discolor Muhl.

imiting zone of wood paren-

throughout, radially oval, and

ly at the outer limits of the

rays resinous,

Transverse.— Growth rings broad, the |

chyma chiefly resinous. Vessels predominant

2- to 4-, more rarely 5-compounded especial

growth ring, where they are diminished to } size. Medullary

836 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

prominent and numerous, t cell wide; distant upwards of 6 rows of wood

cells.

Radial.— Rays resinous. Cells a); the upper and lower and termina

walls thick, strongly but finely pitted. Cells (2), the upper and lower and

terminal walls thick, finely but strongly pitted ; marginal and interspersed,

often predominant; the pits on the lateral walls variable and hexagonal, and

forming a coarse sieve-plate structure which often passes through transi-

tional forms into a scalariform structure.

Tangential— Medullary rays resinous, numerous, low to high. Cells (1)

variable, oblong to broadly oval, and conspicuously unequal. Cells (2)

chiefly uniform and narrow, but very unequal and often several times higher

than long, terminal, and pad; often ———À

LITERATURE.

BENTHAM, G., AND Hooker, J. D.

'62-83. Genera Plantarum. London: 3 vols.

BERRY, E. W.

:02a. Notes on the Phylogeny of Liriodendron. Bot. Gaz., vol. 34, pp-

63.

44-

BERRY, E. W.

:02b. Notes on Sassafras.

Bot. Gaz., vol. 34, pp. 426-450, pl. 18.

BERRY, E. W.

:01-:03. Notes on Liriodendron Leaves. Torreya, vol. 1, pp. 105-107 ;

vol. 2, pp. 33-37; vol. 3, pp. 129-132.

BERRY, E. W.

:04a. Additions to the Flora of the Matawan Formation. Bull. Torrey

Bot. Club, vol. 31, pp. 67-82, pls. 1-5.

BERRY, E. W.

:04b. The Cretaceous Exposure near Cliffwood, N. J. Amer. Geol.,

vol. 34, pp. 254-260, pl. 1

DE Bary, A

'84. Comparative Anatomy of the Vegetative Organs of the Phaner-

ogams and Ferns. Oxford: xvi + 659 pp.

Goopwin, W. L.

'88. Ringed Trees. Can. Rec. Sci., vol. 3». Pp. 227-229.

GRAY, A,

'89. Scientific Papers of Asa Gray,

selected by Charles Sprague Sar-

gent. Boston and New York:

2 vols., viii + 397, iv + 503 pp-

No. .467.] STUDY OF THE SALICACEE. 837

Hou, T.

'90. Notes on the Leaves of Liriodendron. Proc. U. S. Nat. Mus., vol.

13, pp. 15-35, pls. 4-9.

Hou, T.

'95. On the Validity of some Fossil Species of Liriodendron. Bof. Gaz.,

vol. 20, pp. 312-316, pl. 23.

KNOWLTON, F. H.

'93. Annotated List of the Fossil Plants of the Bozeman, Montana,

Coal Fields with Table of Distribution and Description of New

Species. Bull. U. S. Geol. Surv., no. 105, pp. 43-64, pls. 5-6.

KNOWLTON, F. H.

'98. A Catalogue of the Cretaceous and Tertiary Plants of North

America. Bull. U. S. Geol. Surv., no. 152, 247 PP-

KNowLTON, F. H.

:00. Flora of the Montana Formation. Bull. U. S. Geol. Surv., no.

163, viii + 118 pp., 19 pls.

LESQUEREUX, L.

'92. The Flora of the Dakota Group. (Edited by F. H. Knowlton.)

Monog. U. S. Geol. Suru., vol. 17, 400 pp» 66 pls.

NEWBERRY, J. S.

'95. The Flora of the Amboy Clays. (Edited by Arthur Hollick.)

Monog. U. S. Geol. Surv., vol. 26, 260 pp., 58 pls.

NEWBERRY, J. S.

The Later Extinct Floras of North America. (Edited by Arthur

Hollick) Monog. U. S. Geol. Surv., vol. 35, xvii + 295 PP» 68

pls.

PEIRCE, G. J.

:04. Notes on the Monterey Pine. Bot. Gaz., vol. 37, pp- 448-445.

PENHALLOw, D. P. : :

:00. Notes on the North American Species of Dadoxylon, with Special

Reference to Type Material in the Collections of the Peter "uh

path Museum, McGill College. Trans. Roy. Soc. Can., ser. 2,

vol. 6, sec. 4, pp- 51-97, 18 figs- a

PENHALLOW, D. P.

:04a. Observations upon some Noteworthy

Bearing upon Palzontological Evidence.

pp. 279-395.

PENHALLOw, D. P.

:04b. Notes on Tertiary Plants. Trans.

sec. 4, pp- 57-79.

PENHALLOw, D. P.

:04c. The Anatomy of the

certain Exotic Species from Japan

vol. 38, pp. 244-273, 331-357» 523-554

Leaf Variations and their

Can. Rec. Sci., vol. 9

Roy. Soc. Can., ser. 2, vol. 10,

North American Coniferales together with

and Australasia. Amer. Nat.,

691-723-

838 THE AMERICAN NATURALIST. | [Vor. XXXIX.

SARGENT, C. S.

'94. The Silva of North America. Vol. 6, Ebenacez.Polygonacez.

Boston: 124 pp., pls. 252-304.

SCHIMPER, A. F. W.

:03. Plant Geography. Oxford: xxx + 839 pp.

SEWARD, A. C.

'92. Fossil Plants as Tests of Climate. London, Eng.

DE Vries, H.

:05. Species and Varieties ; their Origin by Mutation. Chicago: xviii +

847 pp.

WALLACE, A. R.

'80. Island Life. London.

WARD, L. F.

'88. The Paleontologic History of the Genus Platanus. Proc. U. S.

Nat. Mus., vol. 11, pp. 39-42, pls. 17-22.

WARD, L. F.

'96. Some Analogies in the Lower Cretaceous of Europe and America.

tod A Oia. Surv., 16th Ann. Rept., pt. 1, pp. 469-542, pls. 97-107.

WATT, G.

:01. A Plague in the Betel-nut Palms. Agric. Ledg., no. 8, pp. 129

179, pl.

WHITE, D.

:05. Fossil Plants of the Group Cycadofilices. Swithson. Misc. Coll.,

vol. 47, PP. 377-390, pls. 53-55. « :

WIELAND, G. R.

:03. Polar Climate in Time the Major Factor in the Evolution of Plants

and Animals. 4 mer. Jour. Sci., ser. 4, vol. 16, pp. 401-430.

WILLIAMSON, W. C. :

On the Organization of the Fossil Plants of the Coal Measures. I.

Phil. Trans. Roy. Soc. London, vol. 161, PP- 477-509, pls. 23-291

(also later parts).

ERRATA.

Page 515, line 29, for * Proteacez which is preéminently," read Proteacez

which thus appears to be. Line 30, for * 19: 0.00," read 7.0.47.

Page 516, line 9, for “ forty-seven ” read fifty-seven.

Page 516, first line of table, Proteacex, for « 19:0.00” read. 7:0.47; for

Y read 24; for “ 0,00” read zo and insert “the whole” in the

nineteenth line after Araliacez.

MOMENTUM IN VARIATION.

F. B. LOOMIS.

Ever since the theory of evolution was grounded and the fact

that each form and species is the result of accumulated variations

from a less specialized ancestor, was established, this same vari-

ation has been scrutinized to find its causes and laws. Darwin

made it more or less sporadic, and saw in the struggle for exist-

ence the factor which selected the useful variations and eliminated

the less suitable innovations. Later, recognizing many features,

especially ornamental characters, as not useful, he also proposed

sexual selection as a second factor in determining the preserva-

tion of variations. Others, especially paleontologists, have been ,

struck by the fact that variations are in a line, so that useful

features develop rapidly; and second, by the frequency with

which several lines of variation appear in a form practically

simultaneously, all in conformity to the particular habitat and

habit of the possessor. Further, remarkable convergences are

found in animals of different groups when placed in the same

habitat. These facts lead to two lines of thought: first, that

the environment acts on the animal more than merely to select

such variations as chance may offer; and second, that the ani-

mal in its life, by its habits, acquires characters which are handed

to its offspring accentuated, and thus adaptive features are rap-

idly developed. ! ;

. In the above an explanation is found for the development of

useful characters, but there remain still two classes to be

accounted for. First, those which in their early stages are of

no account, but when developed become important (as the cusps

on teeth); and second those which have developed to perform a

useful function but in later forms have reached a degree of spe

cialization which has proved either a hindrance or the destruction

of the possessor. To this class also belong those features devel-

oped to a degree of perfection beyond the requirements of utility

(sponge spicules, Radiolarian shells, some plant blossoms). .

839

840 THE AMERICAN NATURALIST. (Vor. XXXIX.

For instance in the early members of the family of saber-

toothed tigers (Machzerodidz), the upper canine teeth are elon-

gated and flattened, making in such forms as Dinictis and

Hoplophoneus a most efficient weapon. However, the elongat-

ing went on gradually until in a form like Smilodon the great

tushes reach far below the lower jaw, and to open the mouth wide

enough to take in food below the weapons was practically impos-

sible, so that most of the food probably went in between the

a b £

Fic. 1, — Series of saber-toothed tigers’ crania. a, Dinictis ; 4, Hoplophoneus ; ej Smilodon.

canines. At this stage the family, world wide in its distribution,

died out.

Taking this as an illustration of a variation going beyond its

utility, there seems to the writer to be but one adequate expla-

nation, namely, that as a special feature develops it attains à

momentum which tends to carry it beyond the point of greatest

utility. In so doing it may become a hindrance even to the

point of exterminating its possessor, or may merely attain a per-

fection, not detrimental, but without other explanation.

Let this be applied to various groups. In the Radiolarian

shell enough symmetry to maintain the balance of the animal

would be expected, but when a mathematical perfection is shown

in the repetition of every spine and ray in marvelous complexity,

something more than utility has been subserved. The same

may be said of the flesh spicules of sponges. At first being

merely a deposition of something spinous in the flesh, so as to be

disagreeable enough to protect the sponge from being eaten by

small animals, these spicules are later carried to the perfection of

No. 467.] MOMENTUM IN VARIATION. 841

symmetry. These, with the symmetry of sessile crinoids, sea

anemones, and floating jelly-fishes offer illustrations of the carry-

ing of a feature far beyond utility, toward perfect symmetry.

The molluscan Hippurites starts as a form which thickens its

shells, one of them especially; apparently asa protective measure.

But when the shell has reached a thickness of an inch it can

hardly be considered useful to increase it further. However,

these forms go on increasing in thickness to in some cases over

a foot, using up the vitality which would otherwise be available

for reproduction. Momentum seems to be the only reasonable

explanation in such cases, and there are several (Coralliopside,

Gryphea, Caprinidze, etc.).

Among Cephalopoda the complication of the edge of the sep-

tum of various Ammonites offers another case. A sinuous mar-

(a B1

| | ^

s v2 i h Z : d : /

R Pu Pa i ia; Des-

Fic. 2. — Series showing suture lines of Ammonites. @, Goniatites; 4, Medliocottia: c,

moceras.

gin is doubtless a better brace against the pressure of the outside

sea water, and such an irregular line as that of Goniatites or even

Medliocottia (see Fig. 2) would be interpreted as useful. How-

ever, when it is carried to the complication found in Desmoceras

or Pinacoceras, only momentum seems to explain the condition.

Turning to the vertebrates where the balance required for

survival is even more delicate, the tooth of the Labyrinthodonts

842 THE AMERICAN NATURALIST. | [Vor. XXXIX.

is another instance. Here the surface is at first infolded prob-

ably for greater strength, but this is carried to a degree so com-

plex as to be a puzzle to work out. Among the reptiles the

Stegosaurian family adopted a dermal armor which some mem-

bers developed till the double dorsal row of plates set on edge

consisted of pieces some of which are over three feet across and

several inches thick at the base. With such an excessive load

of bony weight entailing a drain on vitality, it is little wonder

that the family was short-ived. Doubtless the elongation of

the snout was useful to the forms ancestral to Teleosaurus, but

carried to the excess found in that genus, it resulted in a weak

grasp, and the form disappeared.

Among the mammals the saber-toothed tigers have been men-

tioned. The mammoth with its extreme development of tusks

may also serve to illustrate the principle. For, while at first the

moderate tusk is an efficient weapon, as soon as it begins to be

recurved as in Elephas primigenius, it loses its defensive value,

and the carrying of the great weight is a drain on the vitality.

A better example is seen in Babirusa where the canine teeth at

first developed to protrude outward and of utility in digging, have

gradually curved up over the snout, and appear more like horns

than teeth. As they are now and were for a considerable por-

tion of their previous development, they must be a serious hin-

drance in feeding. - nm. Lus

The horns of many forms have also developed beyond useful-

ness. Take for instánce those of the elk and moose, where if

useful it is only in conflicts with other "males once a year. But

their great spread is a constant menace, requiring care lest in

running they come to trees not far enough apart to admit of

going between. Then the drain on the animal which sheds

these great bony growths annually and replaces them again,

Is great. It is only as the result of momentum that these cases

seem reasonable.

R en excessively heavy horns, such as those of

p and the big-horn,

weight which lends force in butting c

to offset the disadvantage which they

running. Wherever horns have been d

are developed, the great

an hardly be considered

entail in climbing and

eveloped there seems to

No. 467. MOMENTUM IN VARIATION. 8

be this tendency to carry them to excess, as in Titanotheres,

Tinoceras, Elasmotheres, Irish elk, etc. |

The above are selected examples in which a feature once use-

ful has been developed beyond its maximum utility. Many

others equally striking might be cited, the explanation of all of

which is extremely difficult unless such a factor as momentum is

called in. In the light of this factor, however, a logical and

apparent cause is found. Momentum also explains why a char-

acter that originated in accordance with the environment devel-

ops so rapidly, and why, when an animal had reached adjustment

to its surroundings, it still goes on beyond a perfect adjustment.

It may be laid down as a rule then that a variation started along

any line tends to carry that line of development to its ultimate,

being driven by momentum. If the feature is detrimental the

group dies out ; if, however, it is merely a minor feature it makes

a handicap. A line of development may be stopped and its

momentum overcome but the tendency is to keep right on.

This factor of momentum has not been given the importance

due it, although it is felt in the undercurrent of the thought of

several authors. It is the writer's belief, however, that it should

find an important place in the explanation of animal structures.

AMHERST, Mass.

NOTES AND LITERATURE.

ZOÓLOGY.

A New Comparative Histology.'— The enormous mass of obser-

vations accumulated by histologists during the last decade has been

greatly in need of such a treatment as would reduce its essentials to

a compact and serviceable form. Schneider’s Lehrbuch der vergleich-

enden Histologie, though a most excellent book in many respects, can

scarcely be said to attack the problem from this standpoint, for its

treatment of the subject on the basis of the descriptive histology of

a series of representative animals has given to it so strongly an indi-

vidual bent that it is a voluminous contribution from the author to

comparative histology rather than a résumé of our present knowledge

of that field. The Zraité d’ Histologie by Prenant, Bouin, and Mail-

lard! on the other hand is a most successful attempt at this almost

Herculean task. The work is planned for two volumes, of which the

first, complete in itself, has just been published and the second is

promised before the close of this year.

The first volume, whose subtitle is General and Special Cytology,

is divided into three parts. The first of these includes Book I, deal-

ing with protoplasm and the cell in general; Book II, giving the

general morphology of the cell; Book III, taking up cellular physi-

ology; and Book IV, indicating the lines of cellular differentiation.

The second part, which contains Books V to VIII, has to do with the

various forms of differentiated cells: sensory, muscular, nutritive, and

The third part includes Book IX on cell multiplication,

and XI on cellular degeneration and

has received an exhaustive and

sustentative.

X on individual reproduction,

death. Each of these subjects

thorough treatment and not only are the facts concerning a given

form of tissue well recorded but the present stand of the appropriate

theoretic questions is unusually well stated. From the standpoint of

a comparative histology which seeks to give the reader the main facts

of the science and to orient him so far as the chief theoretic questions

are concerned, the volume is without an equal and should prove a

great boon to all histologists.

1Prenant, A., Bouin, P., et Maillard, L. Traité d Histologie. Tome 1, Cyto-

logie générale et spéciale. Paris, C. Reinwald, 1904. xxxii + 799 pP- 791 figs.

845

846 THE AMERICAN NATURALIST. | [Vor. XXXIX.

In one respect the volume falls short of what it might have been.

Little or no attention is given to the phylogeny of tissues and while

this aspect of the subject is necessarily chiefly theoretic, a broadly

grounded treatment cannot afford to omit it. Aside from this the

volume is most acceptable. The presswork is excellent and the

numerous figures, many of which are in color, afford a most ample

body of illustrations for the text. There is a very full table of con-

tents and an excellent index.

CH- P

Studies in Heterogenesis.!— One hundred years ago, Oken be-

lieved he had evidence that animal and vegetable tissues disintegrate

after death to give rise by rearrangement of their elementary parts

to minute living things which combine in larger and larger aggregates

to form the myriads of infusion-dwelling microscopical organisms.

Such an hypothesis is excusable with Oken in 1805, but in 1905,

after more than sixty years of cell study, — after complete establish-

ment of the dictum omnis cellula e cellula, the limit of toleration is

overreached and we read with ever growing impatience the mass of

so called evidence that dead protoplasmic substance is directly meta-

morphosed into living organisms of diverse species, genera, and even

kingdoms.

This “evidence” is beautifully presented in 350 pages of letter

press, with an appendix of 35 pages, and with 815 illustrations from

microphotographs, by which, as the author tells us, the careful student

can “help to break down the barrier of incredulity which at present

excludes any general acceptance of the truth and universality of those

processes of heterogenesis by means of which, as I believe, the lower

forms of life, both animal and vegetal, are ever springing up anew in

countless myriads from matrices wholly unlike themselves” (page 3).

The photographs are fairly well taken and illustrate many common

forms In stagnant waters but to present them as proof of heterogene-

sis recalls the natveré of the small boy offering his pole and line as

evidence of the ten-pound bass that escaped his hook.

Without going too much into details here, we may sum up the

author's pomt of view by the following results which he believes are

proved by his “evidence ” : —

; wo Aggregates of bacteria in the zoóglcea stage may be transformed

nto i ;

; ungus germs, or into Amaebze, Mastigophora, or even into ciliated

nfusoria (pp. 65-108),

' Bastian, H. C. Studies in Heterogenesis.

; London, Williams and Norgate

1903. Svo, ix + 354 + xxxvii pp., 19 pls. /6. en

No. 467.] NOTES AND LITERATURE. 847

2. Ciliated Protozoa may be formed indifferently from such zoó-

gloea masses, or from the substance of Amcebe (pp. 113-118), or

from encysted Euglena (pp. 110-113), or from the eggs of Macrobi-

otus (pp. 138-144) and rotifers (pp. 44-45).

3. Diatoms, even, may arise de novo from the cells of a parasitic

alga (pp. 158-168); or Actinophrys from the substance of Nitella

cells, or from Euglena (p. 224). The latter, indeed, seems to be

something of a protoplasmic Pandora's box from which emerge Pera-

nema (p. 13), Polyphagus (p. 224), Olpidium (p. 226), Chytridium

(p. 232), Chlamydomonas (p. 234), Amoeba (p. 235), or higher alga

like Vaucheria (p. 188) and Conferva (p. 191), while its own proto-

plasm may be only the metamorphosed substance of an algal cell

(CEdogonium).

As to the method employed in obtaining these remarkable find-

ings there is little said; isolation and continuous observation were

deemed unnecessary and fruitless. Tap water with hay for example,

was heated to not more than 125? F. and left to stand. A scum de-

veloped after a few days, in which, from day to day, various types of

organisms, including monads, fungus germs, Actinophrys, and even

ciliates were observed, all having developed, he concluded, from

*embryonal areas" of the scum. These observations are seriously

presented as proving the heterogenetic origin of the different forms.

