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HARVARD UNIVERSITY.

LIBRARY

MUSEUM OF COMPARATIVE ZOOLOGY.

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^^-vnl^T. I J%'^) jhd.^ijjJ2 I L

0, /^JD

THE

TEANSACTIONS

OF

THE LINNEAN SOCIETY

OF

LONDON.

SECOND SERIES.— VOLUME VII.

ZOOLOGY.

LONDON:

PRINTED BY TATLOK AND FRANCIS. BED LION COUET, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BTJRLINGTON HOUSE;

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

1896-1900.

.■A

AUG 10 1900

C O N T E N T S.

PART I.— December, 1896.

I. Heport on a Collection of Cephalopoda from the Calcutta 31tiseum. By Edwin S.

Goodrich, B.A., F.L.S., Assistant to the Linacre Professor of Comparative

Anatomy, Oxford. (Plates 1-5.) pages 1-24

PART II.— May, 1897.

II. Amphipoda from the Copenhagen Museum and other Sources. — Part I. By the

Bev. Thomas R. R. Steering, 31. A., F.B.S., F.L.S. (Plates 6^14.) . . 25-45

PART III.— June, 1897.

III. The Origin of the Corpus Callosum : a Comparative Study of the Hippocampal

Begion of the Cerebrum of Marsupialia and certain Cheiroptera. By G. Elliot

Smith, Jf.Z)., Ch.M. {Sydney), "James King" Besearch Scholar of the University

of Sydney ; St. John's College, Cambridge. (Comtnunicated by Prof. G. B. Howes,

Sec. Linn. Soc.) (Plates '15 &'16.) 47-69

PART IV.— Jlne, 1898.

IV. On the Muscular Attachment of the Animal to its Shell in .some Fossil Cephalopoda

{Ammonoidea) . By George Charles Crick, F.G.S., F.Z.S., of the British

Museum {Natural History). {Communicated by the President, Dr. A. GOnther,

M.A., F.B.S.) (Plates'^lT-SO.) 71-113

PART v.— October, 1898.

V. Observations on the Structure and Morphology of the Cranial Nei'ves and Lateral

Sense Organs of Fishes ; toith special reference to the Genus Gadus. By Erank

J. Cole, Demonstrator of Zoology , University College, Liverpool. [Communicated

by Prof W. A. Herdman, D.Sc, F.B.S.) (Plates 21-23.) .... ' 115-221

[ iv ]

PAUT VI.— November, 1898.

VI. A Contribution towards our Knowledge of the Morphology of the Oiols. By

^N.V.VYCY^\Y■v, A.L.S.,M.B.O.U. (Plates '24-29.) pages 223-275

PAET VII.— January, 1899.

VII. The Brain in the Edentata. By G. Elliot Smith, M.B. (Sydney), St. John's

College, Cambridge. {Communicated by Prof G. B. Howes, F.E.S., Sec. Linn.

Soc.) (With 36 Illustrations in the Text.) 277-394

PART VIII.— May, 1899.

VIII. Amphipoda from the Copenhagen Museum and other Sources. — Part II. By

the Bev. Thomas R. E. Steering, 3LA., F.B.S., F.L.S. (Plates ""SO^.) 395-432

PART IX.— November, 1899.

IX. On Fossil and Recent Lagomorpha. By C. I. Porsyth Major, M.B. {Com-

municated by Prof G. B. Howes, Sec. Linn. Soc.) (Plates ''36-39.) . 133-520

PART X.— March, 1900.

X. On the Genus Lemnalia, Gray; with an Account of the Branching -systems

of the Order Alcyonacca. By Gilbert C. Bourne, M.A , F.L.S. , Fellow

and Tutor of New College, Oxford; TJnicersity Lecturer in Comparative

Anatomy. (Plates'40-42.) 521-538

PART XL— March, 1900.

Titlepage, Contents, and Index 539-550

ERRATA.

Page 180, line 'I'l from toj), tor Fierasfer dentulus read Ficrasfir dcntutas.

Page 228, line 9 from bottom, for Pterohjsis read Pterylosis.

Page 242, line 10 from bottom, for cops letjcotis, Temm., read Scops LEncoiis, Temm.

Page 285, line 3 from bottom, for Ohlamdyoj^Jiorus read Chlamydophorus.

Page 516, line 17 from toji, for J'lvhiyiis iniiiKjctisis, Kon., read Prolagus ceniiigensis, Kon.

'/ (/ "T^

2nd Ser. ZOOLOGY.]

[VOL. VII. PART 1.

THE

^^/l.

^ - 12^

TRANSACTIONS

OF

THE LINNEAN SOCIETY OF LONDON.

REPORT ON A COLLECTION OF CEPHALOPODA

FROM THE CALCUTTA MUSEUM.

BY

EDWIN S. GOODRICH, B.A., F.L.S.,

ASSISTANT TO THE LINACHK PROFESSOR OF COMPAKATIVK ANATOMY, OXFORD.

LONDON:

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RKD LION COURT, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

December 1896.

TRANSACTIONS

OF

THE L I N N E A N SOCIETY.

I. Report on a Collection of Cephalopoda from the Calcutta Iluseum. By Edwin

S. Goodrich, B.A., F.L.S., Assistant to the Linacre Professor of Comp. Anatomy,

Oxford.

(Plates 1-5.)

Eead 19th December, 1895.

TiAST year Professor E. Ray Lankester received for examination from the Calcutta

Museum a large collection of Cephalopods, which he kindly handed over to me to be

identified. The work was carried on at the Oxford Museum and at the British Museum,

Cromwell E-oad, and I must express my thanks to Dr. A. Glinther and Mr. E. A. Smith

for placing the collections in the latter Institution at my disposal.

The present collection is composed almost entirely of specimens captured during

the voyages of H.M.S. 'Investigator.' It contains 162 specimens, belonging to 28

genera.

Eleven new species are described, belonging to the genera Inioteuthis, Sepia, Loliolus,

Sepioteuthis, Abralia, Cheiroteuthis, Histiopsis, Taonius, and Octopus. No new genus

has been foimded ; but four genera included are new to the Indian region. Of these the

genus Calliteuthis has been recorded from the Atlantic and Pacific regions ; the ^genus

Histiopsis from the Atlantic ; and the genera Loliolus and Inioteuthis from the Pacific

and Japanese regions.

SECOND SERIES. — ZOOLOGY, VOL. VII. 1

2 MR. E. S. GOODEICH ON A COLLECTION OF

DECAPODA MYOPSIDA.

Family SEPIOLINI.

Iniotetjthis maculosa, n. sp. (PI. 1. figs. 1, 2, & 3.)

One specimen from the Anclamans, and another from the Persian GuK ; both females.

The principal measurements of the first are * : —

Length of mautle (lower surface) TS centim.

Breadth „ '95

„ „ . attachmeut to neck '4 „

,, between fins '8 ,,

J, across eyes '7 „

„ of fin '4 „

Length of fin-attachment '4 „

„ from extremity of mantle to tip of dorsal arm . 2'4 ,,

Length of dorsal arm '8 „

„ dorso-lateral arm "10 „

„ ventro-lateral „ '11 >,

„ ventral „ '7 »

„ tentacular „ 2'1 „

„ „ club '5 „

The mantle is rounded at its apex. The round fins are attached about halfway up the

mantle. The band uniting the mantle to the neck is narrower than in In. Morsei. The

funnel has a small opening, and a wide base on which are l-shaped sockets. The two

muscular bands which unite the base of the funnel above the sockets to the head are

less prominent than in Sejnola oi' In. Morsei. There are glandular pads and a small

valve inside the funnel.

The edge of the bviccal membrane is notched, but the lobes are not distinctly

marked.

The first two pairs of arms are rounded ; the ventro-lateral arms are slightly keeled ;

the ventral arms are provided with a well-developed keel on the upper edge. They all

bear two rows of round suckers, obliquely set on slender stalks rising from a swollen base.

The opening of the sucker is wide ; the horny ring has an ornamented surface and a

smooth edge.

The tentacular arms are flattened, and a groove runs down tbe inner surface. The

club is of great Iciigth, slightly enlarged, provided with a lateral membrane on both

sides, and a large niimber of minute suckers in eight rows. Each sucker is nearly hemi-

spherical, set obliquely on a long slender stalk (fig. 3). The papillary area of the horny

ring is wide, and the edge armed with alioiit 15 teeth (fig. 2).

The ground-colour of the first individual is pale brownish yellow, inclining to orange

* In the following descriptions the terms " upper " and " lower " are used to denote the surfaces generally called

" dorsal " and " ventral ; " since, strictly speaking, they do not correspond to the morphological dorsal and ventral

surfaces.

CEPHALOPODA PEOM THE CALCUTTA MUSEUM. 3

on the arms and upper surface of the mantle. Scattered over the mantle, more especially

on the lower surface, are large hrown chromatophores (fig. 1) ; similar clu'omatophores

are seen on the upper surface of the fins, and on the head and arms. There is a con-

spicuous row of five between the eyes on the upper surface of the head.

The second specimen is of a duller tint and less well preserved.

This species appears to he more closely related to Iniotenthls japoiiica (Tilesius, MS.),

Verrill, which also has two rows of suckers on the arms, than to In. Morsel, Verrill,

which has foiu*.

Inioteuthis Moksei, Verrill.

Seven specimens from the Andamans have been placed in this species.

FamUy SEPIAEII, Stp.

Subfamily Sepiadarii, Stp.

Sepiadarium Kochii, Stp.

FoLU' specimens, all female. One from off the south coast of Ceylon, lat. 6° 6' 30" N.,

long. 81° 23' E., from a depth of 32 fathoms. The other three from the Andamans.

Sepia singaporensis, Pfeff'er.

One female specimen from Singapore.

Sepia aculeata, von Hasselt.

Ten specimens apj)ear to belong to this species. One from the Irawaddy delta, at a

depth of 20 fathoms ; four from Port Blair, and five from the Andaman Sea.

Sepia singalensis, n. sp. (PI. 1. figs. 4, 5, 6, 7, & 8.)

Two male specimens ; the first from Colombo, the second from off Point Galle (?).

The principal measurements of the former are : —

Length of mantle (above) 16 ceutim.

(below) 14-1

„ from „ apex to mouth . . . 17'4. „

Breadth of „ at origin of fins . . . 4'9 „

„ » halfway 6-2 „

fin 1-2

)>

Length of dorsal arm 7 „

„ dorso-lateral arm 6"5 „

„ ventro-lateral „ 6"3 „

„ ventral „ Q-7 „

„ tentacular „ 12'7 „

„ „ club 3-1

„ pen 15'5 „

Breadth of „ 4-8 „

1*

4, ME. E. S. GOODEICH ON A COLLECTION OF

The mantle is of a narrow oval shape ; the strong fins arise a little way below the

mantle-margin, and do not join at the ajiex (fig. 4). The siphon is thick-walled, with a

somewhat crescentic opening; it does not reach to the junction of the ventral arms.

The arms have broad compressed bases (especially the ventral arms, which are 23 mm.

broad), without well-developed keels. The inner surfaces, bounded on either side by

narrow lateral membranes, bear four rows of moderate-sized suckers, largest on the

lateral arms, where they attain a diameter of 2 mm. On the distal half of the arms the

suckers become extremely small. The horny ring of the arm-suckers has a narrow

paj)illary area, and a margin smooth on the proximal two-thirds of its circumference,

and armed with very irregular teeth on the distal third (fig. 8).

The stem of the tentacle is compressed, forming a sharp edge on the outer surface.

The club is furnished as usual with a wide keel springing from the upper surface.

Svickers of very unequal size are jjlaced in four rows on the proximal region ; the largest

attain a width of 4 mm. in the two central rows, and are provided with smooth horny

rings. The suckers diminish rapidly in size at either end ; these and the suckers of the

outer rows have horny rings armed all round with numerous sharp teeth (fig. 7). In the

distal region the small suckers are closely packed in six or seven rows, and near the

extreme apex two suckers stand out from the rest on the upper margin as if utilized for

some special purpose (an arrangement I have noticed in Sepia officinalis).

The buccal membrane has seven lobes provided with a few suckers, the horny rings of

which closely resemble those of the arm-suckers.

A small Aveb is developed at the bases of the arms except of the ventral jiair.

The mandibles are shown in fig. 6.

The long oval pen of this Sepia is very remarkable (fig. 4). Above, the rough

calcareous surface raised in three slight ridges narrows anteriorly, and is bounded on

either side by a broad expanse of the chitinous margin {ch.m.) (in places about 1 cm.

broad). Below, the striated area formed by the loculi reaches far up (loc), and is marked

in the centre by a longitudinal groove. The margin of the inner cone is produced

forwards and reflected over the posterior loculi, to which it is closely applied (i.e.).

The apical spine has unfortunately been broken off ; it appears to have been small.

It is not without hesitation that I have placed these specimens in a new species, as

they closely resemble Sepia Bouxii, d'Orb., described in d'Orbigny and F^russac's

monograph from the Indian seas (5).

There are, however, several characters in which the two species differ. "Whereas

5. Mouxii is of a " forme generale racourcie," has very wide fins, and toothed rings to all

the suckers of the tentacular club, S. singalensis is of narrow shape, with moderate fins,

and smooth rings on the largest suckers. On the other hand, their pens are remarkably

similar.

The ground-colour of the best specimen is pale brown, speckled vnih. slate-coloured

chromatophores on the lower surface, and conspicuously striped with broad dark bands

on the ixpper surface of the mantle, head, and arms.

The hectocotylized region is short and sitviated about halfway up the left ventral arm.

CEPHALOPODA FBOM THE CALCUTTA MUSEUM. 5

At this point the suckers are small and resting on elevated transverse ridges. Scattered

about the siphon of one specimen are spermatophores, conspicuous for the covering of

black adhesive substance at the base (fig. 5).

Sepiella inermis (van Hasselt, MS.).

Among the 25 specimens referred to this species there is great variation as to general

appearance, shape, width of the fins, and details of the structure of the pen. Neverthe-

less I have not been able to distinguish any modifications of specific importance. The

differences in the soft parts seem to be due to varied preservation. Six specimens were

captured near Madras, three near Bombay, five at Sandlieads, one in the Chilka Bight,

one at Mergui, two at Singapore, two at Penang, and five off the Ganjam coast at a depth

of 10 fathoms.

PamHy LOLIGINEI.

Sepioteuthis indica, n. sp. fPl. 1. figs. 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, & 19.)

Although the nine specimens in the collection belonging to the genus Sepioteuthis

differ considerably in size and colour, I refer them all to one species. The best-

preserved individuals are of a pale brownish-yellow ground-colour, sprinkled with slate-

coloured chromatophores, very thickly on the upper surface of the mantle, head, and

arms, more sparsely on the lower surface.

Seven specimens come from the Andamans, and two from Singapore.

Below are the principal measurements of a large male and of a large female : —

Large Male. Large Female,

centim. centim.

Length of mantle (lower surface) .... 15'5 18"3

Breadth „ near margin 5"1 5'9

„ „ halfway 5-1 6*1

„ fin 7 cm. from mantle-edge . . . 2'9 2'9

ir, £ ii 1 .1 12-5 cm. from") n c-

„ „ 10 cm. trom mantle-edge ... 3 \ o'b

mantle-edge J

Length of dorsal arm 5"2 5"5

„ dorso-lateral arm 6"3 6*5

„ ventro-lateral „ 8 9

„ ventral „ 7-4 8"6

„ tentacular „ 13'5 15

club 5-2 Q-7

Length of pen . . . ^ \2> cm. $ 20"5 cm. 12-7 cm.

Breadth of pen . . . 2"4 4 3

Prom the outline figure given (fig. 9) it Tvdll seen that the fins are perfectly rounded,

while the mantle from about halfway tapers to a blunt point ; the whole forming an

almost perfect oval. In this respect this species resembles 8. BlaiiwilUana, Per., and

S. mauritiana, Q. & G. The fins begin "35 cm. from the margin of the mantle and join

6 MK. E, S. GOODRICH ON A COLLECTION OF

behind at the aj)ex. The siplion presents no peculiarity. The olfactory fold below the

eye is prominent, undulating, and with its two extremities turned forwards (fig. 13).

The buccal membrane is large (in one specimen extending 2 cm, beyond the mandibles),

and provided with seven lobes bearing suckers. The horny ring of the latter is armed

on its distal border with strong teeth (fig. 15). The jaws are shown in fig. 14. Adhering

to the buccal membrane of tliis specimen (a large female) are spermatophores very

similar to those oi LolUjo Indica (PI. 2. fig. 28), but slightly thicker.

The powerful arms are provided on both edges of the inner surface with a lateral

membrane, strengthened by transverse muscular ridges springing fi'om the base of the

suckers. This membrane is especially well-developed on the lower edge oE the second or

dorso-lateral arm. A median outer keel is developed along the dorsal and ventro-lateral

arms ; a lateral keel on the outer lower edge of the dorso-lateral arm ; and two lateral

keels on the ventral arms, the upper one being large and membranous.

The suckers, closely set in two rows, are of moderate size, largest on the dorso-lateral

arms, where they attain a diameter of -35 cm. The horny ring is armed with from 20

to 28 strong teeth (generally 21-22), rather larger on the distal border (fig. 17).

The stem of the tentacular arm is thick, and flattened near the base (13 mm. broad

aboixt 5 cm. from the base in the large female already mentioned), from the inner edge of

which springs a membrane reaching down below the buccal membrane. The club is

wide, provided with a keel on its outer edge and with a membrane on either side, and

bears four rows of suckers of tmequal size. The largest suckers, situated towards the

centre of the club, reach a diameter of 5 mm. ; their horny rings are armed usually with

15 teeth (figs. 18, 19) (sometimes with 16-18 teeth). The smaller distal and proximal

suckers and the outer rows of suckers usually have 17 large sharp teeth on the distal

border. At the tip of the club is a slightly spoon-shaped expansion, on which the

suckers are modified, and arranged in two rows on either side enclosing a space (fig. 12).

These suckers are highly specialized, being small, flat, and very short-stalked ; the

papillary area of the horny ring is very wide and beset with rows of conical teeth

reaching the margin (figs. 11 & 12). Such a special group of suckers constitute what I

shall call the apical set, an arrangement which has not, so far as I am aware, been

noticed by previous observers in the Myopsida. It is found in both sexes, and reminds

us strongly of a somewhat similar group in Onychotenthls; the apical set of suckers,

perhaps, forms a sort of " connective appai^atus." It occurs also in Loligo JPealei and

L. indica ; on the other hand, it appears to be absent in L. marmora and in the genus

Loliolus.

^ In the male the hectocotylized left ventral arm is modified from about the 23rd pair

of suckers to the tip. In this region (fig. 16) the suckers are reduced to conical papillge.

The right arm, as noticed in other species by Steenstrup (7), is also slightly modified, the

suckers near the tip being unusually small.

The pen is very like that of SejjioteutJns Blainvilliana, Fer., thin, lanceolate, convex

above, with a strong, raised, convex ridge down the middle (fig. 10).

It is often very difiicult to distinguish between the various species of this genus

described by authors. Sepioteuthis Blainvilliana, Fer., and S. nlauritiana, Q. & G. (5),

CEPHALOPODA FEOM THE CALCUTTA MUSEUM. '7

•seem to be tlie nearest allies of this new species. Prom the former it is distinguished by

the lesser number of teeth on the homy rings of the arm and tentacular suckers, by the

presence of suckers on the buccal membrane, and by the undulation of the olfactory

■.crest (?). From the latter, S. maurltiana, it is distinguished by the lesser number of

teeth on the horny ring of the slickers and by the sliape of the pen.

LOLIGO INDICA, Pfeffer. (PI. 2. figs. 20, 21, 22, 23, 24, 25, 26, 27, & 28.)

To this species arc referred eight specimens from Mergui, one from Camorta Harbour,

one from Daley Sandheads (1887), and two from the mouth of the Mutlah River; also,

with some hesitation, a large female from the Ohilka Bight.

The first 12 specimens differ little in size ; below are the measurements of a male and

of the large female mentioned above : —

6- ?•

ecntim. ceutim.

Length of mantle (npper surface) 9"1 14

Breadth „ at beginning of tins .... \Q 3

Length of fin-attachment 5 7"6

Breadth of fins combined -i'S 7"65

Length of pen of a smaller ^ , 6'6 centira., breadth ] -2 centim.

„ „ the large 2 , li centim., breadth 2-7 ceutim.

I feel obliged to go into some detail concerning this species, since the figures and

descriptions published by Mr. Hoyle of the ' Challenger ' specimens (i) differ widely from

Dr. Pfeffer's original description (6).

Concerning the horny ring of the suckers of the arms, Pfeffer says, " Armringe mit 6

ziemlich grad viereckigen Zabnen ; darauf folgt die erhabene Leistc, die vorn nocli

jederseits cine Einkerbung als Paxdiment eines Zahnes zeigt." This hardly agrees with

Hoyle's figures, but corresponds exactly to my figure of the horny ring of the female

(fig. 26).

With regard to the horny ring of the suckers of the arms, I find that there is a well-

marked sexual difference, for in the males these rings are armed with from 9 to 11

rounded teeth (fig. 20).

Again, concerning the horny ring of the tentacular suckers, Pfeffer says, " Grosse

Tentakelringe mit etwa 21 spitz dreieckigen Zahnen, deren Basis schmaler ist, als die

Zwischenraume." While this description differs much from Hoyle's figures, it agrees

entirely with what I find (fig. 27). iVlthough 21 is the usual number of teeth in these

specimens, there are sometimes as few as 15 in the large female. Pig. 24 shows the

horny ring armed with G strong teeth from one of the very small distal suckers of the

ckib ; while fig. 25 represents a portion of the horny ring from one of the suckers of the

apical set at the tip of the club (cfr. Sepiotetdhis, j). 0).

The lobes of the buccal membrane are provided with small toothed suckers, the horny

ring of which is shown in fig. 21. I figure also a club-shaped spermatophore removed

from the buccal membrane (fig. 28).

'8 ME. E. S. GOODEICH ON A COLLECTION OF

The hectocotylized arm of the male is strongly modified. On its proximal half are

two rows of small suckers (fig. 22) ; on the outside of these the upper edge of the arm

is drawn out into a wide thick flap (fig. 22, Ji.). On the distal half of the arm the

suckers are reduced to rounded projections {m.s. fig. 23) which bend over a groove.

The outer and upper edge of the arm is developed into a lateral membrane of considerable

width {l.m. fig. 23).

LoLiOLrs iNVESTiGATOKis, n. sp. (PI. 2. figs. 29, 30, 31, 32, 33, 34, 35, 36, & 37.)

Nine specimens, some of which are much mutilated. The specimen figured and one

other come from the Mutlah River, five from the Ye River, one from Mergui, and one

from Sangor. They vary considerably in size ; the following are the principal

measurements taken on the specimen figiu'ed, a male of average size : —

Lengtli of mantle (upper surface) ....

„ from apex of mantle to base of arms

Breadth of mantle near edge

„ across eyes ....

„ „ combined fins

Length of attachment of fins

„ dorsal arm

dorso-latcral arm

ventro-lateral „

ventral „

tentacular „

The mantle is of conical shape, with a roimded apex ; its margin projects on the upper

surface into a small point above the neck, and below on either side of the funnel (figs. 29

& 30). The fins have rounded anterior and lateral edges ; the two together form a

heart-like figure. They join and are continued beyond the mantle apex.

The head is large and provided with a transverse olfactory crest below the eye. The

siphon possesses a valve, and muscular bridles hidden below the skin.

The three dorsal pairs of arms bear on their outer sui'face a median keel, especially

well-developed on the 3rd pair. The ventral arms are somewhat square in section, and

both the outer edges are drawn out into lateral keels. Small lateral membranes spring

from the inner surface on the ujiperside of the 1st and 2nd pairs of arms, and on both

sides of the 3rd and 4th pairs of arms. The suckers, in two rows, are obliquely set on

their stalks (fig. 36) ; the horny ring is provided with three large blunt teeth (fig. 37).

The tentacular arms enlarge distally into small c]u.bs, bearing an outer keel and four

rows of suckers. The horny ring of these is armed with sharp teeth on its distal border

(fig. 35).

A few small suckers are situated on the seven lobes of the buccal membrane ; their

horny ring strongly resembles that of the tentacular suckers, but there are only from

four to six large teeth.

The mandibles are rather weak (fig. 34). The lower mandible has a sharp, hard,

tooth-like point and a small basal tooth (b.t. fig. 34 b).

CEPHALOPODA FROM THE CALCUTTA MUSEUM. 9

The pen is lanceolate; narrow anteriorly, it broadens out to a thin blade behind

(fig. 31).

In the male the left ventral hectocotylized arm is somewhat sickle-shaped (figs. 29

& 32). The upper outer edge is developed into a wide lateral membrane [l.m. fig. 33),

and the suckers are more modified than in Steenstrup's species (7), the upper row being

reduced to mere papillae, and the lower row having almost entirely disappeared (fig. 33).

OIGOPSIDA.

Family ONYCHII.

Abralia andamanica, n. sp. (PL 2. figs. 38, 39, 40, 41, 42, 43, 44, & 45.)

Three specimens, captured at a depth of from 188 to 320 fathoms in the Andaman

Sea, belong to this species. The following are the measurements of the largest specimen,

a female (fig. 38) : —

Length of the mantle (lower surface) 3"8 centim.

„ from mantle-edge to base of arms . . . 1"2 „

,, of attachment of fins 2'3 „

„ from mantle-ajDcx to angle of fin ... 2*7 ,,

Bi-eadtli of combined fins 3'4 „

Length of dorsal arm 1-7 „

„ dorso-lateral arm 2 „

„ ventro-lateral „ 1*8 „

„ ventral „ 2 „

„ tentacular „ 4 „

club -8 „

Length of pen of a male, 2'4 centim., breadth 35 centim.

The mantle is nearly conical, tapering gradually to the apex. At the free edge there

is no pronounced dorsal point, but there is a small projection on each side of the funnel

(figs. 38 & 39). The fins, rhomboidal in shape, reach about halfway np the mantle ;

their posterior edge is slightly concave, their anterior convex and more rounded.

The head is large, and fits closely on to the edge of the mantle. At the edge of the

eyelid is a rudimentary sinus. On each side of the neck are two olfactory crests, the

smallest being nearest the siphon. There is a well-developed valve in the funnel ; and

the socket at the base of the latter is l-shaped. The buccal membrane has 8 lobes ; its

nner surface is covered with pajiilte of considerable size.

The first and second pairs of arms have a median external keel, and a small lateral

membrane on the upper edge. The third, or ventro-lateral, pair has a large membranous

keel {k, fig. 38), and a membrane along the lower edge. The ventral arms have the

outer and upper edge drawn out into a lateral keel.

All these arms bear two row^s of hooks for about three fourths of their length, and two

rows of suckers on the distal quarter. On the ventral arm, for instance, 14 hooks and

SECOND SERIES. — ZOOLOGY, VOL. VII, 2

10 ME. E. S. GOODEICH ON A COLLECTION OF

12 suckers can be counted. These suckers are very obliquely set on short stalks

(figs. 42 & 43), and of a compressed conical shape. The horny ring is studded with

tectli, and the margin is armed with small teeth on the proximal side and large blunt

teeth on the distal side.

The tentacular arms are scarcely at all enlarged to form the clubs (figs. 38 & 40).

Each club bears a small keel externally, three hooks along the lower edge of the internal

surface {Ji), and above these two rows of suckers. Beyond the hooks on the distal region

small suckers are arranged in four rows. The horny ring of the suckers is furnished

with small teeth round its margin (figs. 44, 45). Near the base of the club a set of

three small short-stalked suckers alternating with three tubercles forms a connective

apparatus {c. app. fig. 40).

^i§. 41 (a & b) shows the pen of a small male, the mantle of which is 3 cm. long ; it

is lanceolate, with a strong median ridge. This specimen has a large bundle of sperma-

toj^hores in the mantle-cavity.

In colour the female is of j)ale yellowish-brown tinge, inclining to orange on the upper

surface, covered with dark purjile-brown chromatophores, most numerous on the upper

surface of the mantle, head, and arms, and on the buccal membrane. The male is paler,

the chromatophores being less numerous.

Both sexes are provided with a very large number of small dark tubercles, generally

showing a white opaque lens in the centre, distributed over the lower surface of the

mantle, head, funnel, and ventral arms (tig. 38).

These tubercles, no doubt luminous or phosphorescent organs, are evenly scattered

over the lower surface of the mantle ; on the siphon they are situated in six irregular

longitudinal series ; on the head there is a row round the lower half of each eye and

nine rows between these. Three rows extend on to the base of the ventral arms, but

only two are continued to their extremities.

Abralia lineata, u. sp. (PI. 3. figs. 46, 47, 48, 49, & 50.)

Two specimens ; one, a male, taken at a depth of 265 fathoms in the Andaman Sea,

the other, a female, at a depth of from 90 to 100 fathoms off the Ganjam coast.

The principal measurements of the first specimen, which is the one figured, are given

below : —

Length of the mantle (upper surface) 1"5 centim.

,, „ (lower surface) 1"3 „

„ from mantle-apex to base of arms ... 2 „

,, of attachment of fin "8 „

„ of jjosterior border of fin '9 „

Breadth of mantle "6 „

,, combined fins 1'5 ,,

Length of dorsal arm ■" ,,

„ dorso-lateral arm I'O ,

„ ventro-lateral „ "9 „

., ventral ,, I'l „

,, tentacular „ 1"6 ,,

CEPHALOPODA PBOM THE CALCUTTA MUSEUJM, 11'

The sliort mantle tapers to a sharp point. The fins are rhomhoidal, with anterior

rounded horder and nearly straight posterior border ; they extend forwards more than

halfway up the mantle beyond the point of attachment. The head, of about the same

width as the mantle, is provided with large eyes, and fits less closely on to the mantle

than in the preceding species (this may be due to differences in preservation). A small

olfactory crest is situated behind the eye. The funnel has a valve, two well-marked

bridles, and l-shaped sockets.

The buccal membrane has 8 lobes.

The three dorsal pairs of arms are rounded proximally and slightly keeled distally.

The ventral arms have a lateral membrane on the upper side. Two rows of hooks are

borne by all the arms along almost their entire length. The ventral arms appear to bear

no suckers at all distally, but their tips are swollen, and pi'ovidedin both sexes with three

large convex pigmented organs forming a sort of club. These swellings are probably

phosphorescent organs ; they correspond exactly to the modified arms described by

Pfeffer in Enoploteuthis Iloylel, Pfelfer, and considered by him to be due to hectocotyli-

zation. The other arms bear, near their extremity, a small number of minute suckers,

the horny ring of which is armed on the distal margin with large teeth (fig. 49).

The tentacular arm is slightly expanded to form a club, bearing in the middle region

four hooks on the lower side, and three hooks alternating with suckers on the upper

side (fig. 48). Beyond these are four rows of small suckers, with a wide ornamented

papillary area and a smooth margin (fig. 50). At the base of the club is situated the

connective apparatus of four suckers and tubercles (<?. app. fig. 48).

The pen of the second specimen has been lost ; the type-sj)ecimen figured I have not

dissected.

The most striking characteristic of this pretty little Ceplialopod consists in the distri-

bution of the phosphorescent organs in regular rows on the lower surface of the mantle,

funnel, head, and two ventral pairs of arms. The w'hole animal is of a creamy-white

colour, with a few browmish chromatophores at rare intervals, more especially on the

upper surface ; two of these, of exceptional size, are situated on the upper su.rface of

the head between the eyes (fig. 46). The eyes and buccal membrane are of a deep

purplish-brown colour. The phosphorescent organs already mentioned are arranged in

six longitudinal rows on the mantle, of which the two central rows are the widest ; also

on the funnel in six irregular rows (fig. 17). A row surrounds the lower half of each

eye, and three rows extend between these. The median row' bifurcates and runs up the

two ventral arms, together with the lateral rows. The ventro-lateral arms are provided

with one row of these organs, and a few are scattered along the edge of the mantle and

over the neck. The ventral arms are abnormally long and slender, and it seems probable

that the special organs already described at their tips are phosphorescent and used as

search-lights.

Onychoteuthis Banksii, Leach.

I refer provisionally one male specimen from Sandheads, and one large female

captured at a depth of 272 fathoms in the Bay of Bengal, to this species.

2*

12 MK. E. S. GOODRICH ON A COLLECTION OE

The latter only lias an apical set of suckers to the tentacular club.

This genus is greatly in want of revision by some naturalist who cotild have access to

the type-specimens.

Family TAONOTEUTHI.

Subfamily Cheiroteuthid^.

Cheiroteuthis macrosoma, n. sp. (PI. 3. figs. 51, 52, 53, 54, 55, 50, & 57.)

A single female specimen of this elegant Cephalopod was captured off the Kistna

delta, lat. 12° 50' N., long. 81° 30' E., at a depth of 475 fathoms.

From figure 51 and the measurements given below, it will be seen that this new

species of Clieiroteutlds is remarkable for the great length and graceful tapering of the

mantle.

Length of body and arms (without tentacles) . . 69 centim.

„ mantle (lower surface) 36 „

„ „ (upper surface) 38'5 „

Breadth of „ 6 „

Circumference of mantle 18 „

Length of attachment of fins 14"8 „

Breadth of combined fins 13 ,,

Length of mantle-apex beyond fins 6 ,,

Breadth of „ ,, „ 2"5 „

Length from base of arms to posterior edge of

funnel 10 ,,

Length of funnel 5 „

Aperture of funnel 1"3 „

Diameter of external eyelid 1 „

Length of dorsal arm 14'25 „

„ dorso-lateral arm 16 „

,, ventro-lateral „ 22 „

„ ventral ,, 27 „

Maximum width of lateral membrane —

On ventral arms 1"2 „

On ventro-lateral arms 1 „

On dorso-lateral arms '4 >,

Length of pen 40*4 „

Breadth „ "75 „

The colour of this specimen in spirit is of a dull purplish-brown, lighter and yellower

on the lower surface, darker and inclining to heliotroije and blue on the uppper surface

of the mantle, head, and on the outer surface of the arms. The buccal membrane, inner

surface of the arms and suckers are paler.

The mantle, as seen in the figure from the ventral surface, tapers gradually until the

middle of the fin, whei-e it is very narrow ; it then enlarges slightly, and is produced

beyond the fin at its apex {ap.2)rol.) very much as in Cheiroteuthis Ficteti, a species

CEPHALOPODA FEOM THE CALCUTTA MUSEUJM. 13

admirably described by M. Joubin (2). This apical jirolongation of the mantle is shorter

than in the latter species, and moreover is provided with a lateral fin on each side {ap-f.),

a character which distinguishes the present species at once from any hitherto described.

The mantle is laterally compressed, forming slight median longitudinal upper and lower

ridges. Dorsally the mantle-edge is produced in a point above the neck ; below it is

raised opposite the funnel. The fins are wide, the outlines of the right and left together

forming an almost perfect circle {f, fig. 51).

The funnel, provided with a large internal valve, is fixed to the head without distinct

bridles, and at its posterior edge carries two sockets, each possessing two prominent lobes

fitting into corresponding depressions in the mantle (fig. 56, a Sc h).

The head is small ; the eyes moderately large and without sinus. About halfway

between each eye and the attachment of the si2)hon is an olfactory jjapilla {olf.p.), about

2 mm. in length. The buccal membrane is well developed, with seven lobes and ridges.

The mandibles are very sharp (fig. 54, a & h) ; the ujiper mandible has a basal tooth on

either side {bt., fig. 54^), corresponding to which are small teeth on the lower mandible.

The radula consists of seven rows of teeth (fig. 57), closely resembling those of C. Picteti,

Joubin (2).

All the arms are somewhat square in section, and are provided along the upper and

outer edge with a membrane very narrow in the first two pairs, absent in the third, and

very broad in the fourth (;«). The third and fourth pairs have narrow membranes along

the lower and outer edge *.

Two rows of small suckers are placed rather far apart along each arm (rather more

closely set on the dorsal than on the ventral arms). Each sucker is obliquely set on a

slender stalk, and has a narrow opening, the horny ring of which is armed on the distal

side with square teeth (fig. 55). The soft rim of the sucker is more or less raised uj)

into a peak above the toothed horny margin (fig. 55). On the ventral arms, at the base

of the outer row of suckers are convex pigmented patches, no doubt similar to the

" vesicules refringentes " described by Joubin in Ch. Veranyi (3).

The tentacular arms, which have unfortunately lost their clubs, are long and slender,

bearing at intervals the modified flattened suckers characteristic of the genus.

The pen was somewhat injured owing to the contraction of the mantle. It is very

long and narrow (fig. 52, a & h) ; the hollow cone reaches halfway up and opens by an

oblique aperture. Diagrams of transverse sections of the cone and of the anterior region

are given in figure 53, a & h. The pen thus closely resembles that of Ch. lacertosa,

described by Verrill (9), and of Ch. Picteti ; yet the portion in front of the cone is

not tubular, as figured by Joubin for the latter species Ch. Vei'anyi, on the other

hand, has hitherto been described, by d'Orbigny and Ferussac (5), and by Verany (8),

as possessing a pen flattened and expanded at both ends. On examining a siDecimen

from the Mediterranean, I find, however, that its pen resembles in every essential that

of Ch. macrosoma here figured ; in the case of the works referred to, the artist probably

flattened out the slender cone before drawing it.

* These membranes correspond rather to the keels in other forms, as they do not spring directly from the

sucker-bearing surface of the arm.

14 ME. E. S. GOODRICH ON A COLLECTION OF

Of the four species * of Cheiroteuthis hitherto known, two come from the Atlantic,

one from the Mediterranean, and one from Aniboyna. In general shajoe and size the

present species approaches most nearly the latter, Ch. Picteti ; yet it differs from it in

the possession of a fin along the apical region of the mantle, in the beak, horny ring of

the suckers, socket at the base of the siphon, and pen.

f

Cheiroteuthis pellucida, n. sp. (PI. 4. figs. 58, 59, 60, & 61.)

This small specimen, cajitured at a depth of 922 fathoms off the Vizagapatam coast,

lat. 16" 11' 15" N., long. 82° 30' 30" E., was brought up alive on deck, when it appeared

transparent, with dark purple chromatophores. In spirit it is still remarkably trans-

parent, and the chromatophores (not represented in fig. 58) are very large and few in

nixmber, scattered at wide intervals over the body, fins, and arms.

Tlie principal measurements are as follows : —

Length of the mantle (lower surface) 4*8 eentim.

Breadth „ '8 „

Length „ to sudden constriction . . 2'G „

„ „ beyond fin 'G ,,

,, of fin-attachment 2'1 .,

Breadth of fin 1-8

Length from mantle-edge to base of arms . . . 2.2 „

Breadth across eyes -7 „

Length of dorsal arm 1-4 „

„ dorso-lateral arm 1'8 „

„ ventro-lateral „ 2"3 „

„ ventral „ 4'5 „

,, tentacular ,, 8 „

>, ,> club 3

In general appearance this interesting little Cheiroteuthis reminds us strongly of

Doratopsis vermiciilaris (Riippell) by its long and almost cylindrical mantle with a

narrow apex, its long thick neck, and the great disparity in size between the ventral and

remaining three pairs of arms.

The mantle, as already mentioned, is nearly cylindrical until it suddenly narrows

down in the region of the fins to a narrow straight prolongation, which extends beyond

the fins, forming a rounded spine (fig. 58). The fins themselves are broad and rounded (/),

but the outline is less circular than in the preceding species. Dorsally the mantle

projects over the neck in a small point.

The fiinnel is sharply recurved at its apex, and provided internally with a broad valve

produced and thickened at the sides. The socket of attachment is shown in fig. 59.

The head is hardly wider than the neck ; the eyes are somewhat prominent. Between

these and the siphon are two olfactory papillae (olf.p.). The buccal membrane is

furnished with seven well-marked ridges and lobes.

Beyond the eyes the head narrows considerably, and enlarges again to support the

*

M. Joubin has lately described a new species from the Atlantic (4).

CEPHALOPODA EfiOM THE CALCUTTA MUSEUM. 15

arms. The three small and dorsal pairs of arms bear two rows of suckers, aud have no

lateral membrane. The large ventral arms have a membrane on the upper side ; toward,

the base they bear two rows of suckers, but about halfway up the suckers come to

alternate in so nearly the same sti*aight line that there appeal's here to be only one row.

The horny ring of the suckers (fig. 60) is armed mth rounded teeth on the proximal,

and powerful sharp teeth on its distal side.

The tentacular arms are comparatively short, and provided at intervals with numerous

flattened suckers. The long clubs bear four rows of small suckers, the outer row of

which has the longest stalks. Round the margin of the club is a ribbed lateral

membrane ; the apex ends in thickened, deeply pigmented, aud somewhat spoon-shaped

knob. The horny ring of the suckers has a wide papillary area bearing sharp teeth,

and characteristically notched on its distal border ; the proximal margin of the ring is

smooth, the distal margin armed with powerful sharp teeth (fig. 61).

I have not dissected out the pen ; it appears to closely resemble that of the foregoing

species.

Although, as the description shows, this specimen closely resembles JDoratopsis, yet

the structui'e of the tentacular arms shows that it undoubtedly belongs to the genus

Cheiroteutliis.

HiSTiOPSis HoTLEi, n. sp. (PI. 4. figs. 62, 63, 64, 65, 66, 67, 68, 69, 70, & 71.)

One specimen captured near the Andamans, at a depth of 190 fathoms.

Length of mantle to notch between fins (upper surface) . 2"2 ceutim.

„ „ to apex (lower surface) 1-9 „

Breadth ,, 1'2 ,,

Length of fin-attachment to posterior notch "6 „

,, fin beyond mantle-apex -'i ,,

„ combined fins 1"3 „

„ dorsal arm (riglit) 3"5 centim. (left) 3"3 centim.

„ dorso-lateral arm „ 3*4- „ „ 3*7 „

„ ventro-lateral ,, „ 3-1 „ „ 3'-i „

„ ventral „ „ 3 „ „ 3-2 „

„ tentacular „ „ 7 „

„ pen 2'1 centim.

Breadth of ,, -6 „

The mantle swells out slightly midway, then tapers to a blunt point (figs. 62 & 66),

Dorsally it projects above the neck ; the lower m.argin is nearly straight. The fins are

rounded, joined distally above the mantle-apex, beyond which they project.

The funnel is strongly recurved {si., fig. 68); the two lips which bound its aperture

are so applied to each other as to leave a narrow U -shaped opening. The sockets at the

base of the funnel are I -shaped {so.) ; two small bridles bind it to the head. Inside we

find a small valve prolonged into the upper portion of the ' funnel-organ,' which covers

the upper or attached Avall of the siphon, and into which fit two rounded flaps fixed on

either side to the lower or free wall of the siphon. The whole arrangement closely

16 ME. E. S. GOODEICH ON A COLLECTION OF

resembles that described and figvired below in Taonius abysslcola. Mr. Hoyle makes no

mention of the ' funnel-organ' in liis species (i).

The head is wide and sharply marked off from the narrow neck. Below each eye is

an olfactory papilla {plf.j}., fig. 64).

The eyes are large, with widely open eyelids (figs. 62 & 64) ; the left eye is injured

and protrudes from the eyelid, it has been restored in the figure.

The arms, which differ somewhat in length on the right and left sides, appear to be

in the following order of length : 2, 1, 3, 4. Unlike H. atlantlca of Hoyle, the web at

the base of the arm is quite rudimentary (fig. 63). The small suckers, placed in two

rows on all the arms, are of a peculiar conical shape (figs. 69 & 70), with a wide opening

furnished with a narrow horny ring armed round its margin with small sharp teeth.

The left and only complete tentacle enlarges at its extremity into a small club

(figs. 62 & 65), bearing four regular rows of small suckers on its distal half, and as many

as six irregular rows on its proximal half. At the widest region of the club the central

suckers attain a large size (fig. 65). They have round shallow cups, set almost straight

on short thick stalks (fig. 67) ; the margin of the horny ring is armed with numerous

long straight pointed teeth. Near the base there is a connective apparatus consisting of

a row of three alternating suckers and tubercles {c.app., fig. 65) ; two or three small

suckers arc scattered down the stem.

The buccal membrane has seven lobes, with corresponding ridges extending on to the

arms, as shown in figure 63.

The delicate little pen is lanceolate (fig. 71).

The colour of this specimen in spirit is pale yellowish-brown, covered with dark

purplish-brown chromatophores, on the mantle, iipper surface of the fins, head, buccal

membrane, and arms (especially on their iianer surface).

As seen in the figiu'e, a large niimber of U-shaped pigmented organs, most probably

phosphorescent (see Joubin, 3 & 4 a), are scattered in irregular transverse rows on the

lower sm-face of the mantle, head, and arms ; a few extend over to the upper surface,

and one row surrounds each eye (fig. 64). The first three pairs of arms have one row

each extending to their tips, whilst the larger ventral arms have three rows proximally,

reduced to two distally.

The exact systematic position of this little Cephalopod is not very easy to determine.

I have placed it provisionally in the genus Histiopsis of Hoyle, from whose specimen it

differs in the absence of a distinct web at the base of the arms, in the horny rings of the

suckers, in the buccal membrane, in the contimiation of the fins beyond the mantle-

apex, in the possession of one row only of pigmented organs on the first three pairs

arms, and perhaps in the presence of the ' funnel-organ ' (Verrill's organ).

The horny rings of the tentaciilar suckers arc very like those oillistioteuthis, to which

genus it is no doubt closely related.

Calliteuthis eeveesa, Verrill.

One specimen of this widely distribvited species was caught in the Andaman Sea at a

depth of 265 fathoms.

CEPHALOPODA FROM THE CALCUTTA MUSEUM. 17

Taonius abtssicola, n. sp. (PI. 5. figs. 72, 73, 71^, 75, 76, 77, 78, 79, & 80.)

Two sj)ecimens from the Laccadive Sea belong to this genus. The first, the large

specimen shown in figure 72, comes from a depth of 902 fathoms. It is somewhat

injiu*ed ; the skin has been rubbed off the mantle, fins, and head, and the eyes have burst

out of their lids. The second specimen, from a depth of 1370 fathoms, is very much

smaller and in a less satisfactory state of preservation.

The principal measurements of the large specimen are as follows : —

Length of mantle (lowei- surface) 7*6 centim.

Breadth „ near edge 3-8 „

Length of fin-attachment 2*4 „

Breadth across combined fins l-~ ^^

„ of head between eyes '7 „

„ across eyes 2'8 „

Length of dorsal arm 2'5 ,,

„ dorso-lateral arm 2'8 ,,

„ ventro-lateral „ 3"3 „

„ ventral „ 2-8 „

„ tentacular „ 4'2 ,,

„ >, club 1-1 ,,

The mantle is loose, enclosing an ample cavity ; it diminishes gradually to the origin

of the fin, and then suddenly to the narrow apex. The outline of the fins is egg-shaped.

The mantle is attached by a lozenge-shaped cartilaginous plate to the back of the neck,

and on both sides to the base of the siphon.

The aperture of the funnel is covered by the sharply recurved upper lip (fig. 72), All

previous observers have described the funnel of this species as destitute of valve.* On

slitting up the funnel of this specimen and turning aside the two sides as shown in

figui-e 7i, I found that the inner and upper wall is sharply bent inwards near the opening

so as to form a deep pit w^here the sij)hon is fused to the head. On either side of this

pit are the two cushions [c) noticed by Verrill (9), which in their normal position

almost close u.p the lumen of the funnel. When these two cushions are pushed aside, a

well-developed valve is disclosed rising from the bottom of the pit (fig. 74 v.). Behind

the cushions, further down the funnel, are two triangular flaps, flattened and fastened

by their base to the sides of the funnel {t.Jl., fig. 7i) ; they appear to be of a glandular

nature, and probably correspond to the lateral pads described in other forms by

AVeiss (10).

On the inner and upper wall of the siphon is a wide A-shaped plate — the funnel-organ

— very similar in shape to that figured by Weiss in Verania sicula. In the present

instance it was so loosely attaclied that it readily came off; it is represented in flgtire 75,

and its position is indicated by a dotted line in figure 74i. On the inner surface this

plate is produced on either side into a triangular cap {i.e.), which fits closely as a glove

* Since this was written M. Joubin (4) has described a small valve in the siphon of a new species of Taonius

from the Atlantic.

SECOND SERIES. — ZOOLOGY, VOL. VII. 3

IS -MR. E. S. GOODEICH ON A COLLECTION OF

on to the flaps already described lying opposite them.* I have confirmed these

observations on the second specimen.

Contrary to Verrill's observations in two other species (9), I find on either side

between the eye and the funnel a truncated olfactory papilla (fig. 76). It is slightly

expanded and flattened distally, the flat oblique surface being concave.

The head appears to have been narrow. The two eyes are very large and protrude

from their sockets.

The arms are thick, and of considerable length for this genus. The three dorsal pairs

are provided on both sides with a well-developed lateral membrane (largest in the third

pair), springing from the inner edge and supported by muscular thickenings arising

from the base of each sucker (fig. 73). The ventral arms are also provided with such a

membrane on the lower edge ; but it is rudimentary on the upper side, where on the

contrary the outer edge of the arm is produced into a lateral keel. On all the arms we

find two rows of suckers, largest on the third pair. The suckers (figs. 77, 78), very

obliquely set on a short stalk, have a wide opening provided with a horny ring, armed on

the distal margin only with about 14 squarish teeth. The papillary area is narrow.

The tentacular arms are thick- stemmed, the clubs only slightly enlarged and bearing

a lateral membrane on either side similar to that of the arms. The suckers of the club

are compressed and considerably injured in this specimen ; they appear to be set in

four rows, and of a peculiar conical shape (fig. 80). The stalk of the sucker sw^ells

gradually to the base of the cup, where there is a thickened ridge ; it then narrows and

expands again into a bell-shaped cwp, with an oblique opening. The margin of the

horny ring is armed with eight or nine strong curved teeth, extending round the distal

two-thirds of the circumference. The striated outer margin is frayed out into a fringe,

but this is probably artificial. From the club extending down the stem are small short-

stalked round suckers, the horny margin of which is armed all rovmd with blunt teeth

(fig. 79). Distally at the base of the club these suckers are placed in four rows, which

dwindle gradually to two rows proximally, where the suckers are very small and set in

pairs on either side of a median groove.

The buccal membrane has seven ridges ; the lobes are indistinctly marked.

Purplish-brown chromatophores colour the fragments of skin adhering to the head

and arms, the lateral membranes between the ridges, and the buccal membrane.

The pen can be seen, wdthout dissection, as a narrow ridge starting from the nuchal

]ilate and exjianding posteriorly into a thin plate, narrowing again to form a slender

cone, as figured by Pfefi'er for Taonius {Ilegalocranchia) maximns (6).

The second specimen is very much smaller, and is possibly a young individual of the

same species ; it is, however, not in a sufficiently good state of preservation to allow one

to make certain of its specific identity.

* In their normal position the jioints of the flaps are directed away from the middle line ; in figure 74 they

iirc directed inwards owing to the stretching open of the funnel.

CEPHALOPODA FEOM THE CALCUTTA MUSEU.AI. 19

OCTOPODA.

Family PTEEOTI.

ClKRHOTEUTHIS PACIFICA, Hoyle ?

A small and mutilated specimen, captured at a depth of 265 fathoms iu the Audamau

Sea, has been referred to this species.

Family OCTOPODIDiE.*

Octopus vuiiGABis, Lam.

One large female from the Andamans, and one smaller male from Point Galle, Ceylon.

These specimens resemble very closely our common Octopod, and I could find no

important distinction between the European and Indian forms.

Octopus granulatus, Lam.

Eleven specimens have been placed in this species. Three come from Port Blair, three

from the Andamans, one from Great Cocos Island, one from Bombay, two from the

Southern portion of the Malacca Straits, and one from Maskat in Arabia.

Octopus globosus, AppeUof. (PI. 5. fig. 81.)

One specimen from the Nicobars, one from the Kabusa Islands (Mergui Archip.), five

from the Southern jiortion of the Malacca Straits, three from Bombay, and one from

Point Galle, Ceylon — in all eleven specimens have been referred to this species. The

extremity of the hectocotylized arm of a male is shown in figure 81.

Octopus pictus (Brock), ^SbV.fasciata, Hoyle. (PI. 5. fig. 82.)

One male specimen from Port Jackson, Avhich agrees very closely with the specimen

described by Hoyle in the 'Challenger' BejDort. The extremity of the hectocotylized

arm, however, shown in fig. 82, difiers considerably from that described by Hoyle in

Oct. maculosus (Proc. U. Phys. Soc. Edinb. vol. viii. 1883), w^hich he considers to be the

same species. It seems probable that the var. fasciata may have to be separated as a

distinct species.

Octopus Januarii, Stp.

Three specimens appear to belong to this widely distributed and abyssal species. One,

a female, comes from a depth of 193 fathoms in the Bay of Bengal (lat. 20° 17' 80" N.,

long. 88° 30' E.) ; the othei- two are males captured at a depth of 271 fathoms in the

Andaman Sea.

The ridges on the hectocotylized tip of the arm in the male are more marked than in

the figure given by Hoyle in the 'Challenger' Report (i), but in aU essential respects

these specimens agree with his description.

* I must express my thanks to Mr. W. E. Hoyle for kiudly cxaminiug some of these Octopods.

3*

20 ME. E. S. GOODEICH ON A COLLECTION OP

Octopus macropus, Risso.

With considerable doubt eight specimens have been referred to this species. Seven

come from the Andaman Islands (three from Port Blair) and one from the Malacca Straits.

Octopus aculeatus, d'Orb.

Ten specimens from the Andaman Islands (six from Port Blair), one from Colombo,

and one from Little Cocos Island. It is with some doubt that these have been placed in

this species, wliich is not very thoroughly defined.

Octopus levis, Hoyle ?

One female specimen from Gopalpur, at a depth of 7 fathoms, has been provisionally

placed in this species. It agrees closely, although not perfectly, with Hoyle's description.

Octopus microphthalmus, n. sp. (PI. 5. figs. 83, 84.)

One female specimen from Port Blair, Andaman Islands (fig. 83).

This species is remarkable from the smooth cylindrical shape of the head and mantle,

the eyes forming no prominence wliatever on the surface of the head. Tlie mantle ends

obtiisely, and fits closely on to tlie head ; the mantle-opening, which is very narrow,

reaches rather more than halfway from the siphon to the eye. The aperture of the

eyelid is small. The funnel reaches to within 4 mm. of the edge of the web between the

ventral arms ; it is attached to the lower su.rface of the head along almost its entire

length. Tlie arms are rounded, and l)ear small somewhat conical suckers, which are

arranged some distance apart. Although they are placed in two rows, the suckers are

situated in zigzag fashion so as to approximate to the condition found in Eledone, for

instance, where they are in one row. The mandibles are dark and strong (fig. 84, a Scb).

The following are the princij)al measurements : —

Length of mantle and head to lower edge of web between ventral arms . . 4'5 centim.

,, „ to mantle-edge 2"7

Breadth of mantle 2

„ head across eyes 1*5

Length of dorsal arm 8'6

, dorso-lateral arm 8'1

„ ventro-lateral ,, 6'9

„ ventral „ G'9

There is a small web at the base of the arms, reaching 1-6 cm. from the mouth between

the dorsal arms, where it is longest (the inner surface of this web is the same between

the bases of all the arms).

The colour is yellowish -brown, inclining to dark brown on the upper surface of the

mantle, head, and outer surface of the arms.

CEPHALOPODA FEOM THE CALCUTTA MUSEUM.

.21

TAst of Works referred to in the Text.

1. HoYLE, W. E. — Challenger Reports, vol. xvi., pt. 4i, "Report on the Cephalopoda/' 188G.

2. JouBiN, L. — " Cephalopodes d'Amboine." Revue de Zool. Suisse, vol. ii., 1894.

3. JouBiN, L. — " Quclques organes colores, etc." Mem. Soc. Zool. de France, vol. vi., 1893.

4. JouBiN, L. — "Resultats des Campagnes Scieutifiques de Prince de Monaco": fasc. ix., 1895.

4fi!. JouBiN, L. — "Note sur I'appareil photogene d'uu Cephalopode." C. R. Soc. Biol. vol. v., 1893.

5. D'Orbigny, a., et Ferussac. — Hist. Nat. des Cephalopodes acetabuliferes. Paris, 1835-48.

6. PfEFFER, G. — " Die Cephalopoden des Hamburger Nat. Mus." Abhandl. d. Naturw. Ver.

Hamburg, Bd. 8, 1884.

7. Steenstrup, J. — " Hectocotyldannelsen, itc." K. Danske Vid. Selsk. Skriv., Rk. 5, Bd. 4, 1856.

Transl., Ann. Mag. Nat. Hist. ser. 2, vol. xx., 1857.

8. Vkrany, J. B. — Cephalopodes de la Mediterranee. Giines, 1851.

9. Verrill, A. E.— "Ccphalopods of the N.E. Coast of America." Trans. Conn. Acad. vol. v., 1880*

and vol. vi., 1884.

lo. Weiss, E. — " On some Oigopsid Cuttle-fishes." Quart. Journ. Micr. Sci. vol. xxix., 1888.

REFERENCE LETTERS.

22 ME. E. S. GOODEICH ON A COLLECTION OF

EXPLANATION OF THE PLATES.

Plate 1.

Inioteuthis maculosa, n. sp.

Fig. 1. View of lower surface, nat. size.

2. Enlarged view of the horny ring of a tentacular sucker.

3. Enlarged side view of a tentacular sucker.

Sepia singalensis, n. sp.

Fig. 4. Outline of the mantle and fins, and figure of the pen (inner surface), nat. size.

5. Enlarged view of a spermatophore.

6. Upper {b) and lower (a) mandibles, nat. size.

7. Enlarged view of a portion of the horny ring of a small tentacular sucker.

8. Horny ring of a small sucker of an arm.

Sepioteuthis indica, n. sp.

Fig. 9. Outline of the mantle and fins, reduced.

10. Figure of the pen of another specimen, reduced.

IL Enlarged view of a portion of the horny ring of an apical sucker of the tentacular club.

12. Enlarged view of the apex of the tentacular club.

13. Side view of the head, showing the olfactory fold, nat. size.

14. Upper (6) and lower (a) mandibles, nat. size.

15. Horny ring of a sucker of the buccal membrane, enlarged.

16. Portion of the left 4th arm of a male, enlarged.

17. Edge of the horny ring of a sucker of the 3rd arm, enlarged.

18. Large tentacular sucker, x 4 diam.

19. Portion of the edge of the horny ring of tentacular sucker, enlarged.

Plate 2.

Loligo indica, Pfeffer.

Fig. 20. Edge of the horny ring of an arm-sucker of a male, enlarged.

21. Horny ring of a sucker of the buccal membrane, enlarged.

22. Lower view of the left 4th arm of a male, showing the hectocotylization, nat. size.

23. Portion of the hectocotylized region of the same, inner view enlarged.

24. Horny ring of a small tentacular sucker, enlarged.

25. Enlarged view of a portion of the horny ring of an apical sucker of the tentacular club.

26. Horny edge of an arm-sucker of a female, enlarged.

27. Enlarged view of a portion of a large tentacular sucker of the same.

28. Enlarged view of a spermatophore.

CEPHALOPODA FROM THE CALCUTTA MUSEUM, 23

Loliolus Investigatoris, u. sp.

Fig. 29. Upper view of a male, uat. size.

30. Outline lower view of the mantle and fins, nat. size.

31. Upper view of the pen, nat. size.

32. Lower view of the hectocotylized 4th left arm, uat. size.

33. Enlarged inner view of a portion of the same.

34. Enlarged views of the upper [b) and lower [a) mandibles.

35. Horny ring of a tentacular sucker, enlarged.

36. Side-view of an arm-sucker, enlarged.

37. Edge of the horny ring of the same, enlarged.

Abralia andainanica, n. sp.

Fig. 38. Lower view, nat. size.

39. Outline upper view of mantle and fins, nat. size.

40. Enlarged view of the tentacular club.

41. Upper («) and side (6) views of the pen of a smaller specimeUj nat. size.

42 & 43. Front and side views of an arm-sucker, enlarged.

44&45. Front and side views of a tentacular suckei', enlarged.

Plate 3.

Abralia lineata, n. sp.

Fig. 46. Upper view, nat. size.

47. Lower view, enlarged.

48. Enlarged view of the tentacular club.

49. Horny ring of an arm-sucker, enlarged.

50. Horny ring of a tentacular sucker, enlarged.

Cheiroteuthis macrosoma, n. sp.

Fig. 51. Lower view, nat. size.

52. LTpper («) and side (6) views of pen, nat. size.

53. Diagram of a section of pen across anterior region (6) and cone («), enlarged.

54. Upper (6) and lower [a] mandibles, nat. size.

55. Sucker of the ventral arm, enlarged.

56. Socket («) at the base of the siphon, and cushion on the mantle {b), uat. size.

57. Teeth of the radula, enlarged.

Plate 4.

Cheiroteuthis pellucida , n. sp.

Fig. 58. Lower view, nat. size.

59. Socket at the base of the siphon, enlarged.

60. Sucker of the arm, enlarged.

61. Tentacular sucker, enlarged.

24 ■ ON CEPHALOPODA FEOM THE CALCUTTA MUSEUM.

Histiopsis Hoylei, n. sp.

Fig. 62. Lower view, nat. size.

63. Enlarged view o£ the mouth, buccal membrane, and the base of the arms.

64. Enlarged view of the right side o£ the head.

65. Enlarged view of the tentacular club.

66. Upper view in outline of the mantle and fins, nat. size.

67. Enlarged side view of a large tentacular sucker.

68. Enlarged left-side view of the funnel and mantle-edge.

69 & 70. Enlarged side and front views of an arm-sucker.

71. Upper view of the pen, nat. size.

Plate 5.

Taonius abyssicola, n. sp.

Fig. 72. Lower view, nat. size.

73. Inner view of a portion of the dorsal arm, enlarged.

74. Enlarged view of the base of the head and siphon and mantle slit up along the median line and

turned aside.

75. Funnel-organ, lower view, removed from its place on the wall of the siphon, indicated by a

dotted line in fig. 74, enlarged.

76. Enlarged view of the olfactory papilla.

77. Side view of an arm-sucker, enlarged.

78. Horny ring of the same, enlarged.

79. Enlarged view of a portion of the horny ring of a small sucker at the base of the tentacular

club.

80. Front (a) and side (6) views of a tentacular sucker.

Octopus globosus, Appellof.

Fig. 81. Enlarged view of the extremity of the hectocotylized arm.

Octopm pictus (Brock), vax.fasciatus, Hoyle.

Fig. 82. Enlarged view of the extremity of the hectocotylized arm.

Octopus microphthalmus, n. sp.

Fig. 83. Lower view, nat. size.

84. Lower (a) and upper (6) mandibles, enlarged.

I

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LINNEAN SOCIETY OF LONDON.

MEMORANDA CONCEKNING THANSACTIONS.

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[VOL. VII. PART 2.

THE

(c^f/l.

ri^

IRANSACTIONS

16i/7

OF

THE LINNEAN SOCIETY OF LONDON,

AMPHIPODA FE(.)M THE COPENHAGEN MUSEUM AND OTHER SOURCES

BY

The Rev. THOMAS R. R. STEERING, M.A., F.R.S., F.L.S.

LONDON

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AND FRANCIS, RED LION COURT. FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY, W.,

AND BY LONGMANS. GREEN, AND CO., PATERNOSTER-ROW.

May 1897.

[ 25

II. Amphipoda from the Copenhagen Mmeiuii and other Sources. By the Rev.

Thomas R. R. Stebbing, M.A., F.H.S., F.L.S

(Plates 6-14.)

Head 19th November, 1896.

Introductom Remarks.

The Zoological Museum at Copenhagen is rich in Amphipoda. It is rich also in

living authorities on this group of Crustaceans, since Inspektor Dr. Meinert and Professor

Liitken are two of its Directors, and Dr. H. J. Hansen is on the staff. This might well

seem a happy concurrence of a fine collection in the hands of those well qualified to

make its value known to the world. But the masters in science find their work

continually expanding, while time remains remorselessly inelastic. Hence it is that

these gentlemen, being themselves beset by other duties, have passed over to me the

task of reporting on the Amphipoda of the Danish University.

In this first memoir on the subject some of the more striking rarities are described,

together with one or two of a less uncommon type. As the collection is not local but

cosmopolitan, the opportunity has been taken of bringing mto notice certain other new

or insufficiently known forms, in addition to those received from Denmark. For some

of these I am indebted to Professor W. A. Ilaswell, D.Sc, of Sydney, New South Wales,

and G. M. Thomson, Esq., E.L.S., of Dunedin, New Zealand. A specimen, which in

the Report on the ' Challenger ' Amphipoda was unavoidably presented without

adequate ceremony, and which in conseqiience subsequently became the subject of

misunderstanding, is now set forth with due illustration, and a specimen from the Clyde,

some years ago described without figures, now in like manner makes a more formal

appeal for acceptance as the representative of a valid species.

The range of the various specimens described extends from the shore to the deep sea,

from Cuba to Ceylon, from the North Atlantic to the South Pacific, from the western

coast of Scotland to the eastern coasts of Australia and New Zealand. Nine genera and

ten species are discussed. Six of each are new. The species afford an illustration of

two difficulties which not unfrequently arise in systematic natural history. Some of

them are so like their jireviously known neighbours that a short-sighted jierson might

think them not worth distinguishing. Others stand oddly apart, with so queer a combi-

nation of characters that more than one existing family must look at them askance,

imwilling to embrace, reluctant to repulse, in truth not very well able either " to do

with them or without them." Opinions will differ on the policy of promptly establishing

new families for eccentric forms, or of postponing that responsibility to as late a date as

SECOND SERIES. — ZOOLOGY, VOL. VII. i

26 EEV. T. E. E. STEBBING ON AMPHIPODA FEOM

possible. In the amiable endeavour to oblige the partisans of either view, I offer

tentatively a new family for one of these perplexing species, boldly assign one to an

old family, and leave one for the present homeless.

Fam. ORCHESTIID^.

Parhtale, n. g.

First cmtennce longer than the peduncle of the second.

First maxillm with the palp one-jointed, not extending beyond the distal margin of

the outer plate.

Max'illipeds with the palp four-jointed.

Both pairs of gnathopods subchelate, differing in the two sexes.

The third uropods carrying a minute inner ramus.

Telson bipartite.

The character of the Orchestiidse has to be slightly modified for the reception of this

genus, since in it the third uropods are not absolutely one-branched, but show a

sradation towards the more normal biramous condition.

Parhyale fascigek, n. sp. (Plate 6.)

Specimens in spirit are slightly iridescent. The skin has some minute setules

scattered over it. The second and third pleon-segments arc squared at the postero-

lateral angles. The fourth segment almost reaches to the telson, overlapping the

very short fifth segment, whUe the sixth is dorsally obsolete. The telson is divided

to the base, its two oblong or sometimes somewhat triangular leaves standing nearly

upright.

Eyes oval, dark, obliquely set near the top and fi'ont of the liead ; ocelli numerous.

First antennce. The second and third joints together approximately equal in length to

the much stouter first joint ; the flagellum of ten or eleven joints is longer than the

peduncle.

Second antennce. The last two joints of tlie peduncle nearly equal in length ; the

flagellum not once and a half as long as the peduncle, with about twenty joints in the

male and fourteen to sixteen in the feniale.

Upper lip. The apical margin is rounded and furred in the usual manner.

Mandibles. The cvitting-edge has six teeth. The secondary plate on the left mandible

is strong and quinquedentate, on the right it is slighter, with coml>like, slightly

concave edge ; the spine-row on the left attains the number of six spines, which have

the appearance of plumose sette ; the molar tubercle is strong, prominent, finely denti-

culate, with a hairy tuft at one corner, and a long feathered seta at the other. Above it

and a little in advance is the articulating process.

Lower Up. The lateral processes are short.

First maxillce. The inner plate is slender, surmounted by two feathered setse, of Avhich

the inner is the shorter. The outer plate is rather liroad, surmounted by nine spines

THE COPENHAGEN MUSEUM AND OTHEE SOUECES. 27

variously denticulate, in two rows, which are set so closely together that it is difficult

to count and discriminate the spines. The palp is slender, tipped with a minute hair

and small seta. There is often a slight constriction of the margins near the apex, as

though a second joint were being thought of.

Second maxillcc. The setae round the apex of the outer plate are longer than those of

the inner. The fringe on the inner plate is bounded by a seta conspicuously longer than

the rest.

MaxilUpeds. The inner plates have the usual setse and three apical teeth. The

outer plates reach but little beyond the first joint of the palp, and have their spinules

set a little Avithin the margin. Both the second and third joints of the palp are broadly

lobed at the inner distal extremity. The third joint has a little rounded and shining

process for the aj^ex of its outer margin. On the inner surface there is a graduated row

of spines, and in the male a dense tuft of setae on the outer surface, from among which

the sharjD curved finger projects. The inner margin of the finger carries some spinules

or small hairs.

First (jnuthopods. The side-plates are widened below, and have the front margin

straighter than the hinder one. The fifth joint is distally widened, and has the

projecting hind margin fringed with setae. The hand or sixth joint is as long as the

preceding, and in the male fully as wide, but narrower in the female. The hind margin

has a central fringe of setix', bounded by a slight contraction in the width of the hand.

The palm is rather oblique, fringed with little hairs and setules, and carrying two

unequal but stoutish spines at the extremity, against which the rather broad finger

impinges. There are spines on the inner surface of botli hand and wrist, and minute

hairs on the inner margin of the finger.

Second gnathopods. The side-plates are oblong, with rounded corners below, but with

the hind margin somewhat excavate above. The branchial vesicles of these limbs and

the four following pairs have at the base a small vesicle accompanying the ordinary large

one. The marsupial plates of the female are long, distally acute, and, at least in the

distal part, closely fringed. As in the first pair, the second joint widens distally, the

third is short, the fourth is of nearly uniform breadtli, Imt having the hind margin longer

than the front. The wrist in the male is almost triangular, with convex front border,

and behind masked by the fourth joint, whereas in the female it protrudes a spine-

fringed lobe between that joint and the hand. In the male the band is massive, with

very oblique palm, uniformly convex till near the distal end, bordered Avith nuniei'ous

little spines, over Avliich the long and broad finger closes tightly, sending its point

into a little pocket on the inner surface of the hand, from which arises a small group

of stoutish spines. The hind margin is almost smooth, but has a small indent similar

to that in the first pair. In the female the hand is less massive, but still much larger

than the Avrist, Avith a very oblique palm, leaving a shorter hind margin, Avhich is fringed

with spines. In both sexes the finger has little hairs set at right angles to the inner

margin.

First peraopods. The side-plates are a little broader than the preceding pair, but

similarly shaped. The fourth joint is longer and much broader than the fifth or sixth.

4*

28 EEV. T. R. E. STEBBING ON AMPHIPODA FEOM

The finger is short, curved, with a spinule from its inner margin cnrviug towards the

small but decided nail. The fingers are similarly shaped in all the perteopods.

Second perc^opods. The side-plates are broader than the preceding pairs, with the hind

margin doubly excavate above. The limbs closely resemble the preceding pair.

Third perceopods. The side-plates are broad, bilobed, not very deep. The second

joint has the breadth and depth about equal, with the margins very slightly indented.

The fourth joint is much broader, but not longer than the sixth, which is narrower but

a little longer than the fifth. The fourth joint has spines on both margins, the apical

groups l)eing large. The same applies to the fifth joint, except that its hind margin is

only armed at the apex. The sixth joint has spines along the front.

Fourth perceopods. These are similar to the preceding, but with the joints from the

second to the sixth decidedly larger.

Fifth 2JercBopods. Tlie side-plates are not bilobed. The limbs are like the jireceding

pair, but larger.

Fleopods. There are two, or in some cases three, small coupling-spines. The spines of

the inner margin of the first joint of the inner ramus have a distal thickening, but no

cleft could be distinguished. The rami appear to be as nearly as possible eqvial in

length, with about thirteen joints apiece, each carrying the usual pair of plumose setae.

TJropods. The first pair are the longest, with peduncle longer than the rami, having

spines on its iipper margin and a large spine at the apex. The rami are of equal length,

with one large and other small spines at the apex, the inner having two in addition on

the upper margin. The second pair are much shorter, but similarly armed. The third

pair are short, the peduncle not being so long as the telson. It carries some apical

spines. So does the outer ramus, Avhich is a little shorter. The inner ramus is conical,

almost rudimentary, tipped with a minute seta.

Lenyth. In the partially-folded position which seems natural to animals of this genus,

the length of the specimens averages a quarter of an inch.

ILah. Harbour, Antigua, West Indies (specimens received from W. E. Forrest, Esq.).

Specimens from the Copenhagen Museum were labelled " St. Thomas, Havnen, 1877.

Eggersr

The specific name refers to the appearance presented by the extremity of the maxil-

lipeds, whicli in the male is very striking.

Fam. LYSIANASSID^.

Lysianax cinghalensis, n. sp. (Plate 7 A.)

First three segments of plcon large, postero-lateral angles of third segment rounded.

The etjes large and black, occupying most of the svu-face of the head, on the top of

which they meet.

First antennce. First joint tumid, scarcely longer than deep, nearly twice as long as

the second and third combined ; flagellum six-jointed, shorter than first joint of peduncle ;

accessory flagellum three-jointed, less than half the length of the primary.

THE COPES^HAGEN MUSEUM AND OTHEK SOUECES. 29

Second antennm. In the male about two-thirds the length of the animal, the ultimate

joint of the peduncle considerably longer than the penultimate, flagellum of about thirty-

five slender joints.

Mouth-organs closely agreeing with the generic account given by Sars in ' The

Crustacea of Norway.' The slender mandibular palp has the first joint characteristically

elongate, and there are but few spines on the paljj of the first maxillae.

First gnathopods. The side-plates widened below, so that they are as wide as deep ;

the second joint as long as the four succeeding joints combined, the third larger than

the fourth, the fifth much wider but rather shorter than tlie narrow, taj)ering sixth ; the

finger curved, small.

Second gnathopods. The second and third joints slender and elongate, the fifth as long

as the third, the sixth more than half the length of the fifth, gradually widening distally,

with short transverse palm, on which the finger closes tightly, without overlapping it.

First and second permopods. The side-plates of the second pair are deeply and rather

widely excavate behind. The second joint of the limbs comparatively short ; the fourth,

fifth, and sixth joints rather long, with some plumose setae.

Third percBopods. The side-plates wider than deep, pretty evenly bilobed ; the second

joint as broad as long, smaller than the side-plates ; the fourth joint rather broad,

produced to an acute point.

Fourth and fifth perceopods. The second joint broader and much longer than in the

preceding paii", roundly produced behind.

Branchial vesicles strongly pleated.

TJropjods slender. First pair with the rami subequal, more than three-fourths as long

as the peduncle, each with three marginal spines. Second pair, with subequal rami,

almost as long as the pedimcle ; the outer ramus with four marginal spines, the inner

constricted near the end, with a spine in the notch. Third pair with the peduncle

longer than the rami, produced to a point at the outer angle ; the inner ramus a little

shorter than the outer, both with long setae on the inner margin.

Telson oval, not reaching far along the peduncle of the third uropods, having a

feathered setule on each lateral margin, and the apex smootlily rounded.

Length three-tenths of an inch.

Labelled " Trincomali (Ceylon), 3/89, surface. K. Fristedt," Copenhagen Museum.

Lysianax cubensis, u. sp. (Plate 7 B.)

Lateral angles of the head considerably produced, broadly rounded. Postero-lateral

angles of third pleon-segment quadrately rounded.

FJi/es reniform, moderately large.

First antenncB. First joint large, longer than deep, not very much longer than second

and third combined, neither of tliese being extremely short; flagellum six-jointed, shorter

than the peduncle ; accessory flagellum three-jointed, less than half the length of the

primary.

Second avtennce. Last two joints of the peduncle (in the female) subequal ; flagellum

broken.

30 EEV. T. R. R. STEBBING ON AMPHIPODA FROM

Mouth-organs of the character usual in the genus, but palp of first maxilla with the

apex rather Avide, carrying one little spine and six very distinct teeth.

First QRcdhopods. Side-plates widened below, deeper than Avide. The second joint

shorter than the four succeeding joints combined, the fifth rather stouter than the

tapering sixth and quite as long ; finger small.

Second gnathopods. The second and third joints rather long and slender, the fifth as

long as the third, the sixth much more than half as long as the fifth, at first gradually

but distally rather abruptly widened ; palm transverse, finger very small.

First and second prrtropods. Side-plates of the second pair broad, the excavation being

moderate in breadth and deptli. The joints of the limbs of moderate dimensions, fringed

with smooth setse or spines.

Third perccopods. Side-j^lates much wider than deep, the front lobe deeper than the

hinder. Second joint much wider than deep, almost as large as the side-plate, the fourth

joint little widened.

Fourth per mopods. Second joint longer than broad, front margin strongly bowed, hind

margin sinuous, fourtli joint scarcely widened.

Fifth perceopods. Second joint much larger than in the preceding pairs, very broad,

but rather longer than broad ; fourth joint scarcely widened.

Marsupial plates slender, branchial vesicles rather strongly pleated.

TJropods. First pair Avith the rami subequal, slender, carrying a few margmal spines,

somewhat shorter than the peduncle. Second pair shoi-ter than the first ; peduncle

scarcely as long as outer ramus, which lias four marginal spines ; inner ramiis slightly

shorter, stout, with two spines, then strongly constricted with a spine in the notch.

Third pair much shorter than second ; peduncle rather longer than the rami, with one

lateral margin running out into a point, the other notched near the middle, the rami

almost smooth, eqiial.

Tel son reaching little beyond the sides of the sixth pleon segment, little longer than

broad, boat-shaped, apex truncate.

Colour of specimen, in spirit, brownish. Length about three-tenths of an inch.

Specimen labelled " Zi/sianasscc aff". Paa en Reise til Cuba." Copenhagen Museum,

Studer Collection.

Fam. STEGOCEPHALIDiE.

AXDANIOTES, n. g.

Head wdth small rostrum. First segment of peragon the longest. Sixth segment of pleon

longer than the fourth or fifth. Each of the first three side-plates socketed in a groove

on the underside of that next succeeding ; the fourth very large, subequal in breadth and

depth, with a wide shallow excavation behind, overlapping the fifth and in part the sixth.

Eyes wanting. First antennse with very thick first joint ; flagellum tfipering, the first

joint A'cry long, longer than the remaining three combined ; the accessory flagellum small,

one-jointed, tipped Avith a long spine. Second antennae with the last joint of the

peduncle shorter than the penultimate, flagellum short. Epistoma carinate. U2:)per

THE COPENHAGEN MUSEUM AND OTHER SOUECES. 31

lip broader tlian deep, slightly bilobed. Lower lij) with the front lobes wide apart, not

larger than the hind lobes, and snrmonnted with a single spinule at the outer corner.

Mandililes a slightly sinnous oblong in shape, with straight smooth cutting-edge ; a

tooth-like accessory plate on tbe left * mandible. First maxilla? with inner plate rather

large, bordered with 7-11 long plumose setae ; outer plate moderately broad, carrying nine

slender spines and a tuft of setules ; the palp one-jointed, nearly reaching the end of the

outer plate, tipped with seven setae or slender spines. Second maxillae with inner plate

very broad, with a fringe of 18 or 19 setae, most of them plumose ; the outer jilate shorter

and greatly narrower, tipped with nine setae. Maxillipeds with inner plates very broad,

the apical margin sloping outward, with three little spine-teeth; the outer plates not

nearly reaching the end of the palp's second joint, fringed with 13 spine-teeth on the

inner margin ; the joints of the palp successively diminishing in size, the third and fourth

slender and small. Appendages of the perteon nearly as in Andania. Uropods with the

peduncles robust, much longer than the rami; both peduncles and rami successively

diminishing. In the male, outer ranuis of first pair thick, curved, smooth, inner rather

shorter, straight, slender, each with two marginal spinules ; rami of second pair slender,

smooth, subequal ; rami of third pair minute, the outer nearly twice as long as the inner,

with a tiny second joint. In the female all the rami slender ; those of the third pair- not

minute, subequal, nearly as long as the peduncles. Telson broadly oval, but ending

almost acutely, cleft nearly to the middle, but without any dehiscence, shorter than the

peduncles of the tliird uropods.

Andaniotes corptjlentus (Thomson). (Plate 8.)

1882. Anonyx corpulentus G. M. Thomson, Trans. New Zealand Institute, vol. xiv. p. 231, pi. 17.

figs. 1 a-f.

1888. Andania abijssorum Stabbing ' Challenger ' Amphipoda, p. 739, pi. 37.

1893. Stegocephalus abyssorum Delia Valle, Gammaiini, p. 629, pi. 59. fig. 38.

Head vdth lateral angles rounded and below them produced downward in long straight

triangular lobes hidden under the first side-plates, below which the mouth-organs of the

down-bent head are visible. Third pleon-segment with the postero-lateral angles

narrowly rounded, the dorsal line distally bent abruptly downward, having (in the male)

two little eminences below the bend, the distal margin somewhat squared ; the fourth

segment dorsally convex ; the fifth depressed ; the sixth long, dorsally convex, forming two

longitudinal eminences, between which the telson is concealed in a lateral view.

First antenncp. The third joint of the pedimcle is transversely oval ; the first joint of

the flagellum carries transparent filaments ; the setiform spine at the apex of the accessory

flagellum is longer than the joint.

Second antenme. The flagellum is eight-jointed.

First (inathopods. The side-plates are roughly triangular. The second joint is long

and broad, stronger in the male than in the female ; the third joint longer than broad ;

the fifth joint in the male longer and much wider, in the female wider but only little

* Not on the right, as stated in tlie ' Challenger " Arnphipoda, p. 739.

32 REV. T. R. E. STEBBING ON AMPHIPODA FROM

longer thau the sixth, with many setse on both margins, those in front elongate ; the

sixth joint abruptly narrows distally, so as to leave no palm, carrying long setse in front,

more in the male than in the female, and a row of shorter ones at right angles to the

hind margin ; the finger is small, curved.

Second gnatlioimds. The second joint is slender, curved at the base, the third longer

than the fourth, the fifth and sixth rather slender, subequal ; the curved finger impinging

against the sinuous hind margin of the sixth joint, which is armed with plumose setae.

Third jyerceopods. The second joint is scarcely dihxted ; the fourth is not very wide,

acutely outdrawn below.

Fourth i^erceopods. Second joint twice as broad as in the preceding pair, fourth joint

also larger.

Fifth perceopods. Second joint longer and much broader than in the preceding pair,

subequal in length to the rest of the limb, broadly overlapping the third joint ; the fourth

joint rather wide, but much shorter than in the preceding pairs.

Pleopods. Coupling-spines rather long.

Length nearly three-tenths of an inch.

Hub. New Zealand. A male and a female specimen received from G. M. Thomson,

Esq., F.L.S., the first describer of the species. A female specimen was also taken by the

' Challenger ' Expedition.

Earn. PHOXOCEPHALID^.

PONTHARPINIA, n. g.

1880. Urothoe Haswell, Proc. Linn. Soo. N. S. Wales, vol. iv. p. .^^o.

1891. Harpinia? Stebbing, Trans. Zool. Soo. London, vol. xiii. pt. 1, p. l.

Back very broad, tapering to the rostrum and telson. Third pleon-segment setose on

the lower hind margin. Eyes small, lateral, set rather far back. Eirst antennae with

first joint tumid, second more slender, setose, third short ; accessory flagellum many-

jointed, more than half as long as the primary. Second antennae with the basal joints

of the peduncle short and stout; the penultimate long, broad, and setose; the ultimate

much shorter and nai'rower, but also carrying long setae ; the flagellum shorter than

the peduncle. Upper lip distally rounded, wide. Lower lip quadrilobate. Mandililes

with cutting-] )late and left mandible's accessory plate small, divided into a few

teeth ; spine-row of 8-10 spines, the first on the right mandible conspicuously the

largest (perhaps representing the accessory plate) ; molar small, prominent, tipped with

a few imeqtml spinules ; palp much longer than the trunk of the mandible, third

joint rather shorter than second, Avith many long setae near the base and the apex.

Eirst maxillae : inner plate small, carrying three short setae, outer with eleven spines,

very slight in size and armature; second joint of palp with 4 spinules and 4 setules

on truncate apex. Second maxillse : inner j)late shorter and narrower than the outer,

its armature not occujiying more than half the inner margin. Maxillipeds with the

plates narrow and not very long ; the outer scarcely reaching the middle of the long and

broad second joint of the palp, fringed with half a score of graduated spines ; the fourth

THE COPENHAGEN MUSEUM AND OTHER SOUECES. 33

joint of the palp slender and curved, considerably longer than the third. Gnathopods

apparently varying in the two sexes. First and second j)erajopods with the fourth joint

much longer than the fifth or sixth ; fifth much wider than the sixth, fringed with long

spines at the hinder apex ; the finger small, spine-like, scarcely so large as a knife-like

spine on the apex of the sixth joint. Third and fourth peneopods with the second,

fourth, and fifth joints greatly widened ; fifth pair much smaller than the others, its

second joint much expanded, Avidest distally, produced to the end of the fifth joint ; third

joint wider than those folloAving, which are all narrow and small ; the finger straight,

acute. First uropods with a long spine at apex of peduncle, rami suhequal, rather

longer than peduncle, spinose ; second pair short, rami equal, one sjjinose ; third pair

with lanceolate rami. Telson divided into two suboval plates.

Marsupial plates of the female narrow.

The generic name is intended to indicate the intermediate character of this genus

between such forms as those in the genera Urothoe and Hailstorms of the Pontoporeiidte

and Harpinia in the Phoxoeephalidre. By the character of the mandibles it is better

placed in the latter family.

PoNTHARPiNiA PiNGUis (Haswell). (Plate 9B.)

1880. UrotJwe jnnffuis Haswell, Proc. Linii. Soc. N. S. Wales, vol. iv. p. 3.25, pi. 19. fig. 2.

1882. „ „ „ Catalogue of the Australian Stalk- and Sessile-eyed Crustacea, p. 240.

1891. Harpinia t jnngiiis Stebbing, Trans. Zool. Soc. London, vol. xiii. pt. 1, p. 4.

1893. Urolfioe irrostruta ? Delia Valle, Gammarini, p. 667.

Head long, tapering from a broad base. First side-plates tending to quadrate, but

widened below ; fourth with rounded lower margin, widest just below the shallow exca-

vation ; fifth broad, not deep, the binder lobe the deeper ; seventh very small. Third pleon-

segment with a very small produced point at the lower hinder angles, above which the

hind margin is finely serrulate. The fourth segment ajjpears dorsally to overlap the fifth

and sixth.

First antennce. Fhigellum consisting of 15 joints, accessory flagellum of 10 ; in a

female specimen of 9 and 7 respectively. A peculiarity of these joints is that the apical

margin being oblique, they overlap one another. This is shown in Haswell's figure of

the primary flagellum, though he does not mention it in his text.

Second antennce. Last joint of peduncle narrow at base, thence a little widening ;

flagellum in female with 10 joints, shaped as in the first pair. Haswell's figure shows

21 joints.

Tipper lip wider than deep. Lower lip with very small principal lobes.

The mouth-organs in general are small, except the palps of the mandibles and

maxillipeds.

Tirst gnathopods. 2 . Second joint reaching much beyond the side-plate ; fifth nearly

as long as second and rather wider, fusiform; sixth shorter and rather narrower, widening

from a narrow base, then preserving an almost iiniform width to the transverse slightly

convex palm, wliich ends in a short tooth, tlie convex front margin of the widened part

SECOND SEIIIES. — ZOOLOGT, VOL. VII. 5

Si EEV. T. K. K. STEBBING OX AMPHIPODA EKOM

li'ing-ed with many seta-like spiues ; the finger closely fits the palm and projects a very

little beyond it.

Second (jnathopods. S . Almost exactly like the first, but the sixth joint rather longer

and more slender, -with a smaller palmar tooth, and tlie finger not extending beyond the

palm. The marsupial plate is as long as the second joint but much narrower, while the

branchial vesicle is considerably longer and much wider ; the side-plate is oblong, m ith

the lower margin slightly convex, and like the side-plates in general partly fringed Avitli

setoe.

Gnathopods. 6 . The species now being described is assigned to Haswell's Urothoci

pinguis on the supposition that the account gi\en by Haswell refers to the male, and

that in that sex the gnathopods are strikingly different from those of the female.

Haswell's description says : — " Gnathopoda large ; anterior pair Avitli the carpus three-

fourths of tlie length of the propodos ; the propodos ovoid, swollen ; the palm not defined ;

the dactylos half as long as the propodos ; posterior pair longer than the anterior ; carpus

small, subtrian<];ular ; ]n'opodos ovate, palm defined by a prominent angle ; dactylos rather

more than half as long as the propodos."

Third pera'Ojjods. Second joint expanded, longer than broad, front margin sinuous,

serrulate, carrying slender spines and setoe, hind margiu smooth ; fourth joint broader

than long, with a long free upper margin armed with slender spines, hind margiu cut

into 5 teeth, this and the lower margin spinose; fifth joint narrower than fourth, but

still very broad, breadth and length equal, fringed with many spines and setai ; sixth

joint not longer, and less than half as broad ; finger quite small.

i^o^-;-;'/^ j>er^q2;o(/* similar to third, but larger ; second joint broader in proportion to

length; fourth very large and setose, with 7 teetli on hind margin, of Avhich the lowest

two are formed by deep incisions ; fifth joint rather longer than broad, about twice as

broad as the sixth.

Fiftliperceopods. The large expansion of the second joint has a smooth front margin, the

hind one serrate, the lower sei-rulate and fringed with sette ; the fifth joint is apically

finely pectinate; the finger is more than half the length of the sixth joint.

Pleopods. The peduncles are short; the rami with about 21 ratlier broad joints.

(Jropods. The rami of the first pair are slightly curved, each with a short stout nail ;

the rami of the second pair are straight ; those of the third pair (at least in the male)

lanceolate, long, plumose.

Telson with length and breadth equal, the apices rather divergent, each with a spinule

in a small emargination, the outer margins (in the male) setose.

Length of male yj inch, of female -^^ inch.

" Bondi, New South Wales, cast on the beach during a storm," is the source assigned

for the specimen described by Professor Haswell ; the specimen here described was

contained in a gathering from Jervis Bay, kindly forwarded to me by the same author.

THE COPENHAGEN MUSEUM AND OTHEE SOURCES. 35

Fam. LEUC0TH0IDJ3.

Leucothoe INCISA, Robertson. (Plato 10.)

1888. Leucotho'e farina Chcvreux (not Savigny), Bulletin do la Socirte cVetiulcs scientifiqucs de Paris,

W annee, U"' sem., Extr. p. 9.

1892. Leucothoe incisa Robertson, Transactions of the Natural History Society of Glasgow, vol. iii.

p. 217 (sep. copy, p. 23).

The drawings of this species were made many years ago, hut have waited till now for

a suitable opportunity for publication. The species of Leucotlioe axe se^iarated by rather

fine distinctions. In 18G0 Boeck named a new species LeucofJioe LiUjehorgii, hut in his

later works he was willing to let this lapse as a synonym of the long known Leiicolhoii

spinicarpiis (Abildgaard). In 18S9 Norman gave the name imparicornis to a form from

Shetland, which Sars in 1892 determines to be the same as 'Boeck's I/Hljcborffli,, the latter

name having priority. To tliis species, as figured and described by Sars, Leucothoe incisa

makes a tolerably close approximation, yet it seems difficult to unite the two. In hicisa

tlie fourth side-plates have the front angle rounded, not acute; the first gnathopods have

the tip of the process of the fifth joint strongly hooked, the inner margin of the hand not

quite smooth but faintly crenulate, and the finger not very small; in the second

gnathopods the ^^alm is convex and faintly but broadly crenulate, the finger is not

abruptly bent at the base ; the tclson, instead of being little longer than broad, is fully

twice as long as broad, with the apex almost acute. As in Lllljehorgil, the inner margin

of the wi'ist in the first gnathopods is serrate, and the postero-lateral angles of the third

pleon-segment are sharply upturned, forming a sinus with the bulging hind margin.

There is a tendencj^ to this in the preceding segment. The mandibles have the cutting-

edge divided into about eight teeth ; the secondary plate on the left mandil)le is large,

witli ten teeth, that on the right is much slighter (Sai's denies its existence in this genus) ;

the second joint of the palp is not much longer tlian the narro'^v^er third. In tli(> maxil-

lipeds the first and second joints of the palp have the length and breadth subequal.

Length not quite three-tenths of an inch.

Taken off Cumbrae, in the Clyde, at low water and also in 20 fathoms, by Dr. David

Robertson, LL.D., F.L.S.

Anamixis, n. g.

Head hood-like. Eirst side-plates small, three following pairs very large. Eyes well

developed. First antennae attached below tlie apex of the head, witli elongate peduncle

and no secondary flagellum. Second antennae remote from the first, shorter and thinner,

Avith small flagellum. Mouth-organs (at least in the adult) degraded and abnormal.

Maxillipeds Avith the full number of joints, the third simple. First gnathopods delicately

chelate ; second massive, complexly subchelate ; the other limbs slight, normal. Branchial

vesicles small, simple. Pleopods small. First and second uropods biramous, third at

present unknoAvn. Telson simple.

The shape of the head calls to mind the genus Bnlichia, the situation of the antennae

Plat ijiscUn opus, the size of the side-plates Metopa, themassiveness of the second gnatho-

pods Jlicrojjrotopus, the structure of both pairs of gnathopods and of the antenna) and

36 EEV. T. E. E. STEBBING ON AMPHIPODA FEOM

maxillijieds Lencotho'e. In reference to this combination of characters tlie name of the

genus has been chosen, from the Greek word ai'a^tgi?, mingling. Among existing families

it stands nearest to the Leucothoidse, l)ut the extraordinary nature of the mouth-organs —

whether due to a parasitic mode of life or to a marital stage of existence, or falling under

any other exiilauation — so far isolates the species now to be described that it may have

to be placed alone in a separate family, Anamixidae, which would for the present bear

the characters of the genus.

Anamixis Hanseni, n. sp. (Plate 11 )

The head is longer than any one of the perseon-segments, and is narrowed distally, Avith

rounded apex, with no distinct lateral angles. The second pleon-segment has the postero-

lateral angles acute, slightly produced ; those of the third are a little blunted. The fifth

segment is very short, scarcely distinguishable from the fourtli ; the sixth projects on

either side of the telson, in a way to suggest that the missing third pair of uropods may

be of a fairly large size.

The eyes are round, placed in the middle of the sides of the head, consisting of about

eighteen short ocelli.

First antenme. The first joint long and rather stout, the second nearly three-quarters

as long as the first, but much more slender, the third about two-fifths of the second ;

the flagellum eleven-jointed, a little longer than the first joint of the peduncle. A sensory

filament is present on several of the joints. These antennae dejiend from the head, being

inserted just below its apex.

Second antenntB. These are inserted at the other extremity of the head. The first

two joints arc very small, the third is little more than half as long as the first of the

upper antennae, the fourth is slightly longer than the second in the other pair, and the

lifth is a little longer than the third joint of its own pair. The slender flagellum is four-

iointed, less than half as long as the penultimate joint of the peduncle.

Mouth-organs. The underside of the head is slightly carinate, and apparently attached

to the keel there projects from between the second antennae a vertical plate, which may

be called the oral lamina. Its truncate front edge has some minute microscopic teeth.

With this curious and abnormal exception, no mouth-parts could be detected other than

the pediform maxillipeds.

Maxillqjcds. The second joint bulges slightly on the upper or inner side, while on

the outer or lower side it has a shallow cleft, between two smoothly rounded apices,

which just overlap the bases of tlie third joint. The third joint has no lobe or lamina,

but in appearance is the basal joint of a five-jointed palp. Of the actual palp the first and

second joints arc about equal in length, tlie second the wider, carrying some setse on the

lower margin, the third joint is longer than either of the preceding, armed with several

setue, and having its surface minutely furred. The fourth joint or finger is slender,

strongly curved, nearly as long as the third joint. Owing to the absence of j)lates from

the joints of the protopod the palps are in close contiguity. The appearance is rather

that of legs than of mouth-organs. In dissection the head came easily away, leaving the

maxillipeds very firmly attached to the first gnathopods.

THE COPENHAGEN MUSEUM AND OTHER SOURCES. 37

First gnathopods. The side-plates ave sinall, triangular, with the apex to the rear. The

second joint is slender, narrowest at tlie base. The small third joint is larger than the

fourth The fifth joint is very much Avider and much longer than the second joint. It

may he regarded rather as the hand tlian the wrist, its long and slender curved apical

proces«i, tipped Avith a slightly curved needle-like spine, forming the immovable finger

of the chela, while the sixth and seventh joints form the movable finger. The sixth

joint is slender, i-ather straighter than the process of the fifth, but otherwise very like it,

and tipped with a similar spine, which must be regarded as the seventh joint. It might

be sujiposed that tlie fifth joint in this remarkable form rejiresented a coalescence of the

wrist and liand, did not a com2)arison with the first gnathopods iu Leucotho'e make it

reasonably certain that the chela is composed in the way just described.

Second gnathopods. The side-plates are very large, rounded in front, produced beyond

the first segment. The second joint is narrow, distally somewhat widened, a little curved.

The third joint is of stouter build than usual, apparently articulating Avith all the three

folloAving joints. The fourtli joint is small, most of it lying flatly on the inner surface

of the fifth joint, with which it seems to be in coalescence. The fifth joint is subequal

to the second, liut In-oadest at its base and apically pointed. The hand is broad and

between three and four times as long as its breadth, the liind margin distally cut

into three teeth. The finger, more than half the length of the hand, has a curved

acute tip, and two slight projections on the inner margin. The complex clasjier is

formed by its impinging against the apex of the Avrist and the denticulations of the

hand. The peculiar arrangement of the third and fourth joints may be explained by

the extraordinary massiveness of tliese limbs and especially of the hand, Avliich is in

striking contrast to that of the preceding pair as well as to the general structure of the

other limbs.

First 2)erceopods. The side-plates are as deep as the preceding pair, but of much less

Avidth. The branchial vesicles are all of remarkably small size. The second joint

reaches a little beloAv the side-plate. Of the other joints the fourth is the widest, the fifth

is sliorter than the sixtli, tin; nail is slender and curved.

Second percBopods. The side-plates are rather Avider than the preceding paii-, with a

faint emargination at the farther end of the loAver margin and a very shallow excaA^ation

at the upper part of the hind margin. The limb differs but little from the preceding.

Third ferceopods. The side-plates are bilobed, Avith the hinder lobe the larger. The

second joint is not much longer than wide. The fourth joint has the hind margin

slightly produced. The rest of the limb is missing. The spiny armature in these and

the other limbs is insignificant.

Fourth per ceopods. The side-plates are lobed behind. The second and fourth joints are

rather larger than in the preceding and foUoAving pairs.

Fifth perceopods. The side-plates are small, rounded behind. The second joint is rather

more strongly spined along its front margin than is the case in the other limbs.

Fleopods. The rami are small, five- or six-jointed, shorter than the peduncles.

JJropods. The first pair are the longer. In both, the inner ramus is a little longer and

the outer considerably shorter than the peduncle. Tlic third pair are missing.

38 KEV. T. R. E. STEBBING ON AMPHTPODA FEOM

Telson. This is a little longer than broad. The broadly rounded apex does not reacli so

far back as the projecting points of the preceding segment, which are in turn overlapped

by the peduncles of the second uropods and these by the peduncles of the first pair.

The length of one specimen, with tail folded in, was less than a tenth of aa inch, of the

other rather more than a tenth.

Hab. West Indies. From Goniastrcea varia Dana.

The name is given in compliment to my friend, Dr. H. J. Hansen, the accomplished

naturalist by whom it was obtained.

Pam. PAEDALISCID^.

Pardaliscoides Stebl)ing.

