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EX-OFFICIO MEMBERS OF THE EXECUTIVE COMMITTEE

Past Presidents still retaining membership in the Society

R. H. Warp, M.D., F.R.M.S., of Troy, N. Y.,

at Indianapolis, Ind., 1878, and at Buffalo, N. Y., 1879

Avsert McCatta, Ph.D., of Chicago, IIL.

at Chicago, Ill, 1883

T. J. Burritt, Ph.D., of Urbana, IIL,

at Chautauqua, N. Y., 1886, and at Buffalo, N. Y., 1904

Gro. E, Fett, M.D., F.R.M.S., of Buffalo, N. Y.,_

at Detroit, Mich., 1890.

Simon Henry Gace, B.S., of Ithaca, N. Y.,

at Ithaca, N. Y., 1895 and 1906.

A. Ciirrorp Mercer, M.D., F.R.M.S., of Syracuse, N. et

at Pi Pa., 1

A. M. Briere, M.D., of Columbus, Ohio, pes ie

at New York City, 1900.

C. H. E1icenmann, Ph.D., of Bloomington, Ind.,

at Denver, Colo., 1901.

Cuarzes E. Bessey, LL.D., of Lincoln, Neb.,

E. A. Birce, LL.D., of Madison, Wis.,

Henry B. Warp, A.M., Ph.D., of Urbana, IIL,

Herpert Osporn, M.S., of Columbus, Ohio,

at Pittsburg, Pa., 1902.

at Winona Lake, Ind., 1903.

at Sandusky, Ohio, 1905.

at Minneapolis, Minn., 1910.

A. E. Herrzcer, M.D., of Kansas City, Mo., :

at Washington, D. C., rort.

F. D. Hearn, Ph.D., of Philadelphia, Pa.,

at Cleveland, Ohio, 1912.

F. CreiGgHTON WELLMAN, of New Orleans, La,

at Atlanta, Ga., 1913.

The Society does not hold itself responsible for the opinions expressed

by members in its published Transactions unless endorsed by special vote.

TABLE OF CONTENTS

FOR VOLUME XXXIII, Number 1, January, 1914

Relation of the Lichen to Its Algal Host, by Bruce Fink...............

Synopsis of the Conjugate Alge—Zygophyceae, with 62 text figures,

WY Shar st DEBEO Edn ava ciac bak eds tb cepa beueev erica <eyen

Notes and Reviews—Photographic Dark Box for Field Work, with Plate

I; Methods of Preparing Teleost Embryos for Class Use; Preserva-

tion of Bryozoa; Celluloid Covers for Large Microscopic Slides;

Mica Sheets for Carrying Histological Sections; Diatom Collections

at the U. S. National Museum; Notes of Histology and Technic;

Entomological : Notes... i. ss dvccdscestes bene ss swt ascee teen beter eee

Proceedings of the Atlanta Meeting, .. i)... c.cseccececstaveeeeeseueen

Custodian’s Reports 0a cs<edsunbtasdisaeeduatetenendnleraeeeen te

A ROAGUTES 6 REDO. 3 cvois sas edadeabeemeeatantees Hone Go's cad ck Sewer aaeee

TRANSACTIONS

American Microscopical Society

(Published in Quarterly Installments)

Vol. XXXIII JANUARY, 1914 No, 1

THE RELATION OF THE LICHEN TO ITS ALGAL HOST

By Bruce FINK

In a paper recently published, the lichen was defined as a

fungus which lives during all or part of its life in parasitic relation

with an algal host and also sustains a relationship with an organic

or an inorganic substratum. For those who do not care to read

this lengthy paper’, we may summarize briefly regarding the algal

hosts of lichens, their growing together with lichens free in nature,

cultures of lichens with and without the algal hosts, cultures of

algal hosts separately, the growth of lichen hosts and other algae

on media with and without light and CO,., breathing pores and

other means of eration of the algal hosts of lichens, lichens as

carriers of food to their algal hosts, hypotheses regarding the rela-

tion of the lichen to its algal host, and the relation of the lichen

and its host to the substratum.

We have many times found the algal hosts of certain lichens

growing near lichens but not parasitized by them, and have also

more than once seen the spores of lichens germinating and attack-

ing ‘free alge. Schwendener also found free Nostoc colonies,

others penetrated by a few lichen hyphz, and others parasitized

by fully developed Collemas, all growing together, and recorded

about the same relationship between a half dozen other lichens

and their algal hosts. The list of lichens that are known to grow

beside non-parasitized alge of the host species in nature could be

greatly extended, had we space to consider the observations of de

Bary, Kny, Bornet, Zukal, Cunningham, Ward, Peirce, Williams,

Nylander, Fuisting, Stahl, Hedlund and others. It is also well

known that a considerable number of lichens live for months or

1Fink, Bruce. The nature and classification of lichens—lII.

The lichen and its algal host. Mycologia 5:97—166, 1913.

6 BRUCE FINK

years in nature outside the relationship with algz, and all these facts

prove the fallacy of all theories of dual organism, mutualism, con-

sortism, or individualism.

Moller cultivated several lichens on media without the algal

hosts, both from spores and from spermatia. With Calicium pareit-

inum, he produced several successive generations from the sper-

matia produced in spermagones in his cultures. His results demon-

strate that lichens grow about as well on media as do most other

fungi, the spermagones developing in five or six weeks. Bornet

grew several lichens from widely separate families on their various

algal hosts and demonstrated abundantly that lichen spores will

attack these alge and produce thalli. He often found the free

alge growing with others of the same species parasitised by lichens;

and there is no reason to suppose that the spores do not germi-

nate in nature, parasitize alge and produce fully mature lichens

commonly enough. Treub used wild Chlorococcum and also speci-

mens of the same parasitized by several lichens, and found that the

lichens all grew quite as well with the wild algz as with those se-

cured from lichen thalli. This and other similar results should

forever refute the common statement that lichens do not often

attack wild algz, especially when we consider also that lichens

probably almost always grow in proximity with the cosmopolitan

terrestrial alge which so commonly are their algal hosts. Moller

sowed the alga, Chrococcus, on lobes of the Thelephoric ancestor of

Cora and got the lichen Cora. By letting his cultures run for three

or four years, Bonnier got several lichens to produce not only the

sexual organs, but the apothecia as well. Had Moller used lichens

like Endocarpon pucillum or Polyblastia rugulosa, which are known

to produce both sexual organs and apothecia in two or three months

when grown with the algal hosts, very probably he might have

succeeded in getting the apothecia as well as the sexual organs in

his cultures. If there is any doubt in the minds of those who read

whether the lichen should be considered a fungus pure and simple

rather than a dual organism, behavoir like that of other fungi in

cultures with and without the host should be conclusive evidence,

especially when the last doubt about lichen spores attacking wild

alge is removed.

RELATION OF THE LICHEN TO ITS. ALGAL HOST a

Tobler has recently cultivated Xanthoria parietina both with

and without the algal host on beerwort-gelatine. Calcium oxalate

was stored in the lichen tissues when growing alone, but not when

growing with the host. Artari has grown Chlorococcum humicola,

obtained from lichen thalli, on organic media and obtained luxur-

iant growth and dark green color, though the alga was grown in

absolute darkness or in light with CO, excluded. On media con-

taining mineral salts but no organic matter, the alge did not grow

so well. Treboux more recently made similar cultures of about

forty alge and found that approximately half of them can secure

carbon from media containing organic acids in the dark. He con-

cluded that there is no sharp distinction between fungi and these

algze with respect to carbon assimilation. If some one could devise

a way to ascertain whether alge obtain the bulk of their carbon

from the substratum in their natural habitats as they do in cultures,

the problem would be solved, and we could conclude whether the

lichen carries most of the food for the alga growing within it. But

it seems probable that the method of nutrition of alge in nature

is more like that of higher green plants. Hence it seems doubtful

whether the lichen carries much food to the algal host. This view

will be strengthened further when we come to consider the relation

of the lichen to the substratum.

Breathing pores have been postulated for lichens, and various

crude openings in lichen thalli may be readily observed. These are

non-corticate ventral surfaces of thalli, thin cortices at growing

points, thin places with openings on upper surfaces of thalli, cracks

in thalli, soralia, soredia, cyphelle, empty spermagones, isidioid

branchlets, and hollow cylinders in the centres of fruticose thalli.

The last are often in contact with the exterior through dying away

of the basal portions of the branch. Zukal believed that such crude

makeshifts could serve for effective and sufficient zration of the

algal hosts within lichens; but this can scarcely be possible, and

the alga is doubtless placed in a disadvantageous position in lichen

thalli with respect to ration, and may be forced to obtain its carbon

in part through the lichen hyphz from the substratum. We have

taken pains to confirm Zukal’s results by placing crustose thalli and

sections of higher lichens under glycerine to prove the presence of

8 BRUCE FINK

air along certain lines and in certain spots, but have not noted any

pronounced air movements. The eration may suffice for the respi-

ration of the lichen and its host, but is hardly sufficient for photo-

synthesis in the latter. Fnfsttick, Schneider, Rosendahl, Jumelle,

and Zopf have all worked on this problem, but have added little

to what is stated above,

In spite of all hypotheses to the contrary, the lichen seems to

bear a peculiar parasitic relationship to the alga. It is this modified

condition of parasitism, in which the host is unicellular or filament-

ous and is usually surrounded and raised from the substratum by

the parasite, that has obscured the relationship of the lichen para-

site to its algal host. Lichen haustoria withdraw from the algal

cells food elaborated for their own use, while the alge are placed

in a disadvantagous position with reference to light and air and

are carried away from the substratum and imprisoned. The fact

that the lichen may carry some food to the alga does not make

good the disadvantages sustained by the latter. Elenkin, by stain-

ing carefully, found that the dead alge in many lichens examined

exceed the living in number, especially in the algal zone. He thinks

that the lichen secretes an enzyme which kills the alge, which are

afterwards devoured saprophytically by the parasite, and has pro-

posed the hypothesis of endosaprophytism to account for his re-

sults. His studies prove that the lichen is either parasitic or sapro-

phytic on the alga, perhaps partly one and partly the other. Dani-

lov finds that as lichen hyphz enter the algal protoplasts they break

up into delicate networks which penetrate through the protoplasts

in various directions. The walls of these delicate hyphz are very

thin, and food is therefore the more readily absorbed from the

protoplast. The alge become pale and die through parasitism of

the lichen. The researches of Elenkin and Danilov have perhaps

done more to break down the consortium hypothesis than any

other, though that of Peirce is also important.

Several workers have divided fresh water algze into peptone and

non-peptone assimilating alge, but the recent work of Treboux

indicates that if any alge may be regarded as peptone algzee when

growing in lichen thalli or in cultures, these same alge are not

such when living free. Then, if the method of nutrition is changed

RELATION OF THE LICHEN TO ITS ALGAL HOST 9

when the alga is parasitized by a lichen, the change comes about

quickly instead of requiring a long time as has been supposed by

those who have overlooked the fact that parasitization of free

alge by lichens is common.

The relation of the lichen to its algal host cannot be understood

until we know much more about that of the lichen to the sub-

stratum. Passing over the work of Schwendener, Frank and Lotsy,

we may consider that of Lindau, who finds that lichen hyphz do not

penetrate into periderm cells, but spread out between them and

force them apart. The dissolving of periderm cells is not sufficient

to detect with the microscope, but nourishment must be secured

from these cells; for Ascomycetes which do not parasitize algz live

in periderm as well as those that do, and these must secure nourish-

ment. We venture to assert that hypophceodal lichens secure more

nourishment from the periderm cells and little from the algal host

with which they are not closely related. Crustose epiphlceodal

lichens are more closely related to their algal hosts and less closely

with the substratum, and foliose and fruticose lichens penetrate

but slightly into the periderm, while their relation with the algal

hosts is more intimate. Thus the parasitism of the lichen upon the

alga becomes more intense as we ascend the scale of development

of these fungi.

Winter, Zukal, Bachmann, Fiinfstiick, Lang, Friederich, and

Stahlecker have done telling work on the relation of certain lichens

to the rock on which they grow, but the results are conflicting and

uncertain. In general, it seems that lichens or their algal hosts act

chemically on all rocks through substances secreted, affecting basic

more than acid rocks. Here again, just in proportion as the lichen

penetrates into the substratum, does it seem to depend less upon

the algal host, which is then not so abundantly present. The role

of fat abstraction from carbonate-containing rocks needs further

study in spite of several lengthy papers, but Fiunfstuck found that

some lichens can be made to live for years in rocks without their

algal hosts.

Those who wish for a minute consideration of this subject are

referred to the writer’s paper in Mycologia for May, 1913.

ie) BRUCE FINK

SUMMARY AND CONCLUSION

1. Lichens often, and we believe usually, grow where the algal

host lives free; and lichen spores are known to attack the algz in

nature as well as in cultures, just as the spores of other parasitic

fungi attack their hosts.

2. Some lichens grow for months or for years in bark or

rocks outside the relationship with the algal host. Also many fami-

lies and genera of fungi contain some species which are lichens and

others which are not, i. e. some species which grow with alge and

others which do not.

3. Lichens seem to grow as well on wild alge as on those pre-

viously parasitized.

4. The alga is in a disadvantagious position in the lichen

thallus with reference to carbon assimilation, respiration and light,

and is killed by the lichen parasite.

5. The lichen receives more or less nourishment from the

substratum ;—all of it in certain low forms which live in the sub-

stratum, while growing outside the parasitic relation with the algal

host, doubtless much of it in these after entering upon that rela-

tionship; less in other low crustose form that live partly or wholly

on the substratum and sustain a closer relation with the more

abundantly present algal host; still less in higher foliose and fruti-

cose lichens.

6. The conditions of parasitism are peculiar in lichens on

account of the internal host and the partial dependence on the sub-

stratum; but the points given above, in summarizing, prove con-

clusively that the lichen is a fungus pure and simple.

7. Therefore, the lichen may be regarded as a fungus which

lives during all or part of its life in parasitic relation with an alga

and also sustains a relationship with some substratum such as bark,

old wood, soil, rocks or stones, in which or on which it grows.

Miami University

Oxford, Ohio.

SUMMARIES IN MICRO-BIOLOGY

For some months the Secretary has been seeking to secure for this Journal and its

Department of Summaries, a series of papers from biologists dealing with the chief groups

of microscopic plants and animals. It has not been the purpose to present a complete

survey of any of the groups. The wish has been rather to bring together in one article a

statement of the following things:—general biology, the method of finding, the methods of

capture and of keeping alive and cultivating in the laboratory; how best to study; the

general technic; the most accessible literature; and a brief outline of the classification, with

keys for the identification of at least the more representative genera and species of the

micro-organisms likely to be found by the beginning students in the United States.

It has been felt that the getting together of such data as this, while not a contribution

to science, would be a contribution especially to isolated workers and to teachers and stu-

dents in the high schools and smaller colleges.

Papers have already appeared treating the aquatic Oligochetes, the Melanconiales,

the Rusts, the Black Moulds, the Powdery Mildews, and the Cephaline Gregarines. The

following is the seventh paper of the series. It is proposed to have such synopses from

time to time until the more common American species of such groups as the following have

been covered: The Blue-green Alge, non-conjugating Green Alge, Downy Mildews,

Yeasts, other Hyphomycetes, Smuts, Rhizopods, Infusoria, Turbellaria, Bryozoa, Water

Mites, Entomostraca, etc.—[Editor.]

SYNOPSIS OF THE CONJUGATE ALGAE

—ZYGOPHYCEAE

By CHARLES E. BESSEY

A dozen or more years ago the writer prepared a series of

papers on these plants, which were published in volumes 21, 22 and

23 of these Transactions, and now it seems that time enough has

elapsed to warrant another paper dealing with the same group, and

including such revisions as are now made necessary because of our

better knowledge of their structure, and the structure of the nearly

related plants.

The Conjugate Algz are here held to constitute a distinct phy-

lum of chlorophyll-bearing aquatic plants (alge) which have di-

verged from the main evolutionary line from lower to higher alge.

Below them are the Simple Algz (Protophycez), also chlorophyll-

bearing, and still lower than these the Slime Algz (Myxophycez).

The phylum Zygophycee may be characterized as follows:

Plants typically consisting of unbranched, unattached filaments

which easily fragment into short segments, or single cells. Their

I2 CHARLES E. BESSEY

cells contain chlorophyll, but this may be hidden by a brownish

pigment. Their non-sexual reproduction is by the fragmentation of

the filaments into short segments, or single cells, or by the forma-

tion of internal spores. Zoospores are unknown. Sexual repro-

duction is by the union of the protoplasm of pairs of ordinary cells

(isogametes ).

This phylum seems to have originated from the Simple Algz

(Protophyceze) through a physiological sluggishness of the cells,

which resulted in (1) their feeble attachment to one another and

consequent easy and often early fragmentation into few or single

cells, (2) the absence of zoospores, and (3) the reduction of the

sexual reproduction to a sluggish union of the scarcely modified

protoplasm of two vegetative cells. It is thus a group of plants on

the “down grade’, in which all of its members show more or less

of structural degeneration. On account of this sluggishness these

plants are sometimes called the “Lazy Alge”.

They may be separated into two classes as follows:

A. Chlorophyll-green plants with cellulose walls...Class I Conjugate.

B. Mostly brownish plants, with silicified walls................

Class Il Bacilliarioidee

ea ee a ee ee a ee ae ee a eee bt ae ee a

CLASS I. CONJUGATAE

Plants microscopic, typically simple, unbranched rows of cells,

often separating early into isolated cells; cell-walls composed of

cellulose.

Here there are two orders:

I. Cells in long cylindrical filaments.......... Order 1 Zygnematales.

II. Cells mostly solitary by the early fragmentation of the fila-

ment,otten flattened; 34.25 s-6etn swe oe des Order 2 Desmidiales.

Order 1. Zygnematales. Pond Scums’

Filaments elongated, unbranched, cylindrical, with thin, cellu-

lose walls; not rooted, and with two growing ends. Floating at the

surface of the water of quiet pools, rarely in running water,

*In the preparation of these keys and brief descriptions, I have made free use of

the excellent monograph on “The Green Alge of North America’ by Frank S. Collins.

(Tufts College Studies, Vol. II, No. 3). The difficulty of obtaining that work (now

nearly out of print) is the only excuse for this summary presentation.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 13

The three families may be separated as follows:

1. Chloroplast single, long, axial............- Family 1 Mesocarpacee

2. Chloroplasts two, short, axial............. Family 2 Zygnematacee

3. Chloroplasts 1 to 9, parietal, SMitatr ack sare Family 3 Spirogyracee

FAMILY 1. MESOCARPACEAE

The chloroplast is a single flat plate lying in

the axis of the cell, and as wide as, and as long as

18 the cell. The two genera are distinguished by dif-

ferences in the mode of formation of their resting

1. Mougeotia; show-

ing chloroplasts. Spores.

(a) Zygotes formed by the union of cells of different filaments,

or cells of the same filaments.........-.se+eseeees Mougeotia.

(b) Zygotes apparently formed by the union of cells of the same

filament, usually regarded as aplanospores......-. Gonatonema.

MOUuGEOTIA

Cells cylindrical, several times as long as wide;

zygotes formed between the conjugating cells, by

an obvious union of the two protoplasmic units

from two different filaments, or contiguous cells 2. Mougeotia; _ zy:

gote touching

of the same filament. two cells.

Key to the Species

A. Conjugation between cells of different filaments (“scalariform” ).

I. Zygote touching two cells.

1. Filaments 20u or more in diameter,

a. Zygote 50% or more in diameter,

(1) Zygote spherical, in the tube.

(a) Filaments about 50m in diameter... .1. M. crassa.

(b) Filaments about 30 in diameter........-.--

Pita SON ore oid Sect dig i's 2. M. macrospora

(2) Zygote angled........0esececeeeeens 3. M. laetevirens.

b. Zygote less than 50u in diameter,

(1) Zygote wall smooth,

(a) Zygote between the filaments...... 4. M. scalaris.

(b) Zygote projecting into the filaments,

i. Zygotes greenish........ 5. M. sphaerocarpa.

ii. Zygotes, reddish-brown.6. M. minnesotensts.

iii, Zygotes Drown.......0+00+> 7, M. divaricata.

(2) Zygote wall pitted............. sss eeeee 8. M. robusta

14 CHARLES E. BESSEY

2. Filaments less than 20u in diameter.

a. Zygote 40“ or more in diameter,

Cr) -Zygote’ wall smooth sels he cea ee 9. M. delicatula.

(2). Zygote wall verrucose............. 10. M. verrucosa.

(3) Zygote wall with parallel ridges..11. M. glyptosperma.

b. Zygote less than 4ou in diameter,

(1) pZygotecwall Smoothies 64. cee ee 12. M. parvula.

(2) Zygote wall pitted.............. 13. M. nummuloides.

IL.’ Zygote touching ‘three’ celles Foss sackr ue see een 14. M. tenuis.

3. Mougeotia; —_zy- 4. Mougeotia; —_ zy- 5. Mougeotia; end-

gote touching gote touching wise conjuga-

three cells. four cells. tion.

III. Zygote touching four cells,

1. Filaments less than 1ou in diameter,

a. Filaments 6-84 in diameter...............00- 15 M. viridis.

b. Filaments 4-54 in diameter.............. 16 M. elegantula.

2. Filaments Iou or more in diameter,

aueyeote walllonteds cc. .0ass une tie 17. M. quadrangulata.

b. Zygote wall smooth,

(1) Filaments 15-204 in diameter........ 18. M. capucina.

(2) Filaments 10-144 in diameter......... 19 M. calcarea.

B. Conjugation between contiguous cells of the same filament.........

wiaibincnlsia Lote ob lam we Env oie & Ag caus ea DS EINE a habaie te Ne ea 20. M. genuflexa.

1. Mougeotia crassa—Cells 50x 200-500": zygote, 65u.—Florida.

2. Mougeotia macrospora.—Cells 30 x 180-3004: zygotes, 55-6ou.—N. bs ig a

3. Mougeotia laetevirens—Cells 22-40 x 70-300u: zygotes, 40 x 45-60u.—N.

H., Mass.

4. Mougeotia scalaris——Cells 25-30 x 50-1804: zygotes, 30-384.—Mass., N. J.

5. Mougeotia spherocarpa—Cells 20-25 x 60-1504: zygotes, 40u.—N. J., Pa.,

Fla., Calif.

6. Mougeotia minnesotensis—Cells 15-18 x 60-90u: zygotes, 60u.—Minn.

7. Mougeotia divaricata—Cells 20 x 80-200: zygotes, 45u.—Pa.

8. Mougeotia robusta—Cells 25-32 x 75-250u: zygotes, 40-50u.—Mass., N. J.

9. Mougeotia delicatula—Cells 12-14 x 50-80u: zygotes, 20-304.—Canada.

0. Mougeotia verrucosa.—Cells 13-14 x 75-140": zygotes, 40 X 20-25u.—Ala.

11. Mougeotia glyptosperma—Cells 10-15 x 60-180: zygotes, 42-49 X 30-40p.

—Mass., Minn., Fla. Usually referred to Debarya.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 15

12. Mougeotia parvula—Cells 6-10 x 30-1204: zygotes, 8-24u.—‘Pools north,

south, and west”.

13. Mougeotia nummuloides—Cells 8-10 x 40-120p: zygotes, 17-23u.—Me.,

Mass., N. J.

14. Mougeotia tenuis.—Cells 10-13 x 80—200n: zygotes ?—Pa., Fla: N. J.

1s. Mougeotia viridis——Cells 6-8 x 24-804: zygotes PN, elas

16. Mougeotia elegantula—Cells 4-5 x 60-1504: zygotes, 20-40x 12-14u.—

West Indies.

17. Mougeotia quadrangulata.—Cells 8-12 x 50-140u: zygotes, ?.—Mass., N.

1PWSE BF ry.

18, Mougeotia capucina.—Cells 15-20 x 90-280p: zygotes, Pe Mass. Ne):

19. Mougeotia calcarea.—Cells 10-14 x 40-280u: zygotes, 21-50u.—Greenland.

20. Mougeotia genuflexa.—Cells 25-33 x 50-1604: zygotes, ?.—N. Y., Mass.,

Me., N. J.

} GoNATONEMA

Cells cylindrical, several times as long as wide:

zygotes apparently formed by the endwise union of

protoplasmic units of the same filament, usually re-

garded as aplanospores. We have but one species.

6. Gonatonema; 1 Gonatonema ventricosum.—Cells 5-7 X 30-I110u: zygotes,

endwise conju- 22-209 x 13-16u.—Pa., Calif.

gation (?).

FAMILY 2. ZYGNEMATACEAE

The chloroplasts are two short flat somewhat stellate plates

more or less unconnected, and lying in the axis of the cell.

There is but one genus.

ZYGNEMA

Cells cylindrical not much longer than wide: Libis '&

zygotes formed by the union of the protoplasmic fae \

iF,

oF ae

units of cells of two different filaments (scalari- epee)

form), or by the endwise union of the protoplasmic , Zyonema; scala

units of cells of the same filament. Soedteh conju-

Key to the Species

A. Conjugation between cells of different filaments (scalariform).

I. Zygotes formed in the tube between the conjugating cells.

1. Filaments 30u or more in diameter; zygotes brownish......

Eee PERE Cary oth bs kip sty Bish eh Pd 1. Z. pectinatum.

2. Filaments 15-25 in diameter,

a PZyeotes Digish candy. kaw ee eek ile oles 2. Z. cyanospermum.

b. Zygotes greenish or brownish...........+. 3. Z. ericetorum.

16 CHARLES E. BESSEY

II. Zygotes formed in one of the conjugating cells,

1. Filaments less than 25u in diameter.......... 4. Z. leiospermunt.

2. Filaments 254 or more in diameter,

a. Zygotes smooth,

(1) Zygotes bluish in color........ 5. Z. chalybeospermum.

(2) Zygotes brownish in color..............- 6. Z. insigne.

b. Zygotes punctate or pitted,

(1) Zygoted BlOUOSE Fis cies cee enu eee = bho 7. Z. cruciatum,

(2) “ZY GOtED OVONE? eisi cacy ss eb aires 8. Z. stellinum.

B. Conjugation also between contiguous cells of the same

filament.

I. Filaments about 204 in diameter. 4. Z. leiospermum. _

II. Filaments 304 or more in diameter,

1. Zygotes globose, smooth........ 6 Z. insigne. 8. Zygnema; __end-

. : : wise conjuga-

2. Zygotes ovoid, pitted......... 8. Z. stellinum. tion (?).

1. Zygnema pectinatum.—Cells 30-37 x 30-110“: zygotes, about 504.—Mass.,

N. J.

2. Zygnema cyanospermum.—Cells 20 x 40-180: zygotes, 34-404.—Greenland.

3. Zygnema ericetorum.—Cells 15-25 x 15-100“: zygotes, 20-25u.—Me., Massi,

Fla.

4. Zygnema leiospermum.—Cells 20-22 x 20-224: zygotes, 23-304.—Greenland,

Mass.

5. Zygnema chalybeospermum.—Cells 24-27 x 24-80u: zygotes, about 354.—

Calif.

6. Zygnema insigne—Cells 26-30 x 26-604: zygotes, 30-32u.—Mass., N. J.,

Calif.

7. LZygnema cruciatum.—Cells 35-54 x 35-544: zygotes, about 4ou.—Mass.,

N. J.

8. Zygnema stellinum.—Cells 25-36x 25-100“: zygotes, 35-48 x 30-354.—

Greenland, Mass., Conn., N. J.

FAMILY 3. SPIROGYRACEAE

The chloroplasts are 1 to 9 narrow ribbon-shaped bands, which

are spirally arranged in the parietal portion of the cell.

There is put one genus:

SPIROGYRA

With the characters of the family,

Key to the Species

A. Conjugation by the direct union of two cells, without the formation

fia SIO Ts foci a Sou > Ou eee ee cee a aoe 1. S. stictica.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 17

B. Conjugation by a tube from the male cell only; zygote punctate.....

Fe SE a Pe COE be By on) |) Re AN eae pe ae 2. S. punctata.

sil: sb 2a EE

9. Spirogyra; tube- 10. Spirogyra; with 11. Spirogyra; with

less conjuga- tube from tube from

tion, male cell. both cells.

C. Conjugation by a tube from each cell,

I. Cross walls plane,

1. Chloroplast I in each cell,

a. Zygogonia not swollen,

(1) Filaments 20-364 in diameter............ 3. S. longata.

(2) Filaments less than 30u in diameter,

(a) Zygotes about 3ou in diameter....4. S. juwergensii.

(b) Zygotes about 20u in diameter,

i. Cells 3-5 times as long as wide.5. S. communis.

ii. Cells little if any longer than broad......

SANS Saleed da dl aiaiots tev te ile Oe & & 6. S. subsalsa.

(3) Filaments 30% or more in diameter,

(a) Conjugation scalariform.......... 7. S. porticalis.

(b) Conjugation endwise between cells of the

same filament.............. 8. S. condensata.

b. Zygogonia swollen.

(1) Filaments 27-30 in diameter.............. 9. S. affinis.

(2) Filaments less than Zou in diameter,

(a) Zygotes about 30u in diameter,

i. Zygogonia much swollen..10. S. cateneformis.

ii. Zygogonia but little swollen....11. S. gracilis.

(b) Zygotes less than 30u in diameter,

i. Conjugation scalariform....12. S. flavescens.

ii. Conjugation not scalariform; apparently

between cells of the same filament....

I ETA SS Set Pe RR ere 13. S. mirabilis.

(3) Filaments 30 or more in diameter,

(a) Zygotes ovoid or ellipsoid.......... 14. S. varians.

12. Spirogyra; with (b) Zygotes variable, from globular to ellipsoid,

a(cBloroplasts. oblong, pyriform and reniform..15. S. lutetiana.

2. Chloroplasts 2 (rarely 3) in each cell,

a. Filaments 43-50u in diameter.................- 16. S. dubia.

b. Filaments 34-404 in diameter.............. 17. S. decimina.

18 CHARLES E. BESSEY

3. Chloroplasts 3-4 in each cell,

a. Zygogonia not swollen,

(1) Filaments about 100m in diameter,

(a) Vegetative cells swollen..........-- 18. S. jugalis.

(b) Vegetative cells not swollen....19. S. setiformis.

(2) Filaments about 75 in diameter..... 20. S. parvispora.

b. Zygogonia swollen,

(1) Filaments 50-654 in diameter........--. 21. S. ternata.

(2) Filaments 36 in diameter..........-. 22. S. fluviatilis.

4. Chloroplasts 5-10 in each cell,

a. Zygogonia not swollen,

(1) Filaments less than 100 in diameter,

(a) Chloroplasts usually 5.............. 23. S. nitida.

(b) Chloroplasts 7-8, little if at all spirally ar-

Fanwed Avdics sca eh kis a hoe ee 24 S. orthospira.

13. Spirogyra; with (2) Filaments 1oou or more in diameter,

peut. (a) Cells not longer than their diameter........

etd cab cis Wales ke e's ace be 4 25. S. maxima.

(b) Cells usually longer than their diameter......

Slt ogre ia eh ie Rae Rea a 26. S. crassa.

b. Zygogonia swolleny. 2... 0sseucvessietnssemenss 27. S. bellis.

II. Cross walls replicate.

1. Chloroplast 1 in each cell; conjugation scalariform,

a. Zygogonia little if at all swollen,

(1) Filaments 22-284 in diameter............ 28. S. webert.

(2) Filaments 32-36u in diameter.......... 29. S. protecta.

b. Zygogonia swollen,

(1) Filaments less than 2ou in diameter,

GAG LY AL (a) Cells very small, 9-12u in diameter..........

Peed Epis aie ol 2% Rh EE ai pk aeeue cian eae 30. S. tenuissima.

14. Spirogyra; with (b) Cells larger, 15-184 in diameter...... 31 S. inflata.

pamicpte i) (2) Filaments 204 or more in diameter,

(a) Cells very long, Io to 25 times their diameter

cee E Re ehe ld teat tk ae 32. S. spreeiana.

(b) Cells shorter, 3 to 10 times their diameter,

i. Zygotes 42-48u in diameter. ...33. S. quadrata.

ii. Zygotes 26-304 in diameter. .34. S. grevilleana.

2. Chloroplast 1 in each cell; conjugation endwise , between

cells of the same filament............... 35. S. groenlandica.

3, Chioroplasts a.in-eatht cell wu ckay os cea ve eames 36. S. hassallit.

4.: Chieroplasts 3 in ‘each ‘cell (7 on isin eee eee 37. S. insignis.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 19

Spirogyra stictica—Chloroplasts 3-4, nearly parallel; cells 38-54 x 75-200u:

zygotes to 6ou.—Fla., Calif.

Spirogyra punctata.—Chloroplast 1; cells 24-27 x 140-3004: zygotes 36y,

—N., J.

Spirogyra longata.—Chloroplast 1: cells 20-36 x 48-3604: zygotes 20-35u.

—Mass., R. I., N. J., Colo.

Spirogyra juergensii.—Chloroplast 1: cells 24-26 x 60-130": zygotes 30.

—Calif.

Spirogyra communis.—Chloroplast 1: cells 20-25 x 60-1254: zygotes I0-

23u.—Mass., N. J.

Spirogyra subsalsa—Chloroplast 1: cells 22-25 x 22-374: zygotes 18-20n.

—Fla.

Spirogyra porticalis—Chloroplast 1: cells 30-48 x 60-2754: zygotes to

42u.—Mass., N. J., Pa., Iowa, Calif.

Spirogyra condensata.—Chloroplast 1: cells 48-54 x 48-54u: zygotes to

36u.—N. Mex.

Spirogyra affinis—Chloroplast 1: cells 27-30 x 40-90u: zygotes to 30u.—

Jamaica, Alaska.

Spirogyra cateneformis.—Chloroplast 1: cells 24-27 x 48-1504: zygotes

to 30u.—Mass., Calif.

. Spirogyra gracilis—Chloroplast 1: cells 18-21 x 50-Ilo0u: zygotes 30u.—

Mass., Mich.

Spirogyra flavescens.—Chloroplast 1: cells 11-13 x 30-504: zygotes 20u.

—Fla.

. Spirogyra mirabilis—Chloroplast 1: cells 24-27 x 100-270": zygotes 24-

26u.—Me., Wis.

Spirogyra varians.—Chloroplast 1: cells 33-40 x 66-120: zygotes 33-38u.

—Me., Mass., N. Y., N. J., Iowa, Wash., Calif.

. Spirogyra lutetiana.—Chloroplast 1: cells 30-36 x 90-250u: zygotes 30-43u.

—Mass., Wash.

Spirogyra dubia.—Chloroplasts 2 (rarely 3): cells 43-50x65-125u:

zygotes 40u.—Mass., Pa.

. Spirogyra decimina.—Chloroplasts 2 (rarely 3): cells 34-40 x 70-160n:

zygotes 38 x 42-75u.—Mass., Pa., Iowa, Jamaica, St. Croix.

. Spirogyra jugalis——Chloroplasts 3-4: cells 9-100 x 90-150u: zygotes 100-

110u.—Mass.

. Spirogyra setiformis.—Chloroplasts 4: sells 100-110 x 100-I10u: zygotes

96-1004.—Mass., Pa., N. J.

Spirogyra erat hepn del hicebiaats 4: cells 75 x 150-3004: zygotes 50.

—Fla.

. Spirogyra ternata.—Chloroplasts 3: cells 50-65 x 75-1304: zygotes 45- -66m.

—Ill., Colo.

Spirogyra fluviatilis—Chloroplasts 4: cells 36 x 180-2154: zygotes 50-80n.

—Mass., Pa.

23.

24.

25.

26.

27.

28.

20.

30.

31.

32.

33.

34-

35.

36.

37.

CHARLES E. BESSEY

Spirogyra nitida—Chloroplasts 5: cells 72-78 x 100-230": zygotes 60-72.

—Mass., Conn., N. J., Iowa, Cuba.

Spirogyra orthospira—Chloroplasts 7-8, usually straight and parallel :

cells 60-66 x 120-200u: zygotes 72u.—Mass., N. Y., Pa, Minn., Dak.

Spirogyra maxima.—Chloroplasts 6-7: cells 130-140 x 130-1404: zygotes

100-115u.—Pa., Calif.

Spirogyra crassa.—Chloroplasts 4-10: cells 150-160 x 150-320": zygotes

140-150u.—Mass., Pa., N. J., Lowa.

Spirogyra bellis—Chloroplasts 5-6: cells 65-80 x 100-240": zygotes 84-90n.

—-Mass.i.N.. Jy Fa.

Spirogyra weberi—Chloroplast 1: cells 22-28 x 130-450}: zygote 26-30p.

~oMass. N.Y: No jy £2. :

Spirogyra protecta.—Chloroplast 1: cells 32-36 x 120-430u: zygotes 40-42u.

—Mass., Conn., N. J., Mich.

Spirogyra tenuissima.—Chloroplast 1: cells Q-12 x 36-1444: zygotes 30y.

—Mass., R. 1

Spirogyra inflata.—Chloroplast 1: cells 15-18 x 45-144": zygotes 30-36y.

—Mass., Conn., N. J.

Spirogyra spreeiana.—Chloroplast 1: cells 18-21 x 180-5004: zygotes to

36u.—Mass., Wash., Calif.

Spirogyra quadrata.—Chloroplast 1: cells 24-27 x 75-240n: zygotes 42-48.

—— ins NY, Pa.

Spirogyra grevilleana—Chloroplast I or 2: cells 28-33 x 85-3304: zygotes

30-36u.—Mass., N. Y., Ia.

Spirogyra groenlandica.—Chloroplast 1: cells 18-23 x 320-6504: zygotes

34-38 x 100-130u.—Greenland, Mass.

Spirogyra hassallii—Chloroplasts 2: cells 30-35 X 120-280: zygotes 42-

48u.—Mass., Lowa.

Spirogyra insignis.—Chloroplasts 3: cells 38-45 x 150-5404: zygotes to

48u.—N. J., Pa.

Order 2. Desmidiales. Desmids

Filaments rarely elongated, but frequently broken up early into

short segments, or still more commonly into individual cells; in

some cases cylindrical, but more often flattened. Cell walls com-

posed of cellulose, and jointed in the middle, the two ends sepa-

rating easily in fission or conjugation.

The three families may be separated as follows:

1. Cells in longer or shorter unbranched filaments...............

Lie the er NE Ae Pr ORF aie DAs een AT Re OAS Family 4. Desmidiacee.

2. Cells solitary, elongated, little if at all constricted............

CERRO e EY ta a) Salas (hiaid ik Gl ahaliireanaenen eae ear Family 5. Closteriacee.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 21

3. Cells solitary, broad, deeply constricted..... Family 6. Cosmariacee.

NOTE—In the following treatment of the Desmids free use has been

made of an earlier paper of mine on these plants published in Vol. XXII of

the Transactions (1901). As in that paper no attempt is made in this one

to include keys to the very many species.