Answering a criticism from certain “learned societies" that had

refused to accept his conclusions based upon this method of observa-

tion, Bastian states: “I submit that such evidence as has been

brought forward in this volume is the only kind of evidence that can

be adduced in proof of heterogenesis" (p. 344). and this statement,

if limited to his use of the term heterogenesis, is one and the only

one in which we heartily and unqualifiedly agree with the De

Herrick's Home Life of Wild Birds.!— In the four years since

the appearance of Professor Herrick's earlier work under this title,

he has been able to extend his studies of nesting habits to a larger

number of species and individuals, and in the present revised edition

of his book “much has been re-written, and forty-eight new illustra-

tions have been added to the text in place of a smaller number

omitted. The first three chapters have been materially changed;

!Herrick, Francis H. The Home Life of Wild Birds. A a er y x

Study and Photography of Birds. New York and London, G. P. Putnam :

1905. Svo, xxv + 225 pp», illus. $2.00. ;

845 THE AMERICAN NATURALIST. | [Vor. XXXIX.

Chapter XI. on Nest-Building is entirely new, as are also in large

measure those which follow on The Development and Care of the

Young and on Life and Instinct." The size of the volume has been

reduced so as to make it serviceable for field use.

For the serious and minute study of the life of birds at their nests,

the author's * method" has its great advantages as well as its limita-

tions. A small tent, described fully in Chapter III, * Tent and Cam-

era," is erected within arm's length of the nest to be studied and the

observer is enabled to watch the activities of the birds through a

small window cut at the proper height in the tent-wall. The camera

is also used from the shelter of the tent. In cases where the nest

cannot be conveniently reached from the ground it is removed

together with the nesting-limb and set up in a favorable spot, where

it may be readily observed from the tent. The instinct of the parent

birds to care for their young is so strong that they soon return to

their charges and, finding that no harm comes from the tent, they

quickly learn to disregard it entirely. It is important to note, how-

ever, that such liberties may not be taken with a nest until the young

are hatched and are a few days old, for if disturbed earlier than this

the old birds will desert. For this reason the very early life of the

nestling cannot be so well studied by this method. Professor Herrick

has used his “method,” with good judgment and in but “four or

five cases when the nest with its supports has been displaced . . . . have

the young come to grief, in the course of five vears’ work.”

The first three chapters of the volume are given to an exposition

of the “method,” then follow chapters on the nesting habits of the

robin, the cedar-bird, the red-eyed vireo, the bluebird, the catbird,

the nighthawk, and the belted kingfisher, with photographic repro-

ductions of the various activities that take place at the nest. The

remaining chapters are of a more general nature and treat briefly of

nest-building, the development and care of the young, life and instinct,

and the instinct of fear in young birds. From his studies of a num-

ber of species, the author has come to regard a large part of the activ-

ities of nesting as instinctive. “Birds seem to follow one line of

conduct, whether it be building nests, sitting over eggs, or brooding

and tending the young. until their instinct in any given direction has

been satisfied, thus normally completing one term of the series before

passing to the next in sequence .... Each term of the cycle is cap-

able of analysis into many minor components, differing not only in

the sexes, but in different species, and subject to change in different

individuals . ... One instinct may be overdone, as when a bird like

No. 467.) NOTES AND LITERATURE. 849

the phoebe builds more than one nest, in which case her building

instinct is apparently not satisfied by the usual exercise, or another

may be scamped, as when swallows, house martins, or swifts desert

their young in order to start on their migrations. When one instinct

has been satisfied, wild birds must obey the next in sequence, which

seems to possess them with the force of a resistless passion."

Apart from its interest as literature, the book from a purely scien-

tific point of view, contains much of value with regard to the habits

of certain of the species treated. Thus the nighthawk is found to

feed its young, in one case at least, upon fireflies; the cleaning of

the nest and removal of excreta is a duty regularly performed by the

small birds studied; the parents do not attempt to feed each young

bird in turn impartially, but often thrust food into a nestling's throat

and withdraw it to try a second or a third young one until a bird

with the “proper reaction time," z. e, whose swallowing reflex is .

stimulated, is found. Brooding, or shielding the young from the heat,

is part of the parents' duty on hot days, and it would be of interest

to determine if this act is confined to birds that build open nests.

Domed nests might be expected to dispense with the necessity for

shielding the young from the sun's heat and possibly this may ex-

plain their origin.

The book itself is well printed and profusely illustrated. The

style is popular but the author has used much judgment in his treat-

ment of a field which * in the direction of both observation and experi-

ment is of boundless extent, while on the side of inference it is full

of pitfalls." The remarkable photographs by which the book is

illustrated, add largely to its interest and value. E

Trouessart's Catalogus Mammalium, Supplement, Fasc. p

The concluding part of this work, the first three fascicles of which

have already been noticed in these columns (Amer. Nat., vol. 39, pp-

603-605), lists the known living and fossil Cetacea, Edentata, Marsu-

pialia, Allotheria, and Monotremata, and brings the total of known

mammalian species up to 9381, an increase of 2157 over the b sri

listed in the Catalogus of 1897-99. Among the Cetacea the iem

need for revisionary work is apparent and many of the species e

doubtless be found to be merely nominal when more material can

lTrouessart, E. L. Catalogus Mammalium tam Viventium n mn

Quinquennale Supplementum (1899—1904). Fasc. 4. Berlin, R. Frie

Sohn, 1905. 8vo, pp. i-vii, 753-929. 8 Marks.

850 THE AMERICAN NATURALIST. [Vor. XXXIX.

gathered and studied. Forster's name, ampullatus, revived by Rhoads

(Science, N. S., vol. 15, p. 756, 1902) appears to have escaped the

compiler, and seems applicable in place of rostratus for Hyperoödon.

Four new generic names are proposed, to take the place of others

that are preoccupied. Sphenodontherium for Sphenodon, Heterodon-

therium for Heterodon, and Propareutatus for Pareutatus among the

Edentata, and Odontocyrtus for Kurtodon among the Marsupialia.

The compiler also deems it necessary to amend the name Tatu to

Tatus. The index includes those specific names only that have

figured in works published since the previous catalogue.

G. M. A.

BOTANY.

Britton's Manual. — In form, the recently issued second edition

of this now well known work conforms closely to the first edition pub-

lished in 1901. Analytical keys to the families, prepared by Wiegand,

have been added to the prefatory matter, and a key to the genera of

Compositz, also prepared by him, has been placed at the end of the

treatment of that family. The lamentable absence of necessary syn-

onymy from the first edition has been rectified to a considerable extent ;

and in addition to such corrections as were possible in the original

text, the appendix has been amplified by the incorporation of descrip-

tions of over 100 species not recognized in the earlier edition, while,

e. g., under Cratzgus, the fact that still others have been published

is indicated.

W. I.

A New North American Flora 2 Since the appearance some years

ago of the latest fascicle of the Synoptical Flora begun by Asa Gray,

there has been no evident effort to provide a collective systematic

treatment of the plants of the entire United States, though several

handbooks covering a part of the country have appeared.

The fascicle now under review, though pertaining to a volume far

M d

"A nd N.L. Manual of the Flora of the Northern States and Canada. New

e : : enry Holt and Co, 1905. 8vo, 2 ed., revised and enlarged, xxiv +

RRE N

* North America Flora, vol. 22, part 1.— Published by the New York Botanical

arden, May 22, 1905. Large 8vo, 80 pp. $ı.;o,

No. 467.] NOTES AND LITERATURE.. 851

advanced in the series is in reality the initial number of a new work

which is intended to describe the wild plants of all groups not only

of the United States but of the remainder of North America, includ-

ing the West Indies. The editorial management has been under-

taken by Doctors Britton and Underwood, who have associated with

themselves an advisory committee of representative American botan-

ists, and who depend upon the collaboration of a large number of

specialists. Thirty volumes of four or five fascicles each are in con-

templation, and a special fund set aside for this purpose by the New

York Botanical Garden provides for the publication of the several

parts as they are prepared.

The present fascicle, which is attractively printed and provided

with analytical keys for all of the groups treated, is devoted to the

first four (Podostemonacez, Crassulacez, Penthoracez, and Parnas-

siaceze) of the twenty-four families recognized as representing the

order Rosales; the first being handled by Nash, the second by Brit-

ton and Rose, and the third and fourth by Rydberg, the ordinal key

and description being by Small.

So large an undertaking is subject to many dangers and is certain

to suffer many mishaps; and, considering the imperfect herbarium

data and the impossibility of extensive field research if the work is

to be pushed forward with any speed, it may be said that each fasci-

cle is likely to become antiquated in a very short time after its pub-

lication, so far, at least, as the tropical regions are concerned, — the

more rapidly, indeed, in proportion to its own critical excellence.

There appears to be no other way, however, of making possible the

ultimately complete flora of this enormous and botanically rich terri-

tory that every botanist feels the need of, and the editors should

count on the active support of all who can help them forward with

their plans. Ww. T

Ames's Studies in the Family Orchidacez.!— A new irregular-

interval publication, somewhat comparable with Hooker's Jcones

Plantarum, the Jcones Selecte Horti Thenensis, etc., has been

launched under the auspices of a publisher's house which does vd

good and attractive work. Its purpose is to present the results z

investigation on one of the largest and best known collections o

ations and Studies of the Family Orchida-

Ausetts

1 3 Aidacee. Jllustr:

Ames, Oakes. Orchidace otanical Laboratory, North Easton, Massachusetts.

8vo, fasc. 1, vi 4-156

cee, issuing from the Ames B ds:

Boston and New York, Houghton, Mifflin and Co., 1905.

pp., 16 pls.

852 THE AMERICAN NATURALIST. | [Vor. XXXIX.

orchids cultivated in the United States, its scope being limited to

this family of plants. The first fascicle, issued on April 8, con-

tains illustrations, critical notes, and technical descriptions covering

a wide range of genera in the family and a number of countries.

The most interesting feature for American botanists is a critical

paper called * Contributions toward a Monograph of the American

Species of Spiranthes," to which 33 pages are devoted.

W. T.

Notes.— The fourth of Rose's * Studies of Mexican and Central

American Plants " (Contributions from the U. S. National Herbarium,

vol. 8, part 4), like its predecessors is an important addition to the

published information about the plants of the high tableland. The

author states that none of the many new species it contains have

been described until all their known Mexican relatives had been

studied, and in most cases a synopsis of the genus prepared,— a

procedure that speaks well for the conclusions reached.

A paper on plants eaten by the ancient Mexicans, by Urbina, has

been published from the Museo Nacional of Mexico.

Nuttall's Journal of Travels into the Arkansas Territory during the

Year 1819, with Occasional Observations on the Manners of the Aborig-

ines, published at Philadelphia in 1821, is reprinted as vol. 13 of the

Early Western Travels being edited by Dr. Thwaites of the Wiscon-

sin Historical Society.

Under the title * Plant Migration Studies," Professor Bessey has

distributed from University Studies, vol. 5, no. 1 (University of Ne-

braska) separates of an analysis of the distribution of Nebraska trees

and the factors which have influenced it,— with 67 thumb-nail maps

of the State, referring to as many trees.

The forest conditions of northern New Hampshire are considered

by Chittenden in Bulletin no. 55 of the Bureau of Forestry, U. S.

Department of Agriculture. |

A paper entitled * Additions to the Flora of Subtropical Florida," by

Small, has recently been issued in the Buletin of the New York

Botanical Garden.

A contribution to the flora of the Bahama Islands, by Britton, is

separately printed from vol. 3, no. 11,0f the Bulletin of the New York

Botanical Garden.

No. 467.] NOTES AND LITERATURE. 853

A monograph of Portuguese Orobanchacez, by Guimaraes, is pub-

lished in Broteria for 1904.

Among other forest views, the Report of the Forestry Bureau of

the Philippine Islands for the year ending September 1, 1903, recently

issued, contains a good photogram showing the aérating roots of

Bruguiera caryophyllaoides.

Mutation is discussed from various points of view in a series of

papers printed in Science of April 7.

The megaspore membrane of Gymnosperms forms the subject of

a paper by Thomson, published as no. 4 of the biological series of

University of Toronto Studies.

Haywood publishes a paper on the injury to vegetation by smelter

fumes, as Bulletin no. 89 of the Bureau of Chemistry, U. S. Depart-

ment of Agriculture.

The great scope of economic botanical study by the Government

Bureau of Plant Industry, which spends annually nearly a million

dollars, is well shown by the recently issued Report of the Secretary of

Agriculture for the Year ending June 30, 1904.

The prickly pear and other cacti as food for stock are discussed

by Griffiths in Bulletin no. 74 of the Bureau of Plant Industry, U. S.

Department of Agriculture.

A paper by Mann and Hunter on sisal-hemp culture in the Indian

tea districts has been published recently by the Indian Tea Associa-

tion of Calcutta.

An illustrated article on commercial Catalpa growing, by Gleason,

is contained in Country Life in America for May.

Vol. 9 of the Contributions from the U. S. National Herbarium con-

sists of an account of the useful plants of the island of Guam, by

Safford.

Some large trees are noted and figured by Tavares in vol. 3 of

Broteria. :

The remarks of a number of biologists, chemists, and spes

on the use of copper sulphate for the purification of water supplie

are published in ‚Science of April 21.

The decays of timber due to higher fungi are :

6 of Lafar's Handbuch der Technischen Mykologte,

ume 3.

reached in Lieferung

pertaining to vol-

854 THE AMERICAN NATURALIST. [Vor. XXXIX.

The fungous diseases of orchard trees are considered by Wilcox in

Bulletin no. 132 of the Alabama Agricultural Experiment Station.

Three (edible) species of Coprinus are figured by Arthur in Bul-

letin no. 98 of the Purdue University Experiment Station.

Sclerotinia padi and the diseases it causes are described by Lam-

bert in an illustrated article in Gartenflora of April ı.

Nomenclatorial type specimens of plant species are discussed by

Hitchcock in Science of May 26. In connection with some of the

suggestions of this article should be read another, on general

grounds, by Schuchert, in the same journal of June.

A noteworthy monograph of the genus Nymphza, in quarto (xiii +

279 pp. 30 pls.), by Conard, has recently appeared as Publication

no. 4 of the Carnegie Institution of Washington.

The development of Sarracenia purpurea is discussed by Shreve

in The Johns Hopkins University Circular, no. 178.

Maiden's revision of the genus Eucalyptus has reached the 6th

part, ending with p. 180 and pl. 32.

An anatomical study of Croomia paucifolia is published by Holm

in Zhe American Journal of Science for July.

A revision of the genus Zexmenia, by Jones, forms n. s., no. 30, of

the " Contributions from the Gray Herbarium of Harvard University,"

published as vol..41, no. 7, of the Proceedings of the American Academy

of Arts and Sciences, issued June 23.

Stages in the development of Sium cicutefolium are described by

Shull in Publication no. 30 of the Carnegie Institution of Washington.

: api publications on South American cacti are: Arechavaleta,

ora Uruguaya,” 2 entrega, forming part of the Anales del Museo

Nacional de Montevideo; and Spegazzini, * Cactacearum Platensium

Tentamen,” in ser. 3, vol. 4, of the Anales del Museo Nacional de

Buenos Aires, which Mr. Berger is summarizing in recent issues of

the Monatsschrift für Kakteenkunde.

A paper on the haustoria of Santalum, by Barber, is published in

The Indian Forester for April.

per on the development of Phytolacca decandra, by Lewis, is

brace in The Johns Hopkins University Circular, no. 178.

No. 467.] NOTES AND LITERATURE. 855

A preliminary paper by Johnson, on seed development in the

Piperales and its bearing on the relationship of the order is pub-

lished in no. 178 of Zhe Johns Hopkins University Circular.

An account of the Jamaican species of Lepanthes, by Fawcett and

Rendle, forms vol. 7, part 1, of the current botanical series of Zrans-

actions of the Linnean Society of London.

Teratological flowers of Agave are described by Maige in the Revue

Generale de Botanique of April 15.

The North American species of Agrostis are revised by Hitchcock

in Bulletin no. 68 of the Bureau of Plant Industry, U. S. Department

of Agriculture, under date of April 29.

A facsimile reprint of Cutler's “An Account of some of the Vege-

table Productions naturally growing in this Part of America," from

the first volume of Memoirs of the American Academy of Arts and

Sciences, forms no. 7 (reproduction series no. 4) of the Bulletin of the

Lloyd Library, issued in 1903.

An account of the vegetation of the “Sotol Country” in Texas, by

Bray, forms Bulletin no. 60 (scientific series no. 6) of the University

of Texas.

An illustrated popular account of desert vegetation is given by

Sharlot M. Hall in Out West for June.

Volume g of the * Flore de France” of Rouy, Foucaud, and Camus,

published as the Annales de 1904 of the Académie de la Rochelle,

deals with Composite.

An account of new plants from the islands of Margarita and Coche,

Venezuela, by Johnston, forming no. 29 of the new series of “ Con-

tributions from the Gray Herbarium of Harvard University," has

recently been published as no. 21 of the current volume of Proceed-

ings of the American Academy of Arts and Sciences.

A paper on the vegetation of Madeira, by Vahl, is contained in

vol. 36, part 2, of Engler’s Botanische Jahrbücher.

Vacciniacez and Ericacez (in part) are treated in the recently

issued vol. 4, sect. 1, parts ı and 2, of the “ Flora Capensis ” edited

by Sir W. T. Thiselton-Dyer.

Papers on Indigofera (by Baker) and Aloé (by Schónland) are

contained in vol. 1, part 4, of the Records of the Albany Museum, of

Grahamstown.

856 THE AMERICAN NATURALIST. | [Vor. XXXIX.

The biological significance of leaf-fall is discussed by Wiesner in

the Berichte der deutschen botanischen Gesellschaft of May 25.

A review of the identifications of the species described in Blanco's

Flora de Filipinas, by Merrill, constitutes no. 27 of the publications

of the Bureau of Government Laboratories, Manila, bearing date of

April, 1905.

A paper by Pond on the biological relation of re plants to

the substratum has been separately issued, recently, from the U. S.

Fish Commission Report for 1903.

Duggar's St. Louis address on present problems in plant physiol-

ogy is printed in Science of June 23.

A translation, by Lloyd, of Goebel’s St. Louis address on the fun-

damental problems of present-day plant morphology is published in

Science of July 14.

The mutations of Lycopersicum are discussed by White in Zhe

Popular Science Monthly for July.

A thesis on fruit and vegetable colors, by LaWall, is published in

The American Journal of Pharmacy for July.

An important paper on the fly-galls of Juniperus is published by

Howard in vol. 1, no. 2, of the ninth series of Annales des Sciences

Naturelles — Botanique.

A paper on the morphology and anatomy of the stem of Lycopo-

dium, by Jones, forms vol. 7, part 2, of the current botanical series

of Transactions of the Linnean Society of London.

An extensive paper on the development of the ascus and spore

formation in Ascomycetes (Contribution no. 61 from the Crypto-

gamic Laboratory of Harvard University) is published as vol. 32;

no. 4, of the Proceedings of the Boston Society of Natural History.

The recently issued 17th volume of Saccardo's Sylloge Fungorum

forms part 6 of the Supplementum Universale to the original work.

Postembryonal stages of the Laminariacex are described by

Setchell in vol. 2, no. 4, of the University of California Publications

— Botany.

A short Paper on some Yellowstone diatoms is published by

Edwards in Nuova Notarisia for July.

The cell structure of Cyanophycez forms the subject of a paper

No. 467.] NOTES AND LITERATURE. 857

by Fischer, published as no. 4-6 of the 63d volume of the Botanische

Zeitung, I Abtheilung.