1888. Pardaliscoides Stebbing, 'Challenger' Amphipoda, p. 1725.

1893. Pardalisca Delia Valic, Gammarini, p. 691.

Pirst antennae longer than second, second joint of the peduncle longer than the first,

both flagella many-jointed. Mandibles with broad cutting-edge ; tliat on the left side

having two blunt teeth above and two that are acute below, one of them small, the other

large, a rather broad accessory plate with crenulate edge, and two plumose spines ; that

on the right having a similar cutting-edge miuus the smaller acute tooth, no accessory

plate, but three plumose spines ; the three-jointed palp slender, fringed with setiform

spines. Pirst maxillte with one seta on the small inner plate, seven very unequal spines

on the inner plate, one of them plumose; the second joint of the j^alj) broad, with many

spinules about the apical margin. Second maxilbne with the plates slender, the outer

carrying three, the inner seven sctse. Maxillipeds with inner plates vei-y small, outer

plates short and narrow, fringed with spinules, the supporting joint not very large; j^alp

with first joint short, second robust and long, but scarcely longer than the third, the

finger long and slender with minute setules on the inner margin. Tlio tritiu-ating

organs (anterior lateral gastric lobes) are armed with six long spines. The gnathopods are

similar, simple, with the fifth joint robust, fusiform, the sixth and seventh slender, the

seventh fringed with minute setules. The peraiopods are slender, elongate. The second

uropods have the rami unequal, the third have the rami foliaceous. The telson is

deeply cleft.

Pardaliscoides tenelltjs Stebbing. (Plate 12.)

1888. Pardaliscoides teneUiis Stebbing 'Challenger' Amphipoda, p. 1~.'25.

1893. Pardalisca abtjssi Delia Valle, Gammaiini, p. G92.

Head with acute rostrum. There appears to be a small dorsal denticle on each of the

last two or three segments of the pleon.

First antenncB. The first joint stout, the third half the length of the second ; of the

flagellum thirteen joints remain, the first much the longest ; of the accessory flagellum

seven or eight joints remain, the first as long as that of the primary.

Second antennce. Last tAvo joints of the peduncle elongate, the last shorter than the

preceding; the flagellum half the length of the peduncle, twelve-jointed.

THE COPEXHAGEX MUSEUM AND OTHER SOUKCES. 39

Fh'st and second gnathopods. Tliere are numerous spines of vai'ious sizes on and near

the margins. On the hind margin of the wrist and hand, commencing at the narrowed

distal end of the wrist, is a series of short spines which are plumose. The setules on the

inner margin of the fingers are exceedingly small.

First and second perceopods. The fifth joint longer than the fourth or the sixth;

the second pair rather longer than the first, and further distinguished by having the hind

margin of the sixth joint fringed with about a dozen short blunt spines.

Third perceopods. Second joint very slightly expanded, fourth joint the longest ; finger

slender, acute.

Fourth perceopods like the third, but with rather longer joints.

Fifth perceopods considerably longer than the fourth, the second joint expanded above,

narrowing dovrnward, fourth joint very long. Branchial vesicle small, narrowly oval.

Telson much longer than broad, cleft thi-ee-fourths of the length, dehiscent, with a

spinule at each apex and a setule on each lateral margin.

Length not quite a third of an inch.

Kah. South Pacific, lat. 37° 29' S., long. 83° 7' W. Taken by H.M.S. ' Challenger,' in

tow-net at trawl, from a depth of 1775 fms.

Fam. EUSIRIDJi;.

EusiROPSis, n. g.

Head distinctly rostrate ; body Avithout dorsal projections ; side-plates of perteon

shallow. Antennte of male with calceoli on peduncle and flagelluui in both pairs ; first

antennae shorter than the second, secondary flagelluui one-jointed : the second antennae

of male with the last joint of the peduncle very elongate. Mouth-organs nearly as in

Eitsirus, but the mandibles have the molar feebly developed and the first maxillse have the

second joint of the palp narrower and scarcely longer than the first. Gnathopods nearly

as in Eitsirus, but with the backward projection of the carpus almost obsolete. Eirstand

second peraeopods slender, with the finger ending obtusely and tipped with long setoe.

The three following perajopods slender, elongate, plumose, with the fingers acute. The

uropods of the first two pairs with outer branch much shorter than inner, the third pair

very plumose in the male, the outer ramus shorter than the inner. The telson narrow,

apically incised.

EusiROPSis RiiSEi, n. sp. (Plates 13, 14.)

Head Avith triangular rostrum longer than broad ; second, third, and fourth the

shortest of the peraeon-segments ; first three segments of pleon large, with the postero-

lateral angles rounded, hind margin not serrate.

Eyes to all appearance entirely wanting.

First antennce. Eirst joint rather bulky, carrying eight tufts of setules on the lower

margin ; second joint rather shorter and much narrower than the first, with calceoli

along the lower margin ; third joint almost like a joint of the flagelluui ; the latter rather

40 REV. T. E. E. STEBBING ON AMPHIPODA FEOM

stout, carryiug a calceolus on each of tlie thirty-one joints rernainiug, the end being

broken ofT. The secondary flagelluin is minute and quite unobtrusive.

Second antennce. The first three joints very short ; the fourth stout, not so long as the

first of the upper antennae, furnished on the upper margin with nine tufts of setviles ; the

fifth slender, longer than the whole peduncle of the other pair, armed above with many

calceoli ; the flagellum longer than the peduncle; of the forty-two joints twenty-seven

carry each a calceolus on the upper side, the terminal fifteen, which are more slender and

elongate than most of the others, having each a sensory filament. It may be supposed

that the abundant armature of the antennse compensates the animal for its want of eyes.

Tipper lip. The apical margin is rounded, and the usual fringing moustache is

strongly developed.

Mandibles. As in the neighbouring genus Emirus the cutting-plate is scarcely dentate,

the secondary plate on the left mandible is quinque-dentate, on the right it is more spine-

like ; the spine-row contains five or six small spines ; the molar is very feeble and unob-

trvisive ; the second joint of the palp is robust, tlie third is narrower but rather longer,

fringed with many spinules.

Lower Up. The inner lobes are smaU.

First maxillie. The inner plate is feeble, short, and seemingly not armed with any

set£e ; the outer plate carries ten spines, of which the two outermost are the largest, the

rest are denticulate ; the palp has a stout first joint, but the second is weak and tapering,

scarcely longer than the first, tipped with five setfc.

Second maxillce. The inner plate is broader than the outer, but its apical armature is

shorter and very scanty.

Maxillipeds. The inner plates reach only to the base of the palp, and are not strongly

armed, but have the usual apical teeth ; the outer plates reach scarcely to the middle of

the palp's second joint, and are fringed with not numerous sctules. The palp's second

joint is broad and carries a conspicuous row of setae near the apex ; the third joint is

similarly armed ; and the finger, which is long and strong, has a few small setules on its

inner margin.

First gnathopods. The side-plates are very shallow, covering no part of the limb's

second joint. The fourth joint is subequal to the third, its broad apex reaching almost to

the base of the hand, and having the wrist attached to its front margin. The dista end

of the wrist is attached to the front margin of the hand, not to the side as might be

supposed from the drawings made from mounted and somewhat flattened dissections.

On the inner side of the wrist there is a small process, probably homologous with the

laro-e one in Eusirns which intervenes between the fourth joint and the base of the hand.

The hand is massive, distally widened, with long convex palm carrying setules, and

endin"- in a spinigerous pocket, into which the long curved finger inserts its tip.

Second ynathopods. The side-plates are shallow, longer above than below. The

branchial vesicles attached to these and the five following pairs of limbs have accessory

lobes. The joints of the second gnathopod show saircely any difference in shape from

those of the first.

First percBopods. The side-plates have a curious sort of axe-head shape, the front

THE COPENHAGEN MUSEUM AND OTHER SOURCES. 41

corner rounded, the hinder acutely produced. The whole limb is very slender, and, like

all the other perseopods, is adorned with long plumose setse. The second joint is

elongate, with four or five setoe on the hinder margin and two on the front. The fourth

joint has four setfe on the front margin; the fiftli has one on the front and two on the

hind margin ; the sixth, which is rather longer than either of the two preceding, has two

setae of great length on the hind margin and two or three on the front. The seventh

joint is not finger-like, less than half the length of the sixth, its apical margin not acute,

fringed with six ])lumose sette, mostly of great length.

Second perccopods. The side-plates are almost oblong, twice as long as deep, with the

upper margin slightly excavate. The limbs are in near agreement with the preceding

pair.

Third per(E02)ods. The side-plates are bilobed, the hinder lobe the deeper. The second

joint is ex23anded, rather deeply notched on the hind margin. The third joint is short.

The remaining joints are all very elongate, armed with numei'ous spines and long

plumose seta; on both margins, except in the case of the finger, which has the settc only

on the hind margin. The fourth, fiftli, and sixth joints are severally much longer

than the second, which is scarcely, if at all, longer than the straight acute finger.

Fourth percBopods. The hind lobe of the side-j)lates is rather long, the front one

evanescent. The limb is like that of the preceding pair, but with a larger second joint,

and the fifth decidedly shorter than the sixth.

Fifth percropods. The side-plates are not bilobed. ils already noticed, there are

branchial vesicles. Tlie second joint is rather longer than in the preceding pair, while

the fifth and sixth are not quite so long. As in the two preceding pairs, the setae fringing

the margins of the sixth joint are of great length, and the hinder apex carries a remark-

able tuft of these elongate appendages, which, together with those on the fingers, produce

a striking eff"ect.

Fleopods. There are three or four cleft spines on the first joint of the inner ramus,

this ramus consisting of seventeen joints, while the outer, which is slightly longer, has

nineteen.

TJrop>ods. In the first pair the peduncle is nearly as long as the inner ramus, and

carries some small plumose setaB on its outer, and spines on its inner margin. The outer

ramus is a little more than half the length of the inner. Both have many spines alouo-

the margins, those on the inner margin of the inner ramus being small but very close-

set. The peduncle of the second pair is about as long as the outer ramus, which is less

than half the length of the inner. These rami are armed as in the preceding j)air, which

they a little exceed in length. In the third pair the pedimcles rather exceed in length

those of the preceding pair. The outer ramus is a little shorter than the inner of tlie

second pair; it has spines at six points of the outer margin, and the inner fringed witli

spines and many long plumose setae. The inner ramus is rather longer than that of the

second pair, and is fringed on both margins with spines and long plumose setae.

Telsoii longer than the peduncles of the third m-opods, distally cleft for about a

quarter of its length ; a little way above the acute apices a notch on either outer margin

carries a long seta, and there is another a little higher up than the top of the cleft.

SECOND SERIES. — ZOOLOGY, VOL. VII. 6

42 EEV. T. E. E. STEBBING ON AMPHIPODA FEOM

Length, not including the antennae, in the slightly curved position of the sjiecimen

figured, two-fifths of an inch.

Hab. Tropical Atlantic. The label accompanying the specimen figured contained the

words " Eiisei 55. Stud. Sanil. ded. 1892." A second specimen, in less satisfactory

condition, was labelled " 22° N.B. 36° V.L. Hygom. Stud. Saml. ded. 1892." Copen-

hagen Museum.

The specific name was given in MS. by Professor Lutken in compliment to Herr

Riise.

Pam. undetermined.

Sancho, n. g.

liostral point small. Perseon depressed, very broad at the centre; fir.st segment

short, seventh unusually long. Pleon narrow, much of it flexed. Eyes on the top of

the head, separate. First antennae with principal flagellum longer than peduncle;

accessory flagellum small, one-jointed. Second antennse with last joint of peduncle

longer than the preceding joint. Upper lip not emarginate. Lower lip without inner

lobes. Mandibles Avith cutting-edge, accessory plate, and spine-row small, but molar

and three-jointed palp powerful. Pirst and second maxillae normal. Maxillipeds with

outer plates smaller than, and scarcely reaching beyond, the inner ; fourth joint of palp

small. Gnathopods subchelate, the first pair in both sexes feeble ; the second also feeble

in the female, but in the male very long with very bulky sixth joint. Pera^opods normal,

the fifth pair the longest. Second uropods with peduncle scarcely shorter and rami

much longer than those of the first, third with short peduncle but very long inner ramus;

in all three pairs the outer ramus is shorter than the inner. Telson short, triangular.

The name is taken from a character famous in fiction.

Sancho platynotus, n. sp. (Plate 9 A.)

The second and third pleon-segments have the postero-lateral angles minutely

produced ; at the second segment the pleon is bent and the remainder closely adpressed

to the ventral surface of the trunk.

Eyes round, separated by more than the diameter of either, composed of numerous

ocelli, of which those of the outer ring appear to be larger than the rest. Specimens

preserved in spirit have a light pinkish pigment.

First antennce. Pirst joint stout, about once and a half as long as broad, second much

shorter and thinner, third about half the length of second ; flagellum in male of forty-

one joints, the first longer than the last of the peduncle, followed by many joints not

longer than In'oad, to which succeed several much longer than broad.

Second antennce. The basal joints short, the last joint of the peduncle rather long,

longer and thinner than the penultimate, which has an apical tooth ; the flagellum in

the male similar in structure to that of the first antenna, but perhaps shorter ; thirty-

three joints in an example not quite perfect.

Upper lip wath broad front, the margin little curved.

THE COPEXHAGEN MUSEUM AND OTHEE SOURCES. 43

Ilatidibles. The cutting-edge small, little dentate, the molar massive; the third joint of

the jmlp hroad, distally fringed with spinules.

First ma.rillcB. Inner plate oval, tipped with two setse, outer plate with the eleven

apical spines very small, inconspicuously denticulate ; second joint of the palp broad,

with some apical setules.

Second maxill<B. The inner j)late hroader than tlie outer, both apically fringed with

spines, which are longer on the outer plate.

Ila.rilUpeds. The inner plates broad and with the inner margins pi'otruding ; the outer

plates reaching scarcely beyond the end of the first joint of the palp, fringed wdth slender

spines on the inner margin ; the second joint of the palp rather large, fringed with long

setjB, the third joint much narrower but not much shorter, the fourth both short and

narrow^, tipj^ed wdth spines or setfe.

First gnatJiopods. Side-plate distally widened. The second joint is moderately long

and narrow', unarmed ; the fourtli little longer than the third ; the fifth in the male

considerably longer and narrower than the sixth, both having the hind margin fringed

Avith spinules; the sixth is rather longer than broad, with S2:)inules at the front apex, and

a small palm which matches the weak finger. In the female there is little difference in

the length and breadth of tlie fifth and sixth joints.

Second gnatJiopods. Side-plates broader and of more uniform width than the preceding

pair. In the male the second joint is narrowed at the point of attachment and broadest

near the centre, though nowhere very broad ; the fourth joint is longer than the third,

but shorter than the fifth, all three being narrow ; on the contrary, the sixth, besides

being longer than the fiftli, is from the very base enormously broader, its front margin

nearly straight, the ojiposite curved, slightly crenulate, the broad, slightly sloping palm

divided into three or four irregular teeth ; the smooth, curved, and rather massive finger

closes down over the palm into a great pocket excavated in the thickness of the hand.

In the female these limbs closely resemble the feeble first gnathoi:)ods, but with the fifth

and sixth joints a little longer.

First per (Bopods. Side-plates with convex front and concave hind margin. The second

joint moderately long, the sixth longer than the fourth or fifth, which are subequal ; the

finger sliort, acute, slightly curved, having a spinule on tlie concave margin.

Second perceopods. Side-plates larger than the preceding, the hind margin excavate,

serrate below the excavation. The limb resembles that in the preceding pair, but with

the fourth and fifth joints a little longer.

Third perceopods. Side-plates not very large, pretty equally bilobed, the hind lobe

produced below the front. The second joint tending to oval, the hind margin feebly

serrate ; the fourth joint rather strongly produced downward.

Fourth perceopods. Side-plates with hind lobe produced much below the front. The

second joint more oblong tlian in the preceding pair, the hind margin nearly straight,

fringed with long setge ; the fourth joint strongly produced.

Fifth piei'ceopods. Side-plates small. Second joint larger than in the preceding pair,

the straight hind margin more strongly produced downward ; the fourth joint similar

to that in the preceding pair, but with more numerous spines ; the fifth and sixth joints

44 EEV. T. K. E. STEBBING ON AMPHIPODA FROM

are narrow, elongate, subequal, with numerous margiual spines and spinules ; tlie finger

comparatively small.

Pleojwds. Inner margins of the peduncles closely adjacent ; coupling-spines small ; rami

with eleven or twelve joints, and two cleft spines on the first joint of the inner ramus.

Uropods. Of these little more can be said than is stated in the account of the genus.

The short peduncle of the third pair has a dentate. apex, to which the long inner ramus

is perhaps very loosely attached, as it was wanting from the majority of specimens,

notwithstanding the protection given by the folding of the j)leon ; in young ones not

yet released from the maternal pouch it was well developed.

Telsoii not longer than broad, scarcely so long as the peduncle of the third uropods,

the sides convex till near the apex.

Length, without the flexed portion of the pleon, from about a tenth to an eighth of

an inch, or 3 mm.

Localitij. Port Jackson, in Australia. Sent by Professor W. A. Haswell, M.A., D.Sc.

The specific name is derived from ^Aartrc, broad, and rwroc, a back.

EXPLANATION OF THE PLATES.

U.S., upper antenna ; a.i., lower antenna.

I.S., upper lip; lA., lower lip.

m., mandible; mx. ], 2, 1st and 2ud maxilla; nixp., luaxillipcds.

(jn. 1, 2, 1st and 2nd gnathopods ; prp. 1-5, 1st to 5th pcrteopods; br., branchial vesicle.

pip., plcopods ; ur. 1, 2, 3, 1st, 2nd, and 3rd uropods.

T., telson.

A line above the figure of a whole specimen indicates the natural size.

Plate 6.

Parhijale fasciger, n. g. et sp.

The lateral view of the whole animal and the figures on the left hand and down the centre of the Plate

are from male specimens, those on the right hand are from a female specimen.

The antenniB and appendages of the perteon and pleou have a uniform enlargement ; so also, but

on a higher scale, the mouth-organs, portions of the gnathopods of both sexes, the third uropods

and telson of the male, second and third uropods and telson of the female, portions of the first

maxilla and mandibles being still more highly magnified.

Plate 7.

A. Lysianax cinghaknsis, n. sp.

All the parts are magnified to the same scale, except a portion of mx. 1, which is more highly magnified

than the rest.

B. Lysianax cubensis, n. sp.

The antennae, limbs, uropods, and telson are drawn to the same scale, while still more magnified figures

are given of the mouth-organs, part of the second gnathopod, second and third uropods, and telson

in two positions.

THE COPENHAGEN MUSEUM AND OTHEIi SOURCES. 45

Plate 8.

Andmiiotes corpulentus (Thomson).

Antennte, moutli-organs, uropods, and telson, more magnified than the limbs and figures of uropods and

telson at foot of Plate. Mandibles seen from the outside, so that the accessory plate is not visible.

Plate 9.

Kr Sancho phityvotus, n. g. et sp.

Dorsal view of a male specimen, the last three joints missing in the third, fourth, and fifth perteopods.

The mouth-organs, uropods, and telson (in both sexes) are magnified more highly than tlie other parts.

B. Pontharpinia pinguis (lias well).

The mouth-organs and telson are more highly magnified than the other parts.

Plate 10.

Li'iiculhoe incha Robertson.

Antennfie, appendages of peraeon and pleou, on a uniform scale, other parts more enlarged. Pl.x. 1, 2, 3,

postero-lateral angles of 1st, 2nd, and .3rd pleon-segments. pip.sp., coupling-spines fj-om [leduncle

of pleopod.

Plate 11.

Anainixis Hanst'iii n. g. ct sp.

In the lateral view of the animal the ends of the 3rd, 4th, and 5th perieopods are missing.

a.s.Pi.., a.i.A.., the antennte of a second specimen.

or.l., supposed oral lamina projecting vertically from underside of head.

m.rp. (in middle line of Plate), maxillipeds as seen from within ; mrp. A., from a different specimen,

the lower figure giving a lateral view, the upper an exterior one.

ffn. 1, (/n. 2, the figures on the left hand are fi'om the inner side of the limbs, those on the right

from the outer side. In the latter the finger and part of the hand of y/(. 2 are missing.

Plate 12.

Pardaliscoides ietiellus Stebbing.

The mouth-organs are more highly magnified than the other parts.

Plates 13, 14.

Eusiropsls Riise'i, n. g. et sp.

In Plate 13 the first gnatbopod is seen from tlie outer side, in Plate 14 from the inner side.

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VI. Part I. 1894 2 0 0 .

Part II. 1894 1 11 0 .

Part III. 1894 0 10 0 .

Part IV. 1896 1 4 0 .

Part V. 1896 0 10 0 .

Part VI. 1896 0 8 0 .

Part VII. 1896. ... 0 12 0 ,

Part VIII. 1897 0 2 6 .

VII. Part I. 1896 0 10 0 .

Part II. 1897 0 12 0 .

Price to

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d.

ued).

2nd Ser. ZOOLOGY.]

[VOL. VII. PART 3.

THE

^^/Z

TRANSACTIONS

OP

THE LINNEAN SOCIETY OF LONDON.

THE ORIGIN OF THE CORPUS CALLOSUM:

A CO:\IPARATIVE STUDY OF THE HIPPOCAMPAL REGION OF THE CEREBRUM

OF MARSUPIALIA AND CERTAIN CHEIROPTERA.

BY

G. ELLIOT SMITH, M.D., Ch.M. (SycNEY),

' JAMES KING " RESEARCH SCHOLAR OF THE UNIVERSITY OF SYDNEY ; ST. JOHn's COLLEGE, CAMBRIDGE.

{Communicated hij Prof. G. B. Howes, Sec. Linn. Sue.)

LONDON:

PRINTED FOR THE LINNEAN SOCIETY

BY TAYLOR AMD FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BITRLINGTON-HOUSB, PICCADILLY, W.

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

Jinir 1897.

r 4.7 ]

III. T/ie Oricfin of the Corpus Callostim : <!■ Comparative Study of the Jllpyocampal

Mec/ion of the Cerebrum of Marsupialia and certain Cheiroptera. Bij G. Elliot

Smith, M.D., Ch.M. [Sydney), " James King " Besearch Scholar of the University

of Sydney ; St. John's College, Cambridge. (Communicated by Prof. (i. B. Howes,

Sec. Linn. Soc.)

(Plates 15 & 16.)

Eciul ilst January, 1S97.

IT is now a generally recognized fact that the dorsal commissure of the Metatherian is

not strictly homologous to the similarly-situated commissure of the Eutherian cerebral

hemispheres. For while the dorsal commissure of the Marsupial springs mainly, if not

wholly, from that peculiar cortical formation which we know as " hippocampus," its

topographical representative in the more highly-organized mammal is derived from a

much wider cortical area, of which the hippocampus constitutes a part — and in the great

majority of cases only a relatively very small j^art. In other Avords, the dorsal commis-

sure of the Metatherian is essentially " hippocampal," while that of the Eutherian

cerebrum is partly " hippocampal " and partly " non-hippocampal." These " non-

hippocampal " fibres of the dorsal commissure of Eutheria are derived from the general

or typical cortex which Sir William Turner calls ''pallium.'"

It will be found that in higher mammals, such as the Primates, the Cetacea, the

Carnivora and Ungulata, the " pallial " element forms the main bulk of the dorsal

commissure. But if we compare a large series of mammalian ccrebra we find that,

speaking generally, there is a rapid decrease in the extent and importance of this

" pallial " factor as we descend the Eutherian scale. The " pallial " or " non-hippo-

campal " factor shows a rapid actual decrease, while the hippocampal factor takes a

continually increasing share in the constitution of the dorsal commissure. Erom

such considerations, and from the knowledge that the " pallial " factor was wanting

altogether in the Marsupialia, it seemed likely that some Eutherian form might be

found in which the newer " non-hippocampal " element might be so slightly develoiDcd

as not to interfere with or destroy the resemblance of its dorsal commissure to that of

the Marsupial. And if such a transitional form could be found we ought to be able to

decide the exact relation of the newly-developed " pallial " fibres to the pre-existing

" hippocampal " fibres, and hence form some accurate conception of the nature of this

new commissure, which in its highly-developed state in man we know as the " coipus

callosum."

The desired " connecting links " I have had the good fortune to find in certain

Cheiroptera — Nyctophilus Timoriensis and Miniopderus Schreibersii — both of which, but

more especially the former, realize the conditions above stated.

In this contribution I propose to compare the commissures and certain ncighbom'ing

SECOND SERIES. — ZOOLOGY, VOL. VII. 8

48 DR. G. ELLIOT SMITH ON THE

cortical areas of these bats with the Marsiijiial type, in order to find out the distinctive

mode of arrangement of the former. Having determined the nature of the dorsal

commissure of the bat and its relation to the pre-existing type, I shall attempt,

by means of comparison with more highly-developed Eutherian forms, to indicate the

true lines along which the evolution of the corpus callosum proceeds in the Mammalia.

For a considerable time I have been aware of the fact that Zuckerkandl, in his

remarkable work upon the olfactory centre (' Ueber das Eiechcentritm,' 1887), had

grOviped together the brains of Monotremes, Marsupials, and certain small Cheiroptera

on the ground that they presented in common certain features in whicli they differed

from all other mammals.

These distinctive features were stated in the following terms : — (1) that theRandbogen

[or Randwindung — Gyrus marginalis *] retains its embryonic form, i. e. that it is in all

parts equally broad, and extends up to the Ammonsfurche *, and is continuous with the

mesial wall of the hemisphere anteriorly ; (2) that the corpus callosum is rudimentary ;

and (3) that the Balkenwindung* is wanting.

From the fact that Zuckerkandl uses the term Randbogen instead of hippocampus we

might infer that he did not definitely recognize the dorsal part of the Randbogen as

hipjiocampus — an inference which is borne out by his reference to the corpus callosuni.

If any other evidence were needed to show that Zuckerkandl quite failed to appreciate

the most salient features of the Monotreme and Marsupial cerebrum, it is provided in

his remarks upon the cerebrum of Echidna, where he speaks of the fascia dentata as

"der ventrale Schenkel des Randbogens." This clearly indicates that he did not

recognize the dorsal limb of the Randbogen as fascia dentata or hippocampus. [It is

only right to mention that Zuckerkandl's work appears to have been purely macroscopic]

Thus Zuckerkandl reduces the cerebrum of the Marsupial and Monotreme to the

conventional Eutherian type, possessing a true corpus callosum, and with a hippocampus

practically limited to the descending limb of the lateral ventricle. Such l)eing the case,

until quite recently I paid little heed to his remarks concerning the resemblance of

Vespertilio murinus (the bat of which he examined the brain) to the Marsupial type ; for,

having reduced the Marsupial to conformity with a simple Eutherian type, it seemed very

natural to group an actual example of such a type (wliich the bat provides) with the;

Marsupial.

But quite recently, vipon examining the brain of a common Australian bat {Nycto-

•philus Timoriensis), I was struck by the remarkable resemblance which its hippocampus

(Zuckerkandl's Randbogen) and cerebral commissures present to the Metatherian

type. It appeared to be a case of reducing the bat to the Metatherian condition

rather than advancing it to the Eutherian status, as Zuckerkandl's researches would

appear to indicate. In the course of this communication we shall see how far this

appearance is justified by the histological examination of NyctopMlus and liinioplenis.

The object of this paper being to consider phylogenetically the origin of the true

corpus callosum (as distinct from the hippocampal commissure), we are solely concerned

with the transition from the condition found in the Proto- and Metatheria, in whicli

* These terms will le explained subsequently.

OKIGIN or THE CORPUS CALLOSUM. 49

the true corpus callosum is wanting, to the Eutheria, in which alone that structare is

found. This relieves us from the necessity of discussing the writings of Oshorn and many

others who have hased their researches primarily ujion the examination of some sub-

mammalian form, and from this treacherous standj)oint have advanced liypotheses to

include the Mammalia.

Since Flower (' Pliilosophical Transactions,' 1865) compared the cerebral commissures

of the jMarsupial with those of certain lowly-organized Eutheria, in ordej' to determme

the nature of the former, no one, so far as I know, has dealt Avith the subject from this

comparative standpoint. But while Elower compared the two series in order to throw

light upon the Marsupial, I am instituting the reverse process of comparing the

Cheiroptera with the more distinctly defined Metatherian tyj)e.

Within the last three three years the labours of Blumenau *, Marchand f , and Paul

Martin + have added considerably to our knowledge of the process of development of the

corpus callosum in the higher mammals. And it is very instructive to compare the

2n"0gress of the developing commissvu-e in man or the cat with the stages of its jjhylogeny

with which this contribution deals.

The following statements concerning the ontogenetic process are a free translation of

certain of Martin's conclusions {he. cit.) : — A thickening takes place in the lamina

lerminalis, which later disappears ; but before the disappearance the first fibres of the

corpus callosum apjiear in the dorsal j^art of the thickening. [Martin throughout uses

the term corpus callosum (Balken) in the sense of the whole dorsal commissure,

includhig the hippoemn'pal eomrnissnre. This will be apparent from the next statement.]

The first " callosal " fibres spring from the posterior columns of the fornix. The ventral

part of the corpus callosum [the psalterium] consists of fibres which run in the inner

Randbogen. The splcniimi is composed of fibres which extend from the inner and

outer Eandl)ogen to the other side. Tlie Ijody and genu of the corpus callosum consist

of fibres passing through the outer llandbogen. The cavuni septi pellucidi is formed

during the disajipearance of the thickened lamina terminalis, jmrtly in the place of the

disappearing thickening, but mainly by the inclusion of a part of the longitudinal

fissure of the cerebrum by the corpus callosum. For a long time it is open naso-

vcntralh^ Upon the ventral side of the corpus callosum a gradual " soldering " of the

hemisphere-walls takes place in the situation of the cavuni septi. The corpus callosum

increases by intussusception as well as by apposition of fibres. The striae lougitudinales

are formed in part by the upper llandbogen. The thickened lamina terminalis contributes

towards the formation of the caudal j)art of the striae mediales.

In the subseqvient consideration of the results of our comparison we will see the

extent to which the ontogenetic process recapitulates the phylogenetic history. At the

* '• Zur Eutwickelungsgeschichte iind feineren Anatomie des Hiriibalkens," Arcliiv fiir mikroskopisehe Anatomie

JBd. xxxvii. 1891, pp. 1-14, Taf. i.

t " TJeher die Entwic-keluDg des Balkeus im menschlichen Gehirn," Arohiv fiir mikroskopische Anatomie

Bd. xxxvii. 1891, pp. 298-334, Taf. xv., xvi.

X " Bogenfurche und Balkenentwickelimg bei der Katze," Jenaische Zeitschrift fiir Xaturwisieiisohaft, Bd. xxis.

1895, pp. 221-252, Taf. ii. and 13 figiu'cs in text.

8*

50 DR. G. ELLIOT SMITH ON THE

same time we will see how tlie latter explains mucli that is apparently meaningless and

purposeless in the ontogenetic process.

From the foregoing remarks concerning the scope of this investigation, it must he

evident that we are mainly concerned with the hippocampal region of the two types of

cerehrum. In other AA^ords, we are going to study and compare the dorsal commissure

of the Marsupial, which is " hippocampal," with its topographical representative

in the bat, which is mainly " hippocampal." It is therefore necessary to have a

clear and definite idea of disposition of the hippocampal region of the Metatheriau

cerehrum ; and we may first of all consider the hippocampus of Pcrmncles nasiita, which

exhibits very clearly the distmctive features of the Marsupial brain (mainly by means

of sections stained by the Weigert method).

I have not yet been fortunate enough to get specimens of the brain of Nyctophilus in

a condition suitable for the application of the Weigert stain. But the resemblance

to the Marsupial type is so great that with the aid of the lithiiun carmine stain

quite sufficient detail can be made out to reveal the distinctive features of the region

with which we are concerned. I hope soon to be able to supplement these notes by a fuller

paper on the brain of Nyctophilus, studied by more specialized neui'ological methods*.

My friends Mr. James P. Hill and Mr. J. Macpherson, of the University of Sydney,

very kindly placed at my disposal four brains of NijctopMlus which were in a good state

of preservation, though hardened only in alcohol. My friend Dr. R. Broom, who was

at Taralga working at the organ of Jacobson in Iliniopterus, kindly gave me the brain

from one of his specimens. Mr. Robert Grant, the able assistant in the Physiological

Laboratory at Sydney, stained and cut series of coronal, sagittal, and oblique sections

from these specimens. To these gentlemen I acknowledge my deep gratitude and great

indebtedness.

This Avork was done mainly in the Anatomical Department of the University of

Sydney, and has been completed — so far as such an unfinished work can be said to be

— in Cambridge.

The Hiirpocampal JRegion in the Marsupial.

The mesial wall of the descending limb of the lateral A'entricle of the cerebrum of the

Marsupial presents a marked prominence, which extends in the long axis of the ventricle.

This is the hippocanqyus — the homologue of the hippocampus major of the Primate brain.

In its histological structure and in the disposition of its constituent parts this region of

the Metatherian cerebral hemisphere agrees exactly with the corresponding part of the

Eutherian, so that in seeking for distinctive features of the two types of brain it

may be neglected. We will therefore begin the study of the brains under consideration

at a point just in front of the place where the lateral ventricle begins to curve doAvuAvard

to form its descending cornu.

The first figure (PI. 15. fig. 1) represents a coronal section through the forebraiu of

* Since this Tvas -n'ritteii I have coiifinned, by menus of i>re]iaratioiis stained by Weigert's method, all the

observations concerning JS'i/ctojihiltis which are here recorded.

ORIGIN OF THE COEPUS CALLOSUM. 51

Perameles nasiita at about the junction of body and descending limb of the lateral

ventricle. This corresponds to a situation almost immediately behind the commissures of

the liemispheres, as we shall see later.

In this section the 'tween-brain — a somewhat square-shaped mass with rounded corners

— will be seen to occuj)y the ventral mid-region. The basal part of the thalamic region

lies upon the optic tract {o.tr.), which may be seen extending into the furrow between

the hemisphere (tlie region of the nucleus amycjdahv, n.a.) and the 'tween-brain. The

two halves of the ojitic thalamus are connected by means of a broad bridge of grey

matter — the commissura moUis (cm.) — and above and below the latter portions of the

third venti'icle may be observed. The small recess of the third ventricle lying above

the soft commissure is roofed by a somewhat dome-shaped epithelial fold, which is

attached on either side to a ridge containing a longitudinal band of meduUated fibres —

the sti'ia medullarls thalami (s.m.t.).

Upon its lateral aspect the thalamic region fuses with the corpus striatum of the

cerebral hemisphere, and a mass of medulltited fibres, cut either transversely or ol)Iiquely,

indicates the place of union. The corpus striatum consists of two parts, which are

separated one from another by the internal capsule (ci.). A smaller grey mass, lying

above the internal capsule and projecting into the lateral ventricle, is the iiucleus

caudatus (n.c). A larger grey mass lying below the internal capsule is the nucleus

lentlcularis {u.L). The ventral part of the nucleus lenticularis [n.a.) is the homologue

of the grey mass known in human anatomy as the nucleus mnygdalce. It is directly

continuous with a cortical area of distinctive structure known as \hQ liyr'iform lobe [i^y.l.),

from which the nucleus lenticularis in its upper part is separated by a layer of meduUated

fibres (the external capsule, c.e.).

Along its dorsal border the pyriform lobe is separated from the general cortex (which

Turner calls "pallium," p.) by the shallow rhinal fissure {f.r.). Above the corpus

striatum, where the lateral wall and roof of the ventricle are formed by this general

cortex ov pallium, the inner lining of the latter is formed by a mass of meduUated fibres

— the corona radlata {c.r.) of writers. If the cortex be traced in a mesial direction its

edge wUl be found to present those peculiarly distinctive features which w^e at once

recognize as hippocampus. Thus if the mesial waU of tlie hemisphere be traced down-

ward in the section (fig. 1, PL 15) we reach a deep indentation — the hippocamptal fissure ,

and corresponding to this fissure a marked prominence into the lateral ventricle forming

the hippocampus {hip.). Below the hippocampal fissure the characteristic features of

the fascia dentata (fd.) (Avhich we shall consider subsequently) are immediately

recognizable. And extending into the deep depression between the nucleus caudatus

{n.c.) and optic thalamus is the prominent _^mir/ff (fi-), spur-like in transverse section.

[In order to avoid an luinecessary confusion in the figure, the choroidal fold of the

lateral ventricle which is attached to the fiml)ria has not been represented.]

Having thus seen how the " hippocampal formation " constitutes the edge of the

cortex cerebri, I propose to carefully examine the series of changes whicli this peculiar

formation undergoes as we trace it forward in a series of coronal sections of the cerebrimi

of the bandicoot (Perameles).

52 DK. G. ELLIOT SMITH ON THE

A coronal section tlirongh the cerebrum, just in front of that represented in the first

figure, presents a marked change in the appearance of the hippocampal region, Avhich

is represented upon an enlarged scale in fig. 2. The hijipocarapus itself, as well

as the fascia dentata, have undergone practically no change, but a huge bundle of

medullated fibres from the upper part of the fimbria is now exposed in the act of crossing

the middle line. This is the posterior exti'emity of what — to avoid confusion of terms —

will for the present be termed the commissura dorsalis (c.i).).

It would be foi-eign to the scope of this work to descril)e in detail the histology of the

hippocampal formation, seeing that the minute structure of the Metatherian hippocampus

is identical with that of the Eutherian, which Sala, Schaff'er, Ramon y Cajal, and

von KoUiker*, among many others, have so carefully and minutely described Avithin

recent years. But I wish to call attention to certain features which are intimately

associated with the evolution of the structure we are primarily considering.

Lying upon the upper surface of the " dorsal commissure " (c.d.) there is a complicated

epithelial fold the outline of which is roughly triangular, and which projects upward into

the great cleft between the two cerebral hemispheres. The fascia dentata {f.d.) lies in

contact with this epithelial (choroidal) fold on either side, and may be easily recognized

by certain distinctive features. Thus it possesses a very thickly -packed column of small

cells — the stratum gramdosum (s.fjr.) — the nuclei of which stain very deeply, lying parallel

to the surface, from which they are separated by a clear layer almost devoid of cells — the

stratum molecuJare. The fascia dentata — consisting of stratum granulosum and stratum

moleculare — is folded in a peculiarly characteristic manner. Its mesial extremity is

completely bent upon itself, so that the stratum moleculare or superficial layer rests

upon the dorsal aspect of the dorsal commissure. The lateral extremity of the fascia

dentata undergoes a corresponding bending, the concavity of which is directed toward the

mesial plane. It would appear that the fascia dentata had continued to increase in

breadth whilst its mesial and lateral extremities were relatively fixed, and, to accommodate

itself to tliese conditions, it bad bulged out into a pouch, as it were, and at the same time

become flattened by the resistance of the general cortex lying immediately above it. Such

factors, in reality, seem to have been at work, as I have recently pointed out t. The

fissure which separates the fascia dentata from the general cortex where their resj^ective

superficial layers come into contact is ihefissura hipiMcampi (f.h.).

The concavity of this pouch of fascia dentata is occupied l)y scattered nerve-cells, many

of which give origin to the brush of medullated fibres which are to be seen in the figure,

collecting near the inner margin of the fascia dentata, to lose themselves in the huge

mass of medullated fibres lying immediately below.

The hippocampus proper projects as a large rounded swelling into the lateral ventricle.

This swelling is covered by a thick layer of medullated fibres — the so-called ulceus (alv.).

These fibres almost all pursue an obliqiie course, so that in a coronal section only short

pieces of ^fibre are seen massed together. In the first figure most of the fibres of the

* ' Gewebelehre des "Munsohen,' Bd. ii. zwciter Hiilt'te, IS'JG.

t '■ The Fascia Dentata,"' Auatomischer Aiizeiger, xii. Bd. Nr. 4 iind .5, 1895, p. 119.

OEIGIN OF THE COEPUS CALLOSUM. 53

alveus are tending towards the fimbria, but in the section under consideration many

fibres of the alveus, as well as fibres coming from the " pouch " of the fascia dentata,

proceed directly into the commissura dorsaUs along with many fibres of the fimbria

which have come from more caudally situated regions of the hippocampus. It will be

noticed, however, in the figure that as yet only the upper part of tlie fimbria is

contributing fibres to the commissure. The tip of the fimbria, which contains fibres

coming from the most distant parts (temporal pole) of the hippocampus, is yet undisturbed

and has given no contriluition to the dorsal commissure. Between the alveus and the

curved lateral part of the hippocanipal fissure there is a broad, more or less definitely

stratified region. Slightly nearer to the alveus there is a very uniform and clear layer

(in specimens stained by Weigert's method). This is the layer of " ^lyramidal cells," and

consists of a closely-packed column of large cells, which stain moderately with ordinary

stains. Between the layer of pyramids {i^yr.) and the alveus {ctlo.) there is a stratum

containing scattered polymorphous cells and very abmidant medullated nerve-fibres — the

layer of poli/morphous cells. The space between the hippocamjjal fissure and the layer of

pyramids is usually divided by writers into three zones — a broad clear layer next to the

layer of pyramids [stratum radiatum, s.r.), a thin superficial layer [stratum zonale), and

an intermediate layer very rich in medullated nerve-fibres [stratu^ii lacunosum, s.l.).

A large number of fine medullated fibres (.r) extend from the region of the layer

of pyramids through the stratum radiatum into the stratum lacunosum. These fibres

are very distinct in the region bordering upon the fascia dentata [clde fig.). In the

stratum lacvmosum many of these fibres end by means of free branching in relation to

the processes of the pyramidal cells, which extend through the stratum radiatum into

the more superficial regions. But a considerable number of medullated fibres assume a

longitudinal direction (/. e. in the long axis of the hippocampus) as soon as they reach

the stratum lacunosum [s.l.). These fibres, which may 1)e called " longitudinal association

fibres of the hipjwcamj^us," appear in transverse section [s.l.) as rounded bundles

immediately surrounding the lateral or deeper part of the hippocampal fissure.

In the general cortex [j).) the cells are scattered throughout the whole thickness of the

cortex, whereas in the hippocampus (leaving out of account the fascia dentata) the great

majority of the nerve-cells are crowded together into the regular row of pyramids. The

transition-region from typical cortex to typical hippocampus is generally known as the

sub/culuv/, cornu animonis [sub.). AVhether the " subiculum" ought to be grouped with

the general cortex or with the hippocampus is a question to which Ave shall have to refer

su.bsequently. The deej)est layer of the general cortex consists of a mass of medullated

fibres — the corona, radiata. It will be noticed at a glance that while the fibres derived

from the hippocampus and " subiculum " proceed into the alveus, those derived from the

general cortex proceed away from the alveus, i. e. towards tlie external capsule. At the

point of meeting of alveus and corona radiata there is obviously a commingling of fibres,

but it is equally clear that any passage of fibres from the alveus into the " corona ''

or vice versci is either non-existent or extremely slight and practically negligible. In

the adjoining regions there are groups of longitudinal fibres belonging respectively to the

two distinct formations, and it is quite possible that an interchange between these two

54 DE. G. ELLIOT SMITH ON THE

series may take place. The longitudinal series belonging to the margin of the general

cortex or pallium is the so-called cingulum of higher forms (figs. 6 & 11, cing., clngJ).

There are, however, definite bonds of union between hippocampus and general cortex

which are found in their junction. Thus from the stratum zonale and stratum lacunosum

of the hippocampus fibres extend not only into the " neutral ground," so to speak, of

the " subiculum cornu ammonis " but well into the molecular layer of undoubtedly true

cortex. This is a definite association bundle between hippocampus and pallium, which

may be called tractus hippocamfi ad pallium, (fig. 2,?/).

As the hippocampal region is successively examined in a series of coronal sections, the

main features of the hipj)0campal formation itself remain imchauged for some time, but

its commissure — the commissura dorsalis — undergoes marked changes.

Thus the depth of the commissure rapidly increases at the same time that the

prominence of the fimbriae is diminishing (fig. 3). The meaning of this is that an

increased number of fibres from the fimbria are crossing in the dorsal commissure. The

scheme (fig. 1) of the commissures as they are seen ia sagittal section explains the

meaning of these changes.

In figure 5 a new factor for the first time becomes evident. Upon the lateral aspects

of the commissure, more especially upon the right side of the figure, a mass of grey

matter {s) will be observed to enclose the dorsal commis.sure and to become continuous

ventrally with a mass enclosing a second commissu.re — the commissura ventralis. This

grey mass enclosing the two commissures will for the jiresent be distinguished as the

" commissure-bed." On either side it will be noticed to become continuous by a narrow

bridge of grey matter with the corjms striatum (est.). In this narrow bridge there are

a number of longitudinally-coursing nerve-fibres (s.t.). These are the uncrossed fibres

of the stria ter'minalis, the other fibres of which may l)e seen entering the ventral

commissure {s.t!.) in figure 3 to cross to the other side. In figure 5 the dorsal

commissure has reached its greatest depth.

Figure 6 shows the appearance which is presented by a section after all the

commissural fibres of the fimbria have crossed. The thin commissura dorsalis (c.d.) is

derived from the corresponding region of the hippocampal formation. The huge

commissura ventralis (c.v.) appears to become continuous with the capsula externa [ce.],

which, after being joined by fibres of the capsula interna (cL), becomes the corona

radiata. The dorsal and ventral commissures lie in the large mass of grey matter which

forms the commissure-bed. A thin lamina (?') of this grey mass may sometimes be

distinguished upon the dorsal as^jcct of the commissura dorsalis. This may be

distinguished as the " indusium vertim."

The " commissure-bed " (s) contains large numbers of uncrossed fibres (d.f.), which are

derived from the alveus of the hippocampus (which is situated above them) and from

the fimbria. These fibres are divided into two groups by the ventral commissure. The

p)ostcommissural fibres (columna fornicis, c.f.) collect upon the dorsal aspect of the

ventral commissure and incline backward and downward to enter the thalamic region.

The precommissural fibres proceed downward and forward in front of the ventral

commissui'e.

OEIGIN OF THE COEPUS CALLOSUM. 55

As we proceed forward in tlie examination of coronal sections, the dorsal commissure

will be found to become gradually thinner and finally disappear altogether, while the

desceudmg foniix-fibres remain unchanged. The ventral commissure disappears in

about the same coronal plane. The " commissw^e-hed " extends a slight distance further

forward before the hemisplieres become separated one from another.

Pigure 7 represents (about four times the natural size) the appearance of a coronal

section immediately in front of the place where the hemispheres become separated from

each other.

In this figure the hippocampus is again easily recognizable, although its conformation

has become greatly simplified. The fissura Idppocampl (f.h.) is much shallower, and the

hipj)Ocampal projection into the ventricle less prominent. The fascia dentata is much

narrower, and consequently much less folded. The thin alveus may be seen proceeding

directly into the mass of desceudinfj forwix-fihres which occupy the superficial portions

of the grey mass which we may call the " corpus prcecominissiiralc" *, but which is really

only the anterior continuation and homologue of the grey mass which further back has

been called " commisstire-bed.'" The other features of the section do not concern us in

considering the hij)pocampal formation. The only other point to which I wish to call

attention is tliat the " corpus prcecommissurale " is directly continuous below the lateral

ventricle with the corpus striatum, where the latter is capped by the peculiar cortex

which Ganser calls the " cortex of the head of the corpus striatum," and which

corresponds to the " tubei'culnm olfactorimi " [t.o.) — such a prominent feature upon the

ventral aspect of this brain.

If we were to trace these various structures forward in a series of coronal sections,

we should find that the hippocampal fissure would become gradually shallower until it

eventually disappeared, the prominence in the ventricle disappearing pari passu. The

fascia dentata, now placed entirely upon the surface, becomes narrower and less clearly

differentiated, until at last we fail to recognize any distinguishing feature of a hippo-

campus. But by the time this has occurred we have arrived almost at the olfactory

pedvtncle. In certain Marsupial brains {Dasyuriis clverrinus) it is even possible to

distinguish the hippocampal formation as far forward as the olfactory peduncle, so that

here wo have the "precommissural area " completely cut off from the general cortex or

pallium {p.) by a hippocampal band, as semi-schematically represented in figure 8

{hip." & f.d.). This is the primitive condition of the hippocampus, which is found

(although recognized with difficulty) in the Reptile, and which I have already described

in the fcetal OrnithorMjnclms (Qu. Join-. Micr. Sci. vol. xxxix. pp. 181-206).

Pigure 9 represents the appearance which this region presents in Perameles when

viewed from its mesial aspect.

In this figure the optic nerve (opt) is seen extending towards the lamina terminaHs, at

the inferior extremity of which is the oval section of the optic tract (o.tr.). Extending

upward from the optic tract is the thin ventral portion of the lamina terminalis' —

the lamina cinerea {I.e.). At its upper part this lamina expands to enclose the large

* By " corpus pnicommissunde " is meant that grey mass the mesial surface of which is the "precommissural

area " (p.a.).

SECOND SERIES.— ZOOLOGY, VOL. VII. 9

56 DK. G. ELLIOT SMITH ON THE

commissura veiitralis (c.v.), oval in section and placed obliquely. Extending upward

from the ventral commissure there is a thick mass of grey matter — the "com-

missure-bed'" {s) — Avhich contains in its upper part the commissura dorsalis (c.D.),

shaped somewhat like an inverted obliquely placed V Avith the dorsal limb nearly

horizontal.

Above the dorsal commissure the fascia dentata {f.d.) is easily recognizable and is

separated from the general cortex (jk) by the fissura Mppocamjpi {f.h.). Anteriorly the

hippocampal fissure gradually becomes shallower until it can no longer be traced, so that

the fascia dentata, the stratvim zonale of the hippocampus, which now of course lies upon

the surface (compare figure 8, hip.'"), and general cortex {p.) are indistinguishable. Upon

its ventral side the fascia dentata becomes directly continuous with the extensive pale

region which constitutes the " frecommissnral area" (p.a.). In the forward direction

the "• precommissural area " is directly continuous with the mesial wall of the extremely

short olfactory peduncle, which connects the hemisphere with the olfactory bulb {o.h.).

Upon its ventral side the " precommissural area " becomes continuous with the grey

boss generally known as the " tuherctihtm oJfactorinm " {t.o.).

By means of this representation of the anterior portion of the mesial wall of the

hemisphere of Ferameles (fig. 9), and the semi-schematic representation of the corre-

sponding region in Dasyurus (fig. 8), we obtain a good general idea of the anatomy of the

commissural region.

In Dasyurtis it will be observed that the dorsal commissure is not so distinctly

bilaminar as it is in Pe/'flrtK'/fs : and in Phascolarctos (PI. 16. fig. lOj it can hardly be

called bilaminar. Thus we have in the Marsupial all the intermediate stages between

the rounded dorsal commissure of Oriiithorhynchiis and Echidna and the distinctly

bilaminar form found in most mammals. There are certain important features of

this region which can only be demonstrated by sagittal section, which we will

consider almost immediately. But before leaving the consideration of figure 8,

I wish to call attention to the possible consequences of elongation of the commissura

dorsalis.

The " commissura dorsalis " is contained in the mass of grey matter which I have

called the " commissure-bed," the separate anterior prolongations of which in the

two hemispheres are formed by the '^corpora j^'^ffcommissuralia'" — the grey masses

corresponding to the surface-region of each hemisphere, which is distinguished as

"precommissural area." Now this combined grey mass — " commissure- bed" and

" corpus prnecommissurale "■ — is separated from the general cortex (pallium) above it by

tlie hippocampus ; and the dorsal limb of the commissure separates the " commissure-

bed " from what we may call the " supracommissural hippocampus," while the " corpixs

prsecommissui'ale " becomes directly continuous with wdiat we may call tlie " pre-

commissural hippocampus." Now it is clear that if the dorsal commissure elongates in

the forward direction it must cut otf jiart of this " precommissural " body from the

precommissural hippocampus, which becomes " supracommissural." The structure

lying upon the ventral aspect of such an elongated dorsal limb of the commissura

dorsalis must be either " commissure-bed " or " corpus pra^commissiu'ale."

ORIGIX OF THE CORPUS CALLOSUM. 57

Figure 10 represents the appearance of a sagittal section through the corresponding

region in the brain of Phascolarctos clnereus, after stciining hy the Weigert method.

Between the small commlssiim dorsalis (c.n.) and the large elliptical commissura ventmlis

(c.v.) a large number of non-crossing fibres will be noticed in the " commissure-bed " and

"precommissural area." Of these the postcommissural form the columna fornicis (c.f.).

The precommissural area contains various sets of fibres. The largest group (a) connect

the alveus hippocampi and the basal region of the brain just behind the tuberculum

■olfactorium (f.o.). In Oniif/ior/n/ncf/iis I distinguished these fibres as the " hippocampo-

basal association bundle" *. Other fibres (/3) pass backward below the ventral

commissure to enter the subthalamic region, wliere they become lost. Fibres entering

into the constitution of these tAVO series may be seen in the jjrecommissural area (in the

region marked jj.«.), proceeding from the most anterior i)art of the hijipocampus. Fibres

may also be seen proceeding directly from the olfactory peduncle (and probably bulb)

to enter the fascia dentata (f.d.). This is the olfactory bundle of the fascia dentata (y).

Other fibres belonging to the same series (o) may be seen proceeding backward above

the dorsal commissure as a well-defined tract, probably homologous with the nerve-

fibres of the stria medialis Lancisli of the higher mammalian brain.

In the Marsupial, a typical hippocampal formation lies upon the dorsal aspect of the

commissura dorsalis. In tbis hippocampal formation there are two important series of

longitudinal fibres, Avhich are displayed most clearly in a horizontal section. Such a.

section of the cerebral hemisj^here of Trlchosurns culj)ecula is represented in fig. 11.

In this figure (as also in fig. 2) a large series of longitudinal association bundles are

visible in the stratmii lacunosum. Secondly, in the region of the subiculum (and

possibly in other regions of the hippocampus) large numbers of longitudinal fibres are

contained in the alveus, but in transverse section are not recognizable in the mass of

oblique fibres.

Upon the ventral aspect of the hippocampus in its anterior part we have had occasion

to refer to a large mass of grey matter, the anterior paired region of which we have known

as the " corpus prsecommissurale," and its posterior region as the " commissure-bed."

This region has been the great source of confusion to comparative anatomists, more

especially those working at rej)tilian and amphibian forms, and it therefore demands

a very careful study. Most writers call the whole mass the " septum."

A study of figs. 5, G, and 9, which are all from Perameles, shows that the " commissure-

bed," or matrix of the commissures, extends across the median plane uninterruptedly,

becomes continuous upon its dorsal aspect with the hippocampus of both sides, and

upon its ventral aspect with that thin band {I.e.) of the lamina terminalis which extends

from the ventral commissure to the optic tract (o.tr.). It is connected also in the median

line above with the thin epithelial roof of the third ventricle (a structure not sho^^ n in

the figures). It is clear, therefore, that this matrix, which includes the two commissures,

occupies the situation of the dorsal part of the lamina terminalis, and in part bomids

the third ventricle anteriorly.

* Journal of Anatomy and Physiology, vol. xxs. p. 480.

58 DR. G. ELLIOT SMITH ON THE

If we examine a series of transverse and sagittal sections of a reptilian brain, it will

be found that both ventral and dorsal commissni-es lie in the easily recognizable lamina

terminalis. This lamina contains in the median j)lane a minimal amount of grey matter.

But on either side of the median plane this thin bridge of grey matter becomes

continuous with a huge mass of grey matter which we readily recognize as the

backward continuation of the " precommissural body." Thus in the Reptile the

" commissure-bed " consists of the posterior extremities of the " precommissural arese "

united by the thin grey lamina formed by the lamina terminalis.

In the mammal it is evident that either the grey mass of the " precommissural area"

has invaded, and thus thickened, the lamiua terminalis, which liecomes a continuous grey

mass across the mesial plane, or, on the other hand, the mesial surfaces of the two

posterior regions of the precommissural area may have become " glued " together. One

or other event must have occurred ; and the evidence, I believe, points to a gradual

thickening of the lamina terminalis by the invasion of grey matter from the adjacent

" precommissural area." However the thickening is brought about, we know that the

two cei'ebral commissures of the Marsupial lie in the " commissure-bed," which is

morphologically a thickening of the lamina terminalis. Yet we are equally sure, both

from its topographical relations to surrounding structures and from its minute structure,

that the " commissure-bed " is morphologically part of the same sheet of grey matter as

the " precommissural area."

If the hippocampal region be studied where it bulges in the descending limb of the

lateral ventricle in any Eutherian brain, a considerable variety of the form and relative

sizes of its constituent parts will be apparent. In the Marsupial brain equally great

variations are found in the corresponding region of the hipj)ocampus. But if we

examine the supracommissural part of the hippocampus in a series of Marsupials, the

greatest variety and most varied degrees of complexity are demonstrated. In Notoryctes,

and less markedly in Dcmjiimis, the formation is very simj)le. In Ilacropus it is much

more complex. Perameles is an example of a highly-developed type. Both Monotremes

present in the supracommissural region a more complicated form of hippocampus

than is fovmd in any other mammal. But the anterior extremity of the hippocampus

undergoes the same process of unfolding and simplification in all Marsupials and

Monotremes which I have so briefly described in Ferameles. Hence, should we find a

difference in the relative degree of development of various parts of the hippocampal

formation in the brains of two different animals, we must not lay much weight upon

such differences as an indication of the systemic position of their possessor.

The Mippocampal Region in the J3at.

The cerebrum of the bat may now be studied in the same manner as that of the bandi-

coot. Beginning with a coronal section through the hippocampal region of Miniopteriis

immediately behind the region of tlie commissures, one cannot fail to notice the great

similarity between the two forms (figs. 12 and 1). What differences do occur, apart

from those of al)solute size, point to a less complex form of structure in Miniopterus

(fig. 12) than in Perameles (fig. 1). This simpfication consists of a diminished depth of

OEIGIN OF THE CORPUS CALLOSUM. 59

the hippocampal fissure [f.h.), a less prominent hippocampal eminence in the lateral

ventricle, and a less broad and slightly less convoluted fascia dentata {f.d.). These

variations in the form of the hippocampus are of little moment, for, as I have before

remarked, great variations are found in any order. Moreover, it is noteworthy that in

very small Marsupials like Notoryctes one finds a simplicity of hippocampal formation

similar to that which the miniite Miniopterus presents (compare fig. 6 of my paper

on Notoryctes*).

In the next section, whicli passes through the posterior extremity or splenimn of the

dorsal commissure (PL 16. fig. 13), we have a condition which recalls that presented

by the corresponding section through the brain of Perameles (Pi. 15. fig. 2).

But if we compare the hippocampus in figs. 12 and 13, a distinct simplification will be

noticed in the foremost section (fig. 13). The fascia dentata (f.d.) is narrower, the

layer of pyramidal cells {pyr.) is shorter, and the hippocampus as a whole is distinctly

flatter. In fig. 12 there is a very sharp angle between the alveus and tlie corona

i-adiata, while in fig. 13 the angle has become rounded otF. It is possible that fibres

coming from a wider cortical field may round off the angle, but the carmine stain does

not permit us to definitely decide this. But in the next section (fig. 11) there is

no question, even with the carmine stain, of the much wider field of origin of the dorsal

commissiu'e.

If we are undecided whether any fibres other than hippocampal are passing to the

dorsal commissure in fig. 13, we have in fig. 11 a very distinct demonstration of the

existence of a verv considerable bundle of fibres arisina: from the sjeneral cortex and

forming part of the superior commissure. In fiict, the insignificant flattened band of

grey matter which now represents the hippocampus can contribute but a very small

share towards the formation of the thick commissural tract (c.D.) upon which it lies.

The hippocampus is now much more insignificant and more flattened than it was in the

last figure. The regular row of nuclei immediately above the dorsal commissure belongs

to the layer of pyramidal cells of the hippocampus {pyr.), and the group of closely-

aggregated smaller nuclei which cap the mesial end of the layer of pyramids represents

the stratum granulosum of the fascia dentata. In fig. 15 the region of the fascia

dentata from fig. 11 has been rei)resented upon a larger scale, and in figs. 12, 13, 11,

and 15 the stratum moleculare of the fascia dentata has been shaded in order to render

its recognition more easy.

It will be noticed, if we comj^ai-e figs. 13 and 11, that the commissural fibres of the

general cortex pursue their new course through the alveus of the hippocampus. In

other words, the alveus of the " dorsal hippocam^nis " of the bat consists of a mixture

of fibres derived from the hijijiocampus, which we might call " true alveus," and

commissural fibres derived from the general cortex — "false alveus." Our "false

alveus " is the corpus callosum proper. Prom the examination of this series, therefore,

we may infer that the fibres of the corpus callosum proper reach the mesial platie by

passing through the alveus of the dorsal part of the hippocampus.

* " The Cerebrum of Notoryctes tupldops,"' Transactions of the Eoyal Society of South Australia, vol. xix. pi. viii.

(1895).

60 DE. G. ELLIOT SMITH ON THE

As we proceed forward the supracommissural hippocampus becomes more and more

rudimentary. Had we not been tracing- these structures in a series of sections, we

should never recognize in the few cells situated above the commissures in fig. 16 the

representatives of the fascia dentata {f.d.) and the rest of the hippocampus i])^)'.).

If we were to examine a series of sections further forward we should find, after the

anterior extremity of the dorsal commissure had been passed, that at the junction of the

precommissural area and general cortex (pallium) a few small cells would be found to

represent the hippocampus which is present in the marsupial (fig. 7).

Now that we have seen how the hippocampus is disposed in transverse sections, it

will complete oiu* ideas concerning the commissural region if we study its disposition in

sagittal section. The transverse sections wliich I have figured were those of Jliniojpterus.

The two series of sections of the brain of Nyctophilus, which would have served our

purpose even better, were not exactly transverse, and therefore might be confusing.

It may be remarked, however, that the " iion-hippocampal " element in the dorsal

commissure is even less developed in Nyctophilus than it is in the single specimen of

Minioptcrus which I have examined. I have made several series of sagittal sections

of the brain of Nyctophilus, and, for illustration, a section slightly to the side of the

middle line has been chosen in order to show the relation of th(; hippocampus

to the " splenium " of the dorsal commissure, A section passing through the mesial

plane presents no difi'erence in the appearance of the commissures from that presented

in fig. 17.

In this section (fig. 17) we cannot fail to be struck with the resemblance to the

Marsupial. The relatively enormous size of the ventral commissure (c.v.) and the shape

and proportions of the dorsal commissure (c.D.) are strongly suggestive of the Metatherian

structures. Yet in no Marsupial are the two limbs of the commissure so broadly

expanded. For the ventral limb (c.D.") is nearly vertical, and the dorsal limb (c.D.') nearly

horizontal, so that the angle included between the two limbs is not far short of 00". Of

the two lim1)s the ventral is the larger. Both limbs become thicker as they are traced

towards their place of union, where they form a massive " splenium." Immediately

behind the splenium in this section we see the fascia dentata {f.d.) cut very obliquely,

and extending forward from the concavity of the pouch formed by the stratum

granulosum the layer of pyramidal cells of the hijjpocampus {hip.) immediately above the

dorsal commissure.

The " commissure-bed " (s) enclosing both commissures fills up the great interval

between the two limbs of the commissura dorsalis and tlie commissura ventralis.

In the dorsal limb of the commissura dorsalis (c.i).') I have represented by means of dots

the position which a study of transverse sections leads me to regard as approximately

those occupied by the commissural fibres which do not spring from the hippocampal

formation, i. e. by the fibres of the corpus callosum proper. From this we see that the

anterior extremity of the dorsal limb is almost purely " callosal " — if we may use such a

term. The transition from pvirely " callosal " to purely " hi2)i)ocampal " parts of the

commissure is a very gradual one, " hippocampal " and " non-hippocampal " fibres being

intimately mixed one with another at the place of junction.

ORIGIN OF THE CORPUS CALLOSUM. 61

Tims it icould appear that in this bat cominissural fibres arising from a very restricted

area of the dorso-mesial cortex above the supracommissural region of hippocayrtpus,

instead of passing by the circuitous route via the external capsule and through the

ventral commissure, pass through the alveus of the supracommissural hip)p)Ocampus to

reach the opposite hemisphere through the dorsal limb of the dorsal commisstire. In

other icords, fibres tohich do not </rise in the hippocampal formation jjass through the

alveus of the hippocampus to become commissural, and, as a result of the consequent atrophy

of the in faded region of hippocampris, the invading fibres ustirp the place previously

occupned by the anterior part of the hippoeamp)al commissure.

The " usurping fibres " are the " corpus callosum, and the atrophic hippocampus

forms part of the " inclusium " and " striae Lancisii."

The relation of the rudimentary corpus callosum to the hippocampus, to the " cora-

missure-bed," and to all the surrounding structures is identical in every respect with that

which the corresponding part of the hippocampal commissure presents in the Marsupial.

We have no reason to regard the " commissure-bed " in the bat in any other light than

as the strict homologue of the structure which we have designated by that name in the

bandicoot. For even though the large mass of hipjiocampal cortex is wanting upon the

dorsal aspect of the commissure, it cannot have been absorbed into and swell the mass of

the " commissure-bed," for its vestiges are clearly and indubitably present, as we have

just seen, upon the dorsal aspect of the " commissura dorsalis." Since our new

commissure or corpus callosum lies entirely upon the ventral aspect of the hippocampus,

it must be still contained in the " commissure-bed " (or possibly the " corpus prtc-

commissurale ") just as in the Marsupial.

General Considerations.

We have now contrasted the hippocampal region of a typical Marsupial cerebrum

with that of certain Cheiroptera as types of an extremely low grade of Eutherian

organization. I propose now to In-iefly discuss the significance of the differences observed,

and their special bearing upon the question of the origin of the corpus callosum.

Fig. 1 (p. 63) represents in a schematic manner the position which tlie hippocampus

occupies in the mesial wall of the hemis})here of a Marsupial. This hippocampus may

be roughly divided into three segments: — {a) a "precommissural segment" [hipj"),

which lies in front of the commissures and sejiarates the precommissural area [p.a.)

from the general cortex {p) ; {b) a " supracommissural segment " {hip'), which lies

above the dorsal commissure, whose dorsal limb separates it from the " commissure-

bed " (s) ; and (c?) a " postcommissural segment," which constitutes the greater part of

the hippocampal formation and possesses a true fimbria [fi).

These three segments of the hippocampus form an extensive arc, reaching from the

olfactory bulb {o.b.) in front to the lip of the temporal pole {t) behind and below. The

" commissura dorsalis " derives its fibres from this extensive arc. [The few fibres

springing from the precommissural body \\ hich probably enter into the constitution of

the dorsal commissure may be disregarded in this discussion.] The commissural fibres

62 DE. G. ELLIOT SMITH ON THE

derived from the precommissural and supracommissural segments form the dorsal limb,

and those derived from the postcommissural segment form the splenium and ventral

limb of the " commissura dorsalis."

Now, we have seen that in the brain of the bat commissural fibres arise from a small

area of the mesial cortex, which is distinctly not hippocampal, but which is placed above

the hippocampus, and that, after passing through the alveus of the svipracommissural

hippocampus, they cross the mesial plane intimately intermingled witli the hippocampal

fibres of the dorsal limb of the " commissura dorsalis." Coincidently with this invasion of

the alveiTS, and possibly as a direct result of it, retrogressive changes occur from before

backward in the " precommissural " and " supracommissural " segments of the hippo-

campus. So that soon these parts of the hipiiocampus {hip' and h'qf) are reduced to

mere vestiges, which, however, may still retain their characteristic histological elements.

These vestiges are the so-called strise Lancisii (mesial and lateral) and the associated

film of grey substance. It is natural to suppose that with the retrogressive changes

in the supracommissural hippocampus the liippocampal factor in the dorsal limb of the

dorsal commissure wanes, so that the usurping pallial fibres remain practically

if not actually unmixed with hippocampal fibres, to constitute the dorsal limb of the

dorsal commissure.

This change is so gradual, and the pallial invasion so insidious, that at first the

appearance of the commissures is unchanged, as in Nyctophilus, from our Marsupial type,

and we are apt to overlook the fact that there has been thus introduced " the greatest

modification exhibited by the brain in the whole series of vertel)rated animals," as

Huxley has said. It is unnecessary to discuss the question of the homology of these

pallial fibres in the dorsal commissure ; for, in the ' Transactions of the Linncan Society

of New South Wales,' I have already (October 1894) called attention to the fact that

while in the Marsupial the whole pallium is bound to its fellow of the opposite hemi-

sphere by means of fibres of the ventral commissure, in the Eutherian hemisphere part

of the homologous pallium sends its commissural fibres by the much shorter route which

the commissura dorsalis provides. Therefore we cannot regard the corpus callosum as

an entirely new group of commissural fibres, but rather as fibres the undoubted homo-

logues of which arc found in the ventral commissure of the Metatherian cerebrum. The

passage of these pallial fibres through the dorsal commissure is an adaptive feature

which is obviously advantageous to the organism, since the new route provides a very

considerably shorter and more direct path for the commissural fibres of the rapidly-

increasing dorsal part of the palliiun. It is not at all sur2)rising, therefore, to find a great

and rapidly-growing demand upon this advantageous pathway oid the dorsal limb of the

dorsal commissure. Thus quite early this dorsal limb becomes completely transformed

from a practically purely "hippocampal" to a practically purely "paUial" structure.

(In fig. 1, p. 63, this reconstructed limb of the commissure has been darkly shaded.) But

the continued crowding in or intussusception of new commissural fibres soon expands the

bulk of the dorsal limb not only in thickness, but also in length. At first the increase in

length is most noticeable in the caudal direction, in correspondence with the rapid backward

growth of the hemisphere. This backward extension of the commissru^e takes place in the

OEIGIN OF THE CORPUS CALLOSUM.

63

plane in which the dorsal limb already lies. Xow this plane is directed backwards and

upwards, as indicated by an arrow in fig. 1.

What are the effects of sucli a backward extension upon the hippocampus ? The

/>c. /.

F/c.Z

F/a

Fig. 1. — Scheme to show the arrangement of the hippocampus in the mesial wall of the hemisphere of a Marsupial.

The darkly-shaded part represents the first corpus eallosum, such as is found in Miiuojjtenis, and the arrow

indicates the Une of its backward extension in the higher Mammals.

Fig. 2. — Scheme of the corresponding region of a more highly developed cerebrum, such as that of Pteropus.

Fig. 3. — The " spherical " region from fig. 2 on a larger scale.

remains of the hippocampus which cover the dorsal aspect of the corpus eallosum are

stretched, and thus further attenuated, by the lengthening commissure. The backward

growth of the commissure, owing to its obliquity, soon indents the hippocampal

formation just at the junction of the atrophic " supracommissural " segment with the

SECOND SERIES. — ZOOLOGY, VOL. VII. 10

64 DE. G. ELLIOT SMITH ON THE

uaaltered " postcommissural " segment. This indentation soon increases and becomes a

very extensive bend, the portion of the hippocampus which surrounds the posterior

extremity of the dorsal commissure being carried backward and greatly stretched (fig,. 2).

In this way the obliquely-directed commissure fi.rst of all pushes upward and backward

the hippocampus at the junction of supra- and postcommissural parts, stretchiug and

carrying back the part of hippocampus that invests it above the rest of tlie j^ostcommis-

sural hippocmnpus. The " postcommissural hippocampus " (fig. 3, hip) thus appears tO'

become subcallosal and to be separated in the vertical plane from the splenium of the

dorsal commissure {s})!) and the circumsplenial portion of the hippocampus {hip') by a

process of pallium (figs. 2 and 3, *) ujjon which Zuckerkandl has laid so much stress

under the confusing name " Balkenwiudvmg." (It will be remem1)ered that it was

the lack of this feature which, in part, led him to group a bat with Marsupials and

Monotremes).

As a result of the operation of the above-mentioned factors, therefore, a somewhat

reversed S-shaped bending is produced in tlie hij^pocanipus at the jimction of its middle

and posterior segments. The upper part of the S with its concavity looking forward is

formed by the attenuated hippocampus (fig. 3, hip') surrounding the splenium (fig. 3, spl),

while the lower part of the S, which is convex in front, is formed by a " sul)splenial "

bending of a plumper hippocampal region, whicli I have distinguished as the " hippo-

campal flexure " {fl^c)-

Throughout all these changes tlie main mass of the ventral limb of the dorsal com-

missure (CD.") has remained unchanged.

In the Marsupial and in a large number of lowlier Eutheria the plump ventral limb

extends obliquely upwards to meet the dorsal limb in a thick splenium. But when the

dorsal limb extends further l)ackward, the main mass of the ventral limb is left in

its old position (fig. 2, c.d."), its postero-supcrior extremity becoming greatly stretched

and correspondingly thinned by tiie backwardly-extending corpus callosum.

The fimbria maintains its position unchanged (figs. 1 and 2,_7^") and always lies upon

the posterior or inferior aspect of the corpus callosum. In its backward growth the

corpus callosum carries back its matrix or " commissure-bed," in which it always lies.

But although the elongation of tiie corpiis callosum is most obvious in tlie backward'

direction, it also groA^ s forward towards the anterior extremity of the brain.

In the Amphibia and certain Reptiles, Avhere the olfactory bulb is placed in front and

is not overlapped by the hemisphere, the " corpus prgecommissurale " extends forward as

a horizontal baud from the lamina terminalis to the mesial wall of the olfactory peduncle.-

It is bomuled upon its dorsal aspect by the homologue of the hippocampus. In the

Marsupials with small pallia the upper margin of the precommissural body is slightly

oblique (PL 15. figs. 8 and D). As the pallium increases in extent it bulges over the

olfactory bulb (figs. 1 and 2, p. 63) more and more, and consequently the " precommis-

sural " hippocam])Us {hip") becomes more and more oblique, because it always extends

towards the olfactory peduncle. Thus the hippocampus comes to bend downward iu;

front of the commissures. Now it is obvious that the dorsal limb of the commissura

dorsalis (fig. 1), if it extends forward, must indent this precommissural segment of the

OKIGIN OF THE CORPUS CALLO.SUM, 65

hippocampus as I have represented in fig. 2. This anterior portion of indented hippo-

campus is the "gyms grnicuW' of Zuckerkandl.

It is ai:)parent from this that the dorsal comiiiissure, which in. the Ilarsupial liesroithin

a well-defined arc formed by the hippocampus (fig. 1), never breaks through this hippo-

campal arc even in its much more extended and reconstructed form as a corpus callosum,

but pushes the dorsal part of the arc before it as it elongates in. both directions (fig. 2).

We have seen that in tlae Marsupial a large mass of grey substance, containing both

commissures and formed by the "corpus prfecommissurale " and "commissure-bed," is

situated i;pon the ventral aspect of this hippocampal arc. Since the hijipocampal

formation may be recognized surrounding the corpus callosum even in the brains of the

ox, the monkey, and man, it is clear tliat the matrix of this commissure can be formed

of no other structure than the " precommissural body " and the " commissure-bed."

This introduces us to the problem of the nature of the " septum pellucidum."

We have already seen that the first " callosal " fibres rej)lace the hippocampal fibres of

the dorsal limb of the " commissura dorsalis," and in every respect joresent the same

relations as the fibres, the places of which they usurp. The first " callosal " fibres,

therefore, must lie in the structure which is exactly homologous to what we have

called, in the Marsupial, the " commissure-bed."

In discussing the natiu"e of the " commissure-bed " we came to the conclusion that

with the increasing dimensions of the commissures the dorsal part of the lamina

terminalis became thickened or invaded by the posterior parts of the " corjjora prte-

commissuralia," so that a bridge of grey matter — the " commissure-bed " — was formed,

connecting the two hemispheres, and forming a matrix for the two cerebral

commissures. This secondaiy thickening appears to take place gi-adually in the

ontogeny of each individual, and cannot be regai'ded as a mere mechanical fusion of the

precommissural areoe of the two hemispheres. We may therefore safely say that the

dorsal commissure of the Metatherian and (for the reasons stated aljove) of the early

Eiitherian cerebrum is contained in a matrix which is formed by a thickening of the

dorsal part of the lamina terminalis at the expense of the " corpora praecommissuralia."

As new commissural fibres crowd in aud the commissure increases ia length and depth,

this matrix becomes extended, but I believe it always continues to enclose the dorsal

commissure, even in its most extended form.

Paul Martin says tha in the cat the cephalic extremity of the corpus callosum or

genu is formed by the apposition of fibres in front of those which are situated in the

thickened lamina terminalis. It must be evident (if we glance at fig. 1) that if these

apposed fibres grow in a " secondary fusion of the walls of the hemisphere," such a

fusion must consist of a " soldering " of the two "precommissural hippocampi" {hip").

But such a " soldering " does not take place, because in the gyrus genicuU we have seen

the representative of the " precommissural " hippocampus pushed before the advancing

corpus callosirm. There seems to be no other .alternative which could be for a moment

maintained but that the corpus callosum is contained ui its original matrix or " com-

missure-bed," which has become enormously but gradually elongated. This conclusion

is strongly forced upon us by comparison, in the order mentioned, of such a series of

10*

66

DR. G. ELLIOT SMITH ON THE

cerebra as those of the Iguana, Ornithorhynclnis^ Phascol-

arctos, Perameles, Nyetophilus, Dasypus, and Talpa, with

more highly-developed forms.

In this process of forward extension the dorsal com-

missure has carried forward its oAvn matrix, derived from

the original " commissure-bed." It is obvious that if this

takes place withovit a corresponding growth of the bridge

of grey matter {s) which lies between the dorsal and ventral

commissiu'es, we shall have pai't of the great longitudinal

fissure (botmded on either side by the precommissural area)

roofed in by the corpus callosum (contained, of course, in its

proper matrix). This roofed space will be bounded posteriorly

by the ventral limb of the " commissura dorsalis." This

enclosed part of the great longitudinal fissure is the so-

called "fifth ventricle^'' or " cavitm septi pellucUli."

By means of the accompanying five schemes (in which the

commissure-bed is shaded) T have graphically represented

different stages in this process. From these schemes it

will be readily recognized how the backward extension of

the dorsal commissure (fig. 8) stretches not only the matrix

in which it lies but also the sheet of the " precommissiiral

body " {p.a.) which fills up the large angle between the two

limbs of this commissure. Thus a portion of the pre-

commissural body of each hemisphere becomes one of the

leaves of the septum pellucidura. In liis valuable memoir

Paul Martin speaks of a fusion taking place (in the brain

of the cat) between the opposed walls of the hemisphere

on the ventral side of the corpus callosum. In tliis manner,

in the more highly-developed macrosmatic Eutherian

cerebra, the massive corpora praecommissuralia below the

corpus callosum may meet and fuse in the median plane

so as to obliterate the cavum septi. But the commissure

itself is not situated in anv such secondary fusion of the

hemisphere walls, so that it does not aff'ect the main

argument advanced above.

But though the coi-pus praecomraissui'ale thus takes an

important share in the formation of the septum pellucidum,

part of it always remains distinct in the higher mammalian

cerebrum as a vertical band, lying parallel to the lamina

terminalis and separating the latter from the general pallium.

This band is the "gyrus subcallosus " of Zuckerkandl. In

order to show the last stage which this process reaches, I

have represented in PI. 16. fig. 18 this region of the cerebmm

/="/c. -?-

Fie. 5.

nc.e.

Fic. 7.

F'<^

Figs. 4-8. — Schemes to explain the

evolution of the " septum pellu-

cidum."

Fig. 4 is a type of a Reptile.

„ 5 ,, „ Monotreme.

„ 6 „ „ Marsupial.

OEIGIN OF THE COEPUS CALLOSUM. 67

of an adult man. The anterior extremity of the corpus callosum has become so bent

that its rostrum (r.) becomes continuous with the remains of the " commissure-

bed," which still surrounds the ventral commissure (c.v.). In this way the septum

pcUucidum {sept.) becomes surrounded by a complete ring of the matrix of the

commissiu-es and cut off from the gyrus subcallosus, which is the remainder of the

precommissural area. This gyrus subcallosus extends down to the base of the cerebrum

immediately in front of the ventral commissure and lamina cinerea {I.e.). Its line

of separation from the pallium is indicated in the figure by a dotted line {a.l.).

The gyrus subcallosus is traversed by a well-marked vertical depression — the Jissm-a

jirima {fiss.])!'.), — Avhich has no important morphological significance.

With the knowledge which we have acquired of the process of phylogenetic

development of the region of the commissures, it is extremely instructive to study

the beautiful figures with which Marchand, in man, and Paul Martin, in the cat,

represent {op. cit.) the process of ontogenetic development.

In the Marsupial we have a fissura arciiata or hippocampi, extending from the

tip of the temporal pole right round the mesial wall of the hemisphere towards the

olfactory pedimcle ; so, in the foetal child or kitten, we find the Bogenf urche (wliich we

might, with Mihalkovics, appropriately call " Ammonsfurche ") following a similar course

and shading away towards the cephalic pole of the hemisphere. And it is necessary to

remark, in passing, that the so-called part of the " vordere Bogenfurche," which His

calls " fissui'a j)rima," has noticing whatever to do with the true Bogenfurche or

fissura arcuata, if we regard the latter as the primitive fissura hippocampi.

In the early stages of the cat, the lamina terminalis becomes thickened and invaded

by the commissural fibres of the fornix (Paul Martin), so in phylogcny we have the

corresponding stages in the adult Monotremes and Marsupials.

Then, as the commissural fibres increase in number, the grey mass or thickening of

the lamina terminalis is invaded by so many white fibres that the grey substance seems

to disappear, but it is in reality being gradually extended by the swelling commissure.

The backwardly-extending commissure produces exactly the same series of changes —

the same hippocampal flexure — in our phylogenetic series as it does in the developing

brain of the cat and man (see Martin and Marchand's figures).

Thus, for oil the stages in the developing brain of the cat, we can find almost exact

prototypes among the more lowly-developed mammals.

The great feature which far more than any other distinguishes the mammalian brain

from that of all submammalia is the possession of a definite pallium — -distinct alike

in its histological features and its morphological relations — giving rise to a definite

internal capsule of projection-fibres and well-defined and fully-medvillated commissural

fibres. At first, in the Monotremata and Marsuj)ialia, this pallium (like the parent mass

of the basal ganglion from which it ajipears to have sprung) is united to its homologue

of the opposite hemisphere by means of the " commissura ventralis " — " the commissure

of the cerebral hemisphere " par excellence.

But the rapid growth in extent and complexity of this general cortex or pallium

is accompanied by a richer and more abundant commissural system. This growing

commissural system from the dorsal part of the enormous pallium not only finds in the

68 DK. a. ELLIOT SMITH ON THE

" commissura clorsalis " a shorter path, but a clearer scope for longitudinal extension

than the ventral commissure provides. And tlms we have pallial fibres invading and

subsequently superseding the dorsal limb of what was previously the hippocampal

commissure.

" Pallial " commissural fibres probably first make their appearance in Eeirtiles and

form a very insignificant constituent of the ventral commissure. In Monotremes and

Marsupials these fibres become extremely abundant, and swell the proportions of the

ventral commissure enormously. But in Eutheria a rapidly increasing proportion of

these fibres forsake the commissura ventralis and form the new " dorsal commissure of

the pallium " — the corpus callosum, — which throws the " parent " commissure into

insignificance. The remnant of the commissura ventralis is known in man by the

somewhat misleading name " anterior commissure."

EXPLANATION OE PLATES 15 & 16.

Fig. 1. Coronal section througli the forebrain of Peranicles nasuta. Stained by Weigert's method.

X4. The section passes just behind the commissures.

2. Coronal section through the hippocampal formation and the posterior extremity of the " com-

missura dorsalis^' in Peramehs. Wcigert stain. Fascia dentata represented as it appears

after nuclear staining, x 20.

Figs. 3 & 5. Coronal sections of the " commissura dorsalis " of Perameles, a short distance in front of

fig. 2. X about fi.

Fig. 4. Representation of the commissures of Pernmek's (as seen in a mesial sagittal section) to show

the planes in which the sections represented in figs. 2 («), 3 {b), 5 (c), and 6 (d) w-erc cut.

6. A coronal section of the cerebral hemispheres of Peram,eles, to show the general arrangement

of the commissures. Wcigert stain, x about 6.

7. Coronal section of the right cerebral hemisphere of Perameles immediately in front of the

cerebral commissures. Weigert-Pal and carmine stains, x 4.

8. Semi-schematic representation of the anterior part of the mesial wall of the cerebral hemisphere

of Dasyurus vivervimis. X about 4. To show that, as a result of the unrolling of the hippo-

campus anteriorly, the whole of its morpholoyicully superficial layer now actually forms part

of the visible surface. Thus the surface of the hippocampus proper [hip.'") appears above the

fascia dentata [f.d.').

9. Anterior portion of the forebrain of Perameles, exposed in a mesial sagittal section. x 4^.

The bulbus olfactorius only represented in part and in outline.

10. Sagittal section through part of the anterior portion of the mesial wall of the cerebral

hemisphere of Phascolarctos cinereus. Weigert stain. X G.

11. Horizontal section through the left hemisphere of T/'icAosf^n/s ?;M/yje'c«/«, a short distance above

the commissures, x 2. ant.mcs., the antero-mesial angle.

12. Coronal section through the right hippocampal formation of a bat [Miniopterus Schreibersii) , to

compare with tlie hippocampal region of fig. 1. Lithinm-carniine stain. x about 20.

13. Coronal section o? Mi/iiopterus. Compare fig. 2.

14. Coronal section of right hemisphere of Miniopterus. X about 20. Compare with fig. 6.

15. The fascia dentata and adjacent parts. Enlarged from fig. 14.

16. Coronal section of the liippocampal region of Miniopterus, a short distance in front of fig. 14.

17. Sagittal section of the commissiires and adjacent parts of brain of Nyctophilus near the mesial

plane. X about 40.

18. Drawing of the " gyrus subcallosus " of a human bram.

OEIGIN OF T]IE COEPUS CALLOSUM.

69

ExplaHation of reference-lettei

The significance of tlic reference-letters a, h, c, d, a, ^, y,

a. I. Anterior limit of the " gyrus subcallosus.''' /.

ali\ Alveus hippocampi.

ciny. Cingulum. I.e.

ciny' . Longitudinalfibresin the alveus hipjjocanipi l.v.

adjacent to the cingulum. n.a.

C.I). " Commissura dorsalis." n.c.

CD.' Dorsal limb of the " commissura dorsalis." n.f.d.

c.d". Ventral limb of the iMetatherian type of n.l.

" commissura dorsalis." o.b.

c.e. Capsula externa. o/;/.

c.f. Columna fornicis. o.tr.

c.i. Capsula interna. p.

cm. Commissura mollis. p.a.

c.r. Corona radiata.

est. Corpus striatum. PJ/-f-

c.v. " Commissura ventralis." pyr.

d.f. Uesceudiug hippocampal or fornix-fibres.

e. Epithelial fold roofing the third ventricle. r.o.

e.o.t. External olfactory tract. s.

f.d. Fascia deutata. sept.

f.h. Fissura hippocampi. s.^r.

fi. Fimbria. s.l.

fi. The remains of the fimbria intermingled s.m.t.

with fibres of the commissura dorsalis. spl.

fix. The " subsplenial hippocampal flexure." s.r.

f.r. Fissura rhinalis. s.t.

g.h. Ganglion habenulte (and stria meduUaris s.t'.

thalami).

hip. Hippocampus. s.t".

hip' . " Supracommissural hippocampus." sub.

hip". "Precommissural hippocampus." t.

hip'". Stratum zonale of the " precommissural

hippocampus" lying upon the surface im- t.o.

mediately above the stratum zonale [vd v. 3.

molecularej of the fascia dentata [f.d.'). x.

i. " Indusium vermn."

i.l.s. Internal limiting sulcus of the tuberculum y.

olfactorium {t.o.).

•s in tlie Jigitfcs.

h is explained in the text.

" Longitudinal association bundles " of the

hi[i2i{icampus.

Lamina cinerca.

Lateral ventricle.

Nucleus amygdalae.

Nucleus caudatus.

Nucleus fasciae dentatae.

Nucleus lenticularis.

Olfactorj' bulb.

Optic nerve.

Optic tract.

General cortex or pallium.

"Precommissural area" or "corpus prm-

commissurale."

Pyriform lobe.

Layer of pyramidal cells of the hippo-

campus.

Recessus ojiticus.

" Commissure-bed."

" Septum pellucidum."

Stratum granulosum of the fascia dentata.

Stratitm lacunosum of the hippocampus.

Stria medullaris thalami.

Splenium of the corjjus callosum.

Stratum radiatum of the hippocampus.

Stria terminalis.

The crossing fibres of the stria terminalis

entering the " commissura ventralis."

The uncrossed part of the stria terminalis.

Subiculum cornu ammonis.

"Temporal pole" of the cerebral hemi-

sjjhcre.

Tiiberculum olfactorium .

Third ventricle.

MeduUated nerve-fibres

stratum lacunosum.

" Tract us hippocampi ad pallium."

going to the

Elliot Smith

Trans Linn Soc Zool See 2,Yol.V1I,Pl 15

e.o I.

rHiitK.Lith'Edin'

HIPPOCAMPAL REGION OF BRAIN IN PERAMELES AND DASYURUS.

Elhol Smith

Trans Linn Soc Zool Ser 2,Vol VII.Pl 15

FHuth,Lilh'Edii!'

HIPPOCAMPAL REGION OF BRAIN IN MARSUPIALS AND CHEIROPTERA.

LINNEAN SOCIETY OF LOiNDON.

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2nd Ser. ZOOLOGY.]

[VOL. VII. PART 4.

AUG 17 1893

THE

io^lL

TRANSACTIONS

OF

THE LINNEAN SOCIETY OE LONDON.

ON THE MUSCULAR ATTACHMENT OF THE ANIMAL TO ITS SHELL

IN SOME FOSSIL CEPHALOPODA (AMMONOIDEA).

BY

GEORGE CHAELES CRICK, F.G.S., F.Z.S.,

OF THE BRITISH MUSEUM (NATURAL HISTORY).

{Communicated by the President, Dr. A. Gunther, M.A., F.R.S.)

LONDON:

PRINTED FOR THE LINNEAN SOCIETY

BV TAYLOR AND FRANCIS. RKI) LION COURT, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOnSE, PICCADILLY, W.

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

^ June 1898.

AUG 17 1893

r 71

IV. On the Mnscnlar Attachment of the Animal to its Shell in some Fossil Cephalo])oda

[Ammonoidea). By G. C. CmcK, F.G.S., F.Z.S., of the British Iliiseum [Natural

Sistory). [Communicated l»j the Piiesident.)

(Plates 17-20.)

Read 3rfl February, 1S!)8.

INDIC^ITIONS of the muscular attachment of the animal to its shell have been

tigured in not a few Nautiloids, but comparatively few Ammonoids have been recorded

in which what has been believed to be the remains of this attachment has been iigured

and described. Of these the best known are Oppel's figures of three examples of

Ammonites steraspis* from the Lithographic Stone of Bavaria, iiublished in 1863, in

which the body-chamber of each is shown to be traversed by a fine curved line, the

relation of which to the animal was not, however, indicated by the author.

In 1870, Trautschold f figured a specimen of Ammonites hicurnatus, exhibiting what

he considered to be the impression of the muscular attachment of the animal, but this

figure differs considerably from Oppel's figiu'cs.

In the following year, Dr. W. Waagen % published his important paper, " Ueber die

Ansatzstelle der Haftmuskeln beim Nautilus und Ammonoiden," in which he expressed

his opinion that the " shell-muscle " in the Ammonoidea was attached to the inner

(umbilical) portion of the lateral area of the whorl. He believed the curved line

figured by Oppel on the body-chamber of Ammonites steraspis to be a trace of the

" annulus," and probably also of the shell-muscle, and, reproducing one of Oppel's

figures, he completed by a dotted line what he considered to be the form of the shell-

muscle. This interpretation of Oppel's figures has been accepted by most authors.

In 1879, Eck § figured and described a small septate fragment of Ceratites semipartitus

from the Upper Muschelkalk of Schwielierdingen, near Stvittgart, Avhich he thought

showed not only the appearance of the surface of the mantle (the so-called " epidermids "),

but also the impression of the annulus. The specimen was merely an internal cast of

five chambers, and on the surface of the cast of each chamber there was a depressed zone

with a finely-pitted surface, occupying on the siphonal region the middle two-thirds, and

becoming much narrower on the side of the whorl ; in two of the chambers a groove was

also present on the antisiphonal area.

* Pal. Mittheil. p. :2.j1, pi. Ixis. figs. 1, 2, & 6 (1863).

t Bull. Soc. Nat. Moscou, vol. xliii. pp. 301-306 (1870).

t Pateontographica, vol. xvii. pp. 185-210, pis. xxsis. & xl. (1871).

§ Zeitschr. deutsch. geol. Gesell. vol. xxxi. p. 276, pi. iv. figs. 5 a-d (1879).

SECOND SERIES. — ZOOLOGY, VOL. VII. 11

72 MR. G. C. CRICK OX THE MUSCULAR ATTACHMENT OF THE

In his lai'ge works on the Triassic Cephalopoda, Dr. E. von Mojsisovics * has figured

several species of Ammouoids bearing on the internal cast of their body-chamber a groove

or grooves (extending in some examples from the umbilicus on one side, over the

peripliery, to tbe umbilicus on the other side), vrhicli he considered to be the impression

of the homologue of tiie muscular attachment of the recent Nautilus.

Dr. O. Jaekel t, in 1889, figured a Ceratite from the Trias of Riidersdorf, near Berlin,

bearing a groove precisely similar to those figured by Dr. E. vou Mojsisovics, and

although he douljted this indicating the position of the homologue of the annukis

and of the shell-muscle in the recent Nautilus, he was unable to give any explanation

of its nature. After an examination of Oppel's original specimen, this author says the

line which Oppel figured and which has been regarded as indicating the position of the

anterior boundary of the anuulus and of the shell-muscle can scarcely be folloAved with

certainty, and he is inclined to doubt tiie correctness of the interpretation.

In his ' Vorlaufige Mittheilung liber die Organisation der Ammoniteu ' +, Dr. Stein-

mann evidently does not agree with Dr. Waagen's interpretation of Oppel's specimens

(although he seems to make no special reference to them), a fact which is clearly brought

out in the ' Elemente der Palaontologie ' (1890) by himself and Doderlein, where (p. 351,

fig. 402) one of Oppel's figures (Pal. Mittheil. pi. Ixix. fig. 2) is reproduced, and tbe

curved line on the body-clianiber completed in the manner suggested by Waagen, but in

the explanation of the figure this line is thus described : " (?) vordere Greuze des

Haftbandes."

At the meeting of the Geological Society of London which was held on March 25th,

1891, a communication was read from Mr. S. S. Buckman, entitled " Notes on Nautili

and Ammonites." Only an abstract of the paper was published §. Nautili and

Ammonites were exhibited in illustration of the paper, and, according to the abstract,

" Two specimens exhibited show long spatulate depressions more or less parallel to the

periphery for about half the length of the body-chamber. It was suggested that these

impressions indicated the position of the shell-muscles."

So far, then, as I have been able to ascertain, no satisfactory examples exhibiting the

form and position of the musctdar attachment of the Ammonoid animal to its shell have

yet been figured and described either to confirm or to contradict the explanation whicli

AVaageu gave of Oppel's figures.

The Ammonite animal may have been, and prol)ably a\ as, attached to its shell at the

edge of the last septum, as in the living Nautilus, but from my own observations it is

* Abhaudl. d. k.-k. geol. Eeichsanst. Wieii, Bd. vi. Theil i. Heft i. (1873) pi. xvi. f. 3 {Phi/lloceras occidfum) ;

pi. xix. f. 1 (Pinucoceras transiens) ; pi. xix. ff. '2, 3, 4 & pi. xx. ff . 8 &: 9 {Pmacoceras Jiumile) ; pi. xx. ff. 2, 3, 5, &

7 (Pivxicoceras insectum) ; [il. xxii. ff. 7, 8 {Pi nacoceras mi/ophorum) ; ibid. Bd. vi. Hiilf'te ii. (1893) pi. cxxxiv. f. 1

{Choristocei'fis amiiwnh'ifornu); ihUl. Bd. x. (1882) pi. liii. f. 2 (Mec/aj}hi/lKtes sandalinus); pi. liii. f. ;5 {Mega-

phyllites oholus).

t " Ueber eineu Ceratiteu aus dem Schaumkalk vou lliider.sdorf uud iiber gewisse als Haftring godeutete Eindriicke

bei Cephalopoden," Ncues Jahrb. 18S9, ii. p. 19, pl.i.

+ Berichtc der naturforsehendcu Gesellschaft zu Freiburg, Bd. iv. Heft 3, jip. 31-47 (1889).

§ Abstr. Proc. Geol. Soc. Loudou, Session 1890-91, p. 105 (Quart. Journ. Geol. Soc. vol. xlvii.).

ANIMAL TO ITS SHELL IN SOME POSSIL CEPHALOPODA. 73

quite clear that it was furnished with shell-muscles and an annulus like the recent

Nautilus, and it is the object of the present communication to record the indications of

these structures in various Ammonoids. It is not proposed here to record every

Amnionoid in which these imj)ressions have been observed — this I hope to be able to

do subsequently — but to describe the form and position of these impressions so far

as I have been able to observe them in the different forms which the Ammonoids

assume, e.g. in BacnUtes, Hamitcs, Crloceras, Ancylooeras, Macroscapliites, Scaphites,

and Tiirr/lHes, the group of the Ammonites (ranging from very evolute to almost

entirely involute forms), as Avell as in Chjmenia and the group of the Goniatites.

It may be well at the outset to refer to the indications of the shell-muscles and of

the annulus as they exist in the shell of tlie recent Nautilus, and for this purpose it

will probably suffice among the many figures which have been published of the m.uscular

attachment of the I'ecent Nautilus to call attention to the figures accompanying

Dr. Waagen's paper already alluded to (p. 71)*. I may, however, here remark that

in the recent Nautilus the shell-muscles are ear-shaped and situated upon each side of

the animal ; they are connected both on the dorsal and on the ventral side by a narrow

band — the annulus. The shell-muscles are not inserted into the shell-substance, but

are merely applied to the innei* surface of the test with the intervention of a thin layer

of conchiolin ; and all that is usually preserved in the interior of the shell to indicate

the form and position of the muscular attachment is a fine, generalh' raised line, corre-

sponding to the anterior boundary of the annulus and of each shell-muscle; it is

only rarely that there are any indications of the posterior boundary of these structures.

On an internal cast this raised line would be represented by an incised line, and since in

fossils the remains of the muscular attachment are preserved almost always on internal

casts, they therefore exist as incised lines. Such structures have been described and

figured in not a few fossil Nautiloids, including the genus Nantilns itself. In the fossil

forms any recoi'd of the form and jiosition of the muscular attachment would, when

present, usually be preserved iipon the surface of the natural internal cast of the body-

chamber, and hence raised lines on the inner surface of the original test would appear

on the internal cast as incised lines, and clce versa.

In order to observe in the recent Nautilus the exact position of the muscular attach-

ment with relation to the edge of the last septum, an artificial cast of the shell ot

Ndiitilvs pompilius w^as made by filling a sagittal section of a recent shell with paraffin

wax, and then dissolving aw'ay the shelly matrix with hydrochloric acid. The anterior

boundary of the muscular attachment alone was indicated by a very finely incised line.

To show the usual position of the muscular attachment in Ammonoids, and for the

better understanding of the less perfectly preserved examples, it is proposed first to

describe the impressions of the " muscular scars " in the specimen on which they have

been most clearly seen, and then the specimen in which the remains of the annulus

have been most clearly observed. The former is an example of Crloceras from the

* See also the receiitlj'-published paper by L. E. Griffin, " Notes on the Anatomy of N(n(tilu.s pomjnlncs," Zoo].

Bull. vol. i. no. 3, pp. 147-161 ; with bibliography.

11*

74 MR. G. C. CKICK ON THE MUSCULAR ATTACHMENT OF THE

Speeton Clay, and the latter an Oxfordian Ammonite, now referred to the genus

Cardioceras. Then it is proposed to descrihe the form and position of the scars and of

the annulus (when seen) in various forms of Ammonoids, ranging from the straight (in

the adult) from Bacidites, through Uamites, Crioceras, Ancyloceras, IlacroscapMtes^

Scaphites, and Tnrril'des to the group of the Ammonites ; then in Clymenia and the

group of the Goniatites.