FAMILY 4. DESMIDIACEAE

Cells in unbranched filaments, from much elongated to shorter

than broad, cylindrical to angular or flattened, and from not at

all to deeply constricted; filaments naked or enclosed in a hyaline

sheath.

Key to the Genera

I. Filaments naked (without a sheath),

a. Cells cylindrical,

tev Chloroplast single; axial is pandas ties we. bias 1. Gonatozygon.

2. Chloroplasts three, parietal, spiral..............- 2. Genicularia.

Lett Olle; DATTOELOUSDEU UG as cabo a eee Cane acd Caemeed Nelcnps 3. Gymnozyga.

c. Cells quadrangular, deeply constricted............ 4. Phymatodocts.

II. Filaments surrounded by a hyaline sheath,

a. Cells not constricted, or very little,

Ti Musientet CULNOTICNS. < 54 ¢ ied end Catewmie as ave ys 5. Hyalotheca.

3° Bilaments’ $- to 4-angular.. i cise ev ccaeescduewes 6. Desnuidium.

b. Cells deeply constricted, filaments flattened,

ree Galles tirirmear sic s 2 be dees As be capienGs os 7. Spherozosma.

2. Cells armed with several divergent horns....... 8. Onychonema.

1. GONATOZYGON

Cells elongated-cylindrical, or truncate-fusiform, attached to

one another in an unbranched filament, which has no sheath, not

at all constricted in the middle; chloroplast one, axial, undulated.—

Small desmids of few species, rarely seen.

2. GENICULARIA

Cells elongated-cylindrical, attached to one another in an un-

branched filament, which has no sheath, not at all constricted in

the middle; chloroplasts three, parietal, spiral, sometimes confluent

or irregular—Small desmids of few species, rarely seen.

3. GYMNOZYGA

Cells oblong, barrel-shaped, each with two median hoop-like

ridges, attached to one another in an unbranched filament, which

RO CHARLES E. BESSEY

has no sheath, not constricted in the middle; chloroplasts of several

axial plates with divergent wings. Small desmids of few species,

several of which are common in quiet waters.

c FF

» 4 { LO YN

a e

15. Gymnozyga; two 16. Hyalotheca; 17. Desmidium; 18. Sphaerozosma;

cells. three cells. three cells, two cells.

one end view.

4. PHYMATODOCIS

Cells oblong, truncate, quadrangular in transection, attached

to one another in an unbranched filament, which has‘no sheath,

deeply constricted in the middle; chloroplasts not known, Small

desmids, rarely seen.

5. HyYALOTHECA

Cells short-cylindrical, attached to one another in an un-

branched filament, which is surrounded by an ample, colorless

sheath, very slightly (obtusely) constricted in the middle; chloro-

plasts of several axial plates with divergent wings. Small desmids

of few species, several of which are frequent in some portions of

this country.

6. DESMIDIUM

Cells oblong, truncate, triangular or quadrangular in cross-

section, little or not at all constricted in the middle, attached to one

another in an unbranched filament, which is surrounded by a

hyaline sheath; chloroplasts of three or four longitudinal plates

lying in the angles of the filament. Small desmids, common

throughout the country.

7. SPH#ROZOSMA

Cells compressed, deeply constricted in the middle, unarmed,

ends rounded or truncate, slightly attached to one another in a

lobed, unbranched filament, which is surrounded by a hyaline

sheath ; chloroplasts quadriradiate——Small desmids, some species of

which are common in ponds and ditches.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 23

8. ONYCHONEMA

Cells compressed, deeply constricted, armed with divergent

horns, ends rounded or truncate, slightly attached to one another in

a lobed, unbranched filament, which is surrounded by a hyaline

sheath; chloroplasts quadriradiate—Small desmids, rarely seen.

FAMILY 5. CLOSTERIACEAE

Cells solitary, elongated, cylindrical to fusiform; transection

circular, not at all, to moderately, constricted ; cells sheathless.

Key to the Genera

I. Cells not constricted, transection circular,

a. Cells straight,

1. Chloroplasts of one or more spiral bands.......... 9. Entospira.

2. Chloroplast a single axial plate............... 10. Mesotenium.

3. Chloroplasts of several axial plates, with divergent wings..

1 CS Bi bes Bee dF IS Sek Sa AA eo Ge Pye, aS 11. Penium.

II. Cells straight, moderately constricted, transection circular.

a. Chloroplasts axial, A

1. Cells short-cylindrical or fusiform, ends rounded, emargin-

PETE TING ee. oe aks sk tne wa Ce mity xo wees Pt 13. Tetmemorus.

2. Cells long-cylindrical, much elongated, ends truncate or

WVTIQRIOLEE OFS S-SOOG 50g ohio 44 bic vin’ Ao uv ba Wd Abie Os 14. Docidium.

Ty, | UC IOTOUMACE FOMINOCCAL oats pce cs eke eb a wna oe eva 15. Pleurotenium.

9. ENTOSPIRA

Cells solitary, sometimes aggregated in a gelatinous matrix,

straight, oblong-cylindrical or fusiform, not constricted in the mid-

dle; transection circular, ends rounded or acuminate; chloroplasts

of one or more spiral parietal bands.—In pools, ponds, and in wet

mosses.

10. MESOTANIUM

Cells solitary, sometimes aggregated in a gelatinous matrix,

short-cylindrical, elliptical or ovate, not constricted in the middle ;

transection circular, ends rounded; chloroplast a single axial plate

or ribbon, sometimes divided in the middle—In pools, on wet

rocks, walls or damp ground.

11. PENIUM

Cells solitary, sometimes aggregated in a gelatinous matrix,

24 CHARLES E. BESSEY

straight, cylindrical, or fusiform, not constricted in the middle;

transection circular, ends rounded or somewhat truncate; chloro-

plasts of several arial plates, with divergent wings.—Large desmids,

II to Sop in diameter, and 6 to Io times as long, common in pools

and springs.

= WA

% 2)

22. Docidium; two

19. Penium; one 20. Closterium; one 21. Tetmemorus; cells and tran-

cell. cell. one cell. section.

12. CLOSTERIUM

Cells solitary, more or less falcate or lunate, incurved (rarely

nearly straight), fusiform or cylindraceous, not constricted in the

middle; transection circular, ends acuminate; chloroplasts of sev-

eral axial plates, with divergent wings.—Medium to large sized

desmids, 3 to 110 in diameter, and from 5 to 20 times as long,

common in pools and springs.

13. ‘TETMEMORUS

Cells solitary, straight, cylindrical, or fusiform, moderately

constricted in the middle; transection circular, ends rounded, nar-

rowly emarginately incised; chloroplasts axial—Rather large

desmids, common in ponds.

14. DocipIUM

Cells solitary, straight, oblong-cylindrical, moderately con-

stricted in the middle, usually long (6 to 30 times their diameter) ;

transection circular, ends truncate, rounded, three-lobed and three-

spined; chloroplasts axial, of two to four radiating bands.—Large

or medium sized desmids, frequent in ponds.

15. PLEUROTANIUM

Cells solitary, straight, cylindrical, more or less

constricted in the middle; transection circular, ends

truncate; chloroplasts parietal—Large desmids,

23. Plewrotaenium; : : :

haan some species of which are common in ponds.

fo Z

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 25

FAMILY 6. COSMARIACEAE .

Cells solitary, broad, more or less flattened ; transection round-

ed to angular, oblong and elliptical, deeply constricted, the half-

cells from entire to many-lobed; cells sheathless.

Key to the Genera

I. Cells short-cylindrical or orbicular, transection rounded or oblong, half-

cells not lobed,

a. Unarmed,

I. Solitary,

(a) Chloroplasts axial, radiating............. 16. Cosmarium.

(b) Chloroplasts parietal, longitudinally laminiform.....

PRLS AREE TS Cotte ee hee CLE PERE eed) 17. Pleuroteniopsis.

2. Joined in gelatinous, branching threads...... 18. Cosmocladium.

b. Each half-cell armed with a spine on each side..19. Arthrodesmus.

II. Cells orbicular, oblong or elliptical, transection flattened or elliptical,

half-cells lobed,

a. Half-cells with few, usually rounded lobes, and broad sinuses

PLR Ate ed tlw vata. SUP wae NUS Oodle Reel ibdats « 20. Euastrum.

b. Half-cells with many pointed lobes and narrow sinuses........

eke Siena hd aka ks a hs bake eRe ae Cede ye 21. Micrastertas.

III. Cells oblong or orbicular, transection rounded or oblong or angular,

a. Armed with spines, chloroplasts parietal, laminiform...........

Rai esas oica tas CLL TR Pada ed chive ete ahies 22. Xanthidium.

b. Smooth, verrucose or hairy, chloroplasts axial...............

PTA ree Gh 8 Bem as Soe eas Re epg am RS 23. Staurastrum

16. COSMARIUM

Cells solitary, short-cylindrical or orbicular, smooth, verrucose,

or rarely spiny, deeply constricted in the middle; transection sub-

oval or oblong, ends rounded or truncate, entire;

C¥ chloroplasts one or two in each half cell, axial, radi-

i is ating.—Mostly small desmids of many species,

24. Cosmarium; one widely distributed and common in mossy ponds.

17. PLEUROTANIOPSIS

Cells solitary, short-cylindrical or rounded, unarmed, deeply

constricted in the middle; transection sub-oval or circular, ends

rounded or truncate; chloroplasts parietal, longitudinally lamini-

form.—Medium to large sized desmids, a few: of which may be

found in our quiet waters.

26 CHARLES E. BESSEY

18. COSMOCLADIUM

Cells joined in gelatinous, dichotomously branching threads,

elliptic-reniform, constricted in the middle; chloroplast one in each

half-cell, central—Small desmids of few species, but one of which

has been found (in spring water) in this country.

19. ARTHRODESMUS

Cells solitary, short-cylindrical or orbicular, smooth, with a

single spine on each side of each half-cell, deeply constricted in the

middle; transection oblong or fusiform-elliptical, ends rounded or

truncate, entire, chloroplasts axial, laminated—Small to very small

desmids, not common.

20. EUASTRUM

Cells solitary, oblong or elliptical, with few rounded lobes and

broad sinuses, smooth or verrucose, deeply constricted in the mid-

es dle; transection oblong or elliptical, ends rounded

Se a or truncate, usually emarginate or deeply incised ;

7: chloroplast one in each half-cell, axial, of longi-

, tudinally radiating threads—Small desmids of

2s. Euastrum; on many species, widely distributed and quite common.

cell. v3 21. MICRASTERIAS

Cells soltary, orbicular, or oblong-elliptical, deeply constricted

in the middle, each half-cell with three to five radi- NO

ating, pointed lobes, separated by (usually) narrow oS LG

section fusiform, ends entire, sinuate or incised;

chloroplasts axial, laminated.—Large desmids, com-

mon in mossy ponds and lakes. +t. aoa

sinuses, the lobes sometimes again divided; tran- = Se

22. XANTHIDIUM

Cells solitary or geminately connected, orbicular, inflated,

armed with spines, deeply constricted in the middle; transection

rounded, oblong or angular, ends neither emarginate nor incised;

chloroplasts parietal, laminiform.—Medium to small sized desmids,

apparently not common.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 27

23. STAURASTRUM

Cells solitary, oblong or orbicular, smooth, verrucose or hairy,

deeply constricted in the middle, each half-cell in transection 3-to-6

or more angular, the angles often prolonged into obtuse or acute

horn-like processes, ends mostly rounded or truncate; chloroplasts

axial—Small desmids of many species, widely distributed but not

abundant.

CLASS II. BACILLARIOIDEAE. DIATOMS

Mostly yellowish-brown plants (by the addition of phyco-

xanthin to the chlorophyll) in unbranched filaments, which are circu-

lar, angled or flattened in cross section (end view, or “valve” view) ;

or more commonly separated early into isolated individuals (some-

times, however, more or less associated together in gelatinous colo-

nies) which are similarly shaped, or variously twisted or bent; cell

wall at first composed of cellulose, early more or less completely

silicified ; the walls of each cell constitute a closed box (“frustule” of

older authors), consisting of two ends (“valves”) and two over-

lapping rings, the “girdle”, and in many cases of “interzones”

(zwischenbinder), which lie between the girdle and the valves;

chloroplasts one or two, large and lamelliform, or numerous, small

and granular; asexual reproduction by the division of the cell so

as to form two similar cells, or by the escape of the protoplasm

from its wall, and the formation of an entirely new wall, or by con-

traction of the protoplasm of a cell and the formation of a new

thick wall (asexual resting spore); sexual reproduction by the

union of the: protoplasmic contents of two cells, resulting in the

formation of one or two new, usually much larger cells.

There are two orders.

A. Filaments commonly cylindrical, usually fragmented into single

CONE Ree re Slee Ct eS BC eeee Order 1. Eupodiscales.

B. Filaments flattened, usually fragmented into single cells......

ORR ME RASA RS RA Se eae eye Order 2. Naviculales.

Order 1. Eupodiscales. Round Diatoms

Cells in transection cylindrical less commonly polygonal or

elliptical, and rarely irregular; ends of cells (valves) marked con-

28 CHARLES E. BESSEY

centrically or radially by dots, areolations, lines or ribs; cells often

with spines, processes or horns.

NOTE. In the following treatment of the Diatoms I have made free

use of my earlier paper on these plants published in vol. XXI, of these

Transactions (1900). No attempt is made here to include keys to the very

numerous species, for whose recognition good drawings are necessary.

Key to the Families

I. Cells short box-shaped or discoid, mostly cylindrical in transection,

usually without horns or projections,

a. Valves not divided into sectors by ribs, sometimes with radial

rows of dots, without “eyes” (round or oval, definitely

bounded, hyaline areas) or nipples. .Family 7. C oscinodiscacee.

b. Valves divided into sectors by ribs, without “eyes” or nipples..

Family 8. Actinodiscacee.

ee @ be e ed 6.6 6 te (ee Cee le8 DIES 19 Be Be 2 8 ROS

c. Valves with radial undulations, or dome-shaped projections,

the latter with “eyes”, nipples or spineS...........+++

Family 9. Eupodiscacee.

es ele aves @ wie epa 0 %e' 68 eo Bea's. 6 0.°94)6 PTS O68) Cee Ss

II. Cells two to many times as long as broad, cylindrical, rarely round-

elliptical in transection; girdle with numerous interzones.....

Family 10. Soleniacee.

oe eign ot Se lee ele ele © Oe eee Oe, oe Se A Re. oe, PS ee ee

III. Cells box-shaped, about as long as broad (rarely much longer),

transection circular to elliptical, with two to many horns much

longer than the cell; interzones rarely present............++-

Family 11. Chetocerotacee.

ene 0d e600 © ow BCR ee OK EC CO CFR 2 Oe 40 60 8 182 9

IV. Cells box-shaped, shorter than broad or but little longer, transection

circular, polygonal or commonly elliptical; valves with two

(rarely one) to more poles, each pole with a projection or

horn which is shorter than the cell, or when about its length

provided with claws; interzones rarely present............--

Family 12. Biddulphiacee.

vy ae ne oe ee ee ee ee ee ee ee ee

V. Cells box-shaped, as long as broad or shorter, elliptical, sometimes

lunate in transection; valves without horns or projections; rarely

with interzones,

a. Valves lunate, without transverse septa..... Family 13. Euodiacee.

b. Valves not lunate,

I. Valves with transverse septa, without spines............

Ae ie Bl aie tas MARE Nata WMA A” Family 14. Anauliacee.

2. Valves without transverse septa, with a marginal row of

SPINES Wiis Rd. 2 yp 3S REE OR SE ERG Family 15. Rutilariacee.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 29

FAMILY 7. COSCINODISCACEAE

Cells short, often in filaments, cylindrical, ends of cells

(valves) not marked by ribs.

Key to the Genera

I. Cells forming filaments, girdle-side marked,

a. Valves without spines,

1. Entire valve uniformly marked...............45- 1. Lysigonium.

2. Margin and center of valve differently marked,

(a) Marginal portion a narrow ring..........+.+++ 2. Paralia.

(b) Marginal portion a very broad radially striate ring,

(1) Central portion finely punctate........ 3. Hyalodiscus.

(2) Central portion areolated............. 4. Hyalodictya.

b. Each valve with a circle of spines............--5- 5. Stephanopy-is.

II. Cells single, girdle-side not marked,

a. Long box-shaped, central portion of valves coarsely areolated..

6. Craspedodiscus.

avail be 6 Os Ble ee, ble We Ae! BORE SROs ae Se PO) BB CEH SE Smee.

b. Cells disk-shaped,

1. Valve markings not consisting of sinuate lines,

(a) Valve with distinct central and marginal portions,

WAHOUT. SPINES fies yc ec cba ae wg erite's sicee ng 7, Cyclatella.

(b) Central and marginal portions of valve grading into one

another, |

(1) Valve with a circle of spines....... 8. Stephanodiscus.

(2) Valve without spines..........--+.++. g. Coscinodiscus.

2. Valve markings consisting of sinuate lines....... 10. Liradiscus.

1. LysloGONIUM

Cells cylindrical (or elliptical), closely joined together, not

CIES=E carinate, sometimes transversely furrowed, some-

times superficially denticulate in the plane of the

fracture, valves simply punctate——Species numer-

27. Lysigonium; ous, in fresh and marine waters.

end view. :

2. PARALIA

Cells cylindrical, valves furrowed parallel to the edge, valve

markings of two kinds, at the center finely punctate, at the edge

a circfe of areole.—Species few, marine and fossil.

3. HyALopiscus

Cells solitary, geminate or several, valves orbicular, with

radiating lines, and with a distinct central smooth umbilicus.—Spe-

cies few, marine and fossil.

30 CHARLES E. BESSEY

4. HyYALODICTYA

Like the preceding, but with the umbilicus closely aerolate.-—

Species one, in fresh waters.

5. STEPHANOPYXIS

Cells cylindrical or discoid (occasionally elliptical in transec-

tion), mostly united in chains, valves tumid convex, hexagonally

alveolate, spines usually coronal, sometimes wanting.—Species

many, marine and fossil.

6. CRASPEDODISCUS

Cells solitary, long box-shaped, valves diversely areolate, cen-

tral portion sharply defined from the surrounding border by a spiny

line—Species few, marine and fossil.

ea:

B11

Elid

28. Stephanopyxis; 29. Cyclotella; end 30. Stephanodiscus; 31. Coscinodiscus;

side view. and side. end and side. end view.

7. CYCLOTELLA

Cells mostly single or in twos, short cylindrical, discoid, valves

saucer-shaped, diversely marked, central portion inflated, smooth

or granulate, surrounded by a circular border marked by fine

radiating lines——Species numerous, mostly in fresh waters.

8. STEPHANODISCUS

Cells single, short cylindrical, discoid, valves circular, slightly

convex, not hexagonally areolate, radially granulate with hyaline

spaces between the radii, center hyaline or granulate, edge with a

simple crown of spines.—Species many, mostly in fresh waters,

some fossil.

9. COSCINODISCUS

Cells single, discoid, valves circular, rarely elliptical or rhom-

boid, flat or centrally depressed, sometimes undulate or plicate,

often with a central hyaline circular or irregular area, which may

contain an areolate rosette; markings areolate or granulate, margin

narrow or broad, mostly with marginal spines.—Species very many,

marine and fossil.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 31

10. LIRADISCUS

Cells single, discoid, with a narrow girdle band, valves circular

to elliptical, somewhat convex, flattened towards the edge, sur-

face sinuate-reticulate, more or less rough, sometimes with small

spines, no central area, margin narrow and hyaline, or broad and

radially lined.—Species few, marine fossil.

FAMILY 8 ACTINODISCACEAE

Cells single, short, cylindrical, the valves divided into sectors

by ribs, without “eyes”.

: Key to the Genera

I. Ribs or sectors without claws,

-a. No sharp separation of central and marginal portions,

1. Radial ribs not transversely connected........... 1. Stictodiscus.

2. Radial ribs connected by transverse lines or rows of

PANIC: rior a oak as oO Sale xtpulery kign eo 2. Hemiptychus.

b. Center areolated and surrounded by a hollow, radially cham-

Maren TISSUE dire Gre die Pk os nk RUE ood a PE Lies 3. Planktoniella.

II. Ribs or sectors with claws,

a. Valve radially undulate, the alternate sectors dissimilar........

eee PS Rear a ce ine bok dared, Bien Vie ih tie 4. Actinoptychus.

b. Valve not undulate,

T=: Rayer alloaliei gs ccpcaw faa ah oie me ss st ia es 5. Asterolampra.

an Onelat ihe rays dissimilar 005.05 ose see ss eke as 6. Asteromphalus.

1. STICTODISCUS

Cells single, discoid, valves circular or angled, more or less

convex (often unequal), with radial ribs usually not reaching to

the center, central area usually granulate-—Species many, mostly

marine and fossil.

2. HEMIPTYCHUS

Cells single, discoid, valves circular, with numerous stout ra-

diating ribs (often alternately longer and shorter), which are con-

nected by transverse lines or rows of granules, center hyaline.—

Species few, marine and fossil.

3. PLANKTONIELLA

Cells single, discoid, flat; valves circular, consisting of a sharp-

ly defined, slightly areolated center, surrounded by a broad, hyaline,

32 CHARLES E. BESSEY

hollow, radially chambered and ribbed border.—Species one, ma-

rine.

4. ACTINOPTYCHUS

Cells single, discoid, valves circular to hexagonal, with radial

more or less dissimilar undultaions, the surface mostly hexagonally

areolate; sectors provided with marginal claws, umbilicus central,

often hyaline and mostly stellate—Species many, marine and fossil.

32. Stictodiscus; 33. Actinoptychus; 34. Asterolampra; 35. Asteromphalus ;

end and side. end and side. end view. end view.

5. ASTEROLAMPRA

Cells single, discoid, flat; valves circular or obtusely angled,

with similar hyaline, radial rays, all reaching the margin and there

provided with marginal claws; center sometimes areolate, margins

always areolate, with a middle non-areolated band between the

marginal band and the center.—Species many, marine and fossil.

6. ASTEROMPHALUS

Cells single, discoid; valves circular or elliptical to oval, with

sub-similar, hyaline, radiating rays, all reaching the margin and

there provided with marginal claws; center hyaline, crossed by

radial zigzag lines, and surrounded by a broad areolated field di-

vided by the rays.—Species many, marine and fossil.

FAMILY 9. EUPODISCACEAE

Cells single, short, cylindrical, the valves with radial undula-

tions, and usually with “eyes”.

Key to the Genera

iso Valwes with fipples, 10° eyes’ <i... sass’ uk wk eee ueee 1. Tripodiscus.

II. Valves without nipples, with “eyes”, ‘ :

a. “Eyes” sub-marginal, small,

1. Valve surface granulate in radiating lines, one “eye”......

Ee CERT Ae Fa Need Vek aaa aee CaS Ree 2. Actinocyclus.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 5S

2. Valve surface mostly areolate, one to four “eyes”’........

LE Mkeee s bal idbmct tse ke RS Wee OP bk Gold eee 3. Eupodiscus.

b.. “Eyes” not marginal, nsually large. iaicete i wtlew ad sin oie ness 4. Auliscus.

I. TRIPODISCUS

Cells single, discoid or box-shaped; valves circular (rarely

polygonal), bearing one to forty-five sub-marginal nipple-like pro-

cesses, flat, crateriform, or with an elevated zone; markings gran-

ular, in straight or crooked lines—Species many, marine and fossil.

39. Rhizosolenia;

36. Tripodiscus ; 37. Actinocyclus; 38. Eupodiscus; end Saar stie ver

perspective. end view. view. view.

2. ACTINOCYCLUS

Cells single, discoid, or short box-shaped; valves circular to

elliptical or rounded rhomboid, flat (rarely convex), granulate,

the granules usually round, and arranged radially; central area

usually round; one round, submarginal “eye’’.—Species many, ma-

rine and fossil.

3. Eupopiscus

Cells single, discoid; valves circular, flat or slightly convex,

center often depressed; markings mostly areolate, without a cen-

tral area, “eyes” one to four, small, near the margin; spines small,

few to many, sub-marginal.—Species few, marine and fossil.

4. AULISCUS

Cells single, discoid; valves circular, round to elliptical (rare-

ly bluntly angled), flat, with usually two (rarely one, three or

four) truncate, conical processes, each terminating in a large “eye” ;

central area usually present; markings of the surface variable,

granulate, pruinate, to areolate—Species many, marine and fossil.

FAMILY 10. SOLENIACEAE

Cells long, cylindrical, often in filaments.

We have but one genus.

I. RHIZOSOLENIA

Cells long cylindrical, forming chains ; girdle composed of num-

34. CHARLES E. BESSEY

erous scale-like, almost ringed segments; valves unsymmetrical,

oblique to the long axis of the cell; cell-wall but little silicified —

Species many, mostly marine, rarely in fresh waters.

FAMILY 11. CHAETOCEROTACEAE

Cells short, cylindrical or somewhat flattened, usually in fila-

ments, with horns longer than the cells.

Key to the Genera

Lpeivialvesncirciulan (witnn many MOMs. 6 %5 oo akeuis se she 1. Bacteriastrum.

II. Valves elliptical, each with two horns....................2. Che@toceros.

I. BACTERIASTRUM

Cells short cylindrical, usually shorter than broad, forming

chains, with numerous horns arising at the margins of the valves.

Species few, marine.

2. CHETOCEROS

Cells short elliptical, shorter or longer than

broad, forming chains; valves elliptical, each bear-

ing two long horns, girdle bands but little silicified.

—Species many, marine.

40. Chaetoceros; |

one cell, side

view. FAMILY 12. BIDDULPHIACEAE

Cells short, cylindrical, polygonal, or commonly more or less

flattened, often in filaments or loose chains, with horns shorter than

the cells.

Key to the Genera

I. Projections or horns without claws,

a. Valves alike,

1. . Valves tri- to multipolar, with a projection at each angle,

(a) Strongly silicified, without spines or claws..1. Triceratium.

(b) Weakly silicified, a stout spine at each pole...........

SELENA Rc nS Los Sn gee eee Lee eee aie ea 2. Lithodesmium.

2. Valves bipolar,

(a) With spines, strongly silicified,

(1) Projections strongly developed......... 3. Biddulphia.

(2) Projections reduced, each bearing a slender spine

SP Ae ad Lane Wea tha aes ha ay letra ie meas 4. Zygoceros.

(b) Without spines, weakly silicified............. 5. Eucampia.

D,'s Valves ianlike ence ero Ce gait ee Bier olyrit ye: 6. Isthmia.

IT... Projections or horns with’ terminal claws. ..........0.00.. 7. Hemiaulus.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 35

I, TRICERATIUM

Cells prismatic, box-shaped, free or connected in chains; valves

three to many angled, angles more or less prolonged into protuber-

ances, without spines or claws.—Species many, nearly all marine

and fossil.

2. LITHODESMIUM

Cells prismatic, box-shaped, united into long chains, valves

three angled, each angle with a stout terminal spine; girdle band

of many scale-like segments; cell walls incompletely silicified—Spe-

cies few, marine and fossil.

3. BIDDULPHIA

Cells box-shaped, elliptical to subcircular in transection, free

or connected in chains; valves usually strongly con-

vex, bipolar, each pole with a short protuberance or

- @& stout horn, which is rounded or truncate; valves

at. Biddulphia; two frequently with stout spines.—Species many, ma-

ells, sid : 5

Re SY ie rine and fossil.

4. ZYGOCEROS

Like Biddulphia, but with the protuberances of the valves

reduced, and bearing a slender spine-like or thread-like horn.—

Species few, marine and fossil.

5. EUCAMPIA

Cells short, slightly curved, forming spiral chains; valves ellip-

tical, flat or with two protuberances ; girdle band mostly with many

cross-lines; cell walls weakly silicified—Species few, marine and

fossil.

6. IsTHMIA

Cells box-shaped, mostly longer than thick, and

broad, trapezoidal, free or united into tree-like col-

onies ; valves elliptical, dissimilar, each with a pro-

42. Isthmia; several

tuberance; girdle band distinct——Species few, ma- cells, side

rine and fossil tached.

Cells box-shaped, mostly longer than thick, and broad, trape-

zoidal, free or united into tree-like colonies ; valves elliptical, dissim-

ilar, each with a protuberance; girdle band distinct—Species few,

marine and fossil.

36 CHARLES E. BESSEY

7. HEMIAULUS

Cells mostly box-shaped, transection elliptical to multiangular,

with relatively long protuberances, united into chains; valves bi- to

multipolar, each pole extended into a short or long horn, terminating

in one or more claws.—Species many, marine and fossil.

FAMILY 13. EVODIACEAE

Cells short, single, lunate in transection, without transverse

septa.

We have but one genus.

1. HEMIDISCUS

Cells box-shaped, single; valves lunate, mark-

ings areolate or granulate——Species few, marine

and fossil. 43. Hemidiscus;

perspective.

FAMILY 14. ANAULIACEAE

Cells short, single or united into loose chains, lunate in transec-

tion, with transverse septa, without spines.

Key to the Genera

I. Valves with transverse septa appearing in girdle view as straight, in-

complete partitions,

Ae MALU OS «SER AME t or bl Galas bie aie Wn enue en ace oe 1. Anaulus.

bit Valves: slightly: Curved uikti.obo poe a ne a ees 2. Eunotogramma.

II. Valves with transverse septa appearing in girdle view as bent, incom-

plete partitions,

a. Incomplete partitions bent-capitate...............00-- 3. Terpsinoe.

b. Incomplete partitions, after bending, elongated parallel to the

WalVOntace. tig how ox ee lowe eae Ree We Ae ae co ee 4. Porpeia.

1. ANAULUS

Cells box-shaped, single; valves elliptical, straight, with two

transverse septa, which appear as straight, short, incomplete par-

titions in the girdle view; valve markings punctate.—Species few,

marine and fossil.

2. EUNOTOGRAMMA

Cells as in Anaulus, but the valves slightly curved, and with

two to many transverse septa.—Species few, marine and fossil.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 37

3. TERPSINOE

Cells box-shaped, single or united into chains by their angles or

valve-faces; valves symmetrical, oblong-elliptical, with lateral undu-

lations, and with two to many transverse septa

"p02 which in girdle view appear as short, incomplete

- partitions with thickened curved ends (resembling

“notes” of written music).—Species few, fresh-

44. Terpsinoe; end ; ,

Lid ies ye water, marine and fossil.

4. PorRPEIA

Cells box-shaped, single; valves oblong-elliptical, the middle

and ends swollen, with two transverse septa which in girdle view

appear as incomplete partitions, which soon bend axially parallel to

the valve-face.—Species few, marine and fossil.

FAMILY 15. RUTILARIACEAE

Cells short, united into short chains, not lunate in transection,

without transverse septa, with a marginal row of spines.

We have but one genus.

I. RUTILARIA

Cells much broader than long, in valve view

oblong-elliptical, united into short chains; valves

boat-shaped, somewhat elevated at the ends, sur-

rounded by tooth-like spines.—Species few, marine 45. ploy a per-

and fossil.

Order 2. Naviculales. Flat Diatoms

Cells in transection narrowly elliptical to linear, less commonly

broadly elliptical, lunate, cuneate or irregular; valves marked pin-

nately or transversely by dots, areolations, lines or ribs; cells with-

out spines, processes or horns.

Key to the Families

I. Rachis of the valves (i. e., the line between the divergent pinnate

markings) evident as a narrow unmarked strip (pseudoraphe),

rarely wanting; valve without a slit (raphe),

a. Cells usually little shorter than broad or longer, with numer-

ous interzones, mostly united into filaments..............

EP MER its ioe ty, etn BE te ERE at POOL Family 16. Tabellariacee.

38 CHARLES E. BESSEY

b. Cells prevailingly much shorter than broad (“rod-shaped” of older

authors, the longer axis of the rod representing one of the

transverse axes of the cell), often united into filaments,

1. Cells cuneate in girdle view (i. e., valves not parallel),

rachis median, interzones present.............0ee00.

SEU ARDS Perks hy Ament pet Family 17. Meridionacee.

2, Cells rectangular in girdle view, or if cuneate the rachis

not median, interzones present or absent.............

bs MOR Se rea lane Gatete wi heh ota as Family 18. Fragilariacee.

II. Rachis containing an elongated slit (raphe) through the cell wall,

a. Rachis commonly median, often more or less lateral, not

keeled or when keeled not punctate, interzones present or

ADSERE LU ay Cacoucn varl\ath Way bk we IK bate Family 19. Naviculacee.

b. Rachis lateral, less often median, punctate-keeled, raphe not

plainly VisiblesL Als sedate pete abe Family 20. Bacillariacee.

III. Rachis evident as a narrow, unmarked strip, or keeled; valve with

two lateral wing-keels, each enclosing a raphe..............

Family 21. Surirellacee.

aeons bia Bava 85 24 eS SC Se 6 VI 8 2 eee we ee as 8S eV

FAMILY 16. TABELLARIACEAE

Cells usually little shorter than broad, or longer, mostly in fila-

ments: rachis of valve a narrow, unmarked strip, without a slit.

Key to the Genera

I. Transverse ribs of the valves, when present, not extending into the

cell cavity,

a. Valves with a few prominent transverse ribs......... 1. Tetracyclus.

b. Valves transversely striate only,

1. Interzones two to many, septa not undulate,

(a) Valves coarsely striate, pseudoraphe present........

cd Wee cece lek hus Ss ANE aie Wisin are elec 2. Rhabdonema.

(b) Valves finely striate, pseudoraphe absent..... 3. Striatella.

2. Interzones two, septa undulate.............. 4. Grammatophora.

II. Transverse ribs of the valves extending deeply into the cell cavity

Cre a Gh MG PREIS bie fhe Ma cigtals aah RM bee aRReedet CNMI tee 5. Denticula.

I. TETRACYCLUS

Cells united into flat filaments, shorter or longer than broad,

with many interzones, and centrally perforated transverse septa;

valves elliptical to oblong, swollen in the middle, without prominent

median line, no nodules, and sparingly transverse ribbed.—Species

few, fresh-water and fossil.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 39

2. RHABDONEMA

Cells united into flat filaments, shorter or longer than broad,

the filaments basally attached by a gelatinous cushion on one corner

of the end cell; interzones many, externally cross-marked, their

transverse septa variously perforated; valves elliptical or linear-

lanceolate, with a pseudoraphe, and transverse-beaded lines and no

nodules.—Species few, marine and fossil.

3. STRIATELLA

Cells shorter or longer than broad, united into

<= _~-_—iflat filaments which may partly separate into zigzag

chains, basally attached by one corner; interzones

few to many, each with an alternately perforated

septum; valves linear to elliptical-oblong, more or

46. Striatella; end less swollen centrally and at the ends; without pseu-

<The rope doraphe or nodules; surface transversely striate,

not ribbed.—Species many, fresh-water, marine and fossil.

4. GRAMMATOPHORA

Cells shorter than broad, united into flat, zigzag

chains, basally attached; interzones two, each with WF

an undulate, centrally perforated transverse sep- 47: pipretnipings taf 6

tum; valves linear to elliptical, sometimes swollen view.

in the middle and sometimes at the ends also, with a faint pseu-

doraphe, and polar but no central nodules, mostly finely cross striate.

—Species many, marine and fossil.

5. DENTICULA

- Cells free, single or united into very short, flat filaments ; inter-

zones two, each with a transverse septum with a row of perfora-

tions; valves lanceolate, without raphe, with transverse ribs and

strie.—Species few, fresh-water, brackish water, and fossil.

FAMILY 17. MERIDIONACEAE

Cells generally much shorter than broad, cuneate in girdle view,

often in filaments ; rachis of valve a narrow unmarked strip, without

a slit.

; Key to the Genera

I. Valves punctate or variously punctate-striate, without transverse ribs,

BP Ober SUALIECL) Sr 5a oS bos he er cee kets etn sooo T ee eens 1. Sceptronets.

AO CHARLES E. BESSEY

b. Cells stalked,

1. Each interzone with a septum only at its broader end......

sats Wedel Alok disp Shoat ati lana etae (6 Gk SRD ee Ata a ae 2. Licmophora.

2. Each interzone with a scalariform-fenestrate septum......

MEENA NER EE Py ane CREEL ee er Se eet AS 3. Climacosphenia.

II. Valves finely transverse-striate and with transverse ribs..... 4. Meridion.

I. SCEPTRONEIS

Cells free, mostly single, cuneate in valve and girdle view;

interzones wanting; valves transversely moniliform-striate, with

pseudoraphe which is sometimes very broad; polar nodules some-

times recognizable.—Species few, fresh-water, marine and fossil.

2. LICMOPHORA

Cells stalked, single or forming fan-like chains,

cuneate in valve and girdle view; interzones two,

open at the narrower end and with a septum at

48. ‘at the broader end; valves very finely transversely

side (upper) striate, and with a pseudoraphe; nodules wanting.

and end view ;

(lower). —Species many, marine.

3. CLIMACOSPHENIA

Like Licmophora, but the interzones with scalariform-fenes-

trate septa—Species few, marine and fossil.

4. MERIDION

Cells free, united into fan-shaped or spiral chains, cuneate in

valve and girdle view; interzones wanting; valves

cuneate, rounded at the ends, with transverse ribs,

and fine, transverse, centrally interrupted striz,

this interruption forming a pseudoraphe.—Species

few, in fresh waters. 49. Meridion; end

and side.

FAMILY 18. FRAGILARIACEAE

Cells generally much shorter than broad, generally rectangular

in girdle view, often in filaments; rachis of valve a narrow unmarked

strip, without a slit.

Key to the Genera

I. Rachis median,

a. Valves with transverse ribs, or if not ribbed, with a central “eye”,

Iva: Without aicentraliteyer ccs a ice ee 1. Odontidium.

a Wath s central eye e. co nyc a dah ee cee teil 2. Plagiogramma.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 41

b. Valves without transverse ribs, without a central “eye”,

I. Ends of valves alike,

(a) Cells in filaments, or zigzag chains,

(1) Valves flat, without polar nodules........ 3. Fragilaria.

(2) Valves raised at the ends, and often in the middle,

with: polar nodulégitis yb. dees ce 4. Dimerogramma.

(b) Cells single, or forming fan-like, stalked clusters.....

LARA Ve DPR SER ELS see tel Coane 5. Synedra.

2. Ends of valves unequally swollen............... 6. Asterionella.

II. Rachis near one margin,

a. Ends of valves alike,

1. Pseudoraphe and central nodule evident.......... 7. Ceratoneis.

2. Pseudoraphe and central nodule not evident......... 8. Eunotia.

Pe eae hs VAIVOS “NNER. ood cac ind i has Ae ce ak ek $a eed 9. Tibiella.