No. 8 (Mycological series no. 3) of the Bulletin of the Lloyd

Library, dated April, 1905, contains an account by C. G. Lloyd of

the Lycoperdacez of Australia, New Zealand, and neighboring islands.

An important paper connecting many Fungi Imperfecti with

Ascomycetous forms has been published by Klebahn in vol. 41, heft

4, of the Jahrbücher für wissenschaftliche Botanik.

“Asparagus and Asparagus Rust in California" is the title of a

well illustrated paper by Smith, published as Buletin no. 165 of the

Agricultural Experiment Station of that State.

A paper on the grain-rust epidemic of 1904, by Carleton, forms

farmers’ Bulletin no. 219 of the U. S. Department of Agriculture.

Atkinson and Shore have published an illustrated paper on mush-

room growing for amateurs as Bulletin no. 227 of the Cornell Uni-

versity Agricultural Experiment Station.

A paper on apple scab and cedar rust, by Emerson, forms Bulletin

no. 88 of the Agricultural Experiment Station of Nebraska.

Orchard diseases are discussed by Wilcox in Bulletin no. 132 of

the Alabama Agricultural Experiment Station.

. A popular summer key to our trees, by Julia Ellen Rogers, is pub-

lished in Country Life in America for July.

Volume 3 of Marshall Ward's 7»ees deals with flowers and inflor-

escences, descriptively treated with reference to British forms.

Alwood, Davidson, and Moncure describe the composition of cider

as determined by dominant fermentation with pure yeasts, in Bule-

tin no. 150 of the Virginia Agricultural Experiment Station.

An agricultural-geographical study of rubber plants, with map,

by Reintgen, forms no. 2-3 of the current volume of Beihefte sum

7; OIRNE

An account of native and introduced saltbushes, by Elias Nelson,

forms Bulletin no. 63 of the Wyoming Experiment Station.

The Mexican “ guayule ” (Parthenium argentatum) used as a source

of caoutchouc, is the subject of an article by Endlich in Der Tropen-

Pflanzer for May.

A well illustrated article by Fullerton, on “ Roots We a is con-

tained in Country Life in America for July.

858 THE AMERICAN NATURALIST. (Vor. XXXIX.

The wild legumes of Maryland are considered by Norton and

Walls in Bulletin No. roo of the Maryland Agricultural Experiment

Station.

A first paper on Wyoming forage plants and their chemical com-

position, by Knight, Hepner, and Nelson, forms Bulletin no. 65 of

the Wyoming Experiment Station.

A paper by Laurent on the “Flore pliocéne des Cinérites du

Pas-de-la-Mongudo et de Saint-Vincent-la-Sabie (Cantal)" forms vol.

9, part 1, of the Annales du Musée d’ Histoire Naturelle de Marseille.

The Journals. — Botanical Gazette, April:— Thaxter, “A New

American Species of Wynnea”; Shoemaker, “On the Development

of Hamamelis virginiana” ; Christman, * Sexual Reproduction in the

Rusts ” ; Whitford, ** The Forests of the Flathead Valley, Montana”;

Livingston, * Note on the Physiology of Stigeoclonium ” ; Trow, “ Fer-

tilization in the Saprolegniales.”

Botanical Gazette, May :— Dean, “On Proteolytic Enzymes —1”;

Cardiff, “ Development of Sporangium in Botrychium ” ; Livingston,

^ Physiological Properties of Bog Water”; Darbishire, “ An Appara-

tus for observing the Transpiration Stream ” ; Lyon, “ Polyembryony

in Sphagnum”; Maxon, “ Adenoderris, a Valid Genus of Ferns."

Botanical Gazette, June :— Arthur, * Leguminous Rusts from

Mexico"; Cannon, *On the Water-conducting Systems of some

Desert Plants” ; Caldwell, * The Effects of Toxic Agents upon the

Action of Bromelin ” ; Sargant, “ The Early History of Angiosperms.”

The Bryologist, May :— Fink, * Further Notes on Cladonias—V”;

Arnell, * Phzenological Observations on Mosses” ; Towle, “Notes on

the Fruiting Season of Catharinea ”; Sargent, * Lichenology for

Beginners ”; Britton, * Notes on Nomenclature —V ” ; Cardot, “Notes

on some North American Mosses — II” ; Wood, “ Additions to the

Lichen Flora of Long Island ”; Grout, “Notes on Vermont Bryo-

phytes " ; Holzinger, “ Two Changes of Name."

The Bryologist, July : — Evans, “ Diagnostic Characters ‚in the

Jungermanniacex ”; Andrews, “ Additions to the Bryophytic Flora

of West Virginia”; Sargent, « Lichenology for Beginners — II”;

Nicholson, “ Tortula pagorum" ; Britton, * A Long Lost Genus to the

United States — Erpodium ” ; Fink, *What to note in the Macro-

scopic Study of Lichens."

(No. 466 was issued Oct. 16, 1905.)

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THE

AMERICAN NATURALIST.

Vor. XXXIX. December, 1905. No. 468.

ECOLOGY OF THE WILLOW CONE GALL.

ROY L. HEINDEL.

AMONG the numerous galls to be found everywhere, the cone

galls of the willows are very common forms. A little has been

done toward their knowledge by Walsh, who has dealt more par-

ticularly with descriptions of the galls and their makers and has

done little more than make casual mention of ecological rela-

tions. An examination of the galls in fall or winter shows them

to be the abiding place of the larvae of a goodly number of

insects. Walsh says: “Nothing gives us a better idea of the

prodigious exuberance of insect life, and of the manner in which

one insect is often dependent upon another for its very exist-

ence, than to count up the species which haunt, either habitually

or occasionally, one of these willow-galls, and live either upon

the substance of the gall itself or upon the bodies of other

insects that live upon the substance of the gall."

In the following pages will be discussed, first, the galls them-

selves, second, the gall makers, and third, the guests and para-

sites that inhabit the galls.

859

860 THE AMERICAN NATURALIST. [Vor. XXXIX.

THE CONE GALLS. -

As is well known, a gall is some abnormal growth of a plant

tissue resulting from an external stimulus. In the case of the

cone galls and of the other bud galls of the willow the stimulus

is furnished by the gall gnat. Whether it is given by the inser-

| tion of the ovipositor into the bud, by the presence of the egg,

or by the larvae, I cannot say. The gall attains its full growth

by midsummer thus giving evidence of considerable stimulation.

Regularity and symmetry in the shape of the gall can be

accounted for by the stimulus, whatever it may be, acting

equally in every direction.

As a result of this stimulus, the bud takes on a remarkable

C p C wW * r

Fic. 1.— Cone gall of Salix. a,5, c, Salicis g phaloides (st

d, Salieis strobiliscus ; e, f, Salicis strobiloides.

k of stem):

activity in growth, and develops a large number (60-75) of

scales. These scales are placed in regular order, with their

edges overlapping, and form in the center an elongate cell.

This cell, protected by the numerous layers of scales, is the

abiding place of the gall maker during its larval and pupal

stages.

No. 468.] THE WILLOW CONE GALL. 861

_ The three cone galls on which I have based most of my study

are all found in the vicinity of Lake Forest, Illinois. I also

gathered some material in southwestern Wisconsin. They are

formed from apical buds. In structure and appearance they are

much alike but they have some characteristic differences. The

three are; —

I. A pubescent gall found growing on Salix cordata Muhl.,

which corresponds in every particular to the gall found by Walsh

on the same willow. This is the gall .SaZrezs strobiloides O. S.

(Fig. 1, e and f). It is usually somewhat spherical but occa-

sional galls have the central scales prolonged into a loose tip.

It is the dense silvery pubescence which distinguishes this gall

most clearly from the others.

2. A cone gall usually more tapering than the above and

lacking the dense pubescence. Its marked characteristic is a

decided curve or bend in the twig just beneath the gall (Fig. r,

a, b,c). In every respect the gall corresponds to .SaZzzs gna-

phaloides Walsh, but in no case have I found it on Salix humilis,

the willow to which Walsh accredits it. Instead, I have found

it in great abundance on Salir bebbiana.

3. A gall corresponding exactly to .SaZezs gnaphaloides,

except that the twig is straight (Fig. 1, 7), was also found on

Salix bebbiana, the Salix rostrata of Walsh’s paper. These

galls were not in such great abundance and were usually to be

found on the same plant with the gall S. gunaphaloides. In some

two or three cases small shrubs bearing only a few galls had all

straight-stemmed ones. On one shrub with 37 galls, 9 were

straight and 28 were crooked. From another clump of willows

(S. bebbiana) I gathered 65 galls, of which 57 were crooked and

only 8 straight. In both cases there was a gradation in the

matter of the crook.

Since I shall show a little farther on that these three galls

have the same maker, it is evident that the distinction between

the first and the others may be due to the peculiar reactions of

the different willows to the stimulus which causes the growth

But in the case of the two galls on S. bedbiana the

of the gall.

It will be neces-

cause of the difference does not seem so clear.

sary to observe the beginning of the gall to see if this can be

determined.

862 THE AMERICAN NATURALIST. [Vor. XXXIX.

In his Origen of Floral Structures, Henslow has drawn an

analogy between the gall and the flower. He intimates that

the gall is the result of the shortening of the axis due to punc-

turing in the depositing of eggs by insects, and thus represents

a lessened growth of twig. I believe that the gall does not

represent a shortening of the axis, but, on the other hand, rep-

resents a special growth of scales in addition to the normal

growth of twig. I base my belief on the following observa-

tions : —

1. The scales of the gall have not the normal leaf arrange-

ment or venation. From a single clump of willows (S. bebbiana)

I gathered a number of twigs and galls. The lateral buds of

this willow have the two fifths arrangement. If the gall repre-

sents a shortening of the axis the scales ought to show some

such arrangement, allowing for a reasonable amount of displace-

ment owing to crowding. While the general arrangement of the

scales was in whorls, some showed a spiral arrangement but

never thetwo fifths. I examined in detail about a dozen galls to

determine this. Moreover the scales do not very much resemble

the leaves of the willows. They differ in shape and margin and

show little or no venation and never the venation of the leaf.

2. The gall-bearing shoot is oftenest longer than the non-

gall-bearing and develops more lateral buds. From this same

bunch of twigs I took 28 bearing the crooked galls and the

same number of non-gall-bearing twigs. The average number

of lateral buds to the gall-bearing twigs was 20, while the aver-

age to the non-gall-bearing twigs was only 161. Eleven gall-

bearing and ten non-gall-bearing twigs were taken from the

same part of the plant, having had, as nearly as could be deter-

mined, the same conditions of growth. The former had an

average of 174* lateral buds and an average length, from origin

of the twig to the base of the gall, of 6.84 inches, and the latter

had an average of 17 lateral buds and an average length to base

of terminal bud of 6.825 inches. In every case the twigs were

of 1904 growth. General observations of various clumps of wil-

lows confirmed the foregoing results. However, in one case the

average length of five pubescent gall twigs (Salix cordata) was

1.13 inches less than the average length of seven non-gall-bear-

No. 468.] THE WILLOW CONE GALL. 863

ing twigs growing under similar conditions. The former aver-

aged three more lateral buds to a twig than the latter. From

another clump of willows 14 twigs bearing pubescent galls had

an average of three buds fewer than 14 non-gall-bearing twigs

(15 and 18) but the average length was equal.

I conclude. that the gall does not represent a shortening of

the axis and that the gall-bearing twig does not represent a

lessened growth, but that, on the other hand, the gall-bearing

The larger shows protruding pupal skins

Fic. 2.— Two cone galls showing extremes in size. ' !

i d stem of the smaller is a bud favorably

of the moth Acleris. At the base of the crooke

placed for continuing growth in a direct line.

twig holds its own with the non-gall-bearing and has in addition

the abnormal growth of the gall.

The very abnormal shape of the stem of the crooked gall sug-

gests a question as to its purpose. Since the gall terminates

the twig and prevents further apical growth, future growth must

864 THE AMERICAN NATURALIST. [Vor. XXXIX.

be by means of a branch originating on the twig below the

gall. At first it appears as if the crook in the stem (see Fig. 2)

might provide for a direct growth by means of a branch from

the convex side of the stem. Dr. P. Speiser claims that a bend

in the stem is of advantage in this way in the gall Dichelomyia

rosaria H. Lw., since the gall is turned aside, and thus permits

a more or less direct growth from a bud below it. An examina-

tion of any willow bearing these crooked galls (S. graphaloides)

shows very plainly that the benefit for continued growth is acci-

dental rather than habitual. To be of service it would be nec-

essary that a bud be located just at the beginning of the crook

in the stem. In one lot of 57 galls, 32 had buds so located and

25 were without bud in a favorable position. By watching the

willows for further information, I found that very frequently the

favorably placed bud either does not develop or sends off a

branch at an angle from the parent twig. And just as fre-

quently, when there is no bud so favorably located, a bud far-

ther down, or one immediately beneath the gall, is the one which

sends out the most vigorous branch, whose direction is deter-

mined by its surroundings.

THE GALL MAKERS.

The life history of the gall gnat is very simple. In the spring

the larva which has spent the winter in its cell in the gall trans-

forms into the pupa and that, a little later, into the gall gnat

itself. The gnats soon deposit their eggs in apical buds of wil-

lows. From the eggs larve are hatched and the cycle begins

again. Walsh speaks of observing larv as late as April 23, and

pupæ from early in April until late in May. From galls gathered

and examined on the following dates I found larvze

gnats: October, November 12,

ruary, about March 20, and the

of the gall

December 26, January 17, Feb-

! i first and second weeks of April.

In March and April, many larvee were almost ready for trans-

forming into pupæ but only a few pupæ were found. Gnats had

emerged from all the galls examined June 3. I kept some of

the galls gathered in December and on subsequent dates, to

watch for transformations. From those of December 26, ine or

No. 468.] THE. WILLOW CONE GALL. 865

two gnats emerged about the middle of February. From those

of March 20.several gnats emerged early in April. From the

April specimens they began to appear within a week and con-

tinued to emerge for over three weeks. Because of the difficulty

in rearing gall gnats my data are not complete. But it is evi-

dent that the insect exists for a long time in the larval state and

that thé pupal period is comparatively short.

Walsh found it difficult to devise an artificial mode of treat-

ment for rearing the gall gnats in the house. My results with

2 MO M Le iE

Fi. 3.— Gall gnat (Rabdophaga strobiloides O. S.) enlarged.

the earlier lots of galls were not very successful. At first I

threw them in jars and boxes but found that in a short time

larvae and pupz dried up in many of the galls. Then I tried

keeping them with the stems in water but with scarcely: better

success. With the last lot I used a different plan. 1 tied the

galls in squares of cheese cloth, opening the bundles and sprink-

ling them every day or two. This plan was very successful.

Of course it is possible that the season had something to do

with it, for it was nearly the regular time for the emerging of

the gnats. But that cannot be the full explanation, for, in pack-

ages which were neglected, the results were less satisfactory.

The sprinkling seems to have taken the place of the spring

showers. | ;

Cecidomyiids offer considerable difficulty in the matter o

866 . THE AMERICAN NATURALIST. | (Vor. XXXIX.

specific determination. Walsh has called the maker of each of

the fifteen willow galls he describes a distinct species. If the

galls themselves could be taken as a means of determining spe-

cies his results would in most cases stand. Although I have

been working with only a few of the cone galls, it is necessary

to consider some others in settling this question.

Of Walsh's fifteen willow galls, six are more or less cone-

shaped bud galls of somewhat similar structure. The larvae

found and described by Walsh in these six are precisely alike as

to size, shape, * breast bone," etc. Walsh gives, however, the

following differences in the cocoons : —

Cecidomyia salicis brassicoides, cocoon scarcely larger than

larva.

Cecidomyia salicis strobiliscus, cocoon 1} to 2 times as long

as larva.

Cecidomyia salicis gnaphaloides, cocoon 1} to 2 times as long

as larva.

Cecidomyia salicis coryloides, cocoon 2 times as long as larva.

Cecidomyia salicis strobiloides, cocoon 2} to 3 times as long

as larva.

Cecidomyia salicis rhodoides, cocoon 21 to 3 times as long as

larva. ; ;

The difference seems to be considerable but it is easily

explained. I have examined all except the fourth (coryloides),

ten or more galls of each, and have found the length of the

cocoons to vary in the different galls in proportion to the length

of the central cell or cavity (see Fig. 5). The gall S. drassicoides

has a short cell which permits of only a short cocoon, while the

gall S. strobtloides has a long central cell giving plenty of space

for a long cocoon. If the cocoon is exuded from the larva and

is expanded by a gas, as Walsh supposed, then the length and

size of the central cell certainly would determine the size of the

cocoon.

In these same six species Walsh found the pupæ of only five.

The only difference I can find in his descriptions is that C. s.

gnaphaloides (in dried specimens) is slightly shorter than the

others. I could not find this difference.

From a careful comparison of ' Walsh's descriptions and from

No. 468.] THE WILLOW CONE GALL. 367

verifications by observation in the case of the cocoons of five of

the galls and in the case of the larvae and pup of three of them,

I am convinced that specific differences, if any, must be looked

for in the imagoes, for they cannot be found in the earlier stages.

Imagoes of the makers of five bud galls were found and

described by Walsh. I give below a table showing the differ-

ences which he finds in them.

Imagoes of Bud Gall Makers.

strobiloides | strobiliscus | gnaphaloides | — rhodoides

Species brassicoides |

Antennal |

oints 22-24 | 21-22 23-24 21-25

Thoracic Hairs Dusky | Whitish Whitish | Whitish Whitish

Length in

nches | 0.16-0.20 |0.16-0.20 | 0.12-0.15 | 0.16-0.20

Origin of Ante- | Occasion- Always ob- | Rather Rather | Occasionally

rior Branch of | ally obso- | solete for a | distinct distinct obsolete

Cubital Wing lete | short space

Vein

The variation in the number of antennal joints makes that

feature useless as a specific characteristic. Antenne of dried

specimens are easily broken, but by using fresh and alcoholic

specimens, I find that there are about the same number of joints

in those of all the gnats which make the different galls.

The color of thoracic hairs is the first and only distinguishing

characteristic. I have had only five imagoes of C. s. brassicoides

Walsh but find that the dusky hairs are present in all, while in

the gnats from the four other galls the thoracic hairs are whitish.

Length shows no difference except in the one case, and I

think this cannot be considered for I found four, from one.lot

of five imagoes from the gall S. gnaphaloides, which were fully

0.21 inches in length, and I have found but one or two as short

as 0.12 inches.

As to wing venation the wings of four C. s. brassicoides Walsh

have the origin of the anterior branch of the cubital vein dis-

tinct. Seventeen left and eighteen right wings of C. s. strobi-

loides Walsh gave the following results as to the origin of the

anterior branch of the cubital vein : —-

868 THE AMERICAN NATURALIST. [Vor. XXXIX.

Origin of 16 anterior veins obsolete.

Origin of 6 anterior veins very indistinct, probably obsolete.

Origin of 4 anterior veins indistinct, probably not obsolete.

Origin of 9 anterior veins distinct.

These results do not agree with Walsh's statement but, on

the contrary, show that this feature of the wing venation cannot

be taken as a specific characteristic. Wings of five C. s.

gnaphaloides Walsh and two C. s. strobiliscus Walsh have the

origin of the anterior branch

very distinct. Four C. s. rho-

Ras doides Walsh show it “ occa-

sionally obsolete” as given by

Walsh. The fact that varia-

tions do occur and that each

of the so called species has

some individuals with the

venation like that of other

Fic. 4.— Wing venation of gall gnat. Cw,, Ante- species is sufficient to throw

rior branch of cubitus. I. Origin distinct II. : A.

Origin obsolete. this out as a determining char-

acteristic. Walsh says him-

self that the imagoes of his gnaphaloides and rhodoides are

indistinguishable except for size, and I have shown that this

difference is not fixed.