The A^ery fragmentary character, and consequently imperfect determination, of some

of the specimens must he mentioned; hut, hearing in mind the position of the shell-

muscles in the Ammonoid, viz. on the inner portion of the whorl, it will he at once

evident that the traces of the muscular attachment are more likely to he found in

fragmentary specimens, principally on natural internal casts of the body-chamber.

Muscular Scars.

Tlie muscular scars have been best observed in a fragment of Crioceras qnadratnm *,

n. sp., which I obtained from the Speeton Clay of Yorkshire (PL 17. figs. 10, 11). It

consists merely of the base of the body-chamber, and is about 38 mm. long. The greater

part of the test, which was in a very soft, white, friable condition, has been removed by

a stiff brush, so as to expose the surface of the internal cast of the body-chamber without

scratching it. The section of the whorl is subquadrate, the outer area being somewhat

narrower than the inner ; at the last septum the height of the whorl is 29 mm., and

its greatest thickness 27 mm. On the inner (dorsal) area of the internal cast, and near

the posterior extremity of the body-chamber, there are two oval areas, one on either side

of the median line, the major and transverse diameters of etich being 14 mm. and 11 mm.

respectively. The longer diameter of each is placed transversely, but not quite at right

angles to the median line, the inner end of this diameter being slightly in advance of

the outer extremity. The two impressions ai*e nearly in contact, being only about

05 mm. apart at the inner or anterior end of their respective longer diameters ; their

posterior borders are only slightly in advance of the last septum. Each impression is

very slightly roughened, and consequently distinct from the surrounding and somewhat

polished siu'face of the cast. An incised line forms its boundary on the inner, antei'ior,

md outer sides, being deepest on the anterior side, while its posterior boundary is

marked by a faint, somewhat irregular and imperfectly-defined line. No trace of the

portion of the annulus surroimding the base of the body-chamber, and connecting the

muscular impression on the one side Avith the muscular impression on the other side,

can be seen. In the triangular space between the two impressions, and 3 mm. posterior

to the point where they are nearest together, there is near each incised line a veiy

small, shallow, double pit, each pair of pits being disposed longitudinally ; these doubtless

were connected with the muscular attachment of the animal to its shell.

* This is really a Bean MS. name. Some of the examples of this species in the British Museum Collection bear

this name in Bean's handwriting, and I have adopted tlic name, since, so tar as I know, the species has not j'et

lieen described.

ANIMAL TO ITS .SHELL IN SOME FOSSIL CEPHALOPODA. 75

Animlus.

The impression of the annuius lias been observed in several specimeDS, but in the

British Museum Collection (No. C. 6801) there is an example of Cardioceras excavatimi

(J. Sowerby) * from the Oxford Clay, but the locality is not recorded, in whicli the form

of the miiscular attachment, and particularly that of the annuius, is remarkably well

displayed (PI. 18. fig. 8). The specimen is apparently complete, and shows the aperture

of the shell, which is provided with a narrow, ventral (or peripheral) apophysis. Its

dimensions are : — Diameter of shell 120 mm. ; width of umbilicus 21 mm. ; height of

outer whorl 58 mm. ; ditto above preceding- whorl 40 mm. ; thickness of outer whorl

about 43 mm. The body-chamber occupies the last half of the outer whorl, its base

being 44 mm. high and 29 mm. wide or thick. The whorl is subsagittate in transverse

section ; its inner margin slightly overhangs the umbilicus, so that the width of the

umbilicus, measured at the umbilical margin, is less than that measured at the suture of

the shell. A greater part of the test is preserved, and this is mostly in a soft friable

condition. Some of it had been removed from the left t side of the specimen, so as to

expose a portion of the internal cast of the base of the body-chamber. By means of a

small stiff brush the rest of the test was carefully cleared from both sides of the base of

the body-chamber, and the form of the muscular attachment of the animal was displayed

very clearly, especially on the left side, the attachment on the right side being jjreciselv

similar, but a little less distinct. On the left side the impression of the anterior boundary

of the shell-muscle crosses the umbilical margin 5 mm. in advance of the last septum, and

passes as a very narrow l)and of a. thin film backward and outward in a flat forwardly-

convex curve as far as the middle of the second lateral lobe, at which point, and 1"5 mm.

posterior to it, there is seen to be another similar band Avhich passes from the mnbilicus

immediately above the saddle on the margin of the umbilicus ; these two bands, con-

tinuing at abou.t the same distance apart, pass over the lateral saddle into the first lateral

lobe and, then diverging slightly, pass over the peripheral or external saddle forward and

outward towards the jjeriphery in a flat forwardly-convex curve, but becoming very

indistinct before reaching the periphery. These two very narrow filmy bands appear to

l3e the remains of the anterior and posterior boundaries of the annuius respectively.

Remains of the annuius are visible also on the right side, but much less distinctly ;

they are, however, sufficiently clear to confirm the structures which have been mentioned

as existing on the left side.

Having described the usual form of the muscular scars and of the annuhis, I now

proceed to describe their remains in various forms of Ammonoids, commencino" with the

genus Bactilites and proceeding in the order already indicated {ante, p. 73).

* J. Sowerby, Min. Con. voL ii. p. 5, pL cv. (1815).

t The terms " right " and " left " are used in a strictly morphological sense, the periphery (or siphoual area) of au

Amnionoid being ventral, and the anti])eripheral (or autisiphonal) area dorsal.

76 MR. G. C. CRICK ON THE MUSCULAR ATTACHMENT OF THE

Order of Descriptions.

Page

Baciilifes, Lamarck 77

Samites, Parkinson 79

Crioceras, Leveillo 79

Aiicyloceras, d'Orbigny 80

Macroscaphifes, Meek 81

Scaphites, Parkiuson 81

Turrilites, Lamarck 83

[Metcroccras, d'Orbigny) 84

AMMONPrES 85

AmaltheidtE, Pischer 86

Oxi/)wticeras, Hyatt 85

Amalthens, Montfort 86

Cardioeeras, Neumayr & Uhlig 86

Neumayria, Nikitin 89

Tissotia, Douville 90

Lytoceratid^e, Neumayr, emend. Zittel.

Lytoceras, Suess 91

-Sgocekatid^, Neumayr, emend. Zittel.

Arietites, "Waagen 93

^goceras, Waagen, emend. Zittel 95

Sonninia, Bayle 98

Harpoceratid^, Neumayr, emend. Zittel.

Secticoeeras, Bonarelli 98

(Ecotranstes, Waagen 99

DisticJioceras, Munier-Chalmas 100

Stephanoceratidje, Neumayr, emend. Zittel.

Stephanoceras, Waagen 101

Pei'isphi notes, Waagen 102

Aspidoceratid-E, Zittel.

T?eltoceras, Waagen 102

Aspidoceras, Zittel 103

CoSMOCERATIDiE, Zittel.

I'arkinsonia, Bayle 103

Prionotropip.e, Zittel.

Schlcenbachia, Neumayr 104

Clymenia, Miinster . 105

GONIATITES.

Glyphioceras, Hyatt .... 106

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHjVLOPODA. 77

Baculites, Lamarck.

Baculites ovatus, Say. — An example of this species in the British Museum

(No. C. 5415 f/) from the Fox Hill beds (Upper Cretaceous) of Horse-head Creek, South

Dakota, U.S.A., displays the impression of the shell-muscles very clearly. The specimen

consists of the natural cast of nearly the whole of the body-chamber, the cast of the

last locvilus and of a portion of the penultimate loculus. The test has been almost

entii'ely removed from the posterior part of the body-chamber (PI. 17. figs. 1, 2, ifc 3).

The shell in this species is laterally compressed, and tapers very slowly. The length of

the specimen is 290 mm. or abont 11^ inches ; its transverse section is oval, the greatest

thickness being a little nearer the antisiphonal (dorsal) than the siphonal (ventral)

area. Of this length the body-chamber occupies 215 mm., but the aperture is not

preserved. The ventro-dorsal and transverse diameters of the base are 38 and 25'5 mm.

respectively. The two muscular impressions are at the base of the body-chamber and on

the antisij)honal (dorsal) area ; the inner, antei'ior, and outer portions of their botmdaries

can be distinctly traced as a faint, shallow, depressed (not sharply-incised) line. On the

antisiphonal area the suture-line has a small antisiphonal lobe separating the two portions

of a broad saddle, each portion corresponding to the second lateral saddle in an ammonite ;

each of these halves is followed by a rather broad lobe (the second lateral) which separates

it from the saddle occupying nearly the middle of the lateral area, L e. the first lateral

saddle. The median line of the antisiphonal area is occupied by a very shallow longitu-

dinal groove. The inner boundaries of the two muscvilar impressions seem to meet in

the middle line at about 2'5 mm. in advance of the most anterior part of the saddle,

adjoining the antisiphonal lobe. Starting from this point, the boundary of the impression

passes forward and outward until it is S"5 mm. from the same j)art of the suture-line ;

then, turning backward and still maintaining its course outward, it passes along the

outer side of the second lateral lobe, close to the inner side of the first lateral saddle.

The boundary of the other impression has a precisely similar course. The impressions

are somewhat oval, their longer diameters making an angle of about 45 with the median

line of the antisiphonal (or dorsal) area. At a point slightly below the level of

the most anterior part of the adjoining saddle (the first lateral) the outer boundary of

each impi'cssion is a little angular. On one (the right) side of the specimen no trace of

the annulus can be seen, but on the other (the left) side a line is seen to pass from the

angular portion of the impression outward and upw'ard over, and about 1 mm. distant

from, the adjoining saddle ; although it can be traced only for a short distance, owing to

the roughness of the siuface here, it doubtless represents the anterior boundary of a

portion of the annulus.

At a distance of 5 mm. in front of the boundary of the impression on the right side,

there is another line having precisely the same curvature. It is not nearly so distinct as

the one just described, but most probably indicates the anterior boundary of the same

shell-muscle. Possibly the posterior line denotes the position of the shell-muscle diu'ing

the formation of a septum, and therefore dui'ing a period of rest, when the muscle would

78 ME. G. C. CRICK ON THE MUSCULAE ATTACHMENT OF THE

become firmly attached to the shell. The anterior faintly-impressed line may have been

the last attachment of the anterior boundary of the shell-muscle during the gradual

growth of the animal upward prior to the formation of a new septum. The corresponding

line on the left side is obscured by the shelly matter adhering to the cast.

On the median portion of the peripheral area the septum j^ossesses a rather broad

(median) saddle, on either side of which is a small lobe — the two halves of the peripheral

lobe. This is followed by the peripheral or external saddle. Anterior to the septum and on

the central portion of the same area there is a feebly -incised line having the form of half

an ellipse (PL 17. fig. 3) ; it arises close to the outer portion of the external (or peripheral)

saddle, i. e. at about 7 mm. from the median line of the siphonal (ventral) area ; then curves

upward and towards the median line, attaining its greatest height at about 8'5 mm. in front

of the median saddle, or about 5'5 mm. from its commencement. The line seems then to

pass on to the other side without interruption, but the surface of the cast is not sufiici-

ently well preserved to enable this to be stated w4th certainty. Its anterior portion is

about on the same level as the anterior portion of the boundary of the muscular impression.

About 6 mm. in front of this curve there is a similarly-curved feebly-impressed line, w'hich

inost probably is comparable with the faint curve on the opposite (antisiphonal) surface.

Although the annulus is not well shown in this example, there is another specimen

[C. 5415 Jj] in the British Museum, from the same horizon and locality (PI. 17. fig. 4),

which displays the muscular impression less distinctly, but clearly shows the anterior

boundary of a portion of the annulus. This leaves the muscular impression at the " angle "

mentioned in the previous description, and, passing upward over the adjoining saddle

at a distance of about 1*5 mm. from the siiture-line, crosses the next lobe in a shallow

depression, arid again rises over the next saddle iit about the same distance from it as

before. This depression, however, is seen only with difficulty and by turning the specimen

about in a fairly good light. There can, I think, be no doubt that the annulus was in

the form of a simply-w^aved band, being elevated at the saddles and very feebly depressed

in each lobe just as in the example of Cardioceras excavatum already described (p. 75).

The total length of the specimen is 245 mm., the body-chamber (the aperture of which

is not preserved) occupying 165 mm., the diameters of the base of tlie body-chamber

being 44 and 31"5 mm. respectively. The other side of the cast of the body-chamber is

obscured by fragments of the test.

BacHlites vagina , Porbes. — A portion of the muscular impression has also been seen

in an example of this species in the British Museimi Collection [one of the specimens

numbered 83624] from the Upper Cretaceous of Pondicherry, India (PI. 17. fig. 5). It is

merely the internal cast of the greater portion of the body-chamber, about 60 mm. long,

anteriorly incomplete, but fairly perfect posteriorly. Its transverse section is oval, the

diameters of its antei-ior end being 24 and 145 mm. ; those of the posterior end being

19 and 12-5 mm. The antisiphonal surface is broad and slightly flattened, the siphonal

being narrow, flattened, and with suliangular borders. On the broad antisiphonal svu-face

the feebly convex boundaries of the two muscular scars (indicated by a feebly-incised line

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 79

on the internal cast) meet nearly in the middle line in an obtuse backwardly-directed point

whicli is 3*25 mm. in advance of the saddle on either side of the antisiplional lobe, these

two saddles occupying a large portion of the autisiphonal area. From this point each

Ijoundary passes forward and outward for a short distance, then turns backward and

sweeps over on to the lateral area in a broad anterioi'ly-convex curve whicli gradually

disajipears before reaching the last septum ; if continued to the septum it would meet

the large lateral lobe on its antisiphonal side. It would seem tlierefore that, just as in

the Baculites already described, the muscular scar on either side occupied the space

between the central line of tiie autisiphonal area and the antisiphonal side of the large

lateral saddle. There is no trace of the annulus in this example.

Hamites, Parkinson.

Samites viaximus, J. Sowerby *. — In the British Museum Collection (No. C. 6S02) there

is an example of this species, from the Gault of Folkestone, which displays the form of the

muscular scars exceedingly well (PI. 17. figs. 0, 7). It is only a fragment, /. e. one portion

(the larger) of the terminal hook, and consists of the internal cast of the last loculus and

of a portion of the body-chamber ; its length, measured on the pcrij)hery, is about 55 mm.

The whorl is subcircular in section, only slightly compressed, its ventro-dorsal diameter

(excluding the ribs) at the base of the body-chamber being 16 mm., and its transverse

diameter (also excluding tlie riljs) 15 5 mm. Tlie impressions of the muscular scars are

seen on the inner (dorsal) surface of the cast of the base of the body-chamber, one on

either side of the median line and disposed souieAvhat oldiquely, just as in the exara2:>le

of Crioceras quadraium already described in this paper {ante, p. 74). Each scar is

elliptical in outline, and enclosed by a very faintly-incised line ; its longer axis is inclined

to the median line of the dorsal surface of the body-chamber at an angle of about 45°;

its posterior boundary is only about 1"5 mm. anterior to the antisiphonal saddle of the

last septum. Anteriorly the impressions are 1 mm. apart. The longitudinal and trans-

verse diameters of each scar are 12 and 10 mm. respectively. At about the middle of

the outer portion of the boundary there is a slight angularity, which doubtless indicates

the position of the commencement of tlie anterior border of the annulus, but no other

traces of the annulus have been observed. In another example which is figured (PI. 17.

tigs. 8, 9) each muscular scar bears a small roughened patch, and there are indications of

a narrow band connecting the scars.

Crioceiias, Leveille.

Crioceras quadratumf, n. sp. — The muscular impressions in this genus have been

best observed in two examples of Crioceras quadratam from the Speeton Clay, Yorkshire.

One of these has already been described (see p. 74). The other forms part of the British

Museum Collection (No. 89102). It consists of the natural cast of the body-chamber with

* J. Sowerby, Min. Con. vol. i. p. 138, pi. lxii.(1814).

t See footnote, ante, p. 74.

SECOND SERIES. — ZOOLOGY, VOL. VII. 12

so ME. G. C. CEICK ON THE MUSCULAE ATTACHMENT OF THE

only fragments of the test adliering to it. At the base of the body-chamber the whorl

is subquadratein section, its height being 35 mm., and its greatest width 31 mm. (PI. 17.

figs. 12, 13). The imi:)ressions are not so complete as in the example just described. The

anterior margin of each is indicated by a sharply-incised line ; both lines almost meet each

other in the median line of the inner (dorsal) area at about 10 mm. anterior to the summit

of the innermost portion of the saddle on either side of the antisiphonal lobe. Dis-

appearing posteriorly, each passes forward and outward for a length of about 10 mm., when

each is about 5 mm. in advance of its origin ; then, turning abruptly backward, each

gradually disappears at a distance of about 9 mm. from its point of origin and about

14 mm. from the median line. The posterior extremity of each has a tendency to turn

outward, and at a short distance from the extremity the line gives off a very faint branch

wdiich turns inward, but can be traced only for a short distance. Without doubt the

faint line turning inward represents the boundary of the impression of the shell-muscle,

and that continuing in an outward direction indicates the position of the anterior border

of the adjacent portion of the annulus.

Ancyloceeas, d'Orbigny.

Ancyloceras Matheronimmm, d'Orbigny. — In the genus Aucyloccras what is be-

lieved to be the impression of the mviscular attachment of the animal has been best

seen in an example of Ancyloceras Matlieronimmm in the British Museum Collection

(No. 0. 5322). It is a natural internal cast from the Neocomian of Cassis (Bouches-du-

Pi,h6ne), France (PL 17. figs. 14, 15, 16). The coiled part of the septate portion is wanting,

but the rest is fairly well preserved, although much waterworn. The body-chamber,

measured along the centre of the periphery, is 380 mm. long ; the cross section of its base

is oval, the dorsal (or inner) portion being somewhat wider than the ventral (or outer) ;

the veutro-dorsal diameter (or height) of the base is 75 mm., the transverse diameter

{i. e. the thickness) 54 mm. (excluding the tubercles). What I regard as the impressions of

the boundaries of the two muscular scars are seen on the inner or dorsal area. The two

scars are not quite symmetrical, that on the right side extending about 15 mm. further

forwards than that on the left. These boundary-lines are incised, but they are much

coarser than usual. This, however, is probably due to the -waterworn condition of the

specimen, for the septal sutures, instead of being iinely -incised lines as usual, are fairly

deep and wide, and indeed have quite the appearance of having been considerably water-

worn ; and this condition of the septal sutures suppoi'ts the opinion that the lines about to

be described are really the impressions of the boundaries of the muscular scars. That on

the right commences at about 3 mm. to the right of the median line and about 20 mm.

in front of the large saddle adjoining the antisiphonal lobe ; passing forward for about

35 mm. and approaching nearer the median line, it then turns outward, but still

continues forward until at about 50 mm. from the last septum, when it turns still more

outward and then disappears. That on the left appears to arise about 43 mm. in front

of the miost anterior portion of the saddle adjoining the antisiphonal lobe, and about

6 mm. from the boundary on the right side ; passing forward and outward for nearly

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 81

20 mm., it is then at about 58 mm. from the last septum ; then with a broad curve it

turns backward until it is about 40 mm. from its commencement, when it appears to

rapidly die out. Although the impressions of these boundaries may perhaps be more

properly termed grooves, their form and position agree so well with what I have

observed in somewhat similar forms that I think there can be no doubt as to their

nature. I have not been able to observe any trace of the annulus in this example.

Mackoscaphites, Meek.

Ifacroscophites fjigos, J. de C. Sowerby, sp. — In the genus Ilacroscaphites what 1

regard as the anterior boundary of the muscular scar has been observed in an example

of Ilacroscaphites gigas, J. de C. Sowerby, sp., in the British Museum Collection

(No. 32008). The specimen is stated to be from the Lower Greensand of the Isle of Wight,

but its matrix and state of preservation suggest rather the Kentish Rag (Lower Greensand)

in the neighbourhood of Maidstone (PI. 17. figs. 17, 18, 19). It is a much-compressed

internal cast ; the greatest diameter of its sej)tate jjortion is 180 mm. ; the length of its

body-chamber measured along the centre of the periphery and over the coarse ribs is

350 mm., the height of the base of the body-chamber is 68 mm., the thickness (including

the ribs) being reduced by compression to 22'5 mm. On the right side, at about 15 mm.

above the most anterior part of the last septum and 20 mm. irom the inner margin of

the whorl when viewed laterally, a very fine incised line arises and passes thence as a

flat arc forward and towards the inner margin, which it crosses at about 45 mm. in

front of tlie last septum ; it then curves backward and comes to within about 10 mm. of

the septum, w^here it is in the middle line of the compressed and somewhat distorted

dorsal area. From this point another line, making an acute angle with the line just

described, j)asses forward and outw^ard for rather more than 30 mm., when it curves

outward still more and then disappears. These two curved lines we take to be the

anterior boundary of the right and left muscular scars respectively ; no traces of the

annulus have been observed in this example. The material of this natural internal

cast is very coarse, and the specimen is so much crushed that the very faint lines bounding

the muscular scars can only be followed with difficulty ; the boundary is preserved partly

as an incised line and partly as a line of colour.

ScAPHiTES, Parkinson.

Scctphites biuodosus, A. Roemer. — The muscular impression can be traced in an

example of this species contained in the British Museum Collection (No. C. 5182). It is

from the Lower Senonian (Granulaten-Kreide) of Broitzen, near Brunswdck. The specimen

is a fairly well-preserved, but somewhat distorted internal cast. Its greatest length is

43 mm., and the greatest diameter of the septate portion is 26-5 mm. (PI. 17. figs. 20, 21).

At the posterior end of the body-chamber the whorl is 13'5 mm. higli and 10"5 mm. thick

(excluding the tubercles). The whorl is somew'hat crushed obliquely, so that its sloping-

inner area is much more clearly seen on one (the left) side. On this side a feebly-incised

(partly double) line arises almost close to the last septum, and at a distance of 5 mm.

12*

82 MK. G. C. CRICK ON THE MUSCULAR ATTACHMENT OF THE

from the inner edge of tlie Avliorl ; passing fovAvard in a broad, flattened, forwavdly-

convex cui've, it graduall}^ approaches and finally crosses the inner edge of the whorl at

about 7*5 mm. in front of the last septum. Passing on to the dorsal (or concave)

portion of the whorl, it turns backward, and in a rather broad forwardly-convex curve

nearly reaches the centre of this area, where it appears to be joined by the corresponding

impression on the opposite side. The boundary of the impression on the opposite side

is not quite so distinct, and on the sloping inner area of the whorl it appears to be a

little nearer the inner edge of tlie whorl than on the opposite side, but this is doubtless

due in great measure to the oblique crushing to which the specimen has been subjected.

At the base of the body-chamber it is only 2-75 mm. from the inner edge of the whorl;

passing forward it gradually approaches and finally crosses the same at about 7'5 mm.

in advance of the last septum. I'assing thence in a forwardly-convex carve, it joins its

fellow at about the centre of the dorsal surface of the whorl.

The lines here described are probably the boundaries of the muscular scars. I have

not seen any indications of the annulus in this specimen.

ScapJdtes ceqiialis, J. Sowerby. — The muscular attachment of the animal has also been

observed in an example of Scaphites (eqiialis, J. Sowerby, in the British Museum

Collection (larger of the two specimens, No. S9113). The specimen is an exceedingly

well-preserved and almost perfect natural internal cast from the Lower Chalk of Doi'set.

The greatest length of the specimen is 21) mm. ; the greatest diameter of the sejjtate

part (which is at the base of the body-chamber) is 15-5 mm., the whorl here being 9 mm.

high and 11 mm. wide (excluding the tubercles). The mouth-border is well preserved.

The anterior border of the muscular attachment is preserved on the lateral area as a very

faint line arising (on the leit side) almost close to the last septum and at about 1'5 mm.

from the edge of the whorl, and passing forward and towards the edge of the whorl

crosses this edge somewhat obliquely at about G'5 mm. in advance of the last septum.

Fortunately a portion of the body-chamber can be removed so that the course of this

line can be satisfactorily traced. Continuing still forward it passes into a fairly wide

shallow groove 4 mm. in front of the most anterior portion of the septate part of the shell,

the groove being disposed across the floor or concave portion of the body-chamber in a

flat forwardly-convex curve, with a very slight backward depression at the centre of the

area. A similar fine line can be somewhat less distinctly traced on the right side of the

specimen, passing into the same groove on the floor of the body-chamber. About

3 75 mm. posterior to the groove just mentioned there is another similar but narrower

groove. From my examination of other specimens it is not unlikely that this will prove

to be the posterior boundary of the shell-muscles, which seem to have been united on

the concave portion of the body-chamber into a fairly wide band. The shell-muscles

then appear to have been almost confined to the concave area of the body-chamber, only

a narrow portion extending on to the lateral area.

In the British Museum Collection (No. C. GSOO) there is also a fragmentary example of

the same species (PI. 17. fig. 22), from the concave portion of the body-chamber of which

the matrix has been removed as carefully as possible. There is a similar line on the lateral

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 83

area, passing into a shallow groove on tlie concave portion of the body-chamber, but the

part of the latter between the groove and the anterior ini]n"essed line produced by the

ornaments of the septate part of the shell is covered with a thin, yellowish, powdery

layer, quite unlike the rest of the concave portion of the body-cbamber. This in all

probability indicated tlie place of attachment of the shell-muscles.

I bave not observed tlie remains of tbe annulus iji any example of this species that

has come under my notice.

TuKKiLiTES, Lamarck.

Tm'7'ilites tuberculatus, Bosc. — An example of this species in tbe Museum of Practical

Geology (No. 6372) from the Lower Chalk of Cliffe Anstey, Wilts, displays tbe anterior

border of the muscular scars exceedingly Avell (PI. 18. ligs. 1, 2). Tbe specimen is a

natural internal cast of about live Avliorls, the smallest of whicb is somewhat imperfect,

and the rest fairly well preserved. Two of the upper wliorls show that the sipbuucle [si)

is situated at about one-sixth of tbe height of the whorl below the suture of the shell.

Unfortunately the suture-line is not well shown, so that it is not possible to say exactly

where the body-chc^mber commences. Tbe aperture is fairly well preserved. The height

of the last whorl (from the lowest of the three rows of small tubercles to tbe suture of

tbe shell) is about 52 mm. ; the Avidth of the whorl (/. e. the distance across the specimen)

being 1085 mm. Tbe anterior border of the muscubu- attachment is well shown on the

last whorl as a well-marked narrow groove. VicAving the specimen with the aperture away

from you and directed downward, tbe course of this groove may be thus described : —

Commencing somewhat below the centre of the whorl it passes for a very short distance

(about 2 mm.) downward and to the right ; then, turning still more to the right, it passes

for a distance of about 13 mm. with a bold convex curve to within 12-5 mm. of the

lowest row of smaller tubercles ; then turning again still more to the right it glasses

under the uppermost row of small tubercles. Just beneath the tubercle to the left of

the one under which this groove passes there are indications of a septal suture ; this is

believed to be the last septum, and therefore to indicate the commencement of the body-

chamber. Passing still to tbe light and down\Aard in a broad feebly-convex curve, and

at the same time becoming deeper, the groove crosses the two lower rows of small

tubercles at about 30 mm. from the last-mentioned bend ; it is continued on to the

surface below the tubercles until at about 10 mm. below the lowest row it curves round

in a broad curve and passes to the left for a short distance; then at about 21 mm. below

the lowest row of tubercles it makes an angular bend, passes downward and to the left

for a distance of 11 mm., when it curves upward and passes into the umbilicus ; this

upward portion can be traced for about 2'1< mm., when it is obscured by matrix. With

the exception of the 15 mm. first described, probably the whole of this incised line

represents the anterior boundary of the two muscular scars.

Turi'ilites Mantelli, Sharpe. — An imperfect example of this species in the Museum of

Practical Geology (No. 0373), from the Lower Chalk of the Isle of Wight, also shows a

portion of the anterior border of one of the muscular scars (PI. 18. fig. 3), The specimen

84 jNlE. G. C, CETCK ON THE MUSCULAE ATTACHMENT OP THE

consists of the natural cast of only two wliorls. The aperture is not preserved, but a

portion of the last whorl without doubt formed part of the body-chamber. The larger

whorl is 30 mm. high (/. e. from the lowest row of tubercles to the suture of the shell),

and measures 65 mm. from side to side. The anterior border of the muscular impression

occurs as an impressed line very near the anterior end of the specimen. Viewing the

specimen with the large whorl downward, this line commences a little below the middle

of the whorl, and, crossing the uppermost of the three rows of small tubercles, turns

somewhat aln'uptly to the right, becomes more deeply impressed, and Avith a bold

anteriorly-convex curve crosses the other two rows of small tubercles and passes on to

the sloping surface below the tubercles, being intercepted at about 11 mm. below the

lowest row of tubercles by the broken anterior end of the specimen.

Although the impression in this specimen is very incomplete, it serves to confirm the

structure which has just been described in Turriliies tuberculatus.

Subg. Heteroceras, d'Orbigny.

Turrilites (Heteroceras) polyplocus, Roemer. — It is exceedingly interesting to have

been able to recognize any indications of the muscular attachment in this subgenus of

Ttirrilites, since here the shell is coiled in the opposite direction to that of the genus

Turrilites, and hence a corresponding inversion of the muscular attachment was to be

expected. The examj)le of Turrilites {Heteroceras) ^joIijjUocks, Eoemer, in which the

attachment has been seen forms part of the British Museum Collection (No. 461-51) and

is from the Upper Cretaceous rocks of Haldem, Westphalia (PI. 18. fig. 4). The specimen

consists of about one and a half whorls. The aperture is exceedingly well preserved, but

the suture-line is not shown, so that the base of the body-chamber cannot be thereby

recognized. The form of the right side of the attachment is seen in fig. 4. Viewing

the specimen as represented in the figure, the line indicating the anterior boundary of the

muscular attachment is seen as an impressed line to commence on the lateral area of the

whorl just to the riglit of the tubercle, which is above and somewhat to the left of the

aperture ; passing downward it turns to the left immediately under the tubercle, and

continues to pass downward for rather more than 20 mm. ; having turned upward

very slightly, it continues as a line of colour in a broad sweep, nearly parallel to the

outer curve of the whorl, to within about 60 mm. of the border of the aperture, when it

again becomes a finely-incised line ; then, turning upward and still passing forward for

about another 20 mm., it curves somewhat abruptly backward, continuing for about

20 mm. ; this last portion of the line enclosing an oval area, open posteriorly, the

diameters of which are 20 and 12 mm. respectively. This area I regard as one of

the muscular scars, and the line leading up to it as being partly the boundary of tlie

shell-muscle, and partly the boundary of the annulus. It is much to be regretted that

in developing the specimen its surface was somewhat scratched and rubbed, so that it

is not possible satisfactorily to foUow the course of the impression on the other side of

the whorl.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 85

AMMONITES *.

Amaltheid ,e, p. Fischer.

OXYNOTICERAS, A. Hyatt.

Oxynoticeras^ sp. — The example (PL 18. figs. 5, 6) apparently referable to this genus,

in Tivhich the form of the muscular attachment has heen observed, is from the Great

Oolite (Stonesfield Slate) of Stonesfield, Oxfordshire, and forms part of the British

Museum Collection (No. 36710). It has been labelled "Ammonites discus, .7. Sowerby,"

but it is jjrobably not referable to Sowerby's species f , although its state of preservation

does not allow an accurate determination. It is a crushed, poorly-preserved, internal cast

lying loose on a piece of matrix. The greater part of the specimen is septate ; the body-

chamber has been broken across obliquely, but fortunately the posterior portion is

preserved. When complete the specimen probably was quite 145 mm. in diameter, and

its umbilicus about 22 mm. wide. The last half-whorl at least was occuj)ied by the

body-chamber, the base of which is o2"5 mm. high and about 10 mm. thick. The

anterior border of the muscular scar and of the anuulus can be traced across each side of

the specimen, but it is more distinct on that side (flg. 5) lying upon the matrix. Here the

anterior border arises from the suture of the shell at a distance of 115 mm. in advance

of the last septum ; after passing forward and outward for a short distance it turns

backward in a rather broad curve, and passes uninterruj)tedly across the body-chamber

in a i'airly straight line, which is almost parallel to the general direction of the last

septum, being in advance of the septum 15'5 mm. on the inner portion of the lateral

area and 21 mm. near the periphery, where it seems to turn backward a little, but this

appeai'ance may be due to the much-compressed state of the fossil ; it has no depressions

corresponding to the lobes of the suture-line. The portion of the border to a distance of

about 13 mm. from the inner edge of the whorl is indicated by a well-marked depressed

line, and the rest of the border is indicated by the anterior boundary of a band of colour

about 4-5 mm. wide, the posterior boimdary of which is not sharply defined. The inner

portion, bounded anteriorly by the depressed line, doubtless rejn-esents the muscular scar,

and the broad band of colour the anuulus ; the scar exhibits distinct lines of growth.

On the opposite side the muscular scar and annulus are less clearly defined. The

muscular impression appears to be somewhat nearer the last septum, for its anterior

boundary arises as a faintly-incised line at a point only S'5 mm. in advance of the last

septum, and passes outward and backward as far as the septum, wliich it meets at a

distance of 8'5 mm. from the inner edge of the whorl. Before reaching the septum,

i. e. at a distance of 3-5 mm. from the septum, this boundary gives off a branch (indicated

by a line of colour) which can be traced as a slightly- waved line across the body-chamber

to the periphery, where it meets the anterior boundary on the opposite side. The

portion of the annulus adjoining the muscular impression ou this side is only about

* The nomenclature and grouping of the Ammonites here adopted are those given by Prof. Dr. K. A. v. Zittel in

his ' Grundzuge der Palaontologie," 1895.

t J. Sowerby, ilin. Con. vol. i. p. 37, pi. xii. (1813).

86 MR. G. C. CRICK ON THE MUSCULAR ATTACHMENT OP THE

1'5 mm. wide for a lengtli of about 8'5 mm. ; it then expands somewhat rapidly to a

width of 4'5 mm., a width which it maintains across the rest of the body-chamber,

joiniog the band on the opposite side, the portion near tlie periphery being, however,

somewhat less distinct than the rest.

The discrepancy in the position of the two impressions is doubtless due in a great

measure, if not entirely, to the crushing which the specimen has undergone during

fossilization.

Amaltheus, Montfort.

Amaltheus spinatus, Bruguiere, sp. — The muscular impression has been observed in

an example of this species in the British Museum Collection (No. C. ''919), the locality of

which is not recorded. The specimen consists of the well-preserved septate portion of the

shell, together with a natural cast of one side of the dorsal (or inuer) part of the posterior

portion of the body- chamber (PI. 18. fig. 7). The dimensions of the sjieciraenat the base

of the body-chamber are : — diameter of the shell 57 mm. ; width of umbilicus 24 mm. ;

height of outer whorl 19 mm. ; ditto above preceding whorl about 17 mm. ; thickness of

outer whorl (excluding ribs) 19 mm. ; ditto (including ribs) 22 mm. A portion only of

the anterior boundary of the muscular impression is preserved. Tliis, Avhich appears as

an impressed line, arises almost close to the suture (of the shell) 9 mm. in front of the

anterior part of the small saddle belonging to the last suture-line that is situated on

the edge of the umbilicus ; it curves outward and backward for a distance of about 5 mm.

where it is about 4 mm. from the suture (of the shell) ; then, passing backward nearly

parallel to the inner edge of the whoid, it appears to divide just before meeting this

small saddle, one part passing on the inner (dorsal) side of the small saddle situated on

the edge of the umbilicus and then disappearing, the other passing on the outer side of

the same saddle and then also disappearing. Posterior to this distinctly-impressed line

there are several very faint lines coacenti'ic with it.

Cardioceras, Neumayr & Uhlig.

Cardioceras excavatum, J. Sowerby, sp. — In the description of the annulus, which

has already been given, I have described the muscular attachment in an example of

this species (see ante, p. 75).

Another example of this species is also figured which shows the course of the anterior

l)0imdary of the muscular scar on the dorsal or impressed portion of the whorl (Pi. 19.

figs. 1, 2).

Cardioceras aff. excacato, J. Sowerby, sp. — The muscular impression is also shown in

an example of Canlioccras in tlie Britisli Museum Collection (No. 50098), but its

locality is not recorded (PI. 18. figs. 9, 10). It is, however, allied to Card, excavatum,

but is more comjiressed and more widely umbilicated than that species. The dimensions

of the specimen are : — diameter of shell 54 mm. ; width of umbilicus 18'5 mm. ; height

of outer whorl 20 mm. : thickness of outer whorl 12 mm. The test has been removed

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 87

from tl)e greater part of the body -chamber, and the latter can fortunately be removed

from the rest of the specimen. The whorl is carinate, subquadrangular in transverse

section, its sides mnch flattened and nearly jiarallel to each other ; at the base of the

body-chamber it is 13'5 mm. high and 10 mm. thick. On the left side of the specimen

(PI. 18. fig. 9), near the base of the body-chamber a feebly-impressed (on the internal

cast) line arises from the suture of the sliell [i. e. the inner edge of the whorl) 4'5 mm. iu

front of the last septum ; it extends outward and backward almost as far as the septum,

nearly reaching the same at the inner side of the second (or inferior) lateral lobe ; it then

turns outward, as if to pass over the adjoining saddle, and soon disappears. When the

body-chamber is detached (PL 18. fig. 10) this incised line is seen to be continued on to

the impressed zone, being also indicated by a difference of colour, the portion posterior

to the boundary being much lighter than the rest of this surface. Prom the edge of the

Avhorl this boundary passes a little backward in an /"-shaped curve nearly to the central

line of the im2:)ressed area, when, turning abruptly backward, it passes nearly parallel

to the median line of this area as far as the small saddle adjoining the antisiphonal lobe.

The corresjjonding line on the other side of the impressed area iias the same form, so far

as it can be traced, but the edge of the whorl on this side is somewhat imperfect. A

line of coloiu" apj)ears to indicate that the median space between the two boundaries was

bridged over anteriorly. Tlie form of the muscular attachment just described on the

impressed area of the outer whorl is confirmed by its appearance on the inner surface

of the dorsal portion of the test of the body-chamber, which remains attached to the

l)receding whoii.

The muscular scar on the right side of the body-chamber is not preserved, the inner

portion of the base of the body-chamber having been broken off.

On the middle of the left lateral area there is a linguiform space, 8 mm. long and

■1 mm. broad, enclosed by a very faint line, open behind and convex anteriorly (PI. 18.

fig. 9). Its lateral boundaries are nearly parallel to the inner and outer margins of

the whorl respectively, the inner being l-'o mm. distant from the inner margin, and the

oiiter at the same distance from the periphery of the whorl. The inner boundary passes

just into the inferior lateral lobe along its outer side, and the outer boundary just passes

into the superior lateral lobe along its inner side. There is a similar linguiform area on

the middle of the right side of the body-chamber, 95 mm. long and 6 mm. wide, oj)en

behind, and Avith a convex anterior boundary. Its inner boundary passes just into the

inferior lateral lobe at its outer side, whilst the outer boundary passes just into the

superior lateral lobe along its outer boundary, and not its inner, as on the opposite side

of the body-chamber. Hence the linguiform area on this side is somewhat broader than

that on the left side, the inner boundary being at about the same distance from the inner

edge of the whorl, while the outer is nearei the periphery than on the opposite side.

Only in this one specimen have these linguiform areas been observed ; but, as they are

so distinctly displayed on both sides of the fossil, it is just possible that they are

connected with the attachment of the animal to its shell. This example seems to support

the figure given by Trautschold.

SECOND SF.KIES. — ZOOLOGY, VOL. VII. 13

88 MR. G. C. CEICK ON THE MUSCULAR ATTACHMENT OF THE

Cardiocerm Sidherlandice, J. cle C. Sowerby, sp. — The position of the anterior

boundary of the sbell-muscle is exceedingly well shown in a large example of this

species from the Oxfordian of Scarborough, Yorkshire. It forms part of the British

Museum Collection (No. 82369). It is a large internal natural cast, about 370 mm. (or

nearly 14f inches) in diameter, the umbilicus being 85 mm. in diameter, and having

almost perpendicular walls. Nearly one-half of the outer whorl is occupied by the body-

chamber, the base of wbich is obtusely cordate in section, 132 mm. (or nearly 5| inches)

high and 210 mm. (or rather more than 8J inches) wide, the inner area being 45 mm.

wide and nearly perpendicular to the plane of symmetry of the shell. The anterior

boundary of the muscular impression, represented by a well-marked groove, crosses the

umbiUcal margin 60 mm. (or about 2| inches) in front of the last septum, and passing

outward and backward becomes much less distinct at about 52 mm. from the last

septum, and at about the same distance from the umbilical margin. It appears,

however, to be continued across the whorl by a faint, somewhat irregular groove, which,

originating some 6 mm. posterior to the groove just described, crosses the whorl in a

flat forwardly-concave curve which is only 15 mm. from the anterior portion of the

lateral saddle, and nearly touches the anterior part of the external saddle ; this we

regard as the anterior boundary of the annulus. Passing inward from the umbilical

margin, the boundary of the shell-muscle is indicated by a distinct groove which

curves somewhat backward, but can be traced onlj'^ about halfway across the inner

area of the whorl.

Cardioceras funifermn, J. Phillips, sp. — A similar boundary of the shell-muscle has

been observed in several examples of this species which are contained in the British.

Museum Collection. It is well shown in an example (No. 50447) from the Oxford Clay"

of Trowbridge, Wiltshire. This is 167 mm. in diameter and 68 mm. thick, the umbilicus

being almost closed and its margin rounded. About one-half of the outer whorl is

occupied by the body-chamber, the base of w^hich is acutely cordate in section, 64 mm.

wide and 72 mm. high. On the left side of the specimen the anterior border of the

shell-muscle is indicated by a groove which crosses the umbilical margin at 9 mm.

anterior to the last septum ; passing backward and outward as a fairly wide groove for

about 10 mm., it then becomes shallower and wider. The posterior boundary of the

muscular scar is represented by a slightly raised ridge, which, passing from the umbilical

margin just above the last septum outward and forward, meets the lower boundary of

the anterior groove at a point 12 mm. from the umbilical margin. The anterior groove

appears to be continued across the whorl {i. e. to within 5 mm. of tiie periphery) as

an exceedingly faint groove, which indicates the position of tlie anterior border of the

annulus ; this is 8 mm. anterior to the lateral saddle, 10 mm. anterior to the external

saddle, and is depressed at each lobe. On the outer haK of the lateral area of the whorl

this boundary is partly indicated by remains of the test.

On the right side of the specimen there are similar indications of the anterior boundary

of the muscular scar, but uo traces of the annulus.

ANJMAL TO ITS SHELL IX SOME FOSSIL CEPHALOPODA, 89

Cardioceras sj). — Indications of the muscular attachment are well displayed in a small

Ammonite from the Upper Jurassic of Kintradwell, Sutherland, which forms part of the

British Museum Collection (No. C. 4389). Although the specimen is fairly well pre-

served, I have not been able satisfactorily to determine the species, but it seems to be

referable to the genus Cardioceras (PI. 19. figs. 3, 4). Its dimensions are as follows : —

diameter of shell 235 mm. ; greatest thickness 8'5 mm. ; width of umbilicvis 7 mm. ;

height of outer whorl 8 mm. The last two-fifths of the outer whorl are occvipied by the

body-chamber ; the test having been removed from the left side and from the periphery

of this portion of the whorl, the internal cast is weU displayed. Unfortunately only a

small portion of the last suture-line can be made out, the rest being obscured by the

test. The portion of the last septum adjacent to the suture of the shell is obscured, but

on the internal cast of the body-chamber, at a short distance anterior to the last septum,

a very fine incised line arises from the suture of the shell, passes inward in an almost

radial direction for about 2'5 mm., then turns I^ackward for about 0-5 mm., and again

resumes its radial direction across the whorl, being feebly depressed as it passes over each

lobe, and slightly raised in passing over each saddle; it is about 0"5 mm. above the

lateral saddle and almost touches the most anterior portion of the external saddle. As it

approaches the periphery it lu^rns forward to join a somewhat peculiar-shaped roughened

scar represented in fig. 4, the posterior inflated portion of which is rather rougher than

the rest. Unfortunately the opposite side is obscured by matrix. The perijihery of the

posterior portion of the body-chamber seems to be somewhat deformed, and to possess a

feeble keel with a shallow sulcus on either side ; this deformation may account for the

median division of this scar, which probably was originally horseshoe-shaped, as observed

in several otlier Ammonoids.

The portion of the incised line near the suture of the shell doubtless represents the

position of the anterior border of one of the shell-muscles, the rest of the line indicating

the position of the anterior boundary of the annulus, there having been, in addition, a

firm attachment at the centre of the 2:)eriphery.

Neumaykia, Xikitiu.

Nenmayria catenulata, Fischer, sp. — In the British Museum Collection there is an

example of this species exhibiting the form of the muscular attachment. It is a badly-

cruslied internal cast from the Portlandian of Choroschowo, near Moscow, Russia. The

specimen is 119 mm. in diameter, the width of the umbilicus (from suture to suture) being

18 mm., the height of the outer whorl 58 mm., and its thickness 26 mm. The inner area

of the whorl slopes towards the umbilicus and at the base of the body-chamber is 6 mm.

wide, the height of the whorl here being 43"5 mm., and its greatest thickness, which is at

a short distance from the umbilical margin, 15-5 mm. Tlie last two-thirds of the outer

whorl are occupied by the body-chamber. The whorl is sagittate in cross section. The

muscular impression is well shown on one side, but tlie crushed condition of the specimen

has obliterated it on the other side. Arising from the suture at about 7 mm. from the

base of the l)ody-chamber, the boundary of the impression, in the form of a faintly-indented

13*

90 MR. G. C. CRICK 0]S THE MUSCULAR ATTACHMENT OF THE

line, passes outward and backward in a curve, which nearly meets the last septum at

about ll'Onim. from the suture, and thus encloses a subtriangular area on the inner side

of the base of the body-chamber. Just before this outer line reaches the last septum it

gives off a very faint branch which passes outward towards the periphery, but can be

traced for a very short distance only. This is, without doubt, an indication of the anterior

boundary of a portion of the annulus. Within and parallel to the outer boundary of

the impression there are one or two very faintly indented lines.

TissoTiA, Douville.

Tissotia Uwaldi, v. Buch, sj). — The muscular impression is shown iu an example of

this species in the British Museum Collection (No. C. 4810 a) from the Chalk (Senonian)

of Mezab-el-Mesai, Algeria (PI. 18. fig. 11). The specimen is a natural cast, 8S'5 mm. in

diameter ; rather more than one-fourth of the outer whorl is occupied by a portion of the

body-chaml)er, but this latter is somewhat imperfect on one side, so that the dimensions

of the specimen can best be taken at the base of the body-chamber. Here its dimensions

are as follows : — diameter of shell 84'5 mm. ; width of umbilicus 8'5 mm. ; height of outer

whorl 42 mm. ; greatest thickness of same (at a short distance from the umbilicus) 47 mm.

The whorl is obtusely cordate in transverse section, rather wider than high, and indented

to rather more than one-half of its height by the preceding whorl. The anterior border

of the muscular impression is represented by a feebly-incised line. It cannot be traced

quite as far as the suture of the shell, but on the narrow inner area of the whorl it is 4 mm.

from the last septum ; passing thence forward and outward on to the lateral area, it

attains its greatest distance from the last septum (viz. 8"5 mm.) at 4 mm. from the edge

of the whorl. Then, curving backward, it passes on the vimbilical side of, and at a

distance of 1'5 mm. from, the first (counting from the umbilicus) large lateral saddle, and,

turning forward, sweeps round in an anteriorly-concave curve immediately about the

small saddles occupying the margin of the umbilicus and soon disappears. The muscular

scar thus bounded appears to have been an oval about 10 mm. by 7 mm., its longer axis

being placed nearly in a radial direction but slightly inclined backward. Prom the

anterior portion of the boundary of this impression a feebly-depressed line passes

backward and outward in a broad f or wardly- convex curve to within about 2*5 mm. of

the outer portion of the first (counting from the umbilicus) large lateral saddle, then in

a forwardly-concave curve crosses the adjacent lobe, and disappears just above the next

lateral saddle. This line may indicate a portion of the anterior boundary of the

annulus.

The opposite side of the body-chamber has been so much eroded that the muscular

impression is not preserved.

A^'IMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 91

Lytoceratid^, Neumayi", emend. Zittel.

Lytoceras, Suess.

Lijtoceras cornucopia;. Young & Bird, sp. — The impression of one of the slicll-muscles

has been observed in an example of this species in the British Museum (No. 37851) from

the Upper Lias of Whitby, Yorkshire (PI. 19. figs. 15, 16, 17). The dimensions of the

specimen are : — diameter 22 mm. ; width of umbilicus 8 mm. ; height of oviter whorl

8 mm. ; greatest thickness of the outer whorl 8 5 mm. Rather more than one-half of

the last whorl is occupied hj the body-chamber, the base of which is nearly circular, its

dorso-ventral and transverse diameters being each G mm. The amount of indentation by

the preceding whorl is very small. At the base of the body-chamber, and on the inner

area of the whorl, tliere is an oval impression (fig. IG), truncated on the inner side by the

ed-TC of the " impressed zone." The diameters of the portion that can be seen are

1-75 mm. and 2'0 mm. respectively, the longer diameter being placed transversely on

the whorl. The anterior and the posterior boundaries are both visible, the latter l)eing

almost close to the first auxiliary saddle ; but no trace of the annulus can be seen.

On the peripheral area there is an elongated linguiform impression (fig. 17), which is

rounded and submucronate anteriorly, but is open posteriorly, each limb being situated

in each half of the siphonal (periphei'al) lobe. Its anterior portion is a little in advance

of the most anterior part of the siphonal saddle ; its posterior portion is slightly

contracted. Its length is 3'25 mm. and its width (between the limbs) '75 mm.

In the British Museum Collection there is also a portion of the natural internal cast of

the body-chamber of another example of this species (PL 19. figs. 13, 14), from the Upper

Lias of Whitby, which exhibits the impression of the boundary of the right muscular

scar surrounded anteriorly and laterally by a dark-coloured, longitudinally-elongated,

oval area, a portion of which is slightly rougher than tlie rest. Its form is shown in

fig. 13. Only the right side of the base of the body-chamber is preserved, the heiglit of

the whorl here being 35 mm. At about 4'5 mm. anterior to the last septum, the incised

line indicating the position of the boundary of the muscular scar passes fi-om the suture

of the shell — /. e. the edge of the impressed zone — in a radial direction for about 7 mm. ;

then, turning abruptly backward nearly at right angles to its former course, it is

continued as far as the last septum. At the suture of the shell the boundary of the

oval dark-coloured area is 3'5 mm. anterior to the incised line just mentioned ; after

proceeding forward in an anteriorly-concave curve for about 2 mm., it passes in an

anteriorly-convex curve forward and outward for about 7 mm. ; then, after curving

gently backwai'd for about 5 mm., it can be traced nearly as far as the last septum,

having a direction nearly parallel to the edge of the impressed zone.

Lytoceras fimbriahmi, J. Sowerby, sp. — The muscular impression is also shown in a

fragmentary example of this species in the British Museum (No. 20837) from the Middle

Lias of Kilsby Tunnel, Northamptonshire. The specimen consists of nearly half a whorl,

and is a natural cast of part of the body-chamber of a shell having approximately the

92 MK, G. C. CBICK ON THE MUSCULAR ATTACHMENT OF THE

following dimensions : — diameter 120 mm. ; width of umbilicus 49 mm. ; height of

outer whorl 44 mm. ; greatest thickness of ditto 41 mm. The posterior portion of the

body-chamber is preserved ; one side is much crushed, but the rest is fairly comjilete. A

portion of the test still adheres to the cast. The sjjecimen, measured along the median

line of the periphery, is 165 mm. long ; its transverse section is ovate, the greatest

thickness being at about two-fifths of the height of the whorl from the inner edge ; at

its posterior end the height of the whorl and its thickness (allowing for the crushing) are

80 mm. and 27 mm. respectively. The impression of one shell-muscle is well shown,

but only the inner portion of the other (PI. 19. figs. 11, 12). The whorl is very slightly

imj^yressed by the preceding whorl. In shape the impression is truncated-oval, its

longer diameter being transverse and tlie truncated end towards the median line of the

dorsal surface. Arising a little in advance of the saddle on the side of the antisiphonal

lobe, the boundary of the impression passes forward for about 5 mm. nearly parallel to

the median line of the dorsal or antisiphonal surface, and at 1'5 mm. from its fellow on

the opposite side ; then, curving outward, it extends for about 10 mm. ia a direction

almost at right angles to its previous course; bending rather abruptly backward, it

jiasses for a short distance nearly parallel to the boundary of the impressed zone ; tehn,

curving inwai'd and backward, it speedily disappears. The greatest width (transverse)

of the impression is 12 mm. There is no trace of the annulus. The boundary of the

impression is indicated by a depressed line, Avhich is rather deejily incised on the inner

and outer portions, but somewhat less so on the anterior portion. The portion of the

surface of the cast bounded by tlie impression is a little rouglier than the rest. Owing

to the crushed condition of the whorl, only the inner portion of the other impression

is preserved. The impression is so situated that in a lateral aspect of the whorl only a

very small portion of it can be seen (fig. 12).

Lytoceras qiuidrisulcatimi, d'Orbigny, sp. — One example of this species, collected by

Dr. J. W. Gregory in East Africa, exhibits a portion of the muscular impressions. It is

a crushed fragment of a natural cast of the posterior pai"t of the l)ody-chamber. The

inner portion of the whorl is badly crushed, but exhibits on either side a part of the

muscular scar. At the base of the body-chamber the whorl is 30'5 mm. high and

80 mm. thick, the greatest thickness being a little within the central portion of the lateral

area ; tlie transverse section is therefore nearly circular. The muscular scars are somewhat

darker than the surrounding surface of the cast, and present a slightly roughened

appearance. That on the left is the better shown, but its inner portion is obscured so

that the "whole of its anterior border is not visible. Its bovmdary is usually a feebly-

indented line, but sometimes a slightly-raised line. Tiie anterior boundary of this

impression appears to commence at about 7'5 mm. in advance of the most anterior part

of the last septum, and about 8 ram. from the central line of the impressed zone; it

passes thence slightly forward and outw^ard for a distance of about 2 mm. ; then,

curving backward at about 10*5 mm. from the median line, it passes for a short distance

nearly parallel to the median line ; then, at about 4'5 mm. in advance of the last septum,

ANIMAL TO ITS SHELL IX SOME FOSSIL CEPHALOPODA. 93

curving rather abruptly inward but still passing backward, it disappears at about 5'5 mm.

from the median line, exlni)iting, however, a tendency to again turn forward. The

portion of the scar which is visible has a pyrifortn shape ; its axis is at an angle of

about 45° with the median line of the dorsal area of the whorl, the '"stalk" being-

directed outward and backward ; its length is about 8'5 mm., and its gi'catest width

about 5 mm.

The other scar is truncated by a fracture crossing it obliquely, so that only the

posterior portion of the impression is seen. It is somewhat darker than the surrounding

surface, and bounded anteriorly and laterally by a very slightly-raised line. Commencing

from the fracture at about 9 mm. in advance of the most anterior part of the last septum,

and at the same distance from the median line of the dorsal area, the anterior boundary

passes backward and very slightly outward ; then, curving round, comes to within 2 mm.

of the suture-line ; then, curving inward and forward, it is again intercepted by the

fracture at about 4 mm. from the median line. The anterior and outer boundaries of

the impression are sharply marked by a feebly-incised line, but the posterior boundary is

not quite so sharply defined.

There is a very shallow and rather broad depression on the peripheral area about 5 mm.

in front of the summit of the siphonal (peripheral) saddle ; on either side of the median

line of the periphery, and at a distance of 3 mm. apart, a very faint line curves forwai'd

and towards the median line of the periphery, nearly meeting its fellow at about 3 mm.

anterior to the depression just mentioned. This possibly represents the anterior border

of the peripheral portion of the annulus.

JiIgoceratid.'E, Neumayr, emend. Zittel.

Arietites, Waagen, emend. Zittel.

Arietites ohtusus, J. Sowerby, sp.* — The muscular impression is well shown in an

example of this species from the Lower Lias of Lyme Regis, that was kindly lent to me

by Mr. G. F. Harris, F.G.S. The specimen is a fairly-complete internal cast, almost

entirely denuded of the test. Its dimensions are : — diameter of shell 101 mm. ; width

of umbilicus 43 mm. ; height of outer whorl 32 mm. ; ditto above preceding whorl

29 mm. ; greatest thickness (excluding ribs) 30 mm. ; ditto (including ribs) 33 mm.

The dimensions of the base of the body-chamber are : — height of whorl 26 mm. ; thick-

ness (excluding ribs) 22 mm. ; ditto (including ribs) 25 mm. The body-chamber is

complete and occupies the last half-whorl. The muscular impression is situated at the

base of the body-chamber and occupies the inner area of the whorl (PI. 19. figs. 8, 9, 10).

Its anterior boundary, represented by a fine incised line, is convex, its anterior portion

being 16 mm. in front of the anterior portion of the second lateral saddle of the last

septum. Passing backward its outer boundary is nearly parallel to, and at a distance

of 6 mm. from, the suture (of the shell). It can be traced backward for a distance of

* Min. Con. vol. ii. p. 151, pi. clxviii. (l'6\'l)= Asteroceras ohtusum (J. Sowerby): fide Hyatt, 'Genesis Arietidse,'

1889, p. 201.

94 MK. G. C. CRICK ON THE MUSCULAE ATTACHMENT OF THE

11 mm., beyond which point the surface of the cast is fractured. About 2 mm. behind

this line, and nearly concentric with its anterior portion, tliere is another very faint line,

evidently marking a former attachment of the shell-muscle. On the inner area of the

Avliorl there are three or four fine, faint, longitudinal grooves, extending over three-fourths

of the length of the body-chamber; one of these, 2 mm. from the suture (of the shell),

extends the whole length of the body-chamber.

On the periphery, on either side of the median line, there is a feebly-impressed

sigmoidal line (fig. 10), tlie anterior portion of which is about 11 mm. in advance of the

anterior portion of the external (peripheral or siphonal) saddle. Each line arises about

2 mm. from the median line of the periphery ; it passes away from this line, and backward

to about 8 mm. from the most anterior portion of the external (peripheral or siphonal)

saddle, and then disappears. These lines may indicate the position of the attachment of

the animal to this part of its shell, but no connection can be seen between these

lines and the impressions on the inner area. A line drawn from the centre of the

shell to the most anterior part of these lines on the periphery crosses the inner

edge of the outer whorl at a point 7"i3 mm. posterior to the anterior boundary of the

impression which is seen on the inner area.

Posterior to these lines on the peripheral area there is a horseshoe-shaped marking

with nearly parallel sides, each of which passes posteriorly into each half of the sijjhonal

lobe. It is rounded anteriorly, and crossed in its length by several lines parallel to the

anterior border. Its length (above the small median saddle) is 11 mm., and its width

5 mm. This may, or may not, be connected Avith the muscular attachment of the

animal, but similar impi'essions have been observed in other forms. (See jEgoeeras

capi'icorn/iij/, p. 95.)

Arietites rarlcostatus, Zieten, sp.*- — In the British Museum Collection there is an

example of this species (No. 0.4882) showing the muscular impressions (PL 20. figs. 10, 11).

The locality of the specimen is not recorded, but, judging from the matrix, it came pro-

bably from the Lower Lias of Somersetshire. The specimen is a well-preserved natural

cast with the following dimensions : — diameter 51 mm. ; Avidth of umbilicus 33 mm. ;

height of outer Avhorl 10 mm. ; greatest thickness of outer whorl (excluding ribs)

14 mm.; ditto (including ribs) 16 mm. The body-chamber occupies the whole of the

last whorl, and its posterior part {ah) can be removed from the rest of the fossil; its

transverse section is transversely oval, its thickness (excluding the height of the ribs)

being 10 mm., and its height 7 mm.; it was only slightly indented by the broad periphery

of the preceding whorl. The greater part of the muscular impressions is on the concave

dorsal area, i. e. on the impressed zone. On either side of the median line of this area

(fig. 11) there is a subti'iangular impression, having its broadly-rounded apex directed

forward. These impressions are about 1 mm. apart, that on the right side of the shell

being the more nearly complete. Each is bounded by a faint double fine. Commencing

* F. Zieteij, Vcrsteia. Wiirt. p. 18, \>\. siii. f. 4 = Caloceras rarkostatum {Ziitien), Jidi Hyatt, Gen. Arietidae,

p. 144.

ANIMAL TO IT.S SHELL IN SOME FOSSIL CEPHALOPODA. 95

at the most anterior part of the antisiphonal (or antiperipheral) saddle and at a point

0'5 mm. from the median line, the boundary of the more nearly complete impression

2)asses forward and outward until it is 3 mm. in advance of the last septum and about

2 5 mm. distant from tlie median line ; then, turning backward and passing still outward,

it apj)roaches the last sejitum, and nearly (but not quite) meets the inner portion of the

lateral saddle, where it disappears, its place of disappearance being 4*5 mm. from the

median line of the dorsal area or of the impressed zone. The outer boundary of the

muscular impression is on the edge of the umbilicus, and therefore in a lateral view of

the Ammonite only the outer backwardly-directed portion of the impression can be seen.

There is a corresponding and similar impression on the other side of the specimen, but it

is not so complete, owing to a fracture of the fossil. There are no traces of the annulus.

JiIgoceras, Waagen, emend. Zittel.

JEcjoceras cajjricornum, Schlotheim, sp. — A portion of the im2")ression of the muscular

attachment of the animal has been observed in an example of this species from the

Lias of Cheltenham, that forms part of the British Museum Collection (No. 67929).

The specimen is a well-preserved natural cast, bearing portions of the test in a soft, white,

friable condition (PI. 20. fig. 2). By removing this with a stiff In'ush from near the

base of the body-chamlier, the muscular impression is well shown on either side. The

dimensions of the specimen are as follows : — Diameter of shell (including ribs) 47 mm. ;

ditto (excluding ribs) 44 mm. ; width of imibilicus 20 mm. ; height of outer whorl

(including ribs) 15 mm. ; ditto (excluding ribs) 14-5 mm. ; thickness of whorl (including

ribs) 17 mm. ; ditto (excluding ribs) 14-5 mm. At the base of the body-chamber the

height and thickness of the whorl are respectively 11 and 13 mm. including the ribs, or

10 and 10"5 mm. excluding the ribs. The outline of the muscular impression is seen on

either side at the base of the body-chamber and quite close to the suture of the shell.

It is convex anteriorly, its anterior boundary being 6 mm. in front of the most anterior

jwrtion of the second lateral saddle ; its outer boimdary is nearly parallel to, and at a

distance of 2 mm. from, the edge of the impressed zone, and passes jiosteriorly on to

the outermost branch of the second lateral saddle. Its anterior boundary exhibits a

tendency to curve forward at the suture of the shell. In the middle of the jieripheral

area there is a tongue-shaped scar, which is rather more than twice as long as wide,

has nearly parallel sides, and is rounded anteriorly ; each side of it just touches the

boundary of the siphonal lobe. The scar seems to have been covered with a thin film of

shelly matter, for j)art of this has been broken away from the anterior portion so as to

expose a black layer beneath. This scar would be situated in the immediate neighbour-

hood of the siphuncle, and may or may not have had anything to do with the muscular

attachment of the animal. Its length above the extremity of the small median saddle

is about 6 mm., and its width is 1"5 mm. A precisely similar scar has been observed in

Arietites obtiisns*.

* See ante, p. 93.

SECOND SERIES. — ZOOLOGY, VOL. VII. 14

96 ME. G. C. CRICK ON THE MUSCULAE ATTACHMENT OF THE

The outline of the musculav impression is also well shown in another example of this

species from the Lower Lias, near Whitby, in the collection of F. L. Bradley, Esq., F.G.S.,

of Alderley Edge, Cheshire, to whom I am greatly indebted for the loan of the specimen.

The impression has the same form and position as that already described in the example

from the Lias of Cheltenham, which is in the British Museum Collection (No. 67929).

The specimen is in the centre of a nodnlc ; its dimensions, so far as can be ascertained,

are as follows : — diameter of shell 65 mm. ; width of umbilicus 31 mm. ; height of

outer whorl 16 mm. ; ditto at base of body-chamber 13 mm. The last half-whorl is

occupied by the body-chamber, the exposed portion of which is almost completely

denuded of the test ; at its base and on the inner portion of the whorl the outline of the

muscular impression can be seen. The anterior convex boundary of the impression is

5"5 mm. in advance of the last septum, the width of the impression from the suture of

the shell being 2 mm.

There is no trace of the annulus, and the perijiheral portion of the fossil is obscured

by matrix.

JEgoceras laqueolum, Schloenbach, sp.* — In an example of this species from the

Lower Lias of Harbury, Warwickshire, in the British Museum Collection (No. C. 6619),

one of the muscular scars is well displayed. The specimen consists of about three-fourths

of a whorl 165 mm. in diameter, and is a natural cast of part of the body-chamber.

The base of the body-chamber is complete : it is 24 mm. high ; 30 mm. wide including

the ribs, or 29 mm. excluding the ribs. The muscular scar, which is clearly seen at the

base of the chamber, is situated partly on the lateral area and partly on the impressed

zone (PI. 20. figs. 3, 4). The faintly-incised line bounding the scar arises from the last

sejitiim at a point 4"5 mm. from the inner edge of the whorl ; then, passing forward for

a length of about 9 mm. nearly parallel to the inner edge of the whorl, it turns towards

the impressed zone, becomes much more distinct, and crosses the inner edge of the whorl

13 mm. in advance of the last septum ; passing on to the impressed zone with a rather

broad sweep, it gradually disappears, but the form of the scar is indicated by a difference

in colour, the impression being a little darker than the surrounding surface. The

impression did not quite reach the middle of the impressed zone ; it appears to have

been elliptical in form, about 15 mm. long and 11 mm. wide, the larger portion being

situated on the impressed zone. On the anterior portion of that part of the scar which

is situated on the imjjressed zone there is an exceedingly faint line, concentric with the

anterior border of the scar, which evidently marks a former attachment of the anterior

border of the shell-muscle.

Only a very small portion of the other scar is visible ; this is on the impressed zone.

The greater part of the imjn-ession is obscured by matrix.

There is no trace of the annulus.

* raltcontogr. vol. xiii. pi. xxvi. f. \ = CaJoctras Uaskwn (d'Orbigny), _^c?e Hyatt, Geu. Arietida:, p. 139.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 97

JEgoceras Portlocli'd, Wright. — An example of tliis species from the Boulder Clay of

Ireland (exact locality iinkuown) was sent to me hy Dr. A. H. Foord for determination.

It was in a reddish matrix. It is a natural cast of the posterior portion of the body-

chamber, showing not quite the complete suture-line at its base, and bearing only

fragments of the inner portion of the test. The length of the fragment measured on the

periphery is just over 70 mm. ; the whorl is nuich comjjressed, nearly twice as high as

wide ; the transverse section of the whorl is elongate-oval, its gi'eatest thickness being at

about one-third of the width of the latei'al area distant from the suture (of the shell).

The impressed zone on the inner side of the specimen shows that the indentation

by the preceding whorl was very slight, and that the periphery of the jjreceding

whorl was more acutely convex than that of the outer Avhorl. At the base of

the body-chamber the height of the whorl is 33'5 mm., and the greatest thickness

about 18 mm. Any indication of the muscular attachment that may be preserved

on the surface of the impressed zone is obscured by portions of the test, but on

each side of the inner portion of the lateral area of the posterior jioi'tion of the cast

the impression of this attachment is to be seen. Its anterior boundary commences

at a point on the edge of the impressed zone about 14 mm. in advance of the

most anterior portion of the sutiire-line, /. e. the main or inner branch of the siphonal

saddle ; it passes outward and backward for a length of about 5 mm., then for a short

distance runs nearly parallel to, and at about 5 mm. from, the suture. After passing

backward for a distance of nearly 10 mm. from its commencement, the line divides

into two principal portions, one being continued almost parallel to, and only slightly

approaching, the edge of the impressed zone, the other curving towards, and

apparently reaching, the same edge at a distance of 11 mm. from its commencement.

A fractui-e of the specimen prevents the former of the two lines being traced any

further. About 1 mm. anterior to the incised line just described, there is a much fainter

depressed line which, after extending backward for about 5 mm., nearly parallel to the

incised line already described, appears to turn outward towards the periphery, and then

quickly to disappear, vrhile posterior to the line already described, and also parallel to it,

there are two or three much fainter lines. On the other side of the whorl there

are lines corresponding to the principal incised line, and the line about 1 mm. anterior

to it, but these can only be traced backward sonie G mm., owing to the crushed state of

this side of the specimen.

Near the base of the body-chamber, and slightly on the right side of the median line

of the periphery, there is a horseshoe-shaped incised line having its convexity directed

forward. Its anterior portion is 12 mm. in advance of the anterior portion of the outer

branch of the siphonal (or peripheral) saddle. It is about 6 mm. long, 5 mm. wide in

the anterior part, and 3"5 mm. wide in the posterior part. Each limb appears to be

continued backward as far as the posterior end of the specimen, which is at about

the level of the anterior portion of the outer branch of the peripheral (or siphonal)

saddle, as a somewhat irregular, shallow, very faintly-impressed groove or grooves, each

being almost parallel to the central line of the periphery. The posterior termination

14*

98 ]MK. G. C. CRICK ON THE MUSCULAK ATTACHMENT OE THE

of each liinb is rather more deeply impressed than the rest. Within this horseshoe-

shaped im])ressiou, and occupying- the median line, is a very fine incised line, which

extends backward from about 1 mm. posterior to the anterior boundary of the

impression for a distance of about 6'5 mm. Doubtless this horseshoe-shaped impression

had to do with the muscular attachment of the animal to its shell, for it has been

observed in other forms, but the present specimen does not enable us to trace any

connection between this impression and the marks of the muscular attachment seen on

the inner edge of the whorl.

SoNNiNiA, Bayle.

Sonninia sp. — In the British Museum Collection there is an example (No. C. 5188)

of Sonninia sp. from the Inferior Oolite of Yeovil, Somerset, in which the impression of

the shell-muscles can be seen (PI. 20. fig. 12). The test has been removed from the

internal cast of the whole of the body-chamber, and the impression of each shell-muscle

is displayed near the base of the chamber. The specimen has the following dimensions : —

diameter of shell 91 mm. ; width of umbilicus (from suture to suture) 28 mm. ; ditto

(from margin to margin) 37 mm. ; height of outer whorl 36'5 mm. ; greatest thickness

(almost close to the umbilical margin) 24 mm., excluding thickness of test. The body-

chamber occupies one-half of the last whorl ; at its base the whorl, or more correctly the

internal cast of the whorl, is 27 mm. high and 19 mm. thick. The whorl is subquadrate

in section, with nearly jjarallel sides and well-defined inner area, the latter at the base

of the body-chamber being about 6 mm. wide and sloping towards the umbilicus, making

an angle of about 140° with the lateral area. The boundary of the muscular impression

is indicated by an incised line which appears on the inner area of the Avhorl at a point

10"5 mm. anterior to the last seiDtum; it jDasses outward and. backward, just crossing the

subangular umbilical margin, on to the lateral area, being at about 6 mm. distant from

the suture of the shell, and ajipears to almost touch the saddle of the last septum that is

situated on the subangular umbilical margin. On the area enclosed by this incised line,

and concentric with it, there are several very faint lines, similar to those seen in the

impression of the shell -muscles in the recent Nautilus. The surface of the cast anterior

and also exterior to this incised line bears a number of shallow and iiTegular indentations,

which may have had something to do with the muscular attachment, but the incised

line just described appears to have been the impression of the anterior and exterior

boundary of the shell-muscle. A similar line and similar adjacent indentations are

present on the opposite side of the cast, but no indications of the annulus have been

observed in this specimen.

H A R p o c E R A T I D M, Neumayr, emend. Zittel.

Hecticoceras, Bonarelli.

Meclicoceras hcnticnm, Reinecke, sp. — In the British Museum Collection tliere is

an example (No. 22309 a) froiii the Brown Jura e, Dettingen, Wiirtemberg, which

displays the impression of the muscular attachment on both sides of the body-chamber

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 99

(PI. 20. figs. 5, 6, 7). It is a natural cast, and has the following dimensions : — Diameter

of shell 18'5 mm. ; width of umbilicus 7"5 mm. ; height of outer whorl G%j ; greatest

thickness 4 mm. At the base of the body-chamber the whorl is 5 '5 mm. high and

3'5 mm. thick. The shell is somewhat comjjressed, the inclusion very slight, and the

umbilicus wide and shallow. The body-chamber occupies rather more than one-quarter

of the last whorl, its inner (dorsal) edge subtending a chord of 8 mm. on one side and a

little less on the other side. Erom the fractured anterior end of the body-chamber a

double feebly-impressed line passes backward at a distance of 1 mm. from the suture

(tig. 6) ; then, diverging slightly, the two lines cross the whorl in a rather deep forwardly-

concave curve, their greatest distance from each other being rather more than 1 mm.

Approaching each other slightly, but without touching, they curve forward at the

periphery, each forming a submucronate jioint before passing on to the other side. It is

to be noted that these points are not in the median line of the periphery, but slightly

ou one side (fig. 7). The posterior of the two lines crosses the lateral area about 1 mm.

in advance of the anterior portion of the first lateral saddle. Ou the left side of the

anterior end of the body-chamber (fig. 5) the double line just described curves slightly

towards the periphery, but the opposite side, being a little shorter, does not exhibit this

curvature. This double line probiibly represents a j^oi'tion of the anterior boundary of

the shell-muscle, the two lines on the lateral and j^eripheral areas indicating the position

of the anterior and posterior boundaries resijectively of the annulus.

CEcoTiiAUSTEs, Waagen.

CEcotrmistes crenatus, Bruguiere, sp. — Two examples in the British Museum Collection

(No. 8968), from the Oxfordian of Doubs, France, exhibit what appears to be the

muscular im2)ressiou. Both are natural casts.

One (PL 20. fig. 9) of these (No. 8968 b) has the following dimensions (exclusive of the

spines on the periphery) : — diameter 11 mm. : width of umbilicus 3 mm. ; height of

outer whorl 5 ram. ; thickness of ditto 3 mm. At the base of the body-chamber the

height of the whorl is 4 mm., and its thickness 2"5 mm. The septate part of the shell

and the extreme base of the body-chamber are of a reddish-brown colour, while the rest

of the body-chamber is of a much darker shade, a dark and very distinct line marking

the division near the base of the body-chamber. This line appears to be the anterior

border of the muscultir attachment of the animal. It commences from the suture only a

short distance in advance of the last septum, and crosses in a radial direction the inner

half of the lateral area until reaching the lateral saddle where it is 0*75 mm. in advance

of the suture-line ; it then curves slightly backward, making a very shallow curve, uatil

it reaches a point about 1'25 mm. from the median line of the periphery, where it turns

somewhat abruptly forward, and reaches the median line of the periphery, 2*25 mm. \\\

advance of the summit of the outer (or peripheral) saddle, thus forming on the periphery

a subtriangular projection. A precisely similar line is seen on the opposite side of the

cast, but in tliis species there does not apjiear to be any forAvard prolongation near the

100 ME. G. C. CEICK OX THE MUSCULAE ATTACHMENT OE THE

inner area of the whorl such as has been observed in Distichoceras Bcmgieri (see below)

and Hecticoeeras hecticmn (see p. 98).

The other specimen (No. 896S a) has the following- dimensions, exclusive of the

periphei'al spines, which in this example are comparatively small : — diameter of the shell

11 mm. ; width of umbilicus 2 mm. ; height of outer whorl 5-5 mm. ; thickness of ditto

2'5 mm. At the base of the body-chamber the height of the whorl is 4"25 mm.

(exchiding spines), and the thickness 2'5 mm. The state of preservation of this-

specimen is quite similar to that of the one just described ; the dark line near the base

of the body-chamber, which is most prol)ably the anterior boundary of the mxiscular

attachment, is very like that in the previous specimen, but is slightly more waved on

the lateral area. In this example also there does not appear to be any forward

prolongation of the muscular impression on the inner {not impressed) area of the whorl.

The lack of any forward prolongation in this species seems to be confirmed by a

specimen (No. 19536 e) in the British Museum Collection, from the Drift of Braunstou,

Northamptonshire, in which there is au indication of the anterior boundary of the

muscular attachment near the su.ture of the shell, and in this example also it is only a

short distance anterior to the last septum.

Distichoceras, Munier-Chalmas.

Bistichocoras Bangicri, d'Orbigny, sp. — In the British Museum Collection there are

two examples (No. 5140 a, b) of this species which clearly display the form and position

of the muscular attachment of the animal to its .shell. The species occurs in the

Oxfordian, but the locality of these specimens is not recorded.

In the larger example (No. C. 5140 a) rather more than one-half of the last whorl is

occupied by the body-chamber (PI. 20. fig. 8). Its dimensions (not including the spines

on the edges of the periphery) are : — diameter 17 mm. ; width of umbilicus 4'5 mm. ;

height of outer whorl 8 mm. ; greatest thickness (which is at a very short distance from

the umbilicus) 4*5 mm. At the base of the body-chamber the height of the whorl is

5 mm., and its thickness 3"5 mm., the transverse section being sublanceolatc. Measured

along the curve of the inner portion of the lateral area, the anterior boundary of the

muscular attachment can be seen as much as G'5 mm. in advance of the last septum.

After passing backward at a distance of 1'75 mm. from, and parallel to, the inner edge of

the whorl for a distance of about 5 mm., the boundary then passes outwards in a shallow

curve towards the pcrijihery, just before reaching which it turns slightly forward. There

does not appear to be a definite line at the anterior extremity of the forward prolonga-

tion of the impression, but the area included between the boundary of the muscular

attachment and the inner edge of the whorl is a little roughened, the surface of the

specimen outside this line being smooth and polished. Where the boundary turns

outward there are several fine incised concentric lines. It is to be observed that the

boundary of the forward prolongation of the muscular attachment does not coincide Avith

the longitudinal groove running along the middle of the lateral area, but is situated

between the inner margin of the whorl and this groove.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 101

The smaller example (No. C. 51iO h), wliich exliibits the muscular attachment, has the

following dimensions (excluding both the height of the peripheral spines and the

inflated terminal portion of the body-chamber) : — diameter 15 mm. ; width of umbilicus

4 mm. ; height of outer whorl 6'5 ; thickness 1 mm., the whorl at the base of the body-

chamber being 4'5 mm. high and 3 mm. thick. In this specimen the outer boundary of

the forward ijrolongation of the muscular attachment is slightly more distinct than in

the example already described, and appears to be continued backward as a dark (not

incised) line into the second lateral lobe on one side of the specimen and on to the second

lateral saddle on the opposite side, but txt about 2'5 mm. from the last septum it gives

off a branch which curves outward towards the peripheiy, where it is bent slightly

forward. The width of the forward prolongation of the impression is 1"5 mm., the most

anterior part of the impression being 5 mm. from the last suture-line.

The form and position of the muscular attachment in this species are also exhibited

by a specimen * (No. 22267) in the British Museum from the Brown Jura ^, Beuren,

Wiirtemberg ; it agrees with that already described in the example C. 5110 a.

In this species, then, the shell-muscle seems to have been attached to the long flattened

siu'face on the inner area of the body-chamber. The anterior border of the shell-muscle

and of the annulus agrees almost precisely wdtli that described and figured by Oppel in

his well-known figures of Ammonites \z:=^Oppelia\ steraspis from the Lithographic Stone

of Solenhofen, Bavaria, a fact which supports Prof. Zittel's arrangement of the genera

Distlchocerus and Oppella in the same subfamily [OppdirKc).

S T E p H A N o c E R A T I D ^, Ncuuiayr, emend. Zittel.

Stephanoceras, Waagen.

8tep}ianoceras BanJcsii, J. Sowerby, sp. — There are indications of the muscular attach-

ment of the animal in Sowerby's type-specimen, which forms part of the British Museum

Collection. It is a natural internal cast from the Inferior Oolite of the West of England,

but the 2^recise locality is not recorded. Its diameter is about 230 mm. (about 9 inches)

and its thickness about 150 mm. (or nearly six inches). One-third of the outer whorl is

occupied by the body-chamber, the base of which is 50 mm. high and 130 mm. mde.

The inner area of the whorl is convex and slopes considerably towards the umbilicus.

On the inner area, and arising from the suture of the shell at a point 43 mm. in advance

of the last sejjtum, there is a faint impressed line which jiasses backward and outward

across the inner area, crossing the umbilical mai'gin at about 30 mm. posterior to its

point of origin and 25 mm. from the suture of the shell. Arising from the suture of the

shell, and at a point 20 mm. posterior to the line cxlready described, there is another groove

which is rather more distinct and passes backward (more quickly than the anterior line)

and outward for rather more than 10 mm., then, with a forwardly-concave curve, passes

* A peculiaritj- about this specimcu is that the chambers are arranged as it were in pairs, a large loculus being

succeeded by a small loculus. This is certainly the case with the last sixteen chambers.

102 ME. G. C. CEICK ON THE MUSCULAE ATTACHMENT OF THE

to about the middle of tlie inner area, and then turning backward again it disappears in

the broken surface of the specimen. The anterior line probably indicates the position of

the anterior boundary of the shell-miiscle, and the posterior line possibly the posterior

l)0undary of the same ; I think the latter cannot indicate the position of a former

attachment of the anterior boundary, for it is not parallel to the anterior line. The other

side of the specimen is too badly preserved to show the muscular impression. I have

not observed any indications of the position of the annulus iu this specimen.

Perisphikctes, Waagen.

Ferisphinctea Achilles, d'Orbigny, sp. — The lateral aspect of the muscular impression in

this sj)ecies is clearly shown in an example in the British Miiseum Collection (the smaller

of the two specimens. No. 37017) from the "White Jura of Randen, near Schalfhausen

(PI. 19, fig. 5). The example is a natural internal c;xst, almost completely denuded of

the test. Its dimensions are : — diameter of shell 69 mm. ; width of umbilicus 28 mm. ;

lieight of outer whorl 24*5 mm. ; greatest thickness (almost close to the umbilicus)

16 mm. The whorl is much compressed, and not much indented by the preceding whorl ;

the body-chamber, measured along the median line of the periphery, is about 80 mm.

long. The incised line marking the boundary of the muscular iuipression is j)lainly

visible at the base of the body-chamber. At the inner edge of the whorl it is 5 '5 mm.

in advance of the most anterior part of the last septum ; passing backward and out-

ward for a short distance, it is then continued backward as an exceedingly faint line as

far as the last septum in a direction nearly parallel to the inner edge of the whorl. The

width of the im^u'cssion from the suture of the shell is 2'25 mm., of which only about

one-half is visible in the lateral aspect of tiic shell. The boundary of the anterior

portion of the scar is more deeply incised than the rest.

The impression on the other side is similar, l)ut not qviite so distinct.

There is no trace of the annulus.

AsPIDOCEKATID^, Zittel.

Peltoceras, Waagen.

Peltoceras sp. — The impression of both shell-muscles is well seen on an example of

Peltoceras sp. that was found in the Ampthill Clay at Ampthill Tunnel, and that formed

part of my late father's collection (PL 20. fig. 1). The specimen, a mere fragment of the

natural cast of a large shell, consists of the posterior part of the body-chamber ; it is

about 150 mm. long. It is quadrangular in transverse section, and at the base of the body-

chamber is 73 mm. high, 65 mm. thick (excludiug the ribs), and 72 mm. thick (including

the ribs). An antiperipheral, autisiphoual, or dorsal aspect of the fragment disjilays two

longitudinally-elongated oval scars, somewhat pointed anteriorly and bounded by a faintly

impressed line. The outer boundary of each area terminates ioimediately above the inner

branch of the lateral saddle, while the inner boundary passes down close to the outer side

of the antij^eripheral (or autisiphoual) saddle on the same side. The anterior extremity

ANIMAL TO ITS SHELL IN SOME EOSSIL CEPHALOPODA. 103

of each impression is situated on the edge of the impressed zone, so that about one-

third of the width of the impression is on the impressed zone, the other two-thirds

being on the inner area of the whorl. The two impressions are nearest together at about

half their length ; they are here 19 mm. apart, while the posterior extremities of their

inner boundaries are 32 mm. apart. The length of each impression (measured from the

anterior extremity of the inner branch of the lateral saddle) is about 50 mm. ; the

greatest width being 17 mm. No traces of the annulus have been observed in this

specimen. In the middle of the peripheral area, and extending a short distance into the

peripheral lobe, there is a broad, faint, longitudinal depression about 25 mm. long and

3'0 mm. wide, slightly wider anteriorly than posteriorly. Possibly this had something

to do ^^'ith the muscular attachment of the animal to its shell. On one side of this there

is a narrower, shorter, and less distinct longitudinal depression.

AsPiDOCERAS, Zittel.

Aspidoceras sp. — Among the si^ecimens which Dr. J. W. Gregory collected from

" below Chamgamwe, opposite Mombasa Island," East Africa, there is a fragment of an

Aspidoceras which displays the muscular impression ; it is merely the natural cast of the

posterior part of the body-chamber, and this is incomplete on one side (PI. 19. iigs. 6, 7).

The section of the base is obtusely cordate, and measures about 43 mm. in width and

34 mm. in height. The impression is seen on the inner area of the whorl as a faintly-

impressed line, which, ai'ising from the edge of the impressed zone (corresponding to the

suture of the shell) at a point about 15 mm. in advance of the base of the body-cliamber,

passes outward, describing a curve slightly convex forward, and when at a distance of

9'5 mm. from the edge of the impressed zone jiasses backward nearly parallel to this

edge for a distance of at least 10 mm. It then seems to divide into several very

faint grooves which are continued backward nearly to the base of the body-chamber.

No indications of the annulus can be seen. Unfortunately the cast is very imperfect

on the opposite side.

C O S M 0 C E R A T I D .E, Zittel.

Parkinsonia, Bayle.

Parkmsonia Parkinsoni, J. Sowerby, sp. — The muscular impressions are well shown in a

Avell-preserved example of this species in the British Museum Collection (No. 9) from the

Inferior Oolite of Bayeux (Calvados), Prance. PuUy two-thirds of the outer whorl are

occupied by the body-chamber ; the test having been removed from the greater part of

this chamber, the internal cast is well displayed. The dimensions of the specimens

are : — diameter of shell 213-5 mm. ; width of umbilicus 58 mm. ; height of outer whorl

49 mm. ; greatest thickness of ditto o2'5 mm. The body-chamber appears to be fairly

complete ; its length measured along the median line of the periphery is 287 mm. ;

and the dimensions of its base are : — height 31'5 ram., greatest thickness (which

is at about one-third of the height of the whorl from the inner edge) 22-5 mm.

The muscular impression on each side can be seen. At the suture of tlie shell the

SECOXD SERIES. — ZOOLOGY, VOL. VII. 15

104 MR. G. C. CRICK ON THE MUSCULAR ATTACHMENT OF THE

anterior border, an incised line, is 9'5 mm. in advance of that portion of the

lateral saddle of the last suture-line which is close to the umbilical margin ; it passes

thence outward and backward nearly parallel t6 the suture and almost as far back as

the last septum, when it appears to turn ovitward and pass over this portion of the

lateral saddle as a feebly-depressed rather than an incised line. This last-mentioned

portion of the boundary may have been produced by the anterior border of the annulus.

The greatest width of the portion of the impression that is visible is 5 mm., and it is

confined to the somewhat sloping inner area of the whorl. Its surface is a little

roughened, and the ira^^ression seems to have occupied the lol)e which is situated on the

inner area of the whorl. An irregular, waved, depressed line passes over the siphonal

lobe on eacli side of the body-chamber, and this most probably indicates the position of

a further jDortion of the anterior border of the annulus.

P R I o N o T R o P I D .E, Zittel.

ScHLCENBACHiA, Neumayr.

Schloenhachia GoodhalU, J. Sowerby, sp. — The remains of the muscular attachment

are exhibited by an example of this species in the British Museum Collection (No. 46491).

The specimen is from the Greensand of Blackdown, Dorset. It consists of a segment of

two adjacent whorls, the outer of \\hich exhibits at about its mid-length the basal

l^ortion of the body-chamber, which on the left side is entirely denuded of the test. The

whorl is carinated, much compressed laterally, and its sides nearly parallel ; at the

base of the body-chamber it is 80 mm. high and 45 mm. wide or thick, the inner area

being concave, sloping towards the umbilicus, and 12 mm. wide. On the left side, on the

internal cast of the body-chamber, the anterior boundary of the muscular scar is seen

as an incised line arising at the suture of the shell at about 30 mm. in advance of the

corresponding portion of the last septum ; passing obliquely backward and outward

across the inner area, it crosses the umbilical margin at about 22 mm. in advance of the

corresponding part of the last septum ; it continues outward and backward for a short

distance, and then divides ; one part joasses backward and outward for a very short

distance and then disapjiears ; the other passes backward nearly parallel to, and at a

distance of 4 mm. from, the umbilical margin, and disappears shortly before reaching the

suture-line of the last septum. The branch which passes outward is probably the com-

mencement of the anterior border of the annulus, the other being the outer boundary of

the muscular scar. Arising from the suture of the shell, 13 mm. posterior to the line

already described, and crossing the inner area nearly parallel to the same line, there is

another very feeble groove, which scarcely crosses the umbilical margin before reaching

the last suture-line. Prom the appearance of the inner surface of the piece of the test

which fits on to this portion of the specimen, it seems most probable that this feeble groove

indicates the position of the posterior boundary of the muscular scar. The opposite

side of the whorl is too imperfect to exhibit any trace of the muscular attachment.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 105

At a point 29 mm. in advance of the small median saddle, the periphery is crossed by

an incised line which on the left side passes inward and backward for about 8 mm.,

tlien passini? backward nearly parallel to, and at a distance of 8 mm., from the median

line of the perijAery until it meets the external saddle. Traces of a precisely similar

line can also be seen on the right side. This I believe to have also been part of tlie

anterior boundary of the annulus.

Clymenia., Miinster.

CUjmeuia imdulata, Miinster. — The muscixlar impression in the genus Clymenia has been

best observed in an example of this species in the British Museum Collection (No. 81826).

It is from the Clymeuien-Kalk (Upper Devonian) of Scbiibelhammer, Bavaria (PI. 20.

figs. 13, 14). This specimen, the outer wdiorl of which is somewhat imperfect, has the

following dimensions : — Diameter of shell 48'5 mm. ; width of umbilicus 20'5 mm. ;

height of outer whorllG mm. ; greatest thickness of ditto 12 mm. Nearly one half of the

outer whorl is occupied by the body-chamber, its length, measured along the periphery,

being 65 mm. ; its anterior portion is flattened for a distance of nearly 20 mm., the width

of the flattened portion being 3 mm. It niay be remarked that in this genus the

siphuncle is on the inner side of the whorl, and is relatively much larger than in the rest

of the Ammonoidea. The internal cast of the posterior part of the body-chamber and

of two or three of the succeeding loculi is denuded of the test. The base of the body-

chamber is 12'5 mm. high and 10 mm. thick, the periphery here being quite rounded.

One side of the basal portion is w^ell-preserved, but tlie other is somewhat imperfect.

On the well-preserved side (fig. 13) a curved feebly-iucised line arises almost close to the

suture of the shell and at a distance of 2 mm. from the last sejitum ; j)assing backward

nearly parallel to the inner half of the lateral portion of the suture-line, it just clears

the most anterior poi'tion of the latter and then passes straight on to the periphery,

being at the centre of the latter about 2 mm. anterior to the last septum. It appears

to cross the periphery without iuterruj)tion, but unfortunately the line here is somewhat

obscured, and it is not impossible that the line here may be bent backward into a

very minute V-shaped sinus.

Another feebly-incised line proceeds from the suture of the shell and passes backward

almost close to the last septum for some distance into the lateral lobe ; then turning

forward it meets the anterior line, already described, at the most anterior point of the

lateral portion of the suture-line. At a short distance from this junction and a little

nearer the periphery, the anterior line gives off a bi-anch which gradually recedes from

it and crosses the periphery about 1 mm. posterior to it. At the central portion of the

periphery this line, like the anterior one, is somewhat obscured, but appears to cross

the periphery without interruption, although it is not impossible that at the middle of

the periphery this line may have had a very small V-shaped bend forward.

It would seem, therefore, that the shell-muscle occupied the space between tlie suture

of the shell and the outer side of the lateral lobe, and that the annulus extended from

15*

106 ME. G. 0. CEICK OX THE MUSCULAR ATTACHMENT OF THE

tlie outer side of the lateral lobe across the perijihery as a narrow band having its

greatest width at the centre of the periphery.

Unfortunately, the opposite side of the body-chamber is not sufficiently well-preserved

to show the muscular impression.

Near the anterior end of the body-chamber the internal cast exhibits a wide and

fairly deep groove, which crosses the lateral area in a curve which is concave forward,

and projects considerably forward near the periphery. The lateral portion of the

sroove is fully 0 mm. wide, but shallow, while the portion near the periphery is 4 mm.

wide and deeper than the rest. The opposite side of the specimen is broken here, and

does not show the groove. This groove, however, seems to have nothing to do with the

muscular attachment of the animal, but is here mentioned for comparison with tlie

groove which has been depicted in some Ammonoids (e. g. Pinacoceras*) as the anterior

bonndarv of the muscle and of the annulus.

GONIATITES.

Gltphioceeas, Hyatt.

Glyphioceras crenistria, J. Phillips, sp. — Among the Goniatites the form of the attach-

ment of the animal to its shell is well seen in an example t of this species from Bolland,

Yorkshire (PL 20. figs. 15, 16). It forms part of the British Museum Collection

(No. C. 5080). It is a Avell-preserved example, having the following dimensions: —

Diameter of shell 43 mm. ; width of umbilicus about 4*5 mm. ; height of outer whorl

21-5 mm.; thickness of ditto 27'5 mm. The body-chamber occupies five-sixths of the

outer whorl, and, being denuded of the test, its internal cast is well displayed. The

muscular attachment is so well preserved that it can be traced from the umbilicus on one

side across the whorl to the umbilicus on the other side. As seen in a lateral aspect

(fio". 15) the muscular scar is almost confined to the inner area of the whorl, and is

depressed (on the internal cast) a little below the sui'rounding surface. The most

anterior portion of its anterior boundary is a little more than 2 mm. in advance of the last

septum. Passing backward and outward, this boundary just crosses the umbilical margin

and reaches to within about 1 mm. of the septum, when, turning abruptly outward, it is

continued as a very fine raised line at this distance from the septum, until passing into

the lateral lobe, when it recedes very slightly from the suture-line. It crosses the lobe

in an obtuse point 3"75 mm. from the point of the lobe, and, then passing up the other

side of the lobe, it gradually approaches the suture-line and, just clearing the pointed

external saddle, passes into the external lobe at about 1 mm. from the septum (fig. 16), at

the same time separating into two very minutely -waved lines; at 5 mm. from the apex

* Dr. E. V. Mojsisovics, ' Das Gebirge um Hallstatt," i. pi. xx. figs. 2 & 3 (^Pinacoceras insectum) ; pi. xx.

figs. 8 & 9 {P. liumilc).

t This is the specimen from which the suture-liue figured in Cat. Eoss. Ceph. British Museum, pt. iii. p. 101,

fig. 76, was drawu.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 107

of the external saddle these lines diverg-e, assume a direction at right angles to the plane

of symmetry of the shell, and cross the external lohe with only a very sliglit V-shaped

depression at the median line of the periphery. jS'early at the centre of the peripliery

there is a small circular pit on the posterior lino. On the opposite side of the lobe,

at about 1 mm. from the suture-line, these lines turn aliruptly forward, approach and

coalesce, the resulting line having the same course as that on the opposite side. At the

umbilical margin this line passes into the boundary of the muscular scar, which also has

the same form as that on the opposite side. At the centre of the periphery and imme-

diately behind the lines already described there is a feebly-depressed double line in the

form of a horse-shoe, each side of which passes quite close to the outer side of each half

of the small median saddle; the enclosed area is about 2 mm. wide. At a short distance

anterior to the raised line already described there is a rather broad shallow groove, which

first makes its appearance in the lateral lobe, becomes more distinct all around the

external saddle, and disappears in the external lobe. Almost in the median line of the

periphery, and slightly in advance of the apex of the external saddle, there is a minute,

shallow, oval depression. A fairly-jirominent " normal line " extends some 7 or 8 mm. in

advance of this depression, whilst the surface of the cast behind this depression and in front

of the anterior boundary of the annulus bears numerous fine longitudinal raised lines.

The depressed surface on the inner area of the whorl I regard as a portion of the

muscular scar, and the faint line proceeding therefrom across the whorl I consider

to be the impression of the annulus. The latter then seems to have been over a portion

of its extent merely a line of attachment, but to have been 1 mm. wide on the

periphery.

In the present specimen the boundary of the muscular scar cannot be traced on to

the inner or dorsal poi'tion ( = impressed area) of the whorl, Init this has lieen partially

observed in another example of the same species in the British Museum Collection (the

larger of the specimens Xo. C. 283). The diameter of the shell is 50 mm., the outer whorl

(at the end of the septate part of the shell) being about one-half of the diameter. The

specimen is entirely septate (PL 20. figs. 17, 18), tlie last septum being the base of the

body-chamber. A portion of the test that formed the floor of the body-chamber still

adheres to the preceding Avhorl, and on this the border of the muscular scar can be traced

for a short distance. In this example the anterior border of the scar j^asses on to the

floor of the body-chamber at about 3"5 mm. in advance of the last sej)tum ; for a short

distance it is nearly parallel to the sejjtum, Imt at about the middle of the lateral saddle

it turns towards the septum and seems to disapjiear ; unfortunately the test here has

been broken away, and only a few fragments of the test remain on the opposite side of

the whorl, so that its direction cannot be definitely traced further. On the floor of the

body-chamber (fig. 18) there is also a strong raised line following the lobes and saddles of

the last septum, and about 1 mm. in front of the same ; near the umbilicus it gradually

approaches and then passes into the angle between the septum and the wall of the

shell. This seems to have been a line of attachment of the body of the animal ; but, so

far as can be made out from this example, it does not ajipear to have been continuous

108 MR. G. C. CRICK ON THE MUSCULAR ATTACHMENT OF THE

with tlie anterior border of tlie muscular scar. It may have been the line of attachment

of the j)osterior 2iortion of the body just prior to the formation of a new septum.

Glypliioceras trimcatum, J. Phillij^s, sp. — An example of this species from the

Carboniferous Limestone of St. Doulagh's, co. Kildare, Ireland, which has been lent me

by Dr. A. H. Poord, T.G.S., also exhibits the anterior boundary of one of the muscular

scars A^ery distinctly (PI. 20. figs. 19). The specimen consists of about five-sixths of a

whorl, the whole constituting- part of the body-chamber, the base of which is fortunately

preserved. Its dimensions are: — diameter 75 mm.; height of outer whorl 36 mm. ; ditto

above jireceding Avhorl 20 mm. ; greatest thickness (which is at about the middle of

the lateral area) 27 mm. ; width of umbilicus 10 mm. On one side of the specimen the

anterior boundary of one of the muscular scars is preserved as an impressed line (on

the internal cast of the body-chamber), which arises from tlie suture of the shell at

about 4 mm. in advance of the last septum and curves gently outward and backward.

It can only be traced for a length of about 6 mm., when it is obscured by the test ;

at about one-half of this lencrth it is 45 mm. from tlie suture of the shell.

Summary.

As in the recent Nautilus, so in the Ammonoids, the shell was external and the

animal was attached to its shell by means of " shell-muscles " and an " annulus."

In the Ammonites and such allied forms as BacuUtes, Samites, &c. the shell-

muscles Avere attached to the dorsal portion of the shell; they frequently either

approximated or met each other in the median line of this region ; when they did not

quite meet they Avere doubtless united by a more or less narrow band corresponding to

the dorsal portion of the annulus in the recent Nautilus.

My observations support the conclusion expressed by Dr. Waagcn that the line

figured by Oppel on the body-chamber of Ammonites steraspis indicated the position

of the anterior boundary of the annulus and of the shell-muscles, the latter being

situated, as he supposed, upon the inner or umbilical portion of the lateral area of the

AA^iorl. It is, howcAer, not a little sti*ange that in the species figured by Oppel the

form of the muscular attachment differs somcAvhat considerably from that in the

majority of the Ammonites which I have examined. It would seem that another

intei'pretation is necessary for the figures Avhich have subsequently been given

purporting to be the remains of the muscular attachment.