I. ODONTIDIUM

Cells united into short bands or zigzag chains, which are at-

tached at the base, not cuneate, girdle view oblong-rectangular ;

valves lanceolate to linear with transverse ribs, and fine transverse

strie, the latter interrupted centrally by the indistinct pseudoraphe;

no central nodule.—Species few, in fresh waters.

2. PLAGIOGRAMMA

Cells often united into chains, free, not cuneate, girdle view

oblong-rectangular ; valves linear or elliptical, transversely punctate

striate and sometimes ribbed, with a central “eye”; pseudoraphe

often present; terminal nodule present.—Species many, marine and

fossil.

3. FRAGILARIA

Cells united into mostly ribbon-shaped, rarely

zigzag, chains, not cuneate, girdle view rectangular,

mostly narrowly linear; valves linear-lanceolate or

fusiform, flat, transversely striate or with trans-

verse rib-like, beaded markings but no true ribs;

50. Fragilaria; sev- ;

eral cells, end Pseudoraphe present; no nodules.—Species many,

and side. : ‘

fresh-water, marine and fossil.

4. DIMEROGRAMMA

Cells united into ribbon-like chains, not cuneate, girdle view

rectangular; valves lanceolate to linear-lanceolate, sometimes

broader or narrower in the middle, not flat, raised at the ends, and

42 CHARLES E. BESSEY

often in the middle, with coarse or fine transverse-punctate stria~

tions, interrupted by the pseudoraphe ; with polar and often central

nodules.—Species few, marine and fossil.

5. SYNEDRA

Cells free or attached, single or in fan-shaped

clusters, not cuneate, girdle view linear; valves

linear or lanceolate-linear, sometimes somewhat

crinkled, transversely stirate, mostly with a pseu-

doraphe; sometimes with false central and polar

xa 43 1 + 4 31. Synedra; sever-

nodules.—Species many, fresh-water, marine and 5! -s#edra; sive

: and side, at-

fossil. tached.

6. ASTERIONELLA

Cells attached into a star-shaped cluster, not cuneate, girdle

view narrowly linear, with unequally thickened ends; valves nar-

rowly linear with unequally swollen ends, very finely transverse

striate, with a pseudoraphe; no nodules.—Species few, fresh-water

and marine.

7, CERATONEIS

Cells free, single, not cuneate, girdle view linear; valves cres-

centic, faintly or not at all transversely striate ; pseudoraphe present

close to the concave edge; polar and central nodules present.—Spe-

cies few, fresh-water and fossil.

8. EUNOTIA

Cells free or united into chains, or attached,

not cuneate, girdle view rectangular-oblong ; valves

crescentic, often undulate on the convex margin,

transverse striz uninterrupted; pseudoraphe not

sete aes tea evident ; polar nodules present ; central nodule want-

(upper) and j ret - 3 ;

mde tliwexy ee: Species many, fresh-water and fossil.

9. TIBIELLA

Cells attached into fan-shaped colonies, cuneate in girdle view ;

valves curved, with the ends unequally swollen, finely transverse-

punctate-striate, with marginal beads or spines; pseudoraphe indis-

tinct; polar nodules present; central nodule wanting.—Species few,

fresh-water and fossil.

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 43

FAMILY 19. NAVICULACEAE

Cells shorter than broad, rectangular in girdle view, mostly

single, but sometimes connected in chains ; rachis of valve containing

a median elongated slit. |

Key to the Genera

I. Valves parallel,

a. Rachis of valves not keeled,

1. Raphe almost straight,

(a) Raphe with a simple border,

(1) Septa of interzones (when present) not fenestrate,

7. Cells straight in girdle view....... 1. Navicula.

+t. Cells curved,

§. Both valves with a raphe....2. Rhoiconets.

§§. Only one valve with a raphe.........

sae baad aes bo a alert atic 3. Achnanthes.

(2) Septa of interzones fenestrated,

+. Both valves with a raphe........ 4. Mastogloia.

77. Only one valve with a raphe,

§. Interzonal septa narrow, marginal,

FPUESITAIOU ocahunkas oh wae 5. Cocconets.

§§. Interzonal speta complete, fenestrated

Fides Usiasiaca tes Feared 6. Campyloneis.

(b) Raphe bordered by two ridges,

(1) Central nodule small or only slightly elongated

Kae Plata bcs Mare ee Sires oxcaee 7. Brebissonia.

(2) Central nodule much elongated, rib-like........

hind aide WO ikesinl sic btna Mae haa cite eee 8. Amphipleura.

2. Raphe strongly sigmoid or arcuate,

(a) Raphe sigmoid,

OT) “ACAI TUES WESTIE oss ots 0a ac ew cies BAe 9. Gyrosigma.

Ca¥: Gell Swistedin oo x beticcc eras oes Al 10. Scoliopleura.

CUE ate erate ye sa hk ke ok otek tee ewes 11. Toxonidea.

b. Rachis of valves with a keel,

1. Keel (including the raphe) sigmoid, median..12. Amphiprora.

2. Keel (including the raphe) arcuate, excentric..13. Amphitrite.

II. Valves not parallel, ends approximating,

as, Celle mivainit i girdle View <4 os cydce dixie abanues 14. Gomphonema.

De OMS Curved ih Girdle Views oo. gods nee scene es 15. Rhoicosphenia.

IIJ. Valves not parallel, edges approximating,

a. Valves without transverse ribs,

J.) GATE OALTOW, NOT StTIAless. ceo chee oes Pek weactan 16. Cymbella.

it. (oi TOIE DRORG.) BITIALES, Vice ok he ato heh se reee 17. Amphora.

b. Valves with transverse ribs, raphe not evident....18. Cystopleura.

44 CHARLES E. BESSEY

1. NAvVICULA

Cells single, free or enclosed in gelatinous tubes, or rarely

united in chains, not cuneate, elliptical to linear-lanceolate in valve

view, rectangular and straight in girdle view; with or without inter-

zones, interzonal septa not marginally chambered; valves bilaterally

symmetrical, with a straight raphe (or nearly so), no keel, and

round polar and central nodules, the latter sometimes elongated

(stauros) ; surface transversely punctate-striate or ribbed.—Species

very many, fresh-water, marine and fossil.

‘ kd F

OT hn

53. Navicula; end 54. Achnanthes; 55. Cocconeis; end

view. end view. view.

2. RHOICONEIS

Cells single, free, not cuneate, curved in girdle view, interzones

several; valves elliptical-lanceolate, symmetrical, with a straight

median raphe and central and terminal nodules; surface transverse-

ly striate——Species few, fresh-water, marine and fossil.

3. ACHNANTHES

Cells single or forming short chains attached by the basal cell,

cells curved only in girdle view; valves elliptical to lanceolate, often

narrower or broader in the middle; valves dissimilar, the one con-

cave with a true raphe and central and polar nodules, the other con-

vex with a pseudoraphe, both striate with transverse rows of dots,

sometimes ribbed.—Species many, fresh-water, marines and fossil.

4. MASTOGLOIA

Cells mostly enclosed in a gelatinous mass, not cuneate, lanceo-

late in valve view, and oblong in girdle view; valves like those of

Navicula; two interzones present, each having a septum with a

central opening surrounded by a row of rectangular chambers.—

Species many, fresh-water and marine.

5. CoccoNEIS

Cells single, free, straight or curved in girdle view, and the

plane of the upper valve with its margins curved downwards;

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 45

valves round-elliptical to circular, dissimilar, the lower concave with

a true raphe and nodules, the upper with a pseudoraphe and without

nodules, both transversely punctate-striate; interzone one with a

narrow marginal fenestrated septum, or none.—Species many, fresh-

water, marine and fossil.

6. CAMPYLONEIS

Cells single, free, curved in girdle view, and the plane of the

upper valve with the margins curved downwards; valves scutelli-

form, dissimilar, the lower concave, transversely punctate-striate,

with a straight raphe and central nodules, the upper convex, crib-

rose-punctate, with a pseudoraphe and without nodules; interzone

one, between the lower valve and the girdle, its septum complete,

fenestrated.—Species few, marine and fossil.

7. BREBISSONIA

Cells single, free or enclosed in gelatinous tubes, or sometimes

stalked, not cuneate, elliptical to linear-lanceolate in valve view,

rectangular and straight in girdle view; without interzones; valves

bilaterally symmetrical, with a straight raphe (or nearly so) which

is enclosed between two parallel ridges; central nodule small, usually

slightly elongated; surface transversely punctate-striate or ribbed.—

Species few, fresh-water and marine.

8. AMPHIPLEURA

Cells single, free, or enclosed in gelatinous masses or tubes, not

cuneate, narrowly lanceolate in valve view, narrowly oblong in gir-

dle view ; valves bilaterally symmetrical; raphe straight, bordered by

two parallel ridges, and separated by the long, narrow, longitudinal,

rib-like central nodule; polar nodules small; surface transversely

striate—Species many, fresh-water, marine, and fossil.

9. GYROSIGMA

Cells single, free or rarely enclosed in gelatinous tubes, not

cuneate, straight and oblong-elliptical in girdle view,

sigmoid in valve view; valves bilaterally symmet-

rical, sigmoid-lanceolate; raphe median, sigmoid; PS Ere eee he

central nodule small; striations crossed obliquely ia

(decussate) or at right angles (rectangular), reaching almost to the

46 CHARLES E. BESSEY

raphe.—Species many, mostly marine, some in fresh waters, also

fossil.

10. SCOLIOPLEURA

Cells single, free, twisted, not cuneate, girdle view oblong, the

girdle oblique; valves elliptical, strongly convex, the raphe sigmoid,

excentric; aentral nodule small; surface transversely striate, some-

times obliquely striate-pearled—Species few, fresh water, marine,

and fossil.

11. TOXONIDEA

Cells single, free, not cuneate, twisted, lunate or arcuate in

valve view, the girdle oblique; valves unsymmetrical, with an arcuate

excentric raphe, and central and polar nodules; striations decussate.

—Species few, marine.

12, AMPHIPRORA

Cells single, free, not cuneate, twisted, lanceolate in valve view

and oblong in girdle view but with a sigmoid girdle; interzones

present; valves convex, with the raphe concealed in a sigmoid emar-

ginate keel; central and polar nodules present; valves transversely

striate, rarely scattered punctate—Species few, fresh water and

marine.

13. MAMPHITRITE

Cells single, free, not cuneate, quite unsymmetrical; valves

reniform, with an arcuate, emarginate, oblique keel at the convex

margin including the raphe central and polar nodules present ; inter-

zones present; striations of valves transverse or irregular.—Species

few, marine.

14. GOMPHONEMA

Cells single, mostly stalked or in gelatinous masses, cuneate in

both girdle and valve views; interzones present; valves bilaterally

symmetrical, often laterally twice indented; raphe straight, with

central and polar nodules, the former sometimes transversely elong-

ated (stauros); surface transversely punctate-striate-—Species

many, fresh water, marine, and fossil.

15. RHOICOSPHENIA

Cells mostly stalked, cuneate in both girdle and valve views,

curved in girdle view; interzones present; valves straight, bilaterally

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 47

symmetrical, transversely striate, unlike; the concave valve with

raphe and central and polar nodules, the other without nodules, and

with a pseudoraphe.—Species few, fresh water and marine.

16. CYMBELLA

Cells single, stalked, (often becoming free) or enclosed in gela-

tinous tubes, oblong and straight in girdle view; no interzones;

valves lunate, not symmetrical; raphe somewhat excentric, arcuate,

rarely straight; central and polar nodules present; surface trans-

versely striate, without ribs.—Species many, fresh and brackish

waters, and fossil.

57. Cymbella; end

(upper) and 60. Bacillaria; side

side view 58. Amphora; end 59. Cystopleura; (upper) and

(lower). and_ side. end and side. end view

17. AMPHORA

Cells single, mostly free, elliptical to rectangular in girdle view;

sometimes with cuneate interzones; valves lunate, not symmetrical ;

raphe excentric, near the concave margin, doubly arcuate; central

nodule rounded or transversely elongated; surface transversely

punctate-striate.—Species very many, fresh water, marine, and

fossil.

18. CYSTOPLEURA

Cells single, rarely in short chains, attached ventrally to other

plants, girdle view oblong to doliiform; interzones present or ab-

sent; valves lunate, internally transversely ribbed, transversely

beaded externally; raphe excentric near the concave margin (by

some considered to be a pseudoraphe).—Species many, fresh and

brackish waters.

FAMILY 20. BACILLARIACEAE

Cells very short, mostly narrowly rectangular in girdle view,

usually connected in loose chains or bands: rachis of valve contain-

ing a lateral, elongated slit.

48 CHARLES E. BESSEY

Key to The Genera

Ter Keel: median iiss yeh 4 v6c0 Ss win Bela. Siew hd bee, Mia Omines 1. Bacillaria.

HS Reel atone! ddgev iia. s<26 ak wie sae ans ee Came a ee 2. Homoeocladia.

I. BACCILLARIA

Cells parallel, in free chains, gliding upon one another in the

chains, rod-shaped, straight, rhombic in cross section; valves linear,

pointed, with a median, beaded kell in which is concealed the raphe,

transversely striate——Species few, fresh water and marine.

2. HoMOEOCLADIA

Cells mostly free, rarely in tubes or chains, sometimes stalked,

elongated or linear, rarely cuneate, rhombic in cross section;

valves linear to lanceolate, pointed, with-the oblique, bordered keel

at one edge enclosing the raphe; surface punctate or transversely

or decussately striate—Species many, fresh water, marine, and

fossil.

FAMILY 21. SURIRELLACEAE

Cells very short, linear, cuneate, elliptical, ovate or nearly cir-

cular in valve view, more or less oblong in girdle view; rachis a

median unmarked strip, with two lateral wing-keels each enclosing

a slit.

Key to The Genera

1) Malvevsuriace rundwlates siya. cadres ween 1 ae ee 1. Sphinctocystis

II. Valve surface not undulate,

a. Valves cuneate, reniform, elliptical or linear............ 2. Surirella

b. Valves sub-circular, saddle-shaped................ 3. Campylodiscus

I. SPHINCTOCYSTIS

Cells free, oblong to linear, straight ; valve surface undulate and

transversely striate, with a beaded keel on each margin, containing

the raphe; along the center of the valve extends a straight pseu-

doraphe.—Species few, in fresh and brackish waters.

2. SURIRELLA

Cells free or stalked, straight or twisted, in

valve view cuneate, reniform elliptical or linear,

girdle view cuneate, elliptical oblong or sigmoid;

61, Sue gD eng Valves with a beaded or ribbed keel on each margin

and side, at- pals ; . 3 :

a aA containing the raphe; surface with ribs extending

SYNOPSIS OF THE CONJUGATE ALGAE—ZYGOPHYCEAE 49

from the. margin towards or to the median linear or lanceolate pseu-

doraphe.—Species many, fresh water and marine.

3. CAMPYLODISCUS

Cells solitary, free, disk-shaped, disk twisted or

saddle-shaped, round elliptic; valves round elliptic,

with short mostly radiate ribs, and a marginal keel

concealing the raphe; pseudoraphe median, but at

right angles in the two valves.—Species many, most-

ly marine, a few in fresh waters.

2. Campylodiscus;

end view.

DEPARTMENT OF NOTES, REVIEWS, ETC.

It is the purpose, in this department, to present from time to time brief original

notes, both of methods of work and of results, by members of the Society. All

members are invited to submit such items. In the absence of these there will be given a

few brief abstracts of recent work of more general interest to students and teachers.

There will be no attempt to make these abstracts exhaustive. They will illustrate progress

without attempting to define it, and will thus give to the teacher current illustrations, and

to the isolated student suggestions of suitable fields of investigation.—[Editor. ]

A PHOTOGRAPHIC DARK BOX FOR FIELD WORK

The difficulties encountered in doing photographic work in

the field where dark-room conveniences are lacking led to the

making of a “Dark Box” which is an adaptation of the inoculating

chamber in common use in plant pathology. I have found it so

satisfactory that I use it entirely for plate work even in the labo-

ratory where a dark-room is available.

The “Dark Box” (Plate I) is a plain light-tight box 24 inches

long, 18 inches wide and 20 inches high. It is made of light weight

lumber 34-inch in thickness. To avoid:all chances of light enter-

ing, it is made of well seasoned lumber, all corners are joined as

shown in the accompanying diagram at k and all seams in the

sides are made by inserting a strip—‘‘tongue”’—%4x34 inches in

cross section as is shown at m in the diagram. Besides these pre-

cautions all joints are glued as well as nailed. In the right hand end

is a door 14x11 inches for admitting to the box plates, plate tank

and such things as are to be used in the work. In the top and back

are red glass windows 10x8% inches set firmly with putty. The

back one serves to admit light and the top one permits the operator

to see what he is doing in cases where sight is needed. (When

using the windows it is well to cut out side lights by throwing a

focussing cloth over the head. For most work however the win-

dows are covered by wooden doors and the work is done without

sight.) All doors are of the sliding kind and work in a groove as

is shown in the diagram at a and in Plate I, Fig. 3. This shuts out

all light. In front of the box (Plate I, Fig. 1) are two round

holes for the operator’s arms. These are 6 inches in diameter.

52 NOTES, REVIEWS, ETC.

They are 7 inches apart and 6 inches from the bottom of the box

(outside measurement). These are convenient dimensions for an

average sized person. These holes are closed each by two sleeves

with rubber tape at the wrist to draw them tightly about the arms.

The sleeves are 12 inches long and are tapered slightly to eliminate

surplus fullness at.the wrist. The inner sleeves which are tacked

on the inner side of the box about the openings are of black oil-

cloth for protection from chemicals as well as to cut out any pos-

sible light that might have come through the outer sleeves. These

are of fine black sateen and are tacked to the outer side of the

opening (Plate I, Fig. 1). Each sleeve is finished separately with

G h

’ |

j 4

t '

ary

Ls Pe ee

-e-2

----H

Diagram. Section of photographic dark box showing, f funnel for fill-

ing the tank, t water tank, d joint connecting water tank to tipe, b elbows for

excluding light, s faucet for admitting water, c pan for waste, e elbows in

waste tube, g removable section of waste tube, a groove in which doors work,

h finger pulls, k method of joining corners and m method of joining seams.

AMERICAN MICROSCOPICAL SOCIETY 53

a rubber draw-string so that should any light pass the closing of

the outer sleeve it would be cut out by the inner one.

On the top at the left hand end of the box is a cylindrical cop-

per tank for holding water (Diagram, ¢ and Plate 1, Fig. 1, 2 and

3). This is 3% inches in diameter and 18 inches long and is pro-

vided with a funnel (Diagram, f and Plate I, Fig. 1, 2 and 3) above

for convenience in filling. From the tank a short section of 14-inch

water pipe passes into the box where it is bent to form two elbows

(Diagram, b) to prevent the entrance of light. To this pipe is at-

tached a small faucet (Diagram s) through which water can be

drawn as needed. The tank screws onto the pipe (Diagram, d)

so that it can be removed for convenience in transportation.

Directly below the faucet is a copper pan (Diagram, c and

Plate I, Fig. 2) 5x6 inches in diameter and 1% inch deep for re-

ceiving waste liquids. The drain from this has two elbows (Dia-

gram e) as in the tube above. At the bottom of the drain pipe is a

short removable section (Diagram, g) to which a piece of rubber

tubing can be attached to carry the waste to a convenient recep-

tacle.

The doors are fitted with metal finger pulls (Diagram, /) for

convenience in sliding and two metal handles are attached at the

top for lifting the box. The whole is painted inside and out, with

a dull black shellac. It stands on a small table in which there is a

hole to permit the passage of the drain tube. I have found the

most convenient height of the table for use with an ordinary chair

to be two feet. In the field a box or two chairs serves very well

for a support in place of the table.

When filling plate holders the box of plates and the holders

are placed in the dark box and all openings closed. The workman

sits with his arms in the sleeves which are pulled well on at the

wrists and fills the holders in perfect comfort (Plate I, Fig. 4).

In developing the plates the plate tank containing the developer,

the plate cage and the plate holders are placed in the box as before.

When the cage, containing the plates, is safely in the closed tank the

box can be opened until the developing is done, when the tank is

returned to the box where the developer is poured off through the

54 NOTES, REVIEWS, ETC.

drain (Diagram, c). The plates are then washed in several changes

of water which is drawn from the faucet (Diagram, s). Then they

can be taken to the light of the room and placed in the fixing bath.

The box as described is a convenient size for use with 4x5

and 5x7 plates. With a 5x7 plate tank it would be well to make

the water tank slightly larger. The cost, as estimated by the car-

penter who made it, is ten dollars.

Description of Plate I.

Fig. 1. Front view of photographic dark box showing openings for arms

with sleeves attached, funnel and water tank at left and door at

right.

Fig. 2. End view of the same with door removed to show interior of box.

The inlet tube from the water tank and the faucet show above and

the drain pan below. The sleeves show at the left.

Fig. 3. Back view of the above showing windows at top and back partly

open exposing the red glass and door at the end partly open.

Fig. 4. At work at the photographic dark box.

Expa R. WALKER.

METHODS OF PREPARING TELEOST EMBRYOS FOR CLASS USE

Some of the most important features of development of the

teleost egg, such as discoidal cleavage and the part played by the

germ ring in the formation of the embryo, require for their satis-

factory demonstration that the entire egg shall be preserved and

studied as nearly as possible in its natural form. For this purpose

balsam mounts are of little value, for even with the vitelline mem-

brane removed the egg usually collapses in the higher alcohols or

in xylol.

For the convenient handling of cleavage stages to be studied

as opaque objects I have devised the following method: Pieces of

¥% inch glass tubing are sealed at one end by holding in a flame;

a few eggs fixed in corrosive acetic and preserved in formalin are

placed in each tube and the opening plugged with cotton. For these

stages it is well to choose an egg having dark yellow yolk; this will

aid in the differentiation of the snowy white blastodisc. The eggs

may be studied by dropping the tube into a watch glass filled with

water and examining them with a lens; or the tube may be held

Piietenatmaiscn stoic aes

Se re ae

PLATE I.

A PHOTOGRAPHIC DARK Rox

AMERICAN MICROSCOPICAL SOCIETY 55

in the hand and examined with the lens. The special advantage of

the tube is that of ease of manipulation; one can readily secure

any view desired and that without injury to the egg. An additional

advantage is that the method allows little trouble from the inevit-

able mixing of stages that occurs when the material is handled in

bulk by students.

For stages with embryonic shield and germ ring the preceding

method should be used if the yolk is opaque; but a better plan is

to secure the small transparent eggs of the runner (Ctenolabrus)

and mount them in formalin on a hollow-ground slide, sealing the

edges of the cover slip with cement. Staining is not required. In

this egg one is able to view either upper or under surface simply

by changing the focus.

Michigan State Normal College, BERTRAM G. SMITH.

Y psilanti.

PRESERVATION OF BRYOZOA

A method for the preservation of Bryozoa in a well extended

condition was worked out at the University of Michigan Biological

Station during the summer of IQITI.

Care and patience are necessary in the narcotization and killing

of Bryozoa.

The following method was used successfully for preserving

Cristatella, Plumatella and Fredericella.

Chloretone was used for narcotization, and 3% formalin for

killing and subsequent preservation.

The colony was placed in a tube or beaker of convenient size,

and covered completely with water. When the lophophores of the

individual polypides were well extended, the chloretone solutions

were added in the order given below:

1. <A few drops of sat. sol. of chloretone in water.

I part sat: sol. of chloretone to 4 parts of water.

2 parts sat. sol. of chloretone to 3 parts of water.

3 parts sat. sol. of chloretone to 2 parts of water.

4 parts of sat. sol. of chloretone to 1 part of water.

Saturated solution of chloretone.

Aw pS Pp

56 NOTES, REVIEWS, ETC.

The amount of each solution was equal to the amount of water

containing the colony. Each solution was added drop by drop very

slowly. Gradually some of the solution containing the colony was

removed in order to keep the amount constant.

The time required for the application of each solution of chlore-

tone varied from 15 to 30 minutes. After the colony had been in the

saturated chloretone solution for 15 minutes, the killing agent was

added.

A 3% solution of formalin was diluted with a saturated solution

of chloretone, and the following grades were used:

I. I part 3% sol. of formalin to 2 parts sat. sol. of chladetoal

2. I part 3% sol. of formalin to I part sat. sol. of chloretone.

3. 2 parts 3% sol. of formalin to 1 part sat. sol. of chloretone.

4. 3% formalin.

These solutions were added drop by drop in the same manner

as for narcotization, and 15 to 30 minutes were allowed for the ap-

plication of each grade.

Two and one half to five hours are necessary for the entire

procedure. For cristatella the minimum time is sufficient, but for

Plumatella and especially for Fredericella the maximum time is

necessary.

Zool, Lab. Univ. of Lil. BessiE R. GREEN.

CELLULOID COVERS FOR LARGE MICROSCOPIC SLIDES

This method is devised to meet the need of covering serial

sections of large objects, such as advanced embryos. One can reach,

for examination with a compound microscope, every point on slides

measuring 7x3 inches. These may be cut from double thickness

window glass.

Such material as will not permit of being stained in bulk be-

fore embedding can be stained on the slide in a photographic tray

of hard rubber (not painted). Glass covers are not practicable on

such slides; but thin window glass may be used where high powers

are not to be employed. We have recently found that high powers,

including oil immersion lenses, may be used on these large slides by

covering with what is known among the dealers in photographic sup-

AMERICAN MICROSCOPICAL SOCIETY 57

plies as tissue celluloid sheets. These come in sizes to cover three of

the slides of dimensions given above at a cost of fifteen or twenty

cents for three.

These celluloid covers do not seem to show any dissolving

action on the part of the xylol in the balsam, although quite thin

balsam was used on the slides, some of which have been mounted

two months or longer. The celluloid sometimes falls into gentle un-

dulations but not of such a nature as to distort the image seen with

high powers. The celluloid does have a tendency to squeeze the

balsam out at the edges where it curls up. This would make it im-

practical for substitution for the ordinary sizes of covers although

it might be found much cheaper. Whether the celluloid will be-

come darkened after a time as do the sheets of it used in shades and

curtains of automobiles remains to be seen. Perhaps it would be

well to keep it in the dark.

CHAS. BROOKOVER.

MICA SHEETS FOR CARRYING HISTOLOGICAL SECTIONS

Mica sheets may be used with Mayer’s egg albumen adhesive for

carrying sections of paraffin material through the staining process,

after which the mica can be cut into pieces and issued to students

from xylol or creosote ready for mounting in balsam.

This method has been used in Germany, but has not been em-

ployed to the extent it deserves in this country. When the mica

sheets procurable at the stove dealers or hardware store is split into

thin flakes and the fresh surface used, no difficulty is experienced

in getting the sections to adhere. For warming and floating the sec-

tions out smooth, the mica was cut into sizes to fit over a slide. The

remainder of the process of staining and clearing was done with

the mica sheet alone. For a moderate number of students in a class,

a specimen for each can be stained as quickly as a single slide can

be handled. It is well to mount in the balsam with the specimen

uppermost as there may be air spaces between the laminz of the

mica.

Med. Dept. Univ. of Ark. CuHas. BROOKOVER.

Little Rock, Ark.

58 NOTES, REVIEWS, ETC.

DIATOM COLLECTIONS IN U. S. NATIONAL MUSEUM

Dr. Albert Mann has recently been appointed curator of diatom

collections in the National Museum. It is the purpose to make those

now assembled, and others that may be placed here, available to stu-

dents of diatoms. We are coming to realize that diatoms are not

merely interesting objects of study, but are also a fundamental

source of food to animal life.

NOTES ON HISTOLOGY AND TECHNIC

Trichocysts of paramecia: To cause extrusion and staining of

trichocysts add a drop of ordinary fountain pen ink (blue) to the

drop of water on the slide containing paramecia. This may be

done before or after covering with cover-slip. One can readily

watch the extrusion of the trichocysts which are stained a dense

blue. By this method trichocysts are extruded as long bodies.

To stain mesogloea of hydra use a 0.2% aqueous solution of

benzo-purpurin after a hematoxylin stain. Mesogloea is well dif-

ferentiated from ectoderm and mesoderm.

To prepare earthworms for sectioning: Guyer in his text,

Animal Micrology p. 223, advises cleaning out the alimentary tract

by allowing the earthworms to eat moist filter-paper. This proce-

dure is not satisfactory because the cellulose fibers in the paper

tear the tissues in cutting. FE. W. Sink of the Zool. Laboratory

Uni. of Michigan, feeds moist bread for several days, taking precau-

tions to keep the dish and the food clean. Then he narcotizes with

chloretone and kills in any desired agent. Gilson’s mercuro-nitric

fluid has given good results. With this method tearing of tissues in

cutting is avoided.

To kill snails and slugs fully expanded and in proper histolog-

ical condition Harold Cummins gradually stupefies them with hydro-

chlorate of cocaine. The drug is added a few crystals at a time to

the water containing the molluscs. Thirty to sixty minutes are re-

quired for complete narcotization. Restilts are better and quicker

than the old method of drowning. Kill and fix with any approved

agent.

AMERICAN MICROSCOPICAL SOCIETY 59

Labelling microscopic slides. The labelling of microscopic

slides is a burdensome part of slide-making for large classes. Much

drudgery can be saved and greater legibility secured by having

—_—_—_—__———, labels printed with all the desired

Re Hedanirte data. These can be very cheaply

POSTERIOR | and quickly secured in lots of five- | Put slide in

TO CLITELLUM.| hundred or more, printed on good label’ cand” be

stock and well gummed from the | *e@4-

Ornette rae Woodbury Label Co., Woodstock, insedaticht De 7B SES

Vt. The accompanying samples show how these are used in some

laboratories. The use of too much data on a slide label is to be

avoided.

St og yy 8 kd ha

GEORGE R. LARUuE.

ENTOMOLOGICAL NOTES

Gynandromorphous Ants—Professor W. M. Wheeler (Am.

Nat., 48:49-56, 1914.) presents a paper on “Gynandromorphous

Ants Described During the Decade 1903-1913.” This paper is a

sequel to an earlier paper by the same writer (Bull. Amer. Mus.

Nat. Hist., 19 :653-683, 1903) in which six gynandromorphous ants

were described and a review of the seventeen previously recorded

cases was given. The recent paper deals entirely with the findings

of other observers since the writer has not seen additional cases

since 1903. Seven cases of gynandromorphism are reviewed, thus

raising the total number of observed gynandromorphous ants to

thirty. Gynandromorphism occurs very rarely among ants and takes

one of two forms, namely, the gynandromorph, an anomalous indi-

vidual in which the male and female characters are combined in a

blended or more often mosaic manner, and the ergatandromorph, an

anomaly in which the worker characters are combined with those

of the male. The characters of four lateral gynandromorphs, two

ergatandromorphs, and one frontal gynandromorph are reviewed in

this paper. In conclusion Dr. Wheeler discusses a problematical

fossil ant described by Mayr (1868) from Baltic amber and desig-

nated as a gynandromorph. After examining the original specimen

he thinks that it is possible to consider it as an ergatomorphic male

60 NOTES, REVIEWS, ETC.

although the matter is still open to question. The literature from

1908 to date is listed.

The Stable Fly (Stomoxys calcitrans).—Brues (Journ. Econ.

Ent., 6:459-477, 1913) contributes interesting and important data

on “The Geographical Distribution of the Stable Fly, Stomorys cal-

-citrans”’ This insect has attracted considerable attention recently

among entomologists, medical men, and veterinarians owing to the

fact that it has been shown to be capable of transmitting disease. It

is a serious pest to domestic animals and its blood sucking habit

makes it an occasional nuisance to man. It acts as an occasional .

carrier of the bacillus of anthrax and can act as a vector for the virus

of acute epidemic poliomyelitis (infantile paralysis). Likewise there

is a strong suspicion that it transmits other human diseases. Records

of distribution show its presence in thirty-five states, in Canada,

Alaska, Bermuda, Bahama Islands, West Indian Islands, Mexico,

Central America, five countries of South America, three countries

of Europe, throughout the whole of Africa, Canary Islands, Madeira

Islands, southern Asia, Tasmania, New Zealand, Java, Philippine

Islands, and Hawaii. It is apparent that the stable fly is one of

the most widely distributed insects. It occurs generally in the

tropics but almost always in smaller numbers than in cooler climates.

Numerous references are included in this paper.

Bibliographies—Mann (Journal of Animal Behavior, 3:529-

455) gives a list of the “Literature for 1912 on the behavior of ants

and myrmecophiles.” Turner (Journal of Animal Behavior, 3 :401-

428) lists the “Literature for 1912 on the behavior of spiders and

insects other than ants.” These lists include titles relating to any

phase of animal behavior and are very valuable to zoologists and

entomologists who are doing any sort of work in the fields of ani-

mal behavior and animal psychology. The Journal of Animal Be-

havior has published similar bibliographies for the preceding years

and thus constitutes one of the best sources of bibliographical in-

formation on this special field of investigation.

Pau. S. WELCH.

AMERICAN MICROSCOPICAL SOCIETY 61

PROCEEDINGS

of the American Microscopical Society

MINUTES OF THE ATLANTA MEETING

The American Microscopical Society held its annual meeting at Atlanta,

Ga., Dec. 30-31, 1913, in connection with the A. A. A. S. The Executive

Committee met Dec. 30, at luncheon and considered briefly the state of the

Society and laid plans for the improvement of the Transactions.

The business meeting of the Society was held in the Piedmont Hotel,

Dec. 31, at 5 o'clock, Past-President Herbert Osborn in the chair.

In recognition of his distinguished services to the Society in building up

the Spencer-Tolles Research Fund, it was unanimously voted to elect Mr.

Magnus Pflaum to honorary membership.

The Society in the constitutional manner elected the following officers:

President: Professor Charles Brookover, Medical Department Univer-

sity of Arkansas, Little Rock, Arkansas.

First Vice President: Professor Margaret Clay Ferguson, Wellesley

College, Wellesley, Mass.

Second Vice President: Dr. H. L. Shantz, Bureau Plant Industry,

Washington, D. C.

Secretary: T. W. Galloway, Decatur, Illinois.

Elective members Executive Committee: Professor A. D. MacGillivray,

University of Illinois, Urbana, Illinois; Dr. Wm. Litterer, Nashville, Tenn. ;

Professor Howard J. Banker, DePauw University, Greencastle, Indiana.

Members of Council of A. A. A. S.: T. W. Galloway, F. D. Heald.

The reports of the Custodian and Treasurer were read and referred to

an auditing committee consisting of Messrs. MacGillivray, Cort, and Conel,

of Urbana, Illinois.

Society adjourned.

HERBERT Osporn, Chairman.

T. W. GAttoway, Secretary.

62 AMERICAN MICROSCOPICAL SOCIETY

CUSTODIAN’S REPORT FOR THE YEAR 1913

SPENCER-TOLLES FUND

Reported:.at> Cleveland sMechngs sie cc's vs ¢hvw ste ess ap deems acme $3,551.44

Dividends received <luring the ears oess0o. ond seas beds ee een 216.24

Received trom Salesot Aransactions.; /..5 canes sigh ae caddie cece 57.65

$3,825.33

bess Expense: Grant’ Register: (6520 5.4.5 ricands 08a oe eee eee 5.50

CLOLAL SAT FEStEOs ab as 54 29 « eek ores ilere apeigd 4 ben eee $3,819.83

Net increase during the year.............. Cig bat he tau eueeae $ 268.39.

Grand Totals:

FALL CORtHIDUMONS t0 “Galeri. Gow ceils cbivec ieee ousea eur eis $ 700.27

pal Sale yt PransaCtioiiss acon wile ore koe Sees coe + seen ey ee 683.38

AIT ITE SneMmBERSHINS ou. faa oo ak aa ak pelea ae elated BRN 250.00

Aillimterest ant dividendai, uh, ey sas. a ee bee 2,331.68 3,965.33

Less:

All srants oUU scsi bo eee ec ead ep eee ae ee eae $ 100.00

All iite; membership dues paidigsicies Vad nae naceie ene ae 40.00

AL expenses! ic oa ie Be dco ee aie 6 dt Oe eae 5.50 145.50

Wetbalances. hues sve smart EP ak dds oe 20S ee $3,819.83

Macnus Priaum, Custodian.

Life-members and Contributors of $50 and over: John Aspinwall,

Robert Brown, (dec’d.), J. Stanford Brown, Henry B: Duncanson, A. H.

Elliott, John Hately, Iron City Microscopical Society, and Troy Scientific

Association.

We the undersigned committee hereby certify that we have carefully

examined the foregoing account, compared the same with vouchers and

found it to correspond and correct.

A. D. MacGtiivray,

Jesse L. Conet,

W. W. Cort,

Auditing Committee.

AMERICAN MICROSCOPICAL SOCIETY 63

ANNUAL REPORT OF THE TREASURER OF THE

AMERICAN MICROSCOPICAL SOCIETY

December 24, 1912 to December 24, 1913.

RECEIPTS

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BMPS EMT EICITINNET Rats rows. cig kc diana aw Ca ee ace Bee oe ean 96.00

SIGE STRESE Me CLEA C CRE cou PRS FOr Ee id Baba wb Rea RES 144.00

SePEEORI OTIS. CATS COMUNE SEs Ci oy ad kk sone ab ee bed wiles wea ohhh ares 83.00

Sue Peeed Seve TCU PS CIT @ CHIE 0D Sl be a Swi din coe ce ans sre ow big ak ke cca 34.00

SRAGNCEIORIMLON TOK WONG: 34 ci ou L ot ad an Dt ae ES Suk owe Riera dee 8.00

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ee Ger seers: ti) POI: 40s vos c ceseaad wore ak kbs els drhabnd acer 25.00

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EXPENDITURES

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PRee OURICIG Noe ae naa tla My NMS aie eB Se Sure) Lib Iee She Lah wa hate 9.75

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64 AMERICAN MICROSCOPICAL SOCIETY

We the undersigned have this day examined the accounts of T. L.

Hankinson, Treasurer of the American Microscopical Society for the year

1913—-compared the vouchers therewith and found the same correct and

properly cast.

A. D. MacGrLiivray,

Jesse L. Conet,

W. W. Cort,

Auditing Committee.

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ORGANIZED 1878 INCORPORATED 1891

APRIL

1914

VOLUME XXXIII No. 2

TRANSACTIONS

OF THE

AMERICAN

MICROSCOPICAL

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EX-OFFICIO MEMBERS OF THE EXECUTIVE COMMITTEE

Past Presidents still retaining membership in the Society

R. H. Warp, M.D., F.R.M.S., of Troy, N. Y.,

at Indianapolis, Ind., 1878, and at Buffalo, N. Y., 1879

Apert McCatta, Ph.D., of Chicago, Ill.

at Chicago, IIl., 1883

T. J. Burrit, Ph.D., of Urbana, IIL,

at Chautauqua, N. Y., 1886, and at Buffalo, N. Y., 1904.

Gro. E. Feu, M.D., F.R.M.S., of Buffalo, N. Y.,

at Detroit, Mich., 1890.