His drassicoides differs from the others in having dusky

instead of whitish thoracic hairs.

have had showed this same difference, it is necessary, at least

until other material is available, to let C. &rasszcoides stand as a

distinct species. But from the data I have given and from the

comparison I have made of Walsh's descriptions with each other

ps with my specimens, I must conclude that strobiloides, strobi-

liscus, gnaphaloides, and rhodoides are synonymous. Since the

first name was given by Osten Sacken in 1861, I have taken it

as the name of the species and the three others as synonyms.

So the gnat which produces the four galls, Salicis strobiloides,

— Strobiliscus, Salicis &naphaleides, and Salicis rhodoides

Sua aieo 0:57 TAB verifies the inference of

ue -Ow that Walsh’s species are all strobzloides.

Summarizing, Khabdophaga strobiloides O. S. produces : gall

Since the few specimens I

No. 468.) THE WILLOW CONE GALL. 869

Salicis strobiloides on Salix cordata; gall Salicts strobiliscus on

Salix bebbiana ; gall Salicis gnaphaloides on Salix bebbiana , gall

Salicis rhodoides on Salix humilis.

GUESTS AND PARASITES.

While I was gathering material for the study of the gall gnat

I bred as many as possible of the other insects which inhabit the

galls. These include not only the inquilines and the transient

guests, but also a number of parasites which live on these inqui-

lines or on the gall maker.

In making my table of results I have included a few species

bred by Professor J. G. Needham from cone galls and from the

galls S. rhodoides and S. brassicoides during the spring of 1904.

List of Insects bred from Galls.

Ss = 3 2

ifii

ulws[^|^? 4

5/5| 5/5] 5

Gall maker.

Rha ARAS strobiloides O. S. X|X|X|X

Án jephage brassicoides Walsh x

Inquilin

Cecido omyia albovittata Walsh n X|X|x

aitophorus sp. (plant louse) Bu (qiu dU do a

Pontania pisum sh (saw fly) . - ME

Euura noda Walsh (saw fly X xXx.

Xiphidium ensiferum, eggs miado grasshopper). MUTEX

spring-tail (Thysanura) : XXIX

Acleris d en. (a moth) : x

Larvz of a Noctuid ( set ipi 3 XIX

Larva of Tineid m (Lepidoptera) x

Larva - Thyridopteryx ephemeraformis e (Lepidop- :

Parasites and h perparasites :

Te cs p pd X|x x

Tetrastichus sp ve iie X|x x

Tetrastichus Sp. x x

Polygnotus vafa even Ashm. (a Proctotrupid) KIX x<

Eurytoma studiosa = " (a Chalcıd) X|xX x

Pteromalus sp. (a ci x x

Torymus popenoi Nes gr Chalcid) . A x x

Aphanogmus virginiensis Ashm. : XIX

870 THE AMERICAN NATURALIST. | [Vor. XXXIX.

Lists of Insects bred from Galls. ( Continued.)

2 N w S

3 E 3

$j $|3 i

$|i i| 3|

| E E

Aphelinus mytilaspidus Le Baron (a scale parasite). x | x

A CANONUM in an es) aa ani cee. |

An Encyrtine j | x

‘opidosoma intermedium How | x x

Urogaster forbesii Ash LM

Tridymus metallicus Ashm | x

Dapanus n. ed (an n Ichneumonid) | X

Oncophane. sp. (a Braconid) | X

‘Transient and accidental acne |

Megalothrips sp. | X

Phleothrips sp. |X

Ischnorhynchus reseda Panzer (Heteroptera) | X

Triphleps —— ee RAS er jak : | x

A pseudoscorpioı | x

Thus we find at least 32 species of insects making use of the

cone galls. Of these, one is a gall maker, 10 are inquilines, 16

are parasites or hyperparasites, and 5 are transient or accidental

guests. It will be noticed that the greater number are from S.

strobiloides, which may be due to the better protection offered

by the dense pubescence. The larger insects were more numer-

ous than small ones in S. guaphalotdes.

The following description of the moth bred from the gall S.

gnaphaloides has been furnished for publication in this paper by

Professor C. H. Fernald : —

Acleris heindelana Fernald n. sp.

Expanse of wings, 15-17 mm. Head, thorax, and fore wings dull steel

gray, the wings with a trace of light brown stain below the large triangular

dark brown costal spot which extends from the basal third to near the

outer fifth of the costa and about halfway across the wing. This spot has

minute scattered tufts of blackish scales over the surface and there are also

a few other blackish scale tufts in places common to the species of this

genus.

No. 468.] THE WILLOW CONE GALL. 87 I

Fringes concolorous with the adjoining surface of the wing. Hind wings .

pale gray with a silky luster, a little darker at the apex, and with the fringes

of the same color as the base of the wings. Under side of the fore wings

much darker than the hind wings and with the costa marked alternately with

light and dark gray. The hind wings are sprinkled with brown dots towards

the apex. Abdomen of the same color as the hind wings.

Described from two female specimens: one from Lake Forest, Ill., and

one belonging to the U. S. National Museum and taken in Winnipeg,

Manitoba, by A. W. Hanham.

I have one specimen in rather poor condition which may possibly belong

to this species. It is labeled as follows: * Ft. Klamath, Ore., 10.6. "86.

Eggs of the meadow grasshopper (A7phidium ensiferum) were

found in both old and recent galls. In many cases they were

dried up. The grasshoppers began to appear in May. Wheeler

says that the meadow grasshoppers seem to prefer the blackened

and weatherbeaten galls, probably because their scales are more

easily forced apart. He believes that this insect’s habit of put-

ting its eggs in the galls is of comparatively recent acquisition

because in some cases the eggs are poorly placed and because

the insect still uses galls whose scales are so close together as to

flatten and kill the eggs,, evidence that the grasshopper has not

learned to distinguish the kind of gall best adapted to its pur-

pose. If we accept Wheeler’s conclusion, we may say that the .

gall is of increasing importance to the insect world.

So far as is known, Tetrastichus is hyperparasitic. There

are numerous undescribed species which are difficult to separate.

Polygnotus salicicola was bred from a Cecidomyiid leaf gall

of the willow by Mr. A. Koebele at Los Angeles, Cal.

Mr. Theo. Pergande says that both of the thrips, Megalo-

thrips and Phloeothrips, are apparently undescribed.

Ischnorhynchus resede Panzer is a common European species,

also common in the United States. Triphleps insidiosus Say is

a common and widespread species found upon berries and upon

the ox-eye daisy.

Although it is difficult and often impossible to identify the

various insects in their larval state, still an early examination is

of value for showing the abundance of life in the individual galls.

Usually the larva of the gall gnat which is the maker of the gall,

872 THE AMERICAN NATURALIST. (VoL. XXXIX.

is present in its central cell. It is easily recognized, not only

by its larger size, but especially by the presence of the ‘breast

bone" so characteristic of all Cecidomyiid larvae. Larve of

small Cecidomyidz are found in considerable numbers between

the outer scales of many galls. These are also recognized by

the * breast bone" but with

greater difficulty because of

their smaller size.

Twenty-three 1904 pubes-

cent galls from the region of

Pettibone Creek, north of

Lake Bluff, Ill., gathered and

examined in October, 1904,

contained fifteen living and

two dead larve of the gall

gnat which produces the gall

(6 galls were without Rhab-

dophaga larva), 169 small

Cecidomyiid guest larva, 6

larvae of Hymenopterous para-

sites of which two were in the

central cell of one gall in place

of the Rhabdophaga larva,

and 384 meadow grasshopper

eggs. One 1903 gall from the

same place contained 16 grass-

hopper eggs.

larva in a burrow; e, eggs of Xiphidium ensife- from South Wayne, Wis.,

rum; f, larva of Hymenopterous parasite. gathered December 26, 1904,

contained 9 larve of gall

gnats, I guest Cecidomyiid about half as long as the gall maker,

37 smaller Cecidomyiid larva, 2 parasitic larvae, and 13 grass-

hopper eggs. Six 1903 galls from same place contained 32

grasshopper eggs.

Seventeen 1904 crooked-stem galls from west of Lake Bluff

Ill, gathered January 17, 1905, contained ten larvz of the gall

maker, 28 Cecidomyiid larvae about half as large as maker, 10

No. 468.] THE WILLOW CONE GALL. 873

smaller Cecidomyiid larve, 5 saw fly larvze, 13 larve of Hymen-

opterous parasites, and nearly 400 grasshopper eggs. Three

1903 galls from same place contained 3 saw fly larvae and about

125 grasshopper eggs.

I can conclude with no more appropriate words than those

which Walsh used in connection with another gall: *If this one

little gall and the insect which produces it were swept out of

existence, how the whole world of insects would be convulsed as

by an earthquake! How many species would be compelled to

resort for food to other sources, thereby grievously disarranging

the due balance of insect life! How many would probably

perish from off the face of the earth, or be greatly reduced in

numbers! Yet to the eye of the common observer this gall is

nothing but an unmeaning mass of leaves, of the origin and his-

tory of which he knows nothing and cares nothing ! "

BIBLIOGRAPHY.

VON BERGENSTAMM, J. E., AND Löw, P.

"76. Synopsis Cecidomyidarum. Verh. zoöl.-bot. Gesellsch. Wien, vol.

26, pp. I-104.

Cook, M. T.

:03. Preliminary List of IRRE Insects Common to Indiana.

Ohio State Naturalist, vol. 4, pp. 104-106.

OSTEN SACKEN, C. R.

'58. Catalogue of the Described Diptera of North America. Smitson-

tan Misc. Coll., vol. 3, 112 pp. _

SPEISER, P.

:03. Wie die jungen Weidenbäume den Angriff der Dichelomyia rosaria

H. Lw. unshädlich machen. Allgem. Zeitschr. f. Entomol., vol. 8,

pp. 204-206.

WALSH, B. D.

'64. On the Insects, Coleopterous, Hymenopterous, and Dipterous,

Inhabiting the Galls of Certain Species of Willow. Proc. Phila.

Entomol. Soc., vol. 3, Pp- 543-644, vol. 6, pp. 223-288.

WarsH, B. D.

'69. Galls and their Architects Amer. Entomol., vol. 2, pp. 45-50, 70-

74, 103-106.

Vh Å

nave aes

^ n

—

EINER RU XN

FOREST CENTERS OF EASTERN AMERICA.

EDGAR N. TRANSEAU.

AN examination into the distribution of the forest trees of

eastern North America develops the fact that there are several

natural vegetation centers. Adams (: 02) called attention to the

AT.

V7 Vel

Abies

Fic. 1.— Map showing distribution of several of the dominant Conifers of the N

» g * Li

Conifer center. The relative intensity of shading indicates the relative number of species

found in the region.

distinctness of the biota of northeastern and of southeastern

America, and showed that they are to be regarded as centers of

875

[Vor. XXXIX.

Within its limits,

the plants have a wider range of habitats, attain a greater size,

It is also shown that.

In a former paper the writer

THE AMERICAN NATURALIST.

(103) pointed out that if the distribution of the characteristic

bog plants be plotted on a map, the Laurentian region of Canada

is indicated as their center of distribution.

and are more abundant than elsewhere.

dispersal for the fauna and flora.

876

Mess B

FEN EL

CORN N =

LEE

KE?

rte

I e Cartadensis

LED

oer

i PLLA

I ROLLER

H "SS EER

i RRA

en N RER

à CU TLA

EEP 3 d QoS ED

VET ICE OIA

E ORE ese

Q EEE A

C TILA

= [27^ Ree COKER RR

ELAR LRA

T EEE

DKL PLAID

af nto o PUER

ORIEL A TRE le

ALLRLIR? 7 OOOH)

ROW LO

ORT a RLF

BOQ ORGIES A

D^ OLE d Dt. E

ROI

P3 3S zs

EOIN S

Teg C EN

‚the bog

plants range

f hi

persal

Dr. P. A. Rydberg,

8e, while the herbaceous

XICO,

canadensis, Acer Bennsylvanicum, Betula papy-

ssor Aven Nelson,

bligations to Profe

Ka 3 S

IC seas to the Gulf of Me

species are most limited in extent of d

rifera, Prunus Pennsylvanica,

center. The writer is under o

ave a wider ran

Fic. 2.— Map showing distribution of Picea

and Mr. W. P. Holt for

the tree

shrubs h

from the Arct

No. 468] AMERICAN FOREST CENTERS. 877

In using the term * center of distribution " it is not implied

that the plants have necessarily spread from these centers, but

that the complex of climatic factors most favorable to the devel-

opment of this type of vegetation is here localized, and that as

we depart from such centers we find conditions more and more

unfavorable. This implies the elimination of. such species as

are most rigidly dependent upon definite conditions. Compare

for example (Fig. 1) the distribution of Pinus strobus and Tsuga

canadensis with that of Picea mariana or Larix laricina and

note the intermediate dispersal of Adzes balsamea. | Fig. 2 shows

the distribution of several other species and still further rein-

forces the suggestion that the St. Lawrence basin is a definite

center about which is distributed a unique type of forest. It is

floristically related to the forests of other parts of the continent

but ecologically and climatically it is distinct.

The recognition and separation of these centers is of the

greatest importance at the present time when there is so much

activity along physiographic ecological lines. That there is a

natural succession of plant societies in a given locality has long

been recognized. Cowles (:o1a) has shown that this succession

may be correlated with the physiographic development of the

region, because soil structure, water content, and slope are

largely determined by it. Already the applicability of this

hypothesis has been demonstrated in many parts of the United

States.

But thus far little attention has been paid to the relation

which the successive plant societies found in an area bear to

their centers of distribution. In other words, the societies have

been studied from their physiographic, but not from their geo-

graphic aspect. Such a geographic outlook, however, not only

aids in the selection of the characteristic plants of the local hab-

itat, but also throws light on the relative importance of the sev-

eral societies. The geographic point of view is also necessary

to furnish a suitable basis for comparing local meteorological

data. Unless the climatic conditions of the centers of distribu-

tion of the societies are pointed out, the meaning of local climatic

data is not apparent. ` Further, it is probable that in many areas

the societies are not all members of the same geographic center,

878 THE AMERICAN NATURALIST.. [Vor. XXXIX.

so that comparisons with the conditions in two or more centers

may be necessary to interpret fully the local data.

The geographic point of view is of the greatest importance in

the study of regions intermediate between the great plant for-

mations. In such localities there is a mingling of both species

and societies which have spread from very different distribution

centers. The local order of succession is usually a mixture of

two or more orders, characteristic of as many centers. For

example, in northern Michigan the successive societies (Whit-

ford, :01) in the development of the forests, are: (1) xerophi-

lous herbs, (2) the heath, (3) the coniferous forest, and (4) the

maple-beech climax forest. While there can be little doubt but

that this is the correct interpretation of the forest relationships

in this region, there is a notable difference between these socie-

ties. The first three may be found anywhere in that region,

while the last occurs only in areas favored by a rich soil, the

climatic influence of the lakes, and the possibilities of migration

from the southeastern deciduous forest. The first three socie-

ties are stages in the development of the climax forest of the

Northeastern Conifer forest center, the last is the attenuated

border of the climax stage of the southeastern Deciduous forest

center. The first three stages are largely physiographic, while

the last is also geographic, for it marks not only the succession

of one society over another, but also the invasion and succession

of one forest center over another.

In northern Pennsylvania and part of the mountains of New

England, it appears from preliminary work that the successional

relationship of the societies can only be traced by taking into

account the fact that the societies of northern slopes and certain

other edaphic situations are related to the Northeastern Conifer

forest and form an order of succession distinct from that to

which the societies of southern slopes and other favored situa-

tions belong.

Where best developed in the lower Ohio basin and Piedmont

plateau, the climax stage of the Deciduous forest center (Fig. 3)

is made up of many species of which the dominant are Quercus

alba, Magnolia acuminata, Acer saccharum, Fagus americana,

Liriodendron tulipifera, Fraxinus americana, Quercus rubra, and

No. 468.] AMERICAN FOREST CENTERS. 879

Hicoria alba. Of these species the most hardy are the beech

and the maple. In many places in the northern states the latter

occupies areas almost to the exclusion of other trees, while

within the southeastern center it is only one of many species in

ie up ni

f i

Ts "A =

| AES

l? EX

ui 9: 54946457.

49e. NE a

SLRS SSRIS”

uy KY . WO

J Beene Keo nas SEELE

er ORSA te 37 ERS

= FR IE Sete!

KS Rei Wy

2% DU

OOK

jw, %

KORE >

ox Be KS " <

T en —

ara Rx D

PRR

RXR

SOD

RER

PRIOR)

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bd »

i -

A E

t &

T uL ai Foe po Jg HUN e 7 TRS oF pate = ie tage of the id-

IG. 3.— Map s Dec

;—— —— ——, Fraxinus americana,

uous forest center. ---7-7^» Acer saccharum ; , Fraxi ;

7 ie De aiia, comm» Magnolia acu-

——.—— - Fagus americana, ——

minata; ———, Liriodendron tulipifera.

the forest. This may be explained, not by the statement that

the maple is a northern tree, but by the fact that its shade-

enduring and shade-producing properties find no worthy com-

petitor among the trees of the Northeastern Conifer formation,

while at the south it is one of many species having the same

characteristics. ; |

of the southern Appalachians there is

In the mountain region

880 THE AMERICAN NATURALIST. [Vor. XXXIX.

an extension of the Northeastern Conifer forest. Probably it

should be regarded as a subcenter, because of the large number

of endemic forms present, and because many other species there

attain their greatest development. There, it has been shown

(Cowles, : o1b) that the pine stage is followed by an oak society,

which in turn gives way to the climax deciduous forest. This

seems to correspond with the succession in certain parts of the

Q^ | } NS P

2 ES. |

j jo

cys. ges

m yy"

PEN > 2 TJ

; echinata

d -

(ue \ ; d ‘Pinus taeda

1 1 2E " Se

x : i oe : Pinus palustris}

N Pinus heterophylla

nn A Y a x Pinus glabra

b ; Pinus glabra

“Pinus echinata

i-a Chamaecyparis thyoides

N “Pinus tae

Pinus taeda n

Pinus palustris”

* v an

eade

Fic. 4.— Map sho

wing distribution of several trees belonging to the Southeastern Conifer

forest center, Ch paris thyoides i inih oat ; the pi

Ath th ti

es,

f Pinus glabra, belong to the climax forest.

lower peninsula of Michigan, where the pines and the oaks both

occur. Both localities are intermediate between the same two

forest centers, and such a correlation is to be expected. The

earlier stages in the succession are dominated by the Northeast-

ern Conifers, while the last two are parts of the Deciduous

forest center. |

Furthermore in such intermediate regions, we may find two -

No. 468.] AMERICAN FOREST CENTERS. 881

distinct societies occupying the same or similar habitats. For

example, in southern Michigan, the xerophilous bog societies

and the hydrophilous swamp societies are so related. The

former, however, are a part of the Northeastern Conifer forest,

while the latter belong to the Deciduous forest succession. Con-

sequently, where the bog societies are surrounded by oaks they

à d. | 3 pe AM D

- um S .

agnolia

f » lauc

Populus

uf 4 ET heterophylla

r h te & E t

> Myssa

ze me : aquatica

Magnolia foetida

S Ai: 4s Populus heterophylla

: Nyssa aquatica

Magnolia glauca $e 7 A)

Magnolia foetida `

$ o

Q.Texana D b

+h as

= + fxh. th + Conife:

IG. &. a p p ere g pt Conife

a center. Magnolia glauca, M. fætida, Nyssa aquatica, Populus heterophylla, Taxo-

dium distichum, and Quercus texana.

bear no successional relationship, while the swamp societies

change gradually into the oak and climax stages of the Decidu-

ous forest. In such cases the geographic considerations are of

equal importance with the physiographic, for the proper classifi-

cation of the plant societies.