In the earlier stages of develoj)ment and in the general form of the shell as well as

in the aperture of certain species, affinities have been recognized betAA^een the Ammonoids

and the Dibrauchiatcs. Prom the foregoing it is clear that the Ammonoid animal

possessed a muscular attachment quite similar to that of the living Nautilus, the only

recent genus of the Tetrabranchiates.

Indications of the muscular attachment of the Ammonoid animal, instead of being

rare, seem to be fairly common. There appears to be some ground for believing that

its form is in j^art due to the shape of the transverse section of the Avhorl and to the

ajN'imal to its shell in some fossil cephalopoda. 109

length of the hody-chamher, hut I venture to helieve that it will prove to ha clue to

other causes, and also affoi'd an important character for the purposes of classification.

Thus, among the forms of muscular attachment descrihcd in the present paper, the

shell-muscles in Distichoceras and Oi^peUa seem to have been relatively much longer

than those of the other forms herein described ; and hence one should expect these two

genera to be closely related. Tliis affinity seems to be supported by their other characters,

for they have been placed in the same subfamily, viz. the Oppelince*.

Not only was the Ammonoid animal, like the Nautilus, at least at some periods,

attached to its shell by means of the lobes and saddles of the posterior portion of the

body (corresponding to those of the edge of the septum of its shell), but it seems from

the foregoing descriptions that it was further provided with an annulus in addition to

shell-muscles as in the recent Naiitilus. It would appear, therefore, as if the provision of

an annulus were an absolute necessity to the animal in addition to the shell-muscles,

and most probably Dr. Waagen's explanation of its occurrence is the correct one, viz.,

that the annulus and shell-muscles served not merely to hold the animal to its shell,

but formed also an air-tight band around it, fastening the mantle to the shell.

In conclusion, I desire to express my obligations to those who have in any way assisted

me in my observations. To Dr. Woodward I am greatly indebted for valuable

suggestions and much kind help, while to Mr. B. B. Woodward I am especially

indebted for the advice which he has ever been most willing to give me. My thanks

are also due to my colleague Mr. Edgar A. Smith for giving me every facility in the

examination of the recent Cephalopoda under his charge. For the loan of specimens

I have to thank Mr. F. L. Bradley, Mr. G. P. Harris, and the authorities of the

Jermyn Street Museum. To Messrs. Sharman, Newton, and Allen, of that Museum,

I am under deep obligations for all their kind help during the examination of the

specimens under their charge. To Professor Howes, whose interest in my work has

been a source of great encouragement to me, I desire to present my cordial thanks.

EXPLANATION OF THE PLATES.

The figures are of the natural size unless otherwise stated.

X indicates tlie last septum.

— * marks the remains of the muscular attachment.

Plate 17.

Baculites ovatus, Say (p. 77).

Fig. 1. Dorsal aspect of fragment of body-chamber, showing anterior boundaries of muscular scars.

2. Right lateral aspect of same, showing on the left the boundary of the right muscular scar, and

on the right the incised line on the ventral area.

See Prof. Dr. K. A. v. Zittel, ' Grundziige der Palaoutologie,' p. 420.

110 ME. G. C. CEICK ON THE MUSCULAE ATTACHMENT OF THE

Fig. 3. Ventral aspect of same, showing incised line on median portion.

4. Right lateral aspect of fragment of another example, showing anterior bonndary of right

muscular scar and of a portion of the anuulus.

Baculites vagina, Forbes (p. 78) .

Fig. 5. Dorsal aspect of portion of body-chamber, showing near the base the anterior boundary of the

two muscular scars.

Hamites maxinms, J. Sowerby (p. 79).

Fig. 6. Dorsal aspect of body-chamber, showing the two muscular scars near the base.

7. Left lateral aspect of the same.

8. Dorsal aspect of another example.

9. A portion of the same enlarged, showing the two scars, each bearing near its anterior border

a small roughened patch, and also traces of a narrow band connecting the scars. X '{.

Cr'wceras quadratum, n. sp. (pp. 74 & 79).

Fig. 10. Dorsal aspect of a fragment of the body-chamber, exhibiting the two scars.

11. Left lateral aspect of the same.

12. Dorsal aspect of a frajjment of another example in which the anterior boundaries of the two

scars nearly meet in the median line.

13. Left lateral aspect of the same.

Ancyloceras Matheron'ianmii, d'Orbigny (p. 80).

Fio-. 14. Left lateral aspect, showing portion of anterior boundary of left muscular scar, x \.

15. Right lateral aspect of a portion of the same, exhibiting the termination of the anterior

boundary of the right muscular scar. X 5.

If). Dorsal aspect of a portion of the same, showing the anterior boundaries of the two muscular

scars, that on the riglit being much higher than that on the left. X \.

Macroscaphites giyas, J. de C. Sowerby, sp. (p. 81).

Fig. 17. Riglit lateral aspect. x\.

18. Left lateral aspect of a portion of the same, showing part of the boundary of the two

scars. X 5.

19. Dorsal aspect of a portion of the same, also showing the anterior boundary of the two

scars. X 5.

Scaphites binodusiis, A. Roemer (p. 81).

Fig. 20. Left lateral aspect.

21. Dorsal aspect of a portion of the same, with part of the body-chamber removed.

Scaphites aqualis, J. Sowerby (p. 82).

Fi"'. 22. Dorsal aspect of a fragment of the body-chamber. The curved lines at the lower part of tlie

figure are the impressions of the ornaments of the septate part of the shell ; the anterior

border of the muscular attachment is indicated by the arrow.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. Ill

Plate 18.

TurrUites tuberculatus, Bosc (p. 83).

Fig. 1. Lateral aspect, two of the upper wliorls exhibiting the siphuncle {si), and tlic body-cliamber

showing the muscular attachment, x ^.

2. Dorsal aspect of body-chamber of same, showing the muscular attachment. X \.

TurrUites Mantelli, Sharpe (p. 83).

Fig. 3. Lateral aspect of fragment, the lower whorl of which exhibits a portion of the boundary of the

muscular attachment. x |.

TurrUites {Heteroceras) polyplocus, Roemer (p. 84) .

Fig. 4. Lateral aspect of terminal portion. X |.

Oxynoticeras ? sp. (p. 85) .

Fig. 5. Left lateral aspect of part of an example showing the muscular scar and the annulus. x 5.

0. Right lateral aspect of same, x f .

Amaltheus spinatus, Bruguiere, sp. (p. 86).

Fig. 7. Left lateral aspect of imperfect specimen, exhibiting on the inner portion of the whorl (opposite

the arrow) the boundary of the muscular scar.

Cardioceras excavutum, J. Sowerby, sp. (pp. 75 & 86).

Fig. 8. Left lateral aspect, showing the muscular scar and the annulus. x h.

Cardioceras aff. excavuto, J. Sowerby, sp. (p. 80).

Fig. 9. Left lateral aspect, exhibiting the ar.tcrior boundary of the muscular scar on the inner portion

of the whorl opposite the aiTow, and a linguiform impression on the middle of the lateral

area.

10. Dorsal aspect of posterior portion of the body-chamber of the same, showing near the base the

course of the anterior boundary of the muscular scar on the dorsal area of the whorl.

Tissotia EwahU, v. Buch, sp. (p. 90).

Fig. 11. Left lateral aspect, showing close to the umbilicus (opposite the arrow) one of the muscular

scars, and, passing from it towaids the peripheiy, a portion of the anterior boundary of

the annulus. x f .

Plate 19.

Cardioceras excaratnm, J. Sowerby, sp. (p. 86).

Fig. ] . Right lateral aspect, x §.

2. Sagittal section of the natural internal cast of the body-chamber of the same specimen, showing

anterior boundary of muscular scar on dorsal portion of whorl. X f .

Cardioceras sp. (p. 89).

Fig. 3. Left lateral aspect, showing anterior boundary of scar and of annulus. x 'j.

4. Ventral view of the same, exhibiting the impression on the central portion of that area.

SECOND SERIES — ZOOLOGY. VOL. YII. 10

112 MR. G. C. CRICK ON THE MUSCULAR ATTACHMENT OF THE

Perisphinctes Achilles, d'Orbigny, sp. (p. 102).

Fig. 5. Left lateral aspect. The boundary of the muscular scar is seen on the inner portion of the

outer whorl opposite the small arrow.

Aspidoceras .«/*. (p. 103).

Fig. 6. Dorsal aspect of a fragment of the body-chamber.

7. Right lateral aspect of the same.

Arietites obtusus, J. Sowerby, sp. (p. 93).

Fig. 8. Left lateral aspect of a portion of a specimen, showing the muscular scar on the inner portion

of the outer whorl opposite the arrow.

9. Right lateral aspect of the same.

10. Ventral aspect of the same, showing the liuguiform impression on the central portion, and

anterior to it an /-shaped incised line in the depression on each side of the keel.

Lytoceras fimbriatum, J. Sowerby, sp. (p. 91).

Fig. 11. Dorsal aspect of the posterior portion of the body-chamber, exhibiting the left and a portion

of the right muscular scar.

12. Left lateral aspect of the same.

Lytoceras cornucopite, Young & Bird, sp. (p. 91).

Fig. 13. Dorsal aspect of the posterior portion of the body-chamber.

14. Right lateral aspect of the same.

15. Right lateral aspect of another specimen, showing the small oval scar on the inner part of the

outer whorl opposite the aiTOw.

16. Portion of same enlarged, showing muscular scar. X f .

17. Ventral aspect of portion of same enlarged, exhibiting the linguiform impression, x "f .

Plate 20.

Peltoceras sp. (p. 102).

Fig. 1. Dorsal aspect of fragment, showing the two elongated muscular scars. X ^.

^goceras capricorimm, Schloth., sp. (p. 95).

Fig. 2. Right lateral aspect. The muscular scar is the small white patch on the inner portion of the

outer whorl opposite the arrow.

j^goceras laqueolum, Schloenbach, sp. (p. 96).

Fig. 3. Dorsal aspect of fragment of body-chamber, showing the left muscular scar and part of the

right.

4. Left lateral aspect of the same.

ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 113

Hecticoceras hecticuni, Reinecke, sp. (p. 98).

Fig. 5. Left lateral aspect, x if .

6. Right lateral aspect of same. x %.

7. Ventral aspect of portion of same. X i'.

Distichoceras Baiigieri, d'Orbiguy, sp. (p. 100).

Fig. 8. Right lateral aspect, x j.

CEcotraustes crenatus, Bruguiere, sp. (p. 99).

Fig. 9. Right lateral aspect. X f.

Arietites raricostatus , Zieten, sp. (p. 94).

Fig. 10. Left lateral aspect of entire specimen.

11. Dorsal aspect of the portion ab, which is a natural internal cast of part of the body-chamber

showing at the base the remains of the two muscular scars.

Sonn'uiia sp. (p. 98) .

Fig. 12. Left lateral aspect, exhibiting the muscular scar on the inner portion of the outer whorl

opposite the arrow, and also the adjacent indentations.

Clymenia undulata, Miinster (p. 105.)

Fig. 13. Right lateral aspect.

14. Peripheral aspect of the same.

Glyphioceras crenistria, J. Phillips, sp. (p. lOG).

Fig. 15. Left lateral aspect. The fine white line opposite the arrow is the boundary of the annulus ;

the subtriangular patch into which it passes near the umbilicus is the left muscular sear,

the black line posterior to it is the edge of the last septum, the lighter portion near it being

the broken edge of the test.

16. Front view of the same, the arrow pointing to the line indicating the annulus.

17. Left lateral aspect of another example. The anterior septum is the base of the body-chamber.

The muscular scar is indicated by the light patch (opposite the arrow) on the piece of the

test, one layer of which is part of the floor of the body-chamber.

18. View of same from above ; the raised line on the piece of test wliicli is part of the floor of

the body-chamber being indicated by the white line marked a.

Glyphioceras tnmcatum, J. Phillips, sp. (p. 108).

Fig. 19. Left lateral aspect. X j.

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MUSCULAR IMPRESSIONS IIJ FOSSIL CEPHALOPODA.

LINNEAN SOCIETY OF LONDON.

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[VOL. VII. PART 5.

THE

^y/

/ 9

TRANSACTIONS

OF

THE LINNEAN SOCIETY OF LONDON.

OBSERVATIONS ON THE STRUCTURE AND MORPHOLOGY OF THE

CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES;

WITH SPECIAL REFERENCE TO THE GENUS GADUS.

BY

FllANK J. COLE,

DEMON.STRATOn OF ZOOLOGY, UNIVERSITY COLLEGE, LIVERPOOL.

{Comviunicnied by Pro^. W. A. Herdman, D.Sc, F.Il.S.)

LONDON:

PRINTED FOR TRE LINNEAN SOCIETY

BY TAVLOli AND FRANCIS. RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSB, PICCADILLY. W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

''■■' Ontoh(^r 1898.

[ 115 ]

V. Observations on the St7'nctiire and Moiyhology of the Cranial Nerves and Lateral

Sense Organs of Fishes ; tcith special reference to the Genus Gadiis. By Frank J,

CoIj'e, Demonstrator of Zoology, University College, Liverpool. [Communicated by

Prof. W. A. Herdman, D.Sc, F.B.S.)

AUG 20 >899

(Plates 21-23.)

Read 3rd March, 1898.

Contents.

Page

A. Introduction 116

B. Historical 117

C. Sensory Canals in General 120

Conclusions 120

D. Sensory Canals of Gadus morrhtia 122

(1) Supra-orbital Canal 122

(2) Lifra-orbital Canal 123

(3) Hyomandibular Canal 126

(4) Lateralis Canal 127

Supra-temporal Portion 127

Lateral or Body Portion 127

E. Gadus morrlMa and Gadiis virens compared . . 129

F. The Sense Organs on the Lateral line Canals . . 129

G. Other Sense Organs belonging to the Lateral

line System 131

H. Eelation of the Sensory Canals to the SkuU . . 131

Conclusions 132

I. The Trigemino-facial Ganglionic Complex .... 133

J. Morphology of the Facial Ganglion 136

(1) Conclusions 142

(2) Typical Branchial Nerve 144

(3) Facial Nerve of Man 144

K. Morphology of Jacobson's Anastomosis 145

Conclusions 147

L. Metamerism of the Lateral line System .... 148

(1 ) Conclusions 152

(2) Value of the Lateral line Nerves 154

M. Innervation of the Sensory Canals in Gadus . . 156

(1) Supra-orbital Canal 156

Superficial Ophthalmic Trunk 156

SECOND SERIES. — ZOOLOGY, VOL. VII.

Page

(2) Infra-orbital Canal 158

Buccal Trunk 158

(3) Hyomandibular Canal 161

Hj'omandibular Trunk 161

(4) Lateralis Canal 164

Laterahs Trunk 164

N. Structure and Morphology of the R. lateralis

accessorius (" trigemini '") 166

(1) Condition in Gadus 17.5

(2) General Conclusions 177

0. Morphological Value of the Lateralis Nerve of

Petromyzon . 178

Conclusions 179

P. Gadus compared with other forms 179

Amia 181

Q. The Lateral Sense Organs of Vertebrates and

Invertebrates 185

Conclusions 186

Iv. The Phylogeuy of the Sensory Canals 187

Conclusions 192

S. The Lateral Sense Organs and the Auditory

Organ 194

Conclusions 197

T. Special Considerations 199

(1) Friant (1879) 199

(2) Morphology of the Facial Nerve of

Fishes 200

Summary 203

Bibliography 20U

17

116 MB. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

A. Introduction.

1 HIS investigation was first suggested to me as a desirable study by my former teacher,

Professor J. C. Ewart, F.R.S., some years ago. I had at the time contemplated worknig

at a Pleuronectid fish^ — allured by the problems which the asymmetrical head affords ;

but it was pointed out that I should be better equipped for such difficult work were I to

study a modern symmetrical Teleostean first, and that in fact it were almost an impossi-

bility to understand the former without having first investigated the latter. I therefore

abandoned my first project, and decided to work out the anatomy of the lateral line

system and its nerves on the common Codfish. That this work was necessary, and

indeed essential to the proper understanding of this complicated system, is very obvious

from a perusal of the literature. In spite of the enormous bulk of the latter, and the

ponderous theses and memoirs tlmt have been written on the subject of the present

communication, we still know very little about the fine anatomy of the lateral line

system, and very few authors have taken the trouble to grapple with the literature and

to conduct their investigations on a strictly logical and scientific basis. To Mr. Edward

Phelps Allis, who must be regarded as the pioneer in this work, vertebrate morphology

owes much. He was not only the first to make a comjilete study of the topographical

development of the lateral canals, and to give a correct and detailed account of their

innervation, but many important morphological deductions have been directly inspii-ed

by his work. This author has recently completed his work on Jmia. It is a completion

upon which I may be permitted to cordially congratulate the author, and to express the

hope that he will continue on other forms the studies he has pvn-sued with such

conspicuous success on Amia. Ewart has followed Allis with an account of his skilled

dissections of the very complex lateral line system of Lcemargus and Rata, and Pollard

has added some details on the ancient Siluroid Teleosteans. Pinkus has very largely

filled in a gap by an able account of the nerves of Protoptertis, and the writer has

published a description of the system in Chimcera. The most pressing want, therefore,

was an investigation of the details in a modern specialised Teleostean, and the pi-esent

memoir is largely an attempt to supply this deficiency in our knowledge of this

interesting apparatus in Gadus.

The experience gained whilst working under Professor Ewart, and afterwards in

investigating Chimcera, has been most valuable in the interpretation of the nerves of

the Codfish. That the skeleton of this creature represents a very specialised condition

is a palaeontological fact, and it is hence not surprising to find its nerves in an equally

advanced stage. My previous work on the simpler cartilaginous fishes (most of which

has yet to be published) has prevented me from going astray in the interpretation of the

nerves, and has enabled me to see in the specialised Cod the disguised form of the

primitive cartilaginous fish. The separation of the components in the Cod has necessarily

been effected with the microscope, and one cannot urge too strongly the importance of

this instrument in the elucidation of cranial nerve morphology. Investigations based

solely on microscopic or naked-eye anatomy olten contain gross but pardonable errors ;

and whilst, on the other hand, a combination of the two methods docs not indeed remove

THE CRAISIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 117

the possibility of error, it certainly reduces mistakes to within a somewhat reasonable

limit. Had I relied entirely upon sections, I should (as Pollard actually did) have

described the lateralis accessorius as a modified lateral line nerve ; whilst, had I confined

myself to naked-eye dissection, the very interesting condition of the " facial ganglion"

would have entirely escaped observation.

Pigure 1 (PL 21) and the description of the sensory canals themselves (pp. 122-129)

are based on the dissection of a single specimen, which, as shown in the Plate, had its

anterior and posterior narial openings abnormally fused together. The right side, how-

ever, was normal in this respect. This specimen measured 237 mm. from tlie snout to the

anterior extremity of the dorsal tin *, 210 mm. from the snout to the dorsal attacliment

of the opercular fold, and 80 mm. from the barbel to the apex of the mid-ventral ano'le

formed by the fusion of the two opercular folds. Its girth from the anterior extremity

of the dorsal fin to the dorsal border of the base of the pelvic fin was 195 mm.

The young Gadus vire/is used in the microscopic part of the work were obtained at

St. Andrews, where, on this as on many other occasions. Professor W. C. Mcintosh,

P. U.S., very kindly placed a table in his admirable new laboratory at my disposal.

I also have to thank him for collecting the material and keeping it alive in the tanks

when the exigencies of teaching left little time at my disposal. The smallest specimen

I brought away from St. Andrews was 35 mm. long, but those sectioned were larger

than that. They may therefore be described as young adults.

To Professor G. B. Howes, P.Pt.S., I am indebted for much kindly assistance and

encouragement, and indeed both to him and to my valued chief. Professor W. A.

Herdman, F.R.S., I owe " many acts of kindness that I can never repay, and have no

wish to, for I prefer continuing the obligation." The preparation of the bibliography,

of which a section is printed at the end of this paper, and which will be published

separately wdien completed, has necessarily laid me under obligations to many librarians,

as well as to Professor Howes. Of these I should like to mention Mr. A. W. KajJiiel, of

the Linnean Society ; Mr. P. H. Waterhouse, of the Zoological Society ; Mr. A. H. White,

of the Ptoyal Society; and Mr. B. B. Woodward, of the Natural History Museum.

To these gentlemen, who freely placed their knowledge and time at my disposal, I must

express my heartiest thanks,

B. Historical (G^i-f^s) t-

The first reference I find to the sensory canals and cranial nerves of the Cod is

contained in the work of Monro (144) published in 1785. Monro considered the lateral

canals glandular oi'gans (i. e. " mucous canals "), and gives a large but superficial figure

of Gadus in plate v., which shows the supra-orbital commissure and the median

unpaired tubule, but which overlooks the supra-temporal canal. This author was the

* The point of extension forward of the dorsal fin is extremely variable even in the same species, as may readily

be seen by comparing common Cod placed side by side in a fishmonger's shop.

t I purposely omit references to text-books that are in constant use, such as T. J. Parker's ' Zootomy,' &c. [Since

this section was written, several other Oadus references have been encountered, but these will be fully treated in my

complete Bibliography.]

17*

118 MR. F, J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

first to discover the nerve-supply of Lorenzini's ampuUse in Selachians. In 1825

Desmoulins and Magendie (60) gave a figure of the brain and roots of the nerves of

the Cod, whilst Giltay in 183i (88) figured and described the sympathetic nervous

system, of wliich more presently. Leuret and Gratiolet, in a fine work (1839-1857, 119)

treat of some Invertebrate nervous systems, and give a brief account of the central

nervous system and cranial nerve roots of a few fishes, including the Cod, as also does

Alcock (3, 1839).

In 1842 Stannius (198) commenced his studies on the peripheral nervous system, and

published a careful description of the nerves of "■ Gudus callarias" {=G. mor/'hua).

The results obtained on this form were included in his well-known general treatise

published in 1849, which will be discussed elsewhere. In the same year he wrote a

short note on the lateral canals of fishes (197), in which he briefly but accurately

describes the lateral canals of " Gadus callarias^ He corrects Monro's mistake re tlie

supra-temporal canal, and devotes a few lines to the nerve-supply, remarking that the

supra-temporal lateral line nerve is homologous with the Ramus auricula ris vagi of

higher Vertebrates. This homology can, of course, be maintained no longer.

Bonsdorff', in 1846 (30), gives us one of an admirable series of papers on cranial nerves,

and treats of the trigeminus and cephalic sympathetic of " Gadus lota " [=Lota

vulgaris). He gives a good figure of the brain and nerves, but in his interpretation of

the latter was greatly misled by comparing them in too much detail with the Mammalian

nervous system. Stannius's monograph (1849, 199) is concerned largely with Gadus,

and will be discussed further in the text. Besides giving a fine figure of the lateralis

accessorius, and showing further its connection with the spinal nerves (in " Gadus

callarias "), he gives a further figure of the cephalic sympathetic and arteries in the

same animal. Leydig (1850, 120) was the first to describe the histology of the lateral

sense organs in Lota vulgaris, and shoAvs the lateral line ossicle with its sense organ and

perforating nerve. In Swan's beautiful atlas (1804, 205) there are several good figures

of our type, but tlie accompanying text is unfortunately very meagre. The figure of

the Cod's brain and nerves here given has been copied into several text-books, and may

be seen in the first volume of Owen's 'Vertebrates,' p. 298.

In Traquair's work on the asymmetry of the Pleuroneotidse (1865, 207), the first

accurate account of the topography of the sensory canals of Gadus and their relations to

the bones of the skull is given. A figure (tab. 32. fig. 1) is published indicating the

approximate position of the various canals (omitting details), and Dr. Traquair puts to

brilliant use the lateral line system in sustaining his views on the Pleuronectid skull,

Owen (1866, 149) makes some references to the nerves of the Cod, but his statements

and figures are compiled from the works of Swan, Alcock, and Cuvier and Valenciennes.

The histology of the brain of " Gadus lota " has been treated of by Stied;i (1868, 201),

who examined tiie nerve-tracts in the brain and spinal cord, and devotes a few notes to

the roots of the nerves.

A very important work, historically, which has hitherto been overlooked, and to whicii

I shall refer in some detail later on, was published in 1879 by A. Friaat (73).

This author describes and figures the brain and nerves of many bony fishes, including

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF EISHES. 119

" Oadus carbonarius'' {=G. vlrens) (pi. v.) and " Gadus lota" (pi. vi.), and his work

is remarkably accurate for the time it was published, anf'^ must certainly be regarded as

a pioneer research. Cunningham (1890, 55) says (p. 77) : "In the Cod, which may be

taken as exhibiting pretty nearly tlie original condition of the cephalic tubes of the Sole

and other tlat flshes, tliere are no superficial sense-organs on the head, and the tubes of

the two sides are symmetrically arranged." Omitting the last, I cannot acquiesce to any

of these statements. The lateral sense organs have xicdoubtedly advanced purl passu

A\ith the development of the skull and the evolution of the asymmetry of the Pleuro-

nectidge. Cunningham's figure of the sensory canals of the Cod is copied " with slight

modifications " from the figure given by Traquair in his Pleuronectid paper. Traquair's

figure, as far as it goes, is perfectly accurate, and I must confess that Cunningham's

modifications are somewhat unfortunate — especially the one that connects the liyo-

mandibular with the lateralis canal. Further, the statement as to the absence of

superficial sense organs is a curious oversiglit, especially as the mandilnxlar line of pit

oi'gans is more obvious than these organs are in any other fish I am acquainted with.

Allis, in his last Amia paper (1S97, 6), makes some passing references to Gadus, which

he states are based on work being done in his laboratory by Dr. Dewitz and Mr. Samuel

Mathers. On p. 631 he says : — " In Gadus there is a line of surface organs on the outer

surface of the opercular bones immediately behind the preoperculum. They are all

innervated by a special branch of the mandibularis externus facialis, and are therefore

of the character of pit organs, and unquestionably represent in Gadus one of the cheek-

lines of Amia or a similar line not found in Amia." Again, on pp. 032-633: — '' h\

Gadus a line of surface organs is found along the lower edge of the mandible, parallel

to the mandibular canal, and it is innervated by a long branch of the externus facialis,

which first runs forward through the adductor mandibuUe, to tlie hind edge of tiie

infraorbital canal behind the eye, and there turns downwards and reaches the mandible.

A nerve in Esox corresponding in position to this nerve in Gad/is innervates a line of

surface organs lying on the upper jaw immediately below the infraorbital canal."

Respecting the innervation of the latter organs lie says (p. 637) : — " Tiiis nerve [/. e. a

branch of the externus facialis] in Silurus may l)e a l)ranch cori-esponding to the one

which in Amia innervates the mandibular line of pit organs, and in Gadus innervates

a mandibular line of the slit like organs peculiar to that fish."

Finally Goronowitsch (1897, 90) has given an admirable account of the trigemino-

facial complex of JLoia vulgaris, in which tlie histology of the medulla and the nerve

tracts of the ganglionic complex are ably elucidated and described.

It is thus seen that our knowledge of the lateral sense organs and their associated

nerves in Gadus is still of a vei'y imperfect description, and in fact all the work of any

pretension was done before the lateral line system w'as properly understood, and l)efoie

the researches of Allis, Ewart, and Strong had placed our knowledge of this interesting-

system on a secure basis of carefully ascertained fact and logical deduction. It is the

purpose of the present communication to supply this defect, to add some new facts 10

our knowledge of the lateral organs, and jJerhaps to elucidate many points that are still

somewhat obscure. I find with Allis that " as the work has j)rogressed it has repeatedly

120 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

been found necessary to study details, and to include in the investigation whole

subjects not contemplated in the beginning." The more important additions are the

sections on the lateralis accessorius (which I trust is here correctly understood for the

fii'st time), the phytogeny of the lateral canals, the relations of the latter to the auditory

organ, the metamerism of the lateral sense organs, and the morphology of the " facial "

ganglion and Jacobson's anastomosis. Hence the somewhat comprehensive title of the

present communication.

C. Sensory Canals in General.

The sensory canals of the Cod differ in no essential respect from those of the typical

form. Indeed the uniformity that exists in this connection, even amongst fishes of

widelv different classification, is one of the most remarkable incidents in the history of

this remarkable system. The same fundamental plan may be seen in all, whether we

take an Elasmobranch, a Holocephalan, a Dipnoan, a "Ganoid," or a " Teleostean."

Even in the Palaeozoic Coccosteaus and Asterolepids, we see, thanks to the admirable and

laborious researches of Traquair, the same generalised type. In Coccosteus, for example,

we may consider the horizontal canal traversing the anterior dorso-lateral, ihe external

occipital, and the central plates, as the lateral or body canal. This, after a break, gives

rise to a supra-orbital canal, traversing the central and pre-orl)ital plates, and an infra-

orbital, situated on the central, post-orbital, and maxillary ossicles. Tliere is also a

supra-temporal commissure situated on the two centrals, and this probably marked the

anterior extremity of the lateral canal. The hyomandibular series is represented by

canals on the post-orbital, marginal, and maxillary, and perhaps by the other canals in

this region. In PtericJithi/s, again, the sensory canals are very simplified, being reduced

to representatives of the lateral and iafra-orbital canals, the former being connected

anteriorly on the median-occipital plate by the supra-temj)oral commissure. Here the

practical absence of a supra-orbital canal is perhaps correlated with the curious condition

of the orbits in the Asterolepid fishes.

As I have elsewhere maintained (46, p. 181), and as the pioneer researches of Allis

must be held to have established, the sensory canal systems of fishes, both recent and

fossil, may be reduced to a common type. Pending the production of weighty evidence

to the contrary, this must be considered as one of the best-established conclusions

attained by the careful study of these organs by many able observers. This common

type may be summarised as follows : —

(1) A supra-orbital canal passing, as its name implies, over the eye. Innervated by

the superficial ophthalmic lateral line nerve. Anteriorly may anastomose with the

infra-orbital canal or end blindly ; posteriorly anastomoses either Avith the infra-orbital

or lateral canal, but more often with the former.

(2) An infra-orbital canal coursing underneath the eye. Innervated by the buccal

-l-otic lateral line nerves. Anteriorly may anastomose with the supra-orbital canal or

end blindly ; posteriorly anastomoses either with the lateral canal only or with both

the supra-orbital and lateral canals (usually).

THE CRANIAL NEKVES AND LATERAL SENSE ORGANS OF FISHES.

121

(3) A hyomandibular or operculo-mandibular canal. Developed in connection witJi

the lower jaw, and may be represented by one or more canals. Innervated by the external

mandibular lateral line nerve. Ventrally may anastomose with its fellow or fellows of

the opposite side, but usually ends blindly ; dorsally usually anastomoses with the infra-

orbital canal, may in some cases do so with the lateral canal, may anastomose with botli

these canals, or may remain independent of any.

Figure of Gadus virens. half natural size, showing the sensory canals and their innervation — the latter imlicatefl by

the different kinds of shading. D.F. anterior extremity of dorsal fin; Z,'. supra-temporal portion of lateralis

canal ; L\ lateral portion of lateralis canal ; iV\ anterior and posterior narial openings ; 0. opercular fold ;

PcT.F. pectoral fin; Plv.F. pelvic fin; P.O. pit orgms (innervated by the lateral line nerves) ; S.O.C. supra-

orbital commissure.

(1) Supra-orbital canal, S.O. Innervated by superficial ophthalmic lateral line nerve — eroBS-hatched.

(2) Infra-orbital canal, F.O. Innervated by buccal + otic lateral line nerves — dotted.

(S) Hyomandibular or Operculo-mandibular canal, H. Innervated by external mandibular lateral line

nerve — longitudinal shading.

(4) Lateralis canal, D and L'^. Innervated by lateralis lateral line nerve — oblique shading.

(4) A lateral canal situated at the side of the body. Innervated by the lateralis

lateral line nerve. Anteriorly anastomoses usually with the infra-orbital canal only,

but may also do so with the supra-orbital canal ; posteriorly ends blindly at the tail.

The canal known as the supra-temporal or occipital commissure ( = Commissural canal of

Ewart) has somewhat variable relations, and is perhaps not homologous in all fishes.

122 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

Strictly speaking, and arguing from its condition in those fishes in which its innervation

has heen carefully ascertained, it should form a dorsal connection hetween the anterior

extremities of the lateral canals. It may, however, interpolate itself, as it does in

Cliimcera and other recent fishes, and perhaps also in Pterichthys, hetween the two

orhital canals, so that these do not anastomose posteriorly, hut hoth arise from the lateral

canal. But, however this may he, no canal can he considered a supra-temporal canal

which is not innervated by the lateralis nerve, and which therefore is not a portion of

the latei-al canal.

I hence propose to describe the sensory canals of Oadus morrJiim in the following

order : — (1) Supra-orbital canal ; (2) Infra-orbital canal ; (3) Hyomandibular canal ;

(4) Lateralis canal. All these canals will be described from before backwards.

D. Sensory Canals of Gabus morrbua. (PI. 21, fig. 1.)

(1) Supra-orbital Canal.

The supra-orbital canal commences blindly at the anterior extremity of the nasal bone,

and therefore of course at the extremity of the snout. This blind extremity appears

very late in the ontogeny of the system, and is not seen in sections of young Gadids — the

canal here being directly continuous Avith the first dermal tubule (I propose to designate

as " dermal tubules " those small tubes by which at intervals the main sensory canals

communicate with the surface *). The supra-orbital canal on the nasal bone pursues a

slightly sigmoid course obliquely inwards, upwards, and backwards, and measures whilst

on this bone about 40 mm. long. The nasal is deeply grooved to receive the base of the

canal, and its inner edge is jmrtly turned outwards to form a rough tube — imperfect,

however, dorsally and externally. Anteriorly the bony nasal furrow is imperfect ventro-

lateially, in order that the fii'st dermal tubule may enter the supra-orbital canal (see

PI. 21). The second dermal tubule enters the supra-orbital canal 25 mm. from the

posterior extremity of the nasal, and lies in a backwardly-directed oblique furrow situated

on the lateral wing of the nasal.

The canal now leaves the nasal and for a distance of about 5 mm. has no bony floor,

but only a ligamentous one. An internal wall and roof are, however, partly supplied by

a forward projection of the frontal. The third dermal tubule enters the canal at this

region, but somewliat nearer the frontal than the nasal.

The remainder of the supra-orbital canal on the frontal is more conveniently described

from behind forwards. In front of its anastomosis with the infra-orbital it courses

inwards and forwards for a distance of about 20 mm. It then enters by a lateral

foramen a canal bored in the substance of the frontal. Tiie median portion of this canal

forms a perfect tube, but posteriori}^ the roof is imperfect owing to the jiresence of a

* The dermal tuLules and sense organs of the lateral canals are enumerated in order from before backwards

in full knowledge of Allis's important proof of the relation between the sense organs and the tulnilcs. Any

scientific enumeration of these structures in the ease of the Cod is, however, impossible until the development of

both has been investigated, and any attempt therefore to do so here would be purely arbitrary and misleading.

THE CEANIAL NEEVES AND LATERAL SENSE ORGANS OE FISHES. 123

long, laterally compressed, oval median fontanelle, which measured 12 mm. long in the

present sjDCcimen. The posterior extremity of this fontanelle represents the nearest

approach which the supra-orbital canal makes to the mid-dorsal line, the two supra-

orbital canals being only separated at this region by a cylindrical bony basal projection

or septum 3 mm. wide. It is here that the two supra-orbital canals communicate Ijy a

well-marked transverse commissure, very obvious in sections of young Gadids, but apt

to be overlooked in dissections of adults. In front of this region the canal at once

liegins to course obliquely outwards, and continues to do so as far as its anterior

extremity. The bony septum above I'eferred to becomes wide at the anterior extremity

of the fontanelle, where it is nearly 5 mm. wide. The median closed portion of the

tube is a little over 10 mm. long, in front of which the next 14 mm. of the canal

are imperfect externally, becoming more and more so anteriorly. The course of the

supra-orbital canal from the posterior extremity of the median fontanelle up to tlie

anterior edge of the frontal has been slightly obliquely outwards and forwards.

The fourth mipaired dermal tubule, which is the longest of those opening into the

supra-orbital canal, enters it at the short transverse commissure. The surface pore in

adults is, in all the specimens that I have examined, slightly to the left of the median

dorsal line, whilst the tubule itself opens precisely at the centre of the commissure,

although I have seen it also somewhat to the left. In sections of young Gadids, however,

both the surface j)ore and the internal opening are exactly median — another instance of

the slight disturbance of the symmetry of the lateral line organs which lakes place in

the adult. It may be mentioned here that this is the only unpaired dermal tubule in

the Cod.

(2) Iiifra-orhital Canal.

This will be described under the headings of the various bones which support it.

First Suh-orhital or Lachrymal Bone *. — The infra-orbital canal arises blindly a little

in front of the lachrymal near the mid-dorsal line at the extremity of the snout; The

blind extremity exists from the very beginning, and is obvious both in sections of young

forms and in dissections of the adult. The anterior extremity of the lachrymal is grooved

to receive this part of the infra-orbital canal. The lachrymal itself is roughly triangular,

with the apex directed forwards. Its length is about 60 mm., and breadth at the base

over 35 mm. The base may be divided into two concave portions, separated by a median

* The synonymy of the bones of the Teleostean skull is, it is hardly necessary for me to point out, a somewhat

obscure subject. I have endeavoiu-ed as fur as possible to steer a middle course, and therefore hope that no objection

can be taken to any of my terms. It is, perhaps, necessary to exjilain that Allis (6) and other authors consider the

first sub-orbital and lachrymal to he two separate bones. No reasonable objection, however, can be brought against

the view advocated by McMurrich (136), that the lachrymal is a modified sub-orbital plate, and I therefore describe

it as the first sub-orbital. "We may note in this connection that the Teleostean lachrj-mal has been erroneously

termed by some authors the pre-frontal. The correct homologue in the Teleosts of the Ganoid pre-froutal is,

however, the lateral ethmoid (=the parethmoid). For the rest, sphenotic and pterotic are undoubtedly synonyms

of post-frontal and squamosal respectively (but see p. 132). The confusion in the nomenclature of the bones of the

fish's skull has arisen partly by the misuse of some terms and partly by the unnecessary introduction of others.

SECOND SERIES. — ZOOLOGY, VOL. VII. 18

124 ME. F. J. COLE ON THE STRUCTUEE AND MOEPHOLOGY OF

prominence, the ventral portion bearing a facet for the articulation of the second

sub-orbital. The sensory canal passes along the middle of the bone, marking it into two

almost equal halves. The dorsal border of the canal is slightly sigmoid, and anteriorly

it aj)proaches the border of the upper jaw, whilst the direction of the whole canal is

distinctly downward. A thin bony lamina (see below) projects downwards from above

and forms a roof and an external border for this portion of the infra-orbital canal, leaving

it open, however, ventrally. About 35 mm. from the posterior extremity of the lachrymal

this bony lamina is seen to be l)roken, thus forming a sort of notch and leaving this

portion of the infra-orbital canal wdthout any external boundary, and with only a portion

of its roof. The first four dermal tubules open into the iDfra-orbital canal on the

lachrymal, the first at the anterior extremity of the bone, and the tbird at the notch

mentioned above.

The articulation of the lachrymal with the second sub-orbital is somewhat peculiar

and may here be descrilied. As mentioned above, and as is the case with the other

sub-orbitals, the lachrymal sends down externally a bony lamina the function of which is

to protect the external wall of the infra-orbital canal. With the posterior extremity of

tbe imperfect tube thus formed the dorsal portion of the anterior convex extremity of the

second sub-orbital becomes fitted or wedged in. Ventral to the external bony lamina

the second sub-orbital simply overlaps the lachrymal, and the large facet thus formed at

the posterior extremity of the latter bone measures 6 mm. antero-posteriorly.

Second Sub-orbital. — The direction of this ossicle is backw^ards and downwards. Its

length dorsally at the sensory canal is about 20 mm., and its greatest width 22 mm.

Tlie anterior articular surface is convex, and is connected with the lachrymal in the way

above described. Posteriorly there is an oblique articulation with the third sub-orlntal.

The second sub-orbital is a large semi-cartilaginous plate, the dorsal border of which is

turned over so as to form a stout support for this portion of the infra-orbital canal. As,

however, the dorsal border does not fuse on to the large body of the plate ventral to the

sensory canal, the tube is imperfect ventrally, and is, in fact, only comj)leted by the

ligamentous sheath of the ossicle. The dermal tubules 5 and 6 open into the infra-

orbital canal on this ossicle — the former at the anterior extremity, where it overlaps tlie

lachrymal, and the latter near its posterior border.

Third St(l)-orbital. — This ossicle continues the downward direction of its predecessor,

but is somewhat more horizontal. The infra-orbital canal is still passing backwards and

downwards. The length of the third snb-orl)ital is 15 mm., and its width 16 mm. The

anterior and posterior articular surfaces are oblique and roughly parallel, but the anterior

is much the longer. An imperfect tube for the lodgment of the sensory canal is formed

in the same way as in the second sub-orbital. The seventh dermal tubule opens into the

canal at the posterior extremity of the third sub-orbital.

Fourth Sub-orbital. — The infra-orbital canal now begins to take an upward turn, and,

in consequence, the direction of this ossicle is upwards and backwards. It is further

midw^ay betw ecu the vertical and horizontal sub-orbitals, and measures 14 mm. in length

and 7 mm. in width. The sub-orbitals thus narrow from before backwards. The sensory

canal tube is formed similarly to those on the preceding sub-orbitals, but it must be noted

THE CRANIAL NEEVES AND LATERAL SENSE ORGANS OF FISHES. 125

that as the sub-orbitals become narrower, so the edge turned over to form the tube

approximates more and more to the ventral or posterior edge, the tendency thus being

for the whole of the sub-orbital ossicle to be nsed up in the formation of the protective

sensory tube. The eighth dermal tubule opens at the dorsal or posterior extremity of

the ossicle, the latter tapering off to receive it.

Fifth Sub-orbital or First Post-orbited. — The iufra-orbital canal has by this time taken

a sharp upward curve, so that the fifth sub-orbital is not far removed from the

perpendicular. Its length is 17 mm., and the anterior edge almost approximates to the

posterior in the formation of the tube lor the iufra-orbital canal. The ninth dermal

tubule is received by the infra-orbital canal betweca the fifth and sixth sub-orbitals.

This tubule is not rej)resented in Gaclus virens.

Sixth Sub-orbital or Second Fost-orbital. — This, the last and most posterior sub-orbital,

articulates ventrally with the fifth sub-orbital, and dorsally with the postero-lateral region

of the frontal, and also slightly with the post-frontal or sphenotic. Its direction is as

near as possible perpendicular, and the portion of the infra-orbital canal that it lodges is

of course directly continuous with that on the frontal. The length of the canal on the

sixth sub-orbital is 14 mm., and it is protected in a precisely similar manner as on the

fifth sub-orbital — the anterior and posterior edges not quite approximating.

Frontal. — The infra-orbital canal is now on the frontal. Situated on the upper surface

of the postero-external angle of the frontal is a triangular fossa with the apex directed

inwards and forwards. The base of the triangle forms a portion of the posterior edge of

the frontal. The infra-orbital canal comes first along the outer side of the ti-iangle (a

distance of about 14 mm.), and arriving at the apex first of all anastomoses with the

supra-orbital canal, and then turns sharply backwards, edging the inner side of the

triangle (about 15 mm.). The canal, therefore, at this region turns first inwards and

forwards, and then outwards and backwards. The two sides of the triangular fossa on

the frontal are depressed so as to form slight furrows for the reception of the base of the

infra-orbital canal. Further, the inner side of the triangle is raised up and arches

outwards, thus forming a roof for this portion of the infra-orljital canal. As, however,

elsewhere, the tube is imperfect externally.

Post-frontal or Sphenotic. — The sphenotic now comes to the surface and lodges the

next 5 mm. of the infra-orbital canal, the latter stUl pursuing the downward and

backward direction of the portion immediately preceding it on the frontal. The

sphenotic, however, only supports the floor of the infra-orbital canal, an inner wall and

roof being here formed partly by a backward projection of the frontal and partly by a

forward prolongation of the pterotic. Externally the sensory canal is only protected by

ligament. The tenth dermal tubule enters the canal at about the middle of the

sphenotic, and in front of the canal in that bone transmitting the otic branch of the

outer buccal nerve.

Squamosal or Pterotic. — The iufra-orbital canal, leaving the sj)henotic and still passing

backwards and somewliat downwards, enters on the pterotic, which supports it for the

last 30 mm. of its length, until, between the pterotic and the succeeding supra-temporal,

the infra-orbital canal anastomoses with the lateral or body canal. A more or less perfect

18*

126 ME. F. J. COLE ON THE STEUCTUEE AND MOEPHOLOGY OF

tube is formed on the pterotic by a latero-external process being sent down. Posteriorly

this process only forms an imperfect tiibe, but anteriorly it usually almost completely

encloses the canal, yet does not fuse ventrally with the floor of the ossicle. The tube

is thus imperfect for the whole of its length, but less so anteriorly than posteriorly. The

last or eleventh dermal tubule of the infra-orbital canal opens into it between the pterotic

and the adjoining supra-temporal, but the greater part of the aperture is on the pterotic.

(3) Hi/omandihula r Gmial.

The hyomandibular canal arises on the dentary at its anterior extremity near the

symphysis, its length, whilst on this bone, being about 80 mm. The direction of the canal

depends, naturally, on the position of the lower jaw. When the jaw is closed the canal

has a stioug upward incline. Its relations with the articular portion of the canal are, of

course, fixed, and do not vary with the gape of the jaw. The hyomandibular canal fits

into a deep groove on the ventral surface of the dentary which is continued almost to the

anterior symphysis. This groove is widely open ventrally, and gradually tapers towards

its anterior extremity. The first five dermal tubules open into the hyomandibular canal

whilst on the dentary, the sixth opening at the junction of the dentary and articular,

but rather on to the dentary.

Leaving the dentary the hyomandibular canal passes on to the articular, and then

begins the upward curve which carries the canal on to the pre-operculum. Strong dorsal

and ventral ridges form a stout protection for the canal, which is only exposed externally.

The hyomandibular canal is 15 mm. long on the articular.

Owing to an inward shelving on the part of the articular and pre-operculum, the next

10 mm. of the canal have no bony support, but are protected only by a ligamentous sheath.

This, of course, is developed in connection with the movement of the lower jaw. There

is also a strong upward curve on the part of the canal to meet the succeeding portion on

the pre-opei'culum. The seventh dermal tubule opens on to the canal at about the middle

of this ligamentous section.

Having reached the pre-operculum, the hyomandibular canal lies at first somewhat

horizontally. It then takes a graceful curve upwards, so that the posterior portion of the

canal is practically vertical. Whilst on the pre-operculum the hyomandibular canal has

a length of about 80 mm. A thin bony lamella projects downwards anteriorly and

backwards posteriorly, forming an external lateral wall for the canal, but, however,

leaving it open ventrally in front and posteriorly behind. Commencing at about 11 mm.

from the posterior extremity of the canal, a ridge of bone 8 mm. long is seen to be

thrown up, which forms a posterior wall for the canal. At this region the anterior bony

lamina forming the external lateral wall of the canal tapers down, otherwise the

hyomandibular canal would in this region be completely enclosed in bone. The tube then

is here also incomplete externally, but is inore perfect than it is at any other part of the

pre-operculum. The hyomandibular canal ends blindly 10 mm. below the dorsal

extremity of the pre-operculum. The dermal tubules eight to twelve open on to the

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 127

canal at the pre-opei'culum, the eleventh helow and the twelfth ahove the ridge of bone

just mentioned.

It is thus seen that the hyomandibuiai- canal is perfectly independent of any of the

others, and does not anastomose either with the infra-orbital or lateral canals.

(4) Lateralis Canal.

First or Supra-temporal Portion.

As with the infra-orl)ital canal, it will bo most convenient to describe the lateral canal

under the headings of its various supjiorting ossicles.

First Supra-temporal or Extra Scapula.— The supra-temporal canal commences blindly

in both G. morj^hua and G. vij'ens at the anterior extremity of the first supra-temporal

ossicle. Its direction is markedly inwards and forwards. The greatest length of the

ossicle is 17 mm., and its greatest breadth 6 mm. It is free anteriorly, that is, it has no

articulation with any otlier bone, but its extremity is attached by a ligament to the

dorsal spiny process of the parietal overhanging the foramen transmitting the so-called

" cutaneous branch of the Vth." * Posteriorly the ossicle articulates by means of an

oblique convexity with tlie second supra-temporal. The first supra-temporal consists of

an internal plate, having its dorsal edge turned over somewhat considerably to protect

the supra-temporal canal. Anteriorly the portion turned over tapers down to admit of

the entrance into the canal of the first or proximal dermal tubule.

Second Supra-temporal or Extra-scapula. — Supports the distal or basal portion of the

supra-temporal canal, and consists of an internal plate, the two edges of which have more

or less become opposed to form a tube. Posteriorly this apposition is complete, so that the

tube is here perfect, thougii the two edges in question have not fused, such not being a

characteristic of the Cod. Anteriorly, however, the tube, as in most of the other lateral

line ossicles, is imperfect, but this is to enable the second dermal tubule to eater the

canal. The upper posterior border of the ossicle bears a semicircular notch, which fits

into the upper or epiotic limb of the post-temporal. The internal face of the second

supra-temporal also rests on this limb of the post-temporal. The greatest length of the

second supra-temporal is 17 mm., and its greatest width about 11 mm. Anteriorly it

presents a concave border for articulating with the first supra-temjooral, whilst posteriorly

it articulates with two ossicles : a, by a long, slightly convex, ventral facet with the

third supra-temporal ; b, by a backwaixlly directed posterior facet (slightly concave) with

the fourth supi"a-temporal. Posteriorly the supra-temporal portion of the lateralis canal

takes a dowuAvard curve and becomes confluent with the latei-al or body portion.

Second or Lateral Portion.

The first 20 mm. of this section of the lateral cjinal are supported partly by the third

supra-temporal, biit also partly by the ventral jiortion of the second (see PI. 21. fig. 1).

This fact must be taken into consideration when reading the description of the former

ossicle.

* =the R. lateralis acoessorius (sec Section N, p. 16G).

128 MB. F. J. COLE ON THE STEUCTURE AND MORPHOLOGY OF

Third Supra-temporal or Extra-scapula. — The third supra-temporal is a somewhat

long bone supporting tlie anterior extremity of the lateral canal as it passes downwards

and backwards from the pterotic. Its greatest length is 22 mm., and its greatest width

9 mm. It consists of a plate slightly convex intei*nally, the dorsal edge of which is

turned over, but not very markedly, to form an imperfect tube. Its ventral border is

quite straight, whilst its dorsal border is somewhat irregular. Anteriorly it articulates

by means of an obliqvie and well-marked concavity with the pterotic, the dorsal border of

the third supra-temporal being prolonged forwards so as to fit into a corresponding

shelving on the pterotic. Ventrally the latter presents a large triangular facet 10 mm.

in length from base to apex, on w^hich the ventral portion of the anterior extremity of

the third supra-temporal rests and articulates. This articulation is very compact and

strong. Posteriorly the articulation is with two ossicles : a, by a long dorsal and

slightly concave facet with the second supra-temporal ; b, by an oblique concavo-convex

facet with the fourth supra-temporal. The third dermal tubule opened into the lateral

canal near the posterior extremity of the third supra-temporal, and slightly posterior to

the entry of the supra-temporal canal into the lateral. This tubule was present on the

left side of the fish, but not on the right.

Fourth Supra-temporal or Extra-scapula. — This consists of a flat internal plate 11 mm.

across at its widest part, and with a maximum length of 16 mm. Its dorsal edge is

turned over so as to form an external jirocess protecting the sensory canal. Anteriorly

it has a close ligamentous articulation with two ossicles : «, by a convexo-concave ventral

facet with the third supra-temporal ; h, by a slightly convex dorsal facet with the second

supra-temporal. The latter facet is internal to the first and passes back at an angle

to it. Posteriorly the fourth supra-temporal rests on and overlaps the angle formed by

the two forks of the post-temporal. The fourth dermal tubule opens into the lateral

canal near the centre of the fourth supra-temporal.

Post-temporal or Supra-scapula *. — The angle formed by the union of the two limbs of

the post-temporal now comes to the surface of the skull and supports the next 9 mm. of

the lateral canal. It is here that the lateral canal commences to approacli the surface

of the body and to take tip that position in which it is to be found immediately under

the skin. The fifth dermal tubule opens just at the posterior extremity of the post-

temporal, and almost between that bono and the first lateral line ossicle.

Behind the post-temporal the lateral canal loses the support of the bones of the skull

and pectoral girdle, and is only protected at intervals by the lateral line ossicles, which

themselves diminish posteriorly as the canal approaches the skin and decreases in size.

At about the middle of the fish the lateral canal lies immediately under the skin, and

is situated at the side of the body, its position being indicated by the modified scales

lying immediately over the canal. In the specimen from which the above description

has been written, it was about 55 mm. ventral to the anterior extremity of the dorsal fin.

It is supported behind the post-temporal by a series of imperfect bony cylinders, the

* The suin'a-elavicle of some authors (t'. (/. McMurrich, 136, and Gegeubaur). It is imiiossible, however, to

homologiso the boues usually termed post-temporal and supra-clavicle.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FLSHES. 129

so-called "lateral line ossicles." The anterior extremity of each "lateral line ossicle" is

2:)lacecl just posterior to the internal opening of a dermal tu1:)ule, so that if we regard the

lateral canal as composed of segments defined by the internal openings of the dermal

tubules and the intermediate occurrence of sense organs, then the lateral line ossicles will

lie at the anterior extremities of these segments. Each cylinder is imperfect externally,

the space being obliterated by the periosteal membrane. The length of one taken from

about the region of the pectoi-al fin was 7 mm. Anteriorly they increase in size, the first,

just posterior to the post-temporal, being an irregular imperfect tube 11 mm. long.

E. Gadus MoitiiHUA a:nd G. vibess compared.

The differences between these two species are few but decisive. The sense and pit

organs of both are the same {roughly as regards the pit-organs) both in number and

position. The only variations I could find were in the dermal tubules. These will be

at once noticed if a comparison be made between figs. 1 and 2, PLs. 21 & 23 (representing

G. morrlma and G. virens respectively), and are as follows :—

1. The ninth dermal tubule on the infra-orbital canal of G. morrlma is absent in

G. virens. This, as far as I am aAvare, is a perfectly constant difference. I have

never failed to find it in G. morrlma, nor have I ever seen it in G. virens.

2. In G. virens the hyomandibular canal opens anteriorly on to the surface, but does

not do so in G. morrlma. This, I believe, is another constant variation.

3. In G. morrlma the third dermal tubule of the lateral canal is of variable occurrence.

In the fish from which fig. 1 was drawn it was present on the left side, but absent

on the right. It will be noted that the nares also were abnormal in that fish on the

left side, being fused there, but quite normal on the right side. In G. virens the

fourth dermal tubule of the lateral canal of G. morrlma is, I have found, invariably

absent, nor have I ever seen any fusion on the part of the anterior and posterior

nares.

E. The Sense Organs on the Lateral line Canals. (Plates 22 & 23.)

These have been carefully worked out, as well as the number and position of the

dermal tubules verified, from sei'ial sections of G. virens. This is the only method which

ensures perfect accuracy in this connection. The sense-organs themselves not being

obvious to the naked eye, the dissector has to rely on finding the nerve twigs supplying

them. If he should chance to overlook one or more of these twigs, as often happens,

the corresponding sense organs are, for the time at least, also overlooked, and this may

easily nullify the results of the investigation. I accordingly paid a visit to St. Andrews

and collected a large number of young " Green Cod" {G. virens), many of which have

since been cut into serial sections. The heads of the living animals were cut off behind

the pectoral fin and fixed in Hermann's platinum acetic osmic mixture. The sections

(10 ticks thick, Cambridge rocking microtome) were stained on the slide with Mann's

methyl-blue — eosin* — a most admirable method, giving perfect pictures even of the brain

* Jouru. Anat. & Phys. vol. xsis. (N. S. vol. ix.), p. 100 (1894).

130 ME. F. J. COLE ON THE STEUCTUKE AND MOEPHOLOGY OF

and nerve tracts. The sense organs were then systematically mapped out from the

sections, so that it is hoped any possible chance of error has been removed.

Suxtra-orhitul Canal. — There are five sense organs on the supra-orbital canal as against

four dermal tubules. As a rule, one sense organ is placed midway between the internal

openings of two dermal tubules, so that there is usually a rough correspondence between

the number of sense organs and that of the tubules. The first sense organ on the supra-

orbital canal is placed between the openings of the first and second dermal tubules, but

nearer the second ; the second between the second and third tulmles, but nearer the

third (just over the anterior extremity of the nasal sac) ; the third and fourth anterior

and slightly posterior to the supra-orbital commissure respectively ; and the fifth near the

posterior extremity of the canal, and in the young forms * exactly dorsal to the optic

chiasma.

Infra-oi'hital Canal. — This canal has eleven sense organs and ten dermal tubules. The

first two sense organs are situated between the first and second tubules, and just under

the first sense organ of the supra-orbital canal. There is a slight overlapping on the

part of the first two sense organs, the j^osterior extremity of the first being above the

anterior extremity of the second, and the two together extending practically from the

opening of the first dermal tubule to the second. The next six sense organs, the third to

the eighth, lie between their respective tubules as shown in the figure ; the ninth and

the tenth, however, are not separated by a tubule, and this seems to imply that the ninth

dermal tubule has degenerated. This tubule is indeed present in G. morrhua, and in

such a position as would separate the ninth and tenth sense organs of G. vwens. It is

therefore possible that in the latter species the tubule has existed and disappeared. The

eleventh sense organ lies between the ninth and tenth tubules, but somewhat nearer the

former.

Hyomandihular Canal. — Twelve sense organs and thii'teen dermal tubviles were found

in connection with this canal. The first sense organ is slightly anterior to the opening

of the second tubule, and the second has the same relations with the succeeding tubule.

The remaining ten sense organs are situated between the openings of the tubules as

indicated in Plate 22 the last being placed on the narrow portion of the canal at its

posterior extremity.

Lateral Canal, — The supra- temporal segment of the lateral canal has two sense organs

and two dermal tubules, the first sense organ being placed slightly posterior to the

opening of the first tubule, and the second lying between the ojjening of the second

tubule and the junction of the supra-temporal portion of the canal with the lateral

portion. The third sense-organ is found just anterior to the junction of the two canals

mentioned above, whilst the fourth is placed betweeu the third and fourth dermal

tubules. The remainder of the sense organs of the lateral canal are situated as usual

between the openings of the dermal tubules. The condition of the lateral canal in young

Cod behind the operculum will be described and discussed elsewhere.

* See note on p. 150.

THE CEANIAL NERVES AND LATEliAL SENSE ORGANS OF FISHES. 131

G. Other Sense Organs belonging to the Lateral line System. (Plate 21.)

Belonging undoubtedly to the lateral line system, since they are innervated by the

same nerves, are the pit oi'gans or sensoi'y follicles, described by Merkel, Fritsch, AUis, and

Ewart & Mitchell *. These in the Cod are somewhat laiimerous, and do not occur in the

well-defined series that they do in the Elasmobranchs and Ganoids. Their structure

has already been fully discussed by the authors above mentioned, so that only a few

words are necessary as to their distribution. As will be seen by reference to tlie figure

of G. morrhua, the pit organs cannot be separated into groups, being too irregularly

scattered. It is equally obvious, however, that most of them occur in connection with

the sensory canals, and this is most marked in the case of the hyomandibular canal. In

spite of their apparent irregularity and number, they are very constant both in number

and position, as will be ascertained by a careful examination of an adult G. morrlina

and a comparison with the figure. The pit organs are usually conspicuous on account

of their pigmented lips, and even where this is slight or absent a contrast in colour

usually betrays their existence. As is well known, the pit oi'gans are excavated papillae

formed by an invagination of the skin, and lodging a sense-organ innervated by a twig

from one of the lateral line nerves. My figure (PL 21) of these organs is the result of a

minute examination of the heads of several large specimens of G. morrhua.

Contrasting with the numerous pit organs is tin; complete absence of any traces of

Lorenzini's amiiulUe and the associated ampuUary canals. Tliis fact is duly commented

on elsewhere.

H. PiElation of the Sensory Canals to the Skull.

That the lateral line system has no definite relations with the primitive skull is quite

evident even on a priori grounds. An epiblastic structvu'e, necessarily connected with

the skin, and actually found on the surface in Chim<era, or associated with it in many

forms, can only be secondarily connected with the skull. Except in the Elasmobranch

fishes, where the lateral canals are firmly embedded in the extensive subdermal tissue,

there is a tendency, almost in all fishes, to protect the sensory canals with some form of

calcified or rigid support. In Chimcera this takes the form of imperfect limy rings,

whilst in the majority of bony fishes the support ranges from a partial to an absolutely

perfect bony tube. There is, in fact, a strong tendency to surround the sensory canals-

with a complete extensive osseous deposit.

Such being the case, it becomes necessary to tlistinguisli between lateral line bones

and the cranial bones sensu stricto, and to enquire into the connection between the two

series where such must obviously exist. We may therefore divide the bones supporting the

lateral line into two series : — (o) ossicles developed purely for the support of the sensory

canals ; [h) cranial bones with which the lateral line ossicles have become secondarily

connected. The excellent work which has been done by McMurricli on the osteology of

Aminriis catus (1883-1, 136) has made perfectly clear the bearings of the lateral line

* See full discussion below.

SECONB SERIES. — ZOOLOGY, VOL. VII. 19

132 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

system on tlie morjiliology of the skull *. This author discovered the important fact

that the frontal bone, for example, consisted of two parts — the frontal projierly so-called

+ a fused lateral line ossicle. The supra-orbital canal in the region of the frontal first

acquired its bony support corresponding to a true lateral line ossicle, and the latter, as

development proceeded, became fused on to the frontal. The same process was observed

in the case of the sphenotic, pterotic, dentary, and articular. In the Cod this process

may be easily deduced from the structure of the articular portion of the hyomandibular

canal. We may therefore classify the osseous support of the lateral line in the Cod and

perhaps other forms as follows : —

Lateral line Ossicles. True Cranial Bones + fused Lateral line Ossicles.

Nasal.

Lachrymal or adnasal. Frontal.

Supra- or infra- (with post-) orbitals. Sphenotic (most forms).

Dermal Sphenotic {Amia)= the Post-frontal. Pterotic (most forms).

Dermal Pterotic {Gadiis) —the Squamosal. Dentary.

Supra-temporals. Articular.

Pre-operculum.

Two things must be pointed out with reference to this tabic: first, I fully agree with

McMurrich that the nasal and pre-operculumi are true lateral line ossicles ; second, there

is some doubt in the Cod as to the nature of the pterotic. In Amiurus there is no doubt

that it is a cranial bone bearing a fused lateral line ossicle. In Gadus, however, the

bone usually termed the pterotic has no connection with the ear, and may be easily

detached from the underlying ear bones. It seems probable, therefore, that the Cod's

"pterotic" is a lateral line ossicle which has not become fused on to the adjacent true

pterotic (cp. particularly p. 181) t-

Whilst it is obvious from these facts that the lateral line system has no connection

whatever with the primitive cartilaginous and membrane skull, such is by no means the

case with regard to the later development of the latter. Whilst, further, alcove the

Amphibia, the lateral canal system and its nerves completely disappear, leaving no traces

behind (omitting the auditory organ), we cannot say the same in the matter of the bony

supports of the canals. The nasal, for example, performs a doiible function — on the one

hand supporting a portion of the supra-orbital canal, for which purpose it was primarily

developed ; on the other hand, having relations with the nasal capsule, which represents

a. secondary modification. When, therefore, the supra-orbital canal disappeared, the

nasal would remain behind, to perform its accessory nasal function. It therefore seems

to me certain that the higher vertebrate skull bears very considerable traces of the

lateral line system of Fishes and Amphibians and it would be a very interesting study

to determine what these relations are. For example, admitting the homology between

the ear and the lateral line system, to what extent are the bones of the auditory capsule

profoundly modified lateral line ossicles ?

* MoMurr'.ch, by tho way, ulso considers the lachrymal to be the luodified first sub-orbital. So a'so does Pollard,

I,s02(i6o, p. 410).

t See Postscript, p. 20o.

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 133

The first author to recognise the important hearings whicli the lateral line system

might possibly have on the morphology of the skull was, I helieve, Dr. Traquair

(1865, 207), who, as I have previously pointed out, made considerable and skilful use of

the relation of tlie two structures in solving the problem of the asymmetrical skull.

Sagemehl (1883, 170), writing independently of McMurrich, says*: — "I desire to

mention, at this jioint, tliat hitherto the relations of the mucous canals to the bones of

the cranium have hardly been given a thought, and yet they deserve a closer study, as

these relations are very constant, and in questionable cases they can be used to determine

doubtful homologies." Allis (1889, 4) points out (p. 46i) that "it is only within the

last five or six years that the constant relations of the cranial canals to the dermal bones of

the head, and their imj)ortance in determining these bones in doubtfid cases, have been

recognised. Both Sagemehl and Van Wij he have called special attentioi: to this "

Since 1883, Sagemehl, Bridge, and numerous other authors have, when dealing with

the skull of bony fishes, also described the cranial sensory canals, with the result that the

relations of the lateral canals with the skull have been shown to be remarkably

constant. Hence the table given above may be said to represent the facts in most

bony fishes.

I. The Trigejiino-facial Ganglionic Complex.

General Statement. — As it is impossible to arrive at an accurate appreciation of this

complex by observations on the adult, the following description has been based upon a

study of sections of young forms. The trigemino-faeial ganglion in these sections is

seen to consist essentially of three portions arising by two roots, which are from above

downwards : —

(1) A Lateral line ganglion. Consists of two parts united in front, one being situated

ventral to the other. The dorsal part gives rise to the superficial ophthalmic

and buccal lateral line nerves, which arise as a single trunk and separate into

superficial ophthalmic and buccal trunks as a passage is made through the second

portion of the trigeraino-facial ganglion. The ventral portion is doubtless connected

with the external mandibular lateral line nerve.

(2) A " Trigeminal " or "Gasserian" ganglion t- This is situated internal and largely

anterior to the second or ventral portion of (1). From this portion of the

complex the superficial ophthalmic of the trigeminus, the maxillo-mandibular

trunk, and, probably, the post-branchial division of the facial arise. If the latter

statement be cori'ect, as seems certain, this ganglion should be called the

" trigemino-faeial."

(3) A "Facial" ganglion. This is a long and perfectly distinct ganglion which lies

ventral to (2). It is connected with the palatine nerves and also with the

* English translation by Shufeldt, p. 75i! (188.5, 1S7).

t I have called this ganglion the " trigeminal "' or " Gasserian " in order to distinguish it from the " facial "'

ganglion. The question of the latter is discussed liclow. It id sufficient to remark here that were it more distinctively

a ganglion of a cranial nerve, and less a sympathetic ganglion, the morphology of the "trigeminal" ganglion would

doubtless be less ditficult to decide.

19*

134 ]ME. F. J. COLE OX THE STEUCTUEE AND MOEPHOLOGT OF

pre-spii-acLilar or chorda tympani divisions of the facial. It also communicates

(a) directly with the sympathetic trunk ; (i) by means of Jacobson's anastomosis

(see below) with the glossopharyngeus.

In the adult Cod (see PI. 22. fig. 2) there are two roots to the trigemino-facial complex,

but these fu^se in such a Avay that it is impossible to follow the nerves through the point

of fusion. Nor is there any obvious ganglion beyond the lateral line ganglion (fig. 2,

X. G.). It seems to me to be proiiable that there are lateral line fibres in each root. The

roots are separated by the orbital vein.

Special Description. — The posterior or dorsal root of the trigemino-facial complex, as

seen in the sections, arises from the side of the medulla on a level with tlie dorsal border

of the horizontal semicircular canal and the j)osterior portion of the infra-orbital sensory

canal. Its posterior edge overlaps the anterior edge of the first acoustic root, and it

leaves the medulla at a level just dorsal to this auditory root. There is a slight mingling

of fibres between the two roots at the point where they emerge from the medulla,

but as both roots belong strictly to the lateral line system, this, happily, does not

introduce any complication.

On emerging from the brain the dorsal root swells into an external knob containing

ganglion cells ( = dorsal portion of (1) above), and then, internal to this knob, passes

straight dowuAvards internal to the vestibule of the ear and alongside and in front of the

first auditory nerve. No ganglion cells were seen on this descending part of the root.

As the dorsal root passes downwards ventral to the ganglionic projection just described,

another root is received which arises anterior and slightly ventral to the first, and passes

backwards to join it. At the point where the two roots join is another mass of ganglion

cells (= ventral portion of (1) al)0ve), and this second ganglionic enlargement itself

becomes augmented by a further collection of cells ( = (2) above) which lies internal and

largely anterior to it. In front the three ganglionic masses become closely o^jposed,

but the boundaries of all three can be easily distinguished.

That the trigemino-facial complex is in a somewhat specialised condition may be

inferred from the fact that the two roots just described are the only roots for the whole

complex — that is to say, they stand for the three anterior lateral line nerves as well as

for the trigeminal and facial cranial nerves. The precise course of the fibres of these two

roots through the ventral portion of the lateral line ganglion and the trigeminal ganglion

my sections failed to demonstrate, but the following facts were made out with tolerable

certainty. Setting aside the palatine nerves, which will be found described below, the

first nerve to issue from the trigemino-facial ganglion posteriorly is the hyomandibular

trunk. Tlie most ventral fibres of this trunk go to form a portion of the facial proper,

which is also described in connection Avith the facial ganglion. The passage of the

orbital vein splits the hyomandibular trunk into two parts — a postero-dorsal and an

antero-ventral. Along the former portion the cells of the second or " trigeminal "

portion of the compound ganglion, Avhich have hitherto been entirely intra-cranial, pass

outside the pro-otic notch and are spread over the dorsal portion of the hyomandibular

trunk outside the cranium and slightly external to the orbital vein. Distal to the vein

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 135

the two parts above unite and the fibres are almost immediately shuffled into two

bundles — a posterior and an anterior — described with the buccal trunk. The origin of

the facial proper fibres is mentioned in the description of the facial ganglion. The

lateral line fibres of the hyomandibular trunk seem to be derived from the ventral

portion of the lateral line ganglion.

In front of the liyomandibular the trigeminal ganglion lies partly within the cranium

and partly outside it, the orbital vein separating the dorsal trigeminal from the ventral

facial ganglion. The maxillo-mandibular -|- buccal trunks issue together from the

trigeminal ganglion. The former is connected with the trigeminal ganglion, and there

cannot be the least doubt that the latter passes upwards and backwards through the

same ganglion, and arises, in common with the superficial ophthalmic lateral line nerve,

from the dorsal pcn-tion of the lateral line ganglion. Some of the trigeminal ganglion

cells extend along the dorsal border of the maxillo-mandibular trunk. In front of the

exit of the raaxillo-mandilnilar + buccal trunk, the trigeminal ganglion tapers down and

gives off" the superficial ophthalmic division of the trigeminus which accompanies the

lateral line nerve of the same name as described below.

The facial ganglion is perfectly distinct from any other part of tlie complex and lies

entirely outside the skull. It commences anteriorly above the orbital vein, and

immediately ventral to the trigeminal ophthalmic, passing down\^ards and backwards,

and increasing in size so as to lie external to the orbital vein, and ventral and external

to the anterior extremity of the trigeminal ganglion. At this region a thin strand

pass(!s downwards externally and connects the dorsal with a ventral portion, which lies

immediately under the orbital vein. The ventral portion, therefore, does not extend as

far forwards as the doi'sal portion, whilst the latter only extends as far back as the

maxillo-mandibular + buccal trunk — at which point it ceases to exist. The ventral

portion, however, passes backwards under the orbital vein and internal to the above

trunk. Internal to this ventral portion the most ventral fibres of the hyomandibular

trunk pass downwards and outwards under the orbital vein and enter into relations with

the facial ganglion. The first branch to be given off' from these fibres passes through

the inner region of the facial ganglion, turning inwards, downwards, and forwards, and

passing among the muscles of the alimentary canal. The next branch passes almost

through the middle of the ganglion and courses forwards external to the previous

blanch. The third and largest branch passes obliquely through the centre of the

ganglion, turns inwards, and then divides to form two large nerves — one of which passes

forwards and the other backAvards. The forward division again divides, and represents

the true palatine branch of the facial nerve and its two divisions, the anterior and

posterior palatine nerves described by Allis in Amia. The posterior division passes

backwards and slightly outwards and accompanies the cephalic sympathetic trunk, but

lias otherwise no connection with it. It finally takes an upward aud outward turn and

passes into the ganglion of the glossopharyugeus. It thus represents the nerve known

as Jacobsoii's anastomosis, connecting the facialis with the glossopharyugeus. Tiie

remainder of the ventral fibres of the hyomandibular pass outwards with the latter

trunk and the facial ganglion, but apparently have no connection with it, and are

136 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OE

continued as the prc-spiraeular or chorda tympani division of tlie facial. The precise

orioin of tlie post-branchial or hyoidean branch of the facial has already been described

as doribtful from the " tripjeminal " ganglion, but there could be no doubt as to the

association of the palatine and chorda tympani fibres with the ganglion now described.

Behind the hyomandibular trunk the facial ganglion thins down considerably, and is

seen to be perfectly spherical in transverse section. It is still visible, however, as a

thin cord containing ganglion cells as far back as the dorsal portion of the lateral line

ganglion. Behind this region it imperceptibly merges into the cephalic sympathetic

trunk which passes straight backwards and accompanies Jacobson's anastomosis, but, as

before stated, does not mingle with it. Opposite the glossopharyngeal ganglion the

sympathetic swells into a ganglion from which are given off some fibres whicii accompany

Jacobson's anastomosis to the glossopharyngeal ganglion. Behind the latter nerve the

connections between the sympathetic ganglia were very difficult to see *, although

the ganglia themselves were obvious at intervals as far back as my sections went.

J. Morphology of the Facial Ganglion.

I have hesitated considerably before committing myself to auy opinion as to the

nature of this interesting but most puzzling ganglion. When I first recognised it in

my sections, and saw that its cells were small and corresponded precisely to the cells

in the ciliary ganglion, with which I compared it, I concluded at once that it must be

the anterior sympathetic ganglion of the cephalic system described by the older

anatomists. When, however, subsequent investigation showed me its undoubted

connection with some of the fibres of the facial nerve, I was compelled to admit that it

might also belong to the trigemino-facial complex, and indeed represent a portion of

that complex which was in the act of migrating from its original position and becoming

converted into a typical sympathetic ganglion. In oi'der to avoid "settling" the

matter with an offhand suggestion, I delayed its further consideration until an

opportunity was afforded me of carefully working out the literature, a discussion of which

I now append.

Omitting the work of Cuvier (56, t. ii. pp. 512-515, 179',)), the first authors to

describe the sympathetic of Fishes were Desmoulius and Magendie (1825, 60), who traced

the cephalic sympathetic as far forwards as the " trigeminal " nerve, and were probably

the first to do this. Giltay followed in 1832 with a description of the sympathetic of

£so.v (By), which he found communicating with the vagus as well as with the

" trigeminus," and in 1831, in a general treatise on the structure and physiology of the

sympathetic of Fishes (88), describes the cephalic sympathetic of Gadus icglefinns. He

says (pp. 54-55) : '' Pars cejjhalica, continuatio trunci, eodem modo sese ab utroque

latere habet. Curvaturam sequitur partis basilaris ossis occipitis et ad vagum pervenit.

Nexus inter nervum sympathicum et nervum vagum mihi non lucide apparuit ; hoc

cert'um est, non cimn yanglio vagi direete conjungi ; sed contra nullum vidi ramum, cui

conjunctio tribui possit, quse tela cellulosa ahsolvi videtur. In mnliis speciminibns etiam

* Possibh" non-exisloiit at the .stage of my sections.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 137

frustra connuhium cum glossopharynyeo qucusivi, quamquam semper usque ad par qmntum

persequi potui n. symp., in citjus gangllo fiiiem Uahet." (Italics mine.) The statement

above re the vagus is of course eri-oneous, but it is interesting to note that Giltay did

not regard the facial (= a portion of his trigeminal) ganglion as belonging to the

sympathetic system. Tliis, however, was done by Biichner (1835, 36) in " Cyprinus

bnrhus'" { = Barbus i^ulyaris), who describes as the first sympathetic ganglion what is

undoubtedly my facial ganglion. Stannius (1842, 198) does the same for " Gadns

callarias," and also describes a sympathetic anastomosis with the glossopharyugeus,

whilst Bonsdorff (IStG, 30) goes stil! further, and not only considers the facial ganglion

to belong to the sympathetic system, but compares it with the otic ganglion of mammals —

a clever suggestion which should by no means be summarily rejected.

In his general ^^ork (1849, 199), Stannius largely recapitulates the results of his

former pajier, but adds very considerably to the information there given. He adheres

to his first interpretation, and further describes the anterior palatine as arising from the

facial ganglion, but failed to determine the relations of the posterior palatine and the

cephalic sympathetic. He was thus largely in agreement \\ ith his predecessors. Swan

(J864, 205) states that the cephalic sympathetic of the Cod is connected with the vagus,

glossopharyngeal, and " trigeminal " nerves, and figures these connections ; and Owen

(186G, 149, pp. 320-321), treating of the sympathetic of Tishes, says: "The first or

anterior couununication of this nerve, in tbe Cod, is with a branch of the fifth, and a

filament is sent forward to the ciliary gaiiylion .... Ganglions [/. e. sympathetic] are

sometimes found at the junction of the sympathetic toith the ffth, as well as at that with

the glossopharyngeal and with the vagus, before the great splanchnic is formed : small

ganglions are more rarely discernible at the junction of the sympathetic with the spinal

nerves." (Italics mine.) Baudelot (1883, 16) describes the first sympathetic ganglion of

tlie Perch as " applique au-dessous de la branche anterieure du trijuraeau," and

says that the cephalic sympathetic communicates behind witli the glossopharyugeus and

vams.

The two papers published by Gaskell in 1886 and 1889 (82 & 83) have great theoretical

importance, and I quite agree with Strong (204, p. 209) that " it is upon lines of work

approaching those of Gaskell that, in my opinion, the most fruitful results Avill be obtained."

Gaskell's studies were unfortunatelj confined principally to Mammals, which has necessarily

caused him to overlook several points and to make some errors. His methods have already

to a certain extent been applied to the lower Vertebrates by Strong and other American

zoolof'ists, and many important results have been obtained. In his first work Gaskell

emphasized the fact that besides the dorsal and ventral roots of a metameric nerve there

was also a morphologicjil third root — the visceral, sympathetic, or lateral root. The visceral

sensory fibres have a different origin from the motor fibres, the former probably arising in

the case of the posterior cranial nerves largely from the funiculus solitarius. Referring to

the distribution of the visceral nerves, Gaskell says (82, p. 11) : " From the upper cervical

re" ion they pass out [i. e. from the central nervous system] in a single stream to the

ganglia on the main stems of the vagus and glossopharyngeal nerves." Again, in the

section] " On the relation of the posterior root ganglia to the visceral nerves," be

138 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

remarks, p. 61 : '' 'llie ganglia of the main sympathetic chain must, according to Onodi,.

be considered as offshoots (Abkommlinge) of the posterior root gangh'a. If this is so, we

may conceive tliat the posterior root ganglion in the thoracic region may be dovible, part

belonging to the somatic, part to the splanchnic root. Remak described the origin of

nou-meduUated fibres from the posterior root ganglion as well as from the sympathetic

ganglia .... The connection of the fibres of the ramus visceralis with the cells of the

ganglion on the posterior roots of the thoracic nerves is most clearly visible in the case

of the tortoise. In this animal the ramus visceralis does not spring from the ventral

branch of the spinal nerve as in Mammalia, but arises directly from the ganglion on the

posterior root." I extract the following from the section in Gaskell's second paper

(p. 162), containing a definition of a complete segmental nerve : " Turning our attention

now to the arrangement of the fibres composing a complete segmental spinal nerve, the

results arrived at in my previous paper show that we must look upon both afferent and

efferent roots as ganglionated, for the whole argument in my former paper as to the

meaning of the sympathetic system was to prove that the symjwthctic ganglia are the

ganglia helonging mainly to the fine meduUated fibres of the anterior roots, so that we

must look upon a spinal nerve as possessing efferent or motor ganglia as well as aflfereot

or sensory ganglia. These efi'erent ganglia have, according to the observations of Onodi,

travelled away firom the original ganglionic mass situated on the roots of the spinal nerve,

so that we may term these motor ganglia ' vagrant ' in contradistinction to the ' stationary '

sensory ganglia on the posterior root ; it follows then that a spinal nerve must be defined

as formed by (1) A posterior root composed of aflFerent fibres, both somatic and splanchnic,

the ganglion of which root is stationary in position and is always situated near the

entrance of the fibres into the central nervous system " (Italics mine.) On p. 174

Gaskell states his belief that the facial nerve of mammals " has lost its primitive stationary

ganglion and the afferent fibres in connection with that ganglion ; I would therefore look

upon the existing sensory distribution of the nerve [cp. particularly p. 173] as belonging

to the same system as that of the Vth : i. e., as already mentioned, a system of sensory

nerves which has taken the place of the lost sensory elements of the primitive group of

segmental nerves." I shall give, further on, reasons for doubting Gaskell's latter

statements.

In 1890 an important work was published by Chevrel (1887-90, 41) on the sympa-

thetic nervous system of Fishes. This author states tliat in the bony fishes the first

sympathetic ganglion is always associated ivith the "trigeminus" and lies under the

Gasserian ganglion. The second sympathetic ganglion is described as follows (p. 179) : —

" Le 2" ganglion cephaliqne est place sous le facial ou en arriere de ce nerf qui lui envoie

ses racines. II emet tin ou deux filets pour le facial et ses ramifications ; il en emet

tonjours un autre pour le rameau anterieur du glossopharyngien." (Italics author's.) It

seems from these quotations that the facial ganglion of the Cod may represent Clievrel's

first and second ganglia fused. In the Physostomi Cheviel makes the remarkable and

interesting statement that the visceral branches of the vagus are all connected with the

first sympathetic ganglion, which in the case of these fishes is attached to the vagus and

not to the trigeminus.

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 130

Shore, in 1889, applying Gaskell's methods to the fishes, arrives at some noteworthy

results. He states tliat the vagus is mostly composed of the visceral elements of the

anterior spinal nerves rather than a compound of several complete metameric nerves, as

Gegenbanr maintained in his memorable Rexanclnts * paper. Shore discovered on the

dorsal branch of the vagus a small ganglion which he homologises with a doi-sal root or

" somatic sensory" ganglion f- At the most, however, it can only represent a portion of

this ganglion. The branchial (= post-branchial) ganglia ai-e considered to represent the

vertebral or vagrant ganglia of the syrapathethic trunk, and the proe-branchial ganglia

(first described by Shore) the proe-vertebral or collateral ganglia of the sympathetic

system. The latter statement will be discussed later on, but I may mention now that

Shore admits the fibres which join the prse-branchial ganglia should be non-meduUate,

which the prae-branchial fibres are not. Omitting the dorsal branch and its ganglion, the

vagus, according to Shore, contains the sympathetic elements only of a spinal nerve, and

not its somatic elements. He further states that the post-branchial nerve contains some

splanchnic sensory fibres, and believes finally with Habrecht that the lateralis lateral line

nerve is equivalent to the lateral strands of the Nemertea — a conclusion which our

knowledge of the lateralis nerve enables us absolutely to disprove.

Ayers (1892, 7), referring to the -chorda tympani of Mammals, a subject which we

shall see later on interests us in this connection, says (pp. 312-313) : — " As is well known,

the sensory fibres subserving the sense of taste in the anterior two-thirds of the tongue

run through the chorda tympani, and the recent investigations of Sajiolini make it fairly

certain that the chorda tympani is a continuation of at least a portion of the fibres of the

portio intermedia Wrisbergi, which pass through the ganglion genicali to the chorda

tympani."

Ewart (1893, 70), after referring to the small size of the cells in the ciliary ganglion

(see, re size of cells in facial ganglion, below), says, in. describing the palatinus facialis of

Elasmobranchs, that it " dips downwards and In-eaks up into numerous branches, which

end in the mucous membrane of the roof of the mouth. At the root of this trunk there

are always numerous ganglion cells. Sometimes these cells are continuous with the cells

at the root of the facial trunk ; but in others they extend a short distance into the root

of the palatine, and are completely, or all but completely, separated from the ganglion of

the facial trunk. I have no hesitation in saying that the palatine nerve of the skate

corresponds, as has been suggested by Gegenbaur and othei's, to the great superficial

petrosal of the mammal, and that further enquiries are likely to show that the ganglion

at the root or in the trunk of the palatine nerve corresponds to the spheno-palatine

(Meckel's) ganglion of the mammal. Or, to put it another way, were a spheno-

palatine ganglion developed in the skate, it would be derived from the cells (or some of

* Cp. Minot (140, pp. 650-651). Whether formed of complete metameric nerves or not I do net propose to

discuss, but that the vagus is a compound nerve is not a " bold hypothesis " but an anatomical fact, lack of

embryological evidence notwithstanding.

t An omission in my Chimcera paper (46) may be corrected here. On p. 671, line 15, for " is in connection,'' read

" is also in connection.''

SECOND SERIES. — ZOOLOGY, VOL. VII. 20

140 ME. P. J. COLE OX THE STEUCTUEE AND MOEPHOLOGY OF

them) lying in the root of the palatine trunk." In my Chhncera paper I was inclined to

doubt the separate existence of the palatine cells described by Ewart, and considered

them part of the geniculate ganglion — in which is seen the evil of basing general con-

clusions on a special study. It is now obvious to me that these cells form a perfectly

distinct prsB-branchial ganglion, comparable to the facial ganglion of the Codfish. We

have seen that BonsdorfF compared the latter to the otic ganglion, and Ewart now

compares it to the spheno-palatine ganglion. Both conclusions are erroneous, although

both come somewhat near the truth. There is less objection to the splieno-palatine than

to the otic ganglion, since the former is apparently more distinctively connected with the

facial nerve than tlie latter. Both ganglia are essentially vagrant and largely motor,

and hence cannot correspond either to the facial ganglion of the Cod or Evvart's palatine

cells in Elasmobranchs. But Dixon's work (6i) conclusively settles the matter. He

shows that both ganglia are developed in connection with brandies of the trigeminal

nerve, and only become secondarily connected late in development with the facial. They

cannot therefore correspond to a ganglion belonging essentially to the facialis. Before

leaving Ewart's work I should like to quote a passage on p. 3 which has some bearings

on the jDresent issue. He says : — " In the skate there is but a single ganglionic swelling

on the root of the glossopharyngeal, but this swelling contains two kinds of cells. The

dorsal part from which the dorsal branch springs consists of large cells, loMle the deeper

part, from which the fibres of the pharyngeal branch proceed, consists of small cells''

(Italics mine.)

The important work piil)lished by Strong (1895, 204) helps us very considerably in

clearing up the morphology of the facial ganglion of the Cod. In all Eishes and Amphi-

bians there is an important system of fil)res entering into the composition of the Vllth,

IXth, and Xth cranial nerves, to which Osboi-n (147) devoted considerable attention, and

which was called by him the fasciculus conimunis system. These fibres were carefully

investigated and grouped by Strong, who showed (1) that they had a distinctive origin in

the brain; (2) that they formed- the palatine or visceral and prm-branchial (=^Ghorda

tympani in- case of facial) divisions of the branchial nerves; and (3) that they were gan-

glionated. It hence follows (1) that the prae-branchial ganglia described by Shore and Ewart

are simply the ganglia on the fasciculus communis fibres; and (2) that the prce-branchial

fibres have a different internal origin in the brain than the post-branchial fibres. As to

the nature of the fasciculus communis tract, Strong says (p. 182) that it is " composed

exclusively, or almost exclusively, of visceral (splanchnic) fibres innervating the ali-

mentary canal and its appendages " (italics mine), and considers that it is " mainly sensory ''

in function. Other important conclusions arrived at by Strong, after careful investi-

gation and consideration of the literature, are (1) that the fasciculios communis corresponds

ioith the mammalian fasciculus solitarius in every detail ; (2) that " as the fasciculus soli-

tarius is continued cej)halad into the portio intermedia, it is evident that the portio intern-

media is represented ui the tadpole by the fasciculus communis root of the Vllth, the

ganglion geniculi by the ganglion of this root, fused in the tadpole with the ganglion Gasseri.

l)ut separate in Amblystoma, and the chorda tympani by the portion of the fasciculus

THE CEANJAL NEEVE8 AND LATEEAL SENSE OEGANS OF FISHES. 141

communis which, on emerging from its ganglion, unites with hyomandibularis VII.,

separates as the R. mandibularis internus *, and innervates portions of the floor of tlic

pliarynx, especially the part in tlie tadpole near the site of the future tongue" (p. 186) ;

and (3) that the R. palatinus facialis corresponds to the great superficial petrosal t, tJie

latter being a visceral sensory and not a visceral motor nerve (cp. Turner, Jouru. i\.uat. &

Phys. vol. xxiii. p. 523, 1889).

Kingsbury (1895, 113, and 1897, 114) states that the fasciculus communis system

arises from tliu dorsal columns of the medulla and tliat it is largely sensory in function,

whilst Allis (1897, 6) must be held to have completely established that the palatine and

prse-branchial fibres of the branchial nerves are composed of visceral sensory fibres and

the post-branchial nerves of visceral motor fibres. This is also borne out l\v his dissec-

tions and descriptions of the facial, glossopharyngeal, and vagus nerves, where the

fasciculus commimis fibres were traced on to the mucous memlirane % and the post-

branchial fibres into the branchial muscles. On p. 611, after a lengthy discussion of the

fasciculus communis system, he says : — " The fibres of the fasciculus communis tract thus

seem destined to form m part or in whole the prae-trematic and pharyngeal branches of the

nerves wdth which they are associated, and it is always in the regions which, whether on

the outside or the inside of the body, are, from tlieir relation to these nerves, presum-

ably innervated by them, that terminal buds are found. The fibres of the tract that join

and form -part of the facialis enter into, or form entirelij, the inferior and superior

branches of the i)alatinus facialis, and those two branches are respecticely the pretrematic

and pharyngeal branches of the nervus." (Italics mine.) On p. 012, after stating that he

considers it probable the terminal biuU arise in connection with the pretrematic rjanglia

and ectodermal thickenings, he concludes, "in short, the nerve fibres arising from tlie

fasciculus communis tract seem destined in large part, if not in whole, to the supply of

terminal buds, as Strong has suggested might be the case. The fibres so arising may

issue from the brain as a separate and distinct root, on which a separate and distinct

ganglion is found; they may issue in part as components of certain nerves with the

roots of those nerves, and in part as a separate root which becomes immediately more or

less fused, it and its ganglion, with other roots and ganglia ; or they may apparently,

issue entirely as components of certain nerves. To the fii'st category belongs, apparently

Protopterus ; to the second, yiw/r/, i2«;^«, and many other fishes and amphibia; to the

thii'd, birds, judging from Brandis' descriptions, for he finds the fibres of the

funiculus solitarius issuing from the facialis and glossopharyngeus, and possibly also

with the vagus, and the funiculus solitarius of higher vertebrates corresponds, according

to Strong, in every detail icith the fasciculus communis of fishes and amphibia" (Italics

mine.) Two points I must emphasize in connection with Allis's conclusions. Pirst, he

* 1 have already shown (46, pp. (558 & C73-4) that this is a misnomer. See also later, p. 200.

t Cp. 46, p. G60. See also later, p. 144.

i In his general summary he says (p. 747) : — " The ramus pharyngeus and ramus pra^trematicus traverse regions

where terminal huds are found." (Italics mine.)

20*

142 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

appears to consider that the fasciculus communis system is in part somatic as well as

splanchnic, which is inadmissible in the present state of our knowledge* (but see p. 175) ;

second, as Kingsbury (1897, 114) ^^^ pointed out (p. 29), the system is not entirely

coufiued to the iuuervation of terminal buds. With regard to the first objection, it is of

course difficult, if not impossible, in the region of the visceral clefts, to determine where

the somatic region ends aud the splanchnic begins. As Allis apparently considers that

the terminal buds of the mouth were originally on the surface (and therefore somatic

sensory), aud have since wandered on to the gill arclies and visceral surfaces, he must

hold the visceral character of this portion of the fasciculus communis system to have

been secondarily acquired.

Max Fiirbringer (1897, 79) t, in commenting on the connections between the occipital

nerves and the true cranial nerves, says (p. 5G8) : — " Die Anastomosen mit dem Sympa-

thictis dao-eo-en reprascntiren zu einem grossen Theile wirkliche Wurzeln desselben (Br.

viscerales) und sind insofcrn von Interesse, als sie den Beweis fur die immer noch von

Einzelnen bezweifelte Thatsache erbringen, dass sympathische Fasern und Ganglien

auch den ventralen Spinalnervenwurzeln entstauunen." In a footnote Fiirbringer draws

attention to a statement by Van Wijhe of the existence of sympathetic ganglia on the

ventral roots of the posterior cranial nerves of ScylUum embryos. Finally, Herrick

(1897, 9S) states that the fasciculus communis system innervates taste buds and other

specialised sense organs (other than the lateral sense organs) and the visceral surfaces in

treueral, and on p. 428 says that the palatinus facialis consists of " fasciculus communis

fibres from the geniculate ganglion distributed exclusively to the taste buds of the mouth."

The above consideration of the literature makes the solution of the problem a some-

what easy matter, and we may at once draw up the following general conclusions : —

(1) The facial ganglion of the Cod is precisely comparable in every respect to a prse-

branchial or prse-trematic ganglion, since it is the ganglion of the palatine and

chorda tymiiani nerves which consist of fibres belonging to the fasciculus

communis system.

(2) It is hence physiologically and morphologically comparable to a sympathetic ganglion,

since the fasciculus communis fibres belong essentially to the sympathetic system

and innervate the visceral surfaces.

(3) The ganglion has been well known to anatomists for a long time, and was considered

by most of the older zoologists to be the most anterior sympathetic ganglion, and

to exist only in the osseous fishes. It was rediscovered in Elasmobranchs by Shore

and Ewart, and fui'ther described by Allis and Strong (Amphibia) ; but these

authors failed to homologise it with the ganglion in the osseous fishes, and refer

* I am aware of certain statements of Ramsay, "Wright, Kingsbury, aud Herrick to the contrary, but tliink the

bulk of the evidence goes to show that the fasciculus communis fibres belong to the visceral system. In any case,

however, my argument is unaffected, since the fasciculus communis fibres in the palatine and prai-branchial nerves

are'admittedly visceral ssnsory.

t Ttam indebted to the generosity of the author for a copy of this fine work.

THE CEANIAL KERA-JuS AND LATEEAL SENSE OEGANS OE EISHES. 143

to it variously as the prtE-branchial, prse-trematic, palatine, or fasniculus communis

ganglion (in part). Some of the older anatomists regarded it as belonging to the

trigemino-facial complex, and others described more than one ganglion in this

region in Teleosts.

(4) We have seen that tlie facial ganglion is a ganglion placed on fibres that un-

doubtedly belong to the seventh or facial cranial nerve. It seems therefore to

belong to the trigemino-facial complex, and cannot, in face of this fact, be

considered a purely sympathetic ganglion. But we have further seen that it has

many sympathetic characters, for in the first place it is connected with the fibres

of the fasciculus communis system which we know to be essentially sympathetic

in character ; in the second, its cells are small, and correspond to the cells found in

the ciliary and true sympathetic gnnglia; and in the third, it gives origin to the

cephalic sympathetic trunk. It cannot, by the very nature of its structure and

connections, correspond to a prc-vertebral ganglion, as Shore has suggested (and,

indeed, Shore himself advances a very good reason against this), nor can it

represent a typical vagrant ganglion, since these are connected with, visceral

motor fibres. The only alternative left is that it represents the visceral portion of

a dorsal root ganglion, since the latter is partly in connection with visceral sensory

fibres. And this I believe to be the case. How, then, is its isolated position to be

explained? We know from Gaskell's classic researches on the sympathetic

nervous system, for which every vertebrate morphologist is grateful to him, that

the splanchnic ganglia on the main trunk of the sympathetic system, or " vagrant "

ganglia as he calls them, are in reality ganglia belonging to the roots of the meta-

meric nerves which have wandered from their original position. May not the facial

ganglion of the Cod be in an intermediate condition ? Here we have a ganglion

of which the structural relations are such that it defies classification — it can

neither be classified as a cranial nerve ganglion nor as a typical sympathetic

ganglion, unless indeed we disassociate the fasciculus communis system from the

cranial nerves altogether and add it to the sympathetic. In the Elasmobranch

fishes, which we know from pakeontology represent a more primitive condition

than the Teleosts, the pre-spiracular ganglion (=facial of Cod) is still in very close

association with the main facial ganglion. In the specialised Teleosts, on the

other hand, the ganglion is found to be completely separate from the trigemino-

facial complex. We are therefore forced to the conclusion that the facial ganglion

of Teleosts is in the act of doing what ^\■e know the visceral motor ganglion to

have done, i. e. is migrating from its original position, and will perhaps become

in the course of time a typical sympathetic ganglion. In short the facial ganglion

of the Cod is an exemplification of the principle of evolution, and shows us a

stationary ganglion l;ecoming converted into a vagrant or true sympathetic

ganglion.

144 MR. F. J. COLE ON THE STEUCTURE AND MORPHOLOGY OF

We may hence classify a typical bi-anchial nerve as follows : —

I have already here and there referred to the facial nerve of man and mammals,

the morphology of which may be treated of here. In my Chimcera paper I pointed out

(46, p. 6C0) that the general anatomy of the facial nerve in man was in close agreement

with the same nerve in the lower vertebrates. A more careful enquiry into the facts

confirms this somewhat remarkable conclusion even in many of the details.

The facial nerve of man and mammals may be divided into two parts, which may be

held to correspond to the same parts in the branchial facial nerve of fishes. These parts

are (1) a pre-branchial part, largely or in part visceral sensory, =the nervus intermedins

or pars or portio intermedia of Wrisberg, comprising the geniculate ganglion, great

superficial petrosal (palatine), and chorda tympani (prae-branchial) ; and (2) a post-

branchial part, comprising the main trunk of the facial, and being at least partly a

visceral motor nerve *. The points of agreement between the facial nerve of the fish

and mammal are as follows : —

(1) In central origin. It is probable that the fibres of the nervus intermedins arise from

the funiculus solitarius, which is a centre of visceral sensory fibres, and which, as

Strong has shown, corresponds precisely to the origin of the fasciculus communis

of fishes and amphibia.

(2) In the nature of the fibres. The fibres of the nervtis intermedins are " very small,"

and hence correspond to the fasciculus communis fibres. Further, they are

mainly visceral sensory in function, and are certainly continued in part into the

chorda tympani, and perhaps also into the great superficial petrosal. The visceral

motor fibres of the facial trimk are represented at least by the fibres supplying

the stapedius muscle and those muscles of the " hyoid " develojied in connection

with the second visceral arch.

(3) The geniculate ganglion is a stationary ganglion mainly in connection with visceral

sensory fibres of the nervus intermedins. It hence corresponds to the facial ganglion

of the Cod and to the pre-spiracular or palatine ganglion of Elasmobranch fishes.

* See Wiedersheim (lt^97, 221), where the relations of these nerves are well shown (p. 183),

THE CEAjSIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 145

Now to endeavour to show that the facial nerves of fishes and mammals resemble each

other in every minute detail would be to prove far too much. Differences are to be

expected, and they certainly exist. The most striking difference is in the existence of a

large somatic motor component in the mammalian facial. Assuming that the facial

muscles of mammals cannot be derived from visceral arch muscles, upon which I am

not competent to offer an opinion, we must regard tliis component as a special develop-

ment and characteristic of tlie higher vertebrates. The difficulty re the motor character

of the great superficial petrosal has already been alluded to, and a still farther difficulty

with regard to this nerve lies in Lenbossek's contention that its fibres are not connected

with the cells of the geniculate ganglion. The chorda tympani too, and with it neces-

sarily the nervus intermedins, is supjjosed to be partly motor. The absence of a visceral

motor ganglion corresponding to tlie post-branchial ganglion of the fish is noteworthy,

but it is perhaps represented by the degenerate ganglion described by Gaskell. This is

indeed what we should expect, in view of the reduced condition of tl\e hyoid arch and

its muscles.