Simon Henry Gace, B.S., of Ithaca, N. Y.,

at Ithaca, N. Y., 1805 and 1906.

A. Cuirrorp Mercer, M.D., F.R.M.S., of Syracuse, N. Y

at Pittsburg, Pa., 1896.

A. M. Bremz, M.D., of Columbus, Ohio,

; at New York City, 1900.

C. H. E1ceENMANN, Ph.D., of Bloomington, Ind.,

at Denver, Colo., 1901.

Crartes E. Bessty, LL.D., of Lincoln, Neb.,

E. A. Brrce, LL.D., of Madison, Wis.,

at Winona Lake, Ind., 1903.

Henry B. Warp, A.M., Ph.D., of Urbana, III,

at Pittsburg, Pa., 1902.

at Sandusky, Ohio, 1905.

Hersert Ossorn, M.S., of Columbus, Ohio,

at Minneapolis, Minn., 1910.

A. E. Hertzier, M.D., of Kansas City, Mo.,

at Washington, D. C., 1911.

F. D. Heap, Ph.D., of Philadelphia, Pa.,

at Cleveland, Ohio, 1912.

F. CreicHton WELLMAN, of New Orleans, La,

at Atlanta, Ga., 1913.

The Society does not hold itself responsible for the opinions expressed

by members in its published Transactions unless endorsed by special vote.

TABLE OF CONTENTS

FOR VOLUME XXXIII, Number 2, April, 1914

North American Free-living Fresh-water Nematodes, with Plates

A VIEL, iy WN. Ay Cobbsci coal i ccuucwnes ad adit bik Lee 69

Notes and Reviews: Further Notes on Pristina with Description of

Three New Species, by H. E. Hayden; Nematode Parasite of Alli-

gator, with Plate IX, by A. M. Reese; Behavior of Pigment Cells

in Larvae of Amphibians; Behavior of Ectodermic Epithelium ;

Cross Inoculation of Legumes; The Binocular Microscope; Journal

of Micrology; Life-cycle of Hypotrichous Infusoria; Pearl Forma-

tion; Regeneration of Nerves; Behavior of Nucleus in Crystal

Formation; Entomological Notes; Notes on Histology and Technic;

Short Method of Affixing Stained Sections; Mounting Botanical

Material in Sodium Silicate Medium; Stable Solutions of Gentian

Violet; Quick Test for Treponema Pallidum...............-000000. 135

NOTE.

Members will notice (page I of advertising section, and TRANs-

Actions for July, 1913), that grants are now being made from the

income of the Spencer-Tolles Research Fund, for the encouragement

of research with the microscope.

TRANSACTIONS

American Microscopical Society

(Published in Quarterly Installments)

SEE SITAR Shatseemanerceaemee eee RE ee eR SSE ALOR aaa eee

Vol. XXXIII APRIL, 1914 No, 2

THE NORTH AMERICAN FREE-LIVING FRESH-WATER

NEMATODES.

CONTRIBUTIONS TO A SCIENCE OF NEMATOLOGY, II.

Eighty Illustrations

By N. A. Copp.

INTRODUCTION.

The little creatures described in these pages belong to a very

important but as yet comparatively little known class of animal

organisms, the nematodes.

Something more than a mere reconnaissance leads to the con-

clusion that over nine-tenths of the nematode species still remain

unknown, a greater disproportion between the known and the un-

known than exists in almost any other class of organisms.

Nematodes are distributed far and wide in inconceivable num-

bers, and without doubt constitute a group in the animal kingdom

comparable with insects both in number of species and economic

importance, They vary in length from one two-hundredth of an inch

to several feet, though the great majority are less than half an inch

long. They differ from most other slender, wormlike forms in

their lack of locomotive appendages,—the outer surface, except for

the presence of setae, is usually quite smooth. Being more or less

cylindrical in form, they are often called “round-worms.” They

live free in the soil, in fresh and salt water, and are found parasitic

in a great variety of animals and plants.

NEMATODES AS CAUSES OF DISEASE

The parasitic species often cause fatal diseases of plants and

of animals, including mankind. The dreaded hookworm is a nema-

tode. So is that scourge of the tropics, the guinea worm. Trachina,

70 N. A. COBB

costing civilized nations hundreds of thousands of dollars yearly

for the inspection of pork, is a nematode. If trachina-infested or

measly pork be eaten by human beings, the result is a serious, often-

times fatal, sickness, called trichinosis, epidemics of which have

claimed victims by the hundred. Nematodes have recently been

suspected, with good show of reason, of being carriers of cancer.

So the list of serious human nematode diseases might be increased

until practically half a hundred had been enumerated.

No less serious are the nematode diseases of plants and of

the lower animals. The common gall-worm has been found infest-

ing the roots of several hundred different species of plants, among

them most of our cultivated crops, and causes an annual loss

amounting to millions of dollars. There is another nematode that

has at times completely checked the growing of sugar beets in cer-

tain regions. The list of serious plant diseases of this character

could easily be increased to scores. The same is true of animals.

Every domestic, dloubtless every wild, species has a number of

specific nematode parasites sapping its vitality.

WONDERFUL VARIETY OF HABITAT.

Not the least interesting thing about nematodes is the astound-

ing variety of their habitats. They occur in arid deserts and at the

bottoms of lakes and rivers, in the waters of hot springs and in

polar seas where the temperature is constantly below the freezing

point of pure water. They were thawed out alive from Antarctic

ice in the far south by members of the Shackelton expedition. They

occur at enormous depths in Alpine lakes and in the ocean. As

parasites of fishes they traverse the seas; as parasites of birds they

float across continents and over high mountain ranges. Their eggs

and larvae, invariably of microscopic size, are carried from place to

place by an exceedingly great variety of agencies. Almost any vis-

ible thing that moves is capable of transporting nematode eggs or

larvae. Sometimes the eggs and larvae are so resistant to dryness

that if converted to dust they revive when moistened. This

revival of mummified nematodes may take place after as long a

period as a quarter of a century.

Nematodes are found in queer places. The wildest imagina-

tion could hardly outpicture the facts. One species is found prac-

FREE-LIVING FRESH-WATER NEMATODES 71

tically only in the vermiform appendix of man; another has its

adult form only in the seeds of wheat. A third form occurs in

the felt mats on which the Germans are accustomed to set their

mugs of beer, and has been found in no other habitat. On the feet

of birds and insects the eggs, larvae, and adults of certain nema-

todes are carried to the tops of the tallest trees. The sour sap is-

suing from the wounds of a tree, often many feet above the ground,

not infrequently contains nematodes that are specific to the wounds

of that particular kind of tree. The tap water of even well-con-

ducted cities often contains nematodes.

Nematodes are inconceivably abundant. A thimbleful of mud

from the bottom of the ocean may contain hundreds of specimens.

The number of nematodes in the top six inches of an acre of ordi-

nary arable soil amounts to thousands of millions. Statistical cal-

culations relative to the number of nematodes in a single acre of

soil near San Antonio, Texas, U. S. A., disclosed that if they could

start in a procession for Washington, D. C., two thousand miles

away, each close on the tail of the one in front, the head of the

procession would reach Washington before the rear had left San

Antonio. As nematodes are usually very prolific, a single female

sometimes producing thousands of eggs, the number of eggs vastly

exceeds that of the adults.

We must therefore conceive of nematodes and their eggs as

being carried by the wind, and by flying birds and running animals ;

as floating from place to place in nearly all the waters of the earth;

and as shipped from point to point throughout the civilized world

in vehicles of traffic.

There are beneficial nematodes, though knowledge of this phase

of the subject is in its earliest infancy. Some nematodes feed ex-

clusively on their injurious brethren. Others devour baneful micro-

organisms. Their adaptations and relationships appear to be sim-

ilar to those of insects.

NORTH AMERICAN FRESH-WATER SPECIES.

The nematodes here described are the main portion of those

found during a rather casual search for aquatic species that would

serve as the basis of a special chapter in a zoological textbook de-

voted to fresh water organisms. The object of the textbook was

72 N. A. COBB

to characterize each known genus by describing and illustrating a

typical species.

When the work on the nematode chapter was begun there was

hardly a single adequately described North American species, so

that the initial task was one of pure discovery. This was followed

by the work of research and definition, and this finally by that of —

selection and presentation of typical species in a manner suitable

to a college textbook. |

The famous Philadelphian, Dr. Joseph Leidy, appears to be

the only naturalist who had previously attempted to describe any of

- our fresh water nematodes, and even he did but little. I have at-

tempted to rehabilitate his Anguillula longa, which, as Bastian sur-

mised, belongs to the more modern genus Tyrilobus. I have had to

assume that the variety Leidy had before him was that most com-

mon in the ditches, brooks and rivers of the Chesapeake region,

and have given to this form the name Trilobus longus (Leidy)

Bastian.

All the other species proved to be new, some of them repre-

sentatives of new genera. Most of the new genera have already

been described in my contribution to the Proceedings of the Wash-

ington Academy of Sciences, October, 1913.

An aquatic species as here defined is any species inhabiting

either fresh water, or non-brackish swampy soil below the water

table ; hence a species that will not drown in fresh water; a species

fitted to utilize oxygen dissolved in fresh water.

Including those of the present article, the fresh water North

American species so far described are as follows:

Achromadora minima Cyatholaimus truncatus

Actinolaimus radiatus Diplogaster fictor, Bastian

Alaimus simplex Dolichodorus heterocephalus

Anonchus monhystera Dorylaimus fecundus

A phanolaimus minor Ethmolaimus americanus

Aphanolaimus spirurus Tota octangulare

Bastiana exilis Tronus americanus

Cephalobus setosus Mesomermis virginiana

Cephalobus subelongatus Microlaimus fluviatilis

Chronogaster gracilis Monhystera sentiens

Cryptonchus nudus Mononchus similis

FREE-LIVING FRESH-WATER NEMATODES 73

Oncholaimus punctatus Spilophora canadensis

Plectus tubifer Teratocephalus cornutus

Prismatolaimus stenurus Trilobus longus (Leidy), Bastian

Rhabditis punctatus Tripyla lata

Rhabdolaimus minor Tylenchus symmetricus

There has been little time or opportunity to search specially for

these fresh water forms, and the fact that it has been possible in so

short a time to assemble so many genera and species is proof of

the enormous abundance and multifarious nature of these organ-

isms. No doubt there is a horde of species awaiting discovery in

North American waters.

THE NEMATODE FORMULA.

The following diagram illustrates the nature of the formula

used in the tabulation of the various necessary measurements:

Ig eR 688

Fig. 1. Diagram of the descriptive decimal formula used for nematodes; 6, 7, 8, 10,

6 are the transverse measurements, while 7, 14, 28, 50, 88 are the corresponding longi-

tudinal measurements. The formula in this case is:

7, 14. 28. SO. 88.

cg rtky. Luca ages

The unit of measurement is the hundreth part of the length

of the body, whatever that may be. The measurements become,

therefore, percentages of the length. The absolute length is given

in millimeters as a final non-paired term. This decimal method of

presenting the measurements is the most compact and convenient

method, and is being used more and more year by year.

The measurements are taken with the animal viewed in profile ;

the first are taken at the base of the pharynx, the second at the

nerve-ring, the third at the cardiac constriction or end of the neck,

the fourth at the vulva in females and at the middle (M) in males,

the fifth at the anus. The formulae represent the average of sey-

eral specimens whenever possible.

There are several methods of securing the measurements, one

of the most convenient being the preparation of a camera lucida

“skeleton” to scale, consisting of a line following the body axis

74 N. A. COBB

from one end to the other, and diametral lines at the base of the

pharynx, the nerve-ring, the end of the neck, at the vulva in fe-

males and at the middle in males, and finally at the anus. This

skeleton is then measured with a metric scale and map measure,

and the percentages divided out with the aid of a slide rule.

IOTA, Cobb, 1914.

Figiit, Plate 11,

14. 21. 25. -85 92.

1. Jota octangulare, n.sp. 4 mm.

The pe A

Along the longitudinal fields the striz are so modified as to give the

worm somewhat the appearance of being covered by eight rows of relatively

large scales arranged in pairs. Six small, simple, flattish lips surround the

vestibule. The lips are supplied with six small, innervated papillae. These

lie in the midst of a plate-shaped disk, the first annule. There are no recog-

nized traces of amphids, but the recessive nature of the second annule is

suggestive, and it is possible that this peculiarity of the second annule is in

some way connected with the amphids. There are no eye-spots. The narrow

vestibule leads to the equally narrow pharynx, which consists essentially of

a muscular tube closely surrounding the spear. This latter is of relatively

very large size, and strictly Tylenchoid in structure. Its length is about

equivalent to the first twelve annules of the cuticle. It is divisible into two

parts: a long cylindrical hollow shaft tapering to a point near its apex, and

having a length about equivalent to the first nine annules; behind this shaft

a basal portion or “hilt,” which in its distal part has a structure like that

of the shaft, but with a slightly greater diameter. This hilt terminates in a

threefold, flattish bulb about one-fourth as wide as the corresponding por-

tion of the neck. The lumen of the spear is continuous with that of the

oesophagus. This latter consists mainly of a narrow, chitinous tube, which

is usually somewhat coiled when the spear is at rest. That portion of the

oesophagus containing the hilt of the spear and the coiled oesophageal tube

* just mentioned constitutes a somewhat obscure elongated “bulb.” This bulb,

however, is not the morphological equivalent of the bulb usually seen in the

oesophagus of Tylenchus and Aphelenchus, as it has no radial muscles, and

contains no valvular apparatus. The remaining short portion of the oesopha-

gus is tubular and narrow, though it swells slightly at the terminus, where it 1s

about one-eighth to one-ninth as wide as the base of the neck. The ex-

cretory pore empties through the exterior margin of the nineteenth annule,

or thereabouts. It may be distinctly seen when the worm is viewed from

the ventral side, and less distinctly seen in profile.

Habitat: Dismal Swamp, Va. Flemming solution to glycerine.

FREE-LIVING FRESH-WATER NEMATODES 75

RHABDOLAIMUS, de Man, 1880.

Fig. 2, Plate II.

AGi2 15745 S54, S11 as

DAMS Ad Ba ae Te:

The thin layers of the transparent, naked, colorless cuticle appear to be

destitute of any but very fine transverse striations, most clearly visible near the

head. The conoid neck ends in a rounded head which is not set off in any

way. There are no cephalic setae. Careful focussing appears to indicate on

the outer margin of the head the presence of almost invisible papilla-like or-

gans which may perhaps be representatives of cephalic setae. There are no

lips. The amphids are located at a distance from the anterior extremity

about three times as great as the width of the lip-region, and a little more

than twice as great as the width of the head near where they occur. Seen

in dorso-ventral view they have the appearance of obscure openings from

which there leads inward and backward slight refractive elements which

soon become indefinite. Immediately behind the mouth opening there is at

least one obscure refractive element of small size, apparently very much as

figured by Dr. de Man in his description of the type species. The tubular

pharynx is long and slender, extending backward for a considerable distance

behind the amphids. Its total length is probably a little less than one-third

the distance to the nerve-ring, though the limits are not definite in the speci-

mens so far examined. The oesophagus is at first about three-fourths as

wide as the head and continues to have this diameter, or a slightly greater

diameter, until near the end, where it expands to form the pyriform cardiac

bulb which contains an obscure valvular apparatus. This bulb is three-

fourths as wide as the base of the neck. The lining of the oesophagus may

be faintly seen throughout its length. The rather thin-walled intestine which

is separated from the oesophagus by a slight constriction becomes at once

three-fourths as wide as the body. It appears to be composed of cells of

such size that probably only four to six are required to build a circumfer-

ence. From the nearly continuous anus, the rectum, which is somewhat

longer than the anal body diameter, extends inward and forward. The tail

begins to taper from a little in front of the anus and tapers regularly to

the terminus which is armed with a striking, elongated, unarmed, slightly

tapering, acute spinneret. Where the tail joins the spinneret the diameter is

about one-fifth as great as at the anus. There is a sudden and very slight

diminution of diameter of the terminus where it joins the spinneret. From

the inconspicuous vulva, the vagina leads inward and forward. The sym-

metrically reflexed ovaries reach about half way back to the vulva. The

thin-shelled, smooth eggs are relatively large and elongated and have

been seen in the uterus one at a time. They are about four to five

times as long as the body is wide and about one-fifth as wide as long.

They appear to be deposited before segmentation begins.

Habitat: Mud, Beach pool, Pine Point, Douglas Lake, Michigan.

Sublimate to balsam.

2. Rhabdolaimus minor, n.sp. .28 mm,

76 N. A. COBB

DIPLOGASTER, Max Schultz, 1857.

Fig. 3, Plate II.

MS CL IOF? (13S ela

3. Diplogaster fictor, Bustin acon ea 1.5 mm.

$:3 (ot bs Loar ae

The thin layers of the transparent, colorless, practically naked cuticle

are traversed by exceedingly fine transverse striae, resolvable with high

powers under favorable conditions, which become considerably coarser to-

ward the head, where they are resolvable into rows of refractive dots ar-

ranged in longitudinal, as well as transverse lines. A short distance behind

the head the longitudinal rows arrange themselves in pairs. These pairs

indicate the locus of about twenty-four cuticular ribs or wings, which extend

from the middle of the neck to near the anus. On the tail these ribs again

resolve themselves into double rows of dots, and gradually disappear as the

tail grows narrower. Very little is to be seen of them behind the middle

of the tail. The cylindroid neck ends in a somewhat rounded head, which

bears near its outer margin a circlet of six somewhat forward-pointing,

tapering cephalic setae, each about one-third as long as the head is wide.

There is one of these setae on each submedian line and one on each lateral

line. Just in front of the base of each lateral seta a minute obscure pore or

papilla was observed, which did not appear to exist in connection with the

other setae. The amphids, though only faintly visible, are of relatively

large size. Their form is partly indicated by a lateral area on which the

punctations of the cuticle are absent. This is a somewhat elliptical area

placed transversely on the side of the head, with its long axis at right angles

to the lateral line. Its length is equal to half that of the correspond-

ing diameter of the head. Its anterior contour is more definite than the

posterior, although it is only by the most caerful focusing that the defintie

line of contour can be distinguished. Through the middle of the area, how-

ever, there is quite a distinct arcuate line, with its convex side toward the

lips. When seen dorso-ventrally the amphids have the appearance of

distinct oblique openings, leading inward and backward. When the mouth

is opened and the lips recurved the amphids are moved forward somewhat

and the transverse line mentioned becomes more strongly curved and forms

a semi-circumference. The circular mouth opening is very finely striated on

the inner surface of the lip region. These striae begin on the inner face of

the lips near where the cuticular wall of the pharynx first appears. They

extend backward nearly to the base of the pharynx and end in-

definitely. In front of this finely longitudinally striated area the transverse

marginal portion of the lips is more coarsely divided into fourteen

parts. The lips are capable of being opened, so that the oral aperture

is two-thirds as wide as the head. Under such circumstances it is seen

that the lip region is flower-like in form with fourteen recurved seg-

ments, the distal tapering portion of each of which is plain and

FREE-LIVING FRESH-WATER NEMATODES 77

transparent, while the basal portion is traversed longitudinally by four min-

ute, refractive, somewhat beaded longitudinal striae. The pharynx is about

as deep as it is wide, and in its widest part is a little more than half as wide

as the front of the head. It is well filled at the base with the two cres-

cent-shaped, pointed, pharyngeal teeth. These extend inward and

then forward, their points being close to the body axis. The front contours

of the teeth are incurved, and at one point on their front surface they are

exceedingly finely striated. Each of these teeth occupies about one-fourth

of the width of the head; measured in the longitudinal direction its ex-

treme limits are less than when measured transversely. The entire length of

the pharynx is probably somewhat greater than the width of the head,

though it joins the lumen of the oesophagus in such an indefinite way

that it is sometimes rather difficult to say where the pharynx ceases and the

true oesophagus begins. The portion of the oesophagus surrounding the

pharynx is, however, distinctly, though slightly, swollen, so that it is proper

to speak of an elongated pharyngeal bulb. Just at the base of the phraynx

this bulb is two-thirds as wide as the corresponding portion of the head. At

a point two or three body diameters farther back it is only about half as

wide as the corresponding portion of the neck; thence onward it expands

a very little. Near the middle of the neck the oesophagus expands to form

the elongated muscular median bulb, which is three-fourths as wide as the

middle of the neck. Here the lining is more strongly developed, and occupies

about one-fourth of the optical longitudinal section, while the lining of the

preceding portion of the oesophagus occupies not more than one-fifth to one-

sixth of the diameter. Behind the median bulb the oesophagus is less strongly

developed. The lining is much less conspicuous and the radial muscular fibers

are less abundant. At first this posterior portion of the oesophagus is only

about one-fourth as wide as the middle of the neck. It expands gradually

until near the end, then more rapidly so as to form an elongated-

clavate swelling, three-fourths as wide as the base of the neck, The lining

of this portion of the oesophagus is a distinct feature, but is by no means so

strongly developed as that of the preceding portions of the eosophagus.

There is a well developed flattish cardia, half as wide as the base of the

neck. The intestine, which is separated from the oesophagus by a distinct

constriction, becomes at once about three-fourths as wide as the body. Its

cells contain scattered, nearly colorless granules of variable size, the largest

of which have a diameter nearly equal to the distance between two of the

adjacent longitudinal striations. From the slightly depressed anus the rec-

tum, which is about one and one-half times as long as the anal body diam-

eter, extends inward and forward. The tail is conoid from the anus and

tapers rather regularly to the extremely fine, hair-like terminus. There are

no caudal glands.

From the rather prominently elevated vulva the chitinized vagina leads

inward at right angles to the ventral surface half way across the body, where

it joins the two symmetrically-placed uteri. The reflexed ovaries reach

yin N. A. COBB

about half way back to the vulva and contain six to ten developing ova ar-

ranged single file. The thin-shelled eggs, which are deposited before

segmentation begins, are fully twice as long as the body is wide and

about one-third as wide as long, and occur in the uteri one at a time.

Full-grown ova are ellipsoidal, and about one and one-half times as long

as the body is wide and about half as wide as long.

“Oir12.3, 8155 -M 86.6

yy a Be Wa? a ee Bs 1.6

The tail of the male is like that of his mate in form. There are no sup-

plementary organs in front of the anus. The special male papillae charac-

teristic of this genus are located as follows: A single tapering, ventrally

submedian papilla a little in front of the proximal ends of the spicula, and

slightly farther back a lateral pre-anal papilla; a ventrally submedian papilla

as far behind the anus as that first described is in front of it; a lateral papilla

twice as far behind the anus as that just described; a ventrally submedian

papilla as far behind that just described as the latter is behind the previous

post-anal papilla; between the two ventrally submedian papillae just de-

scribed a group of minute subventral papillae; near the middle of the tail,

on the slender part, two sublateral papillae. Most of these papillae are

slender, tapering, and one-third to one-half as long as the anal body diame-

ter. The two equal, yellowish, arcuate, acute spicula are about one and one-

fourth times as long as the anal body diameter. They taper pretty regu-

_ larly from near the proximal ends, where they are one-fourth as wide as

the corresponding portion of the body. The proximal ends diminish sud-

denly in diameter, and are then cephalated by expansion. Each expansion is

« rather strongly refractive, more or less bulbous piece of chitin. The acces-

sory piece is arcuate and about one-third as long as the spicula. It is par-

allel to and applied closely to the spicula. Its framework consists of two

distinct, nearly parallel parts. The ejaculatory duct is about one-fourth as

wide as the body. The blind end of the single outstretched testicle lies a

little farther behind the base of the neck than this latter is behind the an-

terior extremity.

Habitat: Spring, Washington Country Club, Chevy Chase, Md.

Sublimate to balsam.

1.6 mm.

PRISMATOLAIMUS, de Man, 1880.

Fig. 4, Plate III.

6 ?

4. Prismatolaimus stenurus, n.sp. 12 7-4 22. 139" 04 I.I mm.

eS Ca OM Be

The moderately thin layers of the transparent, colorless cuticle are tra-

versed by about 550 transverse striae, resolvable with high powers into

rows of minute elements. There are no longitudinal striations. Scattered on

FREE-LIVING FRESH-WATER NEMATODES 79

the neck and body there are a few hairs arranged at right angles to the

surface. These generally have a length equal to the width of two to three

annules of the cuticle. The cylindroid neck ends in a somewhat truncated

head, which is not set off in any way. On the outer margin of the head at

the base of the lips there is a circlet of ten widely spreading, straight, taper-

ing cephalic setae, two of somewhat unequal size on each submedian line,

and one on each lateral line. The longest of these setae are a little more

than half as long as the head is wide. For two-thirds of their length they

are finger-shaped; the remaining third is a much narrower bristle. The

very thin lips are arched over the prismoid pharynx, which is nearly as deep

as the head is wide, and about three-fifths as wide as the head. It attains

its full width immediately behind the lips, and continues to have the same

width to the end, so that the bottom of the pharynx, though not even, ex-

tends across the base of the head approximately at right angles to the body

axis. Where the lumen of the oesophagus joins the pharynx there is, how-

ever, a slight backward extension of the pharyngeal cavity. There are no

eye-spots. The amphids occur in the form of somewhat elongated trans-

verse markings placed transversely on the neck somewhat farther behind

the base of the pharynx than this latter is behind the anterior extremity.

Each amphid has a length about one-third as great as the corresponding

width of the neck, and is about half as wide as long. Behind each amphid,

at a distance equal to the width of two to three annules of the cuticle, there

is a short seta. The oesophagus receives the base of the pharynx, and is

at once nearly three-fourths as wide as the head. It narrows very slightly

in diameter as it passes backward, so that where it passes through the nerve-

ring it is about two-thirds as wide as the neck. It continues to have prac-

tically the same diameter to near the end, where it is two-thirds as wide as

the base of the neck. Immediately in front of the intestine there is a small

segment of the oesophagus which is set off by a constriction. This

portion is somewhat spheroidal in form. The lining of the oesophagus is a

distinct feature throughout its length, and comes into view in the optical

section as a single refractive line. This line is nowhere materially altered.

There is no distinct cardia, unless the above mentioned spheroidal segment

of the oesophagus may be so considered. The rather thick walled intestine,

which is set off from the oesophagus by a distinct constriction, becomes at

once about two-thirds as wide as the body, and is composed of cells of such

a size that probably about four are required to build a circumference. These

cells contain numerous granules of rather uniform size, which are not dis-

posed so as to give rise to a tessellation. From the somewhat continuous

anus the rectum, which is about as long as the anal body diameter, extends

inward and forward. The tail end begins to taper from some distance in

front of the anus, and tapers regularly thereafter throughout the anterior

portion of the tail. The posterior portion tapers very slightly, and has a

diameter one to two times as great as the width of one of the annules of

the cuticle, measured near the anus. Though the terminus has considerable

80 N. A. COBB

width there is no spinneret. The lateral fields are about one-third as wide

as the body. The nerve-ring surrounds the oesophagus somewhat squarely.

On the dorsal side, a little behind the cardiac constriction there is a body

which presses the intestine a little to one side, which may perhaps be the

renette cell. This body has a length as great as the corresponding body di-

ameter, and is about one-fourth to one-third as wide as long. The vulva is

somewhat elevated, and from it the vagina extends inward at right angles to

the ventral surface about one-third the distance across the body. There are

two symmetrically disposed, reflexed ovaries, the blind ends of which lie

near the vulva, the position depending to a considerable extent upon the de-

velopment of the much elongated eggs. The ovaries are moved backward

and forward to a certain extent in accordance with the stage of develop-

ment of the eggs. The eggs, which have been seen in the uteri one at a time,

are much elongated—four or five times as long as the body is wide—

and about one-fifth as wide as long. They appear to be deposited before

segmentation begins.

Habitat: Roadside pool, Douglas Lake, Michigan. Sublimate to

balsam.

SPILOPHORA, Bastian, 1865.

Fig. 5, Plate III.

5. Spilophora canadensis, n.sp.

The thin, transparent layers of the colorless, practically naked cuticle

are traversed by 750 transverse striae, resolvable with high powers into

rows of dots, which at the lateral wings are so modified as to give rise to

two distinct longitudinal rows of dots of larger size. Along the middle of

the body one of these rows is more pronounced than the other. Opposite

the base of the neck the distance between these two longitudinal rows is

about four times as great as the distance between two of the dot-like ele-

ments. There are no eye-spots, nor have any distinct traces of amphids been

seen. If the latter are present they must be very inconspicuous. The lips are

so small that it is very difficult to count them, but there appear to be twelve,

each one obscurely conical. There are no very marked subdivisions between

these lips, so that the shallow cyathiform anterior portion of the pharynx,

(a, Fig. 5) which is about half as wide as the head and about one-third to

one-half as deep as wide, is not prominently striated radially as is some-

times the case in this and related genera. From the slightly depressed vulva,

the vagina leads inward at right angles to the ventral surface about half way

across the body, where it joins the two symmetrically-placed uteri. The re-

flexed ovaries reach fully half way back to the vulva, at least in young speci-

mens such as have been examined, and contain a dozen to twenty developing

ova arranged in more or less double file. The eggs appear to be elongated,

somewhat longer than the body is wide and about one-third as wide as long.

It is possible, however, that there 1s some error here as the description is

FREE-LIVING FRESH-WATER NEMATODES 81

derived from a single specimen in which these features are rather obscure.

The reversal in the striations of the cuticle is plainly to be seen in the re-

gion of the vulva, and its location is indicated by a slight rise in the contour.

This slight elevation extends also to the subcuticle.

5 83 148 -M 884

AY Sy by St 5a

The wing markings on the anterior part of the tail are pronounced,

but on the posterior part much less so. A little in front of the

anus they are as pronounced as they are at the base of the

neck, and both are equally visible, and the structure not infrequently re-

sembles that of a ladder with the rungs placed close together, just as it does

on the neck. The lateral fields appear to be about one-third as wide as the

body. Near the middle of the body may plainly be seen the location where

the cuticle reverses its structure. Although the striations are minute they

present the same character as in species where the striations are coarse, and,

upon careful examination, can be seen to be retrorse in opposite directions

on the two halves of the body.

Habitat: Fresh water ponds, Cape Breton Island, Dominion of Canada.

7 mm,

MICROLAIMUS, de Man, 1880.

Fig. 6, Plate IIT.

6. Microlaimus fluviatilis, n.sp. PE PSS ISSA PS mm.

190° 3.5 43. 47> 126

The thin layers of the transparent, colorless, naked cuticle are traversed

by exceedingly fine transverse striae, which are resolvable with great diffi-

culty into rows of dots, and are not modified on the lateral fields. The

conoid neck ends in a rounded head set off by an almost imperceptible con-

striction. On the outer margin of the head there is a circlet of four sub-

median, slightly tapering cephalic setae, each about one-third as long as the

head is wide. The vestibule is considerably shorter than any of the cephalic

setae, and is longitudinally striated, indicating, no doubt, that the lips can

be opened outward in receiving food. These longitudinal striations of the

vestibule are too minute to be counted, but there are apparently about twelve.

The circular amphids are about one-fourth as wide as the corresponding

portion of the head, and are located at a distance from the anterior ex-

tremity equal to one and one-half times the diameter of the front of the

head. There are no eye-spots. The limits of the pharynx are indicated by

a slight constriction in the oesophagus. The base of the pharynx is some-

what more than halfway back to the amphids. The general form of the

pharynx is cylindroid or prismoid. It is armed with minute and very in-

conspicuous, somewhat inward pointing and apparently not very regular

teeth or projections. The most conspicuous of these projections are two just

behind the base of the lips, one dorsal and the other apparently ventral, and

82 N. A. COBB

a third at the base of the pharynx on the dorsal side. The oesophagus be-

gins as a tube about half as wide as the corresponding portion of the neck,

and continues to have this diameter until it swells to form the pyriform

cardiac bulb, which is about three-fourths as wide as the base of the neck,

and contains a distinct chitinized threefold, rather simple, valvular apparatus,

occupying two-fifths of the diameter as seen in longitudinal section. The

musculature of the bulb is divided into three sections, a small anterior sec-

tion, a middle and a posterior section. Of these two latter the posterior is

slightly the smaller. The lining of the oesophagus is a fairly distinct feature

throughout its length. There is no very distinct cardia. The intestine joins

the middle of the posterior surface of the cardiac bulb, and is there one-

fourth as wide as the base of the neck. It soon expands so as to become

about two-thirds as wide as the body. It is rather thick walled, and is com-

posed of rather thick cells which are of such a size that about four are re-

quired to build a circumference. These cells contain minute granules. From

the anus the rectum, which is considerably longer than the anal body diam-

eter, extends inward and forward. The tail is conoid, and tapers from the

anus toward the terminus, which is conoid and has a diameter one-third as

great as that of the base of the tail, and bears a blunt convex-conoid unarmed

spinneret. The rather small caudal glands appear to be located in the an-

terior third of the tail. The lateral fields have not been seen. From the

inconspicuous vulva the vagina leads inward at right angles to the ventral

surface to the single or double uterus, which when single extends forward.

There sometimes appears to be a small posterior rudimentary branch to the

sexual organs, which is about equal in length to the corresponding body

diameter. The reflexed ovary reaches about halfway back to the vulva,

and contains about half a dozen or more ova arranged somewhat irregu-

larly. The eggs appear in the uterus one at a time. They are smooth, some-

what thin-shelled, and are about twice as long as the body is wide, and about

one-third as wide as long. They appear to be deposited before segmentation

begins. Specimens with one ovary, and those with two, appear to be about

equally numerous; as no other difference has been detected, they are in-

cluded for the present under the same name and description. The renette

cell is an elongated cell located a short distance behind the base of the neck.

It is fully as long as the body is wide, and about one-fourth as wide as the

body. The excretory pore appears to be located opposite the nerve-ring.

The nerve-ring surrounds the oesophagus somewhat squarely.

Habitat: Maple River, Michigan. Sublimate to balsam.

TRIPYLA, Bastian, 1865.

Fig. 7, Plate ITI.

~ : 1.1 68 19.6 ‘54’ 83.

7. Tripyla lata, n.sp. emg ne ESA 2.4 mm.

7 RG OR ae. s\2

The thick layers of the transparent, colorless, naked cuticle are apparently

traversed by about 250 transverse striae, which are not further re-

FREE-LIVING FRESH-WATER NEMATODES 83

solvable. In the lumen of the pharynx at a point removed from the

anterior extremity a distance a little greater than the radius of the

head, there is a minute inward-pointing dorsal tooth, having a length

about equal to the width of one of the annules of the cuticle. This

and other matters prove that the pharynx, although not readily dis-

tinguished, extends backward a distance about equal to the width of

the head. In some specimens it is possible to see a distinct transverse

fold in the lining of the oesophageal tube. This is located at a dis-

tance from the anterior extremity about equal to the corresponding

diameter of the head, and undoubtedly indicates the posterior lim-

its of the pharynx. It is possible that the tooth just mentioned may be con-

nected with internal glandular structures in the oesophagus, as the interior

of the dorsal segment of the oesophagus at this point is usually more or

less different in structure from the other portions and does not seem to be

made up entirely of muscular fibers. The oesophagus is separated from the

intestine by a flattish, pseudo-bulb. The bulb is separated from the oesopha-

gus on one side and the intestine on the other by deep and distinct constric-

tions. In the anterior constriction there are at least two granular, elongated

cells of considerable size. The nerve-ring surrounds the oesophagus rather

squarely. Nothing definite is known concerning the renette or the excretory

pore. From the inconspicuous vulva, the vagina leads inward at right

angles to the ventral surface fully half way across the body, where it joins

the two symmetrically-placed uteri. The reflexed ovaries reach about half

way back to the vulva, and contain a dozen to twenty developing ova ar-

ranged somewhat irregularly. Both in front of and behind the vulva there

are unicellular glands, having a diameter about one-sixth as great as that

of the body.

7 68 19.3 -M- 8&8

Ss 2.4 mm.

ait ‘at ts oe a8 4.1 RS

The tail of the male is like that of the female except that the anus

is slightly raised. In front of the anus there is a ventral row of about

twenty innervated supplementary organs, reaching to near the head.

The distance between two consecutive organs is about equal to the ra-

dius of the body. Each of these appears to consist of a nerve-ending

which penetrates the cuticle and forms a papilla, around which there is

an almost imperceptible elevation having a width about equal to two of

the annules of the cuticle. The visibility of this small organ is quite as

much due to the alteration in the body wall and subcuticle as to that in

the cuticle. There are no supplementary setae or papillae either in

front of the anus or behind it. The two equal, slightly arcuate, uni-

formly tapering, acute spicula are about one and one-fourth times as

long as the anal body diameter. Their proximal ends are not cephal-

ated, though the wall of the cuticle is very slightly thickened at that

point. The spicula taper regularly from the proximal ends to the rather

84 N. A. COBB

truncated points. There are obscure accessory pieces lying close to the

surface of the spicula and forming a double groove in which these lat-

ter slide. The ejaculatory duct, though narrow at first, soon becomes

nearly half as wide as the body. There are two slender, outstretched

testicles extending in opposite directions from near the middle of the

body. The anterior one has its blind end about as far behind the base

of the neck as the nerve-ring is in front of it.

Habitat: Alpine lakes, Bald Mountain, Colorado. Formalin to glycerine.

TERATOCEPHALUS, de Man, 1876.

Fig. 8, Plate IV.

> 84.

LY >) £0) 2040 Vie

The thin, transparent layers of the colorless naked cuticle are traversed

by about 1500 transverse striae, resolvable into rows of minute dots, which

are modified on the lateral fields. These modifications have been seen in

all parts of the body, and near the tail consist of two to three irregular

longitudinal rows of enlarged dots. The posterior portion of the neck ta-

pers but little. The anterior portion becomes convex-conoid toward the head,

which bears a lip region more or less set off by a constriction opposite the

base of the spreading cephalic setae, which are four in number and

submedian in position. Each seta is a little more than half as long as the

head. These are connected with a refractive six-ribbed chitinous dome-like

framework, which extends back to opposite the middle of the pharynx. The

ribs start at the lip region, extend backward, and then join each other oppo-

site the base of the vestibule. The chitinous refractive elements at this latter

region form a rather distinctly crenate contour around the head. No

other setae than the cephalic setae have been seen in any part of the body.

The lips appear to be rather thin, and are arched together over the

unarmed pharynx, which is somewhat elongated and about half as wide

as the base of the head. While it is somewhat irregular in form it

is approximately prismoidal or cylindroid and nearly as deep as the

head is wide. Its walls are not very strongly chitinized, but more

strongly so anteriorly than posteriorly. The oesophagus receives the

base of the pharynx, and soon becomes half as wide as the, base

of the head. In the anterior portion of the oesophagus, a short distance

behind the pharynx are three slightly arcuate, refractive elements, corre-

sponding somewhat in. curvature with the contour of the front end

of the oesophagus. These resemble to a certain extent the refractive ele-

ments in the posterior chamber of the pharynx of Plectus. In the present

species they are about as long as the pharynx, and are separated a dis-

tance about equal to one body width. They are a little wider and more

plainly visible anteriorly than posteriorly. The obscure amphids, as

ly aia? 2 Ee Shrek 4s *

8. Teratocephalus cornutus, n.sp. .& mm.

FREE-LIVING FRESH-WATER NEMATODES 85

far behind the base of the pharynx as this latter is behind the anterior

extremity, are one third as wide as the corresponding part of the head.

and consist of obscure spirals of one wind. There are no eye-spots.