Turning to the coastal plain of the southeastern states, we

find a dominant forest of Conifers, with mixed Conifer ; and

broad-leafed societies on the low grounds. Here slight differ-

882 THE AMERICAN NATURALIST. | [Vor. XXXIX.

ences of elevation and relative geological age tend to be strongly

expressed in the vegetation (Pinchot and Ashe, '97, pp. 143-181 ;

Mohr, :otr, pp. 107-133; Harshberger, :04, pp. 611-614).

The Conifers probably represent the climax forest of this for-

mation. The distribution of certain of its components is shown

in Figs. 4 and 5. Several other associations of shrubs and

trees might be similarly depicted and still further emphasize the

identity of the Southeastern Conifer forest center. As shown

by the accompanying maps and the descriptions of Smith, and

Pinchot and Ashe, there is a mingling of societies of this center

and of the Deciduous forest, in the region of the Piedmont

plateau, which tends to obscure the recognition of the stages

properly belonging to each.

On the southern half of the Florida peninsula is a fourth

formation, made up largely of xerophilous tropical species. It

really represents the northern border of a center which domi-

nates the West Indies and tropical America. It may be desig-

nated the Insular Tropical forest center.

There appear then to be four centers of distribution in eastern

North America: (1) the Northeastern Conifer, (2) the Decid-

uous, (3) the Southeastern Conifer, and (4) the Insular Tropi-

cal. Each is made up of many societies, which bear a definite

successional relationship to one another.

With the exception of the tropical, each of these formations

has its western border marked by gradation into the grasslands

ofthe Great Plains. The local flora of any part of the interme-

diate prairie region is composed of societies from the plains and

the adjoining forest centers. For example, take the succession

of plant societies on the bluffs of the Kansas River in eastern

Kansas. The pioneer society is made up of Bouteloua hirsuta,

Mentzelia oligosperma, Euphorbia marginata, E. dentata, E.

petaloidea, Bebera papposa, Artemisia ludoviciana, Aster sericeus,

A. fendleri, Megapterium missouriense, Tragia ramosa, Baptisia

bracteata, B. australis, Lacinaria punctata, Croton texensis, Solt-

dago missouriensis, and Silphium laciniatum. This society be-

longs to the flora of the Great Plains and has its eastern limit

in the prairie belt. The shrub stage following this is made up

principally of Symphoricarpos symphoricarpos, Ceanothus ovatus,

No. 468.] AMERICAN FOREST CENTERS. 883

Rhus glabra, R. aromatica, R. radicans, Cornus asperifolia, C.

amomum, and Xanthoxylum americanum. This society is of

very different origin and represents the western border of the

shrub stage of the Deciduous forest formation. The shrubs are

succeeded by trees belonging to the same center, among which

are Juniperus virginiana, Ostrya virginica, Celtis occidentalis,

Quercus acuminata, Cercis canadensis, Ulmus fulva, etc. A

very different combination of societies would be met with in

similar situations in northwestern Minnesota or southeastern

Texas because of the different centers involved.

The mapping of these centers naturally brings up the question

of the climatic determinants of each. During glacial times the

Northeastern Conifer must have been mixed with the Decidu-

ous forest. Why are they so distinctly separated at the present

time? What are the causes of the * prairie peninsula " in Iowa,

Illinois, and Indiana; and the region of open forests adjoining it ?

Naturally we look for some method of mapping climatic data,

which will show climatic centers in approximately the same

positions as the centers of plant distribution. An examination

of monthly, seasonal, and annual temperature and rainfall maps

shows that neither of these factors alone can do this. Historical

considerations may aid in explaining the relative positions of these

centers, but are inadequate for the complete explanation of their

present limits.

A method was accordingly sought by which temperature and

moisture data could be combined in a single number. The fact

that so large a part of all plant adaptations is directly or indi-

rectly connected with transpiration, suggested that if the ratio

of the rainfall to the evaporation were determined, a new basis

for mapping would be at hand which would involve several cli-

matic factors. The depth of evaporation depends upon (T. Rus-

sell, '88) the temperature of the evaporating surface, the relative

humidity of the air, and the velocity of the wind. These are the

same climatic factors which most powerfully affect transpiration,

and which must be of great importance in determining the geo-

graphic range of plants. Unfortunately, the only figures for evap-

oration available are those published by T. Russell for the year

beginning July 1, 1887, and extending to July ı, 1888. They

884 THE AMERICAN NATURALIST. | [Vor. XXXIX.

represent the possibilities of evaporation from a free water sur-

face inside the instrument shelters. Just as the figures for the

rainfall do not represent the amount of water actually available

for plants (since it includes the run-off, the part that evaporates,

and that which sinks into the ground) so the figures for evapora-

tion do not correspond to the water vapor actually given off by

plants, because this is determined largely by the ecological adap-

tations of the individual plants. But the figures have a compara-

tive value in both cases and when combined probably give a fairly

correct idea of the distribution of these climatic factors in the

eastern United States. The map was not extended to the west-

ern states owing to the paucity of data and the disturbing influ-

ence of the mountains. However, sufficient evidence is at hand

to show that a desert center is clearly indicated in southern

Arizona and California, and a forest center in the Puget Sound

region. A comparison of the data for Colorado Springs and

Pike's Peak indicates that the ratio increases from about 20 per-

cent to 100 percent as one goes from the base to the summit of

the Peak. This suggests the importance of taking other factors

than temperature into account when explaining the distribution

of the forests on mountains.

Turning now to the map (Fig. 6) showing the distribution of

the rainfall-evaporation ratios in the eastern states, it will be

noted that the Great Plains are marked by a rainfall equal to

from 20 to 60 percent of the evaporation called for. The

prairie region where forests are confined to the low grounds, is

indicated by a ratio of from 60 to 80 percent. Its limits as in-

dicated show a remarkable agreement with the actual distribu-

tion of the prairie. The region indicated by ratios between 80

and 100 percent is more or less coincident with the occurrence

of “oak openings," “open forests," and “groves” on the up-

lands, and dense forests on the low grounds.

The southeastern area where the rainfall is from 100 to 110

percent of the evaporation, corresponds to the region of the

Deciduous forest center. The distribution of the ratios above

IIO percent in the region of the coastal plain is remarkably

similar to the position of the Southeastern Conifer forest center.

No. 468.] AMERICAN FOREST CENTERS. 885

In the southern Appalachians the ratio also rises above 110 per-

cent and coincides with the occurrence of the southern exten-

sion of the northeastern forests. No data are available for the

mountainous parts of Pennsylvania, so that this apparently iso-

lated area may be climatically connected northward along the

ER,

= 80%

: N

um M

Fic. 6.— Map showing ratio of rainfall to'evaporation expressed in. percentages. (Compare

with Sargent's map of the “ Forests of North America," roth Census Report.)

higher mountain crests. The Northeastern Conifer forest center

is marked by ratios above 100 percent and centering in the St.

Lawrence basin. It is probable that the northern limits of this

formation will not be indicated by the rainfall-evaporation ratios,

for the factors commonly accepted (Schimper, : 03, p. 168) as

determining the northern limits of forests are very different from

those causing the boundaries of other formations. It should

886 THE AMERICAN NATURALIST. (Vor. XXXIX.

also be stated that since climates are constantly changing and

effects may lag far behind their causes, no map of present cli-

matic conditions can hope to do more than approximate the

present distribution of plants. Geographic and historical rela-

tions must be constantly borne in mind.

SUMMARY.

It may be stated, by way of summary, that eastern North

America is occupied by four great forest centers: (1) the North-

eastern Conifer forest, centering in the St. Lawrence basin, (2)

the Deciduous forest, centering in the lower Ohio basin and

Piedmont plateau, (3) the Southeastern Conifer forest, centering

in the south Atlantic and Gulf coastal plain, and (4) the Insular

Tropical forest of the southern part of the Florida peninsula,

centering in the West Indies. The term center as here used,

implies the idea of distribution about a region where the plants

attain their best development: Such vegetation divisions are

not fixed, but move and increase or decrease in extent depending

upon continental evolution and climatic change.

Each formation is made up of many societies, bearing a defi-

nite successional relationship to one another, which being

dependent upon soil factors may be best correlated with phy-

siographic changes. In regions intermediate between centers,

the local order of succession is made up of societies from each

of the adjoining formations. j

It has been found that if the ratios produced by dividing the

amount of rainfall by the depth of evaporation for the same

station, be plotted on a map they exhibit climatic centers which

correspond in general with the centers of plant distribution.

Further, the distribution of grassland, prairie, open forest, and

dense forest regions is clearly indicated.

This is explained by the fact that such ratios involve four

climatic factors which are of the greatest importance to plant

life, vzz., temperature, relative humidity, wind velocity, and

rainfall.

ALMA COLLEGE. ALMA. MICH.

No. 468.] AMERICAN FOREST CENTERS. 887

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ADAMS, C. C.

:02. The Southeastern United States as a Center of Geographical Dis-

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ADAMS, C. C.

:05. The Postglacial Dispersal of the North American Biota. Read at

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BEAL, W. J.

:04. Michigan Flora. 5th Ann. Rep. Mich. Acad. Sci., 147 pp.

— C. E.

The Forests and Forest Trees of Nebraska. Ann. Rep. Neb. State

Bd. Agric., p. 79.

BisHoP, J. N.

:01. Catalogue of Phaenogamous and Vascular Cryptogamous Plants of

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:01. Manual of the Flora of the Northern United States. Henry Holt

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CLARK, A. M.

’99. The Trees of Vermont. Contributions to the Botany of Vermont,

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COULTER, S.

'99. Catalogue of the Flowering Plants and Ferns of Indiana. 2474

Ann. Rept. Dept. Geol. Ind., p. 553.

CowLES, H. C. :

:01a. Physiographic Ecology of Chicago and Vicinity. Bot. Gaz., vol.

31, P. 145.

CowLEs, H.C.

:Olb. Influence of Underlying Rocks on the Character of the Vegeta-

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HARSHBERGER, J. W.

The Comparative Age of the Different Floristic Elements of East-

ern North America. Proc. Acad. Nat. Sci. Phila., 1904, p. 601.

Harvey, L. H.

: 03 A Study of the Physiographic Ecology of Mt. Ktaadn, Me. Univ.

of Me. Studies, no. 5.

HINCKLEY, F. C.

'99. Notes on the Animal and Vegetable Life of the Region of the

888 THE AMERICAN NATURALIST. | (Vor. XXXIX.

Sushitna and Kuskokwim Rivers, Alaska. 20th Ann. Rep. U. S.

Geol. Surv., vol. 7, p. 77.

KEARNEY, T. H

The Line Austral Element in the Flora of the Southern Appala-

chian Region. Science, n. s., vol. 12, p. 830.

PPLE AN, W.A.

The Fourth State Catalogue of Ohio Plants. Ohio State Univ.

Bull., ser. 4, no. 10.

KIMBALL, H. H

:05. Evaporation Observations in the United States. U. 5. Weather

Bur. Bull., no. 327.

LIVINGSTON, B. E.

03 e Distribution of the Upland Plant Societies of Kent Co.,

Michigan. Bot. Gaz., vol. 35, p. 36.

MACOUN, J. i

'83. Catalogue of Canadian Plants. Pts. 1 to 3. Geol. and Nat. Hist.

Surv. Canada.

Macoun, J. M.

'95. Contributions from the Herbarium of the Geological Survey of

Canada. Can. Rec. Sci., vol. 6, Apr.

Mason, S.C.

'92. Preliminary Report upon the Variety and Distribution of Kansas

Sth Ann. Rep. Kans. State Bd. Agric.

MENDENHALL, W. C.

:02. Reconnaissance from Fort Hamlin to Kotzebue Sound, Alaska.

Prof. Paper, U. S. Geol. Surv., no. 10, p. 58.

MERRIAM, C.H.

'91. Distribution of Life in North America, with Special Reference to

the Mammalia. Smithson. Rep., 1891, p. 365.

MORR, C.

'97. Timber Pines of the Southern United States. Div. of Forestry,

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MonR, C.

:01. Plant Life of Alabama. Geol. Surv. of Ala.

PiNcHOT, G., AND AsHE, W. W.

'97. Timber Trees and Forests of North Carolina. JV. C. Geol. Surv.,

bull. 6.

PORTER, T. C.

:03. Flora of Pennsylvania. Ginn & Co., Boston.

RUSSELL, T.

'88. Evaporation. Monthly Weather Review, Sept.

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'96. Flora of the Black Hills of South Dakota. Contrib. U. S. Nat.

Herb., vol. 3, no. 8.

SARGENT, C. S

’84. Forests of North America. roth Census of the U. S., vol. 9.

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SARGENT, C. S.

'91— 02. The Silva of North America. Houghton, Mifflin & Co.,

Boston.

SARGENT, C. S.

:05. Manual of the Trees of North America. Houghton, Mifflin &

Co., Boston.

SAUNDERS, D. A.

'99. Ferns and Flowering Plants of South Dakota. .S. Dak. Agric.

Exper. Sta., bull. 64.

SCHIMPER, A. F. W.

:03. Plant Geography upon a Physiological Basis. Translation by W.

R. Fisher, Oxford.

SMALL, J. K.

:03. Flora of the Southeastern United States. Pub. by the author,

New York.

SUDWORTH, G. B

‚98. Checklist of the Forest Trees of the United States. Div. of For-

estry, U. S. Dept. Agric., bull. 17.

TRANSEAU, E. N.

:03. On the Geographical Distribution and Ecological Relations of the

Bog-plant Societies of Northern North America. Bot. Gaz., vol.

36, p. 401.

VASEY, G.

! The Distribution of North American Forest Trees. U. S. Deft.

of Agric., spec. rep. no. 5, p. 38.

WEATHER BUREAU, U. S. ,

:04. The Record of Weather in the United States. The American

Almanac, p. 77-

WHITFORD, H. N.

:01. The Genetic Development of the Forests of Northern Michigan.

Bot. Gaz., vol. 31, p. 315.

MANDIBULAR AND PHARYNGEAL MUSCLES OF

ACANTHIAS AND RAIA!

GUY ELLWOOD MARION.

INTRODUCTION.

THE following paper deals only with the muscles of the jaw

and branchial region in the common dogfish (Acanthias vulgaris),

and in one of the common skates (Raza erinacea). The existing

literature upon this subject is very scanty, and aside from a

few scattered references to the muscles, I have found only the

detailed papers by Vetter (74) upon the mandibular and bran-

‚chial regions of the sharks, and a similar paper by Tiesing ('95)

who discusses in the same way the muscles of the skates.

Drüner (:03) uses the Selachians in describing the visceral mus-

cles of the Urodeles.

The present article follows very closely the work of Vetter

and Tiesing, especially that of the former. Tiesing classifies

and arranges the muscles upon the basis of innervation; Vetter

upon that of position and function. That the former method

has its advantages is admitted, but convenience leads me to

adopt the scheme of Vetter; and although not agreeing with

him in all points, I have adopted as far as possible his nomen-

clature and lettering of the figures. As was said above, Vetter

deals only with the sharks, and Tiesing with the skates, while

I have tried to draw homologies between the two groups, and

this has led me at times to differ from my predecessors.

The mandibular and branchial muscles may be divided into

four main groups : —

1. Superficial circular muscles.

2. Interarcuales (muscles between the upper ends of the

branchial arches).

3. Adductores (flexors at the middle of the arches).

1 Contributions from the Biological Laboratories of Tufts College, No. XLIII.

891

892 THE AMERICAN NATURALIST. (Vor. XXXIX.

4. Ventral longitudinal muscles.

Each of these in turn contains several muscles which are capa-

ble of arrangement under subordinate headings. In the follow-

ing account, the muscles of one of the major divisions will be

described for Acanthias, and then the corresponding muscles for

Raia.

SUPERFICIAL CIRCULAR MUSCLES.

Of these there are seven groups :—

I. Superficial constrictors; a, dorsal; 4, ventral.

2. Interbranchiales (lying between the walls of the gill

clefts).

3. Levator maxilla superioris (raising the upper jaw).

4. Trapezius (raising the shoulder girdle and drawing it for-

ward).

5. Levator labialis superioris (raises the upper lip),

6. Levator rostri (raises the rostrum). In Raia only.

7. Depressor rostri (depresses the rostrum). In Raia only.

Superficial Constrictors.

Acanthias.

The superficial constrictors are the most external of the mus-

cles which cover the gill pouches and form the surface of ‘the

region of the ‘neck.’ They may be divided, from position, into

dorsal and ventral constrictors and are six in number on either

side. Between them the five gill slits are placed, the first lying

between the second and third, the fifth gill slit occurring behind

the sixth constrictor (Figs. 1, 2). The gill slits are slit-like in

character, about 18 mm. in extent, and are vertical in position,

located near the ventral portion of the side of the body.

Dorsal Constrictors — The first and most anterior dorsal con-

strictor (Fig. 2, Csd 7) takes its origin from the lateral surface

of the cranium just below the posterior end of the dorso-lateral

ridge. Its point of origin is not separated from that of the

levator maxillae superioris, to be described below. Its fibers run

ventrally and forward, curving around the anterior wall of the

No. 468.) MUSCLES OF ACANTHIAS AND RAIA. 893

spiracle in front of the spiracular cartilages, and are inserted

upon the inner surface of the lower jaw just below the *coro-

Ati

DE DL et

Fic. 1.— Ventral muscles of Acanthias after removal of skin. Az, adductor mandibularis ;

Cac, coraco-arcualis communis; Csz 7-6, constrictores superiores ventrales; Csv ra, con-

strictor superioris ventralis, anterior fibers; Gs, gill slits; Z/s, levator labialis superi-

oris; 2, tendon in adductor mandibularis :

noid' process. The general course of the fibers is curved,

while that of the levator maxillae superioris is straight, the only

894 THE AMERICAN NATURALIST. |. (Vor. XXXIX.

feature distinguishing these two muscles, which Vetter does not

regard as separate. I believe that of this common mass of mus-

cles the anterior straight fibers alone represent the true levator

maxillae superioris, while the posterior curved fibers represent a

Fic. 2.— Dorsal muscles of Acanthias after removal of the skin. Am, adductor mandibularis;

Csd 1-6, constrictores superiores dorsales; Lous, levator maxillæ superioris; y, tendinous

mass back of eye; 7' trapezius. :

dorsal constrictor. In this connection Vetter (74, pp. 420-421)

says: “Die beiden Spritzlochknorpeln, welche fast senkrecht

No. 468.] MUSCLES OF ACANTHIAS AND RAIA. 895

zum Faserverlauf dieser Partie nach aussen gerichtet sind, lagern

sich dabei ihrer hintern Fláche dicht an, so dass diese zu den

Spritzlochknorpeln genau in dieselber Beziehung tritt, wie sie

zwischen den Mm. interbranch. und den knorpeligen Radien

des Kiemenbogen, oder zwischen Cs4 2 und Csv 2 und den Radien

des Zungenbeinbogen besteht.”

Vetter has not carried his comparisons far enough. If these

fibers nearest the spiracular cartilages bear the same relation to

these cartilages as do those of the second dorsal and ventral

constrictors to the rays of the hyoid arch, then why do they not

represent another constrictor muscle Csd 7 exactly like Csd 2 in

general relations? By a further comparison with Raia (Fig. 6)

we see that the general course of the fibers of the posterior part

as well as the insertion make this part distinctly comparable to |

the Csd 7 of that form.

The second dorsal constrictor (Fig. 2, Csd 2) is by far the

largest of the dorsal constrictors. It is a wide flat muscle

extending from just behind the spiracle to the first gill slit. In

front it arises from the postero-lateral surface of the cranium,

farther back from the strongly fibrous fascia which completely

covers the dorsal muscles. This origin extends as far back as

the anterior end of the trapezius (Fig. 11) and even beyond that

the fibers send tendinous attachments through the trapezius to

their origin in the main tendinous fascia covering the longitudi-

nal muscles. The first dorsal aponeurosis between the constric-

tors runs from the point where the fibers enter the trapezius in

an obliquely ventral direction to the dorsal end of the first gill

cleft. From this aponeurosis the more posterior fibers of (sd 2

take their origin. The fibers of the muscles run obliquely from

their origin on the dorsal margin of the muscle.