We thus see that even if the facial nerve of mammals does not correspond detail for

detail with the same nerve in lower vertebrates, which is indeed not to be expected or

desired, there is yet a sufficient general resemblance between the two to show that they

are genetically related. The mammalian facial, in short, bears in its present-day structure

undoubted evidence of its descent from the branchial facial nerve of a fish.

K. Morphology of Jacobson's Anastomosis.

The morphology of Jacobson's anastomosis, of which I have a new explanation to

offer, may be treated of here in connection with the trigemino-facial ganglionic complex,

with which I have described it. This anastomosis is essentially a connection between

the facial and glossopharyngeal nerves, and, as I shall show, is perfectly homologous in

the highest as well as in the lowest vertebrates, and is further a branch of the glosso-

pharyngeus which accompanies a branch of the fa(nal.

Jacobson's anastomosis was first identified in the lower vertebrates by Stannius * in

1842 (198). He found it in " Gadiis callarUis " { = G. inorrhua) and described it under

the name of the " H. anterior s. gustatorlus.'" The correct explanation of the nerve, that

it is in the first place a branch of the Xlth and not of the Vllth nerve, and in the

second the joalatine or visceral branch of the IXth, may be deduced even from Stannius's

description and figures. Bonsdorff (1S46, 30) confuses Jacobson's anastomosis with

the sympathetic, but Jackson and Clarke (1876, 106) correctly consider it to be the

pharyngeal division of the glossopharyngeus. Van AVijhe (1882, 222) describes it in

Acipenser (p. 237) in almost the same condition as it is in the Cod and Amia, i. e. as

connecting the glossopharyngeus with the palatine division of tlie facial. An important

and interesting difference, however, is that it jmsses further forwards still and becomes

* In his later work (1840, 199) he describes the palatinus facialis as being oocasionall}' reinforced by the palatinus

glossopharyngei.

146 MK. r. J. COLE ON THE STUUCTUliE AND ]MORPHOLOGY OF

connected with the "palatine" division of the trigeminus. Goronowitsch (1888, 89)

largely confirms Van Wijhe. He mentions a lateral line anastomosis l)etween the vagal

and facial groups, as in Protopterus, and also a true Jacohson's anastomosis between the

palatine divisions of the Vlltli and IXth, as in Amia and Gadus.

Pollard (1892, 160) correctly homologlses Jacohson's anastomosis in a table printed on

p. 398, and sliows in Taf. xxvii., fig. 7, a somewhat similar condition to that described in

Amia by Allis. The anastomosis is, however, continued forwards and unites also with

the trigeminus. There is no description or mention of the nerve in the text. The

anastomosis therefore in Polypterus agrees with the condition found in Acipenser

by Van Wijhe. In the fine work by Pinkus (1894, 157) on Protopterus anneclem a

lateral line anastomosis is described (outside the auditory capsule) connecting the root

and ganglion of the lateralis lateral line nerve with the common root of the superficial

ophthalmic and buccal lateral line nerves (cp. Goronowitsch). Jacohson's anastomosis i»

in much the same condition as in Gadus and Amia. The palatine branch of the IXth as

it passes forwards sends an anastomosing branch to the visceral or palatine branch of the

facial. There is no connection with the trigeminus.

The anastomosis in Puna between the Vlllh and the IXth is apparently of a different

nature, though it also properly belongs to the IXth. Strong (1895, 204) says (p. 146) : —

" The other inner division of mixed fibres is the P. communicans ad facialem to the

R. hyomandibularis. Its final distribution is described in connection with the latter,

anU it lias there been found to be a general cutaneous nerve." (Italics mine.) The fact

that the nerve in Pana consists of somatic sensory fibres makes it impossihle to

homologise it with a true Jacohson's anastomosis. Strong, however, seems to have had

an inkling of the truth, for he remarks (p. 207) : " Furthermore, among the Fishes, the

palatine nerve would appear to be formed by a union of post- and pre-auditory nerves-

(Goronowitsch, Pollard). The development of the auditory organ has probably caused a

separation of nerves formerly more closely connected."

In man the tympanic branch of the glossopharyngeal, or nerve of Jacobson, un-

doubtedly corresponds to the nerve called after it in the lower vertebrates. Its origin

from the petrosal ganglion, which seems to me to be morphologically comparable to the

" facial " or geniculate ganglion — that is, in connection with splanchnic sensory fibres —

at once suggests this. Unfortunately the composition of the tympanic nerve is, I believe,

not known in man. Its connection with the facial is partly by means of a small branch

which passes into the geniculate ganglion. This branch at least must be splanchnic

sensory, and is thus of the same constitution as Jacohson's anastomosis of the fish.

Its continuation, however, the small superficial petrosal nerve, is usually regarded as a

splanchnic motor nerve. Jacohson's anastomosis in man, therefore, seems to resemble

the same nerve of the fish in every essential detail. The exception, that it does not

directly anastomose with the great superficial petrosal ( = the palatinus facialis), is of

course of no morphological importance*. Dixon (1896, 61) has conclusively proved,

if such proof were wanting, that the nerve of Jacobson belongs to the glossopharyngeaL

* App.'ircntly it docs so in tbo embryo. Cp. Dixon, p. 63.°

THE CEAxXIAL NEliVES AND LATERAL SENSE ORGANS OF FISHES. 147

He says (p. 58) : " The nerve of Jacobson is present in this embryo, as an outgrowth

from the petrous ganglion of the glossopharyngeal, but is very short. This nerve passes

vertically upwards, and ends a considerable distance below the level of the inferior

maxillary nerve." Dixon also states (p. 66) that the nerve of Jacobson grows out from

the petrous ganglion in the rat.

Jacobson's anastomosis is described in ^iv/^iV by Allis as follows (6, pp. 685-686): —

" In the palatine canal the ramus pharyngeus lies on the median side of the ramus

palatinus facialis, and at the point where that nerve separates into its anterior and

posterior branches the pharyngeus, in one dissection, separated also into two portions,

one qfioJiich accompanied each of the tico branches of the palatinus [facialis]. In other

dissections this separation was not evident, tlie pharyngeus glossopharyngei accompanying

the anterior branch of the facialis and issuing on the ventral surface of the vomer to be

distributed to dermal tissues there." (Italics mine.) This description hardly tallies with

plate xxxviii., where a complete anastomosis with the palatinus facialis is tigured. Allis

does not homologise it with Jacobson's anastomosis, but it is obvious that this is what

it is, seeing that it is formed by the visceral branch of the IXth accompanying the

corresponding division of the facial.

Huge (1897, 169), after referjing to anastomoses described by Stannius [Acipenser,

Perca, Tinea), Johannes Mliller [Tolijpterus, Lepidosteiis), and Eischer [Blenobranchus,

Siren), concludes with reference to the mammalian tympanic nerve : — " Es besteht aber

ausserdem die Moglichkeit, dass in der rortsetziing des N. tympanicus das llomologon

des Ramus pharyngeus (IX.) enthalten sei. 1st dies der Fall, so entspricht der N. petrosus

superficialis minor sowohl deni N. palatinus als audi einem der Jxv. branchiales n. vagi

der Fische. Die Anastomose, welche zwischen Facialis und Gl.-phar. ganz ausserhalb

des Schadels besteht, darf ndt der erwahnten nicht verwechselt werden. Sie ist sehr

wahrscheinlich dvirch die Verschmelzung der motorischen Endgebiete beider Nerven

(;ntstauden " (p. 213). Finally, fig. 118, p. 182, in tlie new English edition of Wiedersheim's

' Comparative Anatomy ' (1897, 221), for the accuracy of which I am partly responsible,

should be corrected in two respects : (1) tlie dotted pharyngeal branch should be deleted,

and so also should the nerv e labelled Jak. (Jacobson's anastomosis). The latter, we have

seen, is represented by the palatinus glossophai-yugei.

It is hence clear that thiee nerves have been described connecting the vagal and facial

o-roups of cranial nerves, each of which has a distinctive composition. These are : —

(1) A somatic sensory anastomosis. Described by Strong in Amphibia. This is the

only instance known, I believe, of an anastomosis of this nature. It is possible that

Strong may have been mistaken as to its character, especially as it, too, is distinctively a

branch of the glossopharyngeal ; but however that may be it cannot be considered

comparable to a true Jacobson's anastomosis.

(2) A lateral line anastomosis. This more usually connects the facial with the vagus,

but where a portion of the lateralis lateral line nerve accompanies the glossopharyngeus,

it may connect that nerve with the lacial. The character of this nerve cannot be mistaken,

since it usually exists side by side with Jacobson's anastomosis.

(3) A visceral sensory or true Jacobson^s anastomosis. That the nerve which usually

SECOND SEIUES. — ZOOLOGY, VOL. VII. 21

l^iS ME. F. J. COLE ON THE .STEUCTUEE AND MOEPllOLOGY OF

connects the Vllth and IXtli nerves is homologous throughout the different classes of

vertebrates there can be little doubt. It is further certain that this nerve is a branch

of the glossopharyngeal, is primarily quite distinct from the facial, and in the adult

only accompanies a branch of the latter nerve. It is the main body of the first, visceral,

palatine, or pharyngeal branch of the IXtli, and as sucli, in the lower vertebrates at any

rate, belongs to the fasciculus communis system, and consists very largely, if not entirely,

of visceral sensory fibres. It passes forwards, and, as a general rule, becomes related to

the palatinus facialis, and either accompanies the main trunk of the latter or some of

its branches, or it may completely fuse with it. It is hence usually not an anastomosis

at all, in the sense that an anastomosis should l)e a perfect mingling of two nerves.

Its forward continuation to the trigeminus, described by Van Wijhe and Pollard, I am

inclined to view with some doubt, and await further details on the point. The difficulty

in the case of the trigeminus is that the visceral sensory branch is typically unrepresented

in this nerve (cp. Goronowitsch, 1888, 89), and the anastomosis could not, therefore, as

Van Wijhe describes, be connected with its " palatine " branch. The explanation of an

anastomosis at all is to be sought for in the fact that both nerves concerned have a

similar peripheral distribution, and may hence fitly accompany one another. The

interpolation of the auditory organ has doubtless assisted in further separating the

nerves, and thus converting a simple fact into a phenomenon.

L. The Metamekism of the Lateral line System.

A description of the nerves supplying the lateral sense organs would naturally follow

the descri2)tion and discussion of the trigemino-facial ganglion and Jacobson's

anastomosis, but it is obvious, however, that before this can be attempted it is expedient

to enquire into the morphological value of these nerves, to determine to which of the

cranial nerves, if any, they belong, and in fact to consider the whole question of the

metamerism of the lateral sense organs. The structure and development of the lateral

sense organs show conclusively that they were originally confined to the head, and have

only secondarily been continued on to the trunk. How did they arise ? Are they

segmental at all, and if so is the segmentation primitive or acquired ? It is perhaps

unnecessary for me to point out that these questions can only be solved satisfactorily by

determining the morphology of the nerves supplying them. It is indeed true that the

position of the organs themselves and the relation they have to the dermal bones of

the skull may in some Avay help us, but their position and structural relations are too

variable, and tlieir significance too equivocal, to have anything more than confirmatory

importance attached to them. We thus have to review the facts of development and

adult structure and to ascertain in what direction modern research is leading us.

Eisig (18S7, 65), whose work will also be discussed elsewhere, naturally considers the

lateral line organs metameric, and in fact goes so far as to consider the probability of

their being once connected with spinal nerves. This he endeavours to establish by

referring to the Avork of Julin and Ransom and Thompson on the Lamprey. These

authors, however, were dealing with the so-called lateralis nerve of Petromyzon, and as I

shall show later on that this is 7iot a lateral line nerve at all, Eisig's contentious must

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 1 L9

consequently fall to tlie ground. Van Wijhe (1882, 222) was perhaps the first to draw

attention to the undoubted metamerism of the lateral line organs on the body in some

forms, and points out that each lateral line scale in Amia corresponds to a segment of

the body. He is inclined to think that some such relation may l)e found to exist between

the lateral line ossicles and the segments of the head. Beard (188 f, 17), as tlie title of

his paper implies, advocates the metamerism of the lateral sense organs, wdiilst Ramsay

Wright (1884, 227) finds that in Amiurus the sense organs of the body are n^etamerie,

and correspond exactly to the number of spinal nerves.

The papers of Froriep and Beard (1885, 19) are of considerable importance, since it is

upon the evidence of these authors and others follf)wing them that the plea for the

metamerism of the lateral sense organs is very largely based. It must be pointed out at

the outset that the " brancliial " or " epihranchial " sense organs are only doubtfully

metameric, and several authors have commented on Beard's significant alteration of the

name from " segmental " to " branchial." The whole question depends on the metameric

value of the visceral clefts, but at any rate the bulk of the evidence goes to show, and

for the purposes of the present discussion we may admit, that if the branchial sense

organs are not now metameric there is strong reason for loelieving that they were so in

past time. The innervation of these very interesting sense-organs is, according to Beard,

from seven dorsal branches or supra-branchial nerves. These are : — (1) Ophthalmicus

profundus ; (2) superficial oijhtluvlniic of the Vth ; (3) superficial ophthalmic " of tlie

Vllth " ; (1) the buccal division " of the Vllth " ; (5) the dorsal or supra-temjjoral branch

of the IXth ; (6) the dorsal or supra-temporal ])ranch of the first division of the Xth ;

(7) the lateralis nerve of the remainder of the Xth. There can be no doubt that, should

this evidence prove trustworthy, we have very strong reasons for regarding the lateral

sense organs as metameric structures, since the latter are supposed to be formed by the

growth and extension of the branchial sense organs.

Allis (1889, 4), without definitely committing himself to an opinion, is undoubtedly

favourable to the metamerism of the lateral organs, even if we only call to mind his

statement that they are innervated by the dorsal branches of two cranial nerves — the

facial and the vagus. On pp. 517-518 he destroys one of Beard's supra-branchial

nerves, and points out that the supra-branchial nerve from the first vagus ganglion is in

Amia " the first dorsal or supra-temporcil branch of the latenxl nerve,"' and hence has ni>

metameric significance. On p. 523, referring to Van Wij he's views above, he remarks : —

"The arrangement of the sense organs and nerves of the lateral system, the regular

occurrence of primary tubes between consecutive dermal bones of the head, as well as

between consecutive scales of the lateral line, and the singular correspondence between

the infra-orbital and opercular canals is further evidence in this same direction "

[*. e. of metamerism]. I am not inclined, however, to attach much weight to these

considerations. In the first place, there are too many exceptions to the regular occur-

rence of the primary pores between consecutive dermal bones for this consideration to

have much value *, and in the second place, although in the case of the Cod there is a

* Allis says (p. 537) : — " Although some of the prima'')' tubes issue through the bone, one always issues between

every two cousecutive bones along each liuo."

21*

150 MK. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

certain correspondence between the infra -orbital and byomandibular lateral canals, it

does not occur, as far as I am aware, in any other iish. And surely, in any case, the

corresjiondeuce has absolutely no significance. The byomandibular canal is situated on

a region morphologicaUi/ posterioi' to the infra-orbital canal, and cannot belong to the

same segments or segment of the head. If the correspondence had been l)etween the

supra- and infra-orbital canals (and these do not correspond either in Ainia, Gadus, or

any other fish that I know of), it might have had some significance, although, I am

inclined to think, very little.

An interesting addition to the developmental litei-ature was made in 1891 by Wilson

{225), who was the first, I believe, to discover tliat the lateral line organs and auditory

organ may arise from a common sensory anlage. This seems to be oj)posed to the

metameric view, bnt Wilson himself believes it to be a physiological adaptation and to

have no phylogenetic significance. He favours Beard's views with regard to the head,

but does not think the lateral organs of the body were primitively segmental.

Cunningham (1890, 55) draws attention to the fact (p. 75) that in the Sole, " corresponding

to eacli scale of the lateral line, there is a pore in the skin which leads into the dermal

tube of the lateral line." On p. 81, however, he says : — " There is not a sense organ to

every scale of the lateral line ; in the middle of the body there is a sense organ on every

third scale : that is to say, there are two scales bearing no sense organs between two scales

which bear them. The position of the sense organ in relation to the scale on which it

is situated is always the same." Fig. 6, pi. xiv., shows this somewhat anomalous

condition. Without impugning the accuracy of Cunningham's statement, I may point

out that it is a remarkable exception to the almost universal law that there should

always be at least one sense organ between the openings of two dermal tubules *.

Mitrophanow (1890, 141) confirms Wilson's statement re the common anlage of the

lateral line and auditory systems, and in 1892 (142) disagrees with Wilson and states his

belief that the lateral organs are not metameric. In a full paper published in 1893 (143)

Mitrophanow repeats his former statements, Imt adds that tlie common anlage gives rise

to the auditory organ, the lateral line organs, and Beard's branchial sense organs. He

considers this suflB.cient ground for maintaining that the lateral organs were not primi-

tively metameric, and says this conclusion is based on the study of all the Ichthyopsid

types he has investigated. Houssay (1891, 103), in an interesting review of Mitrophanow's

second work above, is inclined to accept Eisig's invertebrate origin of the lateral organs,

and combats Mitrophanow's statement that they are not metameric.

Ayers (1892, 7) endeavours to show that the auditory organ is not supplied by a discrete

cranial nerve but by the branches of two cranial nerves, /. c. the facial and the

glossopharyngeal ( = tbe vagus: be considers the lateralis lateral line nerve to be a

branch of the IXth). He thus favours tlie metameric view of the lateral organs. On

p. 314 he says : — " As Froriep has shown, the ectodermal thickenings which Beard

described as giving rise to the lateral Hne organs have in fact another fate. The genuine

lateral line organs escaped Beai'd's observation, and in consequence Beard's conclusions

* Sense organs may exir.t withoul dermal tubules (cp. Ewart & Mitchell, p. 10(»), but. mt viva verm.

THE CRANIAL NERVES AND LATERAL .SENSE ORGANS OF FISHES. 151

as to the laomology of the vertebrate avicUtory organ are incorrect "*. Although Avers'

views as to the innervation of the auditory organ cannot any longer be maintained, it is

possible that his latter statement is to some extent sufficiently near the truth to require

a reopening of the whole question of the " branchial " or " epiln-anchial " sense organs.

In his L(cmargi(s j^aper (1892, 68), Evrart supports the view of the innervation of the

lateral sense organs taken by Triant and AUis. He does not consider that Beai-d's

scheme applies to the adult Elasmobranch, nor does he consider the lateral canal as

composed of ontogenetic metanieric sense organs (p. 79). In his paper with Mitchell

we find (69, p. 100) : — " But v/hile the sense organs and tubules have a nietamerlo

arrcmgement in the trunk, there is no relation between the sense organs and segments In

the head region; and, as already pointed out, some portions of the cranial canals, though

possessing numerous sense organs, have no tiilnxles connecting them with the exterior.

In all the cranial canals, l^cjth dorsal and ventral, there are far more sense or"-ans than

segments ; e. g. in the supra-orbital canal there are nearly ninety sense organs, and in the

infra-orbital there are over ninety." Pollard (1.892, 161), referring to the relation between

the lateral canals and the dermal bones, in which connection we should remember Allis's

statements above, says (p. 527) : — " In Clarias it is by no means a rule that pores should

open at sutures " ; but on p. 539 we find the absolutely contradictory statement that

" as the dermal bones are much reduced in Auchcnaspis the close relationship of pores to

sutures, which exists in Clarias, is not seen." Willey (189 i<, 223) makes a somewhat

remarkable statement. He says (pp. 41-i5) : " It seems certain that at first the sense

organs of the lateral line must have been iuncrv^ated by spinal nerves. This follows

both from ti priori considerations and also from the condition in Amphioxus, where the

ectoderm of the metapleural folds is innervated by the Rami ciitanel ventrales of the

dorsal spinal nerves. Under these circumstances it is necessary to supjiose with Eisig

that the lateral line nerve {Ramus lateralis vagi) arose as a collector." I am unacquainted

with any evidence in support of this statement. Eisig's views on the subject I have

already dealt Avith, but I may mention that his explanation of the lateralis nerve has

never been accepted by vertebrate morphologists.

Bashford Dean (1895, 58) evidently considers the metamerism of the lateral canal a

secondary modification. He says (p. 51), after considering the probable phylogeny of

the system : — " The sensory cells are no longer scattered evenly along the floor of the

canal ; they now occur in metameral masses supplied with a distinct nerve branch, located

in the region immediately below the external tubules." Again on p. 52 he remarks : —

" The original significance of the lateral line system as yet remains undetermined.

As far as can be judged from its development, it appears intimately, if not genetically,

related to the sense organs of the head and gill region of the ancestral fish : in resj^onse

to special aquatic needs, it may thence have extended fu.rther and further backward along

the median line of the trunk, and in its later differentiation acquired its metameral

characters." Locy (1895, 130) agrees ndth other observers that the branchial sense

organs of Beard and Froriep are not the lateral sense organs, but may perhaps corre.spond

* When Ayers wrote this he must have forgotten what lie had previously written on n. 213 I

152 ME. r. J. COLE ON THE STBITCTURE AND MOEPHOLOGT OF

to the segmental sensory papillre of Annelids. On p. 577 et scq. he confirms for Squalns

the observations of Wilson on Set^raims and Mitrophanow on Acanthias and otlier

Elasmobranclis as to the common anlage of the lateral sense organs and auditory

oro-an, and states : — " MitroiAanow departs from the nsual point of view that the organs

of the lateral line are metaraeric, and in that particular, I think, I should be inclined

to follow him." Strong (1895, 204) is more emphatic on the point. He says (p. 197) :

" It is also evident that the lateral line system has no specially segmental character,

and that it cannot properly be used in the manner in which it has been attempted to

use it, as a general guide in determining the segmentation of the head."

Miss Julia Piatt (1896, 158) argues from the opposite point of view*. She states

(pp. 502-503) : — " Since Mitrophanow claims as the result of his study that the segmenla-

tion of the lateral-line system is entirely secondary, I shall be interested to discovei; when

I again have my Acanthias material with me whether traces of primitive segmentation so

evident in Necturus cannot also there be found, for it is dilficult to believe that the

great similarity which exists in the position and direction of the main lines of sense

organs in Necturus and Acai/thlas should not be the result of a similar coiirse of

development." Miss Piatt also describes four of the sense organs of the infra-orbital

line as being partly innervated by the ophthalmicus profundus, and concludes (pj). 530-

531) : — " I do not, for this reason, include the trigeminus among the lateral line nerves,

bvit should nevertheless hesitate to say that the ' trigeminus proper does not participate

in the innervation of the lateral line system.' " With regard to the ultimate fate of

Beard's branchial sense organs, Minot (1897, 140) says (pp.706 & 709) : — "We have

further to emphasize those traces which have been discovered of long series of sense

organs, of Avhich the nose, eye, and ear are probably derivatives, in the ancestors

of the vertebrates, although in all known vertebrates most of these series have become

rudimentary or lost. The serial sense organs I designate under the comprehensive name

of ganglionic sense organs. There are probably two, and only two, series along each

side of tlie body : one series, the ujiper, corresponds to the lateral line of comparative

anatomy, the other to the epibranchial line." After pointing out the diiferences between

the two series, he concludes : — " The sense organ above the gill cleft [i. e. branchial or

epibranchial sense organ], though differentiated, is a larval structure only, and disappears

in the adult." Finally Wilson and Mattocks (1897, 226) confirm for Salmo the discovery

already made by the former author in Serranus of a common anlage of the lateral and

auditory sense organs, and state further that the portion in front of the auditory saucer

gives rise by bifurcation to the supra- and infra-orbital canals, whilst the portion posterior

to the saucer grows backwards and forms the lateral canal.

We thus see that the metamerism of the lateral line nerves and their associated sense

organs has for a long time been a problem, the solution of which has been attended with

considei-able difficulties. The older anatomists considered the nerves to be branches

of the trigeminus, facialis, and vagus, until it was shown by Priant in 1879 that the

* But cp. ])p. 4!l2 and 50], which go to show thai Beaid"s branchial sense organs do not belong to the lateral line

system.

THE CEANIAL ]\'ERVES AND LATERAL SENSE ORGANS OF FISHES. 153

nerves usually considered to be branches of the trigemiuus really belonged to the

facial. To Friaut, therefore, belongs the credit of being tlie first autlior to arrive

(approximately) at the truth with regard to the innervation of the lateral sense orgaas.

His work was confirmed by Marshall and Spencer in 1881 and by Mlis in 1889, and it

was thus established that the superficial oplithalmic and buccal lateral Hue nerves

belonged to the facial, rather than to the trigeminal, nerve. The work of Beard and

Froriep in 1885, imjiortant as it is, has added considerably to the confusion wiiich

exists on the subject. There can be no doubt that if the branchial or epibranchial

sense organs ultimately develop into the lateral sense organs of the adult, then the

latter must have been (primitively) segmental structui'es. But we have seen there is

good evidence against the iilentity of the two series of sense organs, and even before

this evidence transpired it is significant that the innervation of the adult lateral sense-

organs could not be harmonised with the supposed embryonic conditions (cp. especially

Allis and Ewart). And added to this the fact that the lateral organs and the auditory

organ have been found to develop from a common sensory anlage, which discovery has

been extended to several forms and has been found to apply to Elasmobraiiclis as well as

to specialised Teleosts, we have an opposing view of the development of the lateral

organs which has the advantage of being easily reconcilable with the facts of adult

structure. This leads us to the latter view of the question.

In his 1889 paper, Allis, independently following Friant, and working on the lines laid

down by Marshall and Spencer, described the lateral line nerves as branches of the facial,

glossopharyngeal, and vagus nerves. In this he was largely followed by Ewart (1892)

and Pinkus (1894)), until it was considered completely established that the lateral nerves

were undoubtedly branches of the facial and vagus, and perhaps also of the glosso-

pliaryngeus. In the meantime Mayser (1882), Pollard (1892), and Strong (1895) had

been working out a totally different hypothesis, the tendency of which was in the first

place to regard all the lateral line nerves as morphologically branches of one trunk, and

in the second to associate that trunk with the auditory irerve and system. This view

was developed by me in my Cliimcera paper, in which I endeavoured to show that the

lateral line system was an independent system of sense organs innervated by a distinctive

and independent series of nerves of characteristic size of fibre, and further that the

whole was the morphological equivalent of the auditory organ, with which it should

therefore be associated. I further stated the belief that the branch of the glosso-

pharyngeus innervating sense organs of the lateral line would be found on investigation

to be a branch of one of the lateral line nerves, and finally, pending further investigation,

provisionally associated the lateral line nerves with the facialis. These views have been

entirely confirmed by recent investigations, such as tliose in 1897 by Kingsbury, Herrick,

and Allis, so that the j)i"esent position, from the point of view of the comparative

anatomist, and setting aside for the moment purely developmental evidence, may bo

summarised as follows : —

(1) The lateral line system is an indejoendent series of sense organs, differing histo-

logically from any other cutaneous sensory system, such as the terminal buds described

by Merkel and other authors, and not innervated by the same nerves.

154 MK. 1', J. COLE ON THE STEUCTURE AND MOEPHOLOGT OF

(2) That this system is innervated by a series of lateral Hne nerves which are un-

doubtedly independent of miy of the recognised cranial nerves, and are in fact mori^ho-

logically branches of one trunk.

(3) That the lateral line brancli of the glossopharyngeal belongs to the lateralis

lateral line nerve.

(4) That the lateral sense-organs and nerves are precisely comparable to the auditory

organ, with which they should be associated — the lateral and auditory nerves arising from

a common centre in the brain which is further peculiar to this system of nerves. It is also

possible that the lateral sense organs, together with the auditory organ, in most forms

arise from a common sensory anlage from the skin.

We have seen that the developmental evidence in favour of the metamerism of the

]ateral line system is too conflicting to be made the basis of any discussion, but there is

no room for doubt that the sense organs of the body canal are often metameric in the

adult, as has been described above. It is hence necessary to enquire into the nature of

this regular occiu-rence of the body sense organs. I have previously pointed out that

the lateral sense organs primitively belong to the head, and have only secondarily

extended on to the trunk. This can be proved both by the development and adult

structure of the lateralis canal. Even in young adults of Gadiis the body canal posterior

to the shoulder girdle is still very imperfectly formed, and in fact is somewhat difficult

to detect in sections. In all known cases of development the body canal grows from

before backwards, and its most posterior part is the last to be formed of any of tlie

sensory canals. When the sensory canals are quite perfect in the head and have fully

reached their adult condition, the posterior section of the body canal is still nothing

more than a mere rudiment or anlage. It is hence impossible to regard any condition

of the body canal as representing a primitive condition, since it is itself only a secondary

structure. The innervation of this canal, however, settles the point. The nerve whicli

supplies it is in all fishes the lateralis lateral line nerve, which, as it is not a collector,

and is absolutely independent of the metameric nerves, must be held to disprove the

essential metamerism of the body canal, and indeed shows that such a condition of

this canal is purely superficial.

Now it is obvious that the independent character of the lateral line system, which is

such a characteristic feature of the post-embryonic conaition of existing fishes and

amphibians, may be either primitive or acquired. It may be, either that the lateral

nerves were originally branches of the various cranial nerves, and that the present

apparent relations with the latter are the vestiges of that connection, or that the lateral

nerves were primitively independent and have already commenced to fuse with, and to

form an essential part of, the true cranial nerves. It seems to me that the latter conclusion,

although it was advocated by myself, is being hastily and injudiciously adopted, and

that further embryological investigations Avill have to be concluded before we liave

sufficient data to arrive at an accurate appreciation' of the subject. The question may

be viewed from the thi'ee standpoints of Embryology, Comparative Anatomy, and

PalEContology. With regard to the former, in spite of the numerous and bulky memoirs

that have been written on the subject by such naturalists as Dohrn, Goette, Balfoui',

THE CRANIAL NEEVES AND LATERAL SENSE ORGANS OF FISHES. 155

Van Wijhe, and Beard, much has yet to be done. From an embvyological standpoint,

the first alternative above is still a possible, if not a probable, explanation of the facts,

and imless the evidence from Embryology is to be rejected altogether, which is out of the

question, it is necessary to wait until further investigation from this standpoint

definitely vipholds one view or the other. Whatever result is finally arrived at, it

should be one in which both embryologists and anatomists concur, and it seems to me

that this result will most probably be one that is adverse to the metamerism of the

lateral organs.

Comparative anatomy helps us but little. It is true that in CUmcBra, which shows

us the innervation of the lateral sense organs in its simplest known condition, all the

lateral nerves, except the external mandibular, arise separately from the brain, and are

not in any way connected with the true cranial nerves. It is also true that as we go

higher in the vertebrate scale we get every possible gradation between this comparatively

independent condition and the very complex one found in the highly specialised recent

Teleosteans — where the mingling between the lateral and cranial nerves is at its

maximum. It is now a question of whether it is permissible to argue from this that

the primitive condition must have been that in which the nerves were concentrated

and independent, and therefore not metameric, since the cartilaginous fishes are simpler

than the Teleostean forms, and fossil Ichthyology teUs us that they have departed less

from the primitive type. Such a contention of course accepts as granted that the

soft parts have advanced pari passu with the specialisation of the skeleton. It is

evidence of perhaps little or doubtful value, but it may, I think, be used to confirm a

view already resting on a more solid basis of fact.

From Palaeontology we learn still less, and it is most valuable when it is able to

throw light on the ancestry of a type that we have other reasons to believe is

primitive. It shows us also that the lateral line system is an extremely archaic

structure, and further that as regards the geograpliy of the sensory canals it has

remained in a largely unmodified condition for untold ages. What bearing this has

on the innervation of the system it would be hazardous to conjecture.

Briefly, the question at issue between embryologists and anatomists is whether

the lateral line system is metameric or not. The most valuable evidence that has

been advanced from the latter point of view is that in which the lateral nerves have

been microscopically traced both to their central origin and peripheral distribution.

Considering this evidence, and pending agreement among embryologists, I take up the

provisional position (which, however, I believe to be a very strong one) that it is not.

I shall therefore in the present communication describe the lateral nerves as purely

independent structures having no connection, other than purely secondary, with the

true cranial nerves.

The following description of the innervation of the lateral canals of Gadus is based

partly on dissections and partly on an examination of serial transverse sections of young

adult Gadus virens (="(?. carbouarms").

SECOND SERIES. — ZOOLOGY, VOL. VII. 22

156 ME. F. J. COLE ON THE STRUCTURE AND MORl'HOLOaY OF

M. Innervation of the Sensory Canals in Gadus. (Plate 22.)

(1) Supni-orhital Canal.

Superficial Ophthalmic Trunk. — This consists of two portions, which are {a) the

supei-ticial ophthalmic of the trigeminus, and {b) the superficial ophthalmic lateral line

nerve. The latter arises from the posterior dorsal edge of the proximal portion of the

lateral line ganglion, and at its origin lies between the ventral edge of the cerebellum and

the anterior extremity of the auditory capsule. Owing to a certain amount of over-

lapping on the part of the facial and auditory nerves, the origin of the lateral oplithalraic

nerve is somewhat difficult to determine, owing to the close apposition of its root to the

anterior edge of the auditory ganglion. It would in fact be difficult to say whether some

auditoi'y fibres did not mingle with the lateral ophthalmic. There are a few ganglion

cells at its base, but otherwise no cells whatever in the course of the nerve, and the few

above belong, strictly speaking, to the lateral ganglion.

The lateral ophthalmic now passes horizontally forwards over the trigemino-facial

ganglion and soon commences to pass upwards. As, however, it leaves the ganglion, it

receives a conspicuous root containing a few ganglion cells from the anterior dorsal edge

of the ganglion, and this is the root of the trigeminal ophthalmic, since it is from the

direct continuation of this portion of the trunk that the general sensory fibres arise. The

root of the trigeminal ophthalmic is at first very flat, and closely opposed to the ventral

surface of the lateral ophthalmic root, but no mingling of the fibres coidd be detected

either at this region or any other.

As the trunk passes gradually upwards towards the posterior poi'tion of the infra-

orbital canal, the trigeminal portion becomes narrower and is almost completely separated

from the lateral portion by a small blood sinus or vessel. Fui'ther forwards, however,

the two nerves become approximated by passing under this vessel. By this time the

nerve has entered what appears to be a rudimentary eye muscle canal, and lies opposite

the ventral edge of the alisphenoid over the posterior portion of the eye, and (iu the

young forms but not in the adult *) somewhat close to the brain opposite the dorsal

border of the optic thalami and the origin of the optic nerves. The twig to the fifth

sense organ of the supra-orbital line is given off from the dorsal or lateral portion of the

trunk at this region. It perforates the wall of the eye muscle canal, passes upwards and

forwards to the outside of the alisphenoid, finally piercing the frontal to reach its

distribution.

Continuing its course, the ophthalmic trunk passes obUquely upwards and assumes a

position between the dorsal border of the eye and the supra-orbital canal. Soon after

supplying the twig to sense organ 5, the lateral ophthalmic gives off a somewhat large

branch [S.O.^) which, after coursing parallel with the main trunk for a short distance,

* The rc4atioiis are by uo meaus the same. Fur example, a trausverse section may pass through both the optic

lobes and a portion of the eye iu the young forms, whereas in the adult no such section could pass through a»y part

of the lirain and eye at the same time.

THE CRANIAL NEKVES AND LATERAL SENSE ORGANS OE FISHES. 157

divides into three twigs whilst still lying near the brain in the eye muscle canal and

opjjosite the edge of the inner ventral process of the frontal. The inner of the three

twigs passes inwards and upwards, perforates the frontal, and lies between the Irontal

and the sensory canal. In this position it passes forwards for some little distance and

innervates sense organ 4 of the supra-orbital line. The remaining two twigs doubtless

innei'vate pit organs in this region.

Opposite the point where the twig to sense organ 4 perforates the frontal, the

ophthalmic trunk divides into two conspicuous nerves, a larger dorsal lateral portion,

and a small ventral trigeminal portion — as is shown by the nerves arising from them,

the lateral-line twigs arising from the dorsal nerve and the general cutaneous fibres from

the ventral iierve. As the trunk passes forwards the division becomes more mai'ked,

until two rounded nerves are distinctly differentiated. The lateral portion soon gives off

a twig which passes uj)wards and enters the frontal slightly anterior to the supra-oi'bital

commissure. It passes obliquely through the substance of the bone inwards and

forwards, perforates it dorsally, lying between it and the sujira-orbital canal, and finally

innervates sense organ 3 of the supra-orbital line. Anterior to the region where this

twig enters the frontal, the two divisions of the ophthalmic trunk begin to approximate

and once more continue their course together. At this region too, a small blind sac is

seen in the sections to open into the supra-orbital canal external and opposite to tlie

supra-orbital commissui-e and partly opposite the fourth sense-organ. It contains no sense

organs and no lateral line twigs could be traced to it, and seems to me to correspond

precisely to a much larger but otlierwise similar structure in the same position described

by Hyrtl in Lota. It therefore possibly represents a degenerate or modified dermal

tubule.

In the region of sense organ 3 the supra-orbital trunk shows a tendency to split up

again, and can clearly be resolved into its two constituents with the higher power of the

microscope. This tendency, however, is soon lost and the nerves become inseparable as

before. It is here, moreover, tliat the ojilithalmic trunk leaves what I take to be the

eye muscle canal, and becomes for the first time perfectly round in transverse section.

It immediately enters the frontal at the junction of the frontal and pre- frontal (= lateral

ethmoid or parethmoid), and courses obliquely inwards and forwards in the spongy sub-

stance of tlie frontal. After leaving the latter bone it enters a large space bounded above

and internally by the frontal and below by the pre-frontal. Anterior to this sjmce the

trunk begins to pass ujiwards and inwards towards the Ligamentous portion of the supra-

orbital canal, which it accompanies, and an examination of it with the high power at

once reveals the distinctiveness of its lateral and trigeminal portions. These again

separate, and the ventral portion or trigeminal ophthalmic gives off a large nerve, which

could not be satisfactorily traced in the sections, bvit seemed to be a cutaneous sensory

nerve *. In front the two ophthalmics again more or less approximate.

Before leaving the space in the frontal mentioned above, the lateral ophthalmic gives

off dorsally a twig {S.O.^) which passes inwards and forwards, curves upwards round the

* The fibres of this nerve undoubted!}' came from the trigeminal ophthalmic.

22*

158 MK. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

anterior edge of the frontal, between the latter and the ligamentous portion of the supra-

orbital canal near the mid-dorsal line, to the inner side of the sensory canal, and was

traced almost on to the skin and then lost. It most probably supplied the pit organs

in that region.

Coincident with the ligamentous portion of the supra-orbital canal, the ophthalmic

trunk separates into its two components, quite obvious with the low power, the lateral

constituent being dorsal and the larger of the two. The latter soon afterwards gives off

a twig which perforates the posterior edge of the nasal, lies between the latter bone and

the supra-orbital canal, and Anally passes obliquely inwards and forwards to supply sense

organ 2. •

The ophthalmic trunk has now completely split up, both components at first lying

close together at the posterior extremity of the nasal, ventral to the latter bone and just

below the supra-orbital canal. Opposite the second sense organ the two components

commence to run alongside again, but do not mingle. Anteriorly the lateral, together

with the greater portion of the trigeminal, ophthalmic pass inwards and upwards along

the inner face of the nasal, and whilst there a trigeminal twig is given off (S.O.^) which,

passing outwards and upwards along the outside face of the nasal, is distributed to the

skin in that region.

Whilst the ophthalmic nerves are passing along the inner face of the nasal the relation

between them is for the first time changed, the smaller trigeminal curling round the larger

lateral ophthalmic and assuming the dorsal position. Opposite the anterior extremity

of sense organ 2 the two components finally separate out and do not for the remainder of

their course come into contact again *. The smaller dorsal trigeminal ophthalmic (S.O.^)

passes rapidly upwards, dividing into two, is distributed to the skin of the dorsal region of

the snout, and, although coursing with the lateral line nerve described in the footnote, is

not in any way connected with it. The large ventral lateral ophthalmic, on the other

hand, jiasses forwards, perforates the nasal opposite the opening of the second dermal

tubide, and terminates in sense organ 1.

(2) Infra-orbital Canal.

Buccal Trunk.

The buccal trunk, leaving the ophthalmic and buccal ganglion, passes downwards and

outAvards through the " trigeminal " portion of the trigcmino-facial complex, and whilst

passing through this ganglion divides into the nerves (1 and 2 below) which issue from

the ganglion at different levels.

(1) Outer buccal branch. — Issues from the trigeminal portion of the V-VIIth ganglion

dorsal and posterior to the second branch. It is smaller than the latter, and gives off',

* Just at. this region a long nerve from the upper ramus of the inner buccal lateral line nerve passed straight up,

crossed the tvro ophthalmic nerves internally, but was not connected with either, curved outwards and round the

dorsal edge of the nasal, and finallv passed downwards to innervate a pit organ opposite the anterior extremity ot

sense organ 1. This curious nerve is not represented in other fishes, and probably consists of lateral superficial

ophthalmic fibres following a buccal course.

THE CRANIAL ISTERVES AND LATERAL SENSE ORGANS OF FLSHES. 159

immediately after leaving the ganglion, tlie otic nei've, being thereafter continued on to

the orbit as the posterior or outer buccal nerve of the buccal trunk. Both these nerves

are described below.

Coursing for a time alongside the outer buccal branch and issuing from the

"trigeminal" ganglion immediately ventral to it, in fact from the maxillo-mandibular

portion of the ganglionic complex, is one of the nerves described by Strong as " accessory

branches of the trigeminus," and also mentioned by Allis (6, p. 605, &c.). The nerve

now described undoubtedly corresponds to AUis's nerve " c " from the maxillo-man-

dibular trunk, and is distributed mostly to the tissues behind and below the eye. Also

issuing from the ganglion at the same level, but posterior to it, and passing at first

outwards and then downwards, is a twig which seems to tally with AUis's branch of the

inferior maxillary " r.lap.do.''' (6, p. 610), since I traced some of its fibres to the dilator-

operculi muscle.

(2) Inyier buccal branch. — Leaves the ganglionic complex ventral and anterior to the

first nerve. As it issues from the ganglion and passes into the orbit it is joined and

accompanied by the maxillo-mandibular trunk, but lies dorsal and somewhat posterior to

it. There is, however, never any connection between them, and sections show the inner

buccal branch to be perfectly distinct, from its origin at the ojihthalmic and buccal

ganglion onwards. The maxillo-mandibular trunk soon begins to separate into maxillary

and mandibular nerves respectively, and as it does so the inner buccal branch passes

upwards so as to lie dorsal to the superior maxillary, when the separation of the maxillo-

mandibular trunk is complete. (I may here remark that the relative positions of the

inner buccal and trigeminal nerves in the orbit are subject to some variation. The con-

dition just described is shown in my second figure. In the sections, however, and in. other

dissections the inner buccal and its two rami were situated below the supeiior maxillai'V

throughout the whole orl^it.) In front the inner buccal crosses over the superior

maxillary so as to lie ventral to it. As it crosses the orbit, and just over the division of

the maxillo-mandibular trunk into its two derivatives, the inner buccal branch divides

into a smaller inner and dorsal portion, and a larger outer and veutral one. These will

be described respectively as the upper and lower rami of the inner buccal branch of the

buccal trunk.

Outer buccal branch. Otic nerve. — This nerve arises from the outer buccal branch

immediately the latter emerges through the pro-otic notch, and then passes straight

upwards but slightly backwards, accompanied by an arterial twig, over the pro-otic and

the external face of the post-frontal, until it reaches a backwardly-directed dorso-ventral

canal bored in the substance of the post-frontal. Having passed through this, it emerges

on the dorsal surface of the skull between the post-frontal and the anterior overlapping

portion of the squamosal. It then passes straight backwards over the squamosal, lying

dorsal to the latter bone and ventral to the infra-orbital canal, until it reaches the last or

11th sense organ of the infra-orbital line which it suj)plies.

Outer buccal branch. Outer buccal nerve. — On leaving the ganglion, this nerve passes

forwards and downwards. It soon gives off a twig which, travelling upwards and for-

wards, pierces the sixth suborbital and supplies sense organ 10 of the infra-orbital canal.

160 MR. ¥. J. COLE ON THE STKUCTURE AND MOKPJIOLOGY OF

Beyond this the outer bviccal takes a sharp turn downwards, but before doing so crosses

internally the vertical portion of the infra-orbital canal almost at right angles, and takes

up a position in front of and above it. Shortly after giving off the twig to the 10th

sense organ, and as the outer buccal enters the posterior portion of the orbit, another twig

is given off, which, passing downwards and forwards, perforates the fifth sub-orbital and

siipplies sense organ 9 of the line. In front of this the outer buccal is seen to sej)arate into

three nerves. One of these is the main portion of Allis's nerve " c " (described above),

which, having hitherto accompanied the outer buccal, now passes upwards to its distri-

bution, whilst of the two ventral twigs the outermost passes outwards and downwards,

jjerforates the fourth sub-orbital, and innervates sense organ 8 of the infra-orbital canal.

The i-emaining one, in front of the twng to sense organ 8, takes a ventral curve, and

after giving off a branch ventrally which was traced to a pit organ situated ventral to the

canal, pierced tlie third sub-orl)ital and supplied sense organ 7 of the line.

Tpnei^ hnccal branch. — This, the larger of the two divisions of the buccal trvmk, passes

downiwards and forwards, as previously described, across tlie orbit, and consists of two

l^arts. The lowei- and larger part soon gives off a twig which, after a long course down-

Avards and forwards (lying internal to the sclerotic), perforates the second sub-orbital and

supj)lies sense organ 6 of the infra-orbital canal. Almost opposite this sense organ

another twig is separated off from the lower ramus of the inner buccal, and in this region

the first and second sub-orbitals are seen in the sections to begin to overlajj. The twig

above pursues a course somewhat parallel to its predecessor, obliquely perforates the

lachrvnial, and supplies sense organ 5 of the line. At about the region of this sense

orean the two rami of the inner buccal begin to separate, tlie ventral one passing down-

Avards and approaching the infra orbital canal, whilst the dorsal ramus passes upwards.

Tlie ventral ramus opposite sense organ 5 gives off another twig, and, joassing rai^idly

downwards, lies near the inner face of the lachrymal, slightly dorsal to the upper border

of the infra-orbital canal. The twig above perforates the lachrymal at the doi'sal border

of the canal, and innervates sense oi-gan 4. After supplying this sense organ the

ventral ramus comes to lie immediately internal to the inner face of the lachrymal, and

exactly opposite the infra-orbital canal. It then gives off a branch which suj)plies

the pit organs ventral to the canal, and immediately afterwards the whole of the nerve

perforates the lachrymal and lies between that bone and the upper and lower borders of

the canal. Tliere are thus three perforations in the lachrymal for twigs of the ventral

ramus of the inner buccal to sense organs of tJie infra-orbital line. Before reaching the

third sense organ the ventral ramus divides into two — the ventral twig sujiplies sense

organ 3, whilst the dorsal passes forwards and supplies sense organ 2 only.

To return to the upjier ramus of the inner buccal. After separating from the ventral

ramus it passes upwards and ventral to the nasal sack, and is joined by a branch of the

superior maxillary division of the trigeminus. The two nerves do not, however, mix.

The ujiper ramus then gives off its first branches, which terminate in the numerous pit

organs in the region of the snout between the supra- and infra-orbital lines. It now

passes downwards and becomes opposed to the inner face of the lachrymal at a spot

immediately dorsal to the place where the ventral ramus passes through its most

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF ELSHES. 161

anterior foramen in the lachrymal. It then courses forwards parallel and dorsal to the

ventral ramus, and, after giving off dorsally more twigs to the pit organs of the snout,

passes slightly downwards, perforates the lachrymal opposite the dorsal horder of the

infra-orbital canal and slightly posterior to sense organ 2, and JiuaUu supplies sense

oi'gan 1.

(3) Kijomandibiihif or Operculo-mandibiilar Canal.

Hyomandibular Trunk.

This large nerve (^), just at its origin from the trigemi no-facial ganglion, is divided liy

the orbital vein into two portions. The anterior ventral portion consists of two parts

representing the morphological palatine and pre- and post-spiracular nerves or the

"facial proper," whilst the posterior dorsal portion constitutes the "lateral line root of

the facial." These constituents run alongside one another external to the vein, but are

soon quite separable by the microscoj^e into an anterior bundle (iZ"'), composed of the

pre-spiracular and main trunk of the external mandibular branch, and a posterior bundle

(if"), which is mostly formed by the post-spiracular nerve, but also includes a branch of

the external mandibular. In dissections it was noticed that the pre-spiracular separated

off before the hyomandibular trunk divided into the two preceding bundles.

External mandibular nerve. — The posterior branch above of this nerve arises as

already described, and then passes straiglit outwards, downwards, and backwards. It is

closely applied to the postero-external border of //\ and receives some lateral line fibres

from it ventral to the orbital vein. As the entire hyomandibular trunk passes down-

wards, on approaching the hyomandibular bone the two bundles E} and E- become

separated so as to form two distinct nerves. The posterior, or smaller of the two (i?^),

which is composed of a branch of the external mandibular -f the hyoide;in nerve, or post-

spiracular division of the facial proper — the latter being the larger bundle, passes

through the oblique backwardly-directed facial canal in the hyomandibular bone, whilst

the larger bundle (_£f') traverses a foramen in the hyomandibular larger, just ventral,

and somewhat anterior and internal to it. Distally the apertures are somewhat widely

separated owing to the backward direction of the facial canal.

The hyoidean nerve + the posterior branch of the external mandibular, on emergino-

from the facial canal, immediately take a sharp turn downwards and slightly backwards,

coursing near and parallel to the posterior edge of the anterior downward process of the

hyomandibular. On leaving the facial canal the two parts of the nerve are seen to be

separated, in the sections the external mandibular being situated externally to the facial

proper component. The two nerves pass downwards and slightly backwards together,

and pass under the preoperculum at the base of the deep notch at its upper

extremity. The external mandibular fibres {W) leave the hyoideus near the ventral

extremity of the facial canal, and, passing outwards, do^vnwards, and backwards, soon

collect into two bundles. The upper passes downwards, perforates the preoperculum,

and supplies the 12th sense-organ of the hyomandibular line. The lower, after a some-

what long course downwards, obliquely tunnels the preoperculum some little distance

162 ME. F. J. COLE ON THE STKUCTUEE AND MORPHOLOGY OF

above sense organ 11 of the line, which it supplies. The motor hyoideus {S*), the post-

spiracular nerve, passes downwards and becomes related to the anterior face of the hyoid

arch. With the distribution of this nerve we are not concerned.

The anterior or larger division of the hyomandibular trunk (M^) consists, as already

described, of two parts : (a) the main trunk of the external mandibular lateral line nerve

{S^) ; and (b) the " internal mandibular" of Allis (i?^). I shall show later on that Allis

was wrong in his interpretation of this nerve, and that it really corresponds to the

modified pre-spiracular nerve, or chorda tympani, of the cartilaginous fishes, and as such

cannot be the internal mandibular, which is a post-spiracular nerve. The internal

mandibular or post-spiracular nerve is really the hyoideus. Sections show that this

trunk consists of two parts, an anterior chorda tympani and a posterior external man-

dibular. The chorda soon separates off, passes downwards, and becomes related to the

posterior face of the lower jaw. On leaving the hyomandibular bone the external man-

dibidar immediately passes straight downwards over the anterior downward process of

the hyomandibular, and accompanied by a blood-vessel which in spirit dissections looks

astonishingly like a nerve *. Shortly after emerging from the hyomandibular foramen a

long nerve is given off from the external mandibular (H"') which passes forwards through

the adductor mandibulse to innervate some pit organs in the neighbourhood of the infra-

orbital canal. It then courses downwards and forwards to supply certain of the pit

organs lying ventral to the hyomandibular canal. Before passing downwards, however,

it sends down a long fine nerve which innervates the jiosterior set of pit organs in

connection with the hyomandibular canal. These nerves are mentioned by Allis (1897,

p. 632). They also midoubtedly correspond to Allis's nerves mef.vl. and Tiief.mdl.

innervating the vertical cheek and mandibular lines of pit organs.

Soon after leaving the canal in the hyomandibular a twig is given off, which, passing

downwards and backwards over the external face of the anterior process of the hyo-

mandibular, perforates the preoperculum ventral and somewhat internal to its anterior

upward process, and just dorsal to the point of the backward process of the quadrate. It

supplies sense organ 10 of the hyomandibular canal. After giving off the above twig

the external mandibular nerve passes downwards over the outer process of the hyo-

mandibular and begins to take a marked turn forwards. Leaving the hyomandibular it

passes over the symplectic, and whilst on this bone gives off the twig to sense orgau 9 of

the line. This twig jiasses forwards over the symplectic, perforates the preoperculum

internal to the facet for the quadrate and at about the anterior third of the facet, and so

reaches its sense organ.

The external mandibular now begins to assume a horizontal position, and arriving at

about the middle of the posterior edge of the symplectic, where the body of the quadrate

overlaps it, passes almost horizontally, but still somewhat downwards, in a rough canal

* Several of the more important nerves in the Cod are aeeompanied by blood-vessels, which often appear, as in the

case of the superficial ophthalmic trunk, to arise directly from the nerve. (They really perforate it.) In

specimens that have been along time in spirit these vessels are remarkably like nerves, ami Jiiive been taken for such

hi/ several natiiralists !

THE CKANIAL NERVES AND LATERAL SENSE OEGANS OF PISHES, 163

formed by the superposition of the quadrate on the symplectic. Whilst passing between

these two bones it gives off the twig to tlie 8th sense organ, which, passing downwards

on the internal face of the quadrate, perforates the preoperculum near the anterior

extremity of its dorsal border (close to the quadrate facet) and thus reaches its

destination.

Having passed between the symplectic and the quadrate, the external mandibular

courses downwards over the inner face of the latter internal to its head, and then by a

downward curve reaches the inner face of the articular, where it lies in a deep horizontal

groove situated at a level somewhat dorsal to this section of the hyomandibular canal

and opposite the head of the articular. Whilst on the head of the articular the twig to

sense organ 7 of the hyomandibular line is given off. This arises somewhat anterior to

the sense organ, passes backwards, enters the articular oi3posite and ventral to the

anterior edge of the facet for the quadrate, and passes transversely through it to its

sense oi-gan. At this point a branch of the inferior maxillary division of the trigeminus

comes down and runs alongside the external mandibular, lying immediately dorsal to it;

but although they may be very closely opposed there is no real connection, the ventral

branches of trigeminal branch curving round the inner and outer surfaces of the lateral

line nerve to reach their destination.

The external mandibular nerve now commences to pass slightly downwards, and first

lies internal and somewhat above Meckel's cartilage, and afterwards, in front of the 6th

sense organ, is situated directly internal to it. The branch to sense organ 6 is separated

off somewhat in front of the twig to the 7th sense organ. It courses forwards and out-

wards, obliquely perforates the dentary, and after running alongside the sensory canal for

some little distance reaches and supplies its sense organ. The mandibularis externus is

now opposed to the inner face of Meckel's cartilage, and there gives off the twig to sense

organ 5. This proceeds downwards and forwards, and, obliquely piercing the dentary,

reaches its respective sense organ. At about this region a nerve is seen to pass down-

wards under Meckel's cartilage from its outer surface and then turn upwards to become

opposed to, but never connected with, the outer face of the external mandibular. It is at

first situated between the latter nerve and the cartilage, but finally comes to lie on the top

of the lateral line nerve at the place where the twig to the fourth sense organ perforates

the dentary. This nerve is undoubtedly Allis's branch " r.ghi.'' * springs from the inferior

maxillary division of the Vtli, and constitutes a part of the innervation of the geniohyoid

muscle. Of the t^\ags to sense organs 3 and 4^ nothing need be said further than that

they passed through separate perforations in the dentary, and that each gave off a very

small bundle of fibres which were traced ventral to the hyomandibular canal and then

lost. They doubtless innervated the pit organs of this region. The external mandibular

is still situated internal to Meckel's cartilage.

Anterior to sense organ 4 the lateral line nerve commences to pass downwards so as to

occupy a position ventral and somewhat internal to Meckel's cartilage. Here also the

anterior termination of the main trunk of the inferior maxillary division of the trigeminus

* Cp. AUis, 6, p. 639.

SECOND SEKIES. — ZOOLOGY, VOL. VII. 23

164 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

is seen lying internal to and above Meckel's cartilage *. In front the external man-

dibular passes still further downwards, finally taking up a position ventral to Meckel's

cartilage and slightly dorsal to the hyomandibular canal. It is still accompanied by

trigeminal fibres, which, however, pass to their destination anterior to the termination

of the external mandibular. Tlie twigs to sense organs 1 and 2 pass tiirough the same

foramen at the anterior extremity of the dentary.

(•i) Lateralis Canal.

The lateralis lateral line nerve j^ursues a course somew^hat analogous to that of the

buccal. It gives off a supra-temporal branch, which corresponds to the otic, and like it

supplies one of the termini of its canal, and then splits into a dorsal and a A'entral ramus

which may be said to coincide with the two divisions of the buccal trunk. The dorsal

ramus innervates the anterior or abdominal lialf of the lateralis canal with its associated

pit organs, and the ventral ramus does the same for the posterior or caudal moiety of the

canal. Both rami are of course typical lateral line nerves, and as such are composed of

special sensory and not of typical somatic sensory fibres. They may be united by one or

more commissures, and together form wdiat are referred to in the text-books as the

" cutaneous branches of the vagus."

Lateralis Trunk.

This large nerve emerges from the medulla at a high level immediately behind the

lateral line ganglion of the trigemiuo-facial complex, in front of the root of the

glossopharyngeus and some distance in front of and dorsal to the root of the A^agus. The

latter nerve arises by a double root from the medulla distinctly ventral and posterior to

the lateralis. On leaving the medulla the lateralis passes downwards and backwards, and

soon swells into the large lateralis ganglion. It still continues the same course and

passes external to the root of the glossopharyngeal, to which, as it passes, it gives a very

small twig which accompanies the pre-branchial division of the IXth. The lateralis

ultimately joins the vagus, Avhich it accompanies, lying external to it. Hitherto there

have been ganglion cells along almost the w hole of the length of the lateralis root, but

as soon as it reaches the vagus the ganglion cells largely disappear, and only a few are to

be seen. Coincident wdth the disajjpearance of cells in the lateralis root is their

appearance in the root of the vagus, in which they multiply as the nerve recedes from the

brain. Both nerves pass throiigh the same canal in the exoccipital, the vagus occupying

the anterior and internal position, and the lateralis stiU possessing a few ganglion cells.

No mixing of the two nerves was observed at any part. Outside the exoccij)ital foramen

the vagus root immediately enters the large compound (?) vagus ganglion, and there is

also a I'urther collection of ganglion cells on the lateralis in connection with, and at the

base of, its supra-temporal branch.

* AUis (6, p. GIO) saj".s that this part of the ini'orior maxillary accompanies the " r. buccalis facialis," but this is

obviously a slip for " r. maudibularis eiternus facialis."

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 165

Supra-temporal branch. — This branch arises from a clump of ganglion cells (which also

extend into its proxixnal portion) from the lateralis immediately the latter emerges from

the skull. It curves round the auditory capsule, and passes at first in a vertical plane

outwards and then upwards. The first bi-anch to be given off is a small posterior one.

It arises from the ventro-external portion of the supra-temporal a little distal to the

ganglion cells, and passes straight backwards, pierces supra-temporal 4, and supplies the

fourth sense organ of the lateral or body canal. It also gives off two branches : first,

a somewhat obvious one, which passed forwards and somewhat downwards, bifurcated,

and was lost on the skin (this was separated off near the origin of the posterior branch

of the supra-temporal) ; second, a bundle of fibres which was given off as the parent

nerve approached the fourth sense organ, and which passed backwards and was also lost

on the skin. Neither of these nerves ended in the vicinity of pit organs.

The larger part of the supra-temporal now takes an upward and forward turn, but

before reaciiing the lateral canal divides into two — a dorsal and an anterior division.

The former {U) passes upwards and crosses the lateral canal internally and posterior to the

entry of the supra-temporal canal, ^vhilst the latter (i*) passes at first straight forwards

just below the lateral canal. JO'' soon divides into two branches. The lower of these

perforates the second supra-temporal and innervates sense organ 2 of the supra-temporal

canal; the upper courses upwards and forwards, perforates the first sujira-temjioral, and

supplies sense organ 1 of the line. L* passes forwards and slightly upwards, passes in

between the opposed horizontal edges of supra-temporals 2 and 3, and thus reaches

sense organ 3 of tlie lateral canal. Just as it passes in between these ossicles it gives

off a twig which jiassed forwards and was lost on the skin above the lateral canal. Here

also there was an absence of any pit organs. It seems to me probable that this branch,

as well as the similar ones first described, arc composed of fibres of the vagus which

have accompanied the supra-temporal nerve and its branches *.

The main trunk of the lateralis, after giving off the supra-temporal branch, passes

downwards, outwards, and backwards, and in the sections is seen to be situated between

the dorsal border of the pseudobranch and the kidney. As it passes backwards it divides

to form two conspicuous nerves, one of wliich is distinctly smaller than the other. The

smaller division passes upwards and outwards over the top of the pseudobranch, and then

straight backwards, but before doing the latter gives off' externally a largish nerve, which

itself separated off a very small twig and then passed straight downwards in the inner

wall of the branchial chamber. I was unable to trace this branch. The parent nerve,

ho\\'cver, then coursed outwards and upwards, pierced tlie first lateral line ossicle, and

innervated sense organ 5 of the lateral or body canal.

After giving rise to the nerve above described the smaller or dorsal ramus of the

lateralis trunk continues to pass upwards and backwards approaching the lateralis canal,

and as it does so it sends off a branch dorsally which passes first upwards and then

forwards for some little distance and markedly dorsal to tlie lateral canal. It was finally

lost on the skin. Almost immediately afterwards another small branch was given oft',

* Cp. particularly description of posterior root of accessory lateral nerve, p, 176.

23*

166 MR. F. J. COLE ON THE STEUCTUEE AND MORPHOLOGY OF

which coursed backwards for an interval with the parent nerve, and then passed upwards,

crossed the lateral canal internally, and innervated a pit organ just dorsal to the canal.

By the time the parent nerve has reached the surface tubule 5 it has come to lie

immediately ventral to the lateral canal. Beyond this tubule the nerve gave off a dorsal

branch which pa«;sed upwards, pierced the second lateral line ossicle, and innervated

sense organ 6 of the line and its two closely associated pit organs. Posterior to the

origin of this twig a smaller one was given off which passed straight up and supplied a

pit organ dorsal to the body canal. Behind this again the branch arises which perforates

the third lateral line ossicle and is connected with sense-organ 7 of the line and its two

neiglil)0uring pit organs.

The ventral or larger ramus of the lateralis trunk coursed backwards and steadily

downwards until reaching the pectoral fin, from which point it passed almost straight

backwards somewhat dorsal to the fin and following the line separating the dorsal from

the ventral musculatiu'e. I was unable, however, to detect any branches from its

anterior moiety.

N. The Structure and Morphology of the Ramus lateralis accessorius.

Synonymy.

(1) Nervus lateralis accessorius (Weber, 1820).

(2) Nerf pterigo-dorsal (Desmoulins & Magendie, 1825).

(3) Ramus lateralis trigemini (Weber, 1827, and most other authors).

(4) Ramus quartus s. lateralis nervi trigemini (Bonsdorff, 1846).

(5) Dorsals Schedelholilenast (Stannius, 1849. Cp. also Hoffmann & Pollard).

(6) Ramus recurrens trigemini et facialis (Stannius, 18i9).

(7) Ramus recurrens facialis (Siluroids. Stannius, 1849. Cp. Pollard).

(8) Ramus cutaneus quinti (T. J. Parker, 1884).

(9) Nervus Weberi (Goronowitsch, 1897).

(10) Nervus accessorius Weberi (iu part. Haller, 1897).

Under the name of " ramus lateralis accessorius " (the reasons for retaining which are

given below) I propose to describe those curious and interesting nerves familiar to all

students who have dissected a Codfish, and which I at first thought were modified lateral

line nerves. A minute investigation of the roots, however, and, further, an examination

of the literature, convinced me not only that this conchision was absolutely erroneous,

but also pointed to the correct view, as I think, of theii- morphological value. This

small investigation also led to an examination of the essential meaning of the so-called

lateralis nerve of the Lamprey, the results of which, however, are given in the

succeeding section.

That the so-called " cutaneus quinti " of Gadus corresponded to the " recurrent facial "

nerve described by Stannius and Pollard, was pointed out independently by Allis and

the writer — the former m his second Amia paper (6, p. 628), whilst a note to that effect

was inserted in the second English edition of Wiedersheim's "Comparative Anatomy"

(221, p. 187) at my suggestion. As, however, we were both anticipated by earlier

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 167

writers, the point is of no importance, but may serve to emphasize the correctness of the

homology.

The first description of the accessory lateral nerve is to be found in E. H. Weber's

famous work on the auditory organ of fishes (1820, 216). He here describes and figures

{i. e. root only, tab. v. fig. 30) the nerve afterwards called the " recurrent facial " of

Silurus glanis. He says : — " Ramus primus nervi trigemini, per tectum cranii exiens,

(in apicibus processuum spinosorum ad caudam usque progrediens, ibique cum nervis

spinalibus ramisque nervi lateralis magni plexum complicitum nervorum componens,)

nervi lateralis accessorii nomine appellandus." There can be no doubt as to the homoloo-v

of this nerve, and it is to be noted that Weber considered it a bi'anch of the trigeminus

and not of the facial as his successors did.

Desmoulins & Magendie (1827, 60) refer to the nerve as the " pterigo-dorsal "

(Part II. p. 869), and were the first to recognise the homology between it and the

superficial nerve of tlie higher Teleosts. They give a fairly long description of its

peripheral distribution in the latter fishes, which is, however, not as accurate as that

published later by Stannius. Weber himself in 1827 (217J devotes further attention to

the matter, and successfully homologises his first nerve with the elaborate cutaneous

system in " Gadus lota " ( =Lota vtdgaris), thus confirming independently the conclusion

of Desmoulins & Magendie. He renames the system the " Ramus lateralis trigemini,"

which is the name by which it has usually been known to anatomists, and describes its

anastomoses with the spinal nerves.

In 1830, Cuvier & Valenciennes devote a section of their work on the Natural

History of Fishes (57) to a consideration of the accessory lateral nerves. They are

both figured and described (t. i. pp. 440-44'l), and erroneously considered to be

largely motor. The anterior and posterior roots are described, and so also are the

anastomoses of the dorsal ramus with the spinal nerves. They found the branches to

the pectoral and anal fins, but not, however, to the pelvic, and clearly recognised the

homology between the recurrent nerve of the Siluroids and the better develojied system

in the specialised Teleosts, believing that representatives of the system were probablv to

be found in all tishes. Their figure of the nerves of the Perch, showing the accessory

lateral nerves, has been copied by Owen (149, vol. i. p. 304), Nuhn (146, p. 558), and into

several other text-books. Biichner (1835, 36) states that the accessory lateral is

characteristically developed in the Cyprinoids, and describes it in " Ci/printis barbus "

{^zBarbus vulgaris), but fails to distmguish it from the lateralis lateral line nerve. He,

however, correctly compares it with its more specialised form in the modern

Teleosts. Alcock (1839, 3) says (p. 268) : " Lastly, in many [fishes] the nerve [trigeminus]

is distributed in a manner and to an extent for which there is no analogy among other

animals, the fins being throughout furnished with branches from the fifth. Hence in

fish, in which the distribution of the nerve is so much more extended than in other

animals, both the size of it is proportionately greater, and it consists of a greater number

of divisions ; these, which in the three other classes of vertebrate animals are only three,

amounting with them to from three to six." A figure of the brain and " fifth " nerve of

the Cod is given on p. 276, which shows the anterior root of the accessory lateral nerve

168 MR. F. J. COLE ON THE STRUCTURE AjSD MORPHOLOGY OF

and its double origin. A brief description of it is also to be foviud in Bonsdorff's

work published in 1846 (30), in which the two roots of the accessory lateral and tlieir

course through the parietal are described in " Gadus lota'' but little is said about its

peripheral distribution, whilst it is again renamed the " Ramus quartus s. lateralis

nervi trigemini."

The description which Stannius gives of the accessory lateral nerves (1849, 199) is

concerned rather with their peripheral distribution, which, as far as the description goes,

is perfectly accurate. Gadus and other Teleosts are carefully described and figured, and

one may mention the figure of the former as being particularly admirable, whilst an

account is also given of the homologous nerves in the Siluroid Teleosts. In establishing

experimentally the somatic sensory nature of the nerves, and confirming the connection

which they have in some of the modern Teleosteans with the dorsal, pectoral, pelvic, and

anal fins, and also with the dorsal bi'anches of the spinal nerves, Stannius went a

long way towards the elucidation of their true morphology, which subsequent observers

failed fco follow up *.

Hoffmann (1860, 100) briefly refers to the accessory lateral of Ci/pn'ims carpio as

the "dorsale Schadelhohlenast " (one of Stannius's terms), but only devotes a few lines

to it. He mentions the connection with the " trigeminus," and figures the posterior root

in Cyprinus. Swan (1864, 205) also mentions it in a few lines, points out the connection

of the dorsal ramus with the dorsal branches of the spinal nerves, and states that the

system is not represented in the Skate. He gives two figures which show the origin

and distribution of the accessory lateral nerves (which he calls " posterior branches

of the filth "), on of the brain and roots, and another illustrating its peripheral

distribution to the dorsal, j)ectoral, pelvic, and anal fins. I believe this figure, which

appeared in the first edition of this work, published in 1835, was the first to accurately

show the peripheral distribution of the accessory lateral system. Baudelot (1870, 15)

briefly mentions and figiu'es it (figs. 2 and 6) as the recurrent branch of the " trigeminus,"

whilst Fee, who describes and figures in a number of Teleosts both the true lateral and

accessory lateral systems, agrees with the erroneous conclusion of Weber that both these

systems are perfectly homologous," although he had noticed that the true lateral nerve

was never connected with the spinal nerves. As the result of numerous experiments Fee

concluded that neither the triie nor the accessory lateral nerves were motor in function.

Owen (1866, 149) says (p. 303): — " A branch of the vagus ascends forward to join the

fifth in forming the dorsal division of the ' nervus lateralis,' which escapes by a foramen

in the parietal bone," by which it will be seen that both the anterior and posterior roots

of the accessory lateral were well known at that date. Baudelot (1868, 11) takes a

somewhat bold step when he compares a recurrent branch of the pathetic nerve

distributed to the pia mater with the ramus lateralis trigemini ! In the same volume

(12), after an investigation of Leuciscus riUilus, he concludes that the true and accessory

lateral nerves are perfectly homologous, and after referring to several authors who had

* As 1 have been working from the second edition of Swan's Atlas, published in 18G4, I am taking it after

Stannius's work. The first edition, however, was published before Stannius's, and anticipated it in many important

respects, especially as regards the branches to the fins and the connections with the spinal nerves.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF i'lSHES. 1G9

discussed the supposed anastomosis of the tnie lateral nerve with the spinal nerves, he

decides in favour of the connection between the two. It seems to the writer, from a

careful examination of the various descriptions of this supposed connection, that the

writers concerned have been dealing with the lateral ramus of the accessory lateral nerve,

and have indeed found the connections they described, but mistake one of the nerves

they were dealing with. However this may be, it is certain that the true lateral nerve

never anastomoses with the spinal nerves.

The "opercular branch" mentioned by Eaudelot (1869, 14) in various Cyprinoids

seems to belong to the accessory lateral system, since it arises partly from the vagus

and partly from the " trigeminus," <ind moreover has a cutaneous sensory distribution.

Friant (1879, 73) describes the origin of the recurrent facial in Cyprinoids and " Barhus

fliwiatiUs''' { = Barbus vulgaris) in terms that practically amount to a brief antici^iation

of Pollard's work. He also describes and figures the accessory lateral nerve in many

bony fishes, including " Gad us cai-honarius'' (pi. v.) and '^ Gadus lota" (j)l. vi.), the

latter showing the system and its anastomoses with the spinal nerves especially at the

pelvic fin branches.

Emery (1880, 66) describes the accessory lateral nerve in Fierasfer as folloA\s (p. 36) :

" n ranio laterale del trigemino e ridotto ad un sottilissimo filamento, il quale corre

sotto la volta del cranio e fuoriesce dietro il margine posteriore del parietale, per

continuarsi, senza ramificazioni, sotto i niuscoli della pinna dorsale ; non ho veduto

anastomosi di questo nervo col vago." The accessory lateral of Fierasfer is thus an

exceedingly simplified edition of the Cod type. Baudelot, in his posthumous monograph

(1883, 16), rediscusses an anastomosis he had previously described (1868, 13) between

the vagus and the "trigeminus." He now compares it with the recun-ent facial of

Cyprinoids, but from his description and figure he must undoubtedly have been dealiu'i-

with a lateral line anastomosis such as that described by Pinkus in Protopterits. This

exj^lanation is further suggested by the fact that his anastomosis communicated with

the auditory nerve. PI. iii., figs. 12 & 13, show a curious origin of the accessory

lateral nerve in Lota vidgaris if correct *. The posterior root, Avith its two vagal rootlets,

is fairly normal, but the anterior root is formed by the union of a small and laro-e

rootlet, both of which arise from the trigemino-facial ganglionic complex. These two

rootlets doubtless sjiriug one from the trigeminus and the other from the facial — much

as in Cypjriiius carpio (Haller). Baudelot figures (pi. v. fig. 3) the roots of the system

in the latter fish, but I propose to rely on Haller's account of them. E-amsay WrifTht

(1884, 228) states that the "Ramus lateralis trigemini" is connected with the first,

second, and third spinal nerves, " and acts as a collector for slenderer branches from all

the other rami dorsales " (Amim-iis), and further that the bulk of its fibres is derived

from the fine-fibred root of the facial. Fritsch (1887, 75) very briefly mentions the

system as the " nervus lateralis trigemini."

In the Sole, the nerve that seems to me to correspond to the accessory lateral of the

symmetrical fishes is, as one would expect, in a very interesting condition. Cunnino-ham

(1890, 55) says: — "The right dorsal branch of the fifth, after its upward course on the

* Not confirmed by Goronowitsch (1S97, 90).

170 MK. F. J. COLE ON THE STEUCTUKE AND MORPHOLOGY OF

internal svirface of the skull, emerges by a small foramen in the flat proximal portion of

the riglit frontal bone, and tlience passes forwards, at some depth from the surfcice,

between the cephalic portion of the lateral muscle and the membrane which forms the

dorsal boundary of the dorsal (left) orbit. It supplies the skin of the extreme anterior

end of the dorsal fin on the upper side. It seems at first sight that this nerve has

changed its morphological relations ; for, since it belongs to the right side of the head,

we might expect to find its anterior part on the ventral or right side of the interorbital

septum, with the right orbito-nasal ; whereas it actually runs on what is morphologically

the ventral side of the left eye, crossing in its course the left olfactory and orbito-nasal

nerves. But the explanation of this apparent anomaly is not diflicvilt. The dorsal

branch of the fifth is a sensory nerve, and was connected in the original symmetrical

fish with the skin of the extremity of the dorsal fin, Avhich was originally posterior to

the eyes. The fin remained behind the eyes during the rotation of the latter, and after

the left eye had travelled round to the right side, the dorsal fin with the neighbouring

muscles began to extend forwards. But instead of extending forwards along the now

distorted median dorsal line, the fin grew forwards along the edge of the left ectethmoid

bone, which supports the left eye in its new position, and which is morphologically

ventral to the left eye. The nerve connected with the fin necessarily accouipanied the

latter in its growth, and thus the nerve comes to be actually dorsal and morphologically

ventral to the left eye. The origin of the nerve remains in its original position, posterior

to the eyes on the right side of the skull." It seems to me that this nerve fulfils

most of the requirements of the definition of an accessory lateral nerve, and it is

interesting to note the light that the peripheral distribution of the cranial nerves

throws on the asymmetry of the skull — in the above case supporting Traquair's view of

the process.

Pollard's description of the " reciirrent facial" in Siluroids (1892, i6i) is somewhat

open to criticism. In Clarias, he says (p. 529) : — " From a posterior dorsally placed

ganglionic extension arises the great Ramus dorsalis recurrens facialis (often wrongly

called trigemini) or ' Schadelhohlenast.' It passes upwards intracranially to the

parietal bone in which it lies, taking its course directly backwards near the depression

in the centre of the parietal. It supplies the mucous canal at the base of the dorsal

fin." Again, on p. 533, in Auchejtasjjis : — " The last nerve to be described is the great

recurrent branch of the facialis. This stoutest of all the nerves passes upwards and

backwai'ds, inclining medianly. In position it arises internally to the anterior semicircidar

canal of the ear, and a portion of its ganglion occupies the common space enclosed by

cartilage. The nerve runs back into the parietal bone, which it leaves before the

posterior end of the cranium is reached. It then takes a deeper course among the body

muscles and divides, one portion passing on probably to supply a dorsal canal, thoiigh

this was not actually ohserved, while the other becomes closely applied to the first spinal

ganglion. No interchange of fibres could be observed, however, and the nerve

penetrates the stout bone which runs out to support the shoulder-girdle in Siluroids,

and follows a direction towards the pectoral fin. In the parietal, as before mentioned,

this recurrent nerce receives the supra-temporal branch from the vagus." (Italics mine.)

In Trichomycterus, he remarks (p. 536) : — " This latter nerve [the recurrent facial] gives

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 171

off remarkably far forward the large nerve which proceeds to the pectoral fin, and which

in this case has unmistakably no connection with the first spinal ganglion." Finally, in

Chcetostonms we find (p. 539): — "The great recurrent branch of the facial leaves the

complex of gauglia belonging to the trigeminus and facial dorsally, and proceeds

upwards to the parietal bone, in tchich it lies for part of its course, receiving the stipra-

temp)orat tjranch of the first vagus branch, and giving off more posteriorly the branch

which passes by the 1st spinal ganglion on its way probably to the pectoral fin."

(Italics mine.)

If the above description by Pollard be compared with the descrij)tion of the accessory

lateral nerve of Gadus given below, it will be seen tliat the two systems of nerves

correspond with each other, detail for detail, in a most remarkable way. As, however, I

can conclusively prove that the accessory lateral is not -a lateral line nerve, it follows,

either that the comj^arison docs not liold good, or that Pollard's conclusions as to the

nature of the recurrent facial are altogether erroneous. The former alternative is put

out of the question by the extraordinary resemblance of the one system to the other. It

is hence necessary to enquire into tlie jiossibility of the latter.

rirst, according to Pollard's o\^-n statement, his work was based entirely upon

sections ; and although this is a very valuable method of investigation, I fully a"Tee with

Allis that unless the results so obtained are as far as possible checked by dissection,

the most disastrous errors are often committed. For example, I should most certainly

have described the accessory lateral of Gadus as belonging to the lateral line system

had I not previously ascertained by careful dissections that it did not. The way in

which the roots of the nerve are applied to the lateral line ganglia {i. e. the external

mandibular and latei-alis ganglia) would deceive the most careful investigator not

working with Weigert sections and not knowing beforehand the macroscopic anatomy of

the nerve. It thus seems to me inevitable that Pollard has mistaken, or rather failed

to determine, the precise origin of the fibres of his recurrent facial *. The only factor

in the peripheral distribution of the recurrent facial which points to its being a lateral

line nerve is the statement that it " supplies the mucous canal at the base of the dorsal

fin." What this canal is must remain a mystery until Pollard's work is revised, since ho

gives absolutely no description of it, nor any figure. In the meantime I agree with the

remark made by Allis (6, p. 627) that " the canal may, however, be of the kind described

Dy Emery as the accessory lateral line of Fierasfer, and hence not comparable at ali

with the canals of the lateral line system as found in Amia and Teleosts." Allis,

unfortunately, is not consistent on the point. He disbelieves in the canal as a lateral line

structure in Polypterus, but accepts as such exactly the same canal in Clarias and

Auchenaspis, without considering the possibility of the innervation of it in the latter

forms having been erroneously described. On the above grounds, therefore, I consider

the " recurrent facial " of Siluroids to be a somatic sensory bat not a lateral line nerve,

comparable in every respect to the so-called cutaneous branches of the trigeminus or the

accessory lateral nerves in Gadus and other Teleosts.

* I am leaving out of consideratiou the origin of the facial portion of the nerve, since Pollard does not mention

from which portion of the complex it arises — whether from the lateral line ganglion or the facial ganglion senun

siricto.

SECOND SERIES. — ZOOLOGY, VOL. VII. 24

172 MR. F. J. COLE ON THE STRUCTURE A^D MORPHOLOGY OF

According to Vogt and Yung (2 15) the accessory lateral nerve must be small in Perca,

in which tliey differ from Cuvier and Valenciennes, but their description and figure do

not agree, and the anterior root of the system must remain a matter of dovibt. Tt is

probable, however, as described by Cuvier and Valencienes (from whose figure that given

in Vogt and Yung seems to have been largely compiled), that this root resembles the

anterior root of Gadus. Willey (1894, 223) considers the accessory lateral to be

comparable to the true lateral system. He says (p. 45) : — " It is not impossible that tlie

lateral line nerve [JR. lateralis ikkj'i) is honiodynamous with the remarkable Ramus

cutaiieus quint i {H. recurrcns trlyeniiid et facialis or Nervus lateralis tri(/emiui, Stannius)

of Teleosteans, which runs to the base of all tlie fins, paired as well as unpaired ; just

as the paired fins themselves arc known to be homodynamous with the median fins. In

this case the H. cutanens qiiinti would be of primitive significance, notwithstanding the

fact that it is absent in Selachians ; and it would be another of those features of

organization in the possession of which Teleosteans exhibit more primitive relations than

do the existing Selachians." I have already emphasized the fact that the accessory

lateral nerves are not in any way comparable to the true lateral system, and hence

Willey's argument, based indeed on an assumption that is "not impossible,"' must fall

to the ground.

Turning to Allis's last work on A)nia (18-97, 6), we find the following passage

(p. 628) : — " Tlie great recurrent branch of the facialis described by Pollard seems to be

the ramus lateralis ti'igemiui of other authors. In Silurns glunis this nerve is distributed

to the dorsal fin, as in Clarias and Aitchenaspis. In Trlcliomijcterus and CluctostoimisSi

large branch is sent from it to the pectoral fin, and in Gadus morrhiia I find this branch

distributed to the breast fin also. In Elasmobranchs and Amphibia the nerve is wanting,

so far as I can find. Its distribution indicates that it is destined largely or entirely to

the sup^ily of terminal buds, for these buds are not found on tlie body in Elasmobranchs

and Amphibia, and are found in great quantity, but with a greatly varied distribution,

on the body, but more especially on the fins, in Teleosts. The nerve in Gadus lies

immediately beneath the skin, but crosses the lateralis vagi internal to the nerve. It

arises as two nerves or bundles from the deeper jjortions of the trigemino- facial ganglion,

the two bundles embracing the i-oot of the buccal and ophthalmic branches of the facialis

exactly as the first pair of branches of the ophthalmicus superficialis trigemini in Amia

embrace the ophthalmicus facialis. The nerve in Gadus has, contrary to the arrangement

of the branches found in Amia, an intracranial course, as it has in Siluroids, issuing on

the top of the skull near its hind end. As the trigemino-facial ganglionic mass lies, in

Clarias at least, inside the skull beside the brain, this difference of course is probably of

no importance."

This passage is unfortunate in many respects. In the first place, the homology

between the Siluroid and the modern Teleostean nerve is, as I have already shown, by

no means new, and has been pointed out by many authors. Secondly, the branches in

Gadus to the breast (=pelvic?) and other fins were described as far back as 1835 by

Swan, and are even described in the practical handbooks {e. <j. Owen's " Vertebrates "

and Parker's " Zootomy "). Thirdly, the accessory lateral is, I think, not Avanting in

THE CEANIAL NEEVES .AND LATERAL SENSE ORGANS OF FISHES. 173

Elasraobranohs, althoiigli I made a statement to that effect in uiy Chinicera paper

(46, p. 663). I find in my notes on tlic Skate [Itaki bdlis) that a large nerve arises from

tlie hyoniandibnlar ti'unk just ontside the auditory capsnle, which, passing ahnost

straight backwards, gradually acquir^'s a sujierflcial position, courses over the visceral

clefts, and ends on the skin of the hack in that region *. It seems to me that this

nerve is the representative of tlie accessory lateral iu the Skate Fourthly, as described

and figured by Stannius, the accessory lateral passes extenud to the lateralis lateral line

nerve. Pinally, and most important, the large posterior or vagal root is completely

overlooked, whicii is the more extraordinary seeing that it also is a text-book fact, and is

described and figured by Owen, Parker, and other writers. It must l)e noted, however,

tnat Allis is perfectly correct in the more essential considerations — first in homologising

the Siluroid " recurrent facial " with the accessory lateral system of tlie modern Teleosts,

and second in regarding the latter as a somatic sensory and not a special sensory or

lateral line nerve.

Allis (1897, 6, p. 599), after describing two ])ranches of the ophthalmicus trigemiui

which seem to me to correspond to the anterior or trigtMuino-facial root of the accessory

lateral system of Gadus, writes as follows (p. 691) : — " Its [the vagus's] small intracranial

branch arises more from the main vagus root than i'rom the dorsal branch itself. It,

however, arises from the fibres that go to form, that hrancli, a ltd hence can be considered

as a branch of it. It runs upward and forward, internal to the root of the lateral nerve,

and issues on the top of the chondrocranium by a small foramen lying near the middle

line of the head, near its hind end. Its further course could not be traced. From its

position, at its exit, it would seem to be the ramus lateralis trigemini, or ramus recurrens

facialis, of Teleosts. Its apparent origin is, however, from tlic vagus, and not from the

trigeminus or facialis. If it be the ramus lateralis trigemini, the first pair of dorsal

branches of the ophthalmicus superficialis trigemini cannot be that nerve, or can only be

a part of it. Botli nerves, and the main supra-temporal as loell, are distributed to regions

where terminal buds are formed, this being espjeciaUy true of the posterior branch of the main

nerve."'' (Italics mine.) Here it will be seen that Allis contradicts his own statement

that the accessory lateral nerve of Amia has not an intracranial course (cp. j)]'evious

quotation). His failure to homologise definitely his two sets of nerves is due, of course,

to his oversight re the roots of the system in Gadus. It is not difficult to recognise his

trigeminal branches as corresponding to the anterior root, and his vagal branch to the

posterior root of the accessory lateral system, as indeed Allis himself surmised iu his

summary (p. 747).

There seems to be no homologue of the accessory lateral nerves in Protoptertis,

according to Pinkus (1891, 157), but the system is briefly mentioned as the "nervus

Weberi" in Lota vulgaris by Goronowitsch (1897, 90), where, as one would expect,

and as far as Goronowitsch's description goes, it closely resembles the same nerves

in Gadus.

* In tliis connection cp. Jackson & Clarke {187(i, loO). It is possible that the nerves they describe as

anastomosing with the tirst spinal nerves may also represent a part of the accessory lateral system.

21*

174 MR. F. J. COLE ON THE STEUCTURE AND MORPHOLOGY OF

The most complete account of the system to lie found in modern literature is that

published in the admirable work on the vagus group of Teleosts by B. Haller in the

third volume of the " Festschrift fiir Gegenbaur " (1897, 97). Haller carefully redescribes

the origin of Weber's accessorius (= accessory lateral in part) in Cj/priiuis carpi 0, where

the accessorius is found in a very interesting, and perhaps primitive, condition. An

anterior root (Taf. ii. figs. 7 & 8 a) is formed by the union of two twigs from the

Gasserian ganglion, one from each side, and two twigs from the facial ganglion. This

root passes l)ackwards and anastomoses with the fused " ventral roots of the vagus "

(Gegenbaur), or what is usvially identified as the Ichthyopsid " hypoglossal.'" Erom the

ganglion of the latter close to the entry of the root above, arises one of the roots of the

accessory lateral system, which passes upwards, receives a root from the vagus, and then

doubtless has the usual peripheral distribution. Before a correct interpretation of these

roots and nerves is possible, an investigation will hiive to be conducted as to the internal

origin and peripheral distribution of the fibres of the roots above described, and this has

yet to be done. My own provisional interpretation differs from that given by Haller,

and is perhaps the more logical one in the present state of our knowledge. We know

that a generalised accessory lateral system would consist of the collected dorsal somatic

sensory branches, or portions of them, of the Vth, Vllth, IXth, and Xth cranial nerves,

and most of the spinal nerves. Haller's nerve a, therefore, form^ what is doubtless the

morphological anterior root of the accessory lateral system. It is anomalous in so far as,

instead of anastomosing directly with the posterior or vagal root, it passes first backwards

to the hypoglossal ganglion. The dorsal branch that leaves the hypoglossal ganglion,

therefore, represents the morphological posterior extremity of the anterior or trigemino-

facial root (Haller's nerve a) of the accessory lateral system, +t^oubtless the additional

dorsal branch of the hypoglossal. The posterior or vagal root is normal. The peculiarity

of the accessory lateral system in Cyprinus, therefore, is that the anterior root first

" collects " the dorsal branch of the hypoglossal, instead of that branch being collected

after the two roots of the system have united and the resulting trunk is passing

backwards. This irregularity has necessarily resulted in the morphological anterior

root as it passes upwards occupying a j)osition posterior to the posterior root. Should

my interpretation of these nerves prove on further investigation to be correct, Cyprlnns

\\\\\ have provided us with a very interesting and unique cliaptcr in the history of the

accessory lateral nerves.

C. J. Herrick *, in a recent note (1S97, 98), describes the accessory lateral nerve of

Meiiidia notata as folloAvs (p. 428) : — " Ramus recurrens VII. Commonly called ramus

recurrens V, but as the fibres are all fasciculus communis, that name is inappropriate.

These fibres arise from the geniculate ganglion in several strands, pass dorsad in the

meninges and finally emerge on the dorsal surface of the head, and then turn caudad

into the trunk. They anastomose with each other, and farther back with the dorsal ramus

of each spinal nerve. I have not been able to demonstrate that they supply either

* This author, bj the way, accuses me in my Ckhmrra paper of associating the lateral lino system with the facial

nerve. He must surely have overlooked paragraph 5 on p. 638, in which I point ont that such an association must

be considered as purely provisional and not morphological.

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 175

canal organs or end buds. Tliey have not, however, been traced caudad more than a few

segments into the trunk. They clearly correspond to the superficial, or accessory

" lateral line," nerves of the Gadoids." Here the lateral line character of the accessory

lateral is out of the question, but I am astonished to find that its fibres all belong to the

fasciculus communis system, since this, as we know from Strong (1895, 204, p. 182),

consists in Amphibia exclusively or almost exclusively of visceral fibres *. It is ti-ue, as

I have previously pointed out, that other recent aiithors have made similar statements,

and Strong himself has been somewhat misrepresented in the matter. The somatic sensory

fibres cannot be considered to belong to the fasciculus communis system, unless we are to

be guilty of the sophism of extending the definition of this system in order to admit

them. The authors in question disassociate viscn-al sensory from visceral motor fibres,

and then unphilosophically proceed to associate somatic with splanchnic fibres and call

the result by a name which was oi'iginally applied to a system of viscei'al sensory nerves.

The system adopted by Strong and Herrick of ascertaining both the internal origin and

the peripheral distribution of the cranial nerve components is the only one by which to

attain results of any value, and we must accordingly await further investigation on these

lines as to the nature of the fasciculus communis system in fishes. In the meantime

we may or may not choose to believe in the conversion of splanchnic into somatic

fibres.

It is hence perfectly clear that the accessory lateral nerves of fishes consist, as has been

proved microscopically, of somatic sensory fibres. And their peripheral distribution has

also been clearly described and figured by many autliors, such as Swan and Stannius.

Their origin, however, excepting the doubtful accessory lateral described by Haller, has

hardly been investigated at all, and the utmost we know is that in many fishes it is

formed by roots from at least two cranial nerves. I therefore made a careful investigation

of the origin of the system in Gadus virens, with the results detailed below.

In Gadus, as is well known, the accessory lateral nerve arises by two roots — a large

stout anterior root, and a much smaller posterior root. An anatomical and microscopical

examination of these two roots reveals the following facts : —

Anterior or Trlgemino-facial root {anatomical). — Arises from the trigemino-facial

ganglion by two rootlets — a larger and a smaller. Owing to the fact that these arise

from the complex just as the latter is passing through and leaving the skull, and as the

nerves are here closely invested by a tough membrane very difficult to dissect off, the

origin of the rootlets is difficult to ascertain. Tlie larger one, however, was connected

by several bundles with the base of the hyomandibular trunk, and the smaller one with

the maxillo-mandibular trunk. The actual origin of the fibres I was unable to

determine by dissection. The two rootlets embrace the trigemino-facial ganglion

in much the same way as the rootlets of the posterior root embrace the trunk of the

vagus.

Anterior root [microscopical). — Both the rootlets arise from the trigemino-facial complex

intracranially, or rather as the complex is passing through the pro-otic notch. The

larger rootlet arises by several bundles from tlie most ventral fibres of the hyomandibular

* Cp. also p]). I9.T-6.

176 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

trunk, /. e. from the facial jii-ojoer. It jjasses upwards and backwards, and is soon

joined by the smaller rootlet wiiich arises from the dorsal or external face of the

" trigeminal " ganglion. In neither case could I trace any connection with lateral line

fibres. By the union of these two rootlets the anterior root is formed, which passes at

first backwards and upw^ards closely wedged in between the pro-otic and the ventral

portion of the lateral line ganglion, from which it might easily be thought to arise,

but with whicli it is not coniiected. Soon after leaving the lateral line ganglion

the anterior root passes almost straight upwards over the cerebellum to reach the

parietal, which it perforates obliquely, and then passes outwards and backwards. Whilst

passing through the parietal canal it receives and fuses with the posterior root from

the vagus.

Fosterior or vagal root {analomical). — Arises from the vagus by two rootlets — a larger

and a smaller, the larger one appearing to arise from the lateralis. Both these rootlets

themselves arise from a number of bundles which embrace and arise intracrcmially from

tlie root of the vagus just as the latter enters the skull. One of these rootlets sent a

very small twig which accompanied the lateralis nerve — this being the only connection

observed between the posterior root and the lateralis, ^'one of the fibres of the former,

tlierefore, are lateral line fibres, but in- some cases the ylossopharymjeus * contributed a

bundle to the root.

Posterior root {microscopical) . — This is variable even in the same specimen. It arises

by two rootlets, as described above, which embrace the root of the vagus not far from its

point of issue from the medulla. These two rootlets join and then pass internal to the

lateralis nerve, being very closely opposed to it, l)ut witli no exchange of fibres. The

root then passes upwards and forwards, and immediately on leaving the lateralis swells

into a large ganglion w^hich was not observed in the sections of the anterior root. The

j)osterior root then passes upwards to the parietal, where it fuses with the anterior root

as previously described. The posterior root may pass external to the lateralis, in which

case it begins to swell into its ganglion before leaving the lateralis, so that the ganglion

as well as the nerve is closely applied to the lateralis. The connection with the lateralis

is very close, and the subsequent central course of the nerve i-equires very careful

tracing.

Connections icith spinal nerves. — The accessory lateral system is connected with the

anterior spinal nerves in Teleosts generally, eitlior directly by means of the spinal

ganglia, or the dorsal branches of the spinal nerves, or indirectly by means of the

branches of the system to the pectoral and pelvic fins {Gadns). As was carefully

demonstrated by Swan and Stannius, the branch of the system to the dorsal

fin communicates in the region of the trunk in Gad its with the dorsal l)ranch

of every spinal nerve (Stannius, 1849, 199, Taf. iv. fig. '±) — a significant fact

which is very helpful in determining the morphology of the accessory lateral

nerves.

* Til many specimens of G. morrJma that 1 distected the glossoi)haiyngeus arose immediately ventral (Did anterior

to tlic loot of the lateralis. This it does in some other Teleo.sts. In the sections of G. virens, however, it arose

liebiiid the lateralis and between it and the vagus, which is its normal origin.

THE CRANIAL NEKVES AND LATERAL SENSE ORGANS OF FISHES. 177

The above consideration of the literature and description of the facts ia Gadiis

enable us to draw u^i the following general conclusions as to the structure and

morphology of the accessory lateral nerves : —

(1) The accessory lateral system of nerves is essentially compound in nature, the

anterior branches as they pass backAviirds acting as collectors and picking up

branches from nerves situated posterior to them.

(2) The systera therefore belongs as distinctively to the spinal as to the cranial

nerves. It originates in the latter, passes backAvards, and collects branches

from the former.

(3) It is distributed to the fins — typically, as in Gadns, to all the fins of the body, but

in some fishes it may l)e di8tril)utpd to only one or more of the fins.

(4) In connection M'ith the fins are a number of tei'minal buds or Eiidknospeii, a)ul

the fibres of the accessory lateral system are largely, if not entirely, in

connection -with these sense organs. The system is therefore both essentially

somatic and sensory in function.

(5) Hence we cannot escape the conclusion that it is formed by the dorsal branches

of the cranial and spinal nerves which the exigencies of their distribution liave

caused to more or less fuse together peripherally.

(6) Fvirther, the ganglion on the posterior or vagal root in Gadns is comparable to the

somatic sensory j^ortion of the dorsal root ganglion of a spinal nerve. This

ganglion (and it is possible thei'e are otiiers) belongs distinctively to the accessory

lateral system.

(7) The system in any one fish may be formed either liy the whole or portions of the

dorsal somatic sensory branches of tlie trigeminal, facial, glossopharyngeal,

and vagal cranial nerves, together with the whole or portions of the dorsal

somatic sensory branches of a varia])le number of spinal nerves.

(8) Upon no grounds caii it be considered as belonging to the lateral line series of

nerves, since it differs irom the latter in three essential respects : (a) in internal

origin; (b) in the character of its fibres ; and (c) in its peripheral distribution.

The one system acts as a collector, whilst the other is absolutely independent of

any of the cranial or spinal nerves.

(9) It is hence imperative to sink such ti'rms as " ramus lateralis trigemini," " ramus

cutaneus quinti," and " ramus recurrens facialis," since no term can Ije

considered satisfactory, or indeed justifiable, which implies that any one cranial

or spinal nerve either invariably takes a part in, or entirely forms, this

complicated system of nerves. I have tidopted the term " Ramus lateralis

aceessorius " for three reasons: (1) it implies nothing as to the formation and

origin of the system ; (2) it was the first term to be apj^lied to these nerves ;

(3) its meaning that it is an accessory lateral nerve is one that may fitly be

applied to it, and is not ambiguous, since the term " lateralis " has been

indifferently applied both to special and general cutaneous nerves *.

* Hence m}- term " lateralis lateral line la-rvo," which leaves no room for doubt as to its distributioji.

178 ME. F. J. COLE ON THE STEUCTUliE AND MOKPHOLOGY OF

O. MoEPnoLOGiCAL Value of the Lateralis Nerve of Petromtzon

Whilst working at the accessory lateral system of Teleosts, my attention became

directed to the " lateralis " nerve of Petromyzon, and it occurred to me, whilst reading

Ahlborn's second paper on the Lamprey, that this nerve was not, as is usually supposed,

a lateral line nerve, but really belonged to the accessory lateral system. The fact that a

definite lateral or body canal is unrepresented in Petromyzon, or at the best only

represented by a few scattered sense organs, shows that the nerve, whatever it may

be, is certainly not a lateral Hue nerve, which confirmed my former impression and

necessitated fvu'ther enquiry into the question.