The oesophagus begins as a tube about half as wide as the correspond-

ing portion of the head, but expands very slightly as it passes back-

ward, so that at the middle it is about two-thirds as wide as the

middle of the neck. Behind this point it diminishes. There is a

break in the musculature somewhat similar to that occurring in Cephalobus.

At the break, which occurs at the beginning of the fourth fifth, the

oesophagus is somewhat narrow, about half as wide as the corre-

sponding portion of the neck. It finally expands to form the ellipsoidal

cardiac bulb, which has a relatively large, chitinous, striated, complicated,

three-fold valvular apparatus half as wide as itself. There is a truncate-

conoid cardia about one-third as wide as the base of the neck. The lining

of the oesophagus is a fairly distinct feature. The thick-walled intestine,

which is separated from the oesophagus by a constriction, soon becomes two-

thirds as wide as the body. It is composed of cells of such a size that four

are required to build a circumference. The walls of these cells are refrac-

tive, so that the cells are readily distinguished from each other, though there

is no distinct tessellation. These cells contain minute very uniform granules.

The lining of the intestine is refractive, so that the lumen is distinctly to be

seen. From the rather inconspicuous anus the rectum, which is about as

long as the anal body diameter, extends inward and forward. The internal

sexual organs are double and symmetrically reflexed. The tail is conoid

from the anus to the subacute terminus. This species is related to those

described by Dr. de Man under the name of Teratocephalus. It is doubtful

whether these forms will not have to be subdivided at some future time,

after the accumulation of the necessary data.

Habitat: Maple River, Michigan. Sublimate to balsam.

ALAIMUS, de Man, 1880.

Fig. 9, Plate IV.

9. Alaimus simplex, n.sp. | adele NGN Leta! 2. mm.

E CS Para eyo & eBeey «

The thin, transparent layers of the colorless, naked cuticle would ordi-

narily be described as destitute of striations. Very minute striations may

be observed in the subcuticle at the extremities, when the specimens are ex-

amined under favorable conditions with the highest powers. There are

obscure traces of lateral wings. The conoid neck ends in a rounded head

not set off in any way. There are no distinct lips, and only the faintest

possible indications of labial papillae. These are so obscure that it has been

found impossible to enumerate them. There is no pharynx and the mouth

opening is exceedingly minute. No amphids or eye-spots have been seen.

86 N. A. COBB

The oesophagus begins at the lip region as a tube two-thirds as wide as the

head, and expands gradually and rather regularly to the end, where it has

a diameter three-fourths as great as that of the neck. A short distance be-

hind the head end, a distance six ‘times as great as the diameter of the head,

there is a slight alteration in the structure of the oesophagus the significance

of which remains doubtful. The lining of the oesohpagus is not a very dis-

tinct feature. There is a very obscure, small cardia. The intestine, which

is separated from the oesophagus by a constriction, becomes at once about

two-thirds to three-fourths as wide as the body. At first its cells contain

but few scattered granules, but soon they are characterized by the presence

in them of loosely scattered yellowish-brown granules of variable size, the

largest of which have a diameter nearly one-eighth as great as that of the

body itself, and the smallest of which are very much smaller. These are

not arranged so as to give rise to any distinct tessellation. Toward the end

of the intestine the granules again become less abundant and smaller, so

that for some distance in front of the rectum there is only here and there

a granule. From the depressed and conspicuous anus the chitinized rec-

tum, which is a little longer than the anal body diameter, extends inward

and forward. There is no distinct pre-rectum. The tail end begins to taper

from a long distance in front of the anus, but tapers very gradually to

behind the anus. Thence onward it is inclined to be arcuate and tapers

regularly to near the terminus. Near the end it tapers more rapidly than

elsewhere, and finally comes to an almost acute point at the terminus. A

short distance in front of the terminus, however, the diameter is about half

as great as it is at the anus. There does not appear to be any spinneret, and

therefore, of course, caudal glands are absent. The lateral fields appear to

be about one-third as wide as the body. Nothing is known concerning the

excretory pore. From the slightly elevated vulva the vagina leads inward

nearly at right angles to the surface more than halfway across the body,

where it joins the single uterus, which extends backward. The ovary is

reflexed, and the blind end is about halfway back to the vulva. The eggs

occur in the uterus one or two at a time, and are very much elongated. They

are about six times as long as the body is wide, and about one-eighth as wide

as long, and are covered by a distinct, smooth shell. They are apparently

deposited before segmentation begins. The spermatozoa appear to be elon-

gated-ellipsoidal, and a little more pointed at one end than at the other. They

have a length one-fifth that of the body diameter.

2 74 15. M_ 94.

Bla 7. OA

The tail of the male is like that of the female in form and size, but

the anus is somewhat elevated. In front of the anus there appears to be a

ventral row of very obscure, broad, flattish supplementary organs. Perhaps

these ought to be described as locations of nerve endings rather than

as distinct organs. Their number remains doubtful, but there are about

FREE-LIVING FRESH-WATER NEMATODES 87

three or four occupying a distance equal to half the length of the tail.

The two equal, straight spicula are rather obscure. Their length is no

greater than the length of the anal body diameter. Oblique copulatory

muscles are seen in the vicinity of the spicula, and there is a refrac-

tive element passing backward from the accessory piece toward the

ventral side of the tail near the anus, which may be muscular, or

possibly chitinous and serving for the attachment of muscles. The

ejaculatory duct is about one-third as wide as the body, the vas def-

erens somewhat wider. Whether there are two testes or only one has

not been determined. There is a _ broad, rounded, blunt end of a

testis located as far behind the base of the neck as this latter is behind

the anterior extremity.

Habitat: Big Lake, Fla. Bouin solution to glycerine.

PLECTUS, Bastian, 1865.

Fig. 10, Plate IV.

j 2 TOPE IO, OA Oa

10. Plectus tubifer, n.sp. cat dtearel deca Chi 2S ira 74 mim.

ota AS Oe Aa Ee ede te,

The skin is of medium thickness, colorless, and traversed transversely

by fine, plain striae. The striae are of such a size that about twenty of them

occupy a space equivalent to the body diameter. There are no hairs on the

surface of the body, but throughout the length of the body, more particularly

on the submedian lines, may be seen very faint markings in the cuticle, which

indicate the location of four rows of pores connecting with interior organs.

Immediately behind the lateral organs one sees the first of the series of pores

located in the lateral line. This first pore, though much smaller than the

lateral organs, is yet somewhat larger than the succeeding ones, which grad-

ually spread out to form two submedian rows. The total number of these

pores on one side (of the male) is about one hundred; that is, there are about

two hundred in all. The six low, rounded lips are rather massive, and are

arched together over the pharynx. These lips appear to be armed with

chitinous processes on the inner surface, these processes surrounding a short

_ napiform vestibule leading to the pharynx proper. If any labial papillae are

present they are exceedingly minute; what appear to be traces of papillae

may occasionally be seen. The lateral organs are well forward, being lo-

cated only slightly behind the cephalic setae. They present transversely

elongated contour markings open on the posterior margin. The lateral fields

appéar to attain a considerable width and two chitinous, lateral markings

close together with a third between them, appear to indicate the existence of

a wing on each side of the body.

88 N. A. COBB

19 I01 19.2 ‘-M 91.5

CASA EELE Ge RE eC Le rs 1s 8

2) BOE ONS A 9.04 S33

2A TOS IO. Gone OS.

TO 2 ee 2 aa eT aes

possessed four supplementary organs, the additional one being some little

distance in front of the others, which were arranged as_ illustrated.

Sometimes there are only two of these organs, one smaller than the other.

The cuticle of the ventral surface is slightly thickened and elevated where

it is pierced by these tubular organs, which appear in some instances to be

slightly exserted. Apart from these preanal supplementary organs, there

are ventrally submedian papillae on the tail;—one pair near the middle, an-

other pair half way between these and the anus, and a third pair part way

from that first mentioned to the terminus. There is a fourth pair indistinctly

to be seen just behind the anus; these are closer together than the members

of the other pairs. Furthermore there are one or two very small pairs near

the terminus, but perhaps these may partake more of the nature of hairs

than of papillae. Just in front of the anus there is a single ventral almost

setose papilla. There occur in front of the anus at least two pairs of ven-

trally submedian papillae. These are located one just in front of the pos-

terior supplementary organ and the other just behind it. Most of these

features are not easy to decipher, very careful observation being necessary to

enumerate the papillae as above. There are two testicles, one anterior to

the other, the anterior being outstretched and extending forward, the pos-

terior being reflexed near its middle, so that its blind end lies somewhere

near the junction of the two. The anterior one of this pair is connected

with the seminal vesicle by a tubular portion, which lies alongside the re-

flexed posterior member.

Habitat: Arlington, Va. Flemming solution to glycerine.

One male whose formula was .Q mm.

DORYLAIMUS, Dujardin, 1845.

Fig. 12, Plate V.

4.4 16. ‘43’ 96.

ATT EULON AO Te

The thin layers of the transparent, colorless, naked cuticle are traversed

by exceedingly fine, plain, transverse striations resolvable with the highest

powers of the microscope under favorable conditions. Longitudinal striations

are visible throughout the length of the body. The presence of amphids is

indicated by a transverse marking immediately behind the lip region, and

somewhat in front of the guiding ring of the spear. The anterior contour

of each organ is a transverse line about three-fifths as long as the corre-

sponding portion of the head is wide. Extending backward from this are

lateral contours which approach each other slightly and end indefinitely. The

11. Dorylaimus fecundus, n.sp. 3.4 mm.

FREE-LIVING FRESH-WATER NEMATODES 89

oesophagus begins as a tube about half as wide as the corresponding portion

of the neck, and continues to have this diameter until near the middle of

the neck, where it first begins to expand. A little behind the middle of the

neck it expands rather suddenly, so that the remainder of the organ is about

two-thirds as wide as the base of the neck. There is a much elongated

conoid cardia nearly as long as the body is wide. The intestine, which be-

comes at once three-fourths as wide as the body, is separated from the

oesophagus by a distinct though slight constriction. The cells forming the

intestine are of such a size that about four or five are required to build a

circumference. They contain granules of variable size, the larger of which

have a diameter equal to the thickness of the outer transparent cuticle, and

the smaller a diameter only about one-fourth as great as that of the larger.

These granules are so arranged as to give rise to a very obscure tesselation.

The pre-rectum is about three to four times as long as the corresponding

body diameter, and is separated from the intestine by a difference in struc-

ture, the granules contained in its cells being smaller, and not darkening un-

der the influence of osmic acid, as do those of the intestine. Nothing is

known concerning the salivary glands or the renette. The longitudinal fields

are well developed, being about half as wide as the body. The nerve-ring-

surrounds the oesophagus somewhat obliquely. Each of the two elongated

uteri may contain three to five eggs at a time. These, as they appear in the

uteri, are elongated, finely granular, rather thin-shelled, and about one and

one-half times as long as the body is wide, and about half as wide as long.

The shells are flexible, so that owing to the pressure of one egg on another

in the uterus the surfaces are often indented.

3 48 17. -M-— 99.

OSs te Latte A 1.4

In addition to the ventral row of supplementary male organs shown in

the illustration, there are two rows of ventrally submedian, innervated papil-

Jae, arranged in a somewhat equidistant manner. Where these reach the

surface of the body they give rise to almost imperceptible elevations which,

however, are of a different character from those at the ends of the ventral

organ shown in p, Fig. 12. In other words, these papillae are more nearly the

homologues of the ordinary tactile hairs or papillae so common on the sur-

face of nematode worms. These submedian papillae are located at a

distance from each other equal to about two-thirds the body diameter.

They are very nearly coextensive with the oblique copulatory muscles.

Habitat: Algae, Potomac River, Washington, D. C., 1911. Flem-

ming solution to glycerine.

3.5 mm.

go N. A. COBB

IRONUS, Bastian, 1865.

Fig. 13, Plate V.

. ; 3.97- (O20 ee hes

12. Ironus americanus, n.sp. $+ __—_—___—_—_—§|—— 2.3 mm.

160° 42350 275 2048s

The moderately thin layers of the transparent, colorless, naked cuticle

appear to be destitute of striations. There are three somewhat conoid lips,

which when open, give to the head a somewhat truncated appearance, when

folded a somewhat rounded appearance. Each lip bears internally a slightly

arcuate, conical tooth, whose altitude is somewhat greater than the width

of its base. When the mouth is so opened that the apices of these refractive

teeth are about on a level with the anterior extremity their bases lie a little

in front of the bases of the cephalic setae. The apices of these teeth are

slightly blunt and they have a slight outward curvature. The walls of the

pharynx are strongly refractive, and have about the same thickness as the

walls of the cuticle. The chitin of the walls of the pharynx, however, is

more refractive than that of the cuticle. In this respect it resembles the

chitin of which the teeth are composed. Except for the teeth at the mouth

opening the pharynx is unarmed, but presents on the dorsal side about half

way between the head and its posterior extremity three or four exceedingly

minute projections with corresponding depressions. The oesophagus begins

near the base of the pharynx, at least it is at this point that the radial struc-

ture becomes pronounced. At first it is about two-thirds as wide as the cor-

responding portion of the neck. It enlarges a little and very gradually, so that

finally it is about half as wide as the base of the neck. The lining of the

oesophagus is an exceedingly distinct feature throughout its length. It gen-

erally has the appearance of three refractive lines occupying a space nearly

one-fourth as wide as the oesophagus itself. There is a large cylindroid

or hemispherical cardia, one-third as wide as the base of the neck. The in-

testine, which is separated from the oesophagus by a deep, narrow and dis-

tinct constriction, becomes at once about three-fifths as wide as the body.

Its cells contain scattered granules of variable size, the largest of which have

a diameter nearly equal to the width of the refractive portion of the lining of

the oesophagus, and the smallest of which have a diameter not more than

one-tenth as great. The body wall is thick, generally occupying about three-

fifths of the diameter of the body. The lateral fields are a little more than

one-third as wide as the body. Nothing is known concerning the renette

or the excretory pore. There is no spinneret. The tail, nevertheless, con-

tains small cells near the anus which bear a certain resemblance to the ordi-

nary caudal glands. From the slightly elevated vulva, the vagina leads in-

ward at right angles to the ventral surface half way across the body where

it joins the two symmetrically-placed uteri. The reflexed ovaries reach

three-fourths the distance back to the vulva, at least in specimens which do

not contain eggs. The ovaries contain about a dozen ova arranged for the

FREE-LIVING FRESH-WATER NEMATODES gi

most part single file. Nothing very definite is known concerning the form

and size of the eggs, but from the size of the apparently matured ova it is

assumed that the eggs are considerably elongated, perhaps two to two and

one-half times as long as the body is wide, and if so, it is unlikely that

more than one is contained in the uterus at-a time.

Habitat: Deer Bottom, Pikes Peak region, Colorado. Formalin to

glycerine.

ONCHOLAIMUS, Dujardin, 1845.

Fig. 14, Plate V.

13. Oncholaimus punctatus, n.sp.

The rather thin, transparent, colorless layers of the naked cuticle appear

to be destitute of striations. It is rather difficult to observe the cuticle on

account of the presence in it of numerous dot-like elements, which near the

head are arranged in longitudinal groups, of which the widest is the lateral

group. The longitudinal arrangement of the granules, is continuous through-

out the body, but it is most marked on the lateral fields where there is a

definite band of them, having a width about two-fifths as great as the width

of the body. Each margin of this band is made up of a distinct longitudinal

row of granules arranged single file. The neck is slightly conoid, becoming

slightly convex-conoid toward the rounded head, which is not set off in any

way, or at most by an exceedingly obscure, broad constriction opposite the

pharynx. The six lips are distinct and well developed and have a distinct,

somewhat chitinous framework. They are arched together over the pharynx

in such a way as to produce a dome-like effect, the very thin and movable

flaps at the ends of the lips meeting together at the middle of the front of

the head. Opposite the middle of the amphids there is a transverse marking

or line which extends around the middle of the head. It is characterized by

staining somewhat more strongly with carmine than the other portions of

the cuticle. There are no eye-spots. The oesophagus begins at the base of

the pharynx with a diameter three-fourths as great as that of the base of the

head, and it continues to have this diameter until some distance behind the

nerve-ring. It then begins to expand gradually, so that finally it is about

three-fourths to four-fifths as wide as the base of the neck. The lining is a

distinct feature throughout the length of the oesophagus. There is a dis-

tinct conoid cardia, whose base is about half as wide as the corresponding

portion of the body. The intestine, which is separated from the oesophagus

by a deep and distinct constriction, appears to have rather thin walls and to

be composed of cells of such a size that probably six or more would be re-

quired to build a circumference. These cells contain numerous granules of

rather uniform size.

The lateral fields are about two-fifths as wide as the body. The loca-

tion of the ventral gland has not been made out. The excretory pore is lo-

92 N. A. COBB

cated just behind the base of the pharynx. The duct which leads to it seems

to be destitute of an ampulla.

1.9 102 21.4 —M-— 92.

Bio hokey awe 2.1 mm.

T2122} ores 1.8

In front of the anus there is a series of about fifty pairs of oblique

copulatory muscles, whose presence is indicated by the oblique groups of

granules in the cuticle. The ejaculatory duct is about one-third as wide as

the body. The blind end of the anterior testicle is about twice as far behind

the base of the neck as this latter is behind the anterior extremity.

Habitat: Fresh water ponds, Cape Breton Island, Dominion of Canada.

Sublimate to balsam.

DOLICHODORUS, nig.

Fig. 16, Plate VI.

14. Dolichodorus heterocephalus, fig to oS Zit 1d ae ORS mm.

6) UOag eas ae

The thin layers of the transparent, naked, colorless cuticle are traversed

by transverse striae resolvable with high powers under favorable conditions

into rows of exceedingly minute, somewhat irregular elements. This reso-

lution is not at all difficult in specimens which are moulting. Under these

conditions scales of the outer cuticle sometimes survive, readily resolvable

into refractive transverse markings between which are the small elements

mentioned. Ordinarily at first glance, the cuticle appears to be merely re-

solvable into transverse striae which are somewhat roughened on the edges

of the dividing lines. The conoid neck ends in a head which has a very

prominent lip-region set off by a very prominent and deep constriction. The

front of the head is rounded, and the constriction separating the lip-region

from the remainder of the head is of such a nature that the contour of the

lip-region, when seen in optical longitudinal section is somewhat elliptical, so

that the lip-region has the form of an ellipsoid of rotation. The depth of

this figure is about equal to half its width. No papillae have been seen on

the lips, but minute papillae might readily be present without having been

observed. No traces of amphids have been seen. There are no eye-spots.

The vestibule is exceedingly narrow and closely surrounds the apex of the

very slender narrow spear. This latter extends nearly half-way to the an-

terior border of the median bulb and is long and slender like that of

Trichodorus. The oesophagus at the base of the spear is a tube about one-

third as wide as the corresponding portion of the neck, and continues to have

this diameter until it expands suddenly to form the elongated median bulb,

which is three-fourths as wide as the corresponding portion of the neck and

fully twice as long as wide and is armed internally with a conspicuous, ellip-

soidal, rather simple valvular apparatus nearly half as wide as itself. When

FREE-LIVING FRESH-WATER NEMATODES 93

seen in optical longitudinal section the bulb is a little wider posteriorly than

anteriorly, so that its sides are not parallel, but approach each other a trifle

as they pass forward. The bulb ends more abruptly posteriorly than an-

teriorly, and is continued by a narrow section of the oesophagus only one-

eighth as wide as the corresponding portion of the neck and about as long

as the corresponding portion of the neck is wide. This is succeeded by a

broadly clavate swelling which does not have any distinct chitinous lining,

and is of granular structure, rather than muscular. This swelling is about

two-thirds as wide as the base of the neck. The lining of the oesophagus

is a fairly distinct feature in all parts in front of the posterior swelling.

The intestine joins the middle of the rounded surface of the posterior oeso-

phageal swelling and is at this point only one-tenth to one-eighth as wide

as the corresponding portion of the body, but soon expands to be two-fifths

as wide as the body. It is, therefore, relatively narrow. On the other hand,

the body walls are correspondingly thick. Nothing is known concerning

the renette cell. It is probable that there is an excretory pore located near

the nerve-ring.

3 (2.3) 79 109 -M = 993

2.4 mm.

AUC gas) Lies Tia ts Be 1.8 rene

The tail of the male is conoid and extends beyond the anus a distance

hardly as great as the length of the anal body diameter. It seems likely that

the tail is also flattish. When seen dorso-ventrally it appears to be about one-

half as long as the spicula, and ends in a dentate terminus one-third as

wide as the base of the tail. The cuticle of the tail is very thick, and at

first sight seems rather closely to resemble the structure of the two bursal

flaps. The distinctly two-parted bursa springs from opposite the middle of

the spicula and extends backward and is completely furcated at a point

about opposite the base of the tail. The flaps extend backward beyond the

terminus of the tail and give to the posterior extremity somewhat the appear-

ance of ending in three thin transparent, colorless flaps, one of which is

soon seen to be the true caudal extension. The flaps of the bursa are striated

in much the same manner as the cuticle, and the margins of the flaps are

distinctly thickened. No distinct ribs have been seen in the two broad

backward pointing flaps of the bursa. The two equal, rather strongly built,

tapering spicula have a length about one and one-half times as great as that

of the diameter measured opposite their proximal ends. They are accom-

panied by a rather simple accessory piece one-half as long as themselves,

judging from its appearance when seen dorso-ventrally. The proximal ends

of the spicula can hardly be said to be cephalated, but they are obliquely

trancated and wider than elsewhere. When seen dorso-ventrally this width

appears to be one-fourth as great as that of the corresponding portion of

the body. No special setae are present and no special papillae have been

seen. The single outstretched testicle extends forward and has its blind

end located about three to four times as far behind the base of the neck

04 N. A. COBB

as this latter is behind the anterior extremity. Near its blind end its diam-

eter is about one-half as great as that of the body. The spermatozoa are

small and numerous and it appears that the reduction divisions take place in

a short segment of the testis not far from the blind end.

Habitat: Freshwater, “Douglas Lake,” Michigan. Silver Spring,

Florida. Female, Flemming solution to glycerine; from Florida. Male,

from Michigan, sublimate to balsam.

CYATHOLAIMUS, Bastian, 1865.

Fig. 17, Plate VI.

20.

5 hee At Gk. Ailes 2 88.

1.6 mm.

16. 2. Pode ES Ee 2.1

The moderately thick layers of the transparent, colorless, naked cuticle

are traversed by about fifteen hundred transverse striae, resolvable into

transverse rows of distinct dots, which are not very materially modified in

the lateral fields. The slightly conoid neck ends in a truncated head, whose

lip region is set off by an almost imperceptible expansion. The cuticle be-

comes somewhat thicker toward the head, and the dotlike markings more

distinct and refractive. Beginning near the head and ending near the spin-

neret there are circular markings arranged in somewhat irregular rows

along the lateral fields. The longitudinal distance between these markings

near the middle of the body is a little greater than the radius of the body,

and the diameter of the circles is somewhat greater than the width of one

of the annules, sometimes twice as great. These markings are not all of the

same size, some being nearly twice as large as others.* The lip region is

twelve-parted, and there are twelve longitudinal chitinous structures sur-

rounding the vestibule. These no doubt indicate the infolding of the lips

when closed. Probably the best conception of the lip region is expressed by

saying that there are six lips, each two-parted, but that the divisions are all

15. Cyatholaimus truncatus, n.sp.

very similar to each other. On the front of the lips there are six forward _

pointing innervated papillae arranged in the usual position. Along the outer

margin of the head there are ten acute, tapering, cephalic setae, two lateral,

and four submedian pairs. The longest of these setae are about equal to

the radius of the head. According to the position of the lips these setae

vary in attitude. They may be folded together on the front of the head so

as to be in the position of the spokes of a wheel, but they may point

forward when the mouth is partly open, and are in a somewhat spreading

position when the mouth is wide open. The pharynx is on the whole con-

oid, and about three-fourths as deep as the head is wide. Springing from a

little behind its middle is a strong, conical, acute, forward pointing dorsal

tooth, the ventral contour of which lies approximately in the axis of the

*The two most pronounced rows are nearly opposite the edges of the lateral fields,

but there is an irregular median row.

FREE-LIVING FRESH-WATER NEMATODES 95

head. Surrounding the pharynx the muscles are somewhat more powerful

than in the oesophagus immediately behind, so that there is a very faint

pharyngeal bulb. The oesophagus is at first about two-thirds as wide as

the corresponding portion of the neck, but gradually enlarges after passing

through the nerve-ring, so that finally it is two-thirds as wide as the base

of the neck. The lining of the oesophagus is a distinct feature throughout

its length. There is no very distinct cardia. There are no eye-spots. The

amphids, which are about one-third as wide as the head, are spirals of about

two and one-half winds, and are placed opposite the apex of the dorsal

tooth. The intestine, which is separated from the oesophagus by a distinct

constriction, is at first one-half to two-thirds as wide as the body, but in the

greater part of its length is about two-thirds as wide as the body. It is

thick walled, and is composed of cells of such a size that comparatively few

are required to build a circumference, probably about six. The cells con-

tain rather numerous, conspicuous, brownish granules of variable size, the

largest of which have a diameter about equal to double the width of one

of the annules of the cuticle, the smallest of which are very much smaller.

These granules are arranged irregularly, and can hardly be said to suggest

any tessellation. From the broad, raised anus the rectum, which is refractive

and nearly as long as the anal body diameter, extends inward and forward.

The tail is conoid to the subacute conoid spinneret, which has a diameter

about one-eighth to one-tenth as great as that of the base of the tail. There

do not appear to be any caudal setae. The lateral fields appear to be fully

one-third as wide as the body. The nerve-ring surrounds the oesophagus

somewhat obliquely. The excretory pore appears to be situated at a distance

from the anterior extremity about two and one-half times as great as the

width of the head. The renette cell appears to be small and located some

distance behind the base of the neck. From the elevated vulva the vagina

leads inward at right angles to the ventral surface about half way across

the body, where it joins the two-parted uterus. The reflexed, tapering

ovaries reach about two-thirds the way back to the vulva, and contain a

dozen or more developing ova arranged somewhat irregularly, especially

toward the blind end. The rather thin shelled ovate to ellipsoidal eggs are

a little longer than fhe body is wide, and about two-thirds as wide as long.

They have been seen to occur in each uterus one at a time, and are appar-

ently deposited before segmentation begins.

59.

1.7 66 15. -M _— or.

TO snore ag Ser 12 fy

The tail of the male is like that of the female in form and size, but the

anus is more prominently elevated. There is a row of four small pre-anal,

ventral, tubular, protrudable supplementary organs. The final one of these

is opposite the middle of the spicula; the penultimate nearly opposite the

proximal ends of the spicula. The foremost is about three times as far

from the anus as the penultimate. From this it will be seen that the organs

1.6 mm.

96 N. A. COBB

are slightly more nearly approximated to each other posteriorly. These

organs are not conspicuous features, and scarcely disturb the ventral con-

tour. It is possible that each is connected with a unicellular glandular struc-

ture nearby. The two equal, tapering, somewhat arcuate spicula are one and

one-third times as long as the anal body diameter. Their proximal ends

are cephalated by expansion. The accessory pieces alongside are four-fifths

as long as the spicula, and somewhat broader than the spicula. In their

widest part they are one-sixth as wide as the corresponding portion of the

body. They are of rather uniform width throughout. There is a slight

constriction near each end, and the distal extremity appears to be very

minutely dentate. The spicula are about half as wide as the accessory pieces.

The ejaculatory duct is two-thirds as wide as the corresponding portion of

the body, as is also the testis. The blind end is as far behind the base of

the neck as this latter is behind the anterior extremity.

Habitat: Silver Springs, Fla. Flemming solution to glycerine.

ETHMOLAIMUS, de Man, 1880.

Fig. 19, Plate VII.

, : 2.5 102.184 ‘54’ 90.

16. Ethmolaimus americanus, n.sp. as: Ribdeaseiskts ra! ic Jes 4 6 mm.

245 430 5G oe

The thin, transparent layers of the practically naked cuticle are tra-

versed by very fine transverse striae, resolvable with high powers into rows

of closely set dots, which are not modified on the lateral fields. Near the

head the dots are a little coarser than elsewhere on the anterior portion of

the body. On the tail the dots are much farther apart and, though really

arranged in transverse rows, at first glance appear to be scattered irreg-

ularly. The conoid neck ends in a somewhat truncated head, which bears

on its outer margin a circlet of four slender, spreading submedian cephalic

setae, each about half as long as the head is wide. There appear to be

twelve minute papillae in the lip region, which when folded together forms

a rather small, cyathiform cavity, in the midst of which stands the thumb-

shaped, forward-pointing dorsal tooth. This tooth is attached to a dis-

tinctly thickened rib of chitin, which extends from the lip region back to the

base of the pharynx, and is thicker anteriorly than it is posteriorly. This

thickened dorsal rib causes the pharynx to appear somewhat more strongly

built on the dorsal side than on the ventral side. The tooth tapers slightly

to a blunt point, and has a length about one-fourth as great as the width of

the front of the head. Behind it the pharynx is somewhat prismoid and

approximately one-fifth as wide as the head.- It ends abruptly at the base.

The pharynx is surrounded by a pharyngeal bulb, the musculature of which

is set off distinctly from that of the oesophagus, in addition to which there is

a constriction between the bulb and the oesophagus. The somewhat obscure,

slender, apparently spiral amphids consist of about one and one-half winds.

They are located opposite the posterior portion of the pharynx, and are one-

FREE-LIVING FRESH-WATER NEMATODES Q7

third as wide as the corresponding portion of the head. There are no eye-

spots. The oesophagus begins as a tube three-fifths as wide as the base of the

head, and it continues to have this diameter until it expands rather sud-

denly to form a somewhat ellipsoidal or obscurely pyriform cardiac bulb,

which is four-fifths as wide as the base of the neck, and contains an obscure,

elongated, relatively narrow valvular apparatus. The lining of the oeso-

phagus is a distinct feature throughout its length. There is no very dis-

tinct cardia, but the preliminary cells of the intestine are different from those

which immediately follow. The rather thick-walled intestine is separated

from the oesophagus by a deep and distinct constriction, and becomes at

once about half as wide as the body. Thereafter it widens out gradually so

as to become three-fourths as wide as the body. It is composed of cells of

such a size that probably about six to eight are required to build a circum-

ference. The cells contain granules of variable size, the largest of which have

a diameter half as great as that of the terminus of the tail. From the rather

inconspicuous but slightly depressed anus the rectum, which is about as

long as the anal body diameter, extends inward and forward. The body be-

gins to taper slightly from some distance in front of the anus, but tapers

more rapidly behind the anus in such fashion that at the beginning of the

posterior fifth the diameter is about one-sixth as great as at the anus; thence

onward the tail is cylindroid, and ends in a tubular spinneret, less than half

as wide as the terminus. The spinneret tapers slightly to a blunt point, and

is armed at its base with one or more setae as long as itself. The caudal

glands appear to be located in the base of the tail. The lateral fields are

well-developed and fully one-third as wide as the body. The renette cell

appears to be located a short distance behind the cardiac bulb. The position

of the excretory pore is unknown,—possibly it is at the base of the lips.

The nerve-ring surrounds the oesophagus somewhat obliquely. From the

elevated, rather broad vulva the vagina leads inward at right angles to the

ventral surface fully half way across the body, where it joins the sym-

metrically-placed uteri. The reflexed ovaries reach as far back as the vulva,

—at least in specimens in which the uteri contain no eggs. The fully de-

veloped ova are nearly twice as long as the body is wide and about one-

third as wide as long. The form, size and number of the eggs remains un-

determined, but it seems probable that they occur in the uteri one at a time.

Habitat: Spring, Washington Country Club, Chevy Chase, Md.

Sublimate to balsam. .

MONHYSTERA, Bastian, 1865.

Fig. 20, Plate VII.

. 62.

AGF: 220 re 88.

BOs 31); aswee 3.1

The thin, transparent layers of the colorless cuticle are traversed by

about eight hundred transverse striae, resolvable with difficulty into rows of

17. Monhystera sentiens, n.sp. 1.6 mm.

98 N. A. COBB

somewhat dotlike elements. These striae are more readily visible toward

the extremities, especially the posterior extremity. The conoid neck becomes

convex-conoid toward the head, which is somewhat rounded. Throughout

the body there are rather numerous, long, slender somatic setae having a

length equal to the radius of the body. These setae are a little longer toward

the extremities than they are near the middle of the body. On the outer

margin of the head, a trifle in front of the base of the pharynx, there are

ten spreading, tapering cephalic setae, one on each lateral line, and two of

somewhat unequal size on each submedian line. The longest of these setae

are more than half as long as the head is wide. A little more than twice as

far back as the amphids there is a rather definite circlet of cervical or sub-

cephalic setae arranged in submedian positions. The lips appear to be three

in number, and are longitudinally striated or fluted. The thin flap-like, stri-

ated portions are capable of assuming a revolute position. The basal por-

tion of the lip region is considerably thicker than the flaps, and is arched

over the margin of the pharynx. This latter is wide and shallow. Just

beneath the lips it is two-thirds as wide as the front of the head. It closes

together rapidly, so that its base is located at a distance from the anterior

extremity about equal to the radius of the head. In other words, the pos-

terior portion of the pharynx is about half way back to the amphids. These

latter are circular, and one-third to one-fourth as wide as the correspond-

ing portion of the head. Their distance from the anterior extremity is about

equal to half the width of the front of the head. A short distance in front

of each amphid there is a granular nucleus, which closely resembles the

nerve cells that are found in the neck, and seems doubtless to be the nucleus

of the nerve cell which is connected in some way with the function of the

amphids. The oesophagus reaches to the base of the lips, and into it is set

the posterior portion of the pharynx. At first the oesophagus is only two-

thirds as wide as the base of the head. It continues to have this diameter, or

a little more, until after it passes through the nerve-ring. Thence onward it

gradually increases so that finally it is about two-thirds as wide as the base

of the neck. The lining of the oesophagus is a fairly distinct feature. The

intestine, which is separated from the oesophagus by a distinct constriction,

is composed of cells of such a size that probably six to eight are required to

build a circumference. The anterior portion of the intestine is somewhat

bulbous in form, and is separated from the oesophagus on the one side and

the true intestine on the other, by a pair of constrictions. This portion may

be looked upon as a strongly developed cardia. The intestine is moderately

thick walled, and ends posteriorly in a short, wide rectum, hardly as long as

the anal body diameter. The posterior extremity of the female begins to

taper from near the vulva, and continues to taper at about the same rate

behind the tail as in front of it. The tail itself is conoid in the anterior four-

fifths, and cylindroid in the posterior fifth. The terminus is hardly swollen,

and is about one-sixth as wide as the base of the tail. The spinneret is

rounded and bears a couple of submedian setae twice as long as its own

FREE-LIVING FRESH-WATER NEMATODES 99

diameter. The three caudal glands are located in the anterior third of

the tail. The lateral fields vary in width in different parts of the body.

A little in front of the anus they are about two-fifths as wide as the corre-

sponding portion of the body, and contain rather numerous scattered nuclei

of such a size that about eight would be required to reach across the field.

Farther forward the field is narrower, about one-fourth as wide as the

middle of the body. Anteriorly it is wider, about one-third as wide as the

base of the neck. Nothing is known concerning the renette. The nerve-

ring surrounds the oesophagus somewhat obliquely a little in front of the

middle of the neck. From the elevated and rather large and conspicuous

vulva the vagina leads inward at right angles nearly half way across the

body, where it joins the single uterus, which extends forward, and is of

such a size as to contain apparently but one egg at atime. The ovary, which

at first is three-fourths as wide as the body, extends forward and tapers

gradually, so that at the blind end, considerably in front of the cardia and

a short distance behind the nerve-ring, it is one-fourth as wide as the corre-

sponding portion of the body. It sometimes happens that the blind end of

the ovary is disposed in a single coil. The rather thick shelled eggs are as

long as the body is wide, and about three-fourths as wide as long, and appear

to be deposited before segmentation begins. The small spermatozoa found in

the uterus are of such a size that at least ten placed side by side would be

required to span the diameter of one of the eggs. There is a very small,

posterior rudimentary branch to the uterus, which extends backward from

the vulva a distance about equal to two-thirds, the radius of the body.

Around the vulva are four distinct, unicellular ‘vaginal glands.

71.

7 94 22. -M— 87.

107-2" 33°56 A233

The tail of the male resembles that of the female in form and size.

As in the females, the three caudal glands are found in the anterior third

of the tail, and do not extend materially farther forward than the anus.

The two equal, L-shaped, slender, slightly tapering brownish spicula are a

little longer than the anal body diameter. The anterior three-fifths lie nearly

parallel to the body axis, while the posterior two-fifths are arranged nearly

at right angles to the body axis. The distal extremities of the spicula are

slightly widened. At their widest part, namely near the proximal ends, the

spicula are about one-eighth as wide as the corresponding portion of the

body. They are very slightly narrower distally than proximally, where they

are barely cephalated by expansion. The accessory piece is not strongly

developed. The main portion of it lies parallel to the distal two-fifths of the

spicula, and is connected with the dorsal surface of the body by means of

muscles. The ejaculatory duct is one-half as wide as the corresponding

portion of the body. There are two outstretched testes. The blind end of

the anterior testis is located a short distance behind the nerve-ring, while

the blind end of the posterior testis is located about as far in front of the

1.5 mm.

100 N. A. COBB

anus as the terminus is behind it. The testes are broad and some parts appear

to fill up the main portion of the body cavity.

Habitat: Sand bar off Plummer’s Island, Potomac River. Subli-

mate to balsam.

ONCHOLAIMELLUS, de Man, 1886.

Fig. 21, Plate VII.

9 8&5 18 -M- OI.