The insertion is also diverse. The most anterior fibers, which

bound the spiracle behind, are inserted at the quadrate end of

the upper jaw. The next fibers run around and cover the hyo-

mandibula and are inserted upon the ceratohyal cartilage. This

portion of the muscle corresponds to the levator hyomandibularis

of Raia, where, attached to the same visceral arch, it has become

much further developed. Beyond this portion the fibers are

inserted upon a tendinous bridge connecting the dorsal and ven-

896 THE AMERICAN NATURALIST. (VoL. XXXIX,

s Y

NV IK

N RAIN

\ | eet

Z um es

| aa

—

FıG. 3.— Ventral view of Raia, the right half 4 deeper dissection than the left. Aml 7, 2,

dd libularis lateralis (superficial layer, posterior) ; A m? 22, adductor mandibu-

laris lateralis (superficial layer anterior); Anm, adductor mandibularis medialis ; Cac, cor-

aco-arcualis communis; CBr, coraco-branchialis ; CZ», coraco-hyomandibularis; CZy,

coraco-hyoideus ; Cw, coraco-mandibularis ; Csv 7-7, constrictores superiores ventrales ;

DH m, depressor hyomandibularis; Dir, depressor mandibularis; /#tbr 7-4, interbran-

chiales; Z/s 7-4, levatores labialis superioris; Zs, levator maxille superioris.

No. 468] MUSCLES OF ACANTHIAS AND RAIA. 897

tralconstrictors. This bridge extends about halfway from the

end of the hyoid arch to the first gill slit. The remaining fibers

pass over into those of the ventral constrictors, forming a con-

tinuous muscle. The fibers follow the direction of the gill slit in

their course.

The remaining dorsal constrictors (three to six) are so closely

similar that one description will serve for all (Fig. 2). The

tendinous aponeuroses between them are somewhat curved, each

ending at the top of a gill cleft and covering an underlying extra-

branchial cartilage. The muscle fibers run nearly vertically and

those attached to the aponeuroses are often also attached to the

extrabranchials. Towards the dorsal margin some of the fibers

converge to a tendon at the posterior edge of the muscle, and

these tendons, after piercing the trapezius (Fig. 11, Csd 2-6),

have their points of origin among the fibers of the dorsal longi-

tudinal muscles, the last being also attached to the shoulder

girdle. The more ventral fibers arise from the aponeurosis

behind each muscle and are in part inserted on the aponeurosis

in front, and in part continuous with the fibers of the ventral

constrictors.

Ventral Constrictors. — The ventral constrictors (Csv) do not

differ markedly from the dorsals, and like them are six in num-

ber. Here I am at variance with Vetter (’74, p. 416) who does

not describe a first ventral constrictor for Acanthias, but begins

with Csv 2. This is, however, clearly the first ventral constric-

tor, while his Csv8 2is really the Csv 2, for if we compare ven-

tral with dorsal sides, we find that the muscle in front of the

spiracle which is inserted on the upper jaw is, as Raia shows,

the first, while that upon the hyoid is the second dorsal con-

strictor. Just so, upon the ventral side the muscle attached

to the lower jaw should be designated Csv7, that upon the

hyoid, Csv2. With this exception my account of the ventral

constrictors agrees well with that of Vetter.

On removing the skin and dissecting away the large amount

of connective tissue upon the ventral side of the body (Fig. 1),

we find immediately in front of the pectoral girdle, a pair of

muscles, the coraco-arcuales communes (Cac) which, running

forward, soon disappear under large sheets of muscle (Csv 7, ?

898 THE AMERICAN NATURALIST. [VoL. XXXIX.

which have their origin from a median line of aponeurosis and

run obliquely forward and laterally to the cartilage of the lower

jaw. This median aponeurosis starts at the level of the first

gill slit, about half an inch in front of the pectoral girdle, and

Fic. 4.— Ventral view of Acanthias showing the ventral longitudinal muscles. The right half

a deeper dissection than the left. Cac, coraco-arcualis communis; CBr 7, coraco-branchi-

: CHy hvoid

alis ; ; Cm, coraco-mandibularis.

extends to within half an inch of the symphysis of the lower jaw.

The other ventral constrictors (Csv 2-6) are visible at either

side of the coraco-arcuales communes.

The first ventral constrictor (Fig. 5, Csv 7) arises from the

No, 468.] MUSCLES OF ACANTHIAS AND RAIA. 899

median aponeurosis in common with, but ventral to, the second

(Csv2). Its fibers run obliquely forward and are inserted by

means of small tendinous portions upon the ventral edge of the

lower jaw. A few of the more posterior fibers (Csv 7a) are

Fic. 5.— A deeper dissection of Acanthias. On the right, Csz 7 has been turned back to show

the whole of Csv 2. Cac, coraco-arcualis communis; CHy, coraco-hyoideus ; Cm, cor-

aco-mandibularis; Csv 7-2, constrictores superiores ventrales; Csv ra, constrictor supe-

rioris ventralis, anterior fibers; /»zör, interbranchiales.

inserted upon the adductor of the lower jaw instead of upon the

Meckelian cartilage, and here the fibers of CsvI and Csv2

become fused so that at this point there is no sharply defined

900 THE AMERICAN NATURALIST. | [Vor. XXXIX.

margin to the first constrictor. In front the fibers of this

muscle are not separated by a median aponeurosis, but run from

one half of the jaw to the other.

Like the second dorsal, the second ventral constrictor (Fig. 5,

Csv 2) is much the largest of the series. It does not extend as

far forward as Csv 7, but, on the other hand, it extends back to

the first gill cleft. About half of its fibers arise from the me-

dian aponeurosis, run parallel with those of the first ventral con-

strictor, and are inserted on the ventral edge of the ceratohyal

cartilage. The posterior fibers, on the other hand, have their

origin in the aponeurosis separating the second and third ventral

constrictors, and, as they become too posterior to find attach-

ment to the lower jaw or to the ceratohyal, they are inserted

upon the fibrous bridge mentioned in connection with the sec-

ond dorsal constrictor (p. 895), while still farther back the fibers

run over into those of the first dorsal constrictor, passing in

front of the first gill slit and running parallel to its margin.

The remaining ventral constrictors (Csv 3-Csv 6) are closely

similar to each other, the only difference being in the points of

origin. Excepting 3 and 6, the origin is either in the aponeu-

rosis between each and the next succeeding muscle, or, in the

case of the median fibers, from the fascia between the gill cavi-

ties and the common coracoid muscles. The most medial fibers

of the second muscle take their origin, like those of Csv 2, in the

median line ventral to the common coracoids, while the sixth has

its origin in the pectoral girdle and in the fascia covering the

ventral fin-muscles. The fibers of all of these muscles are

either inserted in the aponeurosis in front, or are continued

dorsally and laterally over into the dorsal constrictors.

The function of the constrictors is to compress the pharyngeal

chamber, eject the water, and close the gill slits. The first dor-

sal constrictor may assist in raising the upper jaw, and the sec-

ond may raise the hyoid arch, while the first and second ventral

constrictors lower the under jaw and the hyoid respectively, thus

assisting in the opening of the mouth.

No. 468] MUSCLES OF ACANTHIAS AND RAIA. gol

Rata.

In removing the skin from the skate, there is less connective

tissue than in Acanthias, the constrictors are not so conspicuous,

and more muscles occur, as for instance those which control the

rostrum. The muscles, too, have been altered in relative size

and position in accordance with the modification of form in this

extreme type, but the same general relations are easily followed.

The constrictors have increased in number to seven, and,

associated with the extreme flattening of the branchial region,

the dorsal and ventral constrictors are not continuous as in

Acanthias, but are distinct, being separated at the lateral part

of the branchial region by what Tiesing has called the horizon-

tal tendon. This tendon starts from the lateral end of the hyo-

mandibular cartilage, and running along the anterior surface of

the gill region, connects with the propterygium and continues

back in the lateral branchial region, affording insertion to both

dorsal and ventral constrictors. Since the gill slits lie wholly

upon the ventral surface, the ventral constrictors in turn have

divided into median and lateral portions, the line of division

occurring at the median ends of the gill clefts (Fig. 6).

Dorsal Constrictors.— The first dorsal constrictor (Fig. 6,

Csd I) takes its origin from the lateral labyrinth region of the

skull, ventral and posterior to the postorbital process, and is

continuous posteriorly with the levator maxillae superioris, these

two muscles, as in Acanthias, having a common origin. The

fibers run forward, curving laterally along the anterior margin

of the spiracle, and are inserted on the dorsal surface of the

hyomandibula, a short distance from its anterior end. A sheet

of fascia (7) to be described later, has a part of its origin from

this muscle near its insertion; in part it also arises from the

posterior margin of the spiracle.

The second dorsal constrictor (Cs4 2) is

ferentiated than in Acanthias, having developed into distinct

muscles with different functions — an anterior levator hyoman-

dibularis and a posterior portion which agrees with the other

constrictors in position and shape.

The levator hyomandibularis (Z Hm) arises from the postero-

larger and more dif-

902 THE AMERICAN NATURALIST. (VoL. XXXIX.

/ RUDI

UN,

Hil

—

— Y

SSS

>>-

———

—

N NS

AN N

TEE

Fi. 6.— Dorsal view of Raia, more deeply dissected on the left. 45 2, adductor mandibu-

laris lateralis (superficial layer, posterior); 4» 2a same, superficial layer, anterior; Csd

tores su rsales; F 7-4, fascie; WM, hyomandibula; ZH m, levator

hyomandibularis ; Zs 5; levatores labialis superioris Li, lev: lz inferioris

Lms, levator maxillz superioris ; Zr, lev. tri t ius.

No. 468.] MUSCLES OF ACANTHIAS AND RATA. 903

lateral part of the labyrinth region of the cranium. Its fibers

run obliquely forward and outward, forming the posterior wall

of the spiracle, while the large lateralis nerve penetrates the

middle of the muscle in order to reach the region of the fin.

The muscle is inserted upon the hyomandibula, the line of

insertion beginning behind that of the first dorsal constrictor

and extending the length of the rest of the cartilage. This

muscle has become differentiated from the rest of the con-

strictor system and is only used to raise the hyomandibula.

The other more lateral and posterior portion of the second

dorsal constrictor (Csd 2) is associated with the others of the

series. Its fibers are entirely distinct from those of the levator

hyomandibularis and arise from the tendon separating the second ;

and third constrictors. This tendon is not so extensive as the

succeeding and does not extend laterally to the horizontal tendon

which is correspondingly interrupted opposite this point.

The remaining dorsal constrictors (Csd 3-7) are practically

alike. Each arises from the tendon between itself and the next

following muscle and is inserted on the tendon in front. The

seventh forms an exception in that it is smaller than the others,

and its fibers are not parallel to the main axis of the body, but

converge to the point of origin upon the shoulder girdle. The

intermuscular tendons incline more and more from the trans-

verse direction as we go farther back, and, as the muscles

extend to the horizontal tendon, they bend downward at the

lateral margin in order to reach it. A few of the fibers of

(Csd 3) are inserted in a strong tendon (F 3) which extends for-

ward from the intermuscular tendon between constrictors 2 and

3, ventral to all the adductors of the jaws, to be inserted on the

skull and surrounding tissue lateral to the nostrils.

The ventral constrictors (Fig. 3, Csv) are likewise seven in

number. The first, instead of forming a broad sheet as in

Acanthias, is divided into two portions, an anterior part, which

extends from one mandibular half to the other just behind the

symphysis, and a posterior portion. The anterior portion is not

constantly present ; I failed to find it in one specimen.

The posterior part of the first ventral constrictor is a flat fan-

shaped muscle which arises in connection with the depressor

904 THE AMERICAN NATURALIST. [Vor. XXXIX.

rostri (to be described later) in the fascia covering the coraco-

arcualis communis, and is inserted upon the mandible at about

the center of its posterior edge. This part of this ventral con-

strictor thus forms a distinct depressor mandibuli (Dm). Only

the anterior edge of the origin of this muscle can be seen until

the depressor rostri (Fig. 15, Dr) is removed, but the method of

description necessitates its mention here.

The second ventral constrictor is likewise much modified from

the condition in Acanthias, being divided into an anterior depres-

sor hyomandibularis (D//m) and a posterior second ventral con-

strictor proper (Csv 2).

The depressor hyomandibularis has its origin in the fascia

overlying (ventral to) the coraco-hyoideus, the fascia connecting

the depressors of the two sides dorsal to the coraco-mandibu-

laris. The general course of the muscle is transverse to the

longitudinal axis of the body. The fibers converge from a

broad flat origin to a cylindrical muscle which then runs dor-

sally and becomes inserted upon the posterior end of the ventral

edge of the hyomandibula and upon the horizontal tendon. The

posterior portion of the second ventral constrictor has its origin

in part in the tendon (less developed than the others) separating

it from the third ventral constrictor, while the more lateral fibers

are continuous with those of the third constrictor, there being

no aponeurosis between them. The fibers run forward, con-

verging from either side toward their insertion on the horizontal

tendon. ;

Each of the remaining ventral constrictors (Csv 3—Csv 7) is

composed of two parts, a large median and a smaller lateral por-

tion, the muscle becoming smaller toward the lower limits of

the gill region. The tendons separating the constrictors (the

first two are united medially) run obliquely outward and back-

ward to the median ends of the gill slits and then turn abruptly

and pass to the middle of the gill slit behind, so that this por-

tion of the tendon serves to separate the median from the lateral

parts of the muscle.

The origin of the median portion of the seventh ventral con-

strictor is from the fascia covering the ventral edge of the

coraco-branchialis. The other muscles arise from the tendon

No. 468.) MUSCLES OF ACANTHIAS AND RAIA. 905

behind. In all, the fibers are inserted upon the tendon in front,

and their courses are somewhat oblique near the median side, and

nearly at right angles to the body axis at their outer margins.

The lateral portions of the constrictors arise from the ten-

dons between them and the median muscle, and the fibers run

laterally to some small cartilages (not always present) and then

turn dorsally to be inserted on the horizontal tendon.

Interbranchiales.

Acanthtas.

It is a question whether these should be included among the

superficial circular muscles or not, since they are in no sense

SE)

IS.

ZEE

branchiales. Csd 3,

Fic. 7 — Lateral view of Acanthias to show the inter’ 7 3, const " uperioris

Lin 3; Csv 3, constrictor superioris ventralis 3 ; /ntör, interbranchialis; 7 io) napa

superficial, nor circular in the same sense that the other muscles

are, and they lie in a different plane. However, they are closely

allied with the constrictors in function, assisting in the general

contraction and expansion of the gill basket, and since compari-

sons with Vetter are made easier, they are retained here. |

906 THE AMERICAN NATURALIST. | [Vor. XXXIX.

These muscles (Figs. 5, 7, 8, 11, /ntör) are fewer in number

and lie between the demibranchs of the four complete gills.

Each is extremely thin and consists of a sheet of fibers, anterior

to the cartilaginous gill rays, and extending between the gills

Fic. 8.— Lateral view of. Acanthias, showing the interb hiales (u£br). T, trapezius.

from top to bottom of the septum. A tough white fascia

extends from the dorsal longitudinal muscles to the extra-

branchial cartilages, holding the latter in place below the apo-

neurosis between the dorsal constrictors, and connecting them

with the interarcual muscles to be described later. The most

dorsal of the interbranchial muscle fibers arise from the fascia

just described, while the rest have their origin in the aponeurosis

between the dorsal constrictors. The more median of the fibers

curve outward and downward toward the median line, to become

inserted on the anterior margin of the epibranchial cartilage

(Fig. 7). The more lateral fibers are larger and follow a broad

curve from the dorsal to the ventral side of the gill septum, and

thus pass into the ventral fibers about to be described, just as

the dorsal and ventral constrictors merge in part into each other.

The ventral fibers arise from the extrabranchials as well as

No. 468.] MUSCLES OF ACANTHIAS AND RAIA. 907

from the tendinous fasciz connecting these cartilages, while the

fibers on the median side arise from the fascia between the longi-

tudinal muscles (Fig. 5 shows an instance of origin at the end

of the common coraco-arcualis). This point is of some impor-

tance in the interpretation of the condition in Raia. The fibers

near the middle line are inserted upon the anterior surface of

the cerato-branchial cartilage, while the lateral fibers are contin-

uous with those of the dorsal side as noted above. Often the

muscle fibers stop at a gill ray, the tissue becoming aponeurotic,

and then the muscle fibers continue on the other side.

These interbranchial muscles draw the gill radii together and

thus aid in the contraction of the gill basket. In the case of

the hyoid arch, the second dorsal and ventral constrictors replace

the interbranchialis, since here the gill radii lie immediately

beneath the surface (constrictor) muscles.

Rata.

The interbranchiales of Raia are much like those of Acanthias

in position and number, the muscle of the first arch being

replaced by the posterior part of Csv2 and Csd2. Owing to the

shape of the branchial region they do not form a continuous arc

but are divided into a dorsal and a ventral portion, so that the

line of division coincides with the angle separating the halves of

each branchial arch. The muscle fibers of the dorsal portion

arise from the aponeuroses between the dorsal constrictors, and

run ventrally (Fig. 12) until they become inserted upon the

dorsal surface of the epibranchial cartilages or upon the ray

which runs out from the angle to the horizontal tendon. The

ventral fibers take their origin from the tendons between the

ventral constrictors and run dorsally to their insertion upon the

ventral surfaces of the cerato-branchials or upon the horizontal

ray just referred to. The fibers never become continuous, as in

Acanthias, from dorsal to ventral surfaces. A few bundles of the

most median fibers of the ventral portion are overdeveloped, and

have extended so as to take their origin from fascize covering the

coraco-mandibularis muscle (Fig. 3, /nzor). A similar condition

was noted above for Acanthias but these fibers were not as

908 THE AMERICAN NATURALIST. | (Vor. XXXIX.

prominent there as here. Tiesing, basing his opinion on the

work of Vetter upon Heptanchus, has regarded these fibers as

a deeper layer of the constrictor but Acanthias shows this not

to be tenable. There is no resemblance to a constrictor. In

the case of the fourth arch the corresponding fibers extend into

Fic. 9.— Dorsal view of gill arches of Acanthias to show the interarcuales. £, groove ;

Intarc 1-4, interarcuales ; Ss, subspinalis.

tough tendons connected with the coraco-arcualis communis mus-.

cle (Fig. 3). On the dorsal side there is but one instance of

this extension of the interbranchials (Fig. 6, at the inner poste-

rior angle of Csd6). A few fibers take their origin from the

sides of the first vertebra. This could not be considered a

constrictor.

Levator Maxillae Superioris.

Acanthias.

This muscle (Figs. 2, 11, 14, Lms), already mentioned in con-

nection with the first dorsal constrictor, árises in common with

it from the lateral surface of the cranium just posterior to the

No. 468.] MUSCLES OF ACANTHIAS AND RAIA. 909

postorbital process. It is larger than the first dorsal constrictor

and fills the: entire bay back of the postorbital process. The

fibers extend anteriorly and ventrally to their insertion on the

dorsal margin of the palatal process of the upper jaw, just ante-

rior to the attachment of the first dorsal constrictor. In fact

the only distinction that can be drawn is that in the levator the

fibers go directly to the jaw while those of the first dorsal con-

strictor curve around the anterior margin of the spiracle.

Raia.