As far back as 1849, Stannius ( 1 99, pp. 95 and 96) had maintained tliat the lateral nerve

of the Lamprey was not a lateral line but a general cutaneous nerve, but did not compare

it with his " dorsale Schedelhohlenast." Ahlborn (1884, 2) described an anastomosis

between the " lateralis " and the facial, whicli has been compared both with the lateral

line anastomosis of Pi^otopterus and also with Jacobson's anastomosis. Erom wliat has

l)receded it is impossible that it can represent either of tliese nerves. If, on the other

hand, my suggestion be correct, it is easy to see that this anastomosis represents the

anterior or trigemino-facial root of the accessory lateral system.

The short but important paper by E-ansom & Thompson (1886, 165) conclusively

shows (1) that the " lateralis " of Petromyzon is a somatic sensory nerve, and (2) that it

is connected loith the dorsal roots of the spinal nerves. They further state that it hos

no ganglion, and consider it to represent a commissural systetn between the dorsal roots

of the spinal nerves. Dohrn (1888, 62) has endeavoured to show that there is no

connection between the spinal and '• lateralis " nerves, and Beard, believing the latter to

be a true lateral line nerve, also discredits the assumption. He says (1888, 2 1 , p. 215) :

" We know nothing of su^ch connection of spinal nerves with the sense organs of the

lateral line, either now or in the past, and any opinion one may express in favour of

such a view is only an assumption." This is quite true, but does not, as wc have seen,

apply to Petromyzon. Dohrn's denial of Ransom & Thomj)son's statements has not

been confirmed by svibsequent investigation, which has indeed completely established

the connection between the " lateralis " and spinal nerves of Petromyzon.

Eisi"' (1887, 65), who believed the lateral sense organs to be sometimes innervated by

spinal nerves, naturally considered the " lateralis " of Petromyzon a lateral line nerve,

whicli conclusion was also taken for granted by Julin (1887, 109). This author, whose

conclusions were reprinted in his larger work published in the same year (112), confirms

Eansom & Thompson's statements as to the connection of the " lateralis " \\\W\ the spinal

nerves *, but states further that it is connected wdth the ventral roots also. His admission

at the outset of Langerhans' contention that the Lamprey's " lateralis " is a true

lateral line nerve is, omitting that it is a j)ure assumption, unfortunate, since he is

thereby induced to formulate an elaborate theory as to how the connection came about.

* Juliu states in a footnote at the end of his paper that he has discovered connections between the lateralis

lateral line nerve and the dorsal roots of the spinal nerves in cmbrj'os of Scyllrimi and Splnax. This connection, to

my mind most im])robablc, has never been confirmed.

THE CRANIAL NERVES AND LATERAL .SENSE ORdANS OE ELSHES. 179

This tlieoiy, besides being obviously opposed to the facts, is based upon the jjroia5/e

mode of development of the "lateralis" nerve of the Lamprey, and assumes that this

nerve develoj)s in the Lamprey just as it does in Elasmobrauchs.

It seems to me, therefore, that there is room for little doubt as to the morphological

value of the " lateralis " nerve of Tetroinyzon, since all the known facts of its anatomy

point to the conclusion that it Ijelougs to tlie accessory lateral series. First, we know

that its roots correspond to those of the accessory lateral system in the higher Teleosts,

and that besides its posterior or vagal rootlets it has also an anterior or (trigemino-?)

facial root ; second, its fibres are of the same nature, being somatic sensory in function ;

and third, it is connected with the spinal nerves in a manner characteristic of the

accessory lateral series, and such as to justify Kansoni & Thompson's description of it

as a commissural nerve. In these three conditions we recognise the most characteristic

features of the accessory lateral systeur of the Teleostean fishes — features which may

indeed be described as fully diagnostic of this series of nerves. Finally, the " lateralis " of

Fetromyzoii. doubtless does include a few lateral line fibres to the scattered sense organs

of the body, but these are probably contained in a small accompanying nerve and would

of course be morphologically distinct from the main bulk of the " lateralis."

I had written the above before noting that Strong (1895, 204) discusses the same

question, and arrives at conclusions precisely identical with mine. He brings out some

additional points in favour of the view, which practically establisb it as a fact, and

which are included in the folloAving quotation (pp. 199-200; see also p. 157): —

'•Furthermore the N. lateralis [/. e. of Vctromyzoii\ is formed partly by a recurrent

branch from the facialis passing around outside the auditory capsule — a thing which

does not occur in the N. lateralis in the higher forms [except in Protopterus]. Again,

on comparing the course of the N. lateralis with the arrangement of the pits, it is evident

that only a small proportion of them loonlcl he innervated by this nerve, lohich has a

position near the mid-dorsal line. When these facts are considered — especially the

non-derivation of this nerve from the Acuslicus centre, thus differing from the origin so

universal for the N . lateralis in all other forms — it must be regarded as very probable

that this nerve does not represent the N. lateralis vagi of higher forms .... What it

does represent is probably the R. lateralis trigemini, so-called, of Teleosts — ^a nerve

which is formed principally, as we have seen, by a recurrent branch of the facialis,

derived from the lobus trigemini [?], and which is reinforced by a branch from the

vagus. It would then much more probably innervate the papilhe which are so numerous

on the dorsal fin, and which probably correspond to the structures innervated by the

so-called R. lateralis trigemini." (Italics mine.)

P. Gadus compared with other Forms.

Hyrtl (186G, 105) finds the sensory canals of Lota in a very ciu-ious condition. The

lateral or body canals open terminally on to the surface bebind, as also do the supra-

orbital canals in front, and these are the 0}ily communications between the sensory canals

and the exterior («. e. two on each side) ! These openings are situated on fine papilla-.

SECOND SERIES. — ZOOLOGY, VOL. VII. 25

180 MK. F. J. COLE OX THE STRUCTURE AND MORPHOLOGY OF

There are supra-temporal and supra-orbital commissures, and opposite tlie latter on each

side is a large l)lind ciecum, corresponding' exactly to the smaller one found by me in

vounff Grnlus vireiis. As three of these cjieca are also found on the infra-orbital canal

(two posterior and one ventral to eye) in positions occupied in other forms by dermal

tuhules, they doubtless correspond, as I surmised above in describing the one found in

G. vireiis, to modified dermal tulmles. The sensory canals of Lota are, further, largely

ampulliform. In Salmo, "VV. K. Parker (1S73, 152), who regarded the sensory canals as

fflandular organs, describes the hyomandibular canal as communicating with the lateral

or body canal (p. 99), the Salmon in this respect differing from Gadiis.

Prom the description given by Emery (1880, 66) it is (\isy to derive the lateral

canals of Fierasfer ecus from the Gadtis type. There are, however, some differences,

of Avhich the most important are : — (1) there is an anterior infra- and supra-orbital

anastomosis, which is an Elasmobranchian rather than a Teleostean character — the

anastomosis in Amia is between the two infra-orbital canals; (2) the two supra-temporals

anastomose across the back to form a supra-temporal commissure, Avhich is situated

immediately opposite the operculo-mandibular canal and leaves tlie body canal on the

squamosal : the innervation, howeA^er, is precisely as in Gadiis ; (3) there is a supra-orbital

commissure, but the median unpaired tubule is represented by two posteriorly directed

blind sacs ; (4) the operculo-mandibular canal does not end blindly behind, but opens

into the main canal of the head ; (5) the dermal tubrdes are much reduced in number,

and Avhere present are large, blind, and ampulliform as described by Hyrtl in Lota.

Fierasfer dentalus agrees with F. aciis, hut represents a still simpler condition. To put

it briefly, Fierasfer represents a simplified edition of the Cod type.

Sappey (1880, 175) figures (pi. xi. figs. 1 & 2) and describes (p. 43) a very curious

condition of the sensory canals in the " congre commun " [Conger vulgaris). The canals

are reduced to the two lateral or body canals, and a very short operculo-mandibular

canal, Avhich communicates with the body canal on each side and terminates opposite

The angle of the jaw in a large ampulla. In Cottus, according to Bodenstcin (1882, 24),

the geography of the sensory canals is much the same as it is in the Cod. There is a

supra-orbital commissure giving off a median dermal tubule as in Gadns, but the two

•supra-temporal canals also form a commissure. The operculo-mandibular canal does not

anastomose with the body canal. There are fewer dermal tubules, and conseqviently

there must be fewer sense organs. In Amiurus Eamsay Wright (1884, 227) describes

an occipital commissure, but failed to find one between the supra-orbital canals. The

operculo-mandibular canal is separate from the body canal. Fritseh states (1887, 75)

that the lateralis lateral line nerve consists of two (upper and lower) rami as in Gadrn,

which he calls respectively the R. superticialis lateralis vagi and the R. profundus

lateralis vagi.

An examination of Allis's first Amia paper (1889, 4) discloses many points of resemblance

between that fish and Gadtis. We have seen that in the latter fish the sensory canals

have a ligamentous support only in two places. In Amia, Allis says (p. 469) : — " In

their passage from one bone to another, where the bones are not naturally connected,

the canals lie in a dense connective tissue, which forms the deeper part of the cutis.

THE GEANIAL NEEVES A>:i3 LATERAL SEXfSE OKGANS OF FISHES. 181

This occurs particularly between the frontal and nasal on each side, and between

the upper and lower ends of the preojicrculum and the squamosal and angular

[=articular] respectively." In S<diiiu, according to W. K. Parker, the upper extremity

of the operculo-mandibular canal between the preoperculum and the squamosal is

supported by a small ossicle, whilst in Gadits of course the operculo-mandibular canal

ends blindly and is not connected with the main body canal at all. Amia agrees with

Salmo in that the mandibular and body canals are connected near the posterior extremity

of the squamosal. There arc^ two commissures between the sensory canals of Amia — an

infra-orbital commissure at the extremity of the snout, and a supra-temporal commissure

on the back. In Gadus the supra-temporal canals, which correspond jn-ecisely to the

commissure in Amia, are not united across the back, whilst the infra-orbital commissure

is similarly absent, but the supra-orbital commissure, which is very characteristic of the

modern Teleostean fishes, is, on the other hand, wanting in Aii/io.

I have previously remarked (p. 132, also ]). 205) on the anomalous condition of the so-called

squamosal or pterotic of Gadus (PI. 21. fig. 1, Sq.), and it is very interesting to note that

the post-frontal or spheuotic of Aiiiia is in a very similar condition. Allis says (pp. 1.78,

479) : — '• The dermal portion of the post-frontal is a small bone, somewhat triangular in

shape, exactly tilling a large notch extending from the middle of the lateral edge of the

frontal to the hind edge of the bone. Its small posterior end usually fits into a notch on

the anterior end of the squamosal, which overlaps somewhat its lateral edge. It rests

directly upon the deeper post-orbital ossification, and is so closely connected with it that

in attempting to remove it in fresh specimens one of the bones is usually broken, and a

fractured surface ol)tained ; but in skeletons joroperlj^ prepared — by maceration or

boiling — the two bones are easily parted, leaving a clean and perfect surface of

separation." These facts open up questions of considerable import, especially one which

I have previously mentioned, as to how far we may regard the ear ossicles (sphenotic,

pro-otic, epiotic, pterotic, and opisthotic) as modified lateral line ossicles. In any case

it seems to me that the dermal portion of the post-frontal or sphenotic of Amia should

be kepjt perfectly distinct from that bone, and should rank as a lateral line ossicle since

it is developed round a portion of the infra-orbital canal. (But cp. p. 132.) The same

remark applies to the separate pterotic or squamosal of Gad/ts. Both bones are precisely

comparable to true lateral line ossicles such as the lachrymal or preoperculum.

Before proceeding to com25are Amia and Gadus in detail we may note that the lateral

or body canal of the former corresponds to the condition previously described in Gadus.

Allis states (p. 491) : — " Towards the tail there are usually but one or two pores in a

scale, and the development here is of ten so greatly arrested that the lateral canal, through

one or more scales, is an ojjen channel." Again, on p. 504: — "On the body, and

particularly towards the tail, the organs retain nearly this ^^superficial] condition even in

the adult; but on the head tliey are later so much withdrawn from the surface that only

a series of minute holes indicates their position."

In Amia there are 47 * sense oi'gans on each side of the head, counting as far back as

the supra-clavicle, as against 32 in Gadus. These have the following distributioit : —

* Allis (j>. 409) says " forty," but this is doubtless a miscalculation, since the numbers he gives total 47.

25*

182 ME. F. .1. COLE ON THE STRUCTUEE AND MOEPHOLOGY OF

(1) Supra-orhital canal. — In Amia there are three on the nasal and four in the frontal,

of which the first nasal and the last frontal are those perhaps missing in Gadus. In

hoth types the sense organs are fewer than in any of the other canals. The second

dermal tubule of Amia is missing in Gadus, the fourth undoubtedly corresponds to

the 3rd of Gadus, whilst the 6th, 7th, and Sth of Amia are again missing. Indeed,

the Gadus supra-orbital is, for perhaps some functional reason, exceptionally abbreviated,

(2) Infra-orhital canal. — I must first pi'otest against Allis's definition of this canal,

which is very nnphilosophical. He considers i-ightly the innervation of the lateral canals

to be the best criterion of their bovmdaries, and applies this method to all hut the infra-

orbital canal, yet ofi'ering no justification for the exception. Behind the operculo-

mandibular anastomosis the main canal is innervated by the lateralis lateral line nerve

(including the lateral line branch of the IXth, which belongs to the lateralis), and this

should determine the boundary of the body canal : in fact the operculo-mandibular

anastomosis with the main canal is situated between the infra-orbital and lateral canals.

Ewart (1892, 68) also criticises Allis's definition of this canal, and considers, Avith the

writer, that its posterior segments belong to the lateral canal, whilst Miss Piatt (1896,

158) agrees Avith Ewart and correctly limits the infra-orbital canal to the buccal nerve.

I hence consider Allis's sense organs 17-21 infra-orbital to be situated on the lateral or

body canal.

The ethmoid and ant-orbital or j^re-orbital ossicles of ^m«« are unrepresented in Gadus.

Both are probably lateral line ossicles and do not belong to the skull sensu slricto —

the ant-orbital being doubtless a modified sub-orbital plate. This diff'erence makes

it difficult to homologise the sense organs of the two forms, but assuming that the

first post-orbital of Amia represents two fused ossicles, as seems probable, then sense

organs 9 . 10 . 11 . 12 . 13 Amia = 6 . 7 . 8 . 9 . 10 Gadus. Sense organ 14 of Amia in the

sjihenotic is absent in Gadus, but the course of the otic nerve in the latter form is

marvellously suggestive either of its having once existed there, or, what is perhaps more

probable, that it has shifted backwards and now forms the 11th sense organ on the j)terotic.

The otic branch of Amia innervates two sense organs, both on the pterotic, of which the

16th seems to be the one missing in Gadus, since the 16th dermal tubule is absent.

Dermal tubules 13 and 14 Amia are also wanting in Gadus virens, but 13 is present as

No. 9 in G. morrhua. The absence of 13 in G. virens is somewhat remarkable, but I

have not seen it in any of the specimens I have examined. The outer buccal nerve is

represented in Amia by the branches to sense organs 11 . 12 and 13 infra-orbital, with

perhaps the branch to sense organ 14.

(3) Ryomandihular canal. — The dentary of Amia bears 7 sense organs as against 6

in Gadus, but it would be impossible to say which was absent in the latter genus. The

canal then enters in Amia what AUis calls in his first paper the " angular," but is some-

what doubtful about the point. The bone undoubtedly corresponds to the Teleostean

articular, which homology Allis has recognised in his last paper. Bridge's small ossicle

and Allis's ossicle a (1897, 6, figs. 1 & 2) are doubtless comparable to the Teleostean

angular. There are three sense organs in the Amian articular as against one in Gadus,

and six in the preoperculum as against five. In the latter case there can be little doubt

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 183

tbat it is the organ 16 of Allis that is wanting in Gadas, and further that dermal

tuhule 11 Amia corres])ouds to No. 8 Gadus.

(4) Lateralis canal.— lleve it is at once obvious tliat the tirst organ of Amia

situated in the squamosal ( = the glossopharyngeal organ No. 17 infra-orhital Allis) is

absent in Gadus. The next four [Amia) are situated in the single supra-temporal or

extra-scapula, and these doubtless correspond respectively to the first four sense

organs and the four supra-teniporals of Gadus. It is possible that facts like this (and

there are many others) show that each sense organ had originally its own supporting

ossicle. The i^ost-temporal or supra-scapula of Amia has one sense organ, but none in

Gadus, whilst a further difference is that the scapula or supra-clavicle of Amia supports

a portion of the body canal and two sense organs, but takes no part in the support of

the canal system of Gadus. It is true that some authors consider the supra-clavicle a

post-temporal ossicle, but it is impossible to satisfactorily homologise the two bones,

and hence the difference between Amia and Gadus must remain. Behind the region

of the skull and shoulder girdle both forms agree in that the lateralis or body canal is

supported at intervals by small lateral line ossicles.

We thus see that the two forms agree in a very remarkable nianner. This will be seen

if a comparison be made between Allis's tig. 49 and fig. 2 of this paper. Except that

Amia has more sense organs, and omitting differences in detail, the Ganoid form does not

differ as much from the Teleostean form as many of the latter do among themselves.

In fact the resemblances between the two are much more remarkable than their points

of difference. These facts of course strongly support the view originally maintained by

fossil Ichthyologists that the Ganoids cannot be ordinally separated from the Teleosts.

Guitel (1890, 94) describes the lateralis lateral line nerve in Cyclopterids exactly as it

is in the Cod. There are the dorsal and ventral rami — the dorsal innervating the anterior

part of the body canal, and the ventral the posterior moiety. The same author (1891, 95)

has given us a somewhat full paper on the lateral line of Lophlus. He has unfortunately

made an insufficient study of the literature, and hence misnames the nerves. He states,

for example, that the supra-orbital caual is innervated l)y the " ophthalmique du trijumeau,"

and also that a part of the operculo-mandibular line is supplied by " le nerf operculaire

superficiel du pneumogastrique qui echange des fibres avec I'operculaire superficiel du

facial." Further, the infra-orbital canal is said to be supplied by the " maxillaire superieur

du trijumeau." Guitel mentions Allis's first Amia paper, but omits to state on what

grounds he rejects the latter's nomenclature and adheres to the old views. His errors

are perhaps largely explained by the fact that he did not follow out the components of

the nerves with the microscope. A supra-orbital commissure is described as in Gadus.

In Elasmobranchs we find the lateral line system in its most complex form. Beyond

in a very general way any comparison between the sensory canals of Elasmobranchs and

bony fishes is somewhat out of the question. This is very largely due to the absence of

dermal bones, which afford a very valuable guide in determining the homologies of

the individual sense organs and portions of the cinals. Ewart (1892, 68) describes

infra-orbital and supra-temporal anastomoses in Lcemaryus, the former lodging two

sense organs. The infra-orbital ;ilso anastomoses with the supra-orbital and hyo-

184 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

mandibular, and the otic nerve innervates the free anterior extremity of the lateralis

canal, which extremity must therefore be considered to belong to the infra-orbital line.

In the Skate {Mala hatis) the remarkable reduction of the dermal tubules in several

places is a noteworthy feature, and enjoins an investigation into the development of these

portions of the canal system (Ewart & Mitchell, 1802, 69).

Pollard (1892, 161) states that the superficial ojihthalmic and buccal lateral line

nerves arise from a single trunk in Clarias (p. 529) and Auclieiiaspls (p. 532). This

is interesting when we remember the description of the development of these canals

given by Wilson, Mitrophanow, and Locy. In Callicthys, however, the otic nerve arises

separately from the ganglionic complex and not from the buccal nerve (j)p. 534-535).

In Clarias sense organ 1 of the lateralis canal [-— s. 0. 7 main canal, Pollard) is stated

in the text (p. 529) to be suj)plied by the glossopharyngeal, whilst the figure of this form

shows an innervation from the lateralis lateral line nerve. On p. 534 in Callicthys

the ampullation of the " main canal " is described as a " remarkable phenomenon,

hitherto unrecorded in any other animal." It is in fact described by several authors,

notably by Traquair (18G5, 207), Hyrtl (186G, 105), and Sappey (1880, 175). In Clarias,

Auchenaspis, and Choitostomns tb(> operculo-mandibular canal communicates with the

body-canal, but in the Siluroids, where the canal system is reduced, it is unconnected

with any of the other canals. In comparing the lateral line system of Siluroids with

Coccoslens, Pollard apparently overlooked until too late the accurate description by

Traquair published two years before, and makes use of the somewhat erroneous figure

by Pander.

The lateralis lateral line nerve of Ferca, according to Cuvier and Valenciennes (1830,

57;, Vogt and Yung (1894, 215), and other authors, is in much the same condition as in

Gadus, dividing into an upper ramus to the anterior portion of the body canal, and a

lower ramus to the posterior portion of the same canal*. Herrick (1897, 98) finds in

the highly specialised Acanthopteran Meuidia that although macroscopically the nerves

are fused and their relations disguised, yet microscopically the whole of them may be

reduced to the common tyj)e, of which Lmmargus, Raia, Chimcera, Protopterus, Amia,

Gadus, and the Siluroids are other examples. The vagus ganglion can be broken up

into five ganglia — four of which belong to the branchial nerves and one to the visceralis.

Herrick finds the body canal of Menidia occupying a superficial position posteriorly just

as it does in Gadus, and further points out that the lateral line branch of the glosso-

pharyngeus is really a branch of the laterahs. The common origin of the lateral line

and avxditory nerves is confirmed, and the V-VIIth nerves arise by a double root as in

Gadus, of which the ventral one is the motor root of the facial and is connected with

the hyomandibular trunk only. All the lateral Line nerves, except the lateralis, arise

from the dorsal root of the trigemino-facial complex, but in two handles — a dorsal

bvmdle for the superficial ophthaluuc + l^^i^ccal, and a ventral l)undle for the external

maudibidar. The otic nerve innervates three sense organs, whilst two aj^parently derive

* In ri-otoji>tt:rvii thfic are four rami to the lateralis, and nil (lislliiciivih/ laUrcil line nerves (I'inkus, 1894, 157),

whilst the aceessorv lateral system is eompletely absent.

THE CRANIAL NERVES AND LATERAL SEXSE ORGANS OF FISHES. 185

their innervation from the glossopharyngeus. There is thus a general agreement hetween

Gaclus n,ndi Ilenidia, nx\A the differences hetween them are certainly not greater tlian

hetween Gcuhis and Amia.

Q. The Lateral Sexse Ohgans of Vertebkatks and Invertebrates.

Before proceeding to discuss tlie phylogeny of the lateral sense organs, it is first

necessary to enquire into the evidence relating to their supposed homology with the

lateral organs of Invertehrates, as maintained by Eisig, Whitman, and other authors.

The bulk of the evidence is against such an homology, hut the position of some morplio-

logists with regard to tlie question renders its discussion somewhat necessary.

Leydig (1868, 126), who was one of the first authors to conclude tliat Savi's vesicles,

Lorenzini's ampullae, and the sensory canals all Ijelonged to the same system, /'. e. the

lateral line system, was also the first to connect the Ititeral sense organs with the sense

organs of Annelids. This view was, however, first elaborated in detail by Eisig (1879,

64, and 1887, 65), who in his Naples monograph devotes considerable attention to the

question (pp. 501-517). He endeavours to show that the two series of organs are

homologous in all essential respects, and even goes to the length of compai'ing a trans-

verse section through the branchial region of a Vertebrate with an inverted transverse

section of a Capitellid worm. Tlie resemblances to which be draws attention in this

connection are of a very superficial character, and certainly not sufficient to establish the

relation of the two sets of sense organs on a reliable foundation. Eisig seems to have

been misled by mistaking the lateralis nerve of the Lamprey for a true lateral line

nerve, for his theory demands that the lateral organs of Vertebrates should be metameric,

and the lateralis -hqvyq oi Petromyzoii, it 11 lateral line nerve, would strongly support

that view. We have ah-eady seen, however, that the bulk of the evidence is against the

primitive metamerism of the vertebrate lateral line system, and this consideration in

itself is sufiicient to disprove the theory that Eisig seeks to maintain. Balfour, writing

however, before the publication of Eisig's mature views, says (1881, 9, vol. ii. p. IIS) : —

" The organs which resemble those of the lateral line are the remarkable sense organs

found by Eisig in the Capitellida3 ; but I am not inclined to think that there is a true

homology between these organs and the lateral line of Vertebrata."

In his first paper. Whitman (1881, 219) compares the segmental sease organs of

the Leech with the vertebrate latei-al line, and believes that both may be traced

back to a common origin. In his next work (1889, 220) he considerably develops this

view, and considers further that the lateral organs have served as a starting point not

only for the taste organs, nose, and ear, but also for the eye. He assumes, what is

indeed possible, that the vertebrate lateral organs were derived from invertebrate sense

organs of some sort, but it is only adding assumption to assumption to further postulate

a metameric arrtingement for tliese sense or<raus. The evidence is in fact whollv

insufficient to justify a comparison between the two series of organs, and it is hence

to be regretted that Dr. Whitman did not, as far as I am aware, fulfil his expressed

intention of publishing more fully on the question.

186 MR. r. J. COLE ox THE STEUCTURE AND MORPHOLOGY OE

Beavd (1888, 21), who at first combated Eisig's views, finally accepts them in the

following words (p. 21G) : — " Like Dr. Eisig I support, as the result of these researches,

Kleiuenherg's view of the homology of the spinal ganglia of Vertebrates, and the

parapodial ganglia of Annelids. But I go further, and say that what in the sense given

above may be called the cranial neural ganglia of Vertebrates, are also moi'phologically

equivalent to the parapodial ganglia of Annelids. I am also fully prepared now to

accept with Eisig the homology of the branchial sense organs of Vertebrates with

the Seitenoro-ane of Annelida." That the branchial sense organs, which are doubtless

more archaic structures than the lateral sense organs, and were perhaps, if not now,

primitively segmental, corresj)ond to the segmental sense organs of Annelids is most

probable, but w^e have already seen that the branchial sense organs are not the lateral

line organs, and hence Eisig's comparison must in the meantime lapse.

Further opposition to the Annelidan homology is supplied by Wilson (1891, 225), who

opposes Eisig's views, and points out, what we now know to be true, that the Capitellidan

lateral sense organs have a totally different development to the lateral organs of Verte-

brates. Ayers (1892, 7), after insisting that the " auditory organs of Invertebrates are

not the forerunners or the ancestral forms of the vertebrate auditory organs " (p. 317),

remarks that " it is of course possible that other sense organs of the invertebrate body

have developed in the course of descent into the canal organs from which the vertebrate

ear arose." Mitrophanow (1893, 143) is very emphatic on the point. He maintains

that the lateral sense organs of Vertebrates have nothing in common with the lateral

organs described by Eisig in Capitellids, and states, what I have previously discussed,

that the former are not metaraeric (pp. 211-216) — a vital difference between the two

series of organs. Finally, Leydig (1S95, 128) and Locy (1895, 130) are somewhat in

favour of the comparison, the latter, however, Avhilst connecting vertebrate with inverte-

brate sense organs, considering the branchial sense organs, and not the lateral organs,

to be the homologues of the sensory papillae of Annelids.

To sum up, there are two, to my mind fatal, objections to Leydig's and Eisig's views

that the segmental sense organs of Annelids are the direct homologues of the lateral

sense organs of Vertebrates. Before such a comparison can be said to hold good,

the most essential feature of the invertebrate organs, i. e. their metamerism, must be

satisfactorily established in their supposed homologues, the vertebrate lateral sense

organs. We have already seen that the latter are metameric only on the body, and

that this metamerism is purely secondary, whilst there is practically no evidence to show

that the vertebrate organs were primitively segmental. My second objection is based

on the palseontological fact that the vertebrate lateral line system is an extremely

archaic structure. It existed in the oldest fossil fishes known, i. e. in Silurian times.

If, therefore, we accept Dr. Eisig's homology, we must believe that the sense organs' of

the specialised Annelids have had an ancestral history equaUy archaic. This of course

is possible, but it is to my mind too improbable to base even a speculation upon, and

perhaps what shadoAV of possibility it has is removed by the fact that the Invertebrates

possessing lateral sense organs cannot be considered primitive forms.

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 187

R. The Phtlogeny of the Lateral or Sensory Canals.

The solution of this jjroblem directly follows ou the systematic arrangement of the

known facts of the anatomy and development of the lateral line system. The history of

our knowledge of the phylogeny of the sensory canals is coincident with three

discoveries — the discovery that the " mucous "' canals contained sense organs, the

discovery of Savi's vesicles, and the discovery of the ampulla of Lorenzini. As I

propose to view the evidence in a somewhat new light, and hope to indicate the various

stages through which the sensory canals have passed before reaching their present

condition, I have devoted a section to the consideration of the above question.

Lorenzini's discovery of the existence of the ampulliform type of " mucous " organ,

as apart from the canal type discovered by Steno, was further augmented in 1814 by

Savi (178), who described (pp. 332-340) on the ventral surface of Torpedo a number of

sensory pits which he called the " appareil folliculaire ncrveux," and which he thought

w^ere innervated exclusively by the Vth nerve, and failed to find in other forms.

He was further unable to determine either their homology or their function. We now

know that all three types belong to the lateral line system, and I shall suggest that

they represent three stages in the development of a canal — the most superficial con-

dition, represented by the i)it organs and Savi's vesicles ; the full develoiDment, represented

by the canal ; and the intermediate type, forming neither a Savi's vesicle nor yet a canal,

represented by tlie ampullar of Lorenzini.

In 1852, H. Miiller (145) stated his belief that the " mucous" canals were primarily

a sensory and only secondarily a mucous apparatus. He and Ley dig were the first

authors to rank together as sensory structures the pit organs, ampullae, and " mucous "

canals of Savi, Lorenzini, and Steno. McDonnell, how^ever (1860-71, 137), still con-

sidered them to be organs for the secretion of mucus, nor did he think that Savi's

vesicles belonged to the lateral system. The latter view is shared by Boll (1875, 27),

who believed in the independent nature of Savi's vesicles, nor did he consider them

connected with the electric organs as some authors had done. He states, as Savi did,

that they are innervated by the trigeminal nerve. Dercum (1880, 59) goes further,

and considers both the vesicles of Savi and the ampullae of Lorenzini to be independent

of the " mucous " canals.

An important contribution to the question is supplied by Emery (1880, 66), who,

as far as I am aware, first discovered what undoubtedly correspond to Savi's vesicles

outside Torpedo (/. e. in Fierusfer). These organs are situated at the bottom of

epidermal pits — each pit communicating with the surface by a slit like aperture, and

containing only one sense organ, which corresponded in structure with the sense organs

in the lateral canals. They were found in regular lines on the body, and in some of

the lines tlie sense organs -were connected bij shalloto longltadlnal epidermal depressions.

These organs, besides corresponding to the vesicles of Savi, are further homologous with

the pit organs of Allis and tlie " Spait-papillen " of Eritsch and Ewart & Mitchell.

Eritsch's term was obviously suggested by the nature of the apertures of the sacs.

Whilst I do not mean to assert that the vesicles of Savi, the sensory depressions of

SECOND SERIES. — ZOOLOGY, VOL. VII. 26

188 ME. F. J. COLE OX TJIE STRUCTUEE AND MOEPHOLOGY OF

Emery, the pit organs of Allis, and the " Spalt-papillen " of Fritsch and Ewart &

Mitchell are the same in every structural detail, it cannot be denied (1) that all these

organs belong to the lateral line system, and (2) that they are all varieties of one form

of sense organ representing the first stage in the phylogeny of a sensory canal.

Merkel's work (1880, 138), published independently of Emery's, places the whole

question on a solid basis of fact. He showed that there were several kinds of epidermal

pits, all differing but slightly from each other, and yet roughly characteristic of the

different groujisof fishes. His sharp distinction between the " Endknospen " or terminal

buds, which do not belong to the lateral line system at all, and the sensory pits, which

do, has been of the utmost service in determining the homology of the latter in the

various groups of fishes. He further pointed out that the presence of these pit organs

is correlated with the occurrence of other sense organs of the lateral line system,

i. e. that they were most numerous in tliose Teleostean fishes Avhere the canal organs

were reduced in number, and practically absent in the Elasmobranch fishes, cohere they

are replaced by the ampvlhe of Lorenzini. The importance of tliis fact will be

emphasized further on. Sappey (1880, 175) makes some curious mistakes. He con-

siders Lorenzini's ampullae to be " glandes," bvit distinguishes between the ampullary

system and the canal system — the latter having no " glandes" and consisting of canals

opening on to the surface by a variable number of tubules ( = dermal tubules). Sappey

believed the "non-glandular" sensory canals to be probably tactile in function.

It is interesting to note that Solger considered a line of pit organs to represent a

potential canal, and he describes (1880, 193) the lines of pit organs accompanying the

lateral or body canal as accessory lateral lines.

Balfour's views on the question are in many respects prophetic, and of such importance

as to be quoted hi extenso. He says (1881, 9, vol. ii. p. 445) : " It is clear that the

canal of the lateral line is secondary, as compared with the open groove of Chimaira or

the segmentally arranged sense bulbs of young Teleostei ; and it is also clear that the

l)hylogenetic mode of formation of the canal consisted in the closure of a primitively

open groove. The abbreviation of this process in Elasmobranchii was probably acquired

after the appearance of the food-yolk in the q^q,, and the consequent disappearance of

a free larval stage. While the above points are fairly obvious, it does not seem easy to

(lecde a priori whether a continuous sense groove or isolated sense bulbs were the

])rimitive structures from which the canals of the lateral line took their origin. It is

equally easy to picture the evolution of the canal of the lateral line either from (1) a

continuous unsegmented sense line, certain points of which became segmentally dilferen-

tiated into special sense bulbs, while the whole subsequently formed a groove and then

a canal ; or from (2) a series of isolated sense bulbs, for each of which a protective

groove was developed, and from the linear fusion of wliich a continuous canal became

formed*. Erom the presence, however, of a linear streak of modified epidermis in

larval Teleostei, as well as in Elasmobranchii, it appears to me more probable that a

* Siiiee this was written, Allis has described the lateral canals of Anim as arising in jireeisely the manner here

described (i. e. 2).

THE CKAXIAL NEKVES AND LATEiiAL SEN«E OEGANS OE EiSHES. iHt)

linear sense streak was the primitive structure from \ylucli all the modifications of the

lateral line took their origin, and that tlie segmentally arranged sense bulbs of Teleostei

are secondary dilfcreutiatious of this primitive structure." Wright (1884, 227), who

insisted on the liistological difference between the terminal buds of Merkel and the

lateral sense organs of Amiurus, re-discovers the pit organs of Emery and Merkel *, and

calls them the " accessory lateral organs," whilst Eisig considers the mucous sacs of

Myxine to be very ancient structures and homologises them witli the lateral mucous

organs of Annelids. He further thinks it probable tliat tlie latter have been incorporated

or bound up with the vertebrate lateral line organs.

The cousins Sarasin, who believed that all the cells of a lateral line organ were formed

by the division of a single cell, announce the interesting discovery of two accessory

sense organs in Ichthyoplus (1887, 177J. One of these organs is a flask shaped structure

containmg a club like " cupola," and which is called the " Nebenohr " or " Becherorgan."

An examination of the description of this structure at once suggests the probability that

it corresponds to a Lorenzini's ampulla of a cartilaginous fish. Tlie other sense organ

is a more superficial structure, and this may be said to represent the fish pit organ as

described by Emery, Allis, and Ramsay Wright. The peculiarity about the various

species of more or less superficial sense organs found in Fishes and Amphibia is that

whilst they are sufficiently similar in structure to denote a genetic affinity, yet the

corresponding organs in different types never precisely agree.

Eritscli and Garmau were, as far as I am aware, the tirst authors to state that the

pit organ class of sense organ belonged definitely to the lateral line systeui. Earlier

authors, as already stated, had agreed in ranking together the three classes of integu-

mental organs as sensory and not mucus secreting structures, but hitherto no one had

recognised that ISavi's vesicles, pit organs, &c., Lorenzini's ampuUaj, and the lateral

canals themselves, all belonged to one and the same system. Eritsch's works

(1888, 76, & 18'JU, 77j contain the tirst description of the " Spalt-papillen " of Raia

previously referred to, and wliich I homoiogised with the pit organs and Savian vesicles

of other forms, whilst Garman not only recognised the connection of the pit organs

with the lateral line system, but also rightly saw in them organs in an intermediate or

transitory condition. He considers in tact that the pit organs are on their way to

becoming canal organs, but his assumption that they are consequently f uuctionless is a

physiological anachronism which is somewhat out of the question.

In his tirst Amia paper, Allis (188!), 4) describes the development of the sensory canals

as occurring in the manner foreshadowed by Balfour. He says (p. 536) : " The canal

organs also sink below the surface, but they carry with them the surrounding tissues, and

by a process of infolding become enclosed in short canals, each containing a single organ.

These shurt canals then become continuous, a single surface opening being left between

every two consecutive oi'gans along each line. These simple openings, or primary ]>ores,

may be retained in the adult, but most of them undergo a repeated dichotoinous division,

thus giving rise to groups of surface jiores and to corres^'oudiug dendritic systems of

* Wright, however, was wiitiug without access to Merkel's work.

190 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

canals." Before this can take place, however, the anlage of the system must be formed,

and Allis finds (ji. 535) tliat " each group [/. e. line of sense organs] develops from the cord

of cells lying iix the deeper layers of the eiiidermis, and each cord from a special sensory

thickening, which when first seen from the surface in S2:)ecimens liardened in chromic or

picro-sulphuric acid, appears as a large, whitish, and slightly raised spot." From this

anlage all the canal organs arise, and " in the early stages of their development lie

below the surface, but they soon push through the overlying epidermal cells, and their

upper central portions become exposed. Each pit organ subsequently sinks slightly

below the surface, and a little epidermal pit is formed above its central portion " (p. 536).

The canal organs are develojied as above described. Combining Allis's results first

with the work of Balfour and the eai'lier embryologists and then with the recent

observations of H. V. Wilson, Mitrophanow, and Locy, we are enabled to draw up the

following scheme * of the development of tlie lateral canal system, which is known to

apply to some, if not to all, fishes : — (1) A small sensory anlage arises in the neighbourhood

of tlie ultimate position of the auditory organ, the differentiation of which gives rise both

to the auditory organ and the system of sensory canals. (2) This anlage grows forwards

and backwards as a non-segmental cord of cells. In front this cord bifurcates and forms

the anlagen of the supra- and infra-orbital canals. Behind it forms the anlage of the

lateral or body canal. (3) Along the non-segmental cord arise series of sense organs,

which, in the case of the body canal are segmental, but are not known to be such in

the other canals. (4) Each sense organ sinks down, carrying \he skin with it, so that it

ixltimately lies at the bottom of a groove. The lips of the groove fuse — each sense

organ therefore lying in a short tube opening at each end on to the surface by a pore

( = "half pore," Allis). (5) The short tube extends both ways and fuses with the two

adjacent tubes, adjacent half pores fusing to form a single " primary " pore which in most

fishes forms the external aperture of a dermal tubule. In the Ganoid fishes the primary

pore, by a process of repeated dichotomy, produces what is known as a " dendritic system."

A lateral canal is therefore formed by the end-to-end fusion of pieces or segments, and

not by the formation of a primitive continuous furrow, and it further follows that there

must have been primitively a dermal tubule between every two adjacent sense organs.

Bateson (1889-90, lo) fails to distinguish between terminal buds and pit organs, and

although pointing out that these two sets of organs have not the same histological

structure, seems to have overlooked the previously described fact that the pit organs

belong to the lateral line system. According to Coggi (1891, 42), Savi's vesicles

develop in the same Avay in Torpedo as the sense organs of the lateral canals, but his

description differs somewhat from Balfour's observations on Scyllinm. Ayers (1892, 7),

who occupies an isolated position on some aspects of the question, believes Savi's

vesicles to have been produced retrogressively from canal organs, and considers that

they are " without doubt descendants of the canal organs " (p. 164). He bases this

opinion on the observations of Fritsch, which he thinks show that the Savian vesicles

* This scheme ignores the opereulo-mandibular caual, of the development of which our knowledge is still very

imperfect. I sec uo roa-^on, however, wh}' it should not develop in just the same way as, for example, the infra-

orbital does, i. e. by branching from the main trunk.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 191

" are transformed from the canal type during ontogeny," and concludes that " the

Torpedoes possess a system of organs which is lacking in all other Batoids, but which

is represented in these forms by the more primitive canal type." It cannot, I think,

be admitted that there is any foundation for the view that Savi's vesicles are deirenerate

canal organs. The observations of Allis, Coggi, Boll, Merkel, and numerous other

authors, show that the pit organs, Savian vesicles, and other more or less superficial sense

organs, develop as the canal organs do up to a certain stage, but that there they stop.

There is no evidence of retrogression, and none in fact that any of the lateral line organs

ever acquire a more central position than that which they ultimately occupy in the adult.

The fact that a sensory canal of one form may be represented by a line of pit organs

in another, may be more reasonably explained by precisely the opposite hypothesis,

i. e. that the one type represents a more advanced condition than the other. This is

the view adopted by most morphologists, and the one that has the sanction of

the facts *.

The pit organs oi Amia are correctly homologised by E wart & Mitchell (1892, 69)

Avith the sensory follicles they described in the Skate; and the '' Spalt-papillen " of

Fritsch. Bashford Dean (1895, 58), in referring to the pbylogeny of the lateral canals, says

(p. 49) : — " The ancestral condition of the lateral line of Sharks appears to have been

represented in an open continuous groove, lined with ciliated sense cells, and protected

only by an overlapping margin of sliagreen denticles. In this condition it at least exists

in the ancient Sharks and in CJiimcera. That the canals of the head rea-ion were also

primitively of this character appears cvceedingly probable; they are thus retained in

the adult Chumera." Ley dig (1895, 128) gives a brief expression to a very important

and significant fact when he states that there are so many varieties of lateral sense

organs, from the superficial organs to the canal organs, that it is impossible either to

divide them into groups or even to draw sharp lines between individual forms.

A passage in Miss Platfs work on Nectariis {I'fi^Q, 158) is interesting in this con-

nection. She says (p. 526) : — " At each side of a mid-dorsal fold in the skin a row of

mucous glands is found, composed of a few cells invaginated from the deeper layer of the

ectoderm, and now lying below the surface, tiny balls of cells surrounding a central

cavity that opens to the surface by a small pore. Similar glands are found on the

ventral surface of the body between the fore-limbs, and on the tail. Although these

glands are about the size of sense organs, nothing in their structure or in the manner of

their development suggests the genetic affinity of sense organ and mucous gland on

which Leydig [1895, 128] insists." Whilst it is true, as Miss Piatt maintains, that

there is no genetic affinity l)et\veen the lateral sense organs and mucous glands, it is also

true that a lateral sense organ consists of sensory and secretory portions, and it is indeed

probable, as Eisig suggests, that certain dermal mucous organs have become incorporated

into the lateral line system. In his last Amia paper (1897, 6) Allis says (p. 627) : —

" In early stages of development they [i. e. canal organs and pit organs] closely resemble

* Ayers' views on the morphology of the semicircul;i,r canals compel him to take up the position that he does

(see particularly pp. 218-220;. Nevertheless I submit that tJicre is no Icuowii fact in the Jdstori/ of the lateral Jim

system tending to sJiow that there is any differentiation in the canals after thsy are once enclossd.

192 ME. F, J. COLE ON THE STRUCTUEE AND MOEPHOLOGY OF

each other, but in later stages they differ greatly, the pit organ retaining its embryo-

logical form and individuality, while the canal organ first increases greatly in size,

and then, by the independent growth of other similar organs immediately adjoining it,

gives rise to a large sensory patch, or nerve ridge (Merkel), in which the separate

organs lose to a greater or less extent their individuality." Again, on p. 629, lie

says : — " A line of pit organs represents ajoparently the possibility of a canal ; with

the disappearanee of the organs the possibility of the canal, even in rudiment, would

certainly disappear."

A striking fact in the comparative anatomy of the sensory canals that has hitherto

been overlooked is the relative abundance of the mucus secreted. Starting with the

Cyclostome fishes, we find most elaborate mucous organs and a very imperfectly developed

lateral line system. In Myxine the mucous sacs occupy the position of the lateral or

body canal in the higher fishes, and I think it must be agreed with Eisig and Dohrn

that these sacs represent very archaic structures which must have existed before the

lateral canal system itself. In the Elasmobranch fishes we get a condition ia which

mucous and sensory elements are combined, but in which the sensory elements as it were

have developed at the expense of the mucous elements. In other words there is a com-

bination of sensory and secretory cells, but the latter now exercise a subordinate (though

prominent) instead of a predominant function. Above the cartilaginous fishes the m.ucous

elements become more and more reduced, until the minimum is reached when tliey are

reduced to a few secretory cells at the base of each sense organ. Further, in the recent

TeleostSj the sense organs themselves are unmistakably reduced in number — in some cases

very considerably. The lateral sense organs were, as is well known, for a long time

regarded as secretory organs. On the discovery, however, of sense organs in the canals,

opinion veered romid to the other extreme, and completely ignored the undoubted

occurrence of glandular structures in the lateral canals and ampulhe. This is the further

surprising since the existence of such structures is to be expected. The other sense

organs of the head — the nose, the eye, and the ear — have all accessory glands connected

with them, and the physiological necessities of the lateral sense organs postulated the

existence of glandular cells liere also. Now the glandular organs ai)pcar to have played

at first a predominant, and then an accessory part in the history of the lateral

line organs, and it consequently follows that if they were at first predominant

they were also pre-existent and independent structures. There is therefore, in my

opinion, some justification for the view that the sensory and secretory portions of the

lateral line system were at first independent of each other, and that the incorporation of

the latter into the former necessarily followed on the adoption of the canal in preference

to the superficial type of sense organ. The rapidly evolving lateral line system, as it sank

below the surface, seized on the glandular organs and subordinated them to its own

use. But what is this use ? I think it is sufficiently obvious. From tlie structure and

consistency of the lateral canal mucus, it follows that it has considerably departed from

its original function of lubricating the surface of the body, and can no longer perform

that function. In the lateral canals it forms a delicate jelly, the "shivering" of which

agitates the sensory hairs and thus couvc) s a message from witiiout. It thus corresponds

precisely to the endolymph of the ear, is physiologically unnecessary in a superficial

THE CRANIAL NEKVES AND LATERAL SBN8E ORGANS OF FISHES. 193

sense organ, but became an obvious necessity when the superfical organs, increasing in

number, size, and sensitiveness, were sinking below tlie surface. The later process, whilst

it afforded the desirable protection to the sense organs, necessarily removed them further

from the sphere of their activity and demanded the physiological compensation supplied by

tlie introduction of mucus into tlie canals.

That the superficial type of sense organ preceded the central canal organ, or, in other

words, that tlie sensory canals arose jirimitively on the surface and then sank into their

usual subdernial position as definite canals, is to my mind amply proved both by fossil

Ichthyology and Emlnyology. The former shows us that in the most ancient fishes known,

such as the Ostracoderms, Artlirodira, and the older Sharks {Cladoselache, Cladodus), the

lateral canals existed as superficial grooves, which must therefore be held to be the most

primitive known condition. The development of the canals iu existing fishes is further

evidence in the same direction, and tells us that superficial grooves arise first by a

process of decentralisation, whilst the canals themselves are formed in segments after-

■viards /i/ situ. These two considerations enable us to form a general idea as to the

lines ujion which the lateral canals were laid down. Turning to the comparative

anatomy of the system, we can not only confirm the view suggested by the above evidence,

but are enabled to follow the process iu some detail. Whilst I fully concur in Lsydig's

contention previously mentioned, we may for the purposes of convenience classify the

lateral sense organs under three heads, as follows : —

/ (a) Pit organs sensu striclo, as iu Tcleosts. Most superficial.

(1) Superficial ij/pc ■! (b) Saviun vesicles [Torpedo] and nerve-sacks (Ganoids). lutermeJiati!

^ between 1 and 2.

(2) Intermediate type. AmpuUffi of Lorcnzini (Elasniohi'anchs).

(3) Central type. The canal sense organs (almost all fishes).

Here we have a continuous series connecting the superficial sense organs on the one

hand with the canal organs on the otlier, and indicating the manner in which the canals

and their organs may have been produced. In nearly all fishes the lateral line system is

in a very unstable condition. In Elasmobranchs the pit organs have sunk below the

surface, and have been converted either into Savian vesicles or ampulkB of L u-enzini,

principally the lattei', with the result that pit organs sensu stricto are largely absent.

In Teleosts, where Lorenzmian ampullae are absent, we find, as we should expect,

the pit organs on the surface, and existing in large numbers, perhaps as com-

pensation for the more or less reduction of the canal organs themselves. In Ganoids,

where the canal system, as far as our limited information goes, still flourishes,

the pit organs are comparatively few and have in some cases Ijcen converted into what

Merkel calls nerve-sacks. Iu many cases we find undoubted evidence of a canal in one

form being represented by a line of pit organs in another, showing tliat the latter

represent the possibility of a canal. Thus there seems to be a constant migration of

sense organs from the surface to the interior — a constant stream of superficial organs

inwards forming canals and organs in some cases and reinforcing them in others. It is

easy to see, for example, from what we know of the development of the canal organs, how

a line of ampuU-ae might form a canal. The insinking would only have to form a furrow

194 MR. F. J. COLE ON THE STEUCTUKE AND MOKPHOLOGT OF

instead of an ampuUary tube, and every condition for the development of a canal would be

satisfied, since the latter, as we know, is formed in segments. This brings us to the final

question as to whether the canals were originally formed as continuous furrows or by the

fusion of contio-uous pieces. On this point the evidence is unanimous and conclusive.

The comparative anatomy of the different classes of sense organs and canals, and

especially the development of tlie latter where known, prove beyond doubt that the

lateral canals were formed, not by the closure of continuous furrows, but by the fusion

end to end of adjacent tubes. The precise processes, as far as can be judged, would take

place in the following order : — (1) Formation of cords of indifferent cells along the lines

of the future canals ; (2) differentiation of sense organs along these cords ; (3) sinking

down of each sense organ to form a furrow, and the fusion of the lips of the furrow to form

a tube open at each end ; (4) fusion end to end of series of these tubes in such a way that

continuous canals are formed, and there is an opening on to the surface between each

two sense organs. Such, I believe, has been the phylogeny of the sensory canals, and

the question must now be left for further investigation either to substantiate or to

disprove this view.

S. The Lateral Sense Organs and the Auditory Organ.

Thomas Willis (1664, 224) may be said to have suggested the morphology of the

auditory organ to his better informed successors, when, in the same year that the

lateral line system was discovered, he described the auditory nerve as the dorsal branch

of the VIIth,and considered both nerves to constitute the seventh pair of cerebral nerves.

Leydig, however, was the first to derive the auditory organ from lateral sense organs

(1850, 120), but he unhappily recanted in 186S (126), and described the lateral

oro'ans as forming an organ of 6th sense, and having no morphological connection

with the auditory organ. In 1870 (182) Schulze, who erroneously thought that water

flowed through the sensory canals, regarded the latter as accessory auditory organs ;

whilst Dercum (1880, 59) went still further, and minutely compared the histology of the

lateral sense organs with the maculae of the ear, concluding that they resembled each

other in every essential respect. Emery (1880, 66), who agrees with Schulze that the

lateral organs represent an accessory auditory system, first discovered that the lateral

oro-ans possess a well marked cupula, which he believed to be foi'med of successive

cuticles secreted by the peripheral cells of the sense organ, and correctly compared with the

cupula terminalis of the ear. This important and interesting discovery has been extended

to several other forms besides Fiei^asfer, and I find a very well marked cupula in young

Gadus virens (see PL 23. fig. 4).

The important work by Mayser (1882, 135) is perhaps the first scientific contribution

to the question, and formed the basis upon which all further work was conducted. This

author discovered in Cyprinus that the fibres of the lateral line nerves and also the fibres

of tlie auditory nerve arose from a common centre in the brain — the tuberculum

acusticum. He was consequently led to regard the lateral line system as a low form of

auditory organ, and indted describes the lateralis lateral line nerve as the " hintere

THE CRANIAL NEEVES AND LATERAL SENSE ORGANS OF EiSilES. 195

Acusticuswurzel," and regards the semicircular canals as modified lateral tubes. I

entirely concur with Ayei-s that " Mayser was mucli nearer the truth tlian he ever

realised when he arrived at the conclusion above quoted " (7, p. 112). Mayscr's discovery

of the common origin of the two sets of fibres has been fully confirmed and also extended

by many subsequent authors, such as Strong, Kingsbury, and Herrick, so that it

must now be considered as an established fact. Bodenstein (1882, 24) briefly discusses

(p. 137) Mayser's conclusions, and largely concurs. He compares the semicircular canals

with the canals of the lateral line, and considers the endolymph of the ear to correspond

to the mucus in the lateral canals, but is somewhat inconsistent in regarding the

auditory organ as phylogenetically older than the lateral line system.

Beard (1884, 17) looked at the question irom a new aspect when, instead of regarding

the lateral system as an accessory auditory organ, and therefore discounting the value

of the comparison by im2:)lying that tlie two systems are only homoplastic and not

homologous structures, he derived the auditory organ from the lateral line system, and

concludes that '• the auditory organ of Vertebrates is fundamentally a specialised portion

of the system of sense organs of the lateral line." This view, that the ancestral Verte-

brate possessed a system of lateral sense organs which gave ri'^e lioth to the auditory organ

and to the modern lateral line system, has been abundantly supported by further

evidence, and now stands as one of the most probable views of vertebrate cephalogenesis.

Beard subsequently developed his hypothesis (1885, 19), and considered, with Gegeubaur,

Marshall, Balfour, and other embryologists, that the auditory nerve was a dorsal branch

of the facial.

In 1884, Wright (227) followed Bodenstein in comparing the endolymph of the ear

with the mucus in the lateral canals, and in a further publication in the same year (228)

independently confirms Mayser by describing a common origin in the brain for the

lateral line and auditory nerves of Amiurus. He, however, still perpetuated the mistake

of his predecessors in classing most of the lateral line nerves with the trigeminus, and

further states, what m.ust be regarded as doubtful, that the buccal nerve " contains fibres

other than those derived from the tuberculiim aciisticmn." Eisig (1887, 65) discusses

Beard's derivation of the auditory organ from lateral sense organs, and is favourably

disposed towards the view (pp. 711-712) ; whilst Fritsch (1887, 75), who was unable to

find a cupula to the lateral sense organs of Ilalaptenii-us, advances the extraordinary

explanation that it may have been washed away by the passage of sea water through the

canals.

The cousins Sarasin (1887, 177), who favour the derivation of the auditory organ from

lateral sense organs, and further consider that the latter function as accessory auditory

organs, enter into an elaborate comparison between the histology of the auditory and

lateral sense organs, and endeavour to establish that both are identical in all essential

respects. Cunningham (1890, 55), discussing the cupula of the lateral sense organs, is

" inclined to think the cupula is, during life, of a mucous nature, and therefore semi-liquid.

It seems certain that the sensory hairs are imbedded in the cupula. It is difficult to

understand how such cells as those of the sense organ should secrete mucus or form a

cuticle ; perhaps the cupula is nothing more than the ordinary mucus of the dermal tube,

SECOND StUlIES. — ZOOLOGY, VOL. VII. 27

196 MR. F. J. COLE O'S THE STRUCTURE AND MORPHOLOGY OF

which keeps a coustant position in prejoarations because it is retained by the numerous

sensory hairs " (p. 81). Here Cunningliam has overlooked the gland cells at the base of

the sense organ, which are doubtless responsible for the secretion of the cvipula. There is

therefore no necessity to suppose that it is secreted by sensory cells. Fritsch (1890, 77)

was again unable to find a cupula in the Torpedoes, but afte r careful investigation

admitted that the lateral sense organs agreed very closely in their minute histology with

those of the auditory organ.

In 1892 Ayers published his elaborate and important memoir on the morphology of

the vertebrate ear (7). In this work he endeavours to show that the cupuloe terminates

of the lateral and auditory sense organs are " artifacts produced in the main from the

auditory hairs of the sensory cells " (p. 314). He says (p. 163) : — " Now, while there is

no question that some mucus is present in all cases (all in which exact analyses have yet

been made), there is no evidence to show that in a state of nature it exists as a dome-

shaped mass covering the sense organ. On the other hand, it is clearly proven that the

most typical cupulae yet studied are products of the action of reagents, and that so far as

fibrous structures in the channels occupied by sense organs (whether car organs or those

of the lateral line system) are concerned, they have in every thoroughly studied case

shown themselves to be hairs more or less unchanged." I have previously referred to

the existence of cupuloe over the lateral sense organs as evidence that the latter and the

auditory organ are genetically related. Whether the cupulye are artifacts or not is a

question that does not affect this argument, since the conditions producing the artifact

must be the same in both cases, and the ai'tifact therefore open to be used in argument

as denoting equally important and similar conditions in both systems of sense organs. The

following quotations from Ayers' valuable monograph briefly summarise his line of

argument : — " The whole process of the formation of this [auditory] cup is an exact

repetition of the formation of a canal organ and its canal as seen in Amia, or tlie

formation of an ampulla and its canal in the Salmon " (p. 175). "There could not be a

more complete agreement between two developmental processes, occurring in diff^erent

animals, than there is between the formation of the canals on the surface of the body in

Amia and the formation of the canals of the internal ear in the Herring and Salmon, as

given by Von ISoorden. Of the correctness of the account for the latter I am certain, for

I have observed the same process both in the whole embryo and serial sections. From

uur present knoAvledge of the development of tlie labyrinth in the bony fishes we have

only agreement with the type of growth of the surface organs " (p. 181). " The so-called

semicircular canals develop as more or less curved structures, because they are formed

out of a portion of the external surface of the body, which has been enclosed within the

head. Since on the sxu-face of the body, in the typical and usual process of develojiment,

the canals always open at both ends on the surface, so inside the auditory vesicle they

open at both ends " (p. 222). " It is proven that there is no essential difference between

the sense organs of the internal ear of the vertebrate group and the superficial sense

organs of the Ichthyopsida as they exist in the surface canals of these forms. Both

consist of canals containing sense organs lying below the surface of the body, and they

may (as in ordinary canals and the ear in some Elasmobranchs) or they may not (as in

THE CR.\.NIAL NERVES AND LATERAL SEN.SE ORGANS OF FISHES. 197

Savi's vesicles [!] and the ear in the majority of Vertebrates) comrauuioate with the

surface. Both forms may or may not be entirely enclosed in cartilage or in bone. The

semicircular canals of the ear are simply remnants of the canal system of the surface,

and although bent into shapes more or less semicircular, they still retain their communi-

cation Avith the (morphological) exterior by means of their terminal (/. e. surface) pores

or ojaenings in the walls of the utriculo-sacculus, which in its turn often communicates

with the surface of the head by the endolymphatic duct or surface canal Thus it

is true that the develoi^ment of the semicircular canals in the ear is due to phylogeuetic

and mechanical causes, and is not in the least a response to physiological necessities or

requirements, and conversely the canals have no active part in the auditory function.

They serve merely as chambers to hold the liquid necessary to tloat the auditory sensory

hairs " (p. 308).

Ewart & Mitchell (1892, 69) remark (p. 100) :— " Restiug on the top of the hillock

there is often what Solger terms the ' Cujmlabildung.' This seems to consist of mucin.

In some cases we have seen long threads of mucin extending from the hillock into the

cupula or across the canal, the threads having frequently leucocytes entangled between

them." A similar condition of the cupula is described by Emery (18S0, 66). Willey

(189-4, 223) and Bashford Dean (1895, 58) agree that the auditory organ represents a

specialization of the lateral line system, and belongs to the same category as the sense

organs of the remainder of the lateral line. Locy (1895, 130) goes further, and regards

the ear, the nose, and probably the eyes as derived from the lateral line system, and states

on p. 51'7 that " there is now general agreement that the ears belong to tlie lateral line

series." Again, on p. 579, he says : — " The history of the auditory vesicle in sharks has

been worked out beyond this period by Ayers, and it is very clear from its mode of

growth that it is directly related to the canal organs of the lateral line." Finally, Miss

Piatt (1896, 158) remarks (p. 492): — "The ear has developed from the dorso-lateral

thickening in the hyobranchial intersegment, and it will be noticed that although the ear

undoubtedly belongs in [?to] the lateral line system, and is in fact the centre of that

system, it is not proj)erly a ' branchial sense organ,' as Beard suggests, for this term

cannot be acciu^ately applied to sense organs above the epibranchial line."

The general fact that the auditory organ is a modified portion of the lateral line

system must hence be considered established on a secure basis of fact, and it accordingly

follows that the lateral system of the ancestral Vertebrate must have existed before

differentiated sense organs, and then diverged in at least two directions (omitting

mention of the nose and eye, the phylogeny of wdiich is doubtful) — one producing the

lateral canals of recent fishes and the other the vertebrate auditory organ. The associa-

tion of the two sets of organs is completely justified on the evidence of the innervation

alone, since ]\Iayser and Strong have estal:)lished (1) that the lateral line and auditory

nerve fibres constitvite a system by themselves, and are quite independent of the other

cranial nerves ; (2) that this system arises from a common central origin in the brain,

which is farther distinct from the fibres of any of the other cranial nerves. The argument

from the nerves is well backed up by the argument from the minute structure and

development of the two series of organs, and I have already drawn attention to the fact

27*

198 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

that in both these respects (?'. e. histology and embryology) the agreement between the

lateral and auditory organs is so remarkable as to admit of only one explanation, and

that favourable to the close geuetic relationship of the two series. When, however,

we descend to details, and enquire into the phylogeny of the semicircular canals, the way

is not so clear. Ayers contends that a lateral line canal may differentiate further after

being cvit off from the surface. I have already joined issue with him on this point, and

have urged that there is no direct evidence favouring this statement. The lateral canals are

jirimitively laid down in the form they are found in the adult, and the only possibility of

svich differentiation is perhaps to be found in the blind diverticula of the canals described

by Hyrtl, Sappey, Pollard, the writer, and others. Ayers' postulate is by no means

impossible, but is at present mere speculation, and not founded on fact. The bearing

of this on the question of the semicircular canals is obvious. The latter develop as

evaginations of the wall of the auditory sac after the sac has become cut off from the

surface *, and is in a condition corresponding to a, lateral line canal. It is true that the

lumina of the semicircular canals are pieces cut off from the outside world, and one can

admire Ayers' comparison of a semicircular canal with a single segment of a lateral canal

still opening on to the surface (= cavity of sac) by its two terminal pores. These con-

siderations, and the others advanced by Ayers, do not discount the cardinal fact that the

semicircular canals of all Vertebrates develop in a way for which there is no jiarallel in

0 r knowledge of the anatomy and development of the lateral line system. At one time

1 thought that the ear with its semicircular canals was formed by a concentration of certain

lateral canals, and that the aqueeductus vestibuli or ductus endolyniphaticus corresponded

to a dermal tubule connecting an internal canal with the exterior. Both these contentions

are held and ably advocated by Ayers, and the latter undoubtedly holds good. The

question that remains is whether the auditory organ has arisen by the diflfereutiatioa of

an organ such as an ampulla of Lorenzini, or whether it was formed by the concentration

of certain primitive canals of the ancestral Vertebrate. In spite of the wealth of argu-

ment employed by Ayers, I cannot pass over the developmental difference described

al)ove, and must therefore hold to the former view, which by the way explains why there

shoiild be only one aquseductvis vestibuli in the history of the auditory organ. I thei-efore

follow Beard in regarding the ancestral auditory organ as represented by the primitive

auditory sac of the embryo, and that the semicircular canals arose later in the ancestral

history of the organ, and after it had entirely lost connection with the lateral line system.

Such a view of course involves the corollary that although the semicircular canals bear

many points of resemblance to the sensory canals of the lateral line, yet they must be

ren-arded as only homoplastic and not homologous Avith them. Ayers' view, on the other

hand, implies that the auditory organ was from the first a complicated structure and

possessed semicircvilar canals.

* [n some of the lower Vertebrates, of course, this never comjihteh/ bai)pens.

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 199

T. Special Considerations.

Schulze (1870, 182) was the first author to state that the lateral canals arose in

sections with a sense organ in each section, and that the dorsal tubules were formed by the

fusion of the adjacent extremities to form a single peripheral tubule and pore. This was

confirmed by Solger (1880, 193), Bodeustein (1882, 24), and AUis (1889, 4) — the latter's

work in tliis connection having been previously referred to. Friant (1879, 73) indepen-

dently discovered with Schwalbe that tlicre were two siqjerficial oplithalmic nerves, and

further has the credit of being the first author to approximately arrive at a correct

appreciation of the trigeminal and facial nerves of fishes, being the first writer to hold

that the superficial ophthalmic and l)uccal lateral line nerves were not branches of the

trigeminus*. He says (p. 103): — "Le nerf facial nait isolement des cotes du bulbe,

au-dessus de la racine posterieure du trijumeau, se distribue aux meninges, a la peau et

aux canaux muqueux du sommet de la tete et de la region sous-orbitaire, aux teguments

d'enveloppe de Freil et de I'orifice nasal, a la peau et aux teguments fibro-musculaires

du museau, aux muscles peaueiers de la joue, et chez la Perclie, a la jieau de la reo-ion

dorsale et aux muscles des nageoires dorsales." It will lie seen that for the time it was

written this was a very accurate description, and its historic imjjortance makes it

extraordinary that Friant's work should hitherto have been overlooked.

The fishes are classified by Sappey (1880, 175) into four groups according to the

development of tlie lateral line system : — (1) the Plagiostoma, in which it is greatest

developed ; (2) " L'Ange et les Squales," not so well marked ; (3) the majority of the

bony fishes, where it is more reduced than in 2 ; (1) fishes having no lateral line system

at all[!]. Such a classification, based on so very variable a structure (even though its

general anatomy is identical in nearly all fishes), is necessarily artificial, and has little or

no taxononiic value. It ^^■ould involve, for example, placing Jmia alongside Gadus.

Baudelot (1883, 16) states that the facial nerve is absent in many bony fishes {e.g. the

" Cariae ") and that in these forms it is represented by a branch of the trigeminus. Such

a statement must be due to imperfect observation, and if by " Carpe " we may under-

stand Cyprinus, a true facial nerve was described by several authors in that form long

before the time at which Baudelot was writing.

Sagemehl (1881, 172) emphasizes the fact that the two dorsal lateral canal commissures

are not homologous, and that a parietal commissure cannot be considered to represent

a supra-temporal commissure where in any genus the former is the only one found.

Eamsay Wright (1885, 229) considers (p. 491) that in Lepidosteiis a portion of the

R. oticus facialis represents the prsse-trematic or prge-s2)iracular branch of the facial,

since it supj)lies the anterior sense organ of the spiracular cleft, and states that a similar

condition is found in Amia. It is impossible that the two nerves mentioned can be

homologous, since the otic is a true lateral line nerve and cannot, therefore, be compared

with a nerve consisting of visceral sensory fibres. Wright, therefore, failed to find a

prae-spiracular nerve in Lepidosteus and Amia.

* Confirmed independently in 1881 by Marshall and Spencer, and in 1889 by Allis (4, pp. 513, 514).

200 ME. F. J. COLE ON THE STRUCTUKE AND MORPHOLOGY OF

Whilst on the subject of the facial nerve it is necessary that AUis's views on tliis nerve

in Amia should be discussed. He says (1897, 6, pp. 615, 616) : " After issuing from that

[=facial] canal the truncus facialis continues dowiiward, outward, and backward, lying

in the depression on the outer surface of the hyoniandibular, and separates almost

immediately into its two main j)ortious, the truncus mandibularis facialis and the

11. hyoideus facialis. The former lies anterior to the latter, turns downward, and soon

separates into its two portions, the 11. mandibularis exteruus facialis and the R. mandibu-

laris internus facialis." On p. 618 the "internal mandibular" is described as entering

into relations with the lower jaw. Before going further and discussing the homology of

the latter nerve with the chorda tynipani, it is necessary to point out that Allis has

misnamed his nerves. As I have already pointed out (18S)6, 46, p. 657 et neq.), the terms

internal mandibular and Jiijoidetis as first used by Stannius are not only synonymous hut

ap2)ly to a motor post-spiracular nerve related to the anterior face of the liyoid arch, just

as the pre-spiracvilar nerve should be related to the posterior face of the mandibular arch.

On this ground alone (and there are others) Allis's "iuternal mandibular" must be a

morphological pre-spiracular nerve, and as sucli is wrongly iiamed by him. As the

whole question, however, involves also the question of the homology of the chorda

tympani, it is first necessary to show what Allis's views are on the latter question. He

says (6, pp. 638, 639): "As the nerve [i. e. the "iuternal mandibular"!, in Amia, lies

behind the spiracular canal, it is a post-trematic branch of the facitilis, and cannot,

therefore, be the chorda tympani, for the course of that nerve in man through the upper

portion of the tympanic cavity and then downward anterior to that cavity certainly

indicates that it is a pre-spiracular nerve. That this nerve, in Amia, is the homologue

of the nerve of the same name described by Ewart, Pollard, and Strong, in other

Ichthyopsida, and considered by them as the homologue of the chorda tympani, is hardly

open to qitestion. The nerve in Amia is probably to be compared to the branch which,

on each side of the branchial arches, runs downward over the anterior face of the arch

on to the inner surface of its ventral portion. Its position in Amia, along the inner

surface of the mandible, could be easily derived from that in Selachians as given by

Vetter. In Heptanchus what seems to be the nerve is shown lying along the posterior

edge of the mandible ; tVom this position, as tlie hyoideo-mandibular fold of Amia was

formed, the nerve could as naturally come to lie along the inner sui-face of the mandible

as along the lateral surface of the hyoid." An examination of this passage reveals

several flaws. It is true that the chorda tympani is a pre-spiracular nerve,'as I have

previously shown (1896, 46), but is Allis's " iuternal mandibular " a pos^-spiracular

nerve ? We have seen that Ramsay Wright failed to identify the homologue of the

pre-spiracular in Lepidostens and Amia, and Allis himself (18S9, 4, \)\). 501 et seq.) says

nothing about it. The fact is, nothing is known of the relation of the "internal

mandibular" nerve of Amia to the spiracular cleft, since the embryonic condition hns

not yet been worked out, and the cleft itself degenerates in the adult. We are, therefore,

not in a position to say whether this nerve is pre- or post-spiracular. Further, what is

the definition of a pre-spiracular nerve ? It should fulfil three conditions : (1) it should

rim in frcmt of the spiracle : (2) it should pass akaig the posterior face of the mandibular

arch ; and (3) it should consist of visceral sensory fibres. With regard to the first

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 201

condition, there are several cases on record where on the disappearance of the spiracle the

pre-spiracular accompanies for a time the post-spiracular nerve and thus becomes a

topographical, but not a morphological, post-spiracular nerve. It seems to me that when

the early development of the nerves of Amia has been investigated it will be found that

the " internal mandibu.lar " nerve is morphologically pre-sj)iracular, though occupying a

post-spiracular position in the adult. This is what we know has happened in Raiia (cp.

Strong's " iuternal mandibular "), and what has douljtless also happened in Chliiiceni, and

Gadtis. The degeneration of the spiracular cleft naturally leaves the nerves unaffected,

since they ai'C concerned rather with the sensory and motor supjDly of the arches, and tli*;

latter are untouched by the disaj^pearance of the spiracle. With regard to the second

condition above, that is practically i'ulfilled, and so doubtless also is the third. The

"internal mandibular " nerve is certainly not a motor nerve in Amia, in which aise it

must be a visceral sensory nerve, and indeed AUis says tliat it " is distributed to the inner

surface of the liyoid and mandibular arches" (6, p. 745). The "internal mandibular"

nerve of Amia therefore is, as far as our knowledge of it goes, a morphological pre-

spiracular nerve, and in any case is excluded from l)eing the true internal mandibular

nerve, since this should be distributed to the muscles of the hyoid arch, and is undoubtedly

represented in Amia by the E-r. hyoideus and opercularis. In further criticism of the

passage quoted above I may remark that it is very much " open to question " that the

internal mandibular of Amia corresponds to the nerve of the same name described by

Ewart. The nerve of the latter author is a motor nerve partly to the muscles of the

hyoid arch, and as such differs essentially from the nerve in. Amia. The nerves described

b}' Pollard *, Gaupp (1893, 84), and Strong, are correctly homologised, Init should not

have been named "internal mandibular," as Miss Piatt (1890, 158, p. 534) and the

writer have pointed out. Finally, an anterior brancliial ramus is related to the posterior

and not to the anterior face of its arch, as Allis himself mentions is the cise with the

" internal mandibular " of Ilcptaiichus. Pinkus (1891, 157) introduces further confusion

into the synonymy of the facial nerve of fishes. He correctly homologises his " inferior

palatine VII " with the chorda tympani (but did not I'ecognize that this nerve represented

the pre-spiracular nerve of other fishes), and divides the morphological post-spiracular

nerve ( = , + the lateral line element, the hyomandilnilar trunk) into three parts—

(1) internal mandibular ; (2) hyoideus f ; and (3) motor Vllth. Pinkus is of course wrong

in using two synonyms (i. e. internal mandibular and hyoideus) to describe two different

branches, and it seems to me that 1 and 3 together represent the internal mandibular of

other fishes. The motor Vllth branches correspond undoubtedly to the ramus oper-

cvilaris facialis of the bony fishes.

There is hence some confusion in the terminology of the facial nerve of fishes, which it

is desira])le should be removed. I have therefore drawn up a scheme of the constitution

of the facial or Vllth cranial nerve in a typical fish, with the synonyms of the three

cardinal branches. It is to be hoped that future authors will, before naming a nerve,

first ascertain whether it is somatic or splanchnic, and then whether it is sensory or

■^ * See 1S92. 160, pp. '.VJl and :i9b (table). It will fie seen that Pollard's nerve is the one I have id(>ntified as

the chorda tympani in Gadtis.

f As this is a sensory nerve it must he unrepresented in other fishes.

202 MR. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

motor. I may mention here that there is a nerve in Gad us exactly corresponding to the

" internal mandibular " of Allis in Amia. I have for the above reasons described it as

the pre-spiracular or chorda tympani division of the facial. The following scheme of the

constitution of the facial nerve in a typical fish takes no account of the lateral line

constituent, which only accompanies the facial and is not a branch of it : —

Eacial nerve sensu stricto (minus external mandibular lateral line nerve). Forks over

spiracular cleft into —

(1) Palathnis or viscer alls facialis. Is joined by Jacobson's anastomosis (^palatinus

or visceralis glossopharyngei), and is a visceral sensory nerve distributed to

the mucous membrane of the roof of the mouth in front of the spiracle.

(2) A visceral sensory nerve arising from the base of (1) and forming part of the

same bundle of fibres. FrcB-spiracular, frce-hranchial, prcB-trcniatic, cr

chorda tjjnipani division of facial. May be continued ventrally on to pharynx,

in which case it should become related to the posterior face of the mandibular

arch, and be distributed to the mucous membrane of this arch.

(3) A visceral motor nerve = main trunk of facial. Forms external to spiracle a

portion of the nerve known as the truncus hyomandibularis facialis, of which

the remainder and larger part here=the external mandibular lateral line

nerve. JPost-spiracular, post-brancliial, post-tremafic, internal mandibular^ or

hyoidean branch of the facial. Continued ventrally on to pharynx, where it

becomes related to the anterior face of the hyoid arch, the muscles of which

absorb most of its fibres (Allis, 6, p. 745). Gives off posteriorly the nerve

known as the Ramus operctUaris facialis to the muscles of the hyoid arch

(Allis, loc. cit.).

Allis (4, p. 472), in seeking to prove the independence of the supra-orbital canal (which

is of course independent as far as innervation proves anything), goes somewhat too far

in advancing the developmental independence of the supra-orbital canal from the infra-

orbital as proving this point. As the lateral canals, according to his own description,

develop in indejiendent segments, each containing a sense organ, his argument proves

nothing, especially as there is a dermal tubule at the point of anastomosis between the

two canals which involves their independence as a developmental necessity. It will

have been noticed that I have not described an ophthalmicus profundus nerve in Gadus.

The question of the existence of this nerve in Teleosts is fully discussed by Allis (1897,

6, pp. 538 et seq.), and lie concludes : " In no Teleost, w^ith the single recorded exception,

so far as I can find, of Trigla, is there a sej)arate profundus ganglion and root. Both

ganglion and root are apparently always completely fused with the ganglion and root of

the trigeminus." He further points out that the nerve identified by Pollard as the

profundus in certain Siluroids is really the ophthalmicus superficialis VII, and, I think,,

rightly doubts any fusion between the profundus and superficialis as explaining the

apparent absence of the former, believing it to be " more probable that the ophthalmicus

profundus of Elasmobranchs is entirely wanting in Teleosts." Goronowitsch's and other

authors' nerves, therefore, named the ophthalmicus profundus, represent the ophthalmicus

superficialis V, and his ophthalmicus superficialis is the lateral line nerve of that name

THE CRANIAL NEEVES AND LATERAL SENSE ORGANS OF FISHES. 203

(1897, 90) *. In his later work (1897, 6, p. 625) Allis states, what I had previously-

suggested, that the so-called lateral line branch of the IXth of Amia is really a branch

of the lateralis lateral line nerve.

A rather curious mistake is made by Ayers (1892, 7), who describes the lateralis

latei-al line nerve as the "anterior (dorsal) branch of the IXth." Pollard makes a

statement which 1 had overlooked in my previous work, and which is closely paralleled

by the condition sometimes found in Chimcera {46, p. 616). He says (1892, 160, p. 395)

" In a young specimen of Poli/ptents about 20 cm. long, which was cut into sections'

there appeared to be a commissure from the ganglion of the trigeminus to the

ophthalmicus superficialis of the facial. The material was, however, not well preserved,

and consequently the existence of this commissure -which would represent the superficial

portion of the trigeminus could not be determined with absolute certainty." The buccal

and superficial oplithalmic lateral line nerves of Polypterus arise from a common trunk,

and the former accompanies the superior maxillary division of the Vth. Miss Piatt

(1896, 158) describes the IXth nerve of Necturiis innervating sense organs of the lateral

line, and considers the operculo-mandibular line of organs to be composed of two distinct

portions. Kingsbury (1897, 114) states that the lobi trigemini of Elasmobranchs and

Ganoids are directly homologous and constitute the lateral line centre, but that in

Teleosts tiie lobus trigeminus is another structure and belongs to the fasciculus communis

system. I had originally intended writing a section on the function of the lateral line

system, but this must be deferred for the present. In the meantime I may refer those

interested in the question to the works of Ayers (1892, 7), Dercum (1880, 59), Eritsch

(1888,76, and 1890, 77), Fuchs (1895, 78), de Sede (1885, 129), Ilichard (1896, 167),

Savi (184.4, 178), Stahr (1897, 196), (Willey 1891, 223), and Ramsay Wright (1884, 227).

Summary.

1 . The present communication contains the first description of the lateral sense organs

and their nerves in the genus Gadus.

2. The sensory canal system of Fishes, both recent and fossil, is resolvable into a

common type, to which the lateral canals of all forms can be reduced. This type

includes a lateral canal on the body, a canal over the eye, another underneath it, and

finally one related to the lower jaw. All these canals may be connected by median

commissures with their fellows of the opposite side.

3. The sensory canals of Gadus may be described as having diverged but slightly from

the typical form. The canal sense organs are somewliat reduced in number, which

involves a similar reduction in the dermal tubules. There are no Savian vesicles or

Lorenzini's ampuUse, but pit organs of the usual constitution are fairly common.

4. The lateral line systems ofGadusmorrhua and Gadus vii^ens exhibit specific differences.

5. The sensory canals, by their skeletal support, become secondarily related to the

* He says (p. 30) : " Der N. ophth. superf. ist wie bei Knochenfisclieu ein Ast des Trigeminus II. [=lateral line

component]. Der N. ojihthahnicus jirofinidus von Acipenser ist aiisschlie^slich cin Ast des Trigeminus I. tiiid ist

dcninach kein uoUl-ommeiics ffomoloijoii des (flcichiiamii/en Nervcii voa Lota, wcleher FAemcnte des Facialis ciUhdJi. Der

R. oticus ist boi Acipenser oin Ast des Facialis und des Trigeminus II. und kanu demnach aucb iiicht mit dem N.

ophthalmicus prof, der Knochentischc direkt vergiichen wcrden."

SECOND SEUIES. — ZOOLOGY, VOL. VII. 28

204 ME. F. J. COLE ON THE STEUCTUEE AND MOEPHOLOGY OF

skeleton of the head, and on their disappearance left a legacy to the skull in the shape

of certain of the lateral line ossicles, which either on account of additions to their

original function were retained as new elements, or were fused on to, and came to form

a part of, hones previously existing.

6. The ganglia of the trigeminal and facial nerves have fused to form an elaborate

complex, in which the individuality of the ganglia has been lost, and which arises from

the brain by two roots. The ganglion in connection with the lateral line nerve is,

however, distinct. The sympathetic trunk is connected with the vagu.s, glossopharyngeal,

and trigemino-facial ganglia.

7. A portion of the trigemino-facial complex which is connected with visceral

sensory fibres, and which I have called the facial ganglion, is in such a condition as to

strongly suggest the view that it is migrating from the complex and is in process of

being converted into a sympathetic ganglion. It is in connection with the sympathetic

trunk, and has been described by many authors as a symjiathetic ganglion. The

condition of this ganglion favours the view that at least the greater part of the facial,

glossopharyngeal, and vagus nerves of Fishes belongs to the sympathetic system.

8. A typical branchial nerve has the constitution tabulated on p. 144.

9. The facial nerve of Man and Mammals can be derived from the branchial facial

nerve of a fish.

10. The anastomosis of Jacobsou is the visceral sensory palatine or visceral branch of

the IXth, and connects the glossopharyngeal ganglion with the ramus palatiuus facialis

(also visceral sensory). It is neither a somatic sensory nor a lateral line anastomosis, and

cannot be homologiscd with either of these.

11. The lateral line system of Fishes is, as far as our present knowledge goes, not

metameric. This conclusion is supported by the whole of the anatomical and part of the

embryological evidence. The observations under the latter head that have hitherto been

considered to support the metameric view of the lateral organs are certainly in part, if

not entirely, concerned with another series of sense organs, and do not relate to the

lateral sense organs at all.

12. The nerves supplying the lateral sense organs (both superficial and canal) form a

separate series in themselves, and are not connected with any of the other cranial nerves ,

They may be named the Superficial Ophthalmic, Buccal, External Mandibular, and

Lateralis Lateral line Nerves. The innervation of the lateral sense organs of Fishes and

Amphibia is remarkably constant, and should be taken as the guide in determining the

limits of a canal. The sensory canals and pit organs of Gadiis are innervated by the

branches of these nerves — the glossopharyngeus taking no part in the innervation of the

system either in Gaclus or morphologically in any other form.

13. The system of nerves known as the ramus lateralis trigemini is a ganglionated

system of somatic sensory nerves formed typically of the dorsal branches of the Vth,

Vllth, IXth, and Xth cranial nerves, with a certain number of the same branches of the

spinal nerves, all more or less fused together, and forming the sensory nerve supply of all

the fins of the body. Its common name, therefore, should be abandoned in favour of its

oriu'inal name of ramus lateralis accessorius.

I

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 205

14. The so-called lateralis nerve of Fetromyzon is not a lateral line nerve at all, but its

anatomy sliows it to belong vindoubtedly to the lateralis acccssorius system.

15. The lateral line system of Gadus is in remarkable agreement with that of Ainia,

except that the latter form exhibits less reduction in the number of its sense organs.

16. The sense organs of the lateral line of Pishes and Amphibia are not lioiuologous

■with the lateral sense organs of Annelids {e. g. Ca})itellidte).

17. The sensory canals were probably represented in the ancestral Vertebrate by non-

segmental sujierficial sense organs. These sank below the sui-face, forming a series of

tubes, by the end-to-eud fusion of which the sensory canals were formed. As the sense

organs sank below the surface, certain lateral glandular organs were also included which

secreted the mucus tilling the canals. These glands have been subsequently much

reduced in importance, and their function now is an accessory one, l. e. to secrete a

substance corresponding precisely to the endolympli of the ear. Before the sensory canal

system extended forwards and backwards it was probably confined to the region now

occupied by the auditory organ.

18. There can l)e little doubt that the primitive lateral line organs gave rise both to

the recent lateral system and also to the vertebrate auditory organ. It is doubtful

whether the semicircular canals have arisen by a concentration of primitive sensory

canals or by the decentral development of a primitive simple sac. The author holds to

the latter view, and believes that the semicircular <*.anals are homoplastic and not

homologous with tiie sensory canals.

19. The author's previous view that the chorda tympani nerve of Mammals has been

derived from the prae-spiracular division of the facial of the Piscine ancestor of the

Vertebrates is confirmed. The nerve referred to as the " internal mandibular " by Allis

and some other authors is wrongly identified, and is really the prae-branchial or chorda

tympani division of the facial.

20. A typical facial nerve of a fish has the constitution tabulated on p. 202.

Zoological Department,

University College, Liverpool.

March 2ud, 1898.

Postscri2)t. — Since writing Section H, I have examined a large number of Gad/is skulls,

and have no doubt now that the description does not represent the normal condition, which

in the vast majority of the specimens examined was that of complete fusion between the

dermal and cartilage pterotic elements, although the point of fusion could always be easily

detected. The nomenclature of these two l)ones is lience in urgent need of revision.

The terms post-frontal and squamosal should be reserved for the separate dermal lateral

line elements, and sphenotic and pterotic for the separate cartilage auditory bones. A

comj)ound term is also necessary for the condition in which the lateral and cartilage

elements have secondarily fused to form one bone. Where the lateral line bones are never

known to be separate from the underlying cranial bones in the adult there is no pressing

need in the meantime for any revision of the nomenclature. — Sept. 27, 1898.

28*

206 MR. r. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

Preliminary Bibliography *.

1. Ahlborn, F. — " Untersuchuiigen iiber das Gehirii der Petromyzonten," Zeits. f. wissen. Zool.,

Bd. xxxix. pp. 191-294., Taf. xiii.-xvii., 1883.

Theil I. published as an inaugural dissertation, pp. 1-47, Leipzig, 1883.

2. Ahlborn, F. — " IJbor den Ursprung und Austritt der Hirnnerven von Petromyzon," u. " tJber die

Segmentation des Wirbelthierkilrpers," Zeits. f. wissen. Zool., Bd. xl. pp. 286-330, Taf. xviii.,

1884.

3. Alcock, B.— " The Fifth Pair of Nerves," in Todd's ' Cyclopaedia of Anatomy and Physiology,'

vol. ii. pp. 268-310, London, 1839.

4. Allis, E. P., Jr. — " Tlie Anatomy and Development of the Lateral line System in Amia calva,"

Jour, of Morphology, vol. ii. pp. 463-566, pi. xxx.-xlii., 1889.

5. Allis, E. P., Jr. — " The Cranial Muscles and Cranial and First Spinal Nerves in Amia calva," Jour.

of Morphology, vol. xi. pp. 485-491, 1895.

Preliminary to 6.

6. Allis, E. P., Jr. — " The Cranial Muscles and Cranial and First Spinal Nerves iu Amia calva," Jour.

of Morphology, vol. xii. pp. 487-808, pi. xx.-xxxviii., 1897.

7. Ayers, H. — " Vertebrate Cephalogenesis. II. A Contribution to the Morphology of the Vertebrate

Ear, with a Reconsideration of its Functions," Jour, of Morphology, vol. vi. pp. 1-360, pi. i.-xii.

1892.

8. Baer, K. E. von. — " Uebcr den Seiteukanal des Stiirs," Meckel's Archiv f. Anat. u. Physiol. T. ix.,

pp. 376 and 377, Jahr. 1826.

9. Balfour, F. M. — " A Treatise on Comparative Embryology." Vol. ii. Vcrtebrata, pp. 443-446,

London, 1881.

10. Bateson, W. — " The Sense Organs and Perceptions of Fishes ; with Remarks on the Supply of Bait,"

Jour. Marine Biol. Assoc. United Kingdom, vol. i., n. s. pp. 225-256, pi. xx., 1889-90.

1 1 . Baudelot, E. — " De la Determination homologique d'une Branche du Nerf pathetique chez le Merlan

[Gaelics merlangus]," Bull, de la Soc. des Scien. Nat. de Strasbourg, Ann. i. pp. 81-83, 1868.

* Tho above list simply oontains those papers consulted by the author in writing the present work. A complete

Bibliography of the anatomical, enibryological, physiological, recent and fossil literature, directly or indirectly treating

of the Brain, Cranial Nerves, and Lateral Sense Organs of Fishes and Amphibia, is iu active preparation, and will be

publislied separately. Nevertheless, although the present list has already been more than doubled, the author would

be extremely grateful for any references not included in it, either to the sender's own papers, or to any others which

should have been recorded. The objects of the forthcoming Bibliography (by no moans a mere list) are : (1) to

provide an absolutely complete and accurate catalogue of all the works ever published more or less relating to the

subject; (2) to be a guide to an author (by means of abstracts, indexing, &c.) newly taking up the subject to the

literature immediately affecting his sjtecial purpose, and also to those general works it were expedient that he should

consult ; (3) to supply the pressing need of an Index Expur(jatorius, With regard to the latter, and perhaps most

important, object, it is obvious that an author, however conscientious, cannot be expected (unless, indeed, he is

writing an extensive monograph) to wade through at least 700 papers before writing his own. It is equally obvious

that many of these papers, either on account of the antiquity of their contents, or other equally potent but less

excusable reasons, may very well be consigned to the " silent tomb," and piously allowed to remain there. The want

of such an analytical Bibliography has, even in the confined experience of the author, over and over again imjjaired

an otherwise useful piece of work. It is respectfully hoped, tliercfore, that a diligent and unprejudiced search

through the literature will have the general effect of clearing the air, and thus proving of some service to those

subsequently taking up the work.

THE CRANIAL NERVES AND LATEEAL SENSE ORGANS OF FISHES. 207

12. Baudelot, E. — " Considerations sur le Tronc Lateral du Pneumogastrique chez les Poissons," ibid.,

pp. 109-112, 1868.

13. Baudelot, E. — "Observation relative :i une Branche anastomotique des Nerfs trijumeau et pneumo-

gastrique cliez le Merlan [Gadus merlangus]," ibid., pp. 114-116, 1868.

14. Baudelot, E. — " Observation sur les Origines de la Branche operculaire du Nerf lateral du

Pneumogastrique cliez quelques Poissons," ibid., Ann. ii. pp. 22-24, 1869.

15. Baudelot, E. — " Etude sur I'Anatomie comparee de I'Encepbale des Poissons," Mem. de la Soc.

des Sci. Nat. de Strasbourg, t. vi. livr. ii. pp. 51-128, plan, i., 1870.

16. Baudelot, E. — ' Recherches sur le Systeme nerveux des Poissons,' pp. 1-178, pi. i.-x., Pans,

1883.

Reviewed by E. Dubrueil in Revue d. Sci. Nat. (Montpellier), ser. iii. t. iii. pp. 633-638, 1883-84.

17. Beard, J. — "On the Segmental Sense Organs of the Lateral Line, and on the Morphology of the

Vertebrate Auditory Organ," Zr)ol. Anz., Jahr. vii. pp. 123-126, 140-143, 1884.

Preliminary to 19.

18. Beard, J. — "On the Cranial Ganglia and Segmental Sense Organs of Fishes," Zool. Anz. Jahr., viii.

pp. 220-223, 1885.

Preliminaiy to 19.

19. Beard, J. — "The System of Branchial Sense Organs and their associated Ganglia in Ichthyopsida.

A Contribution to the Ancestral History of Vertebrates," Q. J. M. S. n. s. vol. xxvi. pp. 95-156,

pi. viii.-x., 1885-6.

20. Beard, J. — "The Ciliary or jNIotor-oculi Ganglion and the Ganglion of the Ophthalmicus Profundus

in Sharks," Anat. Anz. Jahr. ii. pp. 565-575, 1887.

21. Beard, J. — "Morphological Studies. II. The Development of the Peripheral Nervous System of

Vertebrates. Part 1. Elasmobranehii and Aves," Q. J. M. S., n. s. vol. xxix. pp 153-227,

pi. xvi.-xxi., 1888.

22. Beck, B. — " Anatomische Untersuchungen iiber einzelne Theile des VII. und IX. Hirnnerven-

paares," pp. 1-69, Taf. i.-iii., Heidelberg, 1847.

23. Bendz, H. — "Bidrag til den sammenlignende Anatomic af Nervus glossopharyngeus, vagus,

accessorius Willisii og Hypoglossus hos Reptilierne," Det K. Danske Videns. Selsk. Naturv.

og Math. Afhand. Deel x. pp. 113-152, Tab. i.-x., 1843.

24. BoDENSTEiN, E. — " Dcr Seiteukanal von Cotitts gobio," Zeits. f. wissen. Zool., Bd. xxxvii. pp. 121-

145, Taf. X., 1882. See criticism by B. Solger, " Bemerkung iiber die Seitenorganketten der

Fiscbe," Zool. Anz., Jahr. v. pp. 660-661, 1882.

25. Boll, F. — " Die Lorenziui'scheu Ampullen der Selachier," Archiv f. mikros. Anat., Bd. iv. pp. 375-

391, Taf. xxiii., 1868.

26. Boll, F. — " Uber die Savi'schen Bliischen von Torpedo," Monats. der Konig. Preuss. Akad. der

Wissens. zu Berlin, Jahr. 1875, pp. 238-241, 1876.

Preliminary to 27 and 28.

27. Boll, F. — " Le Vescicole di Savi della Torpedine," Atti della R. Accad. dei Lincei, ser. ii. vol. ii.

pp. 385-392, tav. i., 1875.

See German translation below (28).

28. Boll, F. — " Die Savi'schen Blaschen von Torpedo," Archiv f. Anat. Phys., u. wissen. Medicin,

pp. 456-468, Taf. xi., 1875.

Identical with the Italian memoir (27).

29. Bonnier, P. — See J. Richard (167).

30. BoNSDORFF, E. J. — " Disquisitio Anatomica, Nervum trigeminum partemque cephalinam Nervi

sympathici Gadi Lotae, Linn., cum nervis iisdem apud Hominem et Mammalia comparans,"

pp. 1-52, tab. i., Helsingforsise, 1846.

208 ME. F. J. COLE ON THE STKTJCTUEE AND MORPHOLOGY OF

31. BoNSDOKFF, E. J. — "Symbolic ad Anatomiam compai-atam Nervorum Animalium vertebratorum/J

Nervi cerebrales Coni cornicis (Linn.)," Acta Soc. Sci. Fennicic, t. iii. pp. 505-569, pi. vi.-vii.,

1852.

32. BoNSDORFF, E. J. — Ibid., " 11. Ncrvi cerebrales Grids cinerece, Linn.," ibid., pp. 591-624, pi. x.,

1852.

33. BoNSDOEFF, E. J. — "Jemfcirande anatomisk Beskrifning af Cerebral Nerverna hos Raja clavata"

Acta Soc. Sci. Feunicse, t. v. pp. 1X5-227, tab. ii.-iv., 1856.

34. Bridge, T. W.- — " On the Morphology of the Skull in the Paraguayan Lepidosiren and in other

Dipnoids," Trans. Zool. Soc. London, vol. xiv. part v. pp. 325-376, pi. xxviii.-xxix., 1898.

35. Brinton, W. — " The Seventh Pair of Nerves," in Todd's ' Cyclopaedia of Anatomy and Physiology/

vol. iv. pp. 543-556, Loudon, 1852.

36. BtJCHNER, G. — " Meoioire sur le Systeme nerveux du Barbeau (Cyprinus barbus, L.)," Mem. de la

Soc. du j\[us. d'Hist. nat. de Strasbourg, t. ii. pp. 1-57, plan i., 1835.

37. Bunker, F. S. — " On the Structure of the Sensory Organs of the Lateral Line of Ameiurus nebulosus,

Le Sueur," Anat. Anz., Bd. xiii. pp. 256-260, 1897.

38. BuRCKHARDT, li. — " Das Ceutralncrvensystem von Protopterus annectens. Einc vergleichend-

anatomische Studie," pp. 1-64, Taf. i.-v., Berlin, 1892.

39. BuRCKHARDT, E. — " Beitrag zur Morphologic des Kleiuhirns dcr Fische," Archiv f. Anat. u. Phys.,

Anat. Abth., Supplementband, pp. 111-136, Taf. vii., 1897.

40. Chevrel, R. — " Sur le Systeme nerveux grand sympatbique des Poissons osseux/' Comp. Reud.

Acad, des Scien. Paris, t. cvii. pp. 530-531, 1888.

Preliminary to 41.

41. Chevrel, E. — "Sur TAnatomic du Systeme nerveux grand sympatbique des Elasmobranches et des

Poissons osseux," Arch, de Zool. Exper. et Gen., ser. ii. t. v. bis, Mem. v. pp. 1-196, pi. i.-vi.,

1887-90. Published as separate volume, Poitiers, 1889, and Paris, 1891.

See abstract. Rev. Scientif. ser. iii. t. xvi. ( = t. xlii.), p. 409, 1888.

42. CoGGi, A. — " Le Vescicole di Savi egli Orgaiii della Linea lateraie nellc Torpedini," Atti d. E. Accad.

dei Lincei, Eendiconti, vol. vii. ser. iv. pp. 197-205, 1891.

See French translation below (43). Reviewed by S. Gai'man, ' Science,' vol. xix. p. 128, 1892.

43. CoGGi, A. — " Les Vesicules de Savi et les Organes de la Ligne lateraie cbez les Torpilles," Arch.

Italiennes de Biologic, t. xvi. pp. 216-224, plan, i., 1891.

Identical with the Italian memoir (42).

44. Cole, F. J.— "The Cranial Nerves of Chimmra monstrosa," Proc. Roy. Soc. Edinburgli, vol. xxi.

pp. 49-56, 1896.

Preliminary to 46.

45. Cole, F. J. — " On the Sensory and Ampullary Canals of Chimara," Anat. Anz., Bd. xii. pp 172-

182, 1896.

Criticism of 54.

46. Cole, F. J. — " On the Cranial Nerves of ChimcBra monstrosa (Linn., 1754) ; with a Discussion of

the Lateral line System, and of the Morphology of the Chorda tympani,'' Trans. Roy. Soc.

Edinburgh, vol. xxxviii. pp. 631-680, pi. i.-ii., 1896.

46 a. Cole, F. J. — " Reflections on the Cranial Nerves and Sense Organs of Fishes," Trans. Liverpool

Biol. Soc., vol. xii. pp. 228-247, 1898.

47. CoLLiNGE, W. E. — "Note on the Lateral Canal System of Polypterus," Proc. of the Birmingham

Philos. Soc, vol. viii. pp. 255-263, pi. i.-iii., 1891-93.

48. CoLLiNGE, W. E. — " The Lateral Canal System of Ltpidusteus osseus," ibid., pp. 263-272, pi. iv.-ix.,

1891-93.

49. CoLLiNGE, W. E. — " The Sensory Canal System of Fishes. Part I. — Ganoidei," Quart. Journ.

Micros. Soc, n. s. vol. xxxvi. pp. 499-537, pi. xxxix.-xl., 1894.

THE CRANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 20i)

50. CoLLiNGE, W. E. — " On the Sensory Canal System of Fishes/' Report British Assoc. Nottingham,

pp. 810-811, 1894.

51. CoLLiNGE, W. E. — '•■ The Morphology of the Sensory Canal System in some Fossil Fishes," Proc. of

the Birmingham Nat. Hist, and Philos. Soc. vol. ix. pp. 58-70, pi. i.-ii., 1894-95.

52. CoLLiNGE, W. E. — " Some Researches upon the Sensory Canal System of Ganoids," ibid., pp. 77-83,

1894-95. Abstract of work previously published.

53. CoLLiNGE, W. E. — " On the Sensory Canal System of Fishes. Teleostei — Suborder A, Physo.itomi,"

Proc. Zool. Soc. London, pp. '271—299, pi. xviii.-xxi., year 1895.

54. CoLLiNGE, W. E. — "On the Sensory and Ampullary Canals of C/dmcera," Fvoe. Zool. Soc. London,

pp. 878-890, pi. li.-liii., year 1895.

55. Cunningham, J. T. — "A Treatise on the Common Sole (Solea vw/jram), considered both as an

Organism and as a Commodity," pp. 1-147, pi. i.-xviii., Plymouth, 1890.