Ser Wee. -tre e: 1.4 mp

The moderately thick layers of the transparent, naked, colorless cuticle

seem to be destitute of markings of any kind. If there are any striations

they must be exceedingly minute. The conoid neck becomes a little convex-

conoid toward the head, which is subtruncated, and has a lip region almost

imperceptibly expanded. There are ten long, curved, tapering, cephalic

setae, located a trifle in front of the middle of the pharynx, two lateral, and

eight submedian. The members of the submedian pairs are placed one in

front of the other, the hinder members being only about two-thirds as long

as the forward members. It is the forward members that are in the same

circlet with the lateral setae. These latter are about as long as the longest

submedian setae. The bases of the lips are nearly as thick as the wall of

the head, but they gradually become quite thin, though the flaps are not so

marked as they usually are in Oncholaimus. There are six lips, and each

bears on its anterior surface, near the margin of the head, a somewhat out-

ward pointing, minute, innervated papilla, which does not very markedly in-

terfere with the contour of the front of the head. The somewhat cylindroid

pharynx is about twice as long as the front of the head is wide, and the

average diameter of the cavity is a little more than one-third of its length.

At the middle the pharynx is about half as wide as the corresponding por-

tion of the head. Its walls are fairly well chitinized, and appear to be des-

titute of onchi. The description is derived from a single specimen, in which

the mouth is filled with detritus, and it is possible that very minute teeth

might have escaped observation, but this does not seem at all probable.

The bottom of the pharynx where it, is set on the end of the oesophagus, is

in the shape of a broad, shallow, hollow cone. At a distance from the

anterior extremity twice as great as the length of the pharynx the amphids

are seen. These are somewhat elongated, roughly ovate in contour, and

more distinctly marked anteriorly than posteriorly. The anterior border is

a curved, chitinous structure about one-third as wide as the corresponding

portion of the head. Slightly behind the anterior border the amphid has its

greatest diameter. It is about as long as the corresponding radius of the

head, and is extended backward by an apparently tubular structure, which

soon becomes indefinite. Viewed dorso-ventrally the amphids appear like

rather deep invaginations of the cuticle, and each occupies fully half of the

18. Oncholaimellus heterurus, n.sp.

FREE-LIVING FRESH-WATER NEMATODES IOI

corresponding radius of the neck, and opposite them the oesophagus is a

trifle narrower than it is either in front of or behind them. The oeso-

phagus, which at first is about half as wide as the base of the head, con-

tinues to have approximately the same diameter until after it passes through

the nerve-ring, which is somewhat in front of the middle of the neck. Be-

hind the nerve-ring the oesophagus becomes somewhat wider, and is finally

about two-thirds as wide as the base of the neck. The lining of the oeso-

phagus is a fairly distinct feature. The intestine, which becomes at once

nearly three-fourths as wide as the body, is set off from the oesophagus by

a distinct constriction. There does not appear to be any well developed car-

dia. The cells composing the intestine contain scattered granules, which

give rise to a very obscure tessellation, and also contain doubly refractive

granules, which, however are not spherical in form, though their diameter

in different directions is not very variable. The tail of the male tapers rap-

idly from the anus, so that at the end of the anterior fourth it has a

diameter but little greater than that of the terminal spinneret. Near the an-

terior end of the cylindrical part there occur a pair of subventral arcuate,

tapering setae, which are about as long as the corresponding diameter of

the tail. In front of these there is a ventrally submedian pair of papillae,

and also there is a dorsally submedian pair a little in front of these latter.

The spinneret is of a simple character, and has the terminus almost imper-

ceptibly swollen. There do not appear to be any setae on the spinneret.

A trifle in front of the proximal ends of the spicula there springs from a

ventrally submedian lines a somewhat weakly developed bursa, which extends

slightly beyond the body contour, but only does this in front of the anus.

It recedes into the cuticle at a point slightly in front of the caudal setae.

This bursa does not have any ribs and is not striated in any way. The two

equal, elongated, rather uniform, slightly cephalated spicula are a little

more than twice as long as the anal body diameter, and in their anterior

halves are nearly straight. In their posterior halves they are slightly

arcuate. At the point where they attain their greatest width they are about

one-fourth as wide as the corresponding portion of the body. Seen dorso-

ventrally they are somewhat narrower and straighter than when seen in

profile. The accessory piece appears to be compounded of a number of

small chitinous elements, the whole structure being a little less than one-

third as long as the spicula. It is not very strongly developed, and is not a |

very conspicuous feature. The ejaculatory duct is about half as wide as the

corresponding portion of the body. There are two testes outstretched in

opposite directions. The blind end of the anterior testis is about as far be-

hind the base of the neck as this latter is behind the anterior extremity.

The posterior testis is smaller, but just how much smaller is unknown, as

its blind end could not be located in the single specimen examined. Little or

nothing is known concerning the lateral fields and the renette.

Habitat: Fresh water pond, near Ocala, Fla. Bouin solution to

glycerine.

102 N. A. COBB

Note: There is some doubt as to whether this species should be as-

signed to the genus Oncholaimellus for the following reasons: There are

no pharyngeal teeth. The amphid varies somewhat from that of the type

species. The spicula are of equal size, whereas in the type species one of the

spicula is only half as long as the other.

CEPHALOBUS, Bastian, 1865.

Fig. 22, Plate VIII.

Ti TS. el ks 04.

1,.62:403017 23104 ae 23

The thin, transparent, colorless layers of the naked cuticle are traversed

by about seven hundred plain, transverse striae, resolvable with high powers

without very much difficulty. The conoid neck becomes convex-conoid to-

" ward the obscurely lobed head, which is rounded in front, and is set off by

an almost imperceptible, broad, exceedingly shallow constriction. There are

no cephalic setae, and no eye-spots; no amphids have been seen. There are

three rather distinct, bluntly conoid lips, which are rounded in front, each

of which apparently has two inconspicuous innervated papillae. The open

vestibule leads to a conoid pharynx, which is about one and one-half times

as long as the lip region is wide, and tapers from front to back in a com-

paratively uniform way. Between the lips it has a width about one-third as

great as that of the lip region. The posterior half of the pharynx rests in

the anterior end of.the oesophagus, which enlarges very perceptibly, so that

a little behind the base of the pharynx it is more than half as wide as the

corresponding portion of the head. It continues to have relatively much

the same width until near the middle, where it is about three-fifths as wide

as the middle of the neck. There it suddenly diminishes in size so as to be

only one-fourth to one-fifth as wide as the corresponding portion of the

neck. Passing through the nerve-ring with this narrow diameter it finally

enlarges to form an ellipsoidal cardiac bulb about two-thirds as wide as the

base of the neck, containing a rather distinct triplex but not very complex

valvular apparatus of the form usually seen in this genus. There is no very

definite cardia. The intestine, which is separated from the oesophagus by

a rather broad and shallow constriction, is at first only half as wide as the

corresponding portion of the body. It soon becomes thicker walled, and

enlarges so as to be three-fourths as wide as the corresponding portion of

the body. It is composed of cells of such a size that probably only about

two are required to build a circumference. The contents of the cells are not

distributed so as to give rise to anything distinct in the way of tessellation.

The posterior lip of the anus is very slightly elevated. From the anus the

rectum, which is somewhat longer than the anal body diameter, leads inward

and forward. The rectum is separated from the intestine by a rather dis-

tinct constriction. The tail is at first convex-conoid, the convexity existing

19. Cephalobus sub-elongatus, n.sp. .6 mm.

FREE-LIVING FRESH-WATER NEMATODES 103

—

almost entirely on the dorsal surface. Through the middle third the tail

tapers much more rapidly than elsewhere, so that at the beginning of the

posterior fourth it has a diameter no more than one-fifth as great as at the

anus. Thence onward it is conoid to the acute terminus. There is no spin-

neret. Very little is known concerning the lateral fields, but at the middle

of the body they appear to be one-third as wide as the corresponding portion

of the body. There do not appear to be any distinct wings. The excretory

pore is located opposite the nerve-ring. This latter surrounds the oesophagus

obliquely, and is accompanied by nerve cells, of which the greater number

are behind the nerve-ring and in front of the cardiac bulb. From the mas-

sive elevated vulva the rather strongly chitinized, slightly colored vagina

leads inward at right angles to the ventral surface nearly half way across

the body, where it joins the single uterus, which extends forward. In speci-

mens which do not yet contain fully developed eggs, and in which the uterus

is occupied by spermatozoa, the flexure in the sexual apparatus occurs about

half way between the vulva and the base of the neck. The ovary extends

straight backward, and finally tapers to a blunt end a short distance in front

of the anus. At the rear end the ovary is one-half as wide as the corre-

sponding portion of the body. The ova appear to be arranged more or less

single file in the greater part of the ovary, whose walls contain distinct

nuclei of relatively large size. These nuclei are of such a size that about

six to eight placed side by side would reach across the body, and are re-

moved from each other in a longitudinal direction a distance equal to about

two-thirds of the body diameter. None of these cells could be seen in that

portion of the sexual tube in front of the vulva, and it is surmised that the

cells composing the ovarian tube are markedly different in their character

from those composing the tube between the ovary and the uterus and those

composing the wall of the uterus. The spermatozoa have been seen packed in

the uterus somewhat like a roll of coin, though each one is thinner at the

margins than at the center where the nucleus exists. The spermatozoa are

of such a size that the uterus may contain about two dozen, arranged single

file.

Habitat: Moss, Bog. W. End of Douglas Lake, Mich. This species close-

ly resembles C. elongatus de Man, and possibly may prove to be the same. At

present, judging from a single specimen it appears to differ in the following

points: (1) The tail of the female is of different form, since that of elongatus

is nearly conical; (2) No wings have been seen on sub-elongatus, while they

appear to be a marked feature of elongatus; (3) There is no expansion of

the lip region in elongatus as in sub-elongatus; (4) The vulva in sub-elon-

gatus is far more massive; (5) the pharynx in elongatus is more elongated,

and longer as compared with the length of the head; (6) oesophagus is

relatively slenderer in elongatus. Sublimate to balsam.

Zeer Tes FE A ;

20. Cephalobus setosus, n.sp. Sa Ni Gi Ae gt .7 mm.

SF DNAS Oa Po Ae 3:

The moderately thick layers of the naked, transparent, colorless cuticle

are traversed by 425 transverse striae, which are not further resolvable.

104 _ N. A. COBB

The striae are more or less interrupted on the lateral fields by two wings,

or by a single wing indicated by two longitudinal lines. The width of the

wing near the middle of the body is about equivalent to the width of four

of the annules of the cuticle. Toward the tail end the width of the inter-

rupted space is about equivalent to the width of three of the annules, and

near the middle of the neck the width is also about equivalent to that of

three of the corresponding annules. Through the middle of the lateral space

on which the annules are interrupted there passes a longitudinal refractive

line. The posterior portion of the neck is cylindroid; the anterior half

conoid to the head, which is not set off in any way. The lips are arranged

in two series: an outer series of six two-parted lips, and an inner series of

three obscurely two-parted projecting flaps, each armed at the anterior

rounded corners with short, arcuate, tapering, acute, forward-pointing

bristles. Each of the two parts of the six outer lips or appendages is con-

oid and acute, and the spaces separating them are much narrower than those

separating the lips themselves. At the base of each of the lateral two-parted

lips there is a transverse mark, which may possibly be the outer expression

of the amphid. This marking is very minute and about four times as wide

as it is long, and is placed transversely on the base of the lip, just in front

of the foremost cervical annule. It spans about one-sixth of the width of the

head at this point. The three inner appendages, which may more properly

be termed the lips, are about as long as they are wide, and seem to be flex-

ible. They rather closely surround the mouth opening. Each is half as

wide again at its free extremity as it is at the base, and the total length is

about equal to one-fourth of the diameter of the front of the head. The

setae with which these lips or flaps are armed are about two-thirds as long

as the flaps themselves. The rather obscure, narrow, cylindroid pharynx

is about as long as the base of the head is wide, and its lumen is hardly

wider than the thickness of the cuticle. The oesophagus surrounds the

pharynx, but is narrower in this region than it is immediately behind the

pharynx. Behind the pharynx it commences as a tube about three-fifths as

wide as the base of the head, and continues to have about the same diameter

until after it passes through the nerve-ring. It does increase a trifle in

diameter, however, so that at the nerve-ring it is about one-half as wide as

the corresponding portion of the neck. Some distance behind the nerve-ring,

namely, at a distance about equal to one and one-half diameters of the neck,

there is a slight break in the musculature of the oesophagus. Behind this

break the oesophagus begins to taper very gradually and continues to de-

crease in diameter until it finally expands to form the somewhat ellipsoidal or

pyriform cardiac bulb, which is about two-thirds as wide as the base of the

neck, and contains a distinct, rather simple, triple, chitinized valvular appa-

ratus. That portion of the oesophagus immediately in front of the cardiac

bulb has a diameter about one-fourth as great as that of the corresponding

portion of the neck. The lining of the oesophagus can be seen throughout its

length, and is a fairly distinct feature. The intestine which at first is thin-

FREE-LIVING FRESH-WATER NEMATODES TOS

walled is separated from the oesophagus by a distinct and deep constriction,

and becomes at once about three-fourths as wide as the body. The anterior

portion of the intestine is characterized by the presence of a considerable cav-

ity, which, however, soon narrows, and, as the internal wall of the intestine

is rather strongly refractive, the narrow, sinuous lumen is a very conspicuous

feature. From the rather conspicuous depressed anus the rectum, which is

rather strongly chitinized and somewhat longer than the anal body diameter,

extends inward and forward. The tail is somewhat concave conoid from

the anus to the very acute terminus. There are no caudal glands. The lat-

eral fields appear to be about one-third as wide as the body. The nerve-

ring surrounds the oesophagus somewhat squarely. The excretory pore

appears to be located near the nerve-ring. The nature of the internal sexual

organs remains uncertain, but the vulva is evidently located near the middle

of the body. The description is derived from an immature specimen.

Habitat: Cranberry bog, Arlington Farm, Virginia. Flemming so-

lution to glycerine.

BASTIANA, de Man, 1876.

Fig. 23, Plate VIII.

2 8° 18) 58, So.

21. Bastiana exilis, n.sp. iii air set BS 1.4 mm,

Rte Rare, ee Ee

The moderately thick layers of the transparent, colorless, naked cuticle

are traversed by about eight hundred forty transverse striae, which do not

appear to be further resolvable. These striae exist in the outer as well as

inner cuticle, so that the entire contour of the body is crenate. Rather con-

spicuous lateral wings are present, the optical expression of which is two

distinctly refractive longitudinal lines opposite the lateral fields, separated

from each other by a distance somewhat greater than the width of one of

the annules of the cuticle. The gradually tapering conoid neck ends in a

somewhat truncate head, which is not set off in any way, and which bears

a circlet of at least six cephalic setae, of which four submedian are the

longer, and somewhat longer than the head is wide. Possibly each of these

latter is accompanied by a shorter seta, thus making ten in all. Apparently

labial papillae are present, but they have not been sufficiently clearly seen

to permit of enumeration. There is no distinct pharynx. The amphids, lo-

cated as in B. gracilis deMan, are somewhat in the form of the end of a

shepherd’s crook. They are perhaps to be regarded as broad spiral bands of

about one turn. So regarded, the band may be conceived to begin on the

ventral side where its end is rounded and its contour distinct, pass forward,

and then curve backward and end indefinitely at a point somewhat in the

rear of the beginning. The amphids are half to two-thirds as wide as the

corresponding portion of the neck, and somewhat longer than wide. There

are no eye-spots. The oesophagus begins as a tube fully two-thirds as wide

as the head. It gradually increases in diameter as it passes backward, and at

106 N. A. COBB

its posterior extremity is three-fourths as wide as the base of the neck.

There is no definite cardia. The lining of the oesophagus is indistinct. The

intestine, which is separated from the oesophagus by an obscure constriction,

becomes at once three-fourths as wide as the body, is rather thick walled,

and its cells contain rather uniform, colorless granules, not arranged in any

definite manner. From the rather raised anus the conspicuous rectum, which

is twice as long as the anal body diameter, extends inward and forward.

The tail is conoid, but tapers more rapidly near the acute terminus. A short

distance in front of the terminus it is nearly half as wide as at the base.

Nothing is known concerning the renette. The lateral fields have not been

distinctly seen, but they appear to be about one-third as wide as the body.

Nothing definite is known concerning the internal sexual organs, as the spect-

mens examined were not fully developed.

28.

4°56. 19,. -~M-. 92.

AAPG: Be Pewe We rep ia

The tail of the male is like that of the female in form and size,

except that the anus is more prominently raised. In front of the anus

and extending forward to the base of the neck there is a ventral row of

ninety supplementary organs. These are of small size, and each ap-

pears when seen in profile to be a slight conical, innervated elevation

having an altitude about one-third as great as the width of its base.

These organs are removed from each other a distance on an average

about equal to the radius of the body or a little more. They are some-

what nearer together posteriorly than anteriorly. Near the base of the

neck the distance between two adjacent organs is about equal to the

body diameter. The two equal, tapering, acute, nearly straight spicula

are about one and one-third times as long as the anal body diameter.

They are slightly cephalated by expansion, the cephalum occupying

about one-third of the length. At the widest part, namely in the cephala,

the spicula are one-fourth to one-third as wide as the corresponding

portion of the body. They do not appear to have any accessory pieces.

The spicula appear, when seen in profile, to be arranged at an angle

of forty-five degrees to the body axis. Beginning at. the anus and ex-

tending obliquely backward there is a strand of muscle which is at-

tached to the dorsal side of the body. The two testes are outstretched

in opposite directions. The blind end of the anterior testis is about as

far behind the base of the neck as the nerve-ring is in front of it, while

the blind end of the posterior testis is about twice as far in front of

the anus as this latter is in front of the terminus.

Habitat: Fresh water, Tynne Station, Fla. Bouin solution to gly-

cerine.

1.4 mm.

FREE-LIVING FRESH-WATER NEMATODES 107

APHANOLAIMUS, de Man, 1880.

Fig. 25, Plate VIII.

43.

: ue 5 88 Sa BO

22. Aphanolaimus spiriferus, n.sp. : enh Le = 1.5 min.

T Stele road 1.9

The thin, transparent layers of the colorless, naked cuticle are traversed

by about one thousand transverse striae, which do not appear to be further

resolvable, or at any rate are resolvable with difficulty. The cuticle is also

traversed by longitudinal striations, manifestly due to subcuticular struc-

tures,—the submedian fields—and the attachment of the muscle cells. The

contour of the body is minutely crenate. There is a distinct wing extending

throughout the length of the body, whose presence is indicated by two re-

fractive lines occupying a space hardly greater than the width of one of the

annules of the cuticle. On being carefully examined these lines show traces

of the striations of the cuticle. The conoid neck ends in a somewhat rounded

head, whose lip region is set off by a minute constriction just in front of

the amphids. The contour of the front of the head is rounded, or, like

that of a very flat truncated cone. In the midst of the truncation there is

an exceedingly minute depression, the mouth pore. There does not appear

to be any very distinct pharynx, but the lining of the oesophagus is slightly

altered in the region of the head back as far as the posterior margins of the

amphids. It is not unlikely that this represents a distinct, though rudi-

mentary pharynx. The species, however, would naturally at first sight be

classed as being without a pharynx. The oesophagus begins as a tube about

half as wide as the base of the head, and expands very gradually until after

it passes through the nerve-ring. At the nerve-ring its width is about one-

third that of the corresponding portion of the neck. Behind the nerve-ring

the oesophagus begins to expand a little more rapidly, though still slowly.

When it reaches the end of the neck it is half as wide as the base of the

neck. For a distance equal to one body diameter, however, it decreases in

size, so that where it joins the intestine it is very narrow, only about one-

fifth as wide as the corresponding body diameter. Nevertheless, there ap-

pears to be a distinct, though exceedingly minute cardia. The lining of the

oesophagus is a fairly distinct feature throughout its length. The intestine,

which is at first thin-walled, gradually becomes half as wide as the body, and

is composed of cells of such a size that only two or three are required to

build a circumference. For the most part the wall of the intestine is moder-

ately thick. From the very slightly raised, rather inconspicuous anus the

slender rectum, which is about one and one-half times as long as the anal

body diameter, extends inward and forward. It is separated from the in-

testine by a very distinct and deep constriction. Near the middle the lateral

fields are about one-third as wide as the body. The ventral gland is a rather

elongated, saccate cell a little longer than the base of the neck is wide,

and about one-third as wide as long. It contains a large spherical nucleus,

108 N. A, COBB

with a large, fairly distinct nucleolus. There extend backward from

this cell two finger-shaped, submedian extensions nearly as long as the cell

itself. Notwithstanding the distinctness of the organ and appendages the

position of the excretory pore remains to be discovered. The tail tapers

from in front of the anus in such fashion that at the beginning of the

final fourth it has a diameter about one-fourth as great as at the anus.

Thence onward the tail is cylindroid to the terminus, which bears a trun-

cated, conical, unarmed spinneret. The three caudal glands are minute,

close together, opposite to and a little behind the anus. From the slightly

depressed vulva the chitinized vagina leads inward at right angles to the

ventral surface half way across the body, where it joins the two symmetrical-

ly placed uteri. The reflexed ovaries reach about one-third the distance

back to the vulva and contain a few developing ova arranged single file.

The species is viviparous. Two embryos and a developing egg have been

seen in each uterus at the same time. The eggs are somewhat elongated,

about as long as the body is wide, and a little less than half as wide as they

are long.

cpa ts Moline © oh Ee WO. taras 3

hc Gas Ba hee 2A PED

The tail of the male is like that of the female in form and size. In

front of the anus there is a ventral series of seven tubular, protrudable, sup-

plementary organs, occupying a space nearly equal to the length of the tail.

The hindermost is opposite the proximal ends of the spicula. Each of these

organs is about half as long as the body is wide, has its proximal end slightly

cephalated by expansion, and its distal end slightly curved. The circular

apertures through which the organs are protruded disturb the ventral con-

tour distinctly, each of them occupying a space about equal to the width of

four annules of the cuticle. There are no special setae or papillae either in

front of the anus or behind it. The two equal, uniform, slender, very

strongly arcuate spicula are about one and one-half times as long as the

anal body diameter, and their proximal ends are cephalated by expansion.

The proximal ends lie nearly opposite the body axis. There is a simple ac-

cessory piece, applied for a short distance to the distal ends of the spicula,

having a backward pointing process two-thirds as long as the anal body

diameter.

Habitat: Potomac River, Washington, D. C. Sublimate to balsam.

7233 By 207 EO dl coat

; By FRSA BO ABS

The moderately thin, transparent layers of the colorless, naked cuticle

are traversed by fine transverse striae, resolvable with moderate powers,

and not modified on the lateral fields. The presence of wings is indicated

by two lines extending from near the middle of the neck well onto the tail.

1.5 mm.

23. Aphanolaimus minor, n.sp.

FREE-LIVING FRESH-WATER NEMATODES I0Q

These occupy a space a little more than the width of one of the annules of

the cuticle, but sometimes one of these lines is more prominent than the

other. The conoid neck ends in a rounded head, which is not set off in any

way. There are no cephalic setae. There does not appear to be any distinct

pharynx. The lining of the oesophagus is slightly modified back twice as

far as the posterior margins of the amphids, and very likely this portion of

the tube may be regarded as a narrow rudimentary pharynx. Twice as far

from the anterior extremity as the base of this supposed pharynx. the

oesophagus is distinctly interrupted by a break in the musculature, although

there is no change in size, and just behind this break there are three distinct,

elongated nuclei, one in each segment of the oesophagus. These appear-

ances are reminiscent of the arrangement in Plectus, to which Aphanolaimus

is doubtless related. There do not appear to be any distinct lips, though

possibly there may be three exceedingly minute, well amalgamated, flattish

ones. Although at first glance the amphids appear to be circular, they are

really spiral in form. They are about one-fifth as wide as the corresponding

portion of the neck. Their distance from the anterior extremity is about

equal to the diameter of the head; or in other words, their centers are re-

moved from the anterior extremity a distance about twice as great as their

diameter. The amphids appear to be slightly larger in the male than in the

female. There are no eye-spots. The oesophagus begins at the base of the

above described pharynx, as a tube about half as wide as the corresponding

portion of the neck. It widens very gradually, so that where it passes

through the nerve-ring it is nearly one-third as wide as the corresponding

portion of the neck. At the middle, nearly opposite the nerve-ring, there

is an almost imperceptible increase in diameter, indicative of a deteriorated

median swelling. Finally, it expands into the narrowly pyriform cardiac

swelling destitute of any distinct valvular apparatus. This swelling is half

to two-thirds as wide as the base of the neck. The lining of the oesophagus

is a distinct feature throughout its length. There is no distinct cardia. The

intestine, which is at first only one-fifth as wide as the base of the neck,

joins the middle of the posterior surface of the cardiac swelling. It is

moderately thick-walled, and gradually becomes about two-thirds as wide as

the body. It appears to be made up of cells of such a size that few, prob-

ably two or three, or possibly four, are required to build a circumference.

The body tapers gradually from a long distance in front of the anus. This

latter is very slightly raised, more particularly on the anterior margin. From

it the rectum, which is about as long as the anal body diameter, extends in-

ward and forward. The tail is conoid in the anterior three-fourths. The

posterior fourth is cylindrical and has a diameter nearly one-third as great

as that of the base of the tail. It ends in a rounded, unarmed spinneret, bear-

ing an apiculum. The lateral fields appear to be about one-third as wide as

the body. The nerve-ring surrounds the oesophagus somewhat obliquely.

There appears to be a small renette cell opposite the anterior portion of

the intestine, but the position of the excretory pore has not been discovered.

IIo Ne tAL (COBB

From the inconspicuous vulva the vagina leads inward at right angles to the

ventral surface about half way across the body, where it joins the two sym-

metrically-placed uteri. The reflexed ovaries reach about half way back

to the vulva and contain half a dozen or more developing ova arranged

somewhat irregularly. The thin-shelled, ellipsoidal eggs are about as long

as the body is wide and about three-fifths as wide as long. They have been

seen in the uterus one at a time, and apparently are deposited before seg-

mentation begins.

3. 15. 23. -M- 85.

BS ose eS Base aut

The tail of the male is conoid in the anterior three-fourths in such

fashion that the beginning of the final fourth has a diameter of about one-

eighth that of the base of the tail; thence onward the tail is nearly cylin-

drical or expands slightly, and ends in a rounded terminus bearing an api-

culum forming an unarmed spinneret. The caudal glands are located in the

base of the tail. In front of the anus in the male there is a ventral row of

eight or nine protrudable, obscurely S-shaped, yellowish supplementary or-

gans. These appear to be of rather uniform size and are equally spaced.

Their length is somewhat greater than that of the radius of the body, and

they are placed at an angle of about thirty degrees to the body axis. They

are of rather uniform diameter throughout their length, but taper a little

toward the blunt distal extremity, and are obscurely cephalated at the

proximal ends. The distal extremity of the hindermost of these organs is

located nearly opposite the proximal ends of the spicula. The entire distance

occupied by the series is about one and one-half times as great as the length

of the tail. The two equal, tapering, strongly arcuate, brownish yellow spicula

are about one and one-half times as long as the anal body diameter. Their

proximal ends are cephalated by expansion, and extending from the proximal

ends toward the distal extremities there are straight, refractive lines indicat-

ing possibly that there is more to the framework of the spicula than appears

at first glance. The spicula curve inward and backward to near the dorsal!

side of the tail, and then pass forward so that their proximal extremities lie

opposite the body axis. The spicula are accompanied by a rather straight,

slender, slightly tapering, blunt accessory piece applied to their distal fifths.

From this point the accessory piece extends inward and backward at an

angle of sixty degrees, and ends a little to the dorsal side of the

body axis. At their widest part, just behind the cephala, the spicula

have a width about one-fifth as great as that of the corresponding portion of

the body. A little behind the middle of the tail there are two ventrally sub-

median setae, about half as long as the corresponding diameter of the tail.

The ejaculatory duct is about one-third as wide as the body. There are two

testicles, one extending forward and the other backward. The blind end of

the anterior testicle is a little farther behind the base of the neck than the

mm.

Ce a a oe

a Te ee

FREE-LIVING FRESH-WATER NEMATODES II!

nerve-ring is in front of it. The blind end of the posterior testicle lies just

in front of the anterior supplementary organ.

Habitat: Mud, Potomac River. Sublimate to balsam.

TYLENCHUS, Bastian, 1865.

27) | 300 a

24. Tylenchus symmetricus, n.sp. aot Ratelse pin [Yon cM ats .7 mm,

si Pe. Fae ER fo ee iy

The moderately thick layers of the transparent, colorless, naked cuticle

are traversed by fine plain transverse striae, which are not further resolvable.

There are two wings on the lateral fields, removed from each other a dis-

tance about equal to one-fourth to one-fifth the body diameter. The space

between these wings is very faintly marked with longitudinal lines, of which

two near the middle are more prominent than the others. The wings them-

selves bear traces of transverse striation. These wings begin near the

middle of the neck and end on the tail. The conoid neck becomes convex-

conoid toward the somewhat rounded head, which is not set off, or at least

only by an almost imperceptible constriction a short distance behind the lip

region. There are no distinct lips. What appear to be the faintest possible

traces of papillae may be seen on the lips, but these do not disturb the rounded

contour of the head. Were it not for the innervations it would be prac-

tically impossible to see them. The pharynx is tubular and just wide enough

to make a passage for the spear. This latter is slender, nearly one and one-

half times as long as the base of the head, and has a three-bulbed base about

one-fifth to one-fourth as wide as the corresponding portion of the head.

Near the middle the spear is closely surrounded by a rather inconspicuous

guiding-ring or cylinder, about one-fourth as long as the spear. At its

widest part, namely, in the proximal half, the diameter of the spear is less

than the width of two of the adjacent annules of the cuticle. The oesophagus

begins as a tube about one-third as wide as the base of the head, and con-

tinues to have this diameter until it expands to form the ellipsoidal or pro-

late median bulb. This latter is about three-fifths to two-thirds as wide as

the middle of the neck, and contains a distinct ellipsoidal valvular apparatus

about one-fifth as wide as the bulb itself. Behind the median bulb the

oesophagus is smaller than elsewhere. For a distance equal to twice the

width of the neck it has a width only about one-eighth to one-sixth

as great as that of the corresponding portion of the neck. There-

after, it expands to form the elongated-pyriform non-muscular cardiac swell-

ing, which is half as wide as the base of the neck, and contains a rather

conspicuous nucleus. The lining of the oesophagus is a fairly distinct feature

in its anterior part; but posteriorly it is much less distinct, and is very diffi-

cult to observe in the cardiac swelling. The intestine, which is separated

from the oesophagus by an indistinct constriction, becomes at once fully two-

thirds as wide as the body. Its cells are packed with large granules of some-

what variable size, the largest of which have a diameter about one-eighth as

great as that of the body, the smallest being considerably smaller. These

112 N. A. COBB

granules are so prominent as to obscure the cellular structure of the in-

testine. From the very slightly elevated and rather inconspicuous anus the

rectum, which is hardly as long as the anal body diameter, extends inward

and forward. The tail is conoid to the terminus, where it rather suddenly

tapers much more rapidly to a very acute point. This rapidly tapering por-

tion has a length about equal to one-fourth the anal body diameter, and the

diameter at the point where the change in taper begins is about equal to one-

fifth of the anal body diameter. The lateral fields appear to be a little more

than one-third as wide as the body. The nerve-ring surrounds the oesopha-

gus obliquely. The excretory pore is located a little behind the nerve-ring, a

little more than half way from the base of the neck to the middle of the

median bulb. From the slightly elevated, rather massive vulva the vagina

leads inward at right angles to the ventral surface nearly half way across

the body, where it joins the two uteri. Apparently the ovaries are out-

stretched. A single egg has been seen in one of the uteri. It is about twice

as long as the body is wide and about one-third as wide as long. It is thin-

shelled and apparently undergoes segmentation before being deposited.

28735) 320.5 M804

Pet Ht ae SY eat tae 9 Va Ber A RY

The tail of the male is like that of the female in form. From the raised

anus it is arcuate-conoid to the terminus, which is concave-conoid and ends

in an exceedingly fine slender point. The length of the terminus is about

one-third as great as the anal body diameter, while its diameter is about

one-fourth as great as the anal body diameter. There are no supplementary

organs, nor have any special papillae been seen either in front of the anus

or behind it. There is a fairly well developed, but not very prominent bursa,

which extends but little beyond the ventral contour at any point. It springs

from the submedian lines at a distance as far in front of the anus as the

middle of the tail is behind it. The bursa is striated like the cuticle, and its

margin is entire; it extends to near the end of the tail. Near the middle

of the tail there appears to be a bursal rib on each side, which does not

reach to the margin of the bursa. The ejaculatory duct is about one-third

as wide as the body. The blind end of the single outstretched testicle lies

a short distance behind the base of the neck.

Habitat: Marsh in black clay with much decayed vegetation, near Jm-

patiens, Arlington Farm, Virginia. Flemming solution to glycerine.

6 mm.

RHABDITIS, Dujardin, 1845.

12 108 °168 ‘55’ 938

T2e 8 ea Osa ae

The thin layers of the transparent, naked, colorless cuticle are traversed

by transverse striae, which are resolvable with high powers and appear to be

resolvable into rows of dots, but there is some doubt about this. The cuticle

25. Rhabditis punctata, n.sp. 1.8 mm.

FREE-LIVING FRESH-WATER NEMATODES 113

is longitudinally striated. Near the middle of the male there is a lateral area

nearly half as wide as the body, which is nearly destitute of striations. On

either side of this field the cuticle may be seen with high powers to be dis-

tinctly longitudinally striated. This lateral field narrows toward both ex-

tremities so as to be hardly wider than the spicula, so that the main portion

of the cuticle of these regions appears there to be longitudinally striated.

The neck is conoid, becoming almost imperceptibly convex-conoid toward

the head, which is somewhat rounded and bears six lips, which are fairly

well separated from each other, and each of which appears to be papillate.

The simple, unarmed pharynx is cylindrical and one-third as wide as the

hase of the head. Its cavity is four to five times as long as wide. No amphids

have been seen, and there are no eye-spots. The oesophagus receives the

base of the pharynx and becomes at once about two-thirds as wide as the

base of the head. It continues to have this diameter until it expands to

form the ellipsoidal median swelling, which has a distinctly radiated fibrous

structure. This swelling is about two-thirds as wide as the corresponding

portion of the neck, and is separated from the portion of the oesophagus

preceding it, as well as the portion succeeding it, by a refractive division in

the internal musculature. Behind the median swelling the oesophagus has

a diameter less than half as great as that of the corresponding portion of

the neck, and it narrows continuously until it reaches the pyriform cardiac

bulb, which is three-fourths as wide as the base of the neck and contains a

well developed, complicated, chitinous valvular apparatus half as wide as

the bulb itself. There is no distinct cardia. The somewhat transparent and

colorless intestine, which is separated from the oesophagus by a distinet

constriction, is composed of cells containing scattered granules of variable

size, the largest of which have a diameter somewhat less than the thickness

of the cuticle, and the smallest of which are very much smaller. The anus

is slightly raised, and from it the rectum, which is one and one-half times as

long as the anal body diameter, leads almost directly forward. The body

tapers for some distance in front of the anus; from the anus onward it is

conical to the acute terminus. There is no spinneret, and there are no caudal

glands. Nothing definite is known concerning the renette cell. The excre-

tory pore is located about half way between the median and posterior bulbs,

just behind the oblique nerve-ring. The two uteri extend in opposite direc-

tions, and the ovaries are reflexed, the flexures occurring the one not far

behind the base of the neck and the other not far in front of the anus.

The mature females contain scores of eggs in various stages of development,

the most advanced containing well-developed embryos.

2.3 162 25.9 -M 063

Piet 5 te eG

The tail of the male is conoid from the anus in such fashion that at the

beginning of the posterior third it has become reduced to a mere striated

nearly straight spine, which is no wider than one of the ribs of the bursa.

I, mm.

114 N. A. COBB

The dorsal contour of the tail continues as a more or less regular extension

of that of the body. The ventral contour, however, is elevated at the anus;

at any rate, when the spicula are partly extruded. This elevation appears to

be largely median, and there is a distinct groove on either side between it and

the bursa. When this groove is brought into optical section and the anal

elevation is disregarded the tail appears to be asymmetrically conoid. The

two equal, brownish, nearly straight spicula are fully twice as long as the

tail, or one and one-half times as long as the body diameter, measured oppo-

site the proximal ends of the spicula. The spicula in the distal three-fourths

taper to a blunt point. At their widest part, considerably in front of the

middle, they are one-fourth to one-fifth as wide as the corresponding portion

of the body. In the proximal fourths the spicula are rather suddenly nar-

rowed and terminate in bulbs or cephala, which have a diameter twice as

great as the portion of which they are expansions. Parallel to the spicula

there are accessory pieces. These are two-thirds to three-fourths as long as

the spicula, which they partially envelop. They are about as strongly chitin-

ized as the spicula themselves. The transparent, colorless bursa springs

from the submedian lines, nearly opposite the proximal ends of the spicula,

and when seen in profile only slightly exceeds the ventral contour in front

of the anus, but behind the anus exceeds the ventral contour of the tail

Proper so much that nearly the entire length of the ribs comes plainly into

view. The ribs are arranged in three groups: (1) Two ribs close together

opposite the middle of the spicula. (2) Four ribs close together opposite to,

and a trifle behind the anus. (3) Four ribs of which three are very close

together, and one a little farther forward, the whole group being opposite

the middle of the tail. Most of these ribs reach to the margin of the bursa,

which is entire and is not distinctly striated. The outer members of the

middle and posterior groups do not reach quite to the margin. The ejacu-

latory duct is nearly one-half as wide as the body. The single, outstretched

testicle has its blind end located about half as far behind the base of the

neck as this latter is behind the anterior extremity. At its blind end the

testicle is about one-third as wide as the body. It gradually increases in

width, so that it occupies four-fifths of the diameter of the middle of the

body. The spermatocytes are of large size, one-third to one-half as wide

as the body.

Habitat: About the roots of aquatic plants, Potomac River, Washing-

ton. 6G:

TRILOBUS, Bastian, 1865.

Fig. 15, Plate VI.

26. Trilobus longus, (Leidyv), Bastian NSARM Yi 1.2 mm.

ee aie 2 ee Ov BE

The thin, transparent layers of the colorless cuticle are traversed by

exceedingly fine plain transverse striae, more particularly visible in the

FREE-LIVING FRESH-WATER NEMATODES It5

lower layers with high powers. There are short hairs to be found here

and there on the surface of the body, more particularly toward the ex-

tremities. The conoid neck ends in a somewhat rounded head not set

off by any constriction. The cephalic setae appear to be ten in number

(eight submedian and two lateral), outward pointing, each about one-

sixth as long as the head is wide, and placed on the outer margin of the

front of the head opposite the posterior portion of the pharynx. The

members of the submedian pairs are, however, of unequal size. There

are six small, pointed lips surrounding the mouth opening. It is cer-

tain that these lips bear papillae, but the number is not known. Lat-

eral organs in the form of somewhat stirrup shaped markings one-

fourth as broad as the corresponding portion of the head, occur at a

short distance behind the base of the rudimentary pharyngeal cavity.