In the skate the levator of the upper jaw (Figs. 3, 6) is com-

posed of a thick dorsal and a thinner ventral layer, the two

united at their point of insertion. The thicker layer (Lms)

arises from the side of the skull, just ventral to the postorbital

process, and its fibers run almost straight forward, then dorsal

and backward in front of the oral cavity to their insertion on

the upper jaw. The thinner and more ventral layer (Zu) arises

‘just below and behind the facial foramen whence its fibers run

forward, laterally, and backward to unite with the dorsal layer.

This course involves a strong lateral bend from which a strip of

fascia extends to the hyomandibular cartilage (Fig. 6). Some of

the more ventral fibers are inserted in the membranous wall of

the roof of the mouth.

Tiesing maintains that the levator maxillae superioris is only

a deeper part of the first dorsal constrictor,— a view rendered

very probable from the relations in Acanthias in which the con-

ditions are the more primitive. It is very similar to a constric-

tor in origin and function, although differing widely.in form.

Trapezius.

Acanthias.

The trapezius (Figs. 2, 7, 8, H, Tr) has its origin in fascia

covering the sides of the dorsal longitudinal muscles. Its fibers

arise from a straight line extending from the posterior end of the

cranium to the dorsal part of the shoulder girdle, although the

910 THE AMERICAN NATURALIST. (VoL. XXXIX.

muscle extends through only the posterior three fourths of this.

The fibers, which become thinner posteriorly, run obliquely down-

ward and backward, the majority being inserted on the anterior

edge of the pectoral girdle, while the more anterior fibers turn

directly downward and are inserted on the dorsal edge of the

last branchial arch. At intervals tendinous strands of the dorsal

FiG. 10.— Ventral vi f Acanthias showi

g th branchiales. CBr, coraco-branchiales ;

Csd 2-6, constrictores superiores dorsales; Znźór, interbranchialis.

constrictors (Fig. 11, Csd) as already described, pass through this

muscle. The function of the trapezius is to raise the girdle and

draw it forward.

Rata.

A trapezius has not been described in the skates but there

occurs here a muscle (Fig. 6, 77) which in its attachments and

No. 468.] MUSCLES OF ACANTHIAS AND RATA. 9II

the direction of its fibers somewhat resembles it although it does

not in all respects fulfill the conditions found in Acanthias.

There are here three parts to the muscle: a small median por-

tion and two more lateral in position.

The median, the smallest, arises from the side of the first

vertebra and its fibers run obliquely backwards to be inserted on

the anterior edge and ventral surface of the suprascapula. The

most lateral portion arises near the first and its fibers run ob-

liquely backward and outward to the insertion upon the upper

surface of the last visceral arch and on the anterior edge of the

girdle far down towards the ventral edge. The remaining por-

tion arises just ventral to the part just described and its fibers

are attached to the scapular portion of the pectoral girdle. (In

Raia radiata the median portion is greatly reduced and its origin

is from the lateral process of the vertebra, just back of that of

the next division.)

The two lateral portions of the muscle in Raia are apparently

partly antagonistic, that first described elevating, the other de-

pressing the girdle to a certain extent.

Levator Labialıs Superioris.

Acanthias.

Although Vetter classifies this muscle among the adductors

he says (74, p. 448): “Er erscheint als seriales Homologon

des M. levator max. sup. und aller der andern Theile des gros-

sen Constrictors, welche vom Schadel oder von der epaxionischen

Muskulatur zu der Visceralbogen gehen, und ist sonach passen-

den als M. levator labii sup. zu bezeichen." For this reason I

have included it among the other similar constrictors. This

muscle (Fig. 1, Z/s) has its origin from the ventral surface of

the cranium, in front of the basal process and to one side of the

middle line. The fibers run outwards and backwards, describ-

ing an arc to the angles of the mouth where they converge to a

straight fibrous tendon which passes dorsal to the labial carti-

lages, crosses the angle of the mouth at right angles, and is

inserted among the fibers of the adductor mandibularis.

912 THE AMERICAN NATURALIST. [Vor. XXXIX.

Rata.

The levator labialis superior in the skate has been differen-

tiated into five parts (Figs. 3, 6, Zs 7-5). Of these the first

(Lis 7) most nearly resembles the single muscle of Acanthias.

It is small, cylindrical, and arises from the ventral surface of

the cranium near the orbit and just behind the base of the eth-

moid process. It runs laterally and then backward to the angle

of the mouth, which it passes, to become inserted in the fascia

Fic. 11.—

Lateral view of Acanthias showing een and trapezius, Csd 1-6, con-

res ist es dorsales; Csz za, or superioris ventralis, anterior fibers;

Cre strictor superior is ventralis 2; /ntbr 1-4,

interbranchiales ; Las, levator maxilla:

sepeioris; Tr, trapez

constri

between the

it separates.

The second division (Fig. 6,

labial muscles.

adductores mandibularis medialis and lateralis which

Lis 2) is much the largest of the

It arises from the dorsal surface of the most

lateral part of the ethmoid region in front of the antorbital proc-

ess. The origin is small and of rather soft fibrous material.

After passing dorsally of the large mass of the adductor man-

No. 468.) MUSCLES OF. ACANTHIAS AND RAIA. 913

dibularis lateralis 22, it widens into a large muscle which dis-

appears under the adductor mandibularis lateralis 2 to become

inserted on the mandibular cartilage while a portion of its fibers

become confused with the posterior portion of Ami 2 (Fig. 3).

The third division (Fig. 6, Z/s 3) is thé smallest of the sys-

tem: a short thick muscle running from the postero-lateral edge

of the dorsal surface of the nasal capsule, laterally, to the poste-

rior dorsal angle of the antorbital process, the fibers converging

towards the insertion.

The fourth division (Fig. 3, Lis 4) is broad, thin, and flat,

and its origin is continuous with and ventral to that of the third

division. It lies upon the adductor mandibularis lateralis and

covers a portion of‘ it ventrally. The mandibularis branch of

the fifth nerve runs between the two. Its general course is

posterior and the fibers which are not inserted in the fascia

covering the adductor mandibularis lateralis converge to a

strong tendon, which makes its way through that muscle, to

their insertion on the ventral surface of the mandible.

The fifth division (Fig. 6, Z/s 5), though included by Tiesing

among the muscles, is but a group of strong tendinous fibers

having its origin just posterior to that of the second division

and its insertion on the strong fascia enveloping that muscle.

Muscular tissue is lacking in it, and it is scarcely more than à

second origin of that muscle.

Levator Rostri.

This muscle (Fig. 6, Zr), together with the next, would be

treated first among the superficial muscles were we describing

Raia alone, but since it is lacking in Acanthias it has been left

until now. Upon removing the skin from the dorsal surface,

the levator rostri is the first seen and most superficial of the

muscles. It takes its origin from the lateral edge of the lateral

process of the first vertebra which projects above the surround-

ing muscles, and from the tendinous fascia covering the muscles

in this region. The fibers run obliquely forward, converging to

the region where they cross the levator maxille superioris and

the first dorsal constrictor where they pass into a strong cylin-

914 THE AMERICAN NATURALIST. [VoL XXXIX.

drical tendon. This tendon continues forward, passing outside

the spiracle and the eye and over the various jaw muscles and

the antorbital cartilage, into the fascia of the rostral region

where it is inserted in the strong membranous tissue stretching

between the rostrum and the propterygium.

Depressor Rostri.

The depressor rostri (Fig. 15, Dr), the antagonist of the last,

is a broad, flat, thin muscle arising from the fascia covering the

coraco-mandibularis and from the fibers of the coraco-arcualis

communis. The muscle extends forward and outward in the

direction of the adductor muscles where some of the lateral

fibers are inserted in the white fascia covering these muscles,!

while the majority are collected into a strong tendon which

extends forward, lateral to the nasal capsule and ventral to the

antorbital process, then coming towards the median line is in-

serted in the membranous tissue between the tip of the rostral

cartilage and the propterygium.

INTERARCUALES.

Acanthias.

The interarcuales (Fig. 9) are divided into two systems of

muscles: one more medial, the other more lateral in position,

each consisting of four muscles, similar in function, the first of

the medial system being the subspinalis of Vetter ('74, p. 444).

Medial System.— The most anterior of the medial interarcu-

ales has been treated as a distinct muscle, the subspinalis, by

Vetter but as it agrees closely with the others in function and

differs only in its origin from the rest, it is here regarded as

but one of the set. Its origin is from the fascia on the under

side of the dorsal longitudinal muscles, from the vertebrze near

the cranium, and from the under side of the cranium itself just

in front of the foramen magnum. From this broad origin it

1 [n Raia radiata most of the fibers have this insertion,

while a small proportion

are continued into the rostral depressor tendon.

No. 468] MUSCLES OF ACANTHIAS AND RAIA. 915

tapers to a tendon which is inserted upon the dorsal posterior

end of the first pharyngo-branchial. It draws the first pha-

ryngo-branchial forward in the same way that the succeeding

muscles draw the pharyngo-branchials upon which they are

inserted.

The second, third, and fourth medial interarcuales arise from

the posterior surface of the first, second, and third pharyngo-

branchials respectively, a little in front of the middle of each

and are inserted upon the dorsal surface of the second, third,

and fourth pharyngo-branchials. The point of attachment is

at about the middle of the cartilage except in the case of the

second where the attachment is behind the middle. These

muscles have a larger surface of insertion than of origin and

decrease in size from in front backwards.

Lateral System.— A description of the first of the four will

answer for the first three muscles of this system. The first

lateral interarcuale has a double origin. The majority of the

fibers arise from the posterior edge of the anterior end of the

first pharyngo-branchial and a few from the anterior end of the

second pharyngo-branchial just in front of the groove (g) for

the passage of the blood vessel. The fibers are inserted on the

dorsal surface of the epibranchial along a line which is a con-

tinuation of the line of insertion of the interbranchial muscle.

Some of the fibers are inserted so far laterad as to be in front of

the most dorsal gill rays, so that the muscle appears to be

almost a portion of the interbranchial which has been forced

deeper for its origin. The last lateral interarcuale differs from

the rest only in its origin. Since the fourth and fifth pharyngo-

branchials are fused the origin is not divided.

Rata.

The interarcuales are much reduced in the skate; indeed

only the lateral system persists while the medial system is rep-

resented by non-muscular membranes. connecting the pharyngo-

branchial cartilages in the same way. Each of the muscles of

the lateral system arises from the posterior edge of the anterior

end of the pharyngo-branchial and is inserted upon the medial

end of the epibranchial of the same arch.

916 THE AMERICAN NATURALIST. | (VoL. XXXIX.

It may be a question whether the interbranchiales, the inter-

arcuales, and the adductores (next to be described) do not form

a system of deep as opposed to the superficial constrictors.

Each contributes toward the constriction of the whole branchial

region, and, with the exception of the largest mandibular adduc-

tor, each lies beneath the more superficial system.

ADDUCTORES.

The adductor muscles draw together the ventral portions of

each visceral arch. In the case of the mandibular arch they

close the mouth, while in the gill arches they occur at the lateral

hinge and approximate the ceratobranchial and epibranchial por-

FIG. 12, — Anterior side of interbranchial muscle of Raia. Aab, adductor arcus branchialis ;

Intr, interbranchiales.

tions of each. The adductors of the first (mandibular) arch are

enormously developed in correlation with the use of these parts,

while those of the gill arches are very small. In Acanthias the

adductors are much simpler than in Raia.

Adductores Mandibulares.

Acanthias.

very strong tendinous envelope. Its fibers arise from the quad-

rate region of the upper jaw, and are attached to the entire

lateral surface as well as to the medial surface of the muscle

process on its dorsal margin. The course of the fibers is down-

The mandibular adductor (Figs. 1, 2, 13, 14, Am) has a

No. 468.) MUSCLES OF ACANTHIAS AND RAIA. 917

ward and backward to the lower jaw where they are attached to

the entire width of Meckel's cartilage. The details of the

course of the fibers are rather difficult to express. On the

lower jaw (Fig. 1) they extend nearer to the middle line than

on the upper, and this portion (r) instead of coming from the

fascia which separates it from the rest, comes from the posterior

part of the upper jaw. A strong tendon is attached to this part

which runs forward into the levator labialis superioris muscle.

Other fibers are specialized in function. A broad thin sheet

of fibers is extended on the upper half of the adductor and has

its true origin from the under surface of the postorbital process,

while a strong mass of tendinous material at the angle of the eye

(Fig. 13, y) gives origin to some of the fibers. A few fibers of

the first ventral constrictor, which have already been referred

to as Csv Za, are attached to the outer surface of the adductor.

Rata.

In the skate the adductor muscles are more complicated.

They cover and surround the lateral ends of the jaws and are

divided into distinct and easily separated layers. Following

Tiesing, they may be grouped into a small medial, and a larger

lateral portion, the latter in turn divisible into deeper and super-

ficial layers.

Adductor Mandibularis Medialis— This, the smallest of the

adductors (Figs. 3, 6, Amm) arises from the anterior edge of

the upper jaw. Its fibers run back across the angle of the

mouth and then medially to become inserted near the anterior

(occludent) margin of the lower jaw not far from the symphysis.

Its origin is in common with the deeper layer of the lateral

adductor and the two separate where the levator labialis superi-

oris passes to become attached to the fascia between them.

The adductor mandibularis lateralis is subdivided into a deep

layer (Figs. 3, 6, Am /,) and a more superficial portion ( Ami 2

and Aml 2a). The deep layer is largely covered by the super-

ficial. The majority of its fibers arise from the anterior edge of

the upper jaw as well as from the entire outer surface of the

muscle process, and they find their insertion upon the outer sur-

face of the lower jaw about opposite the point of origin.

918 : THE AMERICAN NATURALIST. (Voi: XXXIX.

The second division of the levator labialis superior, in its

course to its insertion on the ventral surface of the lower jaw,

crowds into the superficial layer of the lateral mandibular adduc-

tor, separating it in part into anterior and posterior portions.

The anterior of these divisions (Am/ 2a) arises in part from the

dorsal surface of the lower jaw, directly opposite to its point of

attachment to the deeper layer, and in part from the ventral

Fic. 13.— Lateral view of adductor mandibularis of Acanthias. Am, adductor mandibularis ;

Csv ra, constrictor superioris ventralis, anterior fibers; y, tendinous mass back of eye.

surface by means of a very strong fibrous tendon. It runs for-

ward, passing dorsally to the upper jaw and immediately broad-

ens out into a large mass of fibers which curve ventrally and run

backward, covering the deeper layer of the adductor and finally

becomes inserted upon an aponeurosis surrounding the deeper

layer. From this aponeurosis the fibers start again and continue

backward, completely encasing the ends of both jaws, to the

insertion directly and by means of tendons upon the lower jaw.

Adductores Arcus Branchialis.

The hyomandibular and hyoid cartilages are bound together

at their articulation by strong ligaments, but no adductors are

present connecting the two. In the branchial arches proper

such muscles occur.

No. 468] MUSCLES OF ACANTHIAS AND RAIA. 919

Acanthitas.

A few short adductor muscle fibers extend between the cerato-

and epibranchial cartilages of each branchial arch. They have

their origin in small grooves on the inner surface of the epi-

branchials and are inserted in similar grooves on the inner

(dorsal) surfaces of the ceratobranchials. Their function is to

flatten the branchial region.

Rata.

In the skates (Fig. 12, Aad) the adductors of the branchial

arches closely resemble those of Acanthias. They arise from

NINN

SR S Qae GY / z——

RUN SS >= 7 ZEN

Cor

Fıc. 14.— Side view of Acanthias after removal of the skin. Am, adductor mandibularis ;

Cac, coraco-arcualis communis; Csd 1-6, constrictores superiores dorsales ; Csv 1-6, con-

strictores superiores ventrales ; Csv ra, constrictor superioris ventralis, anterior fibers ;

Gs, gill slits; A, hinge of jaws; L4s, levator labialis superioris ; Lys, levator maxillz sup-

erioris ; 77, trapezius.

and are inserted in similar grooves in epi- and ceratobranchial

cartilages, while a few of the fibers extend some distance along

the ceratobranchial before finding their insertion.

920 THE AMERICAN NATURALIST. |. [Vor. XXXIX.

VENTRAL LONGITUDINAL MUSCLES.

The location and character of these muscles is apparent from

this name. In Acanthias they are usually thick and solid, while,

correlated with the depressed body, they are flat and thin in

Raia.

Coraco-mandibularis.

Acanthias.

In the dogfish the coraco-mandibularis is an azygos muscle

lying in the median line of the body, and is exposed (Fig. 5, Cmm)

by removing the ventral constrictors. It is the most superficial

of the ventral longitudinal muscles. It arises from the fascia

between the coraco-arcuales communes and its fibers rapidly

diverge near the origin, where the muscle is nearly circular in

section, to form a flattened band which is inserted on the poste-

rior edge of the lower jaw on either side of the symphysis.

Raia.

In the skate the coraco-mandibularis (Figs. 3, 15, Cm) also lies

in the median line but is not covered by the ventral constrictors,

since these are here more lateral in position, with the exception

of a few fibers (Fig. 3, Csv 7) already described. In origin and

insertion there is a close agreement with Acanthias, but the mus-

cle is thinner and flatter than in that form. With the exception

of the depressor rostri and the depressor mandibuli, whose ori-

gins overlap its margin, it is the most superficial of all the ven-

tral muscles.

Coraco-hyoideus.

De Acanthias.

The coraco-hyoideus muscles (Fig. 4, Chy) are exposed by

removing the coraco-mandibularis, which lies close to the me-

dian line. They are the largest of the ventral longitudinals.

No. 468) MUSCLES OF ACANTHIAS AND RATA. 92I

The origin of each is very long, extending along the fibrous

aponeurosis between it and the coraco-branchialis and the cor-

aco-arcualis communis, from beneath the origin of the coraco-

mandibularis halfway to its insertion on the ventral side of

the hyoid copula just behind the lower jaw. The muscle is as

thick as broad and only diminishes slightly in size in front.

Rata.

In the skate the coraco-hyoideus muscles (Fig. 3, Chy) are

reduced, flat, and thin. Each arises from the fascia covering

the large coraco-hyomandibularis, near the origin of the second

interbranchial muscle and is inserted upon the ventral surface

of the hypohyal cartilage. It lies deeper than the depressor ros-

tri, the depressor mandibularis, and the depressor hyomandib-

ularis, and directly upon the coraco-hyomandibularis.

Coraco-branchialis.

Acanthtas.

The coraco-branchialis (Figs. 4, 10, Cér) is the deepest and

most dorsal of the ventral longitudinal muscles and forms the

lateral wall of the pericardial cavity. It is composed of five

parts, of which the last four have a common origin. The first

division (Cér 7) arises from an aponeurosis directly beneath the

coraco-hyoideus, and running dorsally becomes inserted on the

dorsal surface of the medial end of the hyal cartilage. It is

much shorter than the ceratohyoid and is contracted near its

insertion. : i

The four remaining coraco-branchials (Fig. 10, Cbr 2-4) arise

from a strong membrane running from the girdle to the origin of

the ceratohyoid. As the fibers pass forward and laterally they

divide into separate portions, the anterior of which becomes

inserted on the branchial arches, while the last, which is much

the largest, is inserted upon the fifth arch and upon the lateral

half of the copula. Blood vessels pass through the arches

between the divisions of the muscle.

922 THE AMERICAN NATURALIST. [Vor. XXXIX.

Fic. 15.— Raia, ventral view, after removal of the skin ; right half more deeply dissected. Cac,

as. y Moses | libulari Cm,

= hi

coraco-arcualis communis; CB.

7, coraco H , y > ’

coraco-mandibularis ; Csv 7, constrictor superioris ventralis ı; DÆ, depressor hyoman-

dibularis; Dr, depressor rostri; /nfór 7-3, interbranchiales.

No. 468.] MUSCLES OF ACANTHIAS AND RAIA. 923

Rata.