56. CuviER, G.— ' Lecons d'Anatomie comparee,' t. ii. pp. 166-172, 193-242, Paris, 1799.

57. CuviER, G., & V.iLENCiENNEs, A. — '• Illstoire naturelle des Poissons," t. i. pp. 415-445, plan, iv.-vi.,

1828 ; also t. v. plan, cxl., Paris, 1830.

58. Dean, Bashforu. — ' Fishes, Living and Fossil. An outline of their Forms and probable Relation-

ships,' Nevi' York and London, 1895.

59. Dercum, F. — "The Lateral Sensory Apparatus of Fishes," Proc. of the Acad, of Nat. Sei. of

Philadelphia, year 1879, pp. 152-154, 1880.

60. Desmoulins, a., & Magendie, F. — " Anatomic des Systemes nerveux des Animaux a vertebres,

appliquee k la Physiologic et a la Zoologie," part i.-ii.. Atlas, plan, i.-xiii., Paris, 1825.

61. DixoN, A. F. — " On the Development of the Branches of the Fifth Cranial Nerve in Man," Sci.

Trans, of the Roy. Dublin Soc, ser. ii. vol. vi. pj). 19-76, pi. i.-ii., 1896.

62. DoHRN, A. — " Studieu zur Urgeschichte des Wirbelthierkorpers. XIIL Uber Nerven und Gefasse bei

Ammoca'tes und Petromyzon planeri," Mittheil. a. d. Zoolog. Stat, zu Neapel, Bd. viii, pp. 233-

306, Taf. x.-XT., 1888.

See C. JuLiN (i 08-1 12).

63. DuBRUEiL, E. — See E. Baudelot (16).

64. EisiG, H. — " Die Seitenorgane und becherformigen Organc der Capitelliden. Zweiter Auszug aus

einer Monograpliie der Capitelliden," Mittheil. a. d. Zoolog. Stat, zu Neapel, Bd. i. pp. 278-

342, Taf. vii., 1878-79.

Preliminary (in part) to 65.

65. EisiG, H. — " j\ionographie der Capitelliden des Golfes von Neapel und der angrenzenden Meeres-

abschnitte, uebst LIntersuehungen zur vergleiclienden Auatomie und Pliysiologie," Fauna u.

Flora d. Golf. v. Neapel, xvi. Monographic, Berlin, 1887.

66. Emery, C. — " Le Specie del Genere Fierasfer nel Golfo di Napoli e Regioni limitrofe," Fauna u.

Flora d. Golf. v. Neapel, ii. Monographic, pp. 1-76, tav. i.-ix., Leipzig, 1880.

67. EwART, J. C. — " On the Cranial Nerves of Elasmobrauch Fishes. Preliminary Communication,"

Proc. Roy. Soc. London, vol. xlv. pp. 524-537, 1888-89.

68. EwART, J. C. — •" The Lateral Sense Organs of Elasmobrunchs. I. The Sensory Canals of Lmmargus,"

Trans. Roy. Soc. Edinburgh, vol. xxxvii. pp. 59-85, pi. i.-ii., 1892.

See abstract, Zool. Anz., Jahr. xv. pp. 116-118, 1892.

69. EwART, J. C, & Mitchell, J. C. — ■" On the Lateral Sense Organs of Elasmobranclis. II. Tlie

Sensory Canals of the Common Skate (Raja batis)," Trans. Roy. Soc. Edinburgh, vol. xxxvii.

pp. 87-105, pi. iii., 1892.

See abstract, Zool. Anz., Jahr. xv. jjp- 118-120, 1892.

70. EwART, J. C. — " Supplementary Note on the Cranial Nerves of Elasmobranchs," in " Papers on

Electrical and Lateral Seu'^e Organs and on the Cranial Nerves of Elasmobranchs," No. 9,

pp. 1-3, Edinburgh, 1893.

210 ME. F. J. COLE ON THE STRUCTUEE AND MOEPHOLOGY OF

71. EwART, J. C.J Se Cole, F. J. — "On the Dorsal Branches of the Cranial and Spinal Nerves of

Elasmobranchs/' Proc. Roy. See. Edinburgh, vol. xx. pp. 4.75-480, 1895.

72. Fee, F. — " Recherclies siir le Systeme lateral du Nerf Pneumo-gastrique des Poissons," Mem. de la

Soc. des Sci. Nat. de Strasbourg, t. vi. livr. ii. pp. 129-201, plan, i.-iv., 1870.

73. Friant, a. — " Recherches anatomiques sur les Nerfs Trijumeau et Facial des Poissons Osseux,"

Bull. d. 1. Soc. des Sci. de Nancy, ser. ii. t. iv. fasc. ix. pp. 1-1U8, plan, i.-vi., 1879. Also

published as separate volume, Berger-Levrault et Cie., Nancy, 1879.

74. FiiiTSCH, G. — ' Uutersuchungen iiber den feiueren Bau des Fischgehirns, mit besonderer Beriick-

sichtigung der Homologien bei anderen Wirbelthierklassen,' pp. 1-91, i.-xv., Taf. i.-siii.,

Berlin, 1878.

75. Fritsch, G. — 'Die elektrischen Fische. Erste Abtheilung, Malopterurvs electricus,' pp. 1-90,

Taf. i.-xii., Leipzig, Veit & Comp., 1887.

76. Fritsch, G.— " Uber Bau und Bedeutung der Kanalsystemc unter der Haut der Selachier," Sitz. d.

Konig. Preuss. Akad. der Wisseu. zu Berlin, Halbbd. i. pp. 273-306, Jahr. 1888.

Reprinted and expanded in 77.

77. Fritsch, G. — ' Die elektrischen Fische. Zweite Abtheilung, Die Torpediueen,' pj). 1-1 16, Taf. i.-xx.,

Leipzig, 1890.

78. FccHS, S. — " Ueber die Function der unter der Haut licgeuden Caualsysteme bei den Selachiern,"

Pfluger's Archiv f. d. ges. Phys. d. Mens. u. d. Thicre, Bd. lix. pp. 451-478, Taf. vi., 1895.

Reviewed by F. Schenck, Zool. Central., Jahr. ii. i)p. 120-121, 1895.

79. FiJRBiNGER, M. — "Ueber die spino-occipitalen Nerven der Selaehier und Holocephalen und ihre

vergleicheude Morphologic," in Festschrift liir Gegenbaur, Bd. iii. pp. 349-788, Taf. i.-viii.,

Leipzig, 1897.

80. Garman, S. — " On the Lateral Canal System of the Selachia and Holoccphala," Bull. Mus. Comp.

Zool. Harvard, vol. xvii. pp. 57-119, pi. i.-liii., 1888-89.

81. Garman, S. — See A. Coggi (42).

82. Gaskell, W. H. — "On the Structure, Distribution, and Function of the Nerves which innervate

the Visceral and Vascular Systems," Jour. Pliys., vol. vii. pp. 1-80, pis. i.-iv., 1886.

8'?. Gaskell, W. H. — "On the Relation between the Structure, Function, Distribution, and Origin of

the Cranial Nerves ; together with a Theory of the Origin of the Nervous System of Vertebrata,"

Jour. Phys., vol. x. pp. 153-211, pis. xvi.-xx., 1889.

84. Gaupp, E. — " Beitriige zur Morphologie des Schiidels. — I. Primordial-Cranium und Kieferbogen

von Ra/ia fusca," Schsralbe's Morph. Arbeiten, Bd. ii. pp. 275-481, Taf. xiii.-xvi., Jena,

1893.

85. Gegenbaur, C. — " Ueber die Kopfnerven von Hexanchus und ihr Vcrhaltniss zur ' Wirbeltheorie '

des Schiidels," Jen. Zeits. f. Med. u. Natur. Bd. vi. pp. 497-559, Taf. xiii., 1871.

86. Gehuchten a. van. — " Contribution a I'Etude du Systeme uerveuxdes Tel^osteens. Communication

preliminaire," La Cellule, t. 10, pp. 253-295, plan, i.-iii., 1894.

87. GiLTAY, C. M. — " tiuseritur Descriptio ueurologica Esocis Lucii, figuris illustrata et cum reliquis

vertebratis animalibus, prsesertim quod ad cerebrum et uervos encephali attinet, comparata,"

Comment, ad Qusest. Zool., ab ord. discip. Math, et Phys. in Acad. Lugduno-Batava, pp. 1-59,

tab. i.-v., Leyden, 1832.

88. GiLTAY, C. M. — " Dissertatio anatomico-physiologica inauguralis de Nervo sympathico," pp. 1-165,

tab. i.-ii., Lugduni Batavorum, 1834.

8q. Goronowitsch, N. — " Das Gehirn und die Cranialnerven von Acipenser ruthenus," Morphol. Jahrb.,

Bd. xiii. pp. 427-454, Taf. xvii.-xxiii., 1887-88.

90. Goronowitsch, N. — " Der Trigemino-facialis-Koniplex von Lota vulgaris," in Festschrift fiir

Gegenbaur, Bd. iii. pp. 1-44, Taf. i.-ii., Leipzig, 1897.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 211

91. GuiTEL, F. — " Sur le Systeme de la Ligne laterale des Lepadogasters/' Comp. Rend. Acad, des

Scien. Paris, t. cv. pp. 687-690, 1887.

92. GuiTEL, F. — " Sur les Canaux muqueux des Cyclopterides," ibid. t. cix. pp. 648-651, 1889.

93. GuiTEL, F. — " Sur la Ligue laterale de la Baudroie [Lophius piscatorius, h.)," ibid. t. ex. pp. 50-52,

1890.

Preliminary to 95.

94. GuiTEL, F. — " Sur le Nerf lateral des Cyelopterides," ibid. t. cxi. pp. 536-539, 1890.

95. GuiTEL, F. — " Recherches sur la Ligne laterale de la Baudroie {Lophius piscatorius)," Archiv.

Zool. Exper., 2 ser. t. ix. pp. 125-190, plan, vi.-viii., 1891.

96. Haller, B. — " Uber das Centralnervensystem, iusbesoudere iiber das Riickenmark von Orlhayo-

riscus mola," Morpholog. Jalirbuch, Bd. xvii. pp. 198-270, Taf. xiii.-xv., 1891.

97. Haller, B. — " Der Ursprung der Vagusgruppe bei den Teleostiern," in Festschrift fiir Gegen-

baur, Bd. iii. pp. 45-101, Taf. i.-iv., Leipzig, 1897.

98. Herrick, C. J. — "The Cranial Nerve Components of Teleosts," Anat. Auz., Bd. xiii. pp. 425-431,

1897.

99. Herkick, C. L. — "Additional Notes on the Teleost Brain," Anat. Anz., Jahr. vii. pp. 422-431,

1892.

100. Hoffmann, C. E. E. — ' Beitrage zu Anatomic uud Physiologic des Nervus vagus bei Fischen,'

pp. 1-34, Taf. i., Giessen, 1860.

loi. Hoffmann, C. K. — " Klassen und Orduungen der Amphibieu," in H. G. Bronn's 'Die Klassen

und Ordnungeu des Thier-rcichs.' Wirbelthierc, Bd. vi. Abth. ii. pp. 190-227, 367-377,

Taf. xv.-xvii., xxi.-xxii., xxix., Leipzig u. Heidelberg, 1873-78.

102. Hoffmann, C. K. — "Zur Ontogenie der Knochenfischc," Archiv f. mikroskop. Anat., Bd. xxiii.

pp. 45-108, Taf. iv.-vi., 1884.

103. HoussAY, F. — " Sur la Signification metamerique des organes lateraux chez les Vertebres, par

P. Mitrophauow, analyse et critique," Archiv. Zool. Exper., 2 ser. t. ix. Notes et Revue,

pp. iv.-viii., 1891.

Review of work by P. Mitrophanow (142).

104. HoussAY, F. — "Theorie vertebrale du Crane et Theorie metamerique de la Tete et du Corps,"

in " Notice sur les Travaux scientifiques de M. Frederic Houssay," pp. 25—46, Paris,

1894.

105. Hyrtl, J.- — " tJber den Seitencanal von Lota" Sitzungs. der Kais. Akad. der "Wissensch., Math.-

naturw. CI., Bd. liii. pp. 551-557, Taf. i., 1866.

See abstract, Ann. Mag. Nat. Hist., 3rd ser. vol. xviii. p. 264, 1866.

106. Jackson, W. H., & Clarke, W. B. — "The Brain and Cranial Nerves of Echinorhinus spinosus,

with notes on the other Viscera," Jour. Anat. & Phys., vol. x. pp. 75-107, pi. vii., 1876.

107. Jherin'g, H. von. — 'Das peripherische Ncrvensystem der Wirbelthierc, als Grundlage fiir die

Keuntniss der Regioncn-bildung der Wirbelsiiule,' pp. 1-238, Taf. i.-v., Leipzig, 1878.

108. JuLiN, C. — " Le Systeme nerveux grand sympathique de I'Ammocoetes {Petroinyzon planeri)"

Anat. Anz., Jahr. ii. pp. 192-201, 1887.

Revised and reprinted in 112.

109. Julin, C. — " De la Valcur morphologique du Nerf lateral du Petromyzon," Bull, de I'Acad. Roy.

des Sci. de Belgique, ser. iii. t. xiii. pp. 300-309, 1887.

Revised and reprinted in 112.

1 10. Julin, C. — " Les deux premieres Fentes branchiales des Poissons Cyclostomes, sont-elles homologues

respectivement il rEvetit et a la Fente hyobrauchiale des Selacieus?," Bull, de I'Acad. Roy. des

Sci. de Belgique, ser. iii. t. xiii. pp. 275-293, plan, i., 1887.

Preliminary to 112.

SECOND SERIES. — ZOOLOGY, VOL. VII. 29

212 MR. F. J. COLE ON THE STEUCTUEE AND MOEPHOLOGT OF •

111. JunN, C. — " Reclierches sur I'Auatomie de I'Ammocoetes. — I. Les deux premieres Fentes branchiales

des Poissons Cyclostomes, sont-elles homologues respectivemeut k I'^vent et a la Fente hyo-

branchiale des Selaciens?," Bull. Sci. du Nord de la France et d. 1. Belgique, t. xviii. ser. ii.

ann.x. pp. 265-295, plan, iv., 1887.

Fuller than preceding, but preliminary to ii2.

112. JuLiN, C. — " Recherches sur I'Appareil vasculaire et le Systeme nerveux peripherique de

rAmmocoetes (Petromyzon planeri) . Horaologie entre la premiere fente branchiale definitive de

cet animal et I'^vent des Selaciens — valeur morphologique du corps thyroide," Archives de

Biologic, t. vii. pp. 759-902, pi. xxi.-xxiii., 1887. See criticism by A. Dohrn, 62, and also

reply by Julin, Zool. Anz., Jahr. xi. pp. 567-568, 1888.

113. Kingsbury, B. F. — "The Lateral line System of Sense Organs in some American Amphibia, and

Comparison with the Dipnoans," Trans, of the Amer. Micros. Soc, vol. xvii. pp. 115-154,

pi. i.-v., 1895.

114. Kixr.sBURY, B. F. — "The Structure and Morphology of the Oblongata in Fishes," Jour. Comp.

Neurology, vol. vii. pp. 1-36, pi. i.-v., 1897.

115. Klaatsch, H. — " Ueber die Bedeutung der Hautsinnesorgane fiir die Ausschaltung der Sklero-

blasten aus dem Ektoderm," Verhand. d. Anat. Gesellsch. a. d. ix. Vers, in Basel, voni 17-20

April, 1895 (Anat. Anz. Ergaiizungshcft z. Bd. x.), pp. 122-134, 1895.

116. Lenhosskk, M. v. — 'Beitrage zur Histologic des Nervensystems und der Sinnesorgane,' pp. 1-190,

Taf. i.-iii., Wiesbaden, 1894.

117. Lenhosskk, M. v. — " Die Nervenendigungen in den Endknospen der Mundschleimhaut der Fische,"

Verhand. d. naturf. Gesellsch. in Basel, Bd. x. pp. 92-100, Taf. ii., 1895.

1x8. Leroux, — "Recherches sur le Systeme nerveux des Poissons," Revue Scientif. t. xliv. — ser. iii.

t. xviii. pp. 278-9, 1889.

Abstract. Not by author. No record o£ anything further published.

119. Leuret, F., & Gratiolet, P.— 'Anatomic comparee du Systeme nerveux considere dans ses

rapports avec ^Intelligence,' t. i.-ii. Atlas, plan, i.-xxxii., Paris, 1839-57.

120. Leydig, F. — "Ueber die Schleimkanale der Knochenfiscbe," Miiller's Archiv f. Anat., Phys. u.

wissen. Med., pp. 170-181, Taf. iv. figs. 1-3, Jahr. 1850.

121. Leydig, F. — " Ueber die Haut einiger Siisswasserfische," Zeits. f. wissen. Zool., Bd. iii. pp. 1-12,

Taf. 1. figs. 1 & 2, 1851.

122. Leydig, F. — "Zur Anatomie und Histologic der Chimcera monstrosa," Miiller's Arch. f. Anat.,

Phys. u. wissen. Med., pp. 241-271, Taf. x. Jahr. 1851.

123. Leydig, F. — ' Beitriige zur mikroskopischeu Anatomie und Entwicklungsgeschichte der Rochen

und Haie,' pp. 1-127, Tab. i.-iv., Leipzig, 1852.

124. Leydig, P. — ' Anatomisch-histologische Untersuchungen iiber Fische und Reptilien,' pp. 1-120,

Taf. i.-iv., Berlin, 1853.

125. Leydig, F. — ' Lehrbuch der Histologic des Meuschen und der Thiere,' pp. 1-551, Hamm, 1857.

126. Leydig, F. — " Ueber Orgaue eines sechsten Sinnes, zugleich als Beitrag zur Keuutuiss des feineren

Baues der Haut bei Amphibien und Reptilien," Verhand. der Kais, Leop.-Carol. dent. Akad.

der Natur., Bd. xxxiv. Abhand. v. pp. 1-108, Taf. i.-v., 1868.

127. Leydig, F. — "Neue Beitrage zur anatomischcu Kenntniss der Hautdecke und Hautsinnesorgane

der Fische," in " Festschrift zur Feicr des hundertjalirigen Bestehens der natur. Ges. in Halle,"

pp. 129-186, Taf. vii.-x., Halle, 1879.

128. Leydig, F. — "Intt^gument und Hautsinnesorgane der Knochenfiscbe," Zool. Jahr. Abth. f. Anat.

u. Ontog., Bd. viii. pp. 1-152, Taf. i.-vii., 1895.

129. LiKoux, P. DE Sede, DE. — " Recherches sur la Liguc laterale des Poissons osseux," in "Theses

presentees h. la Faculte des Sciences de Paris," pp. 1-114, pi. i.-iv., Paris, 1884.

See criticism, 'American Naturalist,' vol. xix. pp. 612-613, 1885.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 213

130. LocY, W. A. — " Contribution to the Structure and Development of the Vertebrate Head," Jour.

of Morphology, vol. xi. pp. 497-594, pi. xxvi.-xxx., 1895.

131. Malbranc, M. — "Von der Seitenlinie und ihren Sinnesorganeu bei Amphibien," Zeits. f. wisseu.

Zool., Bd. xxvi. pp. 24-86, Taf. i.-iv., 1876.

132. Marcusen, J. — " Die Familie der Mormyren. Eine anatomisch-zoologische Abhandlung," Mem. d.

I'Acad. Imp. d. Sci. d. St. Petersbourg, vii"" ser. t. vii. no. 4, pp. 1-162, tab. i.-iv., 1864.

133. Mayer, F. — "Das Centralnervensystem von Ammocwtes," Anat. Anz., Bd. xiii. pp. 649-657,

Taf. i., 1897.

134. Mayer, F. J. C. — " Ueber den Bau des Gehirns der Fisehein Beziehung auf eine darauf gegriindete

Eintheilung dieser Thierklasse," Verhand. der Kais. Leop. -Carol, deut. Akad. der Natur.,

Bd. XXX. Abhand. vi. pp. 1-40, Tab. i.-vii., 1864.

135. Mayser, p. — " Vergleichend anatomische Studien liber das Gehirn der Knochenfische mit

besonderer Beriicksichtigung der Cyprinoiden," Zeits. f. wissen. Zool., Bd. xxxvi. pp. 259-364,

Taf. xiv.-xxiii., 1882.

136. McMuRRiCH, J. P. — "The Osteology of Aminrus catus (L.), Gill," Proc. of the Canadian lustit.,

Toronto, n. s., vol. ii. pp. 270-310, pi. ii., 1883-84.

137. M'DoNNELL, R.— " On the System of the 'Lateral Line' in Fishes," Trans. Roy. Irish Acad., vol. xxiv.

pp. 161-187, pi. iv.-vii., 1860-71.

138. Merkel, F. — ' Uber die Endigimgen der sensiblen Nerven in der Haut der Wirbelthiere,'

pp. 1-214, Taf. i.-xv., Rostock, 1880.

See criticism by B. Solger (194).

139. Miklucho-Maclay, N. VON. — ' Beitrage zur vergleichenden Neurologic der Wirbelthiere. I. Das

Gehirn der Selachier. II. Das Mittelhirn der Ganoiden und Teleostier,' pp. 1-74, Taf. i.-vi.

u. i., Leipzig, 1870.

140. MiNOT, C. S. — ' Human Embryology,' New York & Loudon, 1897.

141. MiTROPHANow, P. — " Uber die erste Anlage des Gehororganes bei niederen Wirbelthieren," Biolog.

Central., Bd. x. pp. 190-191, 1890-1891.

142. MiTROPHANOw, P. — " Note sur la Signification metamerique des Nerfs craniens," Congres Internat.

dc Zool., Sess. II., Moscou, part i. pp. 104-111, 1892.

See criticism by Houssay (103).

143. MiTROPHANOW, P.- — " Etude embryogenique sur Ics Selaciens," Arch, de Zool. Exper. et Gen.,

ser. iii. t. i. pp. 161-220, pi. ix.-xiv., 1893.

144. Monro, A. * — 'The Structure and Physiology of Fishes explained, and compared with those of

Man and other Animals,' pp. 1-128, tab. i.-xliv., Edinburgh & London, 1785.

145. MiJLLER, H. — "Den nervosen FoUikel-Apparat der Zitterrochen und die sogenannten Schleim-

kaniile der Knorpel-Fische," Verhand. der Physik.-medicin. Ges. in Wiirzburg, Bd. ii. pp. 134-

149, 1852.

146. NuHN, A. — 'Lehrbuch der vergleichenden Anatomic,' pp. 527-570, 644-645, Heidelberg, 1878.

147. OsBORN, H. F. — "A Contribution to the Internal Structure of the Amphibian Brain," Jour, of

Morphology, vol. ii. pp. 51-96, pi. iv.-vi., 1889.

148. Owen. R. — ' Descriptive and Illustrated Catalogue of the Physiological Series of Comparative

Anatomy contained in the Museum of the Royal College of Surgeons in London,' vol. iii.

part i. 'Nervous System and Organs of Sense,' pp. 1-208, pi. xxx.-xlii., London, 1835.

149. Owen, R. — 'On the Anatomy of Vertebrates,' vol. i., 'Fishes & Reptiles,' London, 1866.

150. OwsiANNiKow, Ph. — "Uber das sympathische Nervensystem der Flussneunauge, nebst einigen

histologischen Notizen iiber andere Gewebe desselben Thieres," Bull, de I'Acad. Imper. des

Sci. de St. Petersbourg, t. xxviii. pp. 439-448, 1883.

' Monro sectmdus."

29^

214 ME. r. J. COLE ON THE STEUCTURE AND MOEPHOLOGY OF

151. Parker, T. J.^ — 'A Course of Instruction in Zootomy (Vertebrata)/ pp. 86-129, London, 1884.

152. Parker, W. K. — "On the Structure and Development of the Skull in the Salmon [Sahnosalar, L.),"

Bakerian Lecture, Phil. Traus., vol. elxiii. pp. 9o-145, pi. i.-viii., 1873.

153. Parker, W. K., & Bettany, G. T.— ' The Morphology of the Skull,' pp. 332-336, London,

1877.

154. Parker, W. N. — "On the Anatomy and Physiology of Protopterus annectens,'" Trans. Roy. Irish

Acad., vol. XXX. pp. 109-230, pi. vii.-xvii., 1892.

155. Philpeaux, J. M., & VuLPiAN, A. — " Memoire sur la Structure de I'Encephale des Poissons

cartilagineux et sur I'Origine des Nerfs craniens chez ces Poissons, accompagn^ de Planches

explicatives," Comp. Rend. Acad, des Sci. Paris, t. xxxvii. pp. 341-344, 1853. See also for

report and discussion by Dumeril, Flourens, Duvernoy, Serres, and Prince Bonaparte, ibid.

t. xxxviii. pp. 336-345, 366-376, and 421-428, 1854.

156. Pinkus, F.— " Ueber einen noch nicht beschriebenen Hirnnerven des Protopterus annectens," Anat.

Anz., Bd. ix. pp. 562-566, 1894.

Preliminary to 157.

157. Pinkus, F. — " Die Hirnnerven des Protopterus annectens," Morpholog. Arbeiten hrsg. v. G. Schwalbe,

Bd. iv. pp. 275-346, Taf. xiii.-xix., 1894.

Abstract, Zool. Anz., Jabr. xviii., Litteratur, p. 40, 1895.

158. Platt, Julia B. — " Ontogenetic Difl'erentiatious of the Ectoderm in Necturus. Study IL On the

Development of the Peripheral Nervous System," Q. J. M. S., n. s., vol. xxxviii. pp. 485-547,

pi. xx.xvi.-x.xxviii., 1896.

159. Plessen, J. von, & Rabinovicz, J. — ■' Die Kopfnerven von Salamandra maculata im vorgeriickteu

Embryonalstadium/ pp. 1-22, Taf. i.-ii., Munich, 1891.

See criticism by Strong (204, p. 162 et seq.).

160. Pollard, H. B. — "On the Anatomy and Phylogcuetic Position of Polypterus," Zoolog. Jahrbiich.,

Abth. f. Anat. u. Ontog., Bd. v. pp. 387-428, Taf. xxvii.-xxx., 1892.

161. Pollard, H. B. — "The Lateral line System in Siluroids," Zoolog. Jahrbiich., Abth. f. Anat. u.

Ontog., Bd. v. pp. 525-550, Taf. xxxv.-xxxvi., 1892.

162. Pollard, H. B. — "The ' CirrhostomiaP Origin of the Head in Vertebrates," Anat. Anz., Bd. ix.

pp. 349-359, 1894.

Preliminary to 163.

163. Pollard, H. B. — "The Oral Cirri of Siluroids and the Origin of the Head in Vertebrates," Zool.

Jahr., Abth. f. Anat. u. Ontog., Bd. viii. pp. 379-424, Taf. xxiv.-xxv., 1895.

164. Rabl, K. — " Uber das Gebict des Nervus facialis," Anat. Anz., Jahr. ii. pp. 219-227, 1887.

165. Ransom, W. B., & Thompson, D'A. W. — " On the Spinal and Visceral Merves of Cyclostomata,"

Zool. Anz., Jahr. ix. pp. 421-426, 1886.

Sec criticism by Dohrn (62).

166. Rex, H. — " Bcitrage zur ^lorphologie der Hirnveneu der Elasmobranchier," Morpholog. Jahrbuch,

Bd. xvii. pp. 417-466, Taf. xxv.-xxvii., 1891.

167. Richard, J. — -"Sur les Fonctions de la Ligne laterale du Cyprin dore," Comp. Rend. Hebdom.

des Sean, et Mem. de la Soc. de Biol. ser. x. t. iii. pp. 131-133, 1896.

See criticism by P. Bonuier, " Sur le Sens lateral," ibid. pp. 917-919, 1896.

168. Roux, Le. — See Leroux (118).

169. RuuE, G. — " Ueber das peripherische Gebiet des Nervus facialis bei Wirbelthieren," in Festschrift

fiir Gegeubaur, Bd. iii. pp. 193-348, Leipzig, 1897.

170. Sagemehl, M. — " Beitrage zur vergleichendcn Anatomic der Fische. I. Das Cranium von Amia

calva, L.," Morphol. Jahrb., Bd. ix. pp. 177-228, Taf. x., 1883-84.

English translation by Shufeldt (q.v. — 187).

THE CEANIAL NERVES AND LATERAL SENSE ORGANS OF FISHES. 215

171. Sagemehl, M. — " Beitriige zur vergleichenden Anatomie der Fische. II. Einige Bemerkungen iiber

die Gehirnhaute der Knochenfische," ibid. pp. 457-474, Taf. xxiii., 1884.

172. Sagemehl, M. — " Beitriige zur vergleichenden Auatomie der Fische. III. Das Cranium der

Characinideii nebst allgemeinen Bemerkungen iiber die mit einem Weber'schen Apparat

versehenen Physostomenfamilien," ibid. Bd. x. pp. 1-119, Taf. i.-ii., 1884-1885.

173. Sagemehl, M. — " Beitrage zur vergleichenden Anatomie der Fische. IV. Das Cranium der

Cyprinoiden," ibid. Bd. xvii. pp. 489-595, Taf. xxviii.-sxix., 1891.

174. Sanders, A. — "Contributions to the Anatomy of the Central Nervous System iu Vertebrate

Animals. Part I. Ichthyopsida, Section I. Pisces, Subsection I. Teleostei," Phil. Trans, vol. clxix.

pp. 735-776, pi. Iviii.-lxv., 1879.

175. Sappey, p. C. — ' fitudes sur I'Appareil raucipare et sur le Systeme lymphatique des Poissons,'

pp. 1-64, pi. i.-xii., Paris, 1880.

176. Sarasin, P. & F. — "Einige Puncte aus der Entwicklungsgeschichte von Ichthyophis glutinosus

{Epicrium gl.)," Zool. Anz., Jahr. x. pp. 194-197, 1887.

Preliminary (in part) to 177.

177. Sarasin, P. & F. — "Zur Entwicklungsgeschichte und Anatomie der ceylonesischeu Blindwiihle

Ichthyophis glutinosus, L.," in ' Ergebnisse naturwissenschaftlicher Forschungeu auf Ceylon,'

Bd. ii. pp. 4.3-56, Taf. iv.-vii., Wiesbaden, 1887-1893.

178. Savi, p. — " Etudes anatomiques sur le Systeme nerveux et sur I'Organe electrique de la Torpille,"

in C. Matteucci's ' Traite des Phenomenes electro-physiologiques des Animaux,' pp. 272-348,

pi. i.-iii., Paris, 1844.

179. ScHENCK, F. — See Fuchs (78).

180. ScHEPiLOFF, Catherine. — " Recherches sur les Nerfs de la viii""' paire cranienne et sur les Fonctions

du Cerveau et de la Moelle chez les Grenouilles, avec un Aper9U comparatif des Fonctions du

Systeme nerveux central dan.s la Classe des Batraciens," Mem. de la Soc. de Phys. et d'Hist.

nat. de Geneve, t. xxxii. no. 6, pp. 1-115, plan, i., 1894-97.

181. Schulze, F. E. — " Ueber die Nervenendigung iu den sogenannten Schleimkanalen der Fische und

iiber entsprechende Orgaue der durch Kiemen atlimenden Amphibien," Arch. f. Anat., Physiol,

u. -wisscn. Medicin, pp. 759-7G9, Taf. xx., Jahr. 1861.

182. Schulze, F. E. — "Ueber die Sinnesorgane der Seitenliuie bei Fischen und Amphibien," Archiv f.

mikros. Anat., Bd. vi. pp. 62-88, Taf. iv.-vi., 1870.

183. Schwalbe, G.- — "Das Ganglion oculomotorii. Ein Beitrag zur vergleichenden Anatomie der

Kopfnerven," Jen. Zeits. f. Natur. h. v. d. Med.-natur. Ges. zu Jena, Bd. xiii. pp. 173-268,

Taf. xii.-xiv., 1879.

184. Sede, p. de. — See P. de Sede, de Lieoux (129).

185. Shore, T. W. — "The Morphology of the Vagus Nerve," Jour. Anat. & Phys., Norm. & Path.,

vol. xxii., u. s. vol. ii., pp. 372-390, 1888.

186. Shore, T. W. — "On the miuute Anatomy of the Vagus Nerve in Selachians, with remarks on the seg-

mental value of the Cranial Nerves," ibid. vol. xxiii., n. s. vol. iii., pp. 428-451, pi. xx.-xxi., 1889.

187. Shufeldt, R. W. — "The Osteology of Amia calva, including certain special references to the

skeleton of Teleosteans," from the 'Annual Report of the Commissioner of Fish and Fisheries

for 1883,' pp. 747-878, pi. i.-xiv., Washington, 1885.

Contains translation of Sagemehl's paper (170, q. v.).

188. Solger, B. — " Zur Kenntuiss der Seitenorgane der Knochenfische," Central, f. d. Medicin. Wissen.,

Jahr. XV. pp. 657-658, 1877.

189. SoLGERj B.- — " Zweite Mittcilung iiber Seitenorgane der Knochenfische," ibid. pp. 817-820, 1877.

190. SoLGER, B. — "Ueber die Seitenorgane der Fische," Leopoldina, Kais. Leop.-Car. deut. Akad. der

Natur., Dresden u. Halle, Hft. siv. pp. 74-80, 1878.

216 MR. F. J. COLE ON THE STEUCTUEE AND MORPHOLOGY OF

191. SoLGER, B. — " Neue Untersuchungen zur Anatomie der Scitenorpane der Fische. I. Die Seiten-

organe von Chimara," Arcliiv f. mikros. Auat., Bd. xvii. pp. 95-113, Taf. viii., 1880.

192. SoLGER, B.- — "Neue Uutersucbungen zur Auatoraie dcr Scitenorgane der Fische. II. Die Seiten-

organe der Selachier," ibid. pp. 458-479, Taf. xxxix., 1880.

193. SoLGER, B. — " Neue Untersuchungen zur Anatomie der Seitenorgane der Fische. III. Die Seiten-

organe der Knochenfischc," ibid. Bd. xviii. pp. 3G4-390, Taf. xvii., 1880.

194. SoLGER, B.— "Ueber den fcinercn Bau der Scitenorgane der Fische," Bericht ii. d. Sitzung. d.

naturf. Gcs. zu Halle, pp. 105-109, Jahr. 1880.

Criticism of F. Merkel's work (138).

195. SoLGER, B. — See E. Bouenstein (24).

196. Stahr, H. — "Zur Funktion der Seitenorgane. Eine Beobachtung an chinesischen Zierfischen,"

Biolog. Central., Bd. xvii. pp. 273-282, 1897.

See abstract. Jour. Roy. Micros. Soc., August 1897.

197. Stannius, H. — " Ueber die Knocben des Seitencanales dcr Fische," Froriep's 'Neue Notizen a. d.

Gcbicte der Natur- uud Ilcilkunde,' Bd. xxii. s. 97-100, 1842.

198. Stannius, H. — "Ueber das peripheriscbe Nervensystem des Dorsch, Gadus callarias," Midler's

Arcbiv f. Anat. u. Physiol., pp. 338-366, Jahr. 1842.

Revised and incorporated in 199.

199. Stannius, H. — ' Das peripheriscbe Nervensystem der Fische, anatomiseh und physiologisch uuter-

sucht,' pp. 1-156, Taf. i.-v., Rostock, 1849.

See criticism by F. Ley dig (123), pp. 117-119.

200. Stannius, II. — " Handbuch der Anatomie der VVirbeltbiere. Zweite Auflage," Fische u. Amphibien,

Berlin, 1854-56.

201. Stieda, L. — " Studien uber das eentrale Nervensystem der Knochenfische," Zeits. f. wissen. Zool.,

Bd. xviii. pp. 1-70, Taf. i.-ii., 1868.

202. Strong, O. S. — "The Structure and Homologies of tlie Cranial Nerves of the Amphibia as

determined by their Peripheral Distribution and Internal Origin," Zool. Anz., Jahr. xiii.

pp. 598-607, 1890.

Preliminary to 204.

203. Strong, O. S. — "The Structure and Homologies of the Cranial Nerves of the Amphibia as

determined by their Peripheral Distribution and Internal Origin," Part 2, Anat. Anz., Jahr. vii.

pp. 467-471, 1892.

Preliminary to 204.

204. Strong, O. S. — " The Cranial Nerves of Amphibia. A Contribution to the Morphology of the

Vertebrate Nervous System," Jour, of Morphology, vol. x. pp. 101-230, pi. vii.-xii., 1895.

105. Swan, J. — ' Illustrations of the Comparative Anatomy of the Nervous System,' Second edition,

pp. 1-250, pi. i.-xxxv., Loudon, 1864*.

206. Thane, G. D. — "The Nerves" in ' Quain's Elements of Anatomy,' vol. iii. part ii., 10th ed.,

London, 1895.

207. Traquair, R. H. — " On the Asymmetiy of the Pleuroneetidse, as elucidated by an Examination of

the Skeleton in the Turbot, Halibut, and Plaice," Trans. Linn. Soc. London, vol. xxv. pp. 263-

296, pi. xxix.-xxxii., 1865.

208. Traquair, R. H. — ' The Ganoid Fishes of the British Carboniferous Formations. Part I.

Palseoniscidse,' printed for the Palseontographical Society, pp. 1-60, pi. i.-vii., London, 1877.

209. Traquair, R. H. — " On the Structure and Classification of the Asterolepidte," Proe. Roy. Phys.

Soc. Edinburgh, vol. x. pp. 23-46, pi. i.-ii., 1889.

* First published 1835.

THE CEANIAL NERVES AND LATERAL SENSE ORGANS -OF FISHES. 217

210. Tr AQV AiK, n. U.—" Homosteus, Asmuss, compared with Coccosteus, Agassiz/' ibid. pp. 47-57,

pi. iii., 1889.

211. Traquair, R. H.— " On the Structure of Coccosteus decipiens, Agassiz," ibid. pp. 211-324, pi. xi.,

1890.

212. Tkaquair, R. H.— "On Phlijctcenius [ = Phli/ctainaspis], a new genus of Coccosteidie," Geol. Mag.,

decade iii. vol. vii. pp. 55-61, pi. iii., 1890. See also Ann. & Mag. Nat. Hist., ser. vi. vol. xiv.

pp. 369-370, 189i.

213. Vetter, B. — " Untersuchungen zur vergleichenden Anatomic die Kiemen- uud Kicfermusculatur

der Fische." Theil I., Jcu. Zeits. f. Natur. h. v. d. Med.-natur. Ges. zu Jena, Bd. viii. pp. 405-

458, Taf. xiv.-xv., 1874.

214. Vetter, B.—Ibid. Theil II., ibid. Bd. xii. pp. 431-550, Taf. xii.-xiv., 1878.

215. VoGT, C, & Yung, E.— "Traite d' Anatomic comparee pratique," t. ii. pp. 339-552, Paris, 1894.

216. Weber, E. H.— 'Dc Aure et Auditu Hominis et Auimalium. Pars I. De Aurc Animalium

Aquatilium,' pp. 1-134, Taf. i.-x., Lipsiae, 1820.

2 17. Weber, E. H. — " Ueber vier Liingeniierven bei einigeu Fischen, von denen zwei von dem Trigeminus

und zwei von Vagus entspringeu, die die ganze Lange des Rumpfes durchlaufen," Meckel's

Arch. f. Anat. u. Physiol., pp. 303-308, Taf. iv. fig. 25, Jahr. 1827.

218. Westling, Charlotte. — " Beitrage zur Kenntniss des peripherischcn Nervensystems," Bihaug

till Kongl. Svenska Veteas.-Akad. Handliugar, Bd. ix. Hft. ii. Inn. viii. pp. 1-48, Taf. i.-iii.

1884.

219. Whitman, C. O. — " The Segmental Sense organs of the Leech," The American Naturalist, vol. xviii.

pp. 1104-1109, pi. xxxiii., 1884.

220. Whitman, C. O. — " Some new Facts about the Hirudinea," Jour, of Morphology, vol. ii. pp. 586-

599, 1889.

221. WiEDERSHEiM, R. — ' Elcmeuts of the Comparative Anatomy of Vertebrates,' adapted from the

German by W. N. Parker, pp. 1-488, London, 1897.

222. WiJHE, J. W. van. — " Ueber das Visceralskelett und die Nervea des Kopfes der Ganoiden und vou

Ceratodus," Niederland. Archiv f. Zool., Bd. v. pp. 207-320, Taf. xv.-xvi., 1879-82.

223. WiLLEY, A. — ' Amphioxus and the Ancestry of the Vertebrates,' pp. 21 & 42-45, New York &

London, 1894.

224. Willis, T. — 'Cerebri Anatomc : cui accessit Nervorum Descriptio et Usus,' pp. 1-456, Tab. i.-xiii.,

London, 1664.

Reprinted in ' Opera omnia Thomie Willis,' 1682.

225. Wilson, H. V.—" The Embryology of the Sea Bass {Serranus atrarlus)," Bull, of the United

States Fish Comm., vol. ix. pp. 209-277, pi. Ixxxviii.-cvii., 1889-91.

226. Wilson, H. V., & Mattocks, J. E. — "The Lateral Sensory Anlage in the Salmon," Anat. Anz.,

Bd. xiii. pp. 658-660, 1897.

227. Wright, R. R. — "On the Skin and Cutaneous Sense Organs of Amiurus," Proc. Canadian Inst.,

Toronto, n. s., vol. ii. pp. 251-269, pi. i., 1884.

228. Wright, R. R. — " On the Nervous System and Sense Organs of Amiurus," ibid. pp. 352-386,

pi. iv.-vi., 1884.

229. Wright, R. R. — " On the Hyomandibular Clefts and Pseudobranchs of Lepidosteus and Amia,"

Jour. Anat. & Phys., Norm. & Path., vol. xix. pp. 476-499, pi. xxiv., 1885.

2] 8 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

EXPLANATION OF THE PLATES.

The figures illustrating this paper have been carefully drawn, exact size, from nature, and, it is

hoped, are something more than mere diagrams. The various structures and bones figured will be

found to occupy their natural positions — every care having been taken to ensure this.

Plate 21.

Fig. ] . Dissection from the left side of Gadus morrhua, showing pit organs, sensory canals, and the

skeletal support of the latter. Natural size.

A. Articular.

Ao. Angular.

D. Dentary.

D.F. Anterior extremity of dorsal fin.

Fr. Frontal.

Fr^. Triangular fossa on frontal lodging the bend of the infra-orbital canal.

H. Hyomandibular canal.

7.0. Infra-orbital canal.

U. Supra-temporal portion of lateralis canal. ") , ,.

^ [- = Lateralis canal.

L^. Lateral portion of lateralis canal. )

Lg.H. Ligamentous portion of hyomandibular canal.

La.S. Ligamentous portion of supra-orbital canal.

L.O. First lateral line ossicle.

N. Anterior and posterior narial openings abnormally fused together (the specimen was

normal in this respect on the right side).

Na. Nasal.

0. Opercular fold.

PcT.F. Pectoral fin.

P.F. Post-frontal or sphenotic t Foramen for otic branch of buccal nerve.

Plv.F. Pelvic fin.

P.O. Pit organs (= sensory follicles).

P. Op. Pre-operculum.

P.T. Post-temporal or supra-scapula.

P.T^. Upper or epiotic limb of same.

P.T^. Lower or parotic limb of same.

Sb.O^. First sub-orbital or lachrymal.

Sb.O^'^. Sub-orbitals 2 to 6 (5 and 6 = first and second " post-orbitals "),

S.O. Supra-orbital canal.

S.O.C. Supra-orbital commissure.

Sq. Squamosal or pterotic.

S.T^'*. Supra- temporals ( = extra- scapulae) 1 to 4.

The numbers denote the dermal tubules of the respective sensory canals.

THE CKAMAL NEKVES AND LATERAL SENSK ORGANS OF FISHES. 219

Plate 22.

Fig. 2. Dissection from the left side of Gadns virens, showing the innervation of tlie sensoiy canals.

The latter are coloured in segments, to indicate the positions of tlic skeletal supports. The

lateral line nerves are shaded. Natural size.

A. Articular portion of hyomaudibular canal.

B. Buccal lateral line nerve.

B'. Outer Imccal nerve.

B". Otic branch of same.

B\ Branch of outer buccal to pit organ.

£'. Inner buccal nerve.

B". Upper ramus of same.

5". Branches of upper ramus to pit organs of snout.

B^. Lower ramus of inner buccal.

B". Branch of above to pit organs below infra-orbital line.

Cb. Cerebellum.

C.H. Cerebral hemisphere.

Cn. Outline of cornea.

D. Dentary portion of hyomaiidibuhir canal.

D.F. Anterior extremity of dorsal fin.

Fx. Frontal portion of suiira-oi'bital canal.

Fj?'. Frontal portion of infra-orbital canal.

H. Hyomandibular nerve trunk.

H\ Anterior or larger division of same.

//^ Posterior or smaller division of same.

H^. Chorda tympani nerve (= prte-branchial or pra;-spiracular — facial).

H\ Hyoidean nerve {= internal mandibular, or post-branchial, or post-spiracular) .

H^. External mandibular lateral line nerve.

H^. Posterior branch of same to sense organs 11 and 12 of the hyomandibular canal.

H\ Anterior branch of same to facial and mandibular pit organs.

H.C. Hyomandibular sensory canal (violet).

I.e. Infra-orbital sensory canal (red).

L. Lateralis lateral line nerve.

L\ Supra-temporal branch of above.

L-. Posterior division of supra-temporal branch to sense organ 4 of the lateral canal, &c.

L^. Dorsal division of supra-temporal branch to sense organs 1 and 2 of the lateral canal, &c.

L'. Anterior division of supra-temporal branch to sense organ .'3 of the lateral canal, &c.

L''. Doisal ramus of lateralis nei've.

L^. Dorsal forward branch of same.

U. Ventral ramus of lateralis.

L.C\ Supra-temporal portion of lateralis canal. )

T /-.. T + 1 I 1-- 1 i- r 1 r = Lateralis sensory canal (brown).

L.t . Lateral portion or lateralis canal. j . J \ i-

L.G. Giinglion of superficial oplithahnic, buccal, and external mandibular lateral line nerves.

L.l. Lobus inferior.

L.O' ". Lateral line ossicles 1 to 3 supporting the lateralis canal.

Mb. Medulla oblongata.

Mif. Third or mandibular or inferior maxillary division of tlu^ trigeminus.

Mx. Second or maxillary or superior maxillary division of the trigeminus.

SECOND SERIES. — ZOOLOGY, VOL. VII. 30

220 ME. F. J. COLE ON THE STRUCTURE AND MORPHOLOGY OF

Mx.Mn. Maxillo-mandibulav trunk (trigeminus).

N. Autei'ior and posterior narial openings.

Na. Nasal portion of the supra-orbital canal.

0. Opercular fold.

O.L. Optic lobe.

Olf. " Olfactory lobe."

PcT.F. Pectoral fin.

P.F. Post-frontal or sphcnotic portion of the infra-orbital canal.

Pzr.F. Pelvic fin.

P.O. Pit organs or sensory follicles.

P.Op. Pre-opercular portion of the hyomandibular canal.

P.T. Post-temporal or supra-scapular portion of the lateralis canal.

Sb.O\ First sub-orbital or lachrymal portion of infra-orbital canal.

Ss.O-''. Posterior sub-orbital portions of infra-orbital canal.

S.C. Supra-orbital sensory canal (blue).

S.Cm. Commissure between the two supi'a-orbital sensory canals.

S.O. Superficial ophthalmic nerve trunk (= lateral line and trigeminal portions).

/S.O'. Superficial ophthalmic lateral line nerve.

S.O". Superficial ophthalmic or first division of the trigeminus.

S.O^. Branch of -S.O.' to sense organ 4 of the supra-orbital canal. The two twigs probably

supply pit organs.

S.OK Branch of S.O.' to pit organ (?).

S.Q\ Branch ol S.O.' to skin.

S.O^. Anterior termination of S.O.- which has become separated from the lateral line nerve.

Sq. Squamosal or pterotic portion of the infra-orbital canal.

S.T^~^. Supra-temporal or extra-scapular portions of the lateralis canal.

V. Vagus nerve with compound (?) ganglion.

1. Olfactory tract, peduncle, or "nerve."

II. Optic nerve.

V.-VII. Trigemino-facial ganglionic complex (adult condition), with portions of its two roots.

The numbers denote the sense organs and dermal tubules of the respective sensory canals.

Plate 23.

Fig. 3. Transverse section of the head of a young adult Gadas virens, passing through the eye posterior

to the lens, x 27. Drawn with camera.

1. Supra-orbital sensory canal.

2. External aperture of the 4th dermal (com-

missural) tubvile of supra-orbital canal.

3. Superficial ophthalmic lateral line nerve.

4. Branch of above [=8.0.' of Fig. 2) to sense

organ 4 of supra-orbital canal (note its

condition on the other side).

5. Ophthalmicus superficialis trigemini.

6. Infra-orbital sensory canal.

7. Upper and lower rami of inner buccal lateral

line nerve.

8. Superior maxillary Vth.

9. Inferior maxillary Vth.

10. Allis's nerve " c " (see text). Distributed to

tissues behind and below eye.

11. Hyomandibular sensory canal, showing sense

organ 8 of this line.

12. External mandibular lateral line nerve.

13. Mandibular pit organ.

14. Optic chiasma.

15. Posterior extremity of cerebral hemispheres

(no lateral ventricles).

1(5. Frontal bone.

THE CEANIAL NEEVES AND LATEEAL SENSE OEGANS OF FISHES.

221

17. Fifth sub-orbital.

18. Anterior extremity of pre-operculum.

19. 1 Primordial cranium. 20 = the " supra-orbital

20./ bands" of Parker (152, p. 129).

21. " Great fontanelle" (Parker, loc. cit.)

22. Fused trabeculse ( " inter-trabecula ") .

23. Parasphenoid.

24. Metapterygoid.

25. Syraplectic.

26. Quadrate.

27. Cerato-hyal.

28. Brancliiostegal rays.

29. Gill arches, with attached muscles, blood

vessels, and gills.

30. Fragments of thyroid gland.

31. Phaiyngeal chamber.

32. Anterior extremity of opercular chamber.

33. Retina.

34. Sclerotic.

35. Superior rectus -1

36. Inferior „ I eye muscles.

37. Internal „ J

Fig. 4. Transverse section of sense organ 3, supra-orbital canal, from a young Gadus virens. X 240.

Details filled in with Zeiss Apochr. Hom. Imm. 2'0 mm., apert. r30, oc. compens. 4,

45 mm.

1. Sensory cells of sense organ.

2. Glandular cells of same (note periphery of

organ consisting entirely of gland cells, 2',

and centrally the secretion of the latter

passing between the sensory cells).

3. Cupula terminalis (apparently contracted from

its original attachments).

4. Nerve of sense organ.

5. Supra-orbital canal in transverse section.

6. Blood vessels.

7. Lateral frontal [i. e. lateral line ossicle

secondarily fused on to frontal) .

8. Frontal.

Cole.

Trans Linn, Soc Zool. Ser SVol.VII, PI 21.

F J Cole dc!

K'Faj-Unc A. HrsViac LitV Ec;

NERVES AND LATERAL SENSE ORGANS OF FISRES

Cole

Trans Linn Soc- Zool. Ser 2 VolYII. PI 22.

ti-

GADUS VIRENS. nat. s

F J Cole, del

M'FarlaJie 4- Er:Kme. I.nJi''' Edir.'

NERVES AND LATERAL SENSE ORGANS OF FISHES

Cole.

Trans Linn Soc Zool, Ser 2 VolVII, P1.23.

V\i 4. < 240

Fi^. o. X 27

M'FiriaTie A.Erskir.c Luh'^' Ea.

NERVES AND LATERAL SENSE ORGANS OF FISHES.

LINNEAN SOCIETY OF LONDON.

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THE

AUG 29 ^aSS

TRANSACTIONS

OP

THE LINNEAN SOCIETY OE LONDON.

A CONTRIBUTIOX TOWARDS OUR KNOWLEDGE OF THE

MORPHOLOGY OF THE OWLS.

BY

W. P. PYCRAFT, A.L.S, M.B.O.U.

LONDON:

PRINTED FOK THE LINNEAN SOCIETY

BV TAVI.OR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY. W.

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

November 1898.

[ 223

VI. A Contribution towards our KnoiuJedge of the Morplioloqy of the Owls.

By W. P. Pycraft, A.L.S., 3LB.0.U.

(Plates 24-29.)

AUG '29 '■tjyt^ Head L'lst April, 1898.

Part I.— PTERYLOGUAPHY.

I. Introductory.

IHE foimdation of the j)i'esent paper was laid by Prof. Newton, when, at tlie close

of the year 1895, he sent me the remains — in the shape of a trunk — of a Sceloglnux

alhifacies which had but recently died, M'ith a request that I would try to " make

something of them," inasmuch as the bird "was exceedingly rare and verging on

extinction. This trunk was that of a bird which liad for some three years been in

the possession of Sir Fraccis Boileau, who had brought it to England from New

Zealand. Unfortunately it had been sent immediately after deatli to a taxidermist,

who had, however, been instructed to save the body for Mr. J. H. Gurney, from whom,

it came, through Prof. Newton, to the Department of Comparative Anatom.y of the

University Museum of Oxford, where I was then woi'king. Thus it happens that

certain points concerning the external anatomy are probably lost for ever. The general

pterylosis, and details of the form of the external aperture of the ear, ought to have been

carefully examined in comparison with that of other species ; but as it is, the only

information on the subject we possess we owe to Mr. J. H. Gurney (7) and the kindness

of Prof. Newton, who generously lent me a stuffed specimen and gave me permission to

relax the skin and make what I could of an examination of its pterylosis. This I liave

done, and the results will be found embodied in this paper.

It struck me that the best method of learning something about Sceloglaux was to be

attained by first of all gathering as much information as possible about all the other

Owls, as by this means we might hope to gain som.e insight as to its probable systematic

position.

The present paper represents the first fruits of an attempt to realize this end, and

deals with the external topography only. Later I propose to describe the Osteology,

Myology, Syrinx, Sacral Nervous System, and Visceral Anatomy of all the species

whose joterylosis is now described, and of as many additional species as can be

obtained.

The pterylosis of Asio accipitrimis has lieen taken as the type of the paper and is

described in some detail, wliile only the salient features of the remaining species have

been touched upon.

In this first part the pterylosis of some 20 species is described. I have been liberally

supported by fi'iends interested in the subject, and wish here to record my deej) sense

of indebtedness to those who have contributed material.

SECOND SERIES. — ZOOLOGY, VOL. VII. 31

224 ME. W. P. PYCEAPT ON THE

Ri'st of all my tlianks are due to Prof. Newton, who started tlie work, provided me

with a valuable collection of skeletons, and furnished me with an unlooked-for chance

of examining the pterylosis of Sceloglaux. Moreover, he has helped me throughout the

preparation of this essay by kindly sympathy and advice.

To Dr. Sclater and Mr Beddard I owe much ; they have furnished me with valuable

material from the Zoological Gardens, amongst which I would mention Bnho lacteus,

B. mrgiiiianus, B. tovqnatus, Speotyto, and the only Barn Owl I have been able to

examine.

Mr. Jesse, of La Martinifere College, Lucknow, sent me some beautifully preserved

embryos o^ Athene hrama and other material. Mr. Allan Wilson, of Wadham College,

Oxford, procured me the Tawny Owl from which the description which follows was taken,

and since then I have had one other from the Zoological Gardens.

Lastly I have to record the share contributed to this paper by one who has since

passed away. I allude to the death of one of my kindest and best of friends, Mr. Daniel

^leinertzhagen. His loss Avill be keenly felt, not only by those to whom he had endeared

himself in a thousand different ways, but by ornithologists at large. Young, enthusiastic,

an exquisite draughtsman, a most careful worker, and imbued with a deep love of

Ornithology, he seemed in every way one from whom we might expect great things,

and had he lived we should not have been disappointed. He took the keenest interest

in the progress of this work, and furnished me with most of the forms herein described

from liis aviaries at Mottisfont Abbey. Amongst the rarest are the Tengmalm's Owl,

Ural Owl, Snowy Owl, Ninox, Hawk Owl, and Scops. To his pen we owe the very

beautiful and accurate figures which form the Plates illustrating this part. These were

drawn in Prof. Lankester's Laboratories at Oxford, where we were both working, and

they represent the last work he ever did before taking his farewell of the University.

II. Historical.

Almost all that we know concerning the pterylography of the Owls we owe to Nitzsch

(13). Regarding them as closely allied to the Accipitres, he yet realized that they differed

pterylologically from them in many important particulars, svich as the absence of an

altershaft to the feathers, the absence of down-feathers on the pterylae, and the nude oil-

gland. In their general pterylosis, as he pointed out, they bear what is certainly a

striking resemblance to the Falcons ; but, as will be shown later, the points which he

selected as distinguishing the Owls from these break down when applied to a large

series of examples.

His study of the pterylography induced him to divide the Owls into two sections by

cutting off the Barn Owls as a gronp by themselves apart fi-om the rest. Later researches,

taking into account the osteology and myology of the two groups, have confirmed his

action.

According to Nitzsch the pterylosis of all the Owls, save Strix, was exactly the same

as in Bubo (Stria; bubo, 'L., = B. ignavus, Forst., was tlie type figured), save in one or two

minute points, the various species being distinguished one from another by the relative

MOKPHOLOGY OF THE OAVLS. 225

lengths of the primaries and the amount of the emargination of their inner vanes. In

Speolyto, save for the spinal tract, he tells us that " the pterylosis differs in no respect

from that described for S. bubo.'"

In the Barn Owls the ventral tract is said to " agree precisely with that of Cathartes,

only differiug in that, in Utjhris { = Slria; Jlammea), the contour- feathers are more

numerous aud stand closer together." He was the first to draw attention to " two

minute feathers seated at the apex of the oil-gland."

The Ibrin and nature of the facial disc are very carefully described, but he does not seem

to fully apj)reciate the difierenciis in the form of the external aperture of the ear and of

the opercular fold in the various Owls.

I have been unable to confirm his description of the disc-feathers of S. otiis { — Asio

otus). According to him, " they consist of a large tube perfectly open above, upon which

a very small, sparsely-barbed shait is seated."

As will be seen later, my own investigations bear out the main conclusions of Nitzsch's

work most completely. The wonder is that he failed to notice the numerous small but

very real ditiercnces by w^hich not only genera but even species may be distinguished.

It is also a matter for some surprise to find liim so closely associating Syrnium and Scops,

the pterylosis of which is said to be "as in Bubo.'' The resemblance between Bubo and

Scops is undoubtedly very great, as he indicates, but Sp'uium can be very readily

distinguished from either.

It is somewhat strange to find that Kaup (8), in his " Monograph of the Strigidse,"

published in the Trans. Zool. Soc. 1862, makes no mention of Nitzsch's work. He takes

into account only such facts as the presence or absence of '• horns," the form of the disc

— which he divides into a central " veil " surrounded by a " wreath," — the length of the

primary remiges, and whether or not they are eniarginate, and the presence or absence

of featiiers on the acrotarsium and acropodium. He draws attention to the fact that the

feathers seated in the posterior membranous fold surrounding the external aperture of

the ear are so arranged as to slope in opposite directions, meeting at an obtuse angle.

The feathers in the upper half of the fold are directed downwards, those in the lower

half are directed upwards. The feathers in this fold constitute the " wreath."

Besides these, he also employed such external features as the form of the nostrils, the

development of the " cere," and the size of the external aperture of the ear. The points

noticed in the latter were (1) the size, measured with relation to the long axis of the

eyelids, its symmetry or asymmetry, and (2) the presence or absence of an operculum

or " anterior ear-lap " and of a posterior or " hinder ear-lap." The somewhat com-

plicated relations which, obtain in the asymmetrical ear-apertm*es of Asio are fairly

well described.

The systematic arrangement resulting from his labours *, however, is decidedly inferior

to that of A'itzsch. He divided the Owls into two subfamilies, Syrniinse aud Striginse.

* The osteology of the skull also found a place in his diagnoses. He employed such characters as the form of tho

occipital region and the pncumaticity of the bones. He was, I believe, the first to point out the swollen spongy

nature of the interorbital septum of the Barn Owl.

31*

226 ME. W. P. PYCEAFT ON THE

The former contained tlie genera Olaucidium, Ntjctala, Athene, Syrnia, and leroglawx,

the latter Scops, Otus, Bnho, and Strix.

In the earlier editions of Yarrell's well-known ' History of British Birds,' the scheme

of classification which was followed for the Owls was that of dividing the group into

" horned " and " hornless." This jilan was discarded some six-and-twenty years ago hy

Prof. Newton when he undertook the task of re- writing this work (12). He adopted in

the main that of Messrs. Sclater and Salvin. Internal characters apart, they were

divided into two groups, the one, representing the Barn Owl and its allies, characterized

hy the disposition of the feathers of pt. ventralis, the form of the operculum, the

straightness of the heak at the hase, and a serrated middle claw. Tlie other was further

subdivided into " the Owls which possess an operculum to the ear and the Owls which do

not;" .... " to the first of these belong the Tawny, Tengmalm's, the Long-eared and

Short-eared Owls, and to the second the remainder of the species."

Whether the subdivision adopted for this latter group is destined to prove the right

one or not I will not venture to say ; for my own part I have some doubt as to its power

to hold its own. The form of the operculum and cavernum (p. 259) in Asio and

Syrnium have really very little in common, whilst that of Ni/ctala can hardly be called

an operculum at all.

The minor characters utilized in the formation of genera were such as the form of the

facial disc, length of the remiges, presence or absence of " ear "-tufts, feathering of

the legs, and the form of the external aperture of the ear, whetlier symmetrical or

not.

Pour years after the publication of Prof. Newton's work Dr. Sharpe brought out his

'Catalogue of the Striges ' (16). Measurements, and such points as the size of the

external apertures of the ear, measured with relation to the length of the horizontal axis

of the eyelid, the presence or absence of an operculum, and the development of the facial

disc, are the characters which he adopted for the purpose of breaking up the group into

genera and species.

Pollowing Sclater and Salvin, he divided the Owls into two groups — the Striyidce,

containing the Barn Owl and its allies, and the JBubonidce. The only external characters

adopted for the purposes of this di\dsion were the relative lengths of the middles

toe and the presence or absence of a serration along the inner margin of the claw of

that digit.

The Buhmiidce were further subdivided into the Buhoiiina;, with the " ear-couch not

larger than the eye (? eyelid), without an operculum; facial disc unequal, the portion

below the eye being always much greater than the area above the latter ;" and the

Syrniince, with the " ear-conch much larger than the eye, with very large operculum

shutting in the ear ; facial disc always distinct, and extending as far above the eye as

below it." These two sub-families agree with Prof. Newton's — those which possess an

operculum to the ear, and those which do not. In addition, however, to the question of

the presence or absence of an operculum, Sharpe takes into account the size of the

aperture of the ear ; this w as a step in the right direction, but it was not enough, since

even now Owls are brought together which ought to be placed in separate sub-families.

i

MOEPHOLORY OF THE OWLS. 227

Thus, Stjrnia, Carine, Speotyto * are placed in the Bubonlnce, to wliich I do not think

they rightly belong, whilst Aslo, Sijniium, and Nyckda probably represent as many

sub-families.

Dr. Gadow (2-4) accepts Nitzsch's diagnoses of the general pterylography of the Owls.

In one point, however, he is confident where Nitzsch wavered, inasmuch as he states

that down-fpathers occur and are confined to the apteria. Nitzsch was doubtful on this

point, but observed that he had never fou]id them when he searched for them. As a

matter of fact, they occur only in ih.o, pt. ularis (PL 24, d.f.).

In the structure of the neossoptiles Gadow considers the Owls to approach the Goat-

suckers. He remarks that they are double as long as the neossoptiles of the Accipitres,

and are further cliaracterized by their extreme softness (" weichlieit "). As will be pointed

out later (p. 253), the " nestling-down " of the Accipitres is of two kinds — one pi-eceding

the future definitive contour-feather, and one preceding tlie future definitive down-feather ;

and it is probably with this last that the " nestling-down " featlier of the Owl has been

compared, instead of with the former, with \^■llich it really corresponds.

Moulting takes place once annually, in July and August.

Although the curious separation of the external aperture of the asymmetrical ears of

Aslo into two chambers (p. 259) is briefly described, no mention is made of the " oper-

culum " or of the posterior membranous fold fencing in this aj^jcrture from behind.

Meijere, in his papers on the distribution of the hair in the Mammalia (9) and of the

feathers amongst Birds (10), has brought to light some most interesting and valuable

facts. In his first paper he sets himself the task of proving that there is considerable

evidence to show that the arrangement of the Mammalian hair indicates the presence of

an earlier clothing of scales f . On the loss of the scales the hairs remain, and thus is

explained their peculiar distribution in groups of three or more, as the case may be.

The author, in bis second paper (10), points out the close similarity in the arrange-

ment between hairs and feathers, and remarks that, though he does not wish to imply an

homology between these structures, yet their close resemblance in this particular would

be a not unimportant argviment in favour of such homology if it were supported by other

evidence. But our knowledge on this point is as yet very meagre.

According to Meijere, at a certain stage in the development of the Avian type the

liody-clothing consisted of alternating groups of similar feathers, whose long shaft bore a

biserial system of branches — Rami. These, in their turn, supported a biserial system of

smaller branches — Radii. The latter consisted of a row of cells, provided distally with

a pair of fila (" wimperchen"), which probably here and there took the form of booklets.

Later, the middle feather of each group developed at the expense of the rest, which now

assumed the form of the diminutive feathers which we know as Filoplumes. The middle

* I am only takiug into account such genera as I have had the opportunity of studying ; Hetero'jlaux and Gi/ninasio

have not yet come under my ken.

t The nature of the combined covering of scales and hairs can bo studied on the scaly tails of such animals as

Mas decumanus. Here they arise in groups of three from behind each scale, the middle one being the strongest. In

some cases the number of hairs associated with each scale is greater than three. In Castor fiber, for instance, there

are eight such hairs. In cases of this kind the hairs seem aU to be of equal calibre.

228 ME. W. P. PrCEAFT ON THE

feather became either a true contour-feather, in which the Fila became more and more

perfectly specialized to form " Hooklets," at the same time as the shaft, rami, and radii

increased in strength, or it became a true down-feather. In the latter case the change

might be brought about in two ways : — (1) the radii became relatively weaker and more

numerous, and the fila of the radii became metamorphosed in various ways, or (2) the

shaft became very considerably shorter and weaker. Umbelliform (" doldenformige ")

dowu-feathers represent reduced long-shafted feathers. The same, he thinks, may be said

of umbelliform neossoptiles. As to whicli is the older of these two primitive types of

long-shafted feathers we know at this time nothing for certain.

In the course of his paper on the distrihution of feathers Meijere briefly discusses the

arrangement of the feathers covering the tarso-metatarsus of a young Barn Owl. These

he describes as seated in groups of three, a median and two lateral, under the anterior

margin of the scales of the podotheca. Such an arrangement recalls, he reminds us,

that which obtained on the scaly tail of Mns decumanus. The median feather was much

the largest ; the two lateral repi*esented degenerate contour-featiiers sunk to the level of

filoplumes. On the tibio-tarsus the feathers are also described as arising in groups of

three, but the median feather is here mucli more developed, possessing a distinct though

seraiplumous vane. In an adult Barn Owl the lateral feathers of the scales of the podo-

theca were wanting or occurred sparingly. Down-feathers and degenerate filoplumes are

described as occurring on the dorsal apterium. On the breast filoplumes are stated to

occur sjjaringly.

I find myself vmable to confirm one or two small points in this paper, inasmuch as

after careful search I failed to find more than a single filoplumu to each feather on the

tibio-tarsus, nor could I succeed in finding any filoplumes associated with the down-

feathers of the Owls examined by me.

As touching matters of identification, it seems to me that Meijere has failed to distin-

guish between true down-feathers and semiplumes. The latter occupy the position of

and represent contour- feathers which are in process of degeneration and final disappear-

ance— the modus ojjerandi of the formation of pterylJB. Down-feathers occupy the spaces

between contour-feathers. This makes it rather difficult to accept the hypothesis that

thev are degenerate contour-feathers.

III. Pteroltsis of the Adult.

Asio ACCIPITRINUS, Pall. (PI. 25. figs. 1-3.)

PterylcB : —

Fteryla capitis. — For the purposes of convenience in description this tract will be

described throughout under the following subdivisions : —

Fronto-parietal are a. — This extends from the base of the beak to the crown of

the head. It is clothed by a narrow median band of feathers, expanding later to cover

the occipital area. On either side of this median band, in the region corresponding

with the level of the superior limb of the crescentic membranous folds surrounding the

MORPHOLOGY OF THE OWLS. 229

external aperture of the ear, lies a single longitudinal row of some 6-7 feathers distinctly

longer than those in the neighbourhood, whose shafts are directed outwards and back-

Avards; they form the " ear "-tufts or " horns." Running along the outside of the bases

of these '• ear "-tufts is an oblong apterium.

Occipital are a. — This is a backward continuation of the parietal area, terminating

at the occiput. Tlie feathers radiate from the middle line outwards and somewhat

upwards. As they approach the free edges of the post-aural ibid they gradually decrease

in size, and become at the same time more thickly planted.

Loreal area (PI. 25. fig. 2). — This is occujned by a somewliat cresceutie and

densely-packed group of stiff-shafted feathers (p. 25G). Its upper limb runs backwards

to terminate in the region above the middle of the eye. The lower limb runs downwards

and backwards behind the gape to join the feathers of the operculum.

Ocular are a. — In consequence of the fact that the eyes, instead of being sunk

entirely within the orbit, are directed outwards and forwards, a considerable portion of

the sclerotic ring is brought into close relation with the outer world. This portion is

protected by the eyelid, which is on this account of greater relative size than in other

birds. It is clothed by a more or less regular series of semicircular rows of feathers,

decreasing in size as they approach its free edge.

Circum aural area. — As its name implies, this area concerns the region around

the external aperture of the ear. In the present species, and in some o^her Owls, this

region is characterized by the considerable development of membranous folds of skin —

the pre- and postaural folds. When the former is largely developed, it is known as the

" operculum."

Operculum. — The feathers seated along tlie free edge of the operculum (PL 25.

fig. 2) are aU elongated, with narrow vanes ; they form a series of from 3 to 4 rows

liaving an outward and upward direction. Hunning parallel with the feathers on the

free edge, but separated by a considerable apterium, is a single row of feathers, differing

only from those of the free edge in that they are of a more slender character.

Postaural fold. — The feathers seated along the free edge of this fold form the

periphery of the disc (PI. 25. fig. 2). They belong respectively to the fronto-parietal,

occipital, and ramal areas, and are continvied downwards and forwards to unite in the

middle line near the syrapliysis of the mandil^le. They are compai-atively short, slender,

and nai'row-vaned, so densely packed that their embedded bases form a thickened rim to

the fold. The feathers occupying the lower segment of this " rim " are directed upwards,

and those in the lower segment downwards ; as a consequence, where the two series meet a

notch is formed (PI. 27. fig. 3). This point was apparently first noticed by Kaup (p. 225).

Ramal area (PL 25. fig. 2). — This may be divided into two sections — an anterior,

extending from the gape on each side of the ramus to the junction of the pre- and post

aural folds, and a posterior strongly-marked triangular section, the base of which merges

with the feathers of the postaural fold.

Inter ramal are a. — The space from the symphysis of the mandible Ijackwards to

the point where the inferior limb of the crescentic peripheral disc-feathers converges is

occupied by a broad truncated-conical patch of elongated, slender, forwardly-directed

230 ME. W. p. PYCEAFT ON THE

feathers. It is bounded on either side and in front by an aptevium. The remainder of

the interramal area lies behind the convergent ends of the peripheral disc-feathers, but

is almost directly lost in the pteryla colli ventralis (PL 25. fig. 2). It forms a narrow

tract of some two feathers in width. In one case, however, this expanded to merge on

either side with the mandibular area.

The facial disc is formed by the feathers of the opercular and loreal areas afl.d those of

the postaural fold. These last form the periphery of the disc.

Ft. colli dorsalis (PL 25. fig- 3). — A densely -feathered tract, not closely investing

the neck, but seated upon extensive lateral folds of skin, forming the T-shaped expansion

of a vertical median membrane. The tract is widest a little below its origin at the

occiput, then suddenly contracting, so that, at the point where it emerges with the

pf. s])in(ilis, it is reduced to an obliquely-transverse row of some 5 feathers. A membra-

nous fold investing a retractor muscle runs from the underside of the lateral neck-

membrane at a point a little below its greatest width, in an obliquely-downward direction,

to the pt. colli ventralis, and thence to the shoulder (PL 25. fig. 2).

Ft. spinalis (PL 25. fig. 1}. — It is not pos.sible to draw a hard-and-fast line separating

this at its upper end from the i^t- colli dorsalis. It is divided into aa upper A-sliaped

and a lower Y-shaped portion. The former will henceforth be called the interscapular

fork, and the latter the lumbar fork. The arms of the interscapular fork arise in the

upper third of the interscapular region — iu one sj)eciinen at the root of the neck, where

it took origin from the pt. colli dorsalis, there being no stem — and terminate on a level

with the free end of the scapula. The feathers are seated in obliquely-transverse rows of

not more than 4 feathers in each row. The branches of the lumbar fork are wide apart

and continued upwards on to that portion of the axillary membrane lying between the

humeral tract and the arms of the interscapular fork. A double row of semiplumous

feathers enters into the formation of each branch, and these converge into the common

stem some distance in front of a line drawn through the acetabular region. The stem is

made up of transverse rows of feathers arranged in triplets (thus — . * .). It is bifurcated

posteriorly, terminating just in front of the oil-gland, after somewhat increasiug in

width.

Pt. caudcv. — There are 12 rectrices.

Ft. colli ventralis. — This comes into existence in the form of a backward coutinuation

of the interramal tract. At first made up of a treble (transverse) row of feathers, it

gradually increases in width to the middle of the neck, where it forks, each branch rimning

to join the pt. ventralis at the shoulder.

Ft. ventralis (PL 25. fig- 3). — Three branches mu.st be recognized in this tract — an

outer, a median, and an inner. The outer is very distinct and runs backwards from the

shoulder across the pectoral muscles to the preaxial border of the patagium. The median

and widest of the three arises at the shoulder and runs backwards to within a short

distance of the level of the posterior border of the sternum ; here it turns abruptly

upwards and forwards to join the hypopteron. This upw^ard limb is the "hook" of

Nitzsch. The area between the hook aud its main stem is more or less thickly

MORPHOLOGY OF THE OWLS. 231

besprinkled with feathers. Tlie inner branch arises from the inner border of the median

at a point rather in front of the level of the anterior end of the carina stcrni, and runs

backwards and inwards to join its fellow of the opposite side in front of the cloacal

aperture. It is widest on the breast, and contracts suddenly on the abdomen, to form a

narrow band at some distance from the middle line. Its anterior end is ()l)li([uely trun-

cated ; the lower and outer angle receives the feathers forming the preaxial border of the

pt. marginalis ;. the vipper and inner angle is formed l)y a single row of feathers of the

pt. veutralis at the shoulder.

Fi. femoralis (PI. 25. fig. 2). — The limits of this tract are not sharply dehued. It is

continued forwards to form a pt. Imnhalis. Along the posterior border of the thigh there

runs a strongly-marked band of stout feathers, which is continued forwards to terminate

below the knee-joint. This band I shall call {hafemoro-cruralh^xiix.

Ft. cruralis (PI. 25. fig. 2). — The feathers of this tract are slender and do not invest

the leg completely, but leave the inner surface bare. This tract is continued downwards

over the acrotarsium and acropodium, to terminate over the penultimate phalanx of

each digit. The planta is bare.

Pt. alar is (PL 24) :—

Metacarpo-digitals (primaries) 11; 9th longest (reckoning from within

outwards) ; outer vane of the 10th serrated, with the tip of the inner vane emarginate ;

distal end of the 9th with the outer vane serrated; 11th reduced to the condition of a

remicle. Cubitals (secondaries) 14, the innermost small, not easily distinguished from

their major coverts. The wing is aquintocubital.

Tectrices : —

T. major es. — The major coverts of the dorsal surface of the manus large; the lltli

much longer than its remex (the remicle), but least of all the coverts of the hand

belonging to this row. Carpal covert and remex large, closely attached by their

base one to another and to the base of the 1st metacarpo-digital. The covert is larger

than the remex.

The dorsal major coverts of the cubital remiges are of imiform length throughout ;

sometimes, however, there is a distinct break in the continuity of the line formed by the

distal ends of these coverts. In such cases the break is found to be due to the fact that

the coverts 1-5 are slightly longer than the rest of the row, whilst no. G is slightly

shorter *. The row terminates at the elbow-joint, and is not carried inwards on to the

humerus. The overlap is distal.

On the ventral surface the feathers of the manus, with those of the cubital remiges,

gradually increase in length from without inwards. Overlap distal.

T. medicc. — On the dorsal surface of the manus this row commences at the 3rd meta-

* As will be shown later, in the Owls the cubital major coverts of the dorsal surface are usually of uniform length

throughout, locquality in the length of the major coverts is never found except in aquintocubital wings. The 5th

major covert is distinctly longer than the 6th in Lc[itoiitilus javanicns, Griis (ntstraliensis, (J. ciiurea, Ardea ciiicrea,

Palamcdea cornuta, Ccryle torquata, and Conurus.

The 5th major covert is shorter than cither the 4th or (ith in Megapodius n'uvliariensis.

SECOND SERIES. — ZOOLOGY, VOL. VII. 32

232 MR. W. P. PYCRAFT ON THE

carpal rem ex. The overlap is distal. On the forearm the coverts 1-5 are very consider-

ably the longest in the row, gradually increasing in length from without inwards. The

series terminates at the elbow and is not continued inwards on to the arm. The overlap

is proximal.

On the ventral surface of the manus this row terminates at the base of the 6th remex.

The feathers of the cubital series are fairly long and uniform in length, but concealed by

the 1st row of the t. minores, which are slightly longer and closely approximated at their

bases.

T. minores. — On the dorsal surface these coverts are wanting on the manus. There

are about 3 cubital rows, all with a proximal overlap. With the 1st row, as with the

median series, coverts 1-5 are considerably the longest in the row. The same is true of

the two succeeding rows, preaxially, but in the case of each row the differences of length

decrease rapidly.

On the ventral surface of the manus they are moderately long, replacing the t. medice

after the 6th metacarpal remex. Those of the cubital remiges are slightly longer, and

therefore conceal the t. medice. The 2ad row is made up of much smaller feathers than

the 1st. It is only represented on the manus by 3 feathers lying at the bases of the

metacarpal remiges 1-3. The 3rd row is not repi'esented on the manus. On the forearm

it follows the course of tlic ulna. In texture the feathers of this row are small and

semiplumous. The patagial membrane is clothed with 2 rows of degenerate semi-

plumous contour-feathers.

T. marginales. — On the dorsal surface there are 2 rows running along the preaxial

border of the manus. The greater part of the surface of the patagium is clothed by some

4-5 rows, which arc continued inwards along its margin as a closely-set triple row of

feathers, which ultimately join the ^9^. humeralis.

On the ventral surface there are from 2 to 3 rows. The coverts of this scries are seated

in closely-packed obliquely transverse rows. The postaxial row, seated on the patagium,

are very long, and overlap the semiplumous t. minores.

Parapteron. — This is made up of some 8 obliquely-transverse rows of 3 feathers in

each row. Of these, the middle feather is the longest. The most preaxial feathers at

the distal end of the arm rest on the humerus, the remainder on the muscles of the arm.

Viewed as a whole, the parapteron is of a rounded conical form. It is connected by a

double row of small feathers with the tectrices on the forearm. Whether these feathers

can be brought into serial relation with the tectrices majores and medics of the forearm

is a point not easy to determine.

Hypopteron. — Elongated, delicate, semiplumous feathers, running along the under

surface of the arm in some 6 transverse rows of 3 feathers in each row, make up the

BJijpopteron. Proximally they merge with the recurved end of the median branch of the

■pt. vcntralis.

Ala spuria. — Four strong feathers take part in the formation of the ala spuria.

It is a point worthy of remark that the feathers of the dorsal surface of the pt. alaris,

instead of being set in quincunx, form obliquely-transverse rows sloping from without

MOEPHOLOGT OF THE OWLS. 23-5

nwards. The only other birds that I can recall in wliicli a similar arrangement obtains

are Caprhmilgtis and Rhea.

Semiplumoi : —

Somiplumes * occur in the interscapular fork of the pt. spinalis, and compose tlu;

branches of the lower Y-shaped portion of this tract. The femoral tract is largely made

up of semiplumes. The inner border of the pf. humeralis is bounded by semiplumes, so also

is i\io.iit. colli ventralls ; they also cover the axillary patagial fold. If the wing of a frcsbly-

killed Owl be raised, a large bare sj)ace will be seen entirely liounded by semiplumes.

They run along the recurved limb of the median branch of ventral tract, downwards, or,

rather, backwards, from the origin of this to the pt. femoralls, the anterior border of

which forms its jiosterior boundary, and hem in the space dorsally through the branches

of the luml)£ir fork of the pt. spinalis, finally joining the j)Osterior end of the pt. humeralis.

Thus, this portion of the apt. trimc. laterale (p. 231<) is entirely shut off from that

lying between the pt. humeralis and pt. spinalis, and that between the inner and

median branches of the pt. ventralls and the inner branch of the pit. ventralis and the

thigh.

PlumulcB : —

Plumulaj or down-feathers are entirely absent on the trunk ; they occur onli/ on the

wing, and are distributed as follows : — On the dorsal surface they are absent along the

preaxial border of the wing ; behind this they occur singly between the contour-feathers

m such a way as to form a quincunx with them (thus — ' • )' ^'^^ down-featlier occupying

the centre. Two are found at the l>ase of every major covert, and two at the base of

every remex (PI. 27). On the manus there is but one doAvn-feather to each major covert.

Their distribution on the under surface of the wing is much as on the upper.

Filoplumce : —

The filoplumes are very slender and not easy to find. One or more occur at the base

of every contour-feather on the body.

Rhamphothcca. — The reniform external nares pierced through the anterior margin of

a soft slightly tumid membrane at the base of the beak, resembling the cere of the

Accipitres. For convenience' sake this will in future be called the cere.

Podolheca. — Clothed with feathers save the base of the terminal phalanx, which is

covered by 3 scales.

Claivs. — There are no claws on the wing ; those of the foot not much curved, rounded,

the inner border of the middle claw forming a sharp edge, decreasing in size from the

base downwards.

JJropygiwnt napiform. It is not tufted.

Moulting. — Moulting takes place once a yeai', in July and August. {Gadow.)

* It must be remembered that Semiplumoc are nothing more than degenerate coutour-feathers, and can always be

distinguished from down-feathers in consequence of their position on the body, which is, necessarily, serial with

the contour-feathers. Down-feathers arc always placed between contour-feathers when they occur on pterylic.

Semiplumes always occur along the margins of pteryla) — if the whole pteryla is not made up of semiplumes — aud

indicate a further restriction of a once wider tract.

32*

234 MK. W. p. PYCEAFT ON THE

Apteria : —

Ajjferinm cajnih.— The apteria of the liead are represented by the bare spaces

surrouudiug the eyelids, the spaces on the operculum, and the space on the outer side of

the feathers forming the " ear "-tufts (PL 25).

JpL colli laterale (PI. 25. fig. 2). — Extends from the base of the neck, as a continua-

tion of the apt. trntici lat., forwards to the base of the head, where it branches into au

upper limb, running to the postaural fold, but terminating some distance from its free

edge (PI. 25. tig. 3), and a lower, which serves to separate the ramal from the inter-

ramal areas of the pt. capitis.

Apt. trunci laterale (PI. 25. fig. 2). — Arising at the shoulder, it serves to divide the

humeral fi-om the spinal tract, and is continued baclovards to the tail, and thus separates

the spinal from the femoral tracts. At the free edge of the axillary fold it runs down-

Arards to embrace the whole side of the bodv. Its extreme ventral limit is bounded bv

the inner border of the pt. ventralis.

Apt. spinale (PL 25. fig. 1). — This is the space enclosed by the brandling arms of the

upper and lower portions of the pt. spinalis.

Apt. mesogastrcei (PL 25. fig. 3). — The dimensions of this space can be seen at a

glance in the figure.

Apt. crurale. — This is the space at the l)ack of the leg (p. 231), and is continued

downwards on the tarso- metatarsus.

Aft. alee superioris. — The space dividing the humeral from the wing-tract.

Apt. al(B infei'ioris. — Embraces the bare region of the arm and patagium.

Asio OTUS, Linn.

Pt. capitis : —

Fronto-parietal are a. — The feathers forming the " ear "-tufts are distinct from

the general j)lumage of the head, and consist of a longitudinal row of some 7-8 feathers,

bounded on either side by an apterion.

Loreal are a. — Sharply defined; upper limb free,more slender than in A. accipitrinus.

I n t e r r a m a 1 are a. — The anterior symphysial portion shorter antero-posteriorly

than in A. accipitrimiH ; the posterior portion joining the feathers of the ramal area on

(.'ither side.

Pt. colli dorsalis. — The lateral neck-folds gradually tapering backwards, and not

suddenly expanded just behind the head. With a retractor muscle.

Pt. spinalis. — Interscapular fork commencing at the confluence of the j^t- colli dorsalis

and p>t. spinalis. The free ends of the intersaipular fork are received into the arms of

the lumbar fork, which are continued outwards on the posterior patagial membrane as in

A. accipitrinus. The tract l)ifurcates posteriorly, embracing, but not surrounding, the

oil-gland.

Pt. colli veniralis.—Yerj broad at the point of bifurcation.

Pt.fehioralis. — Femoro-crural band terminating at the base of the patella.

Pt. ventralis. — Inner branch somewhat nearer the middle line than in A. accipitrinus.

MOEPHOLOGY OF THE OWLS. 235

Pi. alaris. —

Tectrices : —

T. majores. — The dorsal major coverts show an interesting departure from the general

rule, in that, instead of the break in the uniformitj' of the length of these coverts

occurring after the 5th covert, it occurs after the 4th, the 5th being slightly shorter

than the 1th, but, as usual, longer than the 6th.

T. medue. — The break in the uniformity of the length of the coverts is here very

marked, the 6th covert being much sliorter than the 5th.

T. minores. — The remarks apply to the first two rows of these coverts as to T. medics ;

in the 3rd row the differeace is not so marked.

Such other points as are unnoticed are indistinguishable from A. accipitrinns.

Bubo ignavus, Torst.

Pt. capitis : —

F r 0 n t o - p a r i e t a 1 arc a. — The two areas included under the name can here be

readily distinguished. The frontal area is represented by a broad median band of feathers

running from the base of the beak to a point corresponding with a line drawn across

the head behind the eyes, where the tract rapidly expands to form the parietal area.

This distinction is not so readUy seen in the case of B. viaculosus on account of the

smaller size of the feathers.

The feathers forming the ear-tufts, in a single row, l)ounded posteriorly by an apterium,

the anterior exti'emity of the ((pt. colli laterale.

C i r c u m a u r a 1 area : —

P r e a u r a 1 f o 1 d. — This is but slightly developed ; there is a double I'ow of feathers

along its free edge, the bases of Avliich form a " rim."

Postaural fold. — The upward and downwardly directed feathers along its free

edge converging at about the middle of the fold, the bases of which form a " rim." The

peripheral disc-feathers terminating on the mandible, just in front of the gape.

Ocular area. — The rows of feathers encircling the region of the outer wall of the

eye can be well studied in this species.

Loreal area not sharply defined, the lower limb continued backwards to join the

feathers at the confluence of the opercular and circmuaural folds.

Ramal area not extending to the proximal end of the jaw, but turning inwards in

the form of a narrow baud on the throat.

Interramal area. — In the form of a broad tract, bounded on either side by a

wide apterium.

A^it. colli laterale. — Continued upwards from the neck on to the proximal end of the

mandible ; Jrom thence it can be traced upwards and forwards on to the crown, where it

serves to isolate the row of feathers forming the " ears." The continuity of the space is

interrupted, however, by two tracts of feathers, one running from about the middle of

the postaural fold, the other from the region immediately above the fold, to the feathers

of the occipital area.

230 MR. W. P. PYCRAFT ON THE

Ft. colli dorsalis. — Vertical and lateral neck-folds moderately well developed. No

retractor muscle.

Ft. sinnalis. — Branches of the interscapular fork arising- at the commencement of the

interscapular region ; arms long, hut not extending to the end of the scapula.

Branches of the lumhar fork arising about midway between the anterior end of the

ilium and the region over the acetabulum, running forwards to embrace the ends of the

interscapular fork, and terminate over the proximal f of the free end of the scapular.

Stem forked posteriorly, branches widely divergent, terminating some distance to the

outer side of the oil-gland.

Pt.ventralis. — Outer branch strongly developed, arising at the summit of the shoulder.

Median branch broad, very strong, with an upward trend at its free end, where it gives

off the " hook." Inner branch wide, not sharply defined at its upper end ; the breast

between the median branch and the carina being almost continuously feathered.

Pt. humeraUs not continued forwards to johi the Ft. ventrcdis.

Ft.femoralls. — The femoro-crural band terminating on the crus some distance below

the knee.

Pt. cruralis. — Continued downwards on the acrotarsium and terminating on the acro-

pcdium. The base of the ungual phalanx clothed with scales. Proximal end of the

planta bare.

Bubo virginianus, Sw. & Rich.

Pt. capitis : —

Parietal are a. — " Ear "-tufts very distinct, the stumps of the feathers appreciably

larger than those of the neighbouring feathers. They are seven in number, arranged to

form a longitudinal row, the inner border of which is bounded by a large lenticular

apterium.

Loreal are a. — Upper limb not continued vipwards beyond the level of the anterior

corner of the eyelid.

Circum aural area. — Preaural fold feebly developed, a double row of feathers

along its free edges ; a broad apterium separating these from the ocular area.

Postaural fold.- — The convergent feathers along the fi'ec edge of the postaural

fold meeting near its middle. The feathers behind the free edge arranged in the form of

a triangular patch. Peripheral disc-feathers arising on the crown of the head just behind

the eye, terminating on the mandibular area.

Mandibular area. — Extending beyond the articular end of the mandible, very

broad, at the level of the gape turning sharply inwards to merge with the feathers of the

interramal area.

Inter ramal area. — Very broad, at the level of the gape merging with the ramal ai*ea.

Apterium colli laterale. — Extending on to the postaural fold and skirting the

articular area of the lower jaw. Passing Ijehind the triangular patch of the postaural

fold iipwards, it attains the level of its superior angle, but is cut off by a broad band of

feathers from the lenticular apteria to the inner side of tlie " ear "-tufts.

MOEPHOLOGY OF THE OWLS. 237

Ft. colli dorsalis. — Lateral neck-folds considerable ; with a retractor muscle as in

Asio.

Ft. spinalis. — Arms of the interscapular fork arising- about the middle of the inter-

scapular region ; branches short, running almost parallel, not widely divergent, extending

to the end of the scapula.

Lumbar fork. — Arising behind the middle of the preacetabular region of the

ilium; well developed, extending forwards on to the axillary membrane. Stem cleft

posteriorly into two long arms, not extending to the oil-gland.

Pt. colli veutraUs. — As in the other si^ecies of Bubo, branching about the middle of

the neck to join the Pt. ventralis at the shoulder.

Pt. ventralis. — Outer branch strong, arising low down from the outer border of the

median branch. Median extending backwards as far as the posterior f of the carina

sterni. Inner branch broad, but more sharply defined than in B. maximus or B. lacteus.

Pt. alaris : —

Bemiges. — Metacarpo-digital 11 ; cubitals 19 ; the innermost 2-3 cubital remiges

scarcely differing in size from their coverts.

Tectrices : —

T. nuijores. — The major coverts of the dorsal surface vmiform in length.

T. medicc. — With a distinct break in the uniformity of the length of the series, the

6th being much shorter than the 5th.

T. minores. — With a l^reak in each row, similar to that seen in the T. medice.

Parapteron. — Made uj) of some 10 obliquely-transverse rows sloping from without

inwards. Each row composed of 4 feathers, the most postaxial a semiplume, and over-

lapping the next, a true contour -feather, and much longer ; this in turn overlaps the

one next above and longest of the series, which is overlapped by the most preaxial

feather. Proximally these humeral feathers rest upon the muscles of the arm; distallv,

upon the humerus ; running along the upper surface of the humerus is a row of

semiplumes, all with the tips directed towards the tip of the wing.

Between each of the transverse rows just described, and on the extreme postaxial

border of the humerus, are two semiplumes, one lying a little above the other. The

uppermost one runs parallel with the lai-ger feathers of the parapteron; the lower is

pressed close to the arm, Avith its tip directed towards tlie end of the wing. Whether

these feathers are really serially homologous with the dorsal and ventral major coverts

and the dorsal row of median coverts, and a ventral row of minor coverts, as represented

by the semiplume, or not, remains to be proved. It will be noted that in this case the

x-emiges are wanting.

The coloration of the feathers of the parapteron is not to be distinguished, save in

minute points of detail, from those of the fore arm.

Hypoptei'on. — Three parallel rows along the arms, somewhat semiplumous in texture.

Pt.femoralis. — Femoro-crural band terminating considerably below the knee.

Pt. eruralis. — Toes thickly feathered. Terminal phalanx covered by 3 broad scutes.

238 ME. "W. P. PTCEAPT ON THE

Bubo MACULosrs, Bp.

Ft. capitis : —

iPronto-parietal area. — The feathers formmg the " ear "-tufts in a single

longitudinal row on the crown of the head, with a w ell-markcd apterium on either side.

Loreal area. — Not sharply defined; vipper limb scarcely extending beyond the

anterior corner of the eyelid.

Circumaural area. — The preaural fold is but feebly developed, and does not

Ibrm an operculum. It bears but a double row of feathers along its free margin, the

bases of which form a " rim " to the margin.

The feathers of the postaural fold seated along the free edge of the upper part are, as

usual, all directed downwards, those of the lower part upwards, the two series meeting in

the middle of the fold. There is no " rim " to this fold.

The peripheral disc-feathers apparently terminating below on the mandible, near the

base of the rhamphotheca.

Ramal area. — Truncated posteriorly, not extending backwards to the proximal end

of the jaw.

Interramal area. — Wide anteriorly, gently tapering joosteriorly to join the

ft. coll. ventralis.

Apt. colli laterale. — Occupying the lower portion of the circumaural fold, and

running upwards and forwards behind a triangular patch of feathers clothing the upper

part of the Ibid, to cut off the row of feathers forming the " ear "-tufts from the rest of the

parietal area.

Pt. colli dorsalis. — Vertical and lateral neck-folds of slight extent ; the posterior end

of the tract where it joins the^^. spinalis 4 feathers in width.

Pt. spinalis. — Branches of the interscapular fork arising in the middle of the inter-

scapular region ; arms not extending to the free end of the scapiila.

Branches of the lumbar fork arising about midway between the anterior end of the

ilium and the acetabular. Strongly developed, embracing the ends of the interscapular

fork, crossing the free end of the scapula, and terminating on the axillary membrane.

Stem strong, broad, bifurcated posteriorly, but not reaching the oil-gland.

Pt. ventralis. — Outer branch broad, arising at the summit of the shoulder.

Median branch not extending backwards beyond the level of the upper ^ of the carina

sterni. It is very sharply defined, with an upper trend at its free end. Its great

distinctness seems to cut it off from the recurved branch or " hook " characteristic of tliis

portion of the tract.

Inner branch arises rather above the middle region of the clavicle, and follows the

covirse of that bone up to the carina sterni ; running along the upper end of this for a

short distance, it turns rapidly outwards and backwards to the region over the posterior

lateral process of the sternum ; from this point it runs backwards to join its fellow in

the middle line a short distance in front of the cloacal aperture.

Pt. humtralis not running forwards to join the ft. ventralis.

Pt. alaris. — Eemiges too abraded and broken to be of use for comparison as to

length, &c.

MOEPHOLOGT OF THE OWLS. 239

Tectrices : —

T.majores. — Dorsal major coverts of tlie cubital remiges unfortunately moulting. The

6th covert not fully developed in one wing and absent in the other. In both wings,

however, the old 5th and 7th coverts remain, and furnish a point of interest in that the

5th is considerably shorter than the 7th. The coverts from the 7th inwards gently

decreasing in leng th

T. medics. — The dorsal median coverts increase rapidly in length from 1-5, and are

the longest in the row. The 5tli is considerably longer than the 6th.

T. minores. — The dorsal minor coverts resemble the median in that 1-5 in each row are

longer than the feathers lying proximally ; the difference is less marked in each row

from behind forwards.

Parapteron and Hypopteron, se-e Bubo virginianus (p. 236). The description is from a

fresh specimen from the Zoological Gardens, and therefore better for study than in the

present species — a spirit sjiecimen.

Pt.femoralis. — Femoro-crural band terminating some distance below the knee.

Ft. cruralis. — Continued downwards on to the acrotarsium and acropodium. In the

latter region the feathers are not sufficiently large to conceal the skin. Base of the

terminal phalanx clothed with scales.

Jxliamphotheca. — The cere having the anterior margin sharply defined against the

culmen, much as in Accipitres, slightly swollen immediately around the external

aperture of the nostrils.

TJropygium. — In form of an elongated cone, bearing 3 apertures at the tip.

Bubo lacteus, Steph.

Fteryla capitis : —

Fronto-parietal are a. — Resembles in general conformation that of B. ignavus,

but not so sharply defined. The cut bases of the " ear "-tufts not easily distinguishable

from the rest of the feathers of the head.

Ramal are a. — Very broad posteriorly, encroaching upon the throat ; not continued

backwards so far as the proximal end of the mandible.

Inter ramal are a. — Connected with the ramal by two separate lateral branches,

one some distance behind the region of the gape, the other near the articulation of the

jaw.

Best of the feathering of the head almost identical with that of B. ignavus.

Apt. colli laterale. — Extending upwards and forwards in the form of a long narrow

space behind the postaiu'al fold, terminating about its ixdddlc. It is cut off by a broad

baud of feathers from the small apterium lying to the inner side of the bases of the

ear-tufts.

Ft. colli (lorsalis.— With, vertical and lateral neck-folds slightly developed, less than

in B. maximus.

Ft. spinalis. — Interscapular fork arising in the upper fourth of the interscapular

region ; the arms extend to the end of the scapula.

Lumbar fork arising rather below the middle of the preacetabular part of the ilium ;

SECOND SERIES. — ZOOLOGY, VOL. VII. 33

240 MR. W. P. PYCEAFT ON THE

its arms extend outwards on to the axillai-y memhrane, bet\yeen the x>t- liumeralis and

the scapula. Stem forked posteriorly, so as to embrace Imt not surround the oil-gland.

Ft. ventral is.— Outer branch very strong, arising low down, over the dorsal third of

the furculum.

Median branch narrower and more sharply defined than in B. maximus, extending

backwards to the level of the posterior third of the carina sterni. Not recurved at its

posterior end, where it passes into the " hook."

Inner branch arising from the median rather about its middle ; more sharply defined

than m B. maxlmus.

Pt. alaris : —

Bemiges. — Metacarpo-digitals 11 ; cubitals 19.

Tectrices : —

T. majores. — The dorsal major coverts of the cubital remiges liaving the 5th slightly

shorter than 4th, ))ut longer than the 6tli. 5th and 7th equal.

T. medi(B. — 1-5 longest in the row ; 6 abruptly shorter than 5 ; from 6 inwards

gradually increasing in length.

T. minores. — The same remarks apply to these feathers as to the t. medicB. There are

three rows of minor coverts.

Pf.femoralis. — IFemoro-crural band terminating below the knee.

Pt. cruralis. — Toes bare, but beset with stumps of old feathers worn down to surface

of skin. Terminal phalanx having the base covered with scales.

Bubo toequatus, Daud. {Syrnium iJerspicillatum, Lath., of Sharpe's Catalogue, p. 277.)

Pt. capitis : —

Pronto- parietal are a. — Frontal area in the form of a broad well-defined band,

rapidly expanding above and rather behind the eyes to merge with the parietal area.

Loreal area. — Ill-defined.

Inter ramal area expanding in the region of the gape to join the ramal area,

which does not extend backwards to the end of the jaw.