This latter is a more or less triquetrous cyathiform cavity having its

walls distinctly chitinized and bearing at its base one or more protuber-

ances near the point where the lumen of the oesophagus begins. One

of these is a ridge, the others minute teeth. The average width of the

main pharyngeal cavity is about one-third that of the head. The oeso-

phagus is slightly expanded to receive the pharynx, but otherwise be-

gins as a tube about three-fifths as wide as the anterior part of the

neck, and expands very gradually to the end, where it is a little more

than half as wide as the base of the neck. The lining of the oeso-

phagus is a distinct feature throughout its length. There is a distinct

rounded cardia. The intestine, which becomes at once about two-fifths

as wide as the body, is separated from the oesophagus by a distinct

constriction, in which lie the three granular bodies whose presence

gave origin to the name of the genus. The intestine is relatively thick

walled, its small cells containing scattered granules of small size, which

are not arranged in any very definite manner. The intestine frequently

contains diatoms in large numbers, thus indicating that these are a

common source of nourishment for this species. From the slightly de-

pressed anus the rectum, which is about as long as the anal body

diameter, extends inward and forward to join the intestine, which is

narrowed at its extremity so as to be about two-fifths as wide as the

body. Nothing is known concerning the ventral gland. The longi-

tudinal fields are distinctly developed, being about one-fourth as wide

as the worm itself. The nerve-ring surrounds the oesophagus some-

what obliquely. The tail is conoid in the anterior third in such fashion

that at the beginning of the middle third it has a diameter about one-

fourth as great as at the anus. Thence onward it tapers gradually to

the slightly swollen spinneret or outlet for the caudal glands. These

latter, three in number, are located tandem in the tail opposite to and

slightly behind the anus. From the slightly elevated vulva the vagina

leads inward at right angles to the ventral surface fully half way

across the body. The vagina is bifurcated and extends in opposite di-

116 N. A. COBB

rections, the reflexed ovaries passing about two-thirds the way back to

the vulva. Two or three eggs may occur in each uterus at one time.

These are somewhat ellipsoidal and thin shelled, being about two-thirds

as long as the body is wide and about two-thirds as wide as long. The

eggs appear to indicate at least the early stages of segmentation before

being deposited. The walls of the vagina present the peculiarity of being

very thick, and composed of concentric layers to the number of six or

seven, so that the organ is considerably broader than it is deep. Its in-

ternal wall presents the peculiarity of staining strongly with carmine.

1.3 83 13.7. -M- 02.

BP) pt eee pease h rape

The tail of the male is very much like that of the female in form

and size. Supplementary organs are found in front of the anus only.

These are six in number, of which three are very prominent. The an-

terior member of this group of three is about twice as far in front of

the anus as the spinneret is behind it. The members of this group are

equidistant, the distance between consecutive members being about twice

as great as the diameter of the organs themselves. All three occupy

a distance about twice as great as the corresponding body diameter.

Each of these organs consists of an internal and an external portion, the

internal portion being a flattish, hemispherical mass of tissue of very

fine, or at least uniform texture. These have a diameter about two-

fifths as great as that of the body at the same part. The external

portion of these organs consists of a ring slightly raised, from which

projects a mammiform papilla which bears a minute median seta or

nerve-ending. When this mammiform portion is traced inward it passes

through the ring on the surface of the body and then bends forward

and ends rather indefinitely in the anterior contour of the internal por-

tion of the organ. These organs possess the peculiarity of staining

strongly with carmine. In addition to the organs already described

there are three others of smaller size, two very minute, one near the

anus and the other opposite the proximal portions of the spicula. The

third, which has a size intermediate between those just described and

those first described, is located about half way between the anus and

the posterior member of the larger group. These smaller organs are

comparatively close counterparts of the larger, differing merely in size.

In addition it may be noted that the cuticle on the ventral surface of

the male throughout this region of the body, that is, as far forward as

the most anterior of these organs, bears about twenty exceedingly

minute structures on the ventral line, which appear to be innervated

papillae. These also stain strongly with carmine, although they are so

minute as to be difficult to observe. There are no papillae on the tail,

but there are several short hairs, more particularly near the ventrally

submedian lines. There is no bursa. The ejaculatory duct is coexten-

sive with the supplementary organs. It is on the average nearly half

I.2 mm.

FREE-LIVING FRESH-WATER NEMATODES Phy

as wide as the corresponding portion of the body. It is connected with

the seminal vesicle by a narrow portion. The seminal vesicle is elon-

gated, about half as wide as the body, and extends to a point about as

far behind the neck as the base of the neck is from the anterior ex-

tremity. From this point the two nearly equal testicles extend in oppo-

site directions, and end blind, one not far behind the base of the neck,

and the other not far from the middle of the body. These possess the

peculiarity of being slightly swollen at their proximal ends just where

they join the vesicle. These swellings appear to constitute veritable

cavities of small size. That region of the body corresponding to the

ejaculatory duct is traversed by oblique striae, which, however, are ar-

ranged at right angles to the direction of such oblique striations as

are found in other genera, and it is probable that they are connected with

the duct itself, and are not muscles of the character which usually give

rise to these oblique striations on the males of other genera. The two

equal, arcuate slender spicula appear to be of rather uniform diameter

when viewed laterally, and are one and one-half times as long as the

anal body-diameter. Their proximal ends are cephalated by contrac-

tion. They are accompanied by accessory pieces two-fifths as long as

the spicula themselves, and arranged parallel to the distal portions of

the spicula.

Habitat: Mud, about the bases of aquatic plants, Potomac river,

Dic.

MESOMERMIS, Dady.

Fig. 18, Plate VII. Fig. 24, Plate VIII.

27, Mesomermis virginiana, n.sp. oalniae RL ad aes ley 1.8 mm.

Ne, aa 2 Te 24

The rather thick, transparent, colorless layers of the naked cuticle

are destitute of transverse striations. There are minute longitudinal

striations throughout the body. These are interrupted on the lateral

lines, where there is a distinct wing. The conoid neck becomes convex-

conoid toward the lip region, which is not set off in any way. There

are no cephalic setae, and there is no distinct pharynx. The mouth

pore is very minute, and is a little toward the ventral side of the middle

of the front of the head. The cuticle has about the same thickness on

the head as elsewhere, being only a trifle thicker. The cuticle is pene-

trated on the head by a number of innervations. These end in minute

depressions on the surface of the head. Near the mouth opening there

is one of these depressions on the dorsal side, and apparently a sim-

ilar one on the ventral side, while nearer the outer. margin of the head

there are two ventrally submedian and two dorsally submedian similar

depressions. Pores occur also here and there on the body as well as

on the neck. There are no eye-spots. The lateral organs present the

118 N. A. COBB

following appearance when seen from the side: They appear to project

from the surface of the body very slightly, beginning as a tube having

a length about one-third as great as the corresponding diameter of the

head. This tube has very thin walls, and a short distance in, appar-

ently near the surface of the body, a second element appears in the

form of a circle inside that representing the contour of the outer tube.

This appears to constitute a sort of core in the midst of which are a

number of refractive elements, resembling nerve fibers, which pass in-

ward and backward toward the lumen of the oesophagus. Some of

these elements are longer than others. The focus passing inward picks

up one, then two, then several more, so that by the time a view is ob-

tained that is wholly inside the body there are seen a half dozen or

more of these elements. It is impossible in this view to pick up an in-

ternal connection of these refractive elements. The oesophagus begins

just below the transparent cuticle as a very narrow tube, probably not

more than one-eighth as wide as the corresponding portion of the neck.

It continues to have this diameter until after it passes through the nerve-

ring. At a distance from the nerve-ring equal to about one body diam-

eter, the oesophagus begins to change gradually into intestine. The

intestine gradually widens out, so that at a point as far behind the nerve-

ring as the neck is wide it has a width one-third as great as that of the

body. It goes on increasing in this way until at a distance from the

nerve ring three times as great it is two-fifths as wide as the body.

Near its middle the intestine is half as wide as the body.

The cells of the intestine contain granules of variable size, the largest

having a diameter fully twice as great as the thickness of the cuticle,

and the smallest being very minute. The female has not been seen.

The tail of the male is slightly arcuate, and is conoid to the blunt,

rounded terminus, which has a diameter half as great as that of the

base of the tail. There is no spinneret, and there are no caudal glands.

The lateral fields are about one-third as wide as the body. The nerve-

ring surrounds the oesophagus somewhat obliquely. Nothing is known

concerning the ventral glands or the excretory pore. The tail of the

male bears several series of innervated papillae. These are sufficiently

elevated at the surface of the cuticle to slightly break the contour when

the tail is seen in exact profile. Where each nerve passes through the

cuticle there is a very low, almost imperceptible elevation at the sur-

face. These papillae are arranged on the ventral submedian lines as

well as on the ventral line. The ventral papillae just in front of and

just behind the anus are double. As to particulars of the submedian

group, there are four on the tail, one member opposite the anus; one

a little farther back, a third near the middle of the tail, and a fourth

considerably farther back. In front of the anus on each side are eight

submedian papillae. These occupy a distance more than twice as great as

the length of the tail, and the distance between successive papillae in-

FREE-LIVING FRESH-WATER NEMATODES IIg

creases with the distance from the anus, so that the space between

the seventh and eighth is about two-thirds as great as the diameter

of the body. Of the median papillae on the tail there are three; two

near the anus, and one just in front of the middle of the tail, with pos-

sibly a fourth farther back. In front of the anus, of the median papillae

there are two near the anus, and ten additional ones about coextensive

with the submedian rows and distributed in the same manner, the dis-

tance between successive papillae increasing with the distance from the

anus. The two equal, arcuate, uniform, blunt spicula are about one and

one-third times as long as the anal body-diameter. Their proximal ends

are not cephalated. The ejaculatory duct is about one-third as wide as

the body. The vas deferens is about one-half as wide as the body.

There are two outstretched testicles, the blind end of the anterior being

about twice as far from the end of the neck as this latter is from the

anterior extremity. The posterior testicle is a little shorter than the

anterior.

Habitat: Cranberry bog, Arlington Farm.

ACHROMADORA, Cobb, 1914.

Fig. 11, Plate V.

28. Achromadora minima, Cobb.

For original description see Macleay Memorial Volume, Sydney,

1893; see also Journal Washington Academy of Sciences, Oct. 4, 1914,

EXPLANATION OF PLATES*

Pate II.

Fig. 1. Jota octangulare, n. sp. Lateral view of a female specimen.

a, lip region; b, labial chitinous plate or expansion; c, protruding muscles of .

the spear; d, spear; ¢, trilobed base of the spear; f, lumen of the oesophagus ;

g, nerve-ring; h, beginning of the intestine; i, flexure in the single narrow

ovary; j, excretory pore; k, ventral row of modified cuticular elements; J,

submedian row of modified cuticular elements; m, ovum; n, muscular layer;

o, anterior extremity of the uterus; p, uterus; g, cuticle; r, vulva; s, sub-

median row of modified cuticular elements; f, rectum; u, anus; v, terminus.

Fig. 2. Rhabdolaimus minor, n. sp. I, lateral view of female; II, head

of the same, showing amphid. The head in I is twisted, so that the amphid

appears as if ventral, or nearly so.

a, amphid; b, long, narrow pharynx; c, anterior group of nerve cells; d,

nerve-ring; ¢, cardiac bulb; f, wall of the intestine; g, flexure in anterior

ovary; h, posterior group of nerve cells; i, body cavity; j, lumen of intestine;

k, ovum; J, blind end of posterior ovary; m, egg; m, flexure in posterior

ovary; 0, cuticle; p, caudal glands; q, subcuticle; r, vulva; s, rectum; ¢, anus;

u, nerve cells (?); v, duct of caudal glands; w, spinneret; .r, lip region.

Fig. 3. Diplogaster fictor, Bastian. I, side view of female; II, head

of the same seen in dorso-ventral view, lips nearly closed; III, head

of the same, lateral view, lips nearly wide open; IV, head of the same,

lateral view, lips partially closed; V, front view of mouth, partially closed;

VI, lateral view, posterior portion of a male specimen; VII, somewhat dia-

grammatic perspective view showing markings of the cuticle.

a, one of the lips; 6, one of the six cephalic setae; c, amphid; d, one of

the two more or less evertible pharyngeal hook-shaped teeth; e, median

oesophageal bulb; f, nerve-ring; g, anus; h, rectum; i, intestine; j, terminus;

k, posterior oesophageal bulb; J, nerve cells; m, renette cell (?); n, left

spiculum; o, lumen of the intestine; p’, preanal male seta; p’’, p’’’,

p''’', post-anal male setae and papillae; g, one of the cells of the intestine;

r, accessory piece; s, flexure in anterior ovary; ¢, blind end of anterior ovary;

u, longitudinal striae of the cuticle; v, vagina; w, synapsis in egg in the an-

terior uterus, the reduced number of chromosomes being seven; #, one of the

spermatozoa in the ovary; y, uterus; 2, vulva.

~ ~”

*The drawings are used by permission of the Secretary of Agriculture, and were

made by Mr. W. E. Chambers, under the author’s supervision.

: OP >)

Mee oe! = X 205

Fig. 2. Rhabdolaimus minor, n. sp Fig. 3. Diplogaster fictor, Bastian.

“$00 “

PEATE 11.

PLATH si bis

Fig. 4. Prismatolaimus stenurus, n. sp. I, lateral view of a female;

II, front view of head; III, side view of head.

a, one of the six cephalic papillae; b, one of the ten cephalic setae; c,

one of the six thin lips; d, pharynx; ev, amphid; f, lumen of the oesophagus ;

g, nerve-ring; ht, cuticle; i, nucleus of ovum; 7, vulva; k, blind end of pos-

terior ovary; 1, egg; m, beginning of the intestine; 1, one of the cells of the

wall of the intestine; 0, rectum; p, anus; qg, one of the caudal glands; r, flex-

ure in anterior ovary; s, spinneret.

Fig. 5. Spilophora canadensis, n. sp. Side view of male.

a, one of the lips; b, dorsal pharyngeal tooth partly exserted; c, pharynx ;

d, base of the pharynx; ¢, lumen of the oesophagus; f, nerve cells; g, nerve-

ring; h, excretory pore; i, chitinous valve of the cardiac bulb; 7, one of the

two lateral, longitudinal rows of cuticular markings; k, lumen of the intes-

tine; /, renette cell; m, nucleus of renette cell; 1, cell accessory to the renette

cell; 0, blind end of single testis; p, point in the cuticle where the striation is

reversed; g, vas deferens; 7, one of the spicula; s, anus; ?, one of the caudal

glands; #, spinneret.

Fig. 6. Microlaimus fluviatilis, n. sp. I, lateral view of female; II,

head of the same.

a, Mouth opening; b, one of the six cephalic papillae; c, one of the four

cephalic setae; d, one of the small pharyngeal teeth; e, excretory pore; f,

spiral amphid; g, oesophagus; /t, nerve-ring; i, cardiac bulb; j, preliminary

portion of the intestine; k, renette cell; i, body cavity; m, lumen of intestine ;

n, one of the cells of the intestine; 0, anus; pf, flexure in posterior ovary; q.

uterus; r, blind end of posterior ovary; s, one of the three caudal glands; f,

spinneret; wu, eggs; v, vulva; w, cuticle.

Fig. 7. Tripyla lata, n. sp. Lateral view, male specimen.

a, cephalic seta; b, one of the three lips; c, amphid; d, spermatozoa; e,

spermatocytes in anterior testis; f, posterior extremity of the oesophagus; g,

nerve-ring; h, cuticle; 1, oesophagus; 7, lumen of oesophagus; k, intestine;

1, spermatocytes in posterior testis; m, one of the numerous ventral male

papillae; n, vas deferens; o, retractory muscle of spiculum; p, one of the

spicula; g, lumen of the intestine; r, duct of one of the caudal glands; s,

caudal gland; ¢, spinneret.

Fig. 4. Prismatolaimus Fig. 5. Spilophora canadensis, n. sp.

stenurus, n.°sp.

PON A lll :

(am 6

x 100

a || ————F

“ig, a Microlaimus fluviatilis, n. sp. Migs. i ripyia lata, «sp:

Prate*l it.

PLATES.

Fig. 8. Teratocephalus cornutus, n. sp. I, lateral view of a female; II,

lateral view of head, more highly magnified; III, front view of head; IV,

dorso-ventral view showing lips wide open; V, cuticle showing lateral field.

a, one of the six movable, chitinous lips; 0, one of the four submedian

cephalic setae; c, amphid; d, nerve-ring; e, excretory pore; f, organ of un-

known significance; g, cardiac bulb; h, intestine; 7, anus; j, rectum; k, cu-

ticle; J, one of the cells of the intestine; m, lumen of the intestine; mn, flex-

ures in ovary; 0, egg; P, vulva; g, blind end of posterior ovary; ™, terminus.

Fig. 9. Alaimus simplex, n. sp. I, lateral view of a female; II, an-

terior extremity, lateral view; III, posterior extremity of a male, lateral view.

a, lip region; b, pharynx; c, amphid; d, amphid, enlarged; e¢, group of

spermatozoa at the posterior portion of the ovary; f, blind end of ovary;

g, male supplementary papillae; 1, left spiculum; 1, terminus; 7, rudimentary

submedian elevation or flap of the cuticle, indicating rudimentary bursa; k,

egg; 1, vulva; m, nerve-ring; 1, posterior extremity of oesophagus; p, modi-

fied cells of anterior portion of the intestine; q, cuticle; r, wall of the in-

testine; s, lumen of the intestine; t, flexure in the single ovary.

Fig. 10. Plectus tubifer, n. sp. Male specimen, lateral view.

a, lips; b, papilla-like cephalic seta; c, amphid; d, anterior chamber of

pharynx; e, posterior chamber of pharynx; f, lumen of the oesophagus; g,

nerve-ring; h, excretory pore; i, renette cell; 7, cardiac bulb; k, vulva of

cardiac bulb; 1, cardia; m, lumen of intestine; , blind end of anterior testis;

0, spermatocyte; p, junction of testes; g, blind end of posterior testis; 7, be-

- ginning of vas deferens; s, spermatozoon; t, male glands; uw, one of the cau-

dal glands; v, anterior of the three tubular supplementary organs; w, spicula ;

x, anus; y, one of the nine male papillae; 2, spinneret.

mus simplex, n.

Peratocephalus

cornutus,

Plectus iubifer, n. sp.

PLATE IV.

Pag 0:

PLATE V.

Fig. 11. Achromadora minima, Cobb. I, lateral view of a female; II,

lateral view showing cuticular markings; II], lateral view of head.

a, cephalic papilla; b, cephalic seta; c, one of the ribs of the pharynx;

d, dorsal pharyngeal tooth; e, sub-ventral (?) pharyngeal tooth; f, pharynx;

g, cuticular markings; , amphid; i, nerve cell; 7, nerve-ring; k, spinneret;

l, excretory pore; m, flexure of ovary; m, one of the caudal glands; o, blind

end of posterior ovary; p, anus; gq, intestine; 7, vulva; s, one of the gran-

ules of the intestine; f, egg.

Fig. 12. Dorylaimus fecundus, n. sp. Side view of head and tail of

female, and tail of male.

a, spear or onchus; b, one of the six anterior cephalic papillae; c, one

of the six posterior cephalic papillae; d, guiding ring of the spear; e, oeso-

phagus; f, intestine; g, rectum; /, anus; i, one of the anal muscles; j, one of

the four lateral caudal, innervated papillae; k, cuticle; J, subcuticle; m, mus-

cular layer; 1, wall of the intestine; 0, one of the numerous oblique ejacu-

latory muscles; p, one of the numerous ventral male papillae; q, ejaculatory

duct; r, one of the two preanal papillae; s, retractor muscle of one of the

spicula; ¢, muscular layer; u, right spiculum; v, right accessory piece.

Fig. 13. Jronus americanus, n. sp. I, anterior extremity, lateral view,

oral organs everted: II, same, more highly magnified; III, anterior extremity

of a specimen about to moult, showing two sets of oral organs, the anterior

set in process of being replaced by the posterior; IV, posterior extremity of

a female, lateral view.

a, one of the three chitinous oral teeth; b, cephalic papilla; c, cephalic

seta; d, amphid; e, pharynx; f, anterior group of minute pharyngeal teeth;

g, posterior group of pharyngeal teeth; /, oesophagus; i, lining of oesopha-

gus; 7, nerve-ring; k, intestine; /, anus; m, base of the tail; , terminus.

Fig. 14. Oncholaimus punctatus, n. sp. Lateral view of head and tail

of male specimen.

a, terminal flaps of lips; b, lip; c, cephalic papilla; d, one of the papilla-

like cephalic setae; e, right submedian onchus; f, left submedian onchus; g,

wall of pharynx; h, intestine; i, ejaculatory duct; j, one of the spicula; k,

dorsal onchus; /, amphid; m, duct of oesophageal gland leading into onchus ;

n, rectum; o, beginning of the oesophagus; p, anus; gq, lining of the oesopha-

gus; r, one of the caudal glands; s, one of the two male papillae; ¢, ducts of

the caudal glands; u, spinneret.

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nenonoodal

n. sp.

fecundus

Dorylaimus

b2.

Fig.

Cobb

Achramadora minima,

ies

Fig.

SSS

PERN

MA ELT.

SEPHA,

Tigress

x457

Peittrvsew ohn eae es

Oncholaimus punctatus, n.

sp.

~T4.

Tees. Tig.

s americanus,

Tronu

[ge

PLATE V.

Piate VI.

Fig. 15. Trilobus longus, (Leidy), Bastian. I, male specimen, lateral

view; II and III, head of the same, lateral view; IV, head, dorso-ventral

view; V, VI, and VII, enlarged views of the ventral supplementary organs.

a, lateral cephalic seta; b, cephalic papilla; c, submedian cephalic setae;

d, pharynx; ¢, amphid; f, anterior pharyngeal tooth; g, posterior pharyngeal

tooth; h, oesophagus; i, nerve-ring; 7, excretory pore; k, nerve cells; / gland-

ular (?) organs; m, lumen of intestine; », blind end of anterior testis; 0,

testis; p, junction of testes; q, blind end of posterior testis; r, vas deferens;

s, anterior male supplementary organ of the anterior series; f, anterior sup- .

plementary organ of the posterior series; u, spicula; z, accessory piece; w,

caudal gland; x, anus; y, terminus; z, nerve ending of papilla of the supple-

mentary organ.

Fig. 16. Dolichodorus heterocephalus, n. g., n. sp. I, nearly side view of a

female; II, lateral view of surface of head, more highly enlarged; III, sagit-

tal section of head; IV, dorso-ventral view of head; V, front view of head;

VI, side view, posterior extremity of male; VII, ventral view of posterior

extremity of female; VIII, ventral view of posterior extremity of male.

a, papilla; b, cephalic organ of unknown significance; c, spear; d, base of

spear; e, median bulb; f, nerve-ring; g, excretory pore; h, cardiac swelling;

i, intestine; 7, anus; k, lateral caudal pores; 1, terminus; m, blind end of pos-

terior ovary; n, ovary; o, left spiculum; p, accessory piece; g, distal end of

accessory piece; 7, left flap of bursa; s, terminus of male; ¢, ovum; u, sper-

matozoa; v, vaginal muscles; w, uterus; +, vulva; y, anus.

Fig. 17. Cyatholaimus truncatus, n. sp. I, side view of a female; II, side

view of head; III, front view of the same head; IV, ventral view of anal

region of male; V, lateral view of the same; VI, lateral view in the middle

of the body showing cuticular markings and pores.

a, submedian cephalic seta; b, labial papillae; c, amphid; d, dorsal tooth;

e, lateral cephalic seta; f, one of the twelve ribs of the vestibule; g, small

submedian pharyngeal tooth; h, base of the pharynx; i, ejaculatory duct; 1,

intestine; k, one of the four male pre-anal supplementary organs; /, one of

the spicula; m, anal muscles; nm, one of the accessory pieces; 0, nerve-ring ;

p, one of the cells of the intestine; g, lumen of the intestine; r, anus; s, blind

end of reflexed ovary; ¢, egg; u, vulva; v, flexure in anterior ovary; w,

junction of the ovary and uterus; x, pores in the cuticle; y, one of the three

caudal glands; z, male gland (?).

longus, (Leidy), Bastian

Fig. 16. Dolichodorus heterocephalus, Fig. 17. Cyatholaimus truncatus, n. sp.

n. 24 N, sp. PLATE VI.

PEATE Vil:

Fig. 18. Mesomermis virginiana, n. sp. Lateral view of head and tail.

a mouth opening; b, one of the anterior rows of cephalic papillae; c,

one of the posterior row of cephalic papillae; d, pharynx; e, exterior of am-

phid; f, interior of amphid; g, oesophagus; /, innervated papilla; 7, gland-

ular cephalic organs: j, nerve-ring; k, lumen of oesophagus; /, intestine; #1,

e,aculatory duct; 1, body cavity; 0, oblique copulatory muscles; p, one of the

submedian supplementary organs; g, one of the median supplementary or-

gans; 7, spicula; s, one of the median post-anal supplementary organs; f,

final submedian supplementary organs; u, submedian supplementary organ.

Tig. 19. Ethmolaimus americanus, n. sp. Lateral view of a female.

a, lips; b, minute dorsal and ventral pharyngeal teeth; c, one of the

four cephalic setae; d, amphid; ¢, pharynx; f, nerve-ring; g, excretory pore;

h, nerve cells; 7%, cardiac bulb; 7, beginning of the intestine; k, renette

cell (?); J, beginning of main portion of the intestine; m, one of two

pairs of unicellular organs of unknown significance; 1, cuticle; 0, one of the

cells of the intestine; p, subcuticle; g and r, body cavity; s, vulva; ¢, nuclei

of one of the muscle cells; u, spinneret; v, one of the caudal glands; w, anus.

Fig. 20. Monhystera sentiens, n. sp. I, side view of a female; II, side

view of head of the same; III, side view of posterior extremity of a male.

a, pharynx; b, submedian cephalic seta; c, lateral cephalic seta; d, sper-

inatozoon; e, amphid; f, lining of oesophagus; g, oesophagus; /1, subcephalic

setae; 7, lumen of intestine; /, nerve cells; k, nerve-ring; /, striated lip re-

gion; mm, left spiculum; n, glandular structure associated with amphid; o,

blind end of single ovary; pp, the three caudal glands; qg, anal muscles; r,

spinneret: s, beginning of intestine; f, anus; u, one of the cells composing

the intestine; v, vulva; w, egg, the spermatozoa “d” being outside of the egg

“w''; x, egg in synapsis; y, vaginal glands; z, ovum.

Fig. 21. Oncholaimellus heterurus, n. sp. I, side view of head; II, ven-

tral view of head; III, side view of tail end of male; IV, ventral view of

anal region of male.

a, excretory pore; b, submedian cephalic seta; c, pharynx; d, left flap

of bursa; e, oesophagus; f, left spiculum; g, accessory piece; h, amphid; 1,

male post-anal seta and papilla; 7, lateral seta; k, spinneret; /, thin lips.

“

eae

Fig. 18. Mesomermis virginiana, n. sp.

Fy ad

Fig. 19. Ethmolaimus

americanus, n. sp.

«298

Fig. 20. Monhystera sentiens, n. sp. Fig. 21. Oncholaimellus heterurus,

) PrAtEs Vik tim SP.

PoATe.V LU

Fig. 22. Cephalobus sub-elongatus, n. sp. Lateral view of a female.

a, lips; b, pharynx; c, anterior portion of oesophagus; d, posterior ex-

tremity of anterior portion of oesophagus; e, nerve-ring; f, cardiac bulb; g,

beginning of intestine; 1, one of the cells of the intestine; 7, lumen of the

intestine; j, excretory pore; k, cardiac valve; J, renette cell; m, flexure in

single ovary; , cuticle; 0, ovary; p, spermatozoon in uterus; gq, vulva; r,

nucleus in ovum; s, body cavity; ¢, anus; u, ripe ovum; v, unripe ovum; w,

oocyte; +, blind end of ovary; y, rectum; 2, terminus.

Fig. 23. Bastiana exilis, n. sp. Lateral view of a male specimen.

a, one of the six cephalic papillae; b, one of the posterior set of four

submedian cephalic setae; c, one of the anterior set of six cephalic setae; d,

oesophagus; e, cervical seta; f, amphid; g, one of the cells of the intestine;

h, one of the numerous male supplementary organs; i, blind end of the two

testes; j, nerve-ring; k, posterior extremity of oesophagus, (pseudo-bulb) ;

l, left spiculum; m, cuticle; n, spermatozoon; o, anal muscle; p, treminus; q,

vas deferens; 7, intestine.

Fig. 25. Aphanolaimus spiriferus, n. sp. I, lateral view, anterior ex-

tremity of a female; II, lateral view, posterior extremity of a female; III,

lateral view of head, more highly magnified; IV, one of the male supple-

mentary organs; V, lateral view of posterior extremity of male.

a, mouth opening; b, amphid; c, lumen of oesophagus; d, pigmented eye-

spot (?); e, intestine; f, nerve-cell; g, rectum; h, nerve-ring; i, anus; k,

oesophagus; /, caudal gland; m, duct of one of the caudal glands; n, gland-

ular body at base of neck; 0, spinneret; pf, ejaculatory duct; g, intestine; r,

anterior end of cloaca; s, right spiculum; f, backward pointing accessory

piece; u, nerve-cells (?) ; v, one of the numerous male supplementary organs.

Cephalobus

subelongatus,

n. sp.

G re

Fig. 24. Mesomermis virginiana, n. sp. Fig. 25.

PLATE AY

“be

or ae Ce nw 6

ome A.4

a omg spe ME

p Rea

ae = 5950

Fig. 23. . Bastiana exilis, n. sp.

Ss ‘ a“

Alphanolaimus spiriferus, n. sp.

DEPARTMENT OF NOTES, REVIEWS, ETC.

It is the purpose, in this department, to present from time to time brief original

notes, both of methods of work and of results, by members of the Society. All

members are invited to submit such items. In the absence of these there will be given a

few brief abstracts of recent work of more general interest to students and teachers.

There will be no attempt to make these abstracts exhaustive. They will illustrate progress

without attempting to define it, and will thus give to the teacher current illustrations, and

to the isolated student suggestions of suitable fields of investigation.—[Editor. ]

FURTHER NOTES ON PRISTINA WITH DESCRIPTIONS OF THREE NEW

SPECIES.

This note is supplementary to the one that appeared in Science

for October 18, 1912, vol. XXXVI., no. 929, p. 530. Two of the

species described below were found in pools near Charlottesville,

Va., while the third was found in an aquarium in the zoological

laboratory of the Agricultural and Mechanical College of Texas.

This last species, Pristina antenniseta, is remarkable for the fact

that the sex organs are well developed at a time when the animal is

actively engaged in the process of fission. The sex organs seem to

be slightly different in their location from those described in P. leidyi.

An unfortunate error in the previous note should be corrected

here. The length of Pristina variabilis averages about 1. 5 mm, in-

steam of 8 microns as there given, an obvious error to any one

familiar with the Naididae.

The following species of Naids were found in the aquaria of

the University of Virginia, which had been filled from several ponds

in the vicinity of the University and Charlottesville.

Chaetogaster langi Bretscher 1896,

Dero limosa Leidy 1852,

Nats parviseta Walton 1906,

Pristina variabilis n. sp.,

Pristina tangiseta n. sp.,

The following species of Naids were found in the aquaria of

the Agricultural and Mechanical College of Texas, which had been

filled from watering troughs and small ponds in the vicinity :

Dero vaga (Leidy 1880) L. Vaillant 1890,

Pristina antenniseta n. sp.

136 NOTES, REVIEWS, ETC.

The three new species just mentioned are here described:

Pristina variabilis n. sp.

Prostomium with a tentacular process of varying length. Dor-

sal setae of two kinds: (1) capilliform, those of segment 2 about .

one-half, and of segment 3 about three-fourths as long as those of

the following segments; and (2) short straight needle-like setae,

bifid, with teeth unequal. Ventral bundles with four to eight biun-

cinate setae.

First nephridia in segment 9. Ccelomic corpuscles black. Bud-

ding takes place after segment 15. Length about 1.5 mm. Number

of segments about 30.

Reproductive organs not observed.

In ponds, etc. Virginia (Charlottesville).

This species differs from Pristina (Naidium) breviseta in

length (P. breviseta, with its length of 8 mm. is a giant in com-

parison) and in the length of the tentacular process, which is well

developed. This species meets the requirements made by Walton

(American Naturalist, vol. XL., 1906, p. 705) who says:

“The absence of any tentacular process in Naidium osborm

suggests that until a species is found in which the process is well

developed and in which the dorsal bundles contain biuncinate setae,

the genera may be considered distinct.”

As I said in speaking of this species (Science, loc. cit.), it has

both these requirements and therefore serves as a link between

Pristina Ehrenberg and Naidium Schmidt, confirming Micheelsen’s

combination of them in 1909 (Die Stisswasserfauna Deutschlands,

Heft 13, p. 25).

The species is named from the varying length of the tentacular

process.

Pristina tangiseta n. sp.

Prostomium with a long tentacular process. Ventral bundles

of setae with typically four bifid setae, the distal teeth longer than

the proximal teeth. Dorsal setae serrated on the convex edge, and

usually two to the bundle, one about 200 microns long and the other

much shorter. On segment 3, the dorsal setae are much longer,

from 400 to 600 microns, and have a motion independent of the

AMERICAN MICROSCOPICAL SOCIETY 137

others. Their usual forward position suggests that they may be

used as tactile organs, and for this reason I have suggested the

specific name tangiseta.

First nephridia in segment 9. Glandular “stomach” in segment

8. Budding takes place after segment 25. Length 5 to 8 mm.

Reproductive organs not observed.

This form is much like P. leidyi, except that the dorsal setae

are over six times as long as those of the latter, and the ventral

setae of segment 6 are not modified as sexual setae, though it may

be that these are only so modified during the period of sexual

maturity.

In ponds, etc. Virginia (Charlottesville).

Pristina antenniseta n. sp.

Prostomium with a tentacular process as long as 450 microns,

about 225 microns long at the moment of fission. Ventral bundles

with 3 to 5 bifid setae, the distal teeth longer than the proximal

teeth. Dorsal setae begin on segment 2. With the exception of

segment 3, the dorsal bundles contain two convexly serrated capilli-

form setae from 200 to 450 microns in:length, and from 2 to 4

needle-like setae, 60 to 75 microns long. The dorsal capilliform

setae of segment 3 are both smooth, from 400 to 750 microns long,

and usually point forwards as in P. tangiseta, hence the specific

name.

First nephridia in segment 9. Glandular “stomach” in seg-

ment 8. Transverse vessels in segments 1 to 8, Coelomic corpuscles

greenish black. Budding takes place after segment 14. Length of

full-grown individuals before beginning of fission 3 to 5 mm. Num-

_ ber of segments under similar circumstances about 28.

Testes and spermothecae in segment 6. Ovaries in segment 7.

Seminal vesicles in segment 5.

This form is somewhat like P. tangiseta, except that there are

no serrated setae in the dorsal bundles of segment 3, and that bud-

ding takes place usually after segment 14, 15, or 16, whereas in P.

tangiseta it never takes place before segment 25.

P. antenmseta presents the rather rare condition of sexual ma-

turity during the period of active fission. The sex organs will be

138 NOTES, REVIEWS, ETC.

described in a later paper. This species is also rather variable in

length. One individual was found which had a length of 7 mm.,

and was dividing in two places, behind the 22nd and the 36th seg-

ments. .

In ponds, etc. Texas (College Station).

A. and M. College, Texas. Horace Epwin Haypen, Jr.

A NEMATODE PARASITE OF THE ALLIGATOR.

While dissecting an eighteen-inch Florida Alligator a curious

swelling was noticed on the outside of the larger chamber of the

stomach. On opening this swelling it was found to contain a small,

coiled worm. The worm was sent to Dr. Edwin Linton for identifi-

cation and proved to be, so far as could be determined, an immature

specimen of Ascaris tenuicollis Rudolphi.

The worm had been hardened in formalin before it was dis-

covered, so that it could not be uncoiled, but it was about 75 mm.

in length.

Figure 1 shows the stomach of the alligator with the worm, n,

in the capsule, but with the outer covering removed. This figure is

about life size.

Figure 2 shows the worm after removal from the capsule,

enlarged several times. Both figures are from photographs.

ALBERT M. REESE.

Dept. of Zoology, West Virginia University.

BEHAVIOR OF PIGMENT CELLS IN LARVAE OF AMPHIBIANS,

Holmes (U. of Cal. Pub. Zool. Sept., 1913) has studied the

pigment cells of Hyla regilla in hanging drop cultures of small

pieces of the larvae. He was thus enabled to see both the outlines

of the cells and the position of the pigment. In their natural posi-

tion in the tissues it is practicaily impossible to see the actual out-

lines of the cells. In the hanging drop cultures the pigment cells

may wander away from the rest of the tissue and become entirely

isolated. These chromatophores differed widely in shape, and the

individual cells changed shape readily, much after the manner of the

Ameba. There is a thin layer of transparent ectoplasm behaving

much like that in the Ameba. The endoplasm contains the pigment

granules, varying greatly in amount.

Fig. 1. The stomach of a Florida Alligator of 18 inches length, natural size.

n, nematode worm lying in its capsule in the wall of the larger chamber of the

stomach; e, opening from the oesophagus: v, opening between the larger and smaller

chambers of the stomach; p, the pyloric vab between the smaller chamber and_ the

du ce Num.

ig. 2. A photomicrograph of the worm after removal from the capsule.

PLATE LX

AMERICAN MICROSCOPICAL SOCIETY 139

The author makes it clear that the pigment cells in the larvae

of Hyla change their form, and thus the distribution of pigment in

the skin. He feels that these cell processes may become more fixed

in the adult, and that the changes in the distribution of pigment may

pe rather due to migration of the endoplasm carrying the granules

along these fixed branches as many students have held. It is unsafe

however to deny that they may still retain some ameboid powers of

change of form even in the adult.

BEHAVIOR OF ECTODERMIC EPITHELIUM.

Holmes (U. of Cal. Pub. Zool. Sept. 1913) gives an account of

the study of epithelial cells in vitro, which supports the view that

the movements of the epithelium known to take place in the healing

of wounds are aided by active pseudopodial growths. He found

that pieces of larvae cultivated in plasma send out strands of ecto-

dermal cells into the plasma; that these tend to extend upon solid

surfaces; that isolated epithelial cells tend to spread out and to

creep along such surfaces; that such scattered cells may unite into

a continuous membrane; that these cells have a thin, clear ecto-

plasm which puts forth pseudopodia. He believes these pseudopodia

are actively engaged in these migrations of cells. Healing of wounds

and restoration of the epithelium is not due then primarily to cell

division of cells already at the edges; but much more to active

migration, fusion, and spreading of suitable cells.

CROSS INOCULATION OF LEGUMES.