In Raia this muscle (Fig. 15, Có») which forms the lateral

wallof the pericardial cavity, arises from the pectoral girdle.

Farther forward the muscle expands and the tendon gives place

to muscle fibers which are inserted on the anterior process of

the basibranchial and the membranous floor of the mouth. The

other fibers run dorsally and become attached to the ends of the

cerato- and hypobranchials. The divisions between these parts,

as in Acanthias, permit the passage of blood vessels, and extend

nearly back to the origin dividing the muscles into superimposed

layers.

Coraco-arcuales communes.

Acanthias.

The paired coraco-arcuales communes muscles (Figs. 4, 5,

Cac) lie immediately beneath the skin and arise from the cora-

coid region of the girdle. The fibers run inward and forward,

and the medial fibers become inserted in the strong membrane

which forms the floor of the pericardium, while the lateral parts

are inserted upon the fascia dorsal to the origin of the cerato-

hyal. Each muscle is crossed by four myosepta, which makes it

resemble somewhat the ventral body muscles behind the girdle.

Raia.

In the skate (Figs. 3, 15, Cac) this muscle closely resembles

that in Acanthias in origin, direction, and insertion.

Coraco-hyomandibularis.

This wide, comparatively thick, and long muscle occurs only

in Raia (Figs. 3, 15, Chm) of the forms studied, where it is the

largest and most important of the ventral longitudinal muscles.

It arises from a fascia in the middle line, and runs forward nearly

to the division of the ventral aorta. The muscle runs obliquely

924 THE AMERICAN NATURALIST. | (Vor. XXXIX.

forward and outward, passes the first hypobranchial on the dor-

sal side, and converges to a small flat tendon on the anterior ven-

tral surface of the hyomandibula.

SUMMARY.

In the foregoing, all of the muscles of the head and the bran-

chial region, with the exception of the eye muscles, have been

considered. The two forms studied agree very closely when

their difference in shape is considered.

In the skate, as might be expected from its extreme modi-

fication, a few muscles are developed which are not found in

the dogfish. These are the levator and depressor of the ros-

trum, and the cerato-hyomandibularis which, from its position,

seems adapted to the protrusion of the jaws.

The muscles of the skate referred to by Tiessing as “ Csvp

3-5,” are here interpreted as fibers of the interbranchials which

have acquired an extreme development.

The muscles in Acanthias, marked Csv 2 and Csß 2 by Vetter,

are here regarded as the first and second ventral constrictors

respectively.

The deeper ventral need muscles of Raia are described

for the first time.

LITERATURE.

DRUNER; L.

:03. Ueber die Musculatur des Visceralskelettes der Urodelen. Azat.

Anz., vol. 23, pp. 545-571, 16 figs.

TIESING, B.

'95. Ein Beitrag zur Kenntnis der Augen-, Kiefer-, und Kiemenmuskula-

tur der Haie und Rochen. Jen. Zeitschr. f. Naturw., vol. 30, PP-

75-126, pls. 5-7.

VETTER, B.

"74. Untersuchungen zur vergleichenden Anatomie der Kiemen- und

Kiefermusculatur der Fische. Jen. Zeitschr. f. Naturw., vol. 8,

Pp. 405-458.

OCCURRENCE OF ECHINOSTOMUM SPINULOSUM

RUD.

N. C. GILBERT.

IN THE intestinal coeca of an adult male Loon (Gavia imber)

killed near Ann Arbor, Michigan, in April, 1904, I found from

forty to fifty mature distomes, which I have identified as Echin-

ostomum spinulosum Rudolphi, a worm which I have not been

able to find hitherto reported for North America. Later, in

August of the same year, I obtained eight more specimens from

the intestine of a Bonaparte's Gull (Zarus philadelphia). In

each case the specimens were in a badly macerated condition.

There was this unimportant difference from the European

species, that my specimens averaged somewhat smaller. Their

length was about 2.37 mm., while the length for the European

species is given as from 3-10 mm. (Stossich, '92). The ana-

tomical differences are also very slight between this species and

E. pseudoechinatum Olsson, Æ. euryporum Loos, E. mordax

Loos, and Æ. pendulum Loos, and make this species very dif-

ficult to differentiate. These differences are, however, very

accurately described by Loos ('99), and although slight, seem

constant.

The body of the specimens which I obtained is elongated,

subcylindrical, widest at the acetabulum, and tapers gradually

posteriorly. Length, 2.37 mm.; width at acetabulum, 0.29 mm.

The neck is constricted, and is armed with spines, arranged in

regular rows, which extend as far as the posterior border of the

acetabulum. The anterior end is conical in shape, with an

expanded base, and is armed with twenty-two oral spines, in a

single row, and of equal size. +

The oral sucker is located at the extreme anterior end ; diam-

eter, 0.08 mm. The acetabulum is located 0.61 mm. from tHe

anterior end ; diameter 0.17 mm. The pharynx is located close

behind the oral sucker, and the intestine divides just anterior to

925

926 THE AMERICAN NATURALIST. [Vor. XXXIX.

the acetabulum into two coeca of equal length, which extend to

the posterior extremity.

The ovary is situated 0.15 mm. back of the

Ph acetabulum, in the median line, is round, and

is 0.05 mm. in diameter. The oviduct passes

posteriorly, makes two simple coils, receives

the vitelline duct, and is surrounded by the

VS shell gland. It then passes anteriorly, and

after a few turns, it opens to the exterior just

anterior to the acetabulum, and beside the

V cirrus-sac. The ova are rather large, oval,

0.09 by 0.06 mm., and from four or five to

twenty-four were counted in one individual.

The vitelline glands consist of a large num-

ber of simple follicles, and extend as far an-

I teriorly as the anterior border of the posterior

VG testis. They are scattered over the entire

region as far back as the ends of the intes-

tinal coeca, and show a distinct bilateral ar-

E . rangement. They open by two lateral ducts

into a median receptacle, just anterior to the

Fic. 1. — Echinostomum testis.

en. u voter The testes are oval and relatively large,

ide, m ae nd and located in the same antero-posterior line ;

‚ovary; v, vitelline re- length, 0.17 mm. by 0.12 mm., and 0.03 mm.

= "ors vieles ganz. Apart.

The cirrus-sac and seminal vesicle lie just

beneath the anterior margin of the acetabulum, and open to the

exterior a short distance anterior to it.

No. 468.] ECHINOSTOMUM SPINULOSUM. 927

LITERATURE.

BAIRD, W.

'55. Catalogue of the Species of Entozoa, or Intestinal Worms, con-

tained in the Collection of the British Museum. London, 132 pp.,

tab. 1-2.

CREPLIN, F.C.H.

'46. Nachtrage zu Gurlt’s Verzeichniss der Thiere bei welchen Entozoa

gefunden worden sind. Arch. f. Naturgesch., vol. 12, pt. t, pp.

129-1

DIESING, C. M.

'50. Systema Helminthum. Vindibone, 680 pp.

DIESING, C. M.

'58. Revision des Myzhelminthen, Abtheilung Trematoden. .SZ/zwzgsó.

kaiserl. Akad. Wissensch. Wien, vol. 32, pp. 307-370, pls. 1-2.

DUJARDIN, F.

"45. Histoire naturelle des helminthes. Paris, iv + 654 + 15 pp., 12 pls.

LINSTOW, O. VON.

’77. Enthelminthologica. Arch. f. Naturgesch., vol. 43, pp. 173-198,

pls. 13-14.

Loos, A.

'99. Weitere Beiträge zur Kenntniss der Trematoden-Fauna /Egyp-

tens. Zoöl. Jahrb., Abth. f. Syst., vol. 12, pp. 521—784, pls. 24-32.

Mouin, R

'58. Prospectus Helminthum que in Prodromo Faunæ Helminthologice

Venetiæ continentur. Sifzungsb. katserl. Akad. Wissensch. Wien,

vol. 30, pp. 127-158.

MOLIN, R.

'61. Prodromus Faunæ Helminthologicæ Venetiæ, adjectis Disquisitioni-

bus Anatomicis et Criticis. Denkschr. kaiserl. Akad. Wissensch.

Wien, vol. 19, pp. 189-338.

RUDOLPHI, C. A

- 08-10. Entozoorum, sive Vermium Intestinalium Historie Naturalis,

Amstelaedame. Vol. 2, 386 pp.

RUDOLPAHT, C. A.

'19. Entozoorum Ense Berlin, 811 pp., 3 pls.

STOSSICH, M.

'92. Idistumi degli uccelli. Trieste, 54 pp.

NOTES AND LITERATURE.

BOTANY.

The Journals. — Bulletin of the Torrey Botanical Club, March :—

Rydberg, ‘Studies on the Rocky Mountain Flora"; House, * Two

New Species of Convolvulus from the Western United States”;

Harper, *Phytogeographical Explorations in the Coastal Plain of

Georgia in 1903.”

Bulletin of the Torrey Botanical Club, April:—Evans, * New or

Noteworthy Hepaticz from Florida"; Eastwood, “ New Species of

Western Plants”; Maxon, “A New Botrychium from Jamaica”;

Cushman, ** Notes on the Zygospores of Certain New England Des-

mids, with Descriptions of a few New Forms.”

Bulletin of the Torrey Botanical Club, May :— Toumey, * Notes on

the Fruits of some Species of Opuntia "; Howe, ** Phycological Stud-

ies— I. New Chlorophycez from Florida and the Bahamas";

House, “Notes on New Jersey Violets"; Britton, “ Bryological

Notes — 11.”

Bulletin of the Torrey Botanical Club, June: — Evans, * Hepatice

of Puerto Rico — V. Ceratolejeunea "; Underwood, * A Summary

of Charles Wright's Explorations in Cuba " ; Kauffman, * The Genus

Cortinarius — a Preliminary Study”; Berry, “ A Ficus confused with

Proteoides."

The Fern Bulletin, April : — Eggleston, “ The Fern Flora of Ver-

mont”; Clute, “What Constitutes a Species in the Genus Isoetes " ;

Flett, “Observations on Lycopodium selago-lucidulum”; Parish,

“ Ophioglossum californicum in Central California”; Clute, “The

Round-leaved Maiden Hair ” Eaton, “Notes on Isoetes”; Taylor,

“How and where Ferns grow in Southwest Georgia.”

Journal of Mycology, March : — Morgan, “The Genus Gibellula ” ;

Arthur, “Cultures of Uredinez in 1904”; Kellerman and Ricker,

* First Supplement to * New Genera of Fungi published since the

Year 1900,’ with Citation and Original Descriptions ”; Kellerman,

* Notes from Mycological Literature — XIV."

929

930 THE AMERICAN NATURALIST. | [Vor. XXXIX.

Journalof the New York Botanical Garden, April: — Howe, “ Some

of the Coralline Seaweeds in the Museum”; Nash, “The Crested

Orchid.”

Journal of the New York Botanical Garden, May : — Britton, “ Ex-

plorations in the Bahamas"; Cowell, *Report on Explorations in

Panama."

Journal of the New York Botanical Garden, June: — MacDougal,

“ Botanical Explorations in Arizona, Sonora, California, and Baja

California."

Journal of the New York Botanical Garden, July : — Murrill, “A

Trip to Cuba"; Hollick, * The Preservation of Plants by Geologic

Processes."

The Ohio Naturalist, April: — Claassen, “Key to the Liverworts

recognized in the Sixth Edition of Gray's * Manual of Botany '";

Smith, * Key to the Ohio Elms in the Winter Condition ”. Gleason,

“Notes from the Ohio State Herbarium — III” ; Riddle, * Develop-

ment of the Embryo-sac and Embryo of Staphylia trifoliata.”

The Ohio Naturalist, May: — Schaffner, “The Nature of the Re-

duction Division and Related Phenomena ”» Fischer, “A List of

Ohio Plants with Compound Leaves”; York, “ The Agar-agar and

Paraffin Method for Imbedding Plant Tissues” ; Cushman, “ A few

Ohio Desmids.”

The Ohio Naturalist, June: — Development of the Embryo Sac

and Embryo of Batrachium longirostris” ; S[chaffner], * Leaf Expan-

sion of Trees and Shrubs” ; Schaffner, * Key to the Genera of Ohio

Woody Plants based on Leaf and Twig Characters."

The Plant World, March: — Nash, “A Trip to the Inaguas;”

Arthur, “On the Nomenclature of Fungi having Many Fruit-forms " ;

Streeter, “A Treasure Spot of Wild Flowers "; Wiegand, * The Biol-

ogy of Buds and Twigs in Winter."

The Plant World, April: — Nash, “ A Trip to the Inaguas (Conclu-

sion) ”; Arthur, “On the Nomenclature of Fungi having Many

Fruit-forms (Conclusion) " ; Bailey, “Early Wild Flowers " ; Shaw,

“ Botanizing in British Columbia.” i

The Plant World, May:— Greene, “The Earliest Local Flora

[Thalius, 1588]”; Beal, “The Gas Plant." i

Rhodora, April: — Fernald and Knowlton, “ Draba incana and its

Allies in Northeastern America ” ; Woodward, “Some Plants Rare

No. 468.] NOTES AND LITERATURE. 931

or hitherto Unrecorded in Connecticut”; Harper, “ Coastal-plain

Plants in New England”; Terry, ** Mieracium murorum in Massachu-

setts”; Meader, ** Actinella odorata in Maine."

Rhodora, May :— Fernald, * The North American Species of Erio-

phorum —I"; Haberer, ‘Plants of Oneida County, N. Y., and Vi-

cinity — I”; Collins, ** Chlorochytrium lemne in America”; Terry,

* Dicksonia pilosiuscula forma schizophylla in Vermont"; Churchill,

* Three Plants New to the Flora of Vermont.”

Rhodora, June: — Robinson, * Two Varieties of Sisymbrium offi-

cinale in America"; Gilman, “Two Ferns New to the Flora of

Vermont”; Leavitt and Spalding, “ Parthenogenesis in Anten-

naria"; Haberer, * Plants of Oneida County, N. Y., and Vicinity

— I (Continued) "; Hervey, “ Silene conica in New England” ; Cush-

man, “A Contribution to the Desmid Flora of New Hampshire”;

Tilton, “ Scrophularia leporella at Willoughby."

Rhodora, July : — Chrysler, “Reforestation at Woods Hole, Mass.

— a Study in Succession "; Fernald, * The North American Species

of Eriophorum — II”; Setchell, ** Gymnogongrus torreyi”; Wood-

ward, “An Extension of Range of Zatonia pubescens”, Bartlett,

“ Polygonum exsertum in Massachusetts."

Torreya, April: — Harper, * Some Noteworthy Stations for Pinus

palustris? ; Murrill, “ Terms applied to the Surface and Surface

Appendages of Fungi"; King, “Experiment to show that the

Absence of Light alone will prevent the Process of Photosynthesis "' ;

Parish, “Birds and Mistletoe —a Correction”; Cockerell, “ The

Name Melampodium.”

Torreya, May: — Schneider, * The Classification of Lichens ";

Lloyd, * The Course of the Pollen Tube in Houstonia — a Prelimi-

nary Note ";— Reichling, ‘Contributions to the Recorded Fungus

and Slime-mould Flora of Long Island"; Berry, * Three Cotyledons

in Juglans”; Ellis, ** A New Rosellinia [ A. dakeri] from Nicaragua”;

Underwood, “ A Much-named Fern [Microstaphyla moorei),

Torreya, June: — Greene, “Some Ptelea Segregates”; Yatsu,

“Cytological Differences between the Palmella and Filamentous

Forms of Stigeocloneum”; Parish, “Flowering of Yucca australis” ;

Underwood, “ Botrychium silaifolium Presl”; Eggleston, “ Amelan-

chier arguta”; Taylor, * Nature's Engrafting”; Gilg, “ A New Gen-

tian from Bolivia”; Nash, “A Trio of Grasses New to the West

Indies.”

932 THE AMERICAN NATURALIST. (VoL. XXXIX.

The first volume of the new series of “Contributions from the

Gray Herbarium of Harvard University," extending from 1891: to

1903, has been completed by the recent issue of title page, index,

errata, etc., compiled by Miss Day.

The following botanical papers are contained in vol. 19 of the

Transactions of the Kansas Academy of Science: — Sayre, “ Bibli-

ography of the Loco Weed”; Speckman, “ Dissemination and Ger-

mination of Seeds”; Schaffner, “ Myxomycetes of Clay County,

Kansas”; Crevecoeur, “Some Variations among some Kansas Wild

Flowers”; Sayre, *Echinacea Roots”; Baker, “Notes on the Cul-

ture of Wild Flowers.”

The recently issued Sixteenth Annual Report of the Missouri

Botanical Garden contains the following botanical papers : — Hitch-

cock, “The Identification of Walter's Grasses”; Berger, “ A Syste-

matic Revision of the Genus Cereus”; Bush, “The North American

Species of Fuirena,” and “Two New Texas Tradescantias" ; Mac-,

Menzie and Bush, “New Plants from Missouri”; Spaulding, “A

Disease of Black Oaks caused by Polyporus obtusus” ; von Schrenk,

“Glassy Fir,” * On the Occurrence of Peronospora parasitica on Cauli-

flower," and * Intumescences Formed as a Result of Chemical Stimu-

lation"; Hedgcock, “ A Disease of Cauliflower and Cabbage caused

by Sclerotinia," and * A Disease of Cultivated Agaves due to Colleto-

trichum”; Life, “Vegetative Structure of Mesogloia"; Trelease,

“Illustrations of a ‘Strangling’ Fig Tree”; and Harris, “ The Dehis-

cence of Anthers by Apical Pores.”

The Fifth Annual Report of the Michigan Academy of Science con-

tains the following papers of botancial interest : — Beal, “ Michigan

Flora -— Fern and Seed Plants Growing without Cultivation” ; Chase,

“Flora of Michigan — Diatomacee”; Bogue, “The Lichen Genus

Physcia”; Beal, “How I know some of our Trees in Winter” ;

Clark, “The Limits of Difference in Specific and Subspecific Dis-

tinctions.”

The opening fascicle (nos. 1-3) of Montana Agricultural College

Science Studies contains: — Blankinship, “A Century of Botanical

Explorations in Montana”; Blankinship, “Supplement to the Flora

of Montana— Additions and Corrections,” and Blankinship and

Henshall, “Common Names of Montana Plants.”

(No. 467 was issued November 16, 1905.)

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in an unusual degree the qualities of accurate scholarship, simplicity

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text-book.

Lessons in Astronomy, Revised Edition. Manual of Astronomy.

Elements of Astronomy. General Astronomy.

BERCEN’S BOTANIES

BERGEN's botanies were the first to combine a standard text, a prac-

tical laboratory course, and a key for systematic work. The com-

bination of these three things brought them at once into a leading

position among botany texts,—a position they have since maintained.

Elements of Botany, Revised Edition (now ready).

Foundations of Botany.

Notebook to accompany Bergen’s Text-books of Botany or for

general use in Botanical Laboratories.

WILLIAMS’ CHEMISTRIES

In addition to being scientifically accurate, the author's text-books

on chemistry are interesting and attractive.

Elements of Chemistry. Chemical Exercises.

Introduction to Chemical Science. Chemical Experiments.

BLAISDELL'S PHYSIOLOCIES.

_ BLAISDELL’s physiologies have maintained a remarkable popularity

in the educational world. The books present in clear and simple

language the latest and most trustworthy facts on physiology and

hygiene. Special attention is given to the subject of the care and

preservation of the health. Important facts are illustrated by a

series of simple experiments which the pupil can perform with little

or no outlay for apparatus. This feature is peculiar to the Blaisdell

books and has been found no less valuable than original.

Child’s Book of Health.

How to Keep Well. (Revised Edition.)

Our Bodies and How We Live. (Revised Edition.)

Life and Health.

Practical Physiology.

GINN & COMPANY Publishers

BOSTON NEW YORK CHICAGO LONDON