Ewart and Thomson (Proc. R. S. Victoria, Mch. 1913) under-

took to determine whether bacteria from the root nodules of native

Victorian legumes were able directly to infect the cultivated legu-

minose plants not native to Victoria. The results were negative.

The authors suggest that the parasitic bacteria of particular root

nodules are biologically adapted to the conditions in the host plant,

and cannot directly adapt themselves to a new host plant.

It was found possible to infect peas and beans with bacteria

from acacia tubercles, after these had been isolated and cultivated

on nutrient gelatin. The conclusion is that the parasitic bacteria,

when placed in sterile soil or in non-living media, become more gen-

140 NOTES, REVIEWS, ETC.

eralized in power from the saprophytic life and thus step by step

become able to infect species farther and farther removed from the

original host.

THE BINOCULAR MICROSCOPE.

Felix Jentzsch and Conrad Beck (J. R. M. S. Feb. 1914) pre-

sent two illuminating articles on the binocular microscope, its past

and present. In these papers the binoculars are compared with the

monocular as to their effects, and the various types of binoculars

are compared and their mechanical structure illustrated. There are

three types of binoculars :—

1. Those in which the light from a single objective is geo-

metrically divided, one half going to each eye. The beam of light is

itself bisected. Tach eye receives all the light from one-half the field.

2. Those in which the pencils of light from every part of one

objective field are split, by one device or another, so that a part of

each pencil goes into each eye. Thus each eye receives one-half the

light from the whole field. In some of the later instruments this

sifting or filtering of the light- is secured by a half-silvered film

which transmits half the light directly, and reflects the other half

so that it may be carried to the other eye.

3. Those in which there are two complete monocular micro-

scopes pointed obliquely at the same object. This is useful for low

powers only.

The advantages claimed for the newer binoculars of the second

class are (1) distinct hygienic value due to less fatigue; (2) a sum-

mation of stimuli in both eyes resulting in “vividity”; (3) a certain

enhancement of impression due to parallectic effect.

THE JOURNAL OF MICROLOGY.

As an offshoot of the activities of the Postal Microscopical

Club, the Secretary, Mr. H. Edwards, is issuing a monthly journal

with the above title. It is intended to serve the interests of the ama-

teur and spare-time worker, who finds little to meet his needs in

the technical journals. Its space is given to brief articles on simple

organisms, to discussions of microscopes and accessories, to methods

of mounting microscopic objects, and to queries and answers. There

seems to be promise in it of great helpfulness and inspiration to the

AMERICAN MICROSCOPICAL SOCIETY I4!

isolated amateur worker. The price is merely nominal,—3 s. 6 d.

yearly. Address the Secretary, 22 Carnarvon Road, Reading, Eng-

land.

THE LIFE-CYCLE IN HYPOTRICHOUS INFUSORIA.

Baitsell (J. Exp. Zool. Feb. 1914) has undertaken to determine

whether culture conditions could be found for Oxytricha and Pleu-

rotricha that would eliminate the so-called life-cycle, which assumes

the necessity of conjugation to prevent senescence and death as the

result of continued division. He concludes that the dying out of

some cultures was due, not to a condition of inherent senescence but

to the fact that the culture conditions were not entirely favorable.

He found that “sister cells” of Oxytricha lived twice as long in mass

cultures without conjugation as when bred in daily isolation cul-

tures. In Pleurotricha he has found culture conditions in which the

organism will apparently live indefinitely without conjugation or

artificial stimulation—as Woodruff has earlier found for Parame-

cium.

In the same journal Woodruff has a note showing that his race

of Paramecium which had gone for 4102 generations without ten-

dency to conjugate presented numerous conjugating pairs. This dis-

poses of the idea that non-conjugating races of Paramecium have

been isolated.

PEARL FORMATION.

Fr. Alverdes (Zeits. Wiss. Zool. CV., 1913, p. 598) discusses

the formation and structure of pearls in several pearl-bearing mol-

lusks. The pearl forming layer is ectodermal, but the origin of the

sac is uncertain. By inserting ectoderm cells in the mantle tissues

sacs similar to the usual pearl-sacs were formed, and in these the

pearly layers were deposited. The author found that pearls may

or may not have a central foreign body or nucleus, The pearl may

be laid down around a parasite, an ovum, or a fragment of inor-

ganic matter. These foreign bodies may produce a kind of pseudo-

sac in which the pearl may be laid down in concentric layers.

REGENERATION OF NERVES.

Clark (Jour. Comp. Neur. Feb. 1914) attacks in a new way

the questions clustering about degenerating and regenerating nerves.

142 : NOTES, REVIEWS, ETC.

owls by prolonged feeding with polished rice undergo progressive

degeneration of medullated nerve fibres. This shows as progressive

paralysis. These nerves regenerate with adequate diet. The nerve

fibres are intact during the whole time; there are no wounds or in-

flammations; and no inwandering fibres from other nerves. The

writer secured degeneration and regeneration without any trace of

multiplication of the nuclei of the neurilemma sheath which has

been interpreted by many to mean the formation of embryonic nerve

fibres and auto-regeneration.

By prolonging the degenerative process the writer secured in-

stances of multiplication of the nuclei in sheath. He believes that

the so called embryonic fibres are degenerative phenomena, and not

regenerative. In total absence of “embryonic nerve fibres” new axis

cylinders grew peripherally down the old medullary sheath, passing

alongside remnants of the old axis within the sheath.

BEHAVIOR OF NUCLEUS IN CRYSTAL-FORMATION.

Samuels (Compt. Rend. CLVI, 1913, p. 1275) gives an account

of his studies of the behavior of cells in the bracts of Anthurium

during the formation of crystals. Two kinds of crystals are present:

polyhedral crystals which are abundant in the outer cells, and rap-

hides which are found more sparingly and in the deeper cells. In

the case of the polyhedral crystals the nucleus retreats to one side

of the cell in the densest protoplasm. Striations later pass from the

nucleus to the crystals. When the crystals are formed the nucleus

is destroyed. A similar fate awaits the nuclei of cells in which the

raphides form. In this case however several cells may lose their

walls and their nuclei fuse into one. From this the raphides diverge.

ENTOMOLOGICAL NOTES.

A new family of Orthoptera.—Walker (’14, Can. Ent., 46 :93-

99) reports the finding of specimens on Sulphur Mountain, Banff,

Alberta, which represent a new family of the order Orthoptera.

The insects are placed without hesitancy in this order since the

characters of the mouth-parts, cervical and thoracic sclerites, and

ovipositor are distinctly orthopteran. They are wingless, thysanuri-

form insects of a very generalized type and the discovery of these

AMERICAN MICROSCOPICAL SOCIETY 143

unique forms throws additional light upon the phylogeny of the

order. Grylloblattide, the new family, combines the characters of

several different orthopterous families but is distinct from all of

them. It seems to be most nearly related to the Blattidze although

in some respects it resembles the Forficulide. The Ovipositor is re-

garded as a significant structure, representing closely, in Gryllo-

blattidze, the same organ in the common ancestor of the three fami-

lies of saltorial Orthoptera, the Tettigonide having departed least

from the original type as regards this organ. Grylloblattide have

been derived from some primitive type of blattid or blattid-like

ancestor. These new insects have been named Grylloblatta campo-

deiformis, n. gen. et n. sp.

Inheritance and Evolution in Orthoptera.—Nabours (’14,

Journ. Genetics, 3:141-170) in a paper entitled “Studies of Inheri-

tance and Evolution in Orthoptera” reports the results of an ex-

tended study on the genus Paratettix. The inheritance behavior of

the color patterns shows the Mendelian type of inheritance. The

great majority of the hybrid patterns show in the visible somatic

constitution “all the parts which can be distinguished in the somatic

make-up of each of their parent patterns.” These grasshoppers

show no characters which by crossing can be replaced by other

characters but the whole pattern appears to behave as a single unit.

Definite variations in the length of wings and pronota are not in-

heritable but are considered as somatic, resulting from differences in

environmental conditions. Protracted conditions conducive to slow

growth result in a preponderance of short winged individuals ; oppo-

site conditions result in a preponderance of long winged forms. It

is suggested that variations in the amount of sunshine in different

seasons may account for this form of dimorphism and polymor-

phism. A large plate in natural colors illustrates many of the points

of the paper in a striking way. Nine pure strains and eighteen

hybrids resulting from crosses of the former are illustrated.

Distribution of Collembola.—Bacon (’14, Journ. Ent. and Zool.,

6:45-57) adds interesting data on the distribution of certain Col-

lembola. Neapura gigantea Tull, a very large species which hereto-

fore has been known only from St. Paul Island in the Bering Sea,

Northern Siberia, and from the vicinity of St. Lawrence Bay, has

144 NOTES, REVIEWS, ETC.

been found in moderate abundance in the vicinity of Claremont,

California. It would appear that this species has a very wide dis-

- tribution.

Cecal Bacteria and their role-—Glasgow (’14, Biological Bul-

letin, 26:101-170) has published a very important and interesting

paper on “The Gastric Ceca and the Czcal Bacteria of the Heterop-

tera.” In certain groups of the Heteroptera the digestive tract is

characterized by the presence of peculiar sac-like appendages which

are associated with the mid-intestine at its posterior end. These

organs vary greatly in form, size, shape, number, and distribution

in the different families but the histological structure is the same

and invariably contain conspicuous masses of bacteria which have

been found to be characteristic for families and frequently for the

genera in which they occur. Gastric ceca were noted as early as

1809 but cecal bacteria were not discovered until 1882 when Pro-

fessor S. A. Forbes found them in the chinch bug, Blissus leucop-

terus. An examination of a very large number of specimens of

Murgantia historionica from localities ranging from Maryland to

California and from the Gulf States to Hlinois showed that the

bacteria in the ceca of this species are invariably identical. It was

found that bacteria are not always present in the ceca of normal

bugs. Jt was also found that infection takes place through the egg,

the organisms appearing early in the digestive tract of the embryo.

Work on the cultivation of these cecal organisms showed that they

are true bacteria. Critical microscopical examinations of the czcal

bacteria showed that structurally they differ greatly in different

hosts “ranging from minute, coccus-like bacteria measuring often

less than one micron, to huge, spirochete-like forms thirty microns

or more in length; but in whatever form they occur they are mor-

phologically characteristic for the particular species harboring them.”

Studies on the functional relation of the cecal bacteria to the host

insect and the importance of the normal intestinal bacteria to the

host showed that the czecal bacteria appear to have the power of in-

hibiting the development of foreign bacteria as well as excluding

them altogether. The mid-intestine, which, in many related forms,

contains numerous foreign bacteria and protozoa, is free of the lat-

ter in species having czcal bacteria. About ninety species of Heter-

AMERICAN MICROSCOPICAL SOCIETY 145

optera distributed among twenty-one families were studied in this

connection and it was found that the cecal appendages are appar-

ently of profound phylogenetic significance. They show a “com-

plete gradation from extremely simple to very complex forms and

in many cases indicate relationships contrary to those often assumed

in the arrangement of groups.”’

Genera of Noctuide—W. T. M. Forbes (’14, Journ. N. Y.

Ent. Soc. 22:1-33) has published a useful paper entitled “A Table

of the Genera of Noctuide of Northeastern North America.” The

last general review of the Noctuide of this country was published

by J. B. Smith in the Bulletin of the Brooklyn Entomological So-

ciety in 1882 and is now quite out of date. Although the table is

restricted to the genera of a limited portion of this country, it will

doubtless be of considerable service to those interested in Lepi-

doptera and especially to those who do not have access to the exten-

sive works on this order, such as Hampson’s Catalogue of the Lepi-

doptera Phalznz in the British Museum.

“Aerostatic hairs” in lepidopterous larvae.—Riley (13, Science,

37 :715-716) reports the results of a study of the so-called aerostatic

hairs of certain lepidopterous larvae. These hairs are found on cer-

tain larval stages of the gypsy moth and the nun moth and are

characterized by globular swellings at the base. As indicated by

the name it was originally supposed that these swellings were air

reservoirs and that they function as a collection of tiny balloons and

played a rdéle aiding the dispersal of the species by the wind. It has

been shown that the assumption that these swellings are filled with

air is erroneous and that instead they are filled with fluid which

is very probably poisonous and may serve to protect the larve

against insectivorous birds. Sections showed a large unicellular

gland underlying each so-called aerostatic bristle and opening di-

rectly into the cavity. Detailed study also showed that these glands

are distinct from the trichogens, the enlarged hypodermal cells which

give rise to the hairs. It thus seems that these hairs do not function

in “rendering the larve more buoyant but are really toxophores.”

Paut S. WELCH.

146 NOTES, REVIEWS, ETC.

NOTES ON HISTOLOGY AND TECHNIC.

Two new washing devices—New devices for the washing of

histological tissues and slides are brought forward from time to

time which are but modifications of existing devices. Two new

devices of exceptional merit are suggested by Dr. R. M. Strong in

Anat. Record, 8:27-31. An apparatus for washing histological tis-

sues consists of a shelf over a sink on which rests a shallow box

with a shield at the back. The box measures 82x5x30 cms. It has

an outlet to the sink below. Above the box is a series of six brass

pet-cocks connected with the water supply. Five of these have five-

branched outlets. Under these bottles or jars with tissues may be

washed. The sixth pet-cock discharges directly over a washing

apparatus for microscopic slides. This device is especially desirable

in laboratories in which it is necessary to augment the amount of

sink room and the number of taps to meet the needs of a large class.

The device for washing slides consists of a dish made by solder-

ing two circles of corrugated galvanized iron to a circular galvan-

ized iron bottom. The two circles have a diameter of 734 and 534

inches respectively, leaving just room enough for a 1x3 inch slide

between them. The height of the outer wall is 2 inches, of the inner

wall 134 inches. Water is discharged to the inner chamber, then it

flows over the inner wall and overflows the outer wall. To wash

slides uniformly it is necessary that the device be placed on a level

surface. The device figured by Strong holds 112 slides if placed

back to back. |

New lens-carrier for laboratory microscope-——A small acces-

sory fitting of great convenience for the laboratory microscope has

been brought out by the Spencer Lens Co. during the past year.

This consists of a short straight arm attached at one end to the

lower side of the stage. The free end of the arm has the form of a

ring which carries the extra ocular. The arm with the ocular swings

under the stage out of sight and out of the way. The great advan-

tage of this lens-arm is that the extra lens is always at hand for use.

There is moreover very little reason for ocular equipment of the

microscopes at a laboratory table being mixed up, while under the

old scheme of using a loose lens-block there was always hopeless

confusion of ocular equipment.

AMERICAN MICROSCOPICAL SOCIETY 147

Improved arc lamp for projection—Users of projection lan-

terns will be interested in learning of a recent improvement in the

arc-lamp. This consists in the placing in the circuit of a pair of

coils of heavy copper wire, one on either side of the arc at a dis-

tance of about 1% inches. The current passing thru the coils cre-

ates two magnetic fields which serve to control the arc. By the use

of this device sputtering is largely done away with and the position

of the crater remains nearly constant. A lamp so equipped requires

less frequent attention than does the old style. In a recent trial of

this device when using about 10 amperes of current at 220 volts an

arc gave fifteen minutes’ service without any adjustments being

made. At intervals after ten minutes of use there was a slight

sputtering and at the end of fifteen minutes the arc broke. Through-

out the whole time the light was serviceable. The device may be

had on lanterns furnished by the Bausch and Lomb Optical Co. and

by Spencer Lens Co. GeorceE R. La Rue.

SHORT METHOD FOR AFFIXING STAINED SECTIONS.

The following short method for affixing sections of stained

tissues has been used to good advantage. Place on a clean glass slide

a small drop of fixative prepared by mixing equal parts of oil-of-

cloves and collodion. Rub until a thin coat is forme.d Lay upon

the slide the paraffin ribbons of sections, and flatten out the latter by

pressing them down with the tip of the finger. Place the slide in

xylol until the paraffin is dissolved off and mount in balsam.

Zool. Lab. Kan. State Agri. Coil. James E. Acxert.

MOUNTING BOTANICAL MATERIAL IN SODIUM SILICATE MEDIUM.

S. F. Maxwell (Ill. Micr. Soc. Oct. meeting) recommends the

employment of sodium silicate for mounting delicate vegetable prep-

arations that do not readily endure dehydration. Use any solution

that is free from precipitated silica. Have the solution of a con-

sistency of a medium thick jelly. Place section in it, and place cover

as usual. It sets very quickly, in 24 hours, and is very durable.

No dehydration is necessary. The method is both useful and easy.

VoATt,

148 NOTES, REVIEWS, ETC.

STABLE SOLUTIONS OF GENTIAN VIOLET.

Dr. Holmes advises adding 3-5% glycerol (C. P.) to stain and

keeping in dark cool place. :

Dr. Ritchie recommends using phenol water 1 part in 10. This

retards but does not prevent decomposition.

R. Kilduffe makes two stock solutions :

a. Add 5 cc. 40% formol to 95 cc. distilled water.

b. Saturated alcoholic solution gentian violet.

Mix 25 parts of B with 75 parts of A.

It keeps long and well at ordinary temperatures. There is no

decomposition; no moulds grow on it; no modification of technic

necessary ; preparations made with it are sterile. Vario te

QUICK TEST FOR TREPONEMA PALLIDUM.

Prompt diagnosis is often necessary in cases of suspected

syphilis, and simple methods of identification of the spirocheta are

desirable.

1. Air-dry films of serum on slide obtained by scraping slight-

ly the margin of sore.

2. Pour over this and renew several times in the course of a

minute Huge’s fluid (1 cc. of acetic, 20 cc. formol, and 100 cc. of

distilled water).

3. Wash well with water.

4. Cover the preparation with the mordant (5% solution tan-

nic acid in 1% water solution of carbolic acid). Heat till steam

rises,—for %4 minute.

5. Wash 15-30 seconds with water.

6. While wet apply silver stain (%4 % of silver nitrate in dis-

tilled water, to which trace of ammonia has been added, with a

capillary pipette until a slight turbidity is evident). Heat again

until it steams.

7. Wash with water; dry with blotting paper; mount in Can-

ada Balsam. Cedar oil causes to fade.

AMERICAN MICROSCOPICAL SOCIETY 149

The jet black Treponema stands out on a clear background and

appears much larger than when stained with anilines. A one-sixth

objective is enough to identify them. Wieckto 1

Se ee

tS tae

a gee t

INDEX TO ADVERTISEMENTS

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TABLE OF CONTENTS

FOR VOLUME XXXIII, Number 3, July, 1914

A new Henlea (Enchytreide) from Northern Michigan, with Plate

UX by: Baul Si Welebicy i. se hues gis tck bs as Wee aon ete aby eben eee 155

Synopsis of Free-Swimming Fresh-Water Entomostraca of North

America, with text-figures, by Ada L. Weckel...............00.00e- 165

Notes and Reviews: Entomological Notes; Insects and Flowers;

Origin of Keimbahn-Determinants; Ceratitis capitata and Kero-

sene; Light Reactions of Dermestide; Beetles becoming Parasites ;

Practical -Photo-Micrography / 2.0.0.5 nsetasnccevdveusnaeeevenmmeees 205

NOTE

Members will notice (page I of advertising section, and TRANS-

actions for July, 1913), that grants are now being made from the

income of the Spencer-Tolles Research Fund, for the encouragement

of research with the microscope.

TRANSACTIONS

American Microscopical Society

(Published in Quarterly Installments)

Vol. XXXIII JULY, 1914 No. 3

A NEW HENLEA (ENCHYTR-EIDA) FROM NORTHERN

MICHIGAN.*

By Paut S. WEtcH.

At present more than fifty species are assigned to the genus

Henlea. Whether or not all are valid remains to be proven, but

nevertheless it is apparent that the group 1s much larger than was

formerly supposed and that it has a wide distribution, A number

of contributions to the genus have recently appeared. Friend (’12,

"13a, ’13b, ’13c, ’14) in England has added a considerable number

of new species from that country. Cejka (12, pp. 11-17) described

fH. parva and H. diverticulata from New Siberia and Kotelnoij

Islands off the coast of northern Siberia. Michaelsen (13, pp. 211-

213) added H. columbiana from Medellin, Colombia, S. A., and the

writer (’14, pp. 126-140) described H. moderata and H. urbanensis

from Illinois. Only two species of Henlea have been reported east

of the Rocky Mountains in North America and the species to be

described in this paper represents the first record of a Henlea from

Michigan. During the summers of IQII-1913 the writer made

some collections in the immediate vicinity of Douglas Lake, Michi-

gan, and a new species of Fridericia has already been described

(Welch, ’14, pp. 154-158) ) from this material. The major part of

these collections has not been worked up but the writer hopes to

present further data in the near future. The specimens on which

this paper is based form a part of the above mentioned collections.

The new species to be described below has, in some respects, a

close resemblance to the genus Hepatogaster described by Cejka

*Contribution from the University of Michigan Biological Station No. 23.

150 PAUL S. WELCH

(10) but fails to conform to the definition of that genus in lacking

the canals in the epithelium of the alimentary tract, in having the

peptonephridia confined to VI, and in having the ental opening of

the spermathece in V instead of VI. Since these discrepancies oc-

cur and since there is agreement with Michaelsen’s definition of —

Henlea this species has been placed in the latter genus.

Definition—Length, 15-19 mm. Diameter, about 0.64 mm.

Somites, 65-66. Color, whitish yellow. Prostomium blunt and

rounded. Head pore near 0/1. Dorsal pores absent. Seta of about

equal length, slightly bent proximally, 2-7 per bundle in the anterior

and middle parts of the body, usually 6, number decreases in the

posterior somites. Clitellum on XII-XIII. Lymphocytes nearly

circular. Brain slightly more than twice as long as wide; anterior |

margin concave; posterior margin distinctly emarginate; lateral

margins convergent cephalad. Peptonephridia present in VI; dorsal

and ventral parts in close contact with digestive tract; dorsal pep-

tonephridium with sparse branches which extend into ccelom. Eso-

phagus passes abruptly into intestine in VIII. Intestinal diver-

ticulum in VIII, entirely surrounding digestive tract. Dorsal vessel

arises in IX. Each nephridium with small anteseptal part; post-

septal part at least twice as large; efferent duct arises from ventral

side of latter near septum. Spermiducal funnel with length about

one and one-half times diameter. Spermathece, each with oval,

slightly expanded ampulla near ectal end; diameter diminishing

gradually toward ectal end; three or four pyriform, multicellular

glands at ectal opening; spermathece uniting dorsad of digestive

tract to form a cylindrical tube through which communication with

digestive tract is affected.

The characters of the penial bulb are discussed on a later page.

Described from two sexually mature specimens. Type and —

paratype in the collection of the writer.

The specimens on which the above description is based were

collected August 18, 1911, on the west shore of Burt Lake, Michi-

gan. They were found in deciduous woods, under the decaying

bark and in the associated dirt and debris of fallen timber. Both of

the specimens are at the height of sexual maturity and agree

perfectly in all structural details.

A NEW HENLEA FROM NORTHERN MICHIGAN Lay ev

Affinities —This species is closely related to Henlea moderata

Welch. However, distinct differences in the brain, peptonephridia,

clitellum, somites, sete, and penial bulb occur. None of the other

American species of the genus appear to be at all closely related.

A comparison with foreign species is difficult and unsatisfactory

since many of them are imperfectly described. As. the descriptions

stand at present this species appears to be distinct from foreign

forms.

External Characters.

The body has an average length of about 17 mm., the extremes

being 15 and 19. In transverse section it is circular in outline.

The maximum diameter—approximately 0.6 mm,.—is in the region

of the clitellum and the diminution caudad is very slight. Anterior

to the clitellum the diameter is about uniform. In the living speci-

mens the body is whitish and opaque. The prostomium (PI. IX,

Fig. 5) is decidedly blunt and rounded. The intersegmental grooves

are obscure, the first two or three being the only ones which are at

all distinct. The number of somites varies from 65 to 66. The

head pore is well-defined and located near the tip of the prosto-

mium. The structure of this pore will be given in detail in another

part of the paper. The clitellum is on XII-XIII and is prominent.

The number of setz per bundle varies from 2 to 7, the predominat-

ing numbers in the middle of the body being 5-7 and the smaller

numbers occurring on the first two or three somites and in the

posterior fourth of the worm. There seems to be no constant

difference in the numbers of setz in the bundles of the lateral and

ventral rows. The sete of a bundle are all of similar size and

development and, in the specimens examined, extend but a short

distance beyond the surface of the body. They are straight except

for a slight bend at the proximal end and arranged in a fan-shaped

cluster,

Internal Characters.

Body wall.—The cuticula is thin, delicate, and inconspicuous in

sections except under high magnification. The hypodermis varies

in thickness in different parts of the body. In the region of the

prostomium it attains a maximum thickness of about 0.03 mm,

158 PAUL S. WELCH

Anterior to the clitellum it has an average thickness of about 0.012

mm, and is slightly thicker on the lateral aspects than on the dorsal

or ventral ones. Immediately posterior to the clitellum the hypo-

dermis becomes very thin, never exceeding 0.01 mm. in thickness,

and usually not more than 0.006 mm. The circular and longitudinal

muscle layers of the body wall are both well-developed throughout

the length of the body, the longitudinal layer being the thicker.

The clitellum is composed of closely set, columnar cells, all

similar in shape, dimensions, and contents. The length of these

cells, which represents the thickness of the clitellum, averages about

0.078 mm. and the transverse dimension about 0.012 mm. Spherical

nuclei lie in the bases of the cells and the cytoplasmic contents take

artificial stains with uniform intensity.

The head pore (Pl. IX, Fig. 5) is located near the tip of the

prostomium and is larger than in other species of Henlea known

to the writer. Sections show the lumen to be trumpet-shaped,

widest at the ectal extremity, somewhat sigmoid in shape, and ovoid

in transverse section. At the ectal extremity the transverse dimen-

sions are as follows: sagittal dimension, 0.03 mm.; frontal dimen-

sion, 0.06 mm. Figures 8 and 9 show the structure of the body

wall in the immediate vicinity of this pore.

Lymphocytes——The lymphocytes (Pl. IX, Fig. 2) are both

large and numerous. They are very sparsely distributed in the

anterior end of the body but in V they begin to appear in large

numbers and, in the specimens which were studied in this connec;

tion, the maximum is attained in the immediate vicinity of IX

where lymphocytes are so numerous that they completely fill all of

the available space in the body cavity and are so closely crowded

together that many of them are distorted. They occur in all of the

somites posterior to the clitellum but in much reduced numbers.

The majority of the lymphocytes are almost circular in outline.

A certain proportion approach the elliptical and crowding produces

a number of other shapes. Measurements of a large number of

lymphocytes showed the diameter to vary from 0.036 to 0.054 mm,

Each has a conspicuous, central nucleus, the average diameter of

which is about 0.006 mm. The cytoplasmic contents are somewhat

reticular in appearance and have a decided affinity for artificial

stains.

A NEW HENLEA FROM NORTHERN MICHIGAN 159

Brain.—The brain (Pl. IX, Fig. 7) lies entirely in I. The an-

terior margin is concave and the posterior margin is distinctly emar-

ginate. The lateral margins converge cephalad and approach each

other closest at a point just posterior to the origin of the commissural

nerve trunks. The maximum width occurs near the caudal fourth

of the organ and is about one and one-half times as wide as the

minimum width. The ratio of the greatest length to the greatest

width is 12:5, the actual measurements being about 0.24 mm. for the

former and 0.10 mm. for the latter. In transverse section the

organ is elliptical in outline, the ratio of the greatest width to the

greatest thickness being about 10:7. The brain is attached to the

body wall by a pair of supporting strands which arises from the

lateral margins near the caudal extremities.

Peptonephridia.—Two peptonephridia are present, one on the

dorsal and the other on the ventral side of the digestive tract in VI.

Both adhere very closely to the walls of the latter and extend along

it for approximately the length of VI. Each is an irregular, tubular

mass showing ramifying lumina and nucleated walls. The dorsal

peptonephridium gives off a few irregular branches which extend

into the ccelom. No branches extend from the ventral peptone-

phridium.

Intestinal Diverticulum—The intestinal diverticulum arises

from the posterior end of the cesophagus in VIII. It is reflected

cephalad, investing closely the digestive tract for the greater part

of the length of the somite and occupying the major part of the

body cavity. It is a single structure with two shallow, unequal,

longitudinal depressions, one dorsal and the other ventral. It iS

about 0.40 mm. in length, about 0.35 mm. in sagittal diameter, and

about 0.42 mm. in frontal diameter. Sections (Pl. IX, Fig. 10)

show the organ to be made up of a series of branching, rather thick-

walled tubules which arise from the digestive tract (Pl. IX, Fig. 11)

in the posterior part of VIII, extending cephalad. At the origin

of the diverticulum the number of tubules is rather small but a

transverse section of the organ cephalad of its middle shows a large

_ number of hollow tubules, indicating that these tubules branch.

Sagittal sections also confirmed this observation. These tubules

appear to end blindly in the cephalic end of the organ since careful

160 PAUL S. WELCH

study of sections under high magnification failed to show any evi-

dence of anastomosis. Their walls contain numerous, distinct

nuclei and are glandular in appearance. The tubules are all of the

same structure although the cephalic extremities take artificial stains

more intensely than do the parts nearer their origin. The region

of the digestive tract from which these tubules arise is ciliated and

cilia are also present in the bases of the main tubules. From the

origin of the diverticulum from the digestive tract the perivisceral

blood sinus is continued cephalad, constituting the spaces surround-

ing the tubules. The latter are so closely crowded together that the

sinus spaces are reduced to a minimum. The peritoneal covering of

the alimentary canal continues over the diverticulum as a complete

investing membrane.

Structurally the intestinal diverticulum in this species ire-

sembles very closely that of Henlea moderata Welch, the difference

being minute and rather unimportant. In an earlier paper, the

writer (’14, pp. 138-139) compared the structure of the intestinal

diverticulum of H. moderata with corresponding organs of other

species of Henlea and it appeared that it possesses an unreported

type of structure. The discovery of H. tubulifera adds a second

species having a diverticulum of this type. However, it should be

noted that a very similar type of structure is found in the intestinal

diverticula of the genus Hepatogaster. The minute structure of

this organ has not been described for many of the species of Henlea

and as a consequence our knowledge of its various structural forms

is very imperfect. Recent literature contains some further data on

the character of this organ. Cejka (’12, p. 15) describes the struc-

ture of the intestinal diverticula in H. diverticulata as follows:

“Durch das IX.. und VIII. Segment verlaufen 4 grosse Darm-

taschen, die am Ende des IX. Segment durch eine weite Offnung

mit dem Darmkanale im Zusammenhang stehen( . . . ). Ihre

Wande sind verschiedenartig gefaltet und vom Blutsinus reichlich

umspilt. Im Innern der Taschen treffen wir reichliche Cilien, wie

im Darmkanale, was schon auf den gleichen Ursprung hindeutet.

Allen Umstanden nach miissen wir alle Darmtaschen der Henleinen

als Darmaussttlpungen ansehen; dagegen ist der Ursprung der

Speicheldriisen bisher unsicher.” The same writer (’14, p. 17)

a A NEW HENLEA FROM NORTHERN MICHIGAN 161

describes the intestinal diverticula in H. parva as follows: “Im

VIIL/VII. Segment befinden sich 4 grosse Darmtaschen, die nach

dem Darmepithel-Typus gebaut sind, aber nur sparlich Wimpern

tragen( .. . ). Ihre Wande zeigen fast gar keine Fpithelfalten,

was ich noch bei keiner Henlea-Art beobachtet habe, und was auf

den ersten Blich auffallend ist. Durch das Dissepiment VIII./VII.

' sind diese Darmtaschen etwas eingeschniirt. Im VIII. Segment

munden sie mit einer grossen Offnung, deren Weite dem Lumen der

Darmtaschen fast gleich kommt, in den Darmkanal.” Michaelsen

(°13, pp. 21I+213), in discussing the anatomy of Henlea colombiana,

describes certain problematical tubules in VII-IX, one on each side

of the digestive tract, which were not definitely identified but which

might possibly represent a form of intestinal diverticula.

Dorsal Blood-Vessel_—The dorsal blood-vessel arises from the

perivisceral blood sinus in IX. For the greater part of its length it

is small and inconspicuous. Swellings, about 0.04 mm. in diameter,

occur in the immediate vicinity of the third pair of septal glands

and also in IX, just before the vessel merges into the perivisceral

sinus.

Nephridia.—The first nephridia are related to V/V. There is

some variation in size and shape in the different regions of the body

but, in general, the anteseptal part is at most not more than half

the size of the postseptal part (Pl. IX, F ig. 1) and the efferent duct

arises from the ventral part of the latter, near the septum,

Spermiducal Funnel.—The spermiducal funnel (Pl. IX, Fig. 6)

is situated in the usual position in the posterior part of XI with its

base in close proximity to the lower part of XI/XII. It is approxi-

mately one and one-half times as long as wide, the maximum dimen-

sions being as follows: length 0.16 mm., diameter 0.10 mm. The

collar is distinct but small, the diameter being only about 0.04 mm.

The sperm duct is long, much contorted, and confined to XII.

Pemal Bulb.—The penial bulb (Pl. IX, F ig. 3) is simple in its

structure and conforms to the lumbricillid type. It is rather small

-as compared with the diameter of the body, somewhat elliptical in

transverse section, and is covered with a moderate musculature.

The interior of the bulb is filled with cells of but one kind. These

cells vary somewhat in shape in the different parts of the bulb, but

162 PAUL S. WELCH

in general they are greatly elongated and are arranged radially

about the penial lumen. The peripheral, nucleated parts of the cells

stain more deeply than do the extensions which approach the penial

lumen. At the ventral side of the bulb the cells merge gradually

into the hypodermis of the body wall. The sperm duct meets the

dorsal part of the bulb on the ectal side, penetrates it, and meets—

the penial lumen deep within the interior. There is sufficient dif-

ferentation of parts at the junction of the sperm duct and the penial

lumen to make the position of this union distinct.

When the penial bulb of Henlea tubulifera is compared with

that of Henlea moderata, its nearest relative, it is found that the

important difference is the absence of inner bulb cells in the former

and the presence of such cells in the latter. In other structural

respects the two bulbs are similar.

Ovaries.—The ovaries occur as usual in XII, in connection with

the ventral part of XI/XII. They are massive and fill a consider

able part of the ccelom. In the specimens examined in this connec-

tion the ccelomic cavity in XII is filled with developing ova.

Spermaries.—The spermaries are large and well-developed. In

the specimens examined they are at the height of maturity and the

available space in XI is filled with sperm cells in all stages of

development.

Spermathece.—A single pair of spermathece lie in V. The

ectal opening of each is lateral and slightly caudad of IV/V. Three

or four well-defined, multicellular glands (Pl. IX, Fig. 4) occur in

connection with the ectal terminus but no increased thickness of the

hypodermis in the vicinity of the opening is apparent. There is no

marked differentiation of duct and ampulla. Within the somewhat

swollen ectal region the lumen attains its greatest diameter of

0.021 mm. This region is thick-walled, approximately 0.06 mm. in

diameter, and includes about one-half of the entire spermatheca.

The diameter decreases entad to 0.024 mm., the swollen region

merging gradually into the duct-like portion which extends obliquely

across the ccelom to a point dorsal of the digestive tract where it

bends caudad. It meets and unites with the spermatheca of the

opposite side in the posterior part of V, to form the large common

duct which communicates with the digestive tract. This common

A NEW HENLEA FROM NORTHERN MICHIGAN 163

duct has a maximum diameter of 0.06 mm. and a total length of

0.14 mm. It extends obliquely into the wall of the digestive tract

and is

actually included within it for some distance. The total

length of a single spermatheca, exclusive of common duct, is about

0.30 mm.

Kansas State Agricultural College, May Q, I9I4.

LITERATURE CITED.

CEJKA, B.

FRIEND,

"Io. Die Oligochzten der Russischen in den Jahren 1900-1903 unter-

Enchytreiden (Hepatogaster). Mém. Acad. Sci. St. Pétersb.

nommenen Nordpolarexpedition. I. Uber eine neue Gattung der

(8), 29, No. 2:1-29. 3 pl.

12. Die Oligochaeten der Russischen in den Jahren 1900-1903 unter-

nommenen Nordpolarexpedition. II. Ueber neue Bryodrilus-

und Henlea-Arten. Mém. Acad. Sci. St.-Pétersb. (8), 29, No.

6:1-19. 4 pl.

12, British Enchytreids. IV. The Genus Henlea. Jour. R. Micr.

Soc., pp. 577-598. 11 figs.

13a. British Enchytreids. V. Species new to Science. Jour. R.

Micr. Soc., pp. 255-271. 13 figs.

’13b. Annelid Hunting in Notts. Second Paper. 60th Report and

Transactions of the Nottingham Naturalists’ Soc. for IQII-1912,

Pp. 50-64.

‘13c. Some Jersey Oligochets. Zoologist (4) 17:456-464.

14. Annelid Hunting in Notts. Third Paper. 61st Report and

Transactions of the Nottingham Naturalists’ Soc. for 1912-1913,

Pp. 20-38.

MICHAELSEN, W.

WELCH,

13. Die Oligochaeten Columbias. Voyage D’Exploration scien-

tifique en Colombie. Volume V des Mémoires de la Sociéte

neuchateloise des Sciences naturelles, pp. 202-252. 1 pl.

Pp. Ss.

14. Studies on the Enchytreide of North America. Bull. Illi-

nois State Lab. Nat. Hist., 10:123-212. 5 pl.

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

olckey A

Fig. 8.

Fig. 9.

Fig. 10

Fig. I1.

EXPLANATION OF PLATES.

Dae

d. bl. v.,

lum. dig. tr.,

or. tu. div.,

pen. b. i,

pen. lum.,

pen. po.,

per. gl. c’l,

ri,

sp. d.,

tu. div.,

ABBREVIATIONS.

blood sinus.

dorsal blood vessel.

lumen of digestive tract.

origin of tubules of diverticulum.

penial bulb invagination.

penial lumen.

penial pore.

peripheral gland cells.

retractor muscle.

sperm duct.

tubules of diverticulum.

FIGURES.

Henlea tubulifera, n. sp.

Outline of typical nephridium.

Lymphocyte.

Penial bulb in transverse section of the worm.

Spermatheca.

Outline of anterior end of worm, lateral view.

Spermiducal funnel.

Outline of brain, dorsal view.

Head pore as it appears in sagittal section of the worm.

Head pore as it appears in transverse section of the worm.

Drawing is made from section caudad of ectal opening.

Transverse section of digestive tract in VIII, showing structure of

intestinal diverticulum.

Transverse section of digestive tract in posterior part of VIII,

through origin of tubules of intestinal diverticulum.

per.gl.c')

a,"

HTenlea tubulifera n. sp.

(PI IX, Figs. 1-11)

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ne ‘ 7 - ars

J ae SP) 7 q

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