Periphery of the disc ill-defined.

Pt. colli laterale. — As in Bubo.

Pt. colli dorsalis. — Lateral neck-folds very slight, tract narrow.

Pt. colli ventralis. — Divides about halfway down the neck.

Pt. spinalis. — Interscapular fork arising in the upper third of the interscapular region ;

arms narrow, extending to the level of the end of the scapula. Branches of the lumbar

fork arising near the anterior border of the ilium ; short, running out on to the axillary

membrane.

Pt. ce^itralis. — Outer branch well defined, arising at the summit of the shoulders ;

median long, narrow, not curved terminally (as in Syrniuni) ; inner branch broad,

sharply defined from the median, and, rising near tlie summit of the shoulder, joins its

fellow of the other side just in front of the cloacal aperture.

Pt. femo)'alis. — Pemoro-crural tract terminating at the knee-joint.

MOEPHOLOGY OP THE OWLS. 2il

Rhamphotheca. — Cere of considerable size, slightly inflated at the base ; aperture of

the nostrils circidar, looking slightly downwards.

Podothcca. — Acrotarsium feathered. Acropodium covered with warty protuberances.

Terminal phalanx with the base sheathed by three scales.

Uropygium. — The oil-gland is conical, as in Bnho-

The pterylosis closely resembles that of Buho maculosus, but the vertical and lateral

neck-folds are much less in extent than in this species. Bubo torquatus * and Syriiium

aluco compared together prove conclusively the affinities of the former with Bubo rather

than with Syniium, with which it appears to have been generally associated.

Bubo nyctekus, L. {Nyctea scandiaca, PI. 26.)

Fteryla capitis : —

P r 0 n t a 1 area shorter and wider tlian in Bubo ; it is also much arched.

Parietal area. — Feathers of the " ear "-tufts in a single longitudmal row, some 6

in number ; their bases conspicuously larger than those of the surrounding feathers, and

hounded on the inside by an elongated lenticular apterium.

Loreal area merging above with the frontal are;i.

Circumaural are a. — Preaural fold feebly developed, with a double row of feathers

along its free edge. Postaural fold as in Bubo, e. g. B. igiiavus. The periphery of the

disc, as demarcated by the cut Ijases of the feathers, arising just above the postaural

lold, rather helow the level of the toj) of the eye, runs dowmvards and forwards along

the postaural fold on to the mandible, terminating midway between the gape and the

rhamphotlieca.

Ramal area extending backwards to the articular end of the jaw; bi-oad poste-

riorly, exteading downwards to join the interramal tirea.

Inter ramal area. — The anterior end giving off a narrow lateral branch on each

side, at right angles to the main axis of the tract, from the region rather in front of the

angle of the gape ; behind this the tract is constricted, expanding again immediately

after to join the hinder end of tlie ramal area.

Apt. colli latenUe extending forw ard on to the base of the postaural fold, but entirely

cut oh' from the apterium at the base of the feathers of the " ear "-tufts.

Pt. colli dorsalis very broad anteriorly. Vertical and lateral neck-folds considerable.

Pt. spinalis. — Interscapular fork arising in the upper fifth of the interscapular region.

Arms long, wide apart, extending to the end of the scapula, and almost joining the arms

of the lumbar fork, so as to enclose a space.

Lumbar fork. — Arms sharply defined (PL 26), arising in about the middle of the

preacetal)ular region of the ilium ; they extend forwards on to the axillary membrane,

meanwhile expanding so as to assume a conical form. Stem sharply defined, broad

posteriorly, forked, the arms wider apart than the width of the oil-gland and terminating

in front of this.

* Cf. footnote at bottom of p. 270.

242 ME. W. P. PYCEAFT ON THE

Pt. ventralis. — Outer branch distinct, arising rather below the summit of the shoulder.

Median broad, terminating at a jioint corresponding with a line drawn through the carina

sterni at its middle. Inner branch broad, arising about halfway down the inner side of

the median branch. Nowhere sharply defined on the breast, but very distinct on the

abdomen.

Pt. alaris : —

Bemiges. — Metacarpo-digitals 11. Cubitals 18.

Tectrlces : —

T. majores. — Coverts 1-5 of the dorsal surface longest, 6 slightly shorter than 5, 7

equal in length to 5.

T. medice. — Damaged.

T. minores. — Three rows. All showing an abrupt break in the length of the feathers in

each row. 1-5 always considerably the longest.

Pt.fcmoralls. — Fcmoro-crural band terminating some distance below the knee.

Pt. cruraUs. — Continued downwards over the acrotarsium on to the acropodium, termi-

nating behind the ungual phalanx, the base of which is clothed by scutes. The feathers

on the acrotarsium and acropodium very long, half concealing the claws. Planta bare in

region of tarsal joint only.

Tlropyglmn. — In the form of an elongated cone, slightly swollen at the base.

All the tracts are very narrow, but the feathers are of great length ; a humeral feather

measured 8 in. from lower umbilicus to tip, and one from the median branch of the

pt. ventralis 7 in.

c OPS LEUCOTIS, Temm.

Pt. capitis : —

Fronto-parietal area. — Feathers of the " ear "-tufts or "horns" in 2 longi-

tudinal rows of about 5 feathers in each. Their massed bases are surrounded by an

apterium, except anteriorly, where they merge with the broad band of feathers occu-

pying the median line of the head, thus tending to form short brandies to this band.

Loreal area. — Moderately well defined, crescentic in form, the upper limb longest

and terminating above the region of the middle of the eye. Feathers of great length.

Circumaural are a. — The preaural fold feebly developed, not forming an oper-

culum. A double row of feathers runs along its free edge, the bases of which form a

" rim " ; in front of this is a single row set in an apterium, as in Asio accipitrinus (p. 229).

The bases of the feathers along the free edge of the postaural fold also form a "rim,"

as in Asio &c.

Interramal area. — Very wide posteriorly, merging with the mandibular area

from the gape backwards, rapidly contracting on the upper part of the neck, where it

becomes the pt. colli ventralis.

R a m a 1 are a. — Broad, extending backwards beyond the end of the mandible.

Lateral cervical apterium terminating at the base of the lower half of the circumaural

fold (PI. 26).

MOEPHOLOGY OF THE OWLS. 243

Pt. colli dorsalis. — With a slight lateral skin-fold : no retractor muscle.

Pt. spinalis. — Ai'ms of inter sea j)ular fork ai-ising- rather ahove the middle of the inter-

scapular region, not widely divergent, but running almost parallel, terminating at the

end of the scapula. Branches of the lumbar fork arising midway between tlie anterior

end of the ilium and the acetabulum ; widely divergent ; base of the stem forked poste-

riorly, so as to embrace the oU-gland.

Pt. ventralis. — Outer branch feeble ; median strong, recurved ; inner relatively broad

and strong, arising just in front of the region of the anterior end of the carina of the

sternum, terminating in front of the cloacal aperture.

Pt. Inmieralis continued forwards to form the jd. ventralis at the summit of the

shoulder.

Pt. alaris : —

Tectrices majores. — The 5th cubital covert of the dorsal surface slightly shorter than

the 4th, but equal in length to the Gth.

T. media;. — The 5th cubital covert of the dorsal surface much the longest in the series,

the feathers rapidly lengthening from 1-5 ; Gth much shorter than 5, slightly shorter

than remaining proximal coverts. The proportions of the rest of the coverts much as

in A. accijntriiius.

Pt.femoralis. — Ecmoro-crural baud terminating over the distal end of the femur

above the knee-joint.

Pt. o'uralis. — Acrotarsium covered with relatively short feathers. Feathers on the

acropodium scanty, degenerated, confined strictly to the upper surface ; sides of toes

bare, covered with granulated skin ; base of ungual phalanx covered by three scales.

Rhamiihotheca. — Cere very short, much inflated. Nostrils pierced in its anterior

border; aperture circular, looking directly forwards, and not laterally, as in other Owls.

UrojJi/giiim napiform, with a tendency to a conical form, as in Buho.

Scops giu, Scop.

Pteryla capitis : —

Loreal area not qviite so well defined as in S. leucotis, and the feathers not

elongated as in that species.

Interramal area with a narrow branch running obliquely backwards to join the

ramal area behind level of the gape.

E, a m a 1 area narrow, not extending backwards beyond the end of the mandible.

Pt. colli dorsalis -with a lateral skin-fold and a short retractor muscle crossing the

neck obliquely.

Pt. s/j/»a//s.— Interscapular fork as in S. leucotis. Lumbar fork with the branches

rising near the anterior border of the ilium and dividing at the base into two rows of

semipluiues, one of w^hich runs out on to the axillary membrane, and one is continued

upwards to join the free ends of the interscapular fork, enclosing an oval apterium.

Pt. alaris : —

Tectrices majores. — The 5th cubital covert slightly shorter than the 4th, but longer

than the Gth.

244 ME. W. P. PYCBAFT ON THE

Pt. femora J is. — Femoro-criiral band terminating below tbe knee-joint.

Rhamphotheca. — Cere somewhat longer antero-postei'ioi-ly than in S. leucotis, and with

a slight lateral swelling.

Podotheca. — Acropodium covered Avith small round scales.

TJropygium napil'orm, with a long tubular extremity resembling that of Qarine.

NiNOX NOV^-ZEALANDI^, Gm.*

Pteryla ccqntis : —

L o r e a 1 area ill defined.

C i r c u m a u r al area : —

Postaural fol d. — The feathers along the free edges of this fold seated in a double

row, the massed bases of which form a " rim."

Interramal area suddenly contracting in the region of the gape, to pass back-

wards into the p)t- coll. ventralis.

Apt. colli laterale terminating at the base of the postaural fold.

Pt. colli dorsal/s with a distinct vertical membranous fold; lateral folds very small.

Pt. spinalis. — Branches of the interscapular fork arising in the middle of the inter-

scapular region, short, terminating at the end of the scapula.

Branches of the lumbar fork arising over the anterior ends of the ilium, not widely

divergent, but received between the branches of the interscapular fork. The stem is

forked posteriorly, but the branches are not sufficiently wide apart to embrace the

oil-gland.

Pt.femoraUs. — Femoro-crural band extending on to the ceres and turning upward to

terminate at the femoro-tibial articultition.

Pt. cruralis. — Acrotarsium thickly feathered ; acropodium covered with warty pro-

tuberances bearing degenerate feathers, the shafts only of which remain. Filoplumes

absent. Base of the ungual phalanx clothed with three scales.

Jlhaniphotheca. — Cere laterally inflated, resembling that of Scops.

Podotheca. — Claws short and blunt. Tylari of Digit II. large.

Vropycjlum napiform, with conical tendency.

ScELOGLAUX ALBIFACIES, Gray t.

Pt. capitis : —

Loreal area not extending upwards above the eye.

Interramal area broad, expanding to merge with the ramal area at the gape.

Cir cum aural area. — Preaural and postaural folds with a rim; no "notch" in

the rim of the postaural fold.

Apt. colli laterale terminating on circumaural fold, not extending on to the head.

? No parietal apterium. A large apterium above upper eyelid, as in other Owls.

* This description is taken from a plucked specimen.

t Examined frum a skin kindly lent by Prof. A. Newton, from tbe Cambridge University Museum.

MOEPHOLOGT OF THE OWLS. 245

Pt. sjmialis.— Arms of interscapular fork long, arising higher up, not widely divergent.

Stem of lumbar fork veri/ wide. Seven feathers, forked posteriorly. Arms short,

Fis. 1.

.if.

Portion of the upper end of the lumbar fork of SceIo(/lau.r alhifiicies, to show the extreme breadth of the

stem and short arms. i.f. Interscapukir fork. l.f. Lumbar fork.

closely approximated, running almost parallel, at their distal ends expanding, so as to

clothe the axillary membrane.

Ft. veil trails.— Inner branch not sharply differentiated from median, distinguishable by

reason of their more sparse distribution and semiplumous character. They form a

narrow band on the abdomen.

Apteria generally thickly sprinkled with semiplumes.

Perhaps the most characteristic feature of the pterylosis of Sceloglaux is the great

width of the stem of the lumbar fork.

Mhamphotheca. — Cere slightly swollen ; nostril pierced in its anterior margin.

Podotheca. — Feathers on the acropodium reduced to bristles. Scales on the acropodium

more distinct than on the acrotarsium. Claw^. — The inner side of the claw of the middle

toe with a flange.

Syrnium alitco, L. (PI. 26.)

Pteryla capitis : —

Loreal are a. — Upper limb continued backwards to join the confluent feathers of

the pre- and postaural tracts.

C i r c u m a 11 r a 1 are a. — The preaurai fold is well developed and forms an operculum

(see p. 229 and PL 28- figs. 1-2). It supports numerous strong, well-developed feathers,

arranged in 4 jmrallel semicircular rows ; rows 1 and 2 are bound closely together, their

bases forming a rim to the free edge of the fold ; rows 3 and 4s are placed further

forwards. At some distance from the most anterior row, and separated by an apterium, is

a single row running from the gape, backwards and iipwards, to the anterior corner of

the base of the oiwrculum. This row is with difficulty distinguished anteriorly from the

feathers of the ocular area.

Postaural fold almost as cxtens.ive as m A. acci2)itrinHS. Likewise the feathers

seated along its free edge are densely packed, and their bases form a rim to the free edge of

246 ME. W. P. PTCEAFT ON THE

the fold. These feathers help to form the periphery of the disc, which is continued down-

ward and forward to join its fellow of the opposite side heneath the jaw^ (PI. 26).

Ramal area extends from the rhamphotheca of the lower jaw backwards to the

level of the region where the opercular and postaural folds coalesce. The peripheral

disc-feathers divide it into an upper and a lower portion (PL 26).

Interramal area broad, sending off on either side a single row of feathers to join

the H a m a 1 area in the region where it merges with the pt. colli ventralls.

Apt. colli laterale extending on to the circumaural fold as far as the peripheral disc-

feathers ; from its upper border, bounding the pt. colli dorsalis, it is continued as a very-

slender space on to the pteryla capitis, terminating at a point somewhat behind the level

of the region where the anterior ends of the pre- and postaural folds coalesce.

Pt. colli dorsalis tapering from the head backwards. Lateral neck-folds of sUght

extent ; wdthout retractor-muscles.

Pt. spinalis. — Branches of the interscapular fork arising about halfway dowTi inter-

scapular region ; arms short, 3 feathers in width, not extending to the end of the scapula.

Branches of the lumbar fork represented ])y a single row of feathers arising far forward

on a level with the ends of the scapula ; they embrace the arms of the interscapular fork.

The stem of the fork bifurcated posteriorly, but terminating short of the oil-gland.

Pt. ventralis. — Outer branch joined to the median by a single row^ of feathers, abruptly

expanded near its middle to 3 feathers in width. Median branch broad, with a strong

recurved limb springing from its free end — the " hook." Inner bi-anch broad, arising

from the median at the point where the latter passes over the acrocoracoid region from

the neck ; it follows the course of the furculum for some distance, then runs backwards

to join its fellow of the opposite side in front of the cloacal aperture.

Pt. humeralis. — Not connected anteriorly witli tlie pt. ventralis.

Pt. alaris : —

Metacarpo-digital remiges 11 ; the 11th a remicle, very small, little more than half as

large as its dorsal major covert ; the 6th remex the longest, giving the wing a short,

rounded appearance: the 5th to the 9th remex having the distal end of the outer vane

more or less emarginate ; outer vane of 10th serrate.

Cubital remiges 15.

Tec trices : —

T. major es. — Those attached to the dorsal surface of the cubital remiges of uniform

length, save the 6tli, which is distinctly shorter than the 5th or 7th.

T. medicr. — 1-5 of the cubital remiges of the dorsal surface gradually increasing in

length, and distinctly the longest in the row.

T. minores. — 1-5 of each row of the dorsal minor coverts markedly longer than the

remainder of the coverts of their respective rows.

Pt.femoralis. — AVell developed; femoro-crural baud strong, terminating on the crus,

a short distance below the knee.

Pt. criiralis. — Continued downwards over the acrotarsium and acropodium ; feathers

long and thickly placed. Plauta having the proximal end bare. Penultimate phalanx

of toes scale-covered.

MOEPHOLOGY OF THE OWLS. 247

'Rhami^hotlieca. — Cere of considerable extent, very slightly inflated.

Podotheca. — Claws rounded, not much curved.

TJropyglmn. — Napiform, with a very marked tendency towards the elongate-conical

form of the Buboniuas.

Strnium uralense, Pall.

The pterylosis of this species differs only in the following details from S. aluco.

Pteryla capitis : —

Inter ramal area. — With a lateral branch rimning at aright angle to join the

ramal area in the region of the gape, as in S. aluco. A short distance behind this lateral

branch it forms a broad expansion merging with the ramal area.

Apit. colli laterals. — Extends upwards and forwards to the level of the angle of the

exoccipital wing of the tympanic.

Ft. spinalis. — Branches of the lumbar fork rising near the anterior border of the

ilium, not widely divergent, running up to, but not quite joining, the free ends of the

branches of the interscajmlar fork, thus enclosing a median s^iace. The stem not

extending backwards so far as in ^S*. aluco, but terminating some distance in front of the

uropygium.

Pt. alaris. — The 6th major covert of the ciibital series shoi'ter than the 5tli ; the

remainder of the other coverts moulting. " Carpal remex " penuaceous, as large as its

covert, thus differing from that of S. aluco, in which this feather is semiplumous and

markedly smaller than its covert.

External aperture of the ear symmetrical, its vertical axis slightly longer than the

longitudinal axis of the closed eyelid.

Uropygium. — Napiform, with a long terminal tube.

Ntctala tengmalmi, Gm.

Pteryla capitis : —

Loreal area. — Not sharply defined, with an apterium at its base, almost dividing

the area into two portions, an interior and a posterior, the former including the greater

part of the area. The apterium, which is very narrow, arises in the region in front of

the eye, on a level with its anterioi- corner, and runs downward and then upward so as

to partly encircle the eye, terminating rather above the level of its posterior corner.

This apterium differs from that of Speotyto in that it fails to divide this area into two,

in that it is less wide, and in that the posterior semi-detached patch is much less in size

C i r c u m a u r a 1 are a. — The bases of the feathers seated along the free edge of the

preaural fold form a rim ; lying in front of, and parallel with the rim, is a single row of

feathers — as in Asio — banded on either side of the apterium.

The feathers running along the free edge of the postaural fold are densely packed, their

bases of insertion forming a " rim " to the fold. From the base to within a short

distance of the superior limb of the fold the feathers seated on this free edge are directed

second series. — ZOOLOGY, VOL. VII. 31

248 ME. W. P. PTCEAFT ON THE

obliquely upwards ; the rest ai*e directed downwards ; heace the notch in the rim of the

fold (PL 27. figs. 5-6).

The j)eripheral disc-feathers (p. 236) are continued downwards and inwards to meet in

the middle line a short distance behind the symphysis of the mandible.

1 n t e r - r a m a 1 are a. — Cut into two by the meeting of the peripheral disc-feathers ;

the posterior portion somewhat triangular in form, its base planted against the confluent

peripheral disc-feathers, its tapering apex merging with tlie pt. colli nentralis.

Apt. colli laterals terminating at the base of the circiimaural fold.

Pt. colli dorsalis with considerable A'ertical and lateral neck-folds. The tract

decreasing rapidly in width from before backwards.

Pt. sjniialis. — Interscapular fork bai'ely percejotible (PL 26).

The lumbar fork, so far as my specimens are concerned, has the branches very feebly

developed and disconnected at their bases from the main stem. This last is continued

forwards so as nearly to join the interscapular fork (PI. 26).

Pt. colli ventralis. — Very narrow at its upper end, where it joins the interramal area ;

sends off two branches at the middle of the neck to join the pt. ventralis at the shoulder.

Pt. ventralis. — Outer branch well developed ; median strong, recurved ; inner strong,

not meeting its fellow in the middle line in front of the cloaca, but terminating over the

free end of the pubis.

Pt. Immeralis. — Not continued forwards to join the pt. ventralis.

Pt. alaris : —

Tectrices : —

T. majores. — The dorsal coverts of the cubital remiges of uniform length, save the 6th,

which is much shorter than the coverts on either side. The same proportions appear to

obtain in the t. medice and t. minores.

Pt.femoralis — Femoro-crural band turning sharply upwards to terminate over the

distal end of the femur.

Pt. crtiralis. — Aerotarsium and acropodium densely and thickly feathered ; penultimate

phnlanx clothed with 3 scales.

Phamphotheca. — Cere short, inflated, closely resembles that of Speotyto.

TJropyginm. — Small, napiform, but the pointed extremity very short, making the gland

almost triangular in form.

Stjrnia ulula, Linn.

Pteryla caintis : —

Interramal are a. — Expanding at the gape to join the ramal area.

Apt. colli laterale. — Terminating on the jiostaural membrane.

Pt. colli dorsalis. — With an oblique membranous fold, from the pt. colli dorsalis to

the centralis, similar to that of Asio, but more feebly developed.

Pi. spinalis. — Interscapular fork barely perceptible ; the tract, which is broad, termi-

nating midway down the interscapular region. The posterior moiety of this tract has a

very broad anterior end, not differentiated into branches.

MORPHOLO&T Oi^ THE OWLS. 249

Ft. ventralis. — The median branch is very broad posteriorly.

Pt. alaris : —

Tectrices. — The major coverts were moulting.

T. medice. — The 6tli median cubital covert was much shorter than the 5th, as usual.

T. minores — The same remarks apply to this series as to the t. medice.

Pt.femoralis. — Femoro-crural band terminating at the knee-joint.

Bhamplwtheca. — Cere short, slightly inflated.

Podotheca. — Densely feathered.

TJropygium. — Napiforin.

Speotyto cunicularia, Molina.

Pteryla capitis : —

Loreal area. — Divided by an ajitei'iuin into two portions: an anterior, running

round the base of the bill, and a posterior, encircling the anterior region of the eye.

This latter is continuous at its lower posterior angle, immediately above the gape, with

a single row of feathers running round the base of the lower eyelid and upwards to its

posterior corner. The loreal apterium separates this row from the feathers of the ramal

area.

O c u 1 a r a r e a. — The single row of feathers above described as forming a continuation

of the lower limb of the loreal area forms the lowermost boundary of this area. Above

it, separated by a broad apterium, is another single row of feathers ; above this are two

other rows, each separated by an apterium. The upper eyelid is clothed witli numerous

rows of small, downy feathers. A. very considerable crescentic apterium sejiarates the

uppermost rows from the featliei's of the fronto-parietal area. The rims of the eyelids

are fringed with some 3 rows of feathers, decreasing rapidly in size as they approach the

free edge. The hindmost are characterized by the production of the shaft outwards beyond

the vane. In the outermost, nothing but the shafts remains, and these form " eyelashes."

Circumaural fold : —

Preaural fold (PL 28. fig. 5). — This fold is very feebly developed. Along its

free edge is a single row of elongated narrow-vaned feathers. They are somew^hat

curved, the concavity being turned towards the head so as to form a feathery operculum.

Postaural fol d. — Of greater extent than the preaural. It supports, along its free

edge, a row of feathers precisely similar to those on the opercular fold. They are over-

lapped by the feathers of the preaural fold. (PL 28. fig. 5.)

Ramal area not extending backwards as far as the angle of the jaw.

Inter ramal area. — Anteriorly, from the region at the level of the gape to the

symphysis of the mandibles, surrounded by an apterium, the posterior portion expanded

so as to merge with the ramal area.

Apt. colli laterale terminating at the base of the lower half of the circumaural fold,

and embracing the region of the angle of the mandible.

Pt. colli dorsalis. — Borne upon lateral folds, not closely investing the neck.

Pt. sjmialis (PL 26). — The arms of the interscapular fork, arising in the middle of

31*

250 MR. W. P. PTCRAFT ON THE

the intersca]iular region, very short, terminating a short distance from the free end of

the scaj)ula.

The arms of the lumhar fork represeated hy a single row of feathers arising over the

anterior end of the ilium and which, crossing over the free end of the scapula, terminate

on the axillary memhr'ane. The stem of this portion very distinct ; its free end is bifid,

and terminates some distance from the oil-gland.

Pt. ventralis. — Outer branch feebly developed, represented by a single row of feathers ;

median liranch broad, short, not extending beyond the middle of the sternum, the

recurved branch or " hook " very slender ; inner branch, arising in the middle region of

the furculum, follows the course of the clavicle and the carina, tlien turns inwards and

upwards to the thigh, whence it takes an almost straight course backwards to join its

fellow of the opposite side in front of the cloacal aperture.

Pt. femoralis. — Pemoro-crural band terminating at the knee-joint.

Pt. criiralis. — Feathers on the acrotarsium short. Planta bare. Acro[)odium covered

by numerous warty protuberances, each of which bears a degenerate feather ; little more

than the shaft, with perhaps — here and there — one or two rami, remaining ; radii absent.

Filoplumes absent. The base of the ungual j)halanx clothed with scales.

Pt. alaris : —

Bemiges. — No carpal diastema, the space between the metacarj)al and cubital

remiges being very much less than that separating the individual cubital remiges.

Tectrices -. —

T. mujores. — The major coverts on the dorsal sui'face gradually increasing in length

from 1-5. This last the longest ; 6th shorter than 5th.

T. mediae. — 1-5 gradually increasing in length, but the 5th abruptly longer than 1-4.

6th about as long as 4th. The 5th feather more closely bound to its covert — 5th major

covert — than the remaining feathers to their respective coverts.

T. minores (row no. 1). — Covert 5 abru2)tly long(>r than 1-4, but of the same length as 6.

Disproportion in the length of the coverts of this group, above the 1st row, less marked.

Mhmivphotheca. — Cere very short antero-posteriorly, much inflated, forming two

pisiform swellings on each side of the culmen. Aperture of the external naves circular,

dkected more forwards than outwards. Rhamphotheca compressed.

Podotheca. — Claws short, very little curved.

TJropygium. — Napiform.

Carine noctua, Scop.

Pt. capitis. — Fronto-parietal and occipital areas densely feathered.

Loreal area indistinct.

Interramal area expanded to join the ramal area on either side, from tlie level

of the gape backwards.

Apt. colli laterale terminating at the level of the posterior limb of the external

aperture of the ear.

Pi. colli dorsalis borne on a deep vertical fold ; no lateral folds.

MOEPHOLOGT OF THE OWLS. 251

Ft. spinalis with a short interscapular fork, the branches arising below the middle of

the interscapular region, short, widely divergent, tapering, terminating rather below the

free end of the scapula *. The stem of the posterior portion not forked, but running

sti-aight up to the convergent bases of the arms of the interscapular fork. Widest

posteriorly, forked terminally ; the branches short, not wide enough apart to embrace

the oil-gland.

Pt. colli veniralis. — Forks almost immediately after its origin.

Pt. centralis. — Outer branch very narrow ; median broad and strong, terminating in

the middle region of the sternum. The recurved branch (" hook ") very feeble. Inner

branch arises in the region of the middle of the furculum and runs in the dii'ection of

the carina of the sternum ; over the middle of the sternum it trends outwards and

upwards, again converging on the abdomen, each branch terminating separately some

distance in front of the free end of the pubis and not meeting its fellow in the middle

line in fi'ont of the cloacal aperture.

Pt. Immeralis. — Connected with the pt. veiitralis by a single row of feathers.

Pt.femoraUs. — Femoro-crural band terminating over the proximal third of the crus,

not running upwards to the femoro-tibial articulation.

Pt. cruralis. — Feathers of acrotarsium barely concealing the skin ; on acropodium

degenerate, shafts only remain. No filoplumes. Planta feathered ; the base of the

terminal phalanx of the toes covered by 3 scales.

Uliampotlieca. — Cere short, inflated, forming two pisiform swellings on either side of

the culmen as in Speotyto.

TIropygium. — Napiform, the tubular extremity relatively long.

Strix plammea, Linn.

Pteryla capitis :

Fr onto- parietal area. — In the form of a narrow, median tract of feathers,

bounded on either side by an apterium.

Occipital are a. — Occujoies the whole width of the skull, extending outwards on to

the postaural fold.

Loreal are a. — The base almost obliterated by a semioval apterium lying along the

margin of the tomium from the region of the nostril backwards to the gape. The inner

boundary of the apterium is formed by a single row of feathers running from the loreal

area backwards below the eye to join the feathers of the operculum.

C i r c u m a u r a 1 area (PI. 28. tig. 1, p. 229).— The preaural fold is well developed

and forms an operculum. It is clotlied by some I vows of delicate, elongated feathers,

having narrow, discontinuous vanes.

Postaural fold. — Its upper portion may be considered to merge into the upper

limb of the loreal area above the region of the middle of the eye; below it passes

insensibly into the ramal area (see " Periphery of the Disc," p. 252).

* 111 a young iudividual the interscapular termination of this tract was very narrow — out littlo wider than tie

stem. The branches were very short, and parallel, not divergent.

252 MR. W, p. PTCRAFT ON THE

Interramal are a. — The only specimen of a Barn Owl tvhicli I have been able

to procure I owe to the kindness of Dr. Sclater. Unfortunately it is so damaged in this

region that Mr. Meinertzbagen and I have been obliged to fall back upon Nitzsch's inter-

pretation and restore the figure after that given by him.

P e r i ph e r y o f t h e D i s c. — This is more sharply demarcated than in any other Owl so

far examined. The feathers taking part in its formation are seated in a deep fold of skin

which stands out abruptly from the general contoiir of the head in the form of a sharp

ridge. Its anterior portion is contribvited by the superior border of the loreal are;i ;

running backwards into the postaural fold, and downwards along the interior border of

the mandible, it finally dies out in the region corresponding to the level of the gape. The

feathers in the immediate region of the external aperture of the ear are very long, witb

narrow, discontinuous vanes, and all much curved forwards, so as to form a hollow around

the ear, and a very considerable lateral extension of the postaural fold.

Apt. colli lutcrale. — Terminating at the base of the jjostaural fold, some distance

below the level of the external aperture of the ear.

PL colli dorsalis. — Not borne upon lateral neck-folds, but closely investing the neck,

therein differing from all other Owls so far examined. It forms a diamond-shaped

expansion in the middle of the neck.

Tt. spinalis. — Interscapular fork arising within the interscapular region. Arms narrow,

3 rows of closely-packed feathers, not extending as far as the free end of the scapula.

The arms of the lumbar fork arise over the anterior end of the ilium, cross the free

end of tlie scapular, and terminate on the axillary membrane. The stem is truncated

posteriorly, terminating some distance in front of tlio oil-gland.

PL colli veiitralis. — Bifurcating on the lower \ of the neck, branches very narrow;

feathers set in oblique rows of 4 feathers in each row.

PL ventralis. — Outer branch moderately broad. Median branch narrow, not free

posteriorly, but continued backwards to join the inner branch over the region of the

posterior lateral process of the sternum. The "hook" is given off just before this

junction takes place. Inner branch very distinct ; coming off from the median opposite

a point corresponding with the region of the ventral \ of the furculum, it is continued

backwards to join its fellow of the opposite side over the free ends of the pubes.

PL alaris : —

Bemiges. — Metacarpo-digitals 11, cubitals 15, the innermost not readily distinguished

from their coverts.

Teetrices. — For i\\Q most part missing in this specimen.

Pt.femoralis. — Femoro-crural band terminating below the knee.

PL cniralis. — Feathers on the acrotarsium degenerate, the shaft only remaining. They

occur in groups of 3, of which ,the centre one, as described by Meijcre, is much the

longest; the two lateral shafts being in most cases minute, and sometimes absent. Each

group of 3 is seated under the anterior border of a soft, swollen scale. On the aero-

podium the scales become firmer and the feather-remnants fewer.

BliampJiotheca. — Cere closely investing the base of the beak, nostrils pierced in its

lower anterior border.

MORPHOLOGY 0¥ THE OWLS. 253

Podotheca. — Planta feathered, save the proximal end. The feathers on the posterior

border of the acrotarsium directed upwards. Scales oa the toes more distinct than on

the acrotarsium. Pectination of the claw of the middle toe very slightly developed.

IV. The Distribution of the Neossoptiles or Nestling-Down.

I hoped to liave been enabled to describe tbe nestling-down of Aslo, but after all failed

to procure a specimen of this genus. By the kindness, however, of my friend

Mr. Meiuertzliagen, a substitute has been provided in a nestling Speotijto cnnicularia,

which was one of a clutch of 5 bred in the Mottisfont aviaries this spring (1897).

There are two kinds of nestliug-dowu to be distinguished : (1) the down-feathers

■which precede the future definitive contour-feathers, and (2) those which precede the

future definitive down-feathers. This is a j)oint not to be overlooked, inasmuch as the

latter, as I have already shown in the case of Op'tsthocomus (14 a), may, from the

greater length and number of the rami, bear the greater share in clothing the young

bird.

Just as in Opistlwcomus, the nestling-plumage of tlie Common Kestrel, Falco tiiiimn-

culus, is mainly contributed by the down-feathers belonging to the second kind, the

down-tufts preceding the contour-feathers being relatively insignificant in size.

One might naturally expect to find that this two-fold down-clothing would obtain

wlierever coutoiu-- and down-feathers were to be found associated together in the adult.

This does not, however, appear to be the case, inasmuch as I find that the nestling-down

of the Common Duck, for instance, is entirely composed of the down-feathers of the first

order — those preceding the contour-feathers.

I would now suggest that these two kinds of nestling-down should in future be

carefully distinguished when describing the plumage of nestling-birds. The feathers

preceding the contour-feathers might be called pre-ioenncB, whilst those preceding the

future definitive down-feathers might be called pi^e-plumulte.

In the nestling of Speotyto the feathers investing the trunk are pre-pennae ; pre-plumulae

are absent. As is shown elsewhere, the corresponding plumulse are absent on the trunk

of the adult also. The clothing of the wing differs from that of the trunk in that pre-

plumulse occur amongst the pre-penna?, hui they are very small and contribute no great

part towards the general covering. Whether these last are really pre-plimiulae or the

actual definitive down-feathers I am unable to decide. Tlie question can be settled only

by the examination of younger specimens, the one under consideration being half-tledged.

Save the remiges and their dorsal major coverts, and the rectrices, the true contour-

featliers of the adult do not seem to be devc-loped till after the first moult. All the

nestlings which I have been enabled to examine — ranging up to birds nearly full-grown —

have been clothed with a peculiar loose semiplumous covering, sprinkled here and there,

in some cases, with typical adult contour-feathers.

254

MR. W. P. PTCEAFT ON THE

V. Ptertlosis or the Embeyo.

Asio OTTJS, Linn.

My embryos of this species may be divided into 3 stages, tbe last corresponding to

that of a 10-day chick. In this, only the rudiments of the contour-feathers have made

their appearance in the form of the characteristic bead-like papillae.

Rio'ht side view of an embryo of Asio oins, showing the form of the pterylse. At this stage the pteryla colli

dorsalis closely invests the neck as in Sirix Jimnmea. The external aperture of the ear has not yet

reached its full size, and there are no pre- and postaural folds. The beak has not yet assumed its

characteristic curved shape.

Stage III.

FterylcB : —

Ft. ccqdtis. — The feathei'ing of the upper part of the head, as indicated by the

feather-rudiments, is very uniform, giving no sign of the differentiation into areas —

loreal, fronto-parietal, &c.— which appear in the adult.

I n t e r r a m a 1 area as in the adult.

Ft. colli dorsalis. — There are no lateral folds, the skin closely investing the neck, as

in StrLv Jlammea.

Ft. spinalis as in adult.

Ft. ventralis. — No outer branch is yet visible.

Ft.femoralis. — As in adult, femoro-crural band strongly marked.

Ft. cruralis. — No feather-rudiments have yet made their appearance on the podotheca.

Ft. alaris. — The position of the future remiges, and nearly all the tectrices, are now

indicated, and the wing is seen to be aquintocubital.

The external aperture of the ear has not yet reached its full development. There are

no opercular or postaural folds.

Bhamphotheca. — Note the straight form of the beak and the absence of any indication

of a " cere."

MOEPHOLOGY OF THE OWLS. 255

Clmos. — There is a small claw on the pollex ; there is also an indication of a claw in

Digit II.

Stage II.

Pt. coj^ntis. — Only the feathers of the loreal area and the region about the eye yet

indicated. The position of the trunk-feathers is almost as plainly indicated as in

Stage III. In the pteryla alaris, however, only the remiges and dorsal major coverts

are yet suggested.

Stage I.

The skin as yet perfectly smooth.

Carine brama, Temm.*

This embryo almost exactly corresponds to Stage III. of Asio accipitrUms.

Pterylte : —

Pf. capitis. — ^The feathering of the upper -part of the head not differentiated into

distinct areas.

I n t e r r a m a 1 are a. — Expanding cit the level of the gape to join the ramal area.

Pf. spinalis. — The interscapular fork differs markedly from that of C. noctua (p. 250),

in that there are well-marked interscaj)ular branches present as in Asio, Scops, &c. ; they

terminate over the region of the free end of the scapula. In the adult mentioned the

interscapular fork is barely perceptible.

There is a well-marked lumbar fork, the branches of which arise near the anterior

border of the ilium, are widely divergent, and extend on to the axillary membrane. In

this also this species differs from the adult C. noctua, in which there is no lumbar fork.

Pf. femoralis. — Pemoro-crural band terminates at knee-joint.

Both digits, I. and II., of the wing are furnished with claws.

Nyctala Tengmalmi, Gm.

Stage IV. — Ai*eas of feather-distribution as in the adult. There is a claw on both

poUex and index digits. Tlie external aperture of the ear is oval in form ; its vertical

axis is nearly twice that of the longitudinal axis of the closed eyelid ; it is entirely closed

by the sclerotic ring, which comes quite to the surface.

Stage III. — The form of the interramal tract can can be weU studied here. It is

very broad on the throat, and narrows suddenly on the upper part of the neck.

Pt. spinalis. — The lumbar stem appears to be continued forwards, in the form of two

single parallel rows of feathers, to join the free ends of the interscapular branches. It

is cleft in front of the oU-glaud.

Stage II. — The papillsje are just appearing ; their distribution appears to be the same

as in Staa;e III.

^o^

Strix flammea, Linn.

The embryos of this species represent Stages III. to V. That corresponding to

Stage III. is most instructive, and best preserved ; and from this the following description

is taken, the remaining stages being compared with this.

* For this most beautifully-preserved specimen I have to thank my friend Mr. .Jesse of Lucknow.

SECOIsD series. — ZOOLOGY, VOL. VII. 35

256 ME. W. P. PTCRAFT ON THE

FterylfB : —

Pt. cajyft/s. — The papillne which will give rise to the peripheral disc-feathers are fairly

sharply defined from the rest of those covering the head, as a narrow baud of closely-set

raised points. The aperture of the ear is nearly circular ; its vertical axis is less than

that of the longitudinal axis of the closed eyelid. There is no trace of an operculum.

Ft. spinalis. — Interscapular fork with the branches very long, and joining those of

the lumbar fork so as to enclose a space. At the junction of the free ends of the lumbar

fork with those of the interscapular fork, a side branch is given off from each to the

posterior end of the Pt. humeralis.

Stages IV. and V. agree, so far as the distribution of the feathers is concerned, with

Stage III. In Stage V. the first trace of the operculum appears.

VI. Structure op the Feathers.

Contour-feathers. — These, in the Ow^ls, are of considerable length, and soft and some-

what loose in texture. There is no aftershaft. The remiges in many, e. g. Asio, Bubo,

present on the upper surface of the vexillum a very characteristic velvety pile, due to

the enormous elongation of the free ends of the distal radii, which extend forw^ards over

as many as three rami, not including the ramus from which they arise.

The feathers composing the facial disc present a few points w^orthy of notice. Round

the free edge of the operculum they have an elongated and rigid shaft, bearing

numerous moderately long rami, which form a discontinuous vexillum. The most distal

rami break up into about three short branches, all of which bear fila, thus giving the tips

■ — under the microscope — a curiously frayed appearance. The radii are very short, set

almost parallel with the ramus, and showing no more than traces of fila. They also

occur on the shaft in the internodes between the bases of the rami.

A feather from the lower limb of the postaural fold shows the following points : —

The shaft is bent upon the calamus at a considerable angle in an upward and lateral

direction. The calamus is abruptly distinguishable from the scapus by its greater

thickness. The inner vexillum is roughly triangular in form, the base extending from

the superior umbilicus to the top of the stem ; the outer vexillum is much smaller and

also triangular, its base running from the upper umbilicus to the middle of the stem.

The rami are entirely disconnected and wadely separated. The radii are very short ; those

of the proximal series lie parallel with the ramus ; the distal radii are longer. Fila are

absent. Short radii run along the scapus in the interval between the rami.

The feathers of the Loreal area are long, with fairly stiff, rigid axes. Rami

very short, degenerate, showing neither fila nor booklets, and decreasing in length on

each side of the ramus from the base upw'ai'ds, finally disappearing. They also run

along the internodes on each side of the shaft from the base of one ramus to that of the

next in front.

Plmmilce. — In these the rhachis is relatively short as compared with the rami, which

are of great length. The radii are long, transparent, and divisible into segments —

nodes and internodes — by the deposition of pigment in the region of the fila. The fila

MOEPHOLOGY OF THE OWLS.

257

occur in pairs (fig. 3, G) at the proximal nodes ; beyond this thej^ suddenly disappear, but

the corresponding" region is marked by a gentle swelling containing a dark pigment,

which in masses appears black.

The adult down-feathers of Asio, Speotyto, and otlier Owls closely resemble those of

the Kestrel {Falco t'mmmculm, fig. 3, E) ; but they may be distinguished by the

following points : — In the latter the nodal areas of tlie radii are more numerous, the

Fig. 3.

B

--^rr/^^- 1.. -'W- - J»iTf??r?r??

^^^^^m^ ^^^ — -—

A, portion of a rndius from a defini-

tive down -feather of Capri-

multjus eurupa'us. The swelling

of the nodes is somewhat ex-

aggerated in the figure. B, por-

tion of a radius of a pre-peniia

of C. e.uropcms. C, portion of

a radius from a pre-plumula of

Falco tiiinunculus. D, portion

of a radius from a pre-penna,

and E, portion of a radius from

a definitive plumule of F. tin-

nuncxlus. F, portion of a radius

from a pre-penna, and G, por-

tion of a radius from a definitive

plumule of Spxotyto cunicularia.

f, filum.

,/

rhachis is much longer, and there is a vestigial aftershaft. They may be very readily

distinguished from those of Caprimulrjus (fig. 3, A) by the greater length of the radii in

the latter, the long black nodes — longer than the internodes and very little thicker, — and

the absence of fila. Like the Kestrel, the down-feathers of Caprimulgus possess a long

rhachis and a vestigial aftershaft.

Filophmies. — In the adult these present no special features of interest. The rhachis

is long, bearing from two to three rami (fig. 4). The radii are of moderate length,

and bear, here and there, a few fila. The only case in which I failed to find filoplumes

in the adtdt was that of Speotyto cunicularia.

35*

258

ME. W. P. PTCEAFT ON THE

In the nestling, however, they were readily visible in the form of somewhat

conspicuous packets, one at the base of every contour-feather. Their examination under

the microscope revealed some very interesting facts concerning the nature and history

of these curiously modified feathers. As will be seen in fig. 5, each at this stage

consists of a sheath investing a number of rami, and a rhachis, clustered around a column

of " pith-" cells. Before the full growth of the feather is attained everything save the

Fis. 4.

Fig. 5.

Fig. 4. — The distal end of a filojjlume of jS'co^js leucotis.

Fig. 5.-Filoplume of a nestling Siuotuto mnicularia. The part marked / is all that remains in the adult, and

forms the filoplume ; T, the transitory radii ; j*, pith-cells.

main axis is thrown off. This remains as the typical filopkune of the adult. Dr. Gadow

(4} remarks, "their development shows them to he degenerate, and not primitive

feathers."

Neossoptiles.—Ks is pointed out in another part of this paper (p. 253), two kinds of

neossoptiles must be distinguished — (1) pre-pennse and (2) pre-plumulae.

Pre-penn£e * can be readily distinguished from pre-plumulce only under the microscope.

The component rami of these umbelliform down-tufts, being continuous with those of

the definitive contour-feathers, are broken up and spread out horizontally as soon as

the tips of these latter have burst through the sheath by which they were enclosed.

* The pre-pcnna3 described arc those of Sptotyto mniculana.

MOEPHOLOaT OF THE OWLS. 259

The radii — like the rami — are transparent. Fila are generally but not always present.

The rami are laterally compressed. Structurally they can scarcely be distinguished from

those of Falco tinnunculus ; but in this latter the fila are longest and regularly arranged

along the radius (fig. 3, D).

The pre-pennse of Capriniulgm can readily be distinguished from either Speotyto or

Falco tinminculus. As in these, they are umbelliform, but the rami are produced con-

siderably beyond the most distal radii into long filamentous processes, and the radii bear

minute fila at regular intervals (fig. 3, B).

The pre-plunuda; differ from the pre-pennae, both in Speotyto and the Kestrel, in that

the radii are divided np into segments by the collection of pigment in the region from

which the fila arise. In this respect they resemble the definitive down-feathers, but can

always be distinguished from them. At least this is true of the Kestrel. Thus, in this

species, the pigment, though in the form of a dense black deposit in the region of the

fila, shows a tendency to be distributed all along the radius (fig. 3, C). Eurther, the

pre-plumulse are umljelliform, whilst the definitive plumulae have a rhachis and after-

shaft. From the fact that the feathers which I have doubtfully described as pre-

plumulae in Speotyto have a distinct rhachis, and the radii are indistinguishable from

those of the adult, it is more than probable that these feathers are really definitive

down-feathers.

Both the pre-plumula3 and the definitive down-feathers of Speotyto — if these, in this

case, are not one and the same — can be distinguished from the plumulae of the Kestrel in

that, in the latter, the segments of the radius are more numerous (fig. 3, E) and the

rhachis is longer and supports an aftershaft.

VII. The External Ear. (Plates 27-28).

The external aperture of the ear of birds is usually concealed by feathers. If these

be raised, a small round or oval opening will be seen leading into a more or less spacious

chamber — the outer portion of the auditory meatus. This chamber is continued inwards

in the form of a tunnel to the tympanum — the boundary-Avall between it and the middle

e;ir. It will be helpful, for clearness' sake, in the present paper to call the cavern-like

chamber communicating directly with the outer world the Cavernum, and the tubular

inner continuation the Cavornulum.

In Athene noctua we have apparently one of the least specialized meatuses of all the Owls.

The external opening is almost circular in form and very small, its vertical axis being

about half the height of the horizontal axis of the closed eyelid. The cavernum is

spacious, and leads backwards and downwards to pass by insensible gradations to the

cavernulum. In other words, it represents the typicalimspecialized form of the external

ear in birds. Erom this ue can pass by a series of slight gradations to forms of con-

siderable relative complexity, as will presently be shown.

"What has been described for Athene will answer almost equally well for Speotyto.

Bubo lacteus leads us a step further ; at the same time it represents the simplest

form of the external ear to be found in the whole genus save that of B. nycteus. The

260 ME. W. P. PYCEAFT ON THE

aperture is almost circular ; its vertical axis is rather less than the horizontal axis of

the eyehd. The cavernuui gradually deepens from aliove downwards and backwards.

Its floor is divided into two deep pits by a vertical fold of skin investing the second

portion of the temporalis muscle which runs from the postorhital process to the

corouoid region of the lower jaw.

In Bubo nycteus the external aperture is pyriform in shape, the base being directed

upwards and sloping oliliquely back^vards ; its vertical axis is equal to the horizontal axis

of the eyelid. The cavernuDi is sjjacious, and closely I'esembles that of B. macnlosits.

It differs, however, in this respect, that the eye projects more laterally, and has given rise

to a shallow depression immediately behind it, at the bottom of which lies the mouth of

the cavernulum.

In Bubo ignavus the aperture is oval, its vertical axis equal to the horizontal axis of

the eyelid. The depression beliind the eye just described is here much more marked, so

that the cavernum is divisible into an anterior and a posterior portion. It is further-

more continued upwards between the skin and the skull to the crown of the head, and

backwards between the postaui'al fold and the skull : thus it has gained a considerable

increase in size.

B. virginianiis differs from B- ignavus in that the aperture is somewdiat smaller, and

the anterior and posterior divisions of the cavernum still more sharply marked.

B. maculosus agrees with B. ignavus in the' size of the aperture, but differs from this

species and agrees with B. vlrgiuianus in that the cavernum is divisible into two portions,

the posterior division being even deeper than in this species.

Bubo torqimhis agrees with B. virginiaims in the size of the aperture, but more nearly

approaches B. muculosus in the form and size of the cavernum.

Scops and Bubo appear to closely resemble one another in the form of the external

ear, so far as can be judged from an examination of two species of the former genus.

The posterior division ditfers from that of Bubo in that it extends the whole vertical

heirfit of the cavernum instead of being confined to its lower third.

In S. leucotis the aperture is semilunar, and its vertical axis is equal to the horizontal

axis of the eyelid. There is a considerable extension of the cavernum iipwards to the

crown of the head, between the skull and the skin, and between the postaural fold and

the skull.

In S. giu the vertical axis of the aperture is only half the horizontal axis of the eyelid.

The anterior portion of the cavernum is very shallow, being almost filled by the eye.

The transition between the anterior and posterior portions is sudden, aud the latter

very deep. The floor is spacious.

Ninox noccs-zealandice has an almost circular aperture, the vertical axis of which is

nearly equal to the horizontal axis of the eyelid. The cavernum closely resembles that

of Scops.

In Sceloglau.i: albifacles, so far as I could make out from a relaxed skin (p. 244). the

aperture of the ear was semilunar, equal to, and probably greater than, the horizontal

axis of tIic eyelid, iiazardiug a guess, I should say that the cavernum probably most

closely resembled that of Bubo. Mr. J. H. Gurney (7), after the examination of a

MOEPHOLO&T or THE OWLS. 261

specimen soon after death, gives the measurements of the external aperture as i~2 inch,

and describes it as of an elongated shape. " The ears," he writes, " are very low in the

head, in fact placed beneath the eyes, and appear, from external examination, to be quite

symmetrical ; but after the bird was skinned I could see, by looking at the skull from

the back, that the hind angle of the inferior mandible was lower on one side than the

other."

Sijrnia ulula has a nearly circular apertnx'e, the vertical axis of wliich is equal to

the horizontal axis of the eyelid. The cavernum is spacious, divisible into anterior

and posterior portions, sharply defined ; the latter very deep, and passing insensibly into

the cavernulum. There is a considerable upward extension of the cavernum between

the skin and skull as far as the crown of the head.

So far we have been discussing forms of the external ear which are perfectly

symmeti"ical on the two sides of the head. In the forms presently to be described

there is a marked asymmetry, with exceptions, however, which will be noticed in their

place.

The first and most remarkable of these is that of Nyctala Tencjmalmi. The mem-

branous aperture is oval in form ; its vertical axis is twice the length of the longitudinal

axis of the eyelid. The preaural fold — the loose flap of membrane formino- the

anterior border of the apertm-e — forms an imperfect operculum (PL 27. figs. 5-6).

The cavernum, as in the forms just described, is divisible into an anterior and a posterior

portion, the latter being in this case by far the larger. By a considerable devcloijment

of the lateral wing of the squamosal and exoccipital bones, the form of the meatus

has been considerably modified, and is, as just hinted, asymmetrical on the two sides of

the head.

On the left side this wing takes the form of a thin bony plate jutting out from the wall

of the cranium from behind, outwards, downwards, and forwards to the level of the post-

orbital process, so as to form a complete bony outer wall to the posterior portion of the

cavernum. It is continued downwards and forwards to overlap the articulation of the

lower jaw.

The bony floor of the cavernum is incomplete, being hollowed out or " cut away "

to expose the quadrate from behind. Thus the posterior portion is converted into a

deep recess roofed over by bone, and looking outwards and forwards on the anterior

portion.

On the right side the squamosal Ming does not extend along the cranium as far forwards

as the base of the postorbital process, but trends outwards and forwards to join the

outer border of its lower end, instead of being continued downwards to overhang the

articulation of the jaw as on the left side.

Thus the posterior diAasion of the cavernum is converted into a deep recess, differing

from that of the left side in that it is open above and that it is shut oiT below from the

outer world and from a portion of itself by the junction of the squamosal wing with the

postorbital process. The portion cut off, just referred to, is represented by the deep

hollow over the superior border of the articular end of the jaw, and is well shown in

fig. 6, PL 27.

262 ME. W. P. PTCEAFT ON THE

In Asia the asymmetry does not extend to the bones of the skull, hut is confined to

certain membranes uithin the cavernum.

In A. accipitrinus (PI. 27. figs. 3— i) the membranous aperture is crescentic in form and

of great size, extending from the middle of the lower jaw, from a point corresponding

to a line drawn from the base of the cere downwards, backwards, and upw^ards to a point

over the region of the middle of the eye. Thus the cavernum has gained an enormous

superficial area, such as has been liinted at in other Owls, in the extension of the

cavernum over the skull, and backAvards round to tlie occiput. The pre- and postaural

folds are very A'olumincnis, the former being kno\\Ti as the opercidum.

That portion of the cavernum which lodges the eye, and the cavity behind, corresponds

to the anterior and posterior divisions of the cavernum in other species. The latter

division is here much increased, and, by reason of the disposition of certain membranes,

has come to be asymmetrical as regards the two sides of the head.

On the right side this will be seen to be divided into an upper and a lower chamber by

means of a membranous horizontal partition running from the squamosal wing to the

eye, and forward to the operculum. The upper chamber is blind, and may therefore be

called the diverticulum. It is possible that it may act as a sort of resonator. The lower,

which should, I would suggest, be called the via recta, is very spacious and leads to the

caverntdum. It is bounded above by the floor of the diverticulum; behind by the

squamosal wing ; below by a thin membrane from the postaural fold to the operculum,

running immediately above the superior border of the lower jaw ; and in front by a thin

membrane from the lower jaw to a bony tul^ercle on the postorbital process.

On the left the diverticulum lies below the via recta. The membrane dividing the

two is placed nearer the lower jaw, and sloj^es oljliquely downwards and inwards. It is

also partly attached to the tubercle of the postorbital process just referred to — which

tubercle, by the way, occurs o)ily in this species.

The ear of ^. otus differs from the species just described in that there is no postorbital

tubercle, that the via recta of the left side is without the anterior boundary-membrane,

and in that the diverticulum of the cavernum is narrow and deep instead of broad and

shallow.

Syridmn furnishes iis with a third type of modification of the external ear.

In .S. aluco it is asymmetrical, but the asjTnmetry is confined to the membranous

aperture, which is semilunar in form. The vertical axis of the aperture of the right side

is equal to the horizontal axis of the eyelid ; that of the left aperture is less.

The cavernum is divisible into anterior and posterior portions, the former larger and

shallow'er, the latter deep, but confined to the lower half of the posterior corner of the

cavernum, the floor of which is fairly spacious. The upward continuation of the

cavernum over the skull is but slight. The pre- and postaural folds are large, the

former, constituting the operculum, overlapping the free edge of the postaiu-al fold wdien

the ear is closed.

S. uralense is generally believed to be asymmetrical as regards the form of the

external ear, and, moreover, the asymmetry is further supposed to extend to the bones of

the skull. A specimen in the flesh from my late friend Mr. Meinertzhagen's aviaries

MORPHOLOGY OF THE OWLS. 268

certainly does not contirm these beliefs — at least so far as the soft parts are concerned ;

which differed from those of S. ahtco only in that the vertical axis of the aperture was

slightly greater than the longitudinal axis of the eye, and that there was no asymmetry,

the size of the aperture being the same on each side of the head.

Strix Jlammea concludes the list of those which 1 have been enabled to examine. The,

aperture of the ear is almost square ; its vertical axis is equal to half the longitudinal

axis of the eyelid. The preaural fold constitutes an operculum.

The cavernum is not divisible into anterior and posterior divisions, but forms a deep

cavity leading almost directly into the caverntdum.

The operculum, arising a short distance behind the gape as a low ridge, rapidly expands

into a square flap terminating some distance above the free edge of the aperture on a level

with the top of the eye. The base of the operculum measures about twice the length of

the aperture of the ear.

The loose membranous postaural fold supporting the peripheral disc-feathers of Asio

otus is here represented by a low dermal ridge standing up distinctly from the surface

of the head. It arises on the inferior border of the lower jaw, and running backwards,

upwards, and forwards, terminates at the base of the beak. This ridge, as previously

intimated, serves to support the peripheral disc-feathers. These are much elongated, and

narrow-vaned, standing out at right angles to the head, and curved so as to present

a deeply concave surface forwards, and a corresponding convex sru'face looking backwards.

From their shaj)e and disjjosition these feathers afford an admirable apparatus for the

collection of sound.

It is not surprising to find that the operculum varies slightly in form. In one specimen

(of two examined) the lateral border was shorter than that described above ; and in

consequence the superior border slopes gently upwards, giving the operculum a truncated-

conical rather tlian a square outline.

It would seem, from these facts, that the form of the external ear was at some time

subject to considerable variations, the most successful of which have become more or less

fixed by selection.

Results.

That a detailed study of the Pterylography of the Owls would lead to any very startling

results was hardly to be expected, and, as the " Keys " at the end of this paper show, it

does little more than confirm wliat has alreadv been done. It must not be forErotten,

however, that these results have been obtained by a deliberate desertion of the beaten

track into the neglected highways and byways opened up by Nitzsch, but sinc<^ allowed

to sink almost into oblivion.

I have been enabled to push Nitzsch's methods somewhat further than lie himself

attempted, for it will be remembered that he founded his genera rather upon the data

obtainable by the time-honoured methods of measurements and the relative proportions

in the length of the remiges, their number and general outline, and so on, rather than

upon pterylological characters, which seemed to him to differ little, if at all, from his

type Bubo.

SECOND SERIES. — ZOOLOGY, VOL. VII. 3(1

264 .MR. AV. P. PYCEAFT ON THE

That the common resemhlances which pervade the whole group are many, no one mil

deny, but that nevertheless every species possesses some slight departure of its own from

the main tyj)e, which, judiciously combined with other external characters, such as the

form of the external ear and of the cere, will absolutely distinguish it from every other,

is a fact which T believe I have been the first to point out ; it now awaits the test of

criticism from other quarters.

On the strength of the evidence brought to light during the coarse of the present

investigation, I have felt justified in removing certai" genera from their moss-grown

pedestals and placing them elsewhere, or even suppressing their claims to generic rank

altogether. Sometimes this has been but an act of restoration, sometimes of innovation.

This spiriting away of genera has led to the complete isolation of forms generally closely

associated : thus, Asio, Syrninm, and Nyctala have been regarded as closely allied by such

authorities as Prof. Newton, Dr. Sharjje, and Mr. Ridgway for instance, on the strength

of the possession of an operculum and the size of the external aperture of the ear ;

nevertheless, I ventixre to think that this relationship is only apparent.

The genus Syrnium of Dr. Sharpe's Catalogue, again, probably includes several species

which will have to be similarly separated. I infer this from the fact that his Syrnium

2iers2ncillatum — the Bubo torqnahis of the present paper — belongs undoubtedly to the

genus Bubo, since, apart from the absence of an operculum and the small size of the

external aperture of the ear, its pterylosis alone shows it to be much more closely allied

to this genus than to Syrimmi.

The real position of Sceloglaux and Ninox has proved a bard nut to crack, the former

especially so. In its general pterolysis it closely resembles Bubo, in the form of the

cere and external aperture of the ear it resembles Scops, while it differs from both these

genera in the great width of the lumbar division of the spinal tract ; but whether on this

account it is entitled to generic rank is open to question. Certain points in the osteology

of the skull — to be discussed in my next paper — would have inclined me to place it in

the Nyctalincc ; and it remains to be-seen whether, when the rest of its anatomy has been

worked out, these suspicions will be confirmed.

Bubo nycteus, again, has proved rather a stumbling-block. Is this, or is it not,

\\ orthy of generic rank ?

To jilace Carine and Speotyto in the same genvis would, I fear, rouse some adverse

criticism. I am sorry, but at present this seems necessary. After I have completed my

study of the two forms it is jiossible that I shall find that, after all, they are worthy of

separate generic rank.

The skull and the aperture of the ear of Syrnium, uralense and S. lapponicum are generally

described as asymmetrical. Whatever may be the case in the latter sj)ecies, in the

former this region is most certainly symmetrical, as is proved by a specimen in the flesh

generously furnished me by my much-lamented friend Mr. Meinertzhagen. I have

besides a skull of this species kindly lent to me by Prof. Newton, which is also quite

symmetrical.

That the nestling-down of ptilopsedic birds may consist of two distinct kinds of feathers

is a point of some interest, and which may yield some useful facts if carefully

MOEPHOLOGY OF THE OWLS. 265

studied. It is probable, as I liave pointed out in an eaiiier part of this paper, that

" pre-pennae " only are present in the young Owl, and that the " pre-plumulge " are not

represented in the very young nestling. When one reflects on the gi-eat range of grada-

tion in complexity of structure that obtains in the pre-pennae of different groups, from

the highly complex featliers of the Tinairiou, through the less complex feathers of the

GalIiform.es and Anserufonnes to the exceedingly simple hair-like structures of tlie

Columhce, it is pretty obvious that a great deal of work yet remains to be done before

this study is exhausted.

JS'itzsch was apjoarently the first to notice the twofold nature of the neossoptiles. He

wrote concerning the " nest-plumage of Diurnal Raptorial Birds " that it " consists as

usual of downy barbs which are attached to the first perfect barbs of all the contour •

feathers, even the remigcs and rectrices, and disappear as the bird becomes fledged .

Moreover, the whole body, with tlie exception of the axillary cavity and lateral neck-

spaces, is covered with true permanent down-feathers, which bear no evanescent tips.'

In this last point, that the absence of " evanescent tips " to the feathers in question

proved them to be permanent down-feathers, he is evidently mistaken, inasmuch as they

are quite distinguishable from the defioitiv(; down-feathers, as was pointed out in the

earlier part of this paper.

Dr. Gadow has stated that down-feathers occur on the nestling wherever they are

found on the adult. This is certainly not the case in the Common Duck, and there are

probably mauy other exceptions.

The position of the femoro-crural band, which is peculiarly well developed in the

Owls, if it is not confined to this group, was a point upon which I was for a time inclined

to place considerable hope, and even yet it may prove of no little value to the often hard-

pressed taxonomist. For the moment, however, with me its trustworthiness is under

a cloud. The point, it must be remarked, is to note whether its outer end terminates

above or below the knee. After examining a considerable number of spirit-specimens

with regard to this point, an uncomfortable suspicion crossed me tliat this might dej)end

upon the position of the legs when finally fixed by the liardening influence of the spirit :

that is to say, it may depend upon the amount of rotation of the femur towards the

spine, since the skin in this region seems to have a certain amount of " play," in Avhich

case, of course, this band might appear to terminate a little above or a little below the

knee, just as this was near to or far from the vertebral column. Certainly the rather

large series of Asio accipltrinus all agree in having this band terminate at the knee-

joint ; in Bubo it appears to terminate below the knee, and in Carine very much below

this region. It was over this very species, however, that my faith received its first

shock, inasmuch as in a second example of C. noctua, which I examined before placing

it in spii'it, i was able to move the distal end of this tract slightly up or down at will.

The amount was slight, but still appreciable ; of course my test may be at fault, as I

pushed the leg upwards and the skin downwards at the same time. Now this particular

specimen had been dead some days, so tliat the delicate attachments may a'l have broken

away directly my somewhat rough experiment was begun; it is to be hoped that someone

will try to settle this point soon.

36*

266 MR. W. p. PYCRAFT ON THE

A comparison between the pterylosis of the adult and the embryo could not be expected

to lead to any very startling contrasts ; nor does it. It is interesting to notice, however,

that in none of the embryos of Jsio which I have examined is there any trace of the

voluminous neck-folds of the adult, but tlie feather-rudiments are seen to closely invest

the neck, as in Strix Jlannnea. Again, the external aperture of the ear in this species is

marked by a shallow depression whose long axis is not more than twice that of the

longitudinal axis of the eyelid ; the opercular and postaural folds are not even hinted at.

In Strix flammea the operculum, as in Asio, does not appear till later in development ;

its peculiar four-sided form seems not to be assumed until after the development

of this fold.

The branches of the interscapular fork in the embryo of Strix appear to be longer

than in the adult ; but since I have only had the opportunity of examining a single adult

specimen, little importance can be attached to this. Similarly the interscapular fork of

Carine hrama differed, and this time markedly, from what one would have expected,

inasmuch as its branches were of considerable length, and not, as in the adult of C. noctua,

short and barely perceptible. This may mean one of three things : (1) the embryo is not

that of C. brama ; (2) that C. hrama may not belong to the genus Carine, but some other

genus of the Btihonidcc ; or (3) that this may represent an earlier stage in the history of

the development of this region of the tract.

In all the embryos there was a distinct claw both on the pollex and index digits. The

form of the beak in all the embryos agreed with that of the embryo and adult of Strix in

being relatively long and straight, and contrasted with the short curved beak of the

embryo of Falco or of the adult Owls of the Asionid group.

We come now to a question of wider and therefore of more general interest — the

nature of the evidence that a study of the Pterylography of the Owls affords as to their

systematic position.

Nitzsch (13) years ago, approaching the subject from this point of view, came to the

conclusion that they were most nearly related to the Accipitres. They formed his

Aecipitrin(B nocturnce. He tells us that " there are two points which essentially distin-

guish this group pterylogra])hically from the preceding (Accijritres dkirnce), namely, the

constant absence of the aftershaft and the tcant of the circlet of feathers at the apex of

the oil-gland.'" And, further, " In their form the tracts agree in general with those of

the Ealcons, although they present noticeable differences. Among these the chief is that

in the Owls the region of the throat betAveen the rami of the lower mandible is never

continuously feathered, but the inferior tract issues from the angle of the gonys in the

form of a narrow band, and divides on the middle of the neck or close to the front of the

furcula " The ^;/?<?r//^rt»mfr«^zs agreed, he found, very closely with that of C/rCM«.

The pt. spinalis, " although arranged in accordance with the principal type of the Ealcons,

presents this difference — the two arms of the dorsal portion which run to the fork of the

scapular portion consist, pi-obably ahvays, of two rows of feathers."

As the present paper show^s, his description of the interi'amal area must be taken as

the exception, not the rule. Por the rest, one may adopt the auditor's formula, save in

one or two minor details — " examined and found correct."

MOEPHOLOGY OF THE OWLS, 267

Garrod (5) tackled this question after an examination of the pterylosis of Steatornis,

which he compares with the Owls on the one hand and the Caprimulgkl(B on the other.

Judging from internal evidence, I should say that it is prol)ahle that his information

concerning the two latter groups Avas gleaned from Nitzsch rather than at first hand.

This latter author, by the way, it will be remembered, noticed that in his Caprimulgi

" the forms of the tracts, singularly enough, have a remarkable resemblance to the type

of several Rapacious Birds, but differs in tlie various genera. Among these analogies I

reckon the forking and interruption of the spinal tract between the shoulder-blades in

Caprimiilgus, the emission of an interior branch from the end of the gular portion of

the inferior tract in Nyctornis, and the division of the dorsal and rump portions of the

spinal tract in the same genus." And in describing the pleryla ventraUs of Nyctornis

he writes : — " Inferior tract divided from the throat, emitting a narrow cu.rved inner

branch which extends ujion the breast at the lower extremity of the neck. Behind this

branch it is so diminished that it becomes nearly interrupted, as in Gypaetos, to the

inferior tract of which it has a great resemblance In this bird also a hook

originates from the end of the jjectoral band and runs to the hy^wpteron."

Thus it is evident that Nitzsch regarded the similarity in the disposition of the tracts

in certain Cuprinmlgi and certain "Rapacious Birds" as an interesting coincidence

rather than proof of affinity. Moreover, he dwells rather upon the similarity between

this group and the Accipitres proper than between this group and the Owls.

To resume : Garrod, after describing the pterylosis of Steatornis — which, except for

the spinal tract, agrees apparently pretty much with Caprlmulgus — concludes that " the

above-described pterylosis clearly indicates tliat in the arrangement of its feathers Steat-

ornis more closely resembles the Strigidcs than the Caprimidgidce, though it differs

considerably from both. It resembles the Strigidce and differs from the Caprimulgida

in having no aftershaft to the contour-feathers *, in not having the occipital tract divided

up into narrow longitudinal rows, in having spaces on eacli side of the submaxillary

tract, in having the pectoral portion of the inferior tract in two parts, of which the inner

approaches the carina sterni above and separates from it as it descends, in having the

upper wing-surface uniformly feathered, and in having a large infuudibuliform oil-gland.

In none of the Caprimulgidce does the inferior tract continue simple down the neck,

whilst in Strix jiammea, as in Steatornis, it does not bifurcate till in tlie region of the

furcula. But Steatornis resembles the Caprinmlgidcc and differs from the Strigidce in

having ten rectrices ; it differs from both, however, in that the inferior portion of the

dorsal tract does not unite at all with the scapular fork of the superior portion, in

having the outer Ijranch of the pectoral tract diffused and descending far over the

abdomen, and in the general tendency to the scattering of the feathers."

Of the points in which Steatornis is supposed to resemble the Owls the most important

are the second and fourth, but in this last tlie resemblance is not very close. As

Garrod points out, Steatornis differs considerably from both Striges and Caprimulgi.

Further evidence on the question has yet to be tqiken, which is that of the microscopical

* Dr. Gadow has poiutfd out (3) that in this Garrod was mistaken ; the aftershaft is of considerable size.

268 -ME. W. P. PYCRAFT ON THE

strxicture of the nestling-down and definitive down-feathers, and to my mind this will

have greater weight than such points as the absence of an aftersliaft or in the occipitnl

tract not being divided up into "narrow longitudinal rows." And it will further

outweigh the very slight resemblance whicli may be traced in the pt. ventralis. and over-

come what is at present a bar, serving to isolate it from either of the two groups in

question — the peculiar form of the lumbar region of the p^. spinalis. Garrod's verdict,

that " In its pterylosis Steatori/is resembles the Strigidte much * more than any of

the allied families," is, I think, rather an ovei*-estimation of the facts at present at our

disposal.

With Dr. Gadow's evidence (3) the case for the systematic position of the Owls from

the standpoint of pterylosis is closed for the present.

Only a very little can be gathered on this point, but that little is almost as much as

we can expect or hope for. This is set down under three heads : —

I. Tlie points which the Striges share in common with the Accipitres and the Capri-

niulgi. These are : — The thick woolly covering of the nestling; the cervical, dorsal, and

ventral apteria ; aquintocubital wing ; nude oil-gland, agreeing in this point, however,

with the Cathartce and Caprimulgi, but not with the Accipitres ; and the rudimentaiy

( Caprimulgi) or even absent ( Cathartce and Fandion) aftersliaft.

II. Characters in which the Striges agree with the Falconiformes, but differ from the

Caprimulgi : — such as the presence of a cere in which the nostrils are jilaced ; the

arrangement of the dorsal wing-coverts, which resembles that of the FalconidcB ; the

presence of 12 rectrices and 11 retniges, though in the last particular they resemble

also the Coraciidce.

III. Points wherein the Striges differ- from the Falcoitiformes but agree with the

Caprimulgi or Coraciidce : — They are furnished by the soft dark phimage ; the restriction

of the adult down to the apteria ; and the covering of the podotheca.

The characters reckoned under the first section he regards as of little worth, belonging

as much to one group as the other ; whilst those of the second must certainly be allowed

to be of more importance than those of the third section ; though it is obvious that both

need further combination with other anatomical data, and this is done in Dr. Gadow's

work. The result is that he came to the conclusion that the nearest relations of the

Sttnges are the Caprimulgi, and especially Fodargns and Steatornis ; then follow the

Coracio', and finally the Cuculi.

I find myself unable to support Dr. GadoAv on two points. The first is that in which he

states that the neossoptiles of the Striges more closely resemble those of the Caprimulgi,

structurally, than those of the Accipitres ; and the second, wherein he states that the

down-feathers of both CaprimMlgi and Striges are confined to the apteria. As is else-

where pointed out (p. 257), the down-feathers of the Owls are structurally much more

nearly allied to those of the A ccijri ires than to the Ccqmnmlgi; and, lastly, the down-

feathers of both Owls and Caprimulgi are confined to ihe pderyla alaris and are absent

entirely from the apteria. 'J he downy covering of the nestling Owl, however, resembles

* Italics nre iiiin<'.

MOEPHOLOGT OF THE OWLS 269

that of tlie Capi-lmulgl and clitFevs froiu the Accipiti-es iu that it is appareutiy com^oosed

entirely of pre-pennce, whilst that of the Acclpiires is a mixture of pre-pennce and

pre-plumidcB. As a piece of additional evidence in favour of Dr. Gadow's position, I

would draw attention to the linear, transversely oljlique, arrangement of the dorsal

tectrices of the w^ini;-, which in this particu.lar agree with the Capnmulgi.

It seems evident that, in endeavouring to trace out the origin and Hues of descent of

any given group of birds, we can no more trust the evidence of pterylosis alone than that

of any of the other systems or organs that have from time to time been pressed into

service to this end, but that, judiciously combined with other characters, it Avill afford

help of some value. As an instrument for defining species it is possible that it may prove

a more reliable weapon, but this yet remains to be seen. It would be interesting to apply

this test to the examination of some of the reputed species and subspecies, or, as some

would have it, varieties of the Barn Owl, and see wliether or not the superficial differences

were accompanied by corresponding differences in the distribution of the feathers.

Key to the Families, Sifb-families, and Genera.

A. The median branch of tlie ventral tract free posteriorly ; the feathers of the hinder

border of the acrotarsiuni directed downwards ; no filoplumes at the end of the

oil-gland I. Asionid^.

a. Interscapular region of the pt. spinalis with a lon;^- bifurcation . . . Sub-fam. 1. AsionincB.

a'. Height of vertical axis of the external aperture of the ear three times that

of the horizontal axis of the eyelid.

a". Preaural and postaural folds voluminous, the former constituting an

operculum, which is provided with a valve; oil-gland napiform .... 1. Asiu.

b'. Height of the vertical axis of the exterual aperture of the car never exceeding

that of the horizontal axis of the eyelid; preaural fold not forming an operculum.

//'. Oil-gland conical ; cere not inflated, but closely investing the base of the

beak ; posterior division of the cavernum confined to its lower half ... 2. Bubo,

c". Cere laterally inflated, posterior division of the cavernum extending its whole [ 3. Scops.

vertical height 4. Ninox.

c. Vertical axis of the external aperture of the ear uot exceeding that of the hori- [ 5. Sceloglaux.

zontal axis of the eyehd ; preaural fold forming an operculum, the free edge

of which overlaps that of tlie pustaural fold.

d". Posterior division of the cavernum confined to its lower third ; peripheral

disc-feathers meeting in the middle line near the symphysis of the mandible ;

inner branch of the pt. ventralis arising over the region of the head of the

coracoid 6. Syrnium.

b. Interscapular region of the pt. .spinalis with a short bifurcation .... Sub-fam. 2. NyctalincB.

d' . Vertical axis of the external aperture of the ear twice that of the horizontal axis

of the eyelid ; pre- and postaural folds moderately well developed.

e". Cere short ; nostrils seated in pisiform inflations 7. Nyctala.

e . Vertical axis of the external aperture of the ear equal to that of the hori-

zontal axis of the eyelid ; no operculum ; cavernum divisible into anterior and

posterior portions.

J". Tail long and pointed ; oil-gland napiform 8. Surnia.

270 ME. \V. p. PYCEAFT ON THE

/'. Vertical axis of the external aperture of the ear half that of the horizontal axis

of the eyelid ; no operculum ; cavernum not divisible into anterior and posterior

portions.

g". Lumbar stem of pt. spinalis feebly developed or absent ; cere short, much ^ „ ^^ .

inflated, forminff two pisiform swellings on either side of the culmen . . A ,„ ■*„ ' -

[ 10. Speotyto.

Key to the Species of the Family Asionidae.

Genus 1. Asio.

a. Lateral ucck-folds voluminous, with an oblique retractor eusheathed in a

prominent membranous fold.

a'. Upper end of the dorsal lateral neck-fold lobate ; diverticulum of the

cavernum broad and shallow, the membrane shutting off the via recta

passing over a bony tubercle of the postorbital process L A. accipitrinus.

b'. Upper end of dorsal lateral neck-fold not lobate ; diverticulum of the

cavernum narrow and deep ; no postorbital tubercle 2. A. otus.

Genus 2. Bubo.

a. Vertical axis of the external aperture of the ear equal to the horizontal

axis of the eyelid.

a'. Interramal not connected with the ramal area ; interscapular fork

with very long branches \. B. ignavus.

b'. Interramal fused from gape backwards with the ramal area, which

extends beyond the articular region of the jaw ; interscapular fork

with very short branches ; lateral neck-folds with an oblique retractor

as in Asio 2. H. virginianus.

c'. Interramal area contracting suddenly behind the region of the gape

to form a narrow band ; median and inner ventral tract sharply

defined ; apt. colli lateralis continued upwards on to the crown of

the head Z. B. maculosus.

b. Vertical axis of the external aperture of the car less than the horizontal

axis of the eye.

d'. Interramal joining the mandibular area at the gape ; interscapular

fork with very short branches ; lateral neck-folds without a retractor. 4. B. torquatus *.

e'. Interramal area joined, by two separate single rows of feathers behind

the gape, with the ramal area ; interscapular fork with very long

branches ; cavernum not divisible into anterior and posterior

portions 5. JS. lacteus.

e. Aperture of the external ear pyriform. Interramal joined to the

mandibular area in front of gape by a single row of feathers, behind it

by a very broad baud ; interscapular fork with very long branches . . 6. B. nycteus.

* This = the Pulsatrix iorquains (Daud.) and the Syrnmm jierspicillatum of Latham.

MOEPHOLOGT OF THE OWLS. 271

|'3. Scops.

Genus p'. Ninox.

[5. SCELOGLAUX.

a. Vertical axis of the external car equal to the horizontal axis of the

eyelid ; interramal joined to ramal area by a broad expansion from the

gape backwards; mandibular area extending backwards bcliiud tlie

jaw 1. Scops leucotis.

b. Vertical axis of the external aperture of the ear half the horizontal axis

of the eyelid ; interramal joined to ramal area behind the level of the

gape by a narrow branch running obliquely backwards ; ramal area

narrow, not extending backwards beyond the level of the jaw ; lateral

neck-folds and oblique retractor ; eyelids with a pectinated edge , . . 2. Scops (/lu.

c. Vertical axis of the external aperture of the ear nearly equal to the

horizontal axis of the eyelid 3. Ninox nnva-zealandice.

d. Vertical axis of the external aperture of the ear equal to the horizontal axis

of the eyelid ; interramal area broad, expanding to merge with tlie

mandibular area at the gape ; arms of the interscapular fork long,

arising high up ; stem of lumbar fork very wide, arms short, closely

approximated, expanding distally ; inner and median branches of the

pt. ventraJis imperfectly defined 4. Sceloglaux albifacies.

Genus 6. Sykmum.

a. Vertical axis of the external aperture of the ear of the left side less than

the horizontal axis of the eye ; that of the right side greater than this

axis; interramal ai'ea tapering gently backwards \. S. aluco.

b. Vertical axis of the right and left external apertures of the ear equal, and

greater than the horizontal axis of the eyelid ; interramal fused with

the mandibular area from the gape backwards 2. S. uralense.

Genus 7. Nyctala.

Vertical axis of the external ajierture of the ear twice the horizontal axis of

the eyelid ; loreal area nearly divided into two parts by an apterium ;

interscapular portion of the pt. spinalis with a barely perceptible

fork 1. A^, Tengmalmi.

Genus 8. Surnia.

Vertical axis of the external aperture of the ear equal to the horizontal

axis of the eyelid ; interramal merging with the ramal area from the

gape backwards ; lateral neck-folds with an oblique retractor . . . \. S. ulula.

( 9. Carine.

Geuus< „

( 10. OPEOTYTO.

a. Vertical axis of the external aperture of the ear equal to the horizontal

axis of the eyelid.

a'. Loreal area not divided by an apterium ; interramal joining the ramal

area at the gape, and contracting suddenly immediately after to

become the pt. colli venlralis ; lateral neck-folds with au oblique

retractor . , 1. Carine noctua.

SECOND SERIES. — ZOOLOGY, VOL. VII. 37

272 ME. W. P, PTCKAPT ON THE

b'. Loreal area completely divided into two pai'ts by a broad apterium ;

interiatnal area joining the ramal area at the gape, and continned

backwards as a broad band to the articular end of the jaw; inter-

scapular fork in the form of two short arms 2. Speotyto cunicularia.

B. The median branch of the ventral tract joining the inner branch poste-

riorly ; the feathers along the hinder border of the acrotarsium directed

upwards ; the oil-gland bearing two or three filoplumous feathers at its

tip II. StrigidvE.

External aperture of the ear quadrangular ; the vertical axis half the hori-

zontal axis of the eyelid ; preaural fold forming a large operculum ;

interramal area unconnected with the ramal area 1. Strix fiammea.

List of Works quoted or referred to.

1. Beddahd, F. E. — "On PhotodUus badim, with Remarks on its Systematic Position/' Ibis, ser. 6,

vol. ii. p. 293 (1890).

2. Gadow, H. — ' Bronn's Klassen uud Ordnung. des Tierrcichs,' Viigel, Anatomischer Theil, pp. 541,

551, 569-570 (1891).

3. Gadow, H.— Ibid., Systemat. Theil, p. 235 (1893).

4. Gadow, H.— In Newton's ' Dictionary of Birds,' p. 178 (1893).

5. Garrod, a. H. — " On some Points in the Anatomy of Steatornis." Proc. Zool. Soc. 1873, pp. 526-

535.

6. GooDCHiLD, J. G. — "The Cubital Coverts of the Euornithce," Proc. Roy. Pliys. Soc. Edinb. vol. x.

(1890-91), pp. 317, 333.

7. GuRNEY, J. H.— "On Sceluglaux albifacies," Trans. Norf. & Norw. Nat. Soc. vol. vi. p. 154 (1896).

8. Kaup, J. J.—" Monograph of the Strigidai," Trans. Zool. Soc. vol. iv. pp. 201-260 (1862).

9. Meijere, J. C. H. DE. — " Uber die Haare dor SLiugethiere, besonders iiber ihre Anordnung,"

Morph. Jahrbuch, Bd. 21, 1894, pp. 312-424.

10. Meijere, J. C. H. de. — " Uber die Federu der Vogcl, insbesondere iiber ihre Anordnung," Morph.

Jahrbuch, Bd. 23, 1895, pp. 5G2-591.

11. Newton, A.—' Dictionary of Birds,' pp. 671,638, 394 (1893-96).

12. Newton, A.—' Yarrell's British Birds,' ed. iv. vol. i. pp. 147, 161-162 (1874).

13. NiTzscH— ' Pterylography,' English Trans., pp. 66-67 (1866).

14. Pycraft, W. p. — " A Contribution to the Pterylography of Birds' Wings," Trans. Leicester. Lit.

& Phil. Soc. vol. ii. 1890, pp. 3-24.

15. Pycraft, W. P. — " On the Pterylography of the Hoatzin, Opisthocomus cristatus," Ibis, ser. 7, vol. i.

pp. 353-354, 356, 359 (1895).

16. RiDGWAY.— ' A ISIanual of N. Amer. Birds,' 2nd ed. 1896, p. 255.

17. Sharfe. — 'Cat. Birds Brit. Mus.' vol. ii. Striges (1875).

x8. Sharpe.—' Allen's Naturalist's Library,' vol. ii. pp. 76-111 (1896).

ig. Shufeldt, R. W. — "Notes on the Anatomy of Speoti/to cunicularia hy pogtea, " iouvn. Morphol.

vol. iii. 1889, p. 115.

20. SuNDEVALL, C. .).— "On the Wings of Birds," Ibis (Reprint), Oct. 1886.

21. Wray, R.— " On some Points in the Morphology of the Wings of Birds," P. Z. S. 1887, p. 343.

MOEPHOLOGT OF THE OWLS. 273

EXPLANATION OF THE PLATES.

(All the figures are original.)

Plate 24.

Fig. 1. Dorsal aspect of the left wing of an adult Asio accipitrinux, showing the disposition of the

remiges and tectrices. The latter are remarkable for the fact that on the fore-arm they are

arranged not in quincunx, but set in obliquely transverse rows, running from without inwards

as in Caprimtdgus and Rhen. — Note the position of the jilumuke (d. f.).

d.f Down-feather.

1st — 6th cub. rem. . . 1st — 6tli cubital remcx, or secondary.

1st — 5th maj. cov. . . 1st — 5tli major covert.

P Parapteron.

3. 2. 1 ]\Ietacarpal remiges, or 1st 3 primaries, numbered from

the wrist outwards.

1. 2. 3 Cubital remiges or secondaries, numbered from the

wrist inwards.

Plate 25.

Fig. 1. Dorsal aspect of an adult Asio accipitrinus, showing the arrangement of the pterylae. The

dotted areas represent the pterylte ; the relative sizes of the feathers are indicated by large and

small dots.

Apt. coll. d Apterium colli dorsale.

Apt. coll. lat „ colli laterale.

Apt. sp „ spinale.

E Eye.

H Feather " horn " or " ears."

Pt. al Pteryla alaris.

Pt. cap ,, capitis.

Pt. caud „ caudalis.

Pt. coll. d ,, colli dorsalis.

Pt. cr „ cruralis.

Pt. f. ,, femoralis.

Pt. hum ,, humeralis.

Pt. sj) ,, spinalis.

Fig. 2. Left side view of the same. The dotted parts as before.

Apt. m Apterium niesogastrsei.

Apt. t. 1 ,, trunci laterale.

L. a Loreal area.

m. f. Muscular fold.

Op . Operculum.

Postaur. f Postaural fold.

Pt. coll. vent Pteryla colli ventralis.

Pt. v „ ventralis.

R. a Ramal area.

Note the oblique muscular fold (m. f.) running down the neck.

Fig. 3. Ventral aspect of the same. The dotted parts as before.

Pt. cl Pteryla aui s. cloaci.

274 ME. W. p. PYCEAFT ON THE

Plate 26.

Figs. 1, 2, 3, 4, 5. Dorsal views of Nyctala Temjmalmi, Speohjto cunicularia, Scops leucotis, Bubo

711/cteus, and Bubo mactilosvs, to show the form of the spinal tract. — Note the upward extension

of the apt. coll. Lit. in B. maculosus.

Fig. 6. Ventral view of Syrnium aluco to show the form of interramal area and the pt. ventralis.

Letters as before.

Plate 27.

Fig. 1. Left side view of the head of an adult Asio otus, to show the form and great size of the external

aperture of the ear. This should be compared with tig. 2 — the right side of the same head-

to show the asymmetrical development of the two sides, and with fig. .3 opposite, to compare

the differences between A. otus and A. acripiirinHS .

d Diverticulum.

M Mandible.

M. e Meatus externus, s. via recta, p. 262.

Op Operculum s. preaural fold.

P. f. Postaural fold.

R Rim.

S Skull.

The cavcrnum (p. 259) includes the whole space surrounded by the pre- and postaural folds ; the

portions M.e. and d. separated one from the other by the valve represent the posterior division of the

cavernum of Bubo and Scops.

Fig. 2. Right side view of the same head. Letters as before.

Fig. 3. Left side view of the head of an adult Asio accipitrinus, to show the form of the external ear.

Compare with fig. 1 to make out the diftcrcnccs between this and A. otus, and with fig. 4 to

make out the asymmetrical development of the two sides. — Note the presence of a postorbital

tubercle, affording support to the valve. This is wanting in A. otus.

* Postorbital tubercle.

Fig. 4. Right side of same head. Letters as before.

Fig. 5. Left side view of the head of an adult Nyctala Tengmalmi, to show the form of the external

aperture of the ear. This should be compared with fig. 6, the right side view of the same head,

to note the very asymmetrical development of the skull-boues on the two sides of the head.

t. w. sq Tympanic wing of the squamosal.

q. j Quadrato-jugal.

Fig. 6. Right side view of same head. Letters as before.

Fig. 7. Anterior view of the skull of Nyctala Tenynialml, from a specimen in the Cambridge Museum'

of Zoology, to show the asymmetrical arrangement of the skull-bones.

P. o. p Postorbital process.

Plate 28.

Fig. L Left side view of the head of an adult Syrnium aluco, to show the form of the external aperture

of the ear. Compare with fig. 2 — the right side view of the same head — to show the

asymmetry in the size of the two apertures ; and with fig. 4 to show the difi'erence between

the ears of R aluco and Stria: flammea.

D Peripheral disc-feathers.

MOKPHOLOGT OF THE OWLS. 275

Fig. 2. Right side view of the same head. Letters as before.

Fig. 3. Left side view of the head of an adult Scops lencotis, to show the form of the external aperture

of the ear. — Note the anterior and posterior divisions of the cavernum, described on p. 259.

Letters as before.

Fig. 4. Left side ^-iew of the head of an adult Strix fiammea , to show the form of the external aperture

of the ear (see p. 263). Letters as before.

Fig, 5. Right side view of the head of an adult Speotyto cunicularia, to show the form of the external

aperture of the ear. — Note the small size of the aperture, and the spiral arrangement of the

feathers seated in the pre- and postaural folds. Letters as before.

Fig, 6. Left side view of tlie head of an adult Niiiox novce-zealandice, to show the form of the external

aperture of the ear. Letters as before.

Plate 29.

Fig. 1. Dorsal aspect of an adult .S7rM\//f/»?wiec, showing the arrangement of the pterylse. The dotted

parts as before. Letters as before.

Fig. 2. Left side view of the same. — Note the absence of lateral neck-folds and the outward turning of

the inner branch of the pt. ventralis. Letters as before.

Fig. 3. Ventral view of the same. In this figure the characteristic outward direction of the caudal end

of the inner branch of the pt. ventralis is well seen. Letters as before.

SECOND SERIES. — ZOOLOGY, VOL. VII. 38

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3nd Ser. ZOOLOGY.]

[VOL. VII. PAET 7.

AUG 20 ^S99

THE

TRANSACTIONS

OF

THE LINNEAN SOCIETY OF LONDON.

THE BRAIN IN THE EDENTATA.

BY

G. ELLIOT SMITH, M.D. (Sydney),

ST. John's COI.I.EHF, CAMBIilDGE.

[Comiaunlciiti-'d by Prof. (1. B. Howes, Sec. Linn. Soc.)

LONDON:

PRINTED FOR THE LINNEAN .SOCIETY

BY TAyi.OK AND FRANCI.S, KKI) I.IOK COURT, Kl.KKT STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BUBLINGTON-IIOUSB, PICCADILLY. W.,

AND BY LONGMANS, GREEN, AND CO., FATERNOSTER-ROW.

Janiianj 1899.

277 ]

VII. The Brain in the Edentata. By G. Elliot Smith, 3I..D. (Sydnetj), St. Johrs

College, Cambridge. {Communicated Ity Prof. G. B. Howes, F.R.S., Sec. Linn. Soc.)

(With 36 Illustrations in the Text.)

AUG 29 '^^^- Eead 7th April, 1898.

Introduction.

The interest which attaches to the study of the brain in any large group of animals is

considerably accentuated in the case of such an enigmatical order of mammals as that

discussed in this communication. Two aspects of this many-sided interest must appeal to

us very forcibly during the investigation of the strange assemblage of mammals which have

been gathered into one group under the name Edentata. For we may not unreasonahly

hope tbat the obscure problems of the interrelationships of the heterogeneous families

which compose this so-called " order," and the even more perplexing question of the

wider affinities to other groups of animals, may be elucidated by the evidence afforded

by the brain, which, as the master-organ of the body, must be allowed distinctive

importance.

Then, again, the study of so many modifications of the mammalian type of

brain as we find within the limits of this group must exercise a considerable

influence upon the more strictly morphological problem of the " search alter the

fundamental lines in the structure of the brain," which, as Edinger has well said, is the

most important task of the brain-anatomist of the present day. This aspect of the

problem becomes all the more interesting in the case of a group of mammals like the

Edentata, wliich it is customary to regard as of lowly organization, when we remember

that changes of great significance, which must appeal equally to the systematist and the

morjjhologist, have taken place in the structure of the brain within the Mammalia.

For we find certain features in the cerebrum of the Monotremata and MarsupiaUa

which distinguish these groups clearly the one from the other and each from all the

Eutheria *. If the Edentata are as lowly organized as they are generally represented,

we might reasonably expect to find some definite evidence of this fact in those regions

of the brain which we know to have heeii so transformed at the birth of the Placentalia.

On the contrary, should the results of an examination prove that these recently modified

parts of the brain show the typiaxl features as fully developed as they are in such

Eutheria as the Ungulata or Carnivora, we might be justified in adopting this as

strong corroborative evidence in favour of the view that there is a much closer affinity

between the ordinary Eutheria and the Edentata than is usually supposed.

* These features I have alread}' discussed before this Societj' (' The Origin of the Corpus Callosum, &c.,'

Traus. Linnean Society, 2nd series, Zoology, vol. vii. jjart 3, 1897), and elsewhere ; c/. ' Journal of Anatomy and

Physiology," vol. xsxii. pp. 23-58, 1897.

SECOND SERIES. — ZOOLOGY, VOL. VII. 39

278 DK. G. ELLIOT SMITH ON

In tliis investigation our first aim must be the determination of the extent to which

the hrain in the Edentata conforms to the architectural plans which prevail elsewhere in

the Mammalia. Tlicn we shall be able to appreciate the modifications of the jirevalent

tjpe or types and study the factors M'hicli produce these variations, either to meet direct

physiological needs which the mode of life of the individual imposes, or to conform, to

some definite morphological plan which is not so directly the expression of functional

modification, and therefore is likely to have some definite taxonomic value.

Before entering into the discussion of these problems, it will be well to review as briefly

as possible the state of our knowledge concerning the relationsliips of the Edentata at the

present time.

It \^ ould perhaps be difficult to discover elsewhere am.ong the Mammalia five natural

groups of mammals which present such striking contrasts in appearance and habits of

life as we find in the five families which include all the existing Edentata. Striking as

these contrasts are, they are probably equalled by the marked diff'erences in the

anatomical features of the animals. The only reason for uniting these heterogeneous

families in one group is the fact that they possess in common certain negative characters

which distinguish them from all othei- mammals. The most important of these negative

features is the roducticn of the teetli, but even the characters of this reduction, the

featiu'es of the few teeth Ihat remain in certain families, and the little we know of their

development present most manifest distinctions.

In spite of the absence of any very decided anatomical links between the different

recent families, the evidence of palgeontoiogy many years ago showed that both the

Sloths and Ant-eaters, although markedly dissimilar in themselves, exhibit signs of close

kinship to the extinct Ground-Sloths. Moreover, it is now very generally admitted that

the Armadillos also branched off at an early period from a stock common to the

ancestors of the Ant-eaters, Sh)ths, and Ground-Sloths. Hence Gill* has suggested the

separation of these three New-World families as a suborder from the Old-World families.

To this suborder he gives the name Xena)-thra, because in these American families the

zygapojjhvses of the vertebrae possess additional articular facets.

The Imge collections of extinct Tertiary mammals which have been unearthed within

recent years have tlii'()\\ n a considerable amount of light upon the vexed problems of the

kinship of the Edentata.

If we admit that the group of extinct mammals which Wortman has called Ganodontaf

represents the ancestors of the American Edentata, we must 1 e prepared to recognize in

the latter the degenerate representatives of a group of animals which are imited by

the closest ties of kinsliip to the ancestors of the Eodentia, Carnivora, and Ungulata.

It is not necessary to do more than mention in passing how vastly this suggestion is at

variance vdih the older and as yet more generally accepted view that the Edentata are a

very primitive group, which is so distantly related to the ordinary Eutheria that some

* Gill, ' Standard Katural History,' 1884.

t S. L. ■\Vortmaii, ' Psittacothcrium, a Member of a New and I'limitive Suborder of tlie Edentata,' Author's

edition, copied frcm tlio Hull. Amer. Mus. Nat. Hist. vol. viii. aitiele ivi. p. 259 (189t)).

THE BliAIX IN THE EDENTATA. 279

writers even suggest tlieir separation as " Paratheria." Wortman's liypotlicsis brings

the Edentata into intimate relationship with the o'dinary Eutlieria, and is quite fatal to

the Pavatherian idea.

The anatomical features of the two Old-World families, the scaly Pangolins (the

habitat of which fringes the Asiatic continent from the Ethiopian I'egion in the wesc to

the islands at the extreme south-east) and the Ethiopian Onjcleropus (the pig-like

appearance of which suggested the name Aai-d-vark, which the Dutchmen of the Cape

apply to it), probably differ the one from the other and each from the American forms

as widely as their geographical distrilmtion, and concerning tlieir ancestry palaeontology

has not revealed much. The present state of our knowledge, or lack of knowledge, of

the affinities of the Pangolins and the Aard-varks has been aptly and forcibly expressed

by Oldtield Thomas. Writing of Orycteropus he says *: —

" Although called an Edentate, it has always been recognized as possessing many

characters exceedingly different from those of the typical American meml)ers of the

order. It has been placed with them rather on account of the inconvenience of forming

a sj)ecial order for its reception than because of its real relationship to them. Now, as

they are altogether toothless or else bomodont and raonophyodont (apart from the

remarkable exception of Tatusla), it seems more than ever incorrect to unite with them

the solitary member of the TubuUdentata, toothed, heterodont, and diphyodout, and

differing from them in addition by its placentation, the anatomy of its reproductive

organs, the minute structure of its teeth, and the general characters of its skeleton.

" But if Orycteropus is not genetically a near relation of the Edentates, we are wholly in

the dark as to what other mammals it is allied to, and I think it would be premature to

hazard a guess on the subject. Whether even it has any special connection with ITanis

is a point about which there is the greatest doubt, and unfortunately we are as yet

absolutely Avithout any palaeontological knowledge of the extinct allies of either.

Maci'otherinm even, usually supposed from tlie structure of its phalangeal bones to be

related to Munis, has been lately proved to have the teeth and vertebra? of a Perisso-

dactyle Ungulate, and one would not dare to suggest that the ancestors of Maitis or

Orycteropus were to be sought in that direction. Lastly, as tlie numerous fossil

American Edentates do not show the slightest tendency to an approximation towards

the Old- World forms, we are furnished with an additional reason for insisting on the

radical distinctness of the latter, whose phylogeny must therefore remain for the j)resent

one of the many imsolved zoological problems."

I have quoted these conclusions at some length because they summarize so admirably

our present state of ignorance of the interrelationships of the Edentata as a grou^). Nor

is our knowledge of the relationsliip of the group to the other Mammalia on a more

satisfactory basis. It is, therefore, strange that so little has hitherto been done to call

in the evidence which the nervous system, and especially the brain, affords to help to

unravel this perplexing tangle of relationships. Eor it is hardly conceivable that the

master-organ which presides over the activities of the whole body, and is responsive to

* Oldfield Thomas. ' A Milk Dentition in Ori/ctei-ojnis,' Proceedings of the lloyal Society, vol. xlvii. (1890) p. 248.

39*

280 DR. G. ELLIOT SMITH ON

every change of bodily conformation and every variation in the physiological activity of

the organism — which, in a word, is the only part of the body which can be said to

represent within iheli all parts of the organism — could be other than an index of

undoubted taxonomic value. But at the present time there is an u.nfortunate tendency

among systematists to lightly esteem the value of the brain in this connection, and

either to ignore cerebral features altogether or pay them such scant attention as

practically amounts to the same thing. Such loose and utterly erroneous statements as

those of Cope, who laconically sums up the characters of the Edentate brain in the

words " hemispheres small, smooth " *, are unfortunately only too often found in the

writings of comparative anatomists of the present day.

In considering the peculiarities of the brain in any group of mammals it is necessary

to distinguish those features which are dependent upon mere functional modification

from those which, though not altogether independent of function, are yet the expression

of a definite morphological type. For example, we find that the mesencephalon in

almost all mammals conforms to a definite unchangeable morphological type, althoixgh

the proportions of its various parts undergo the most notable variations as the functional

importance of the visual and auditory activities varies. On the other hand, in the

cerebral hemisphere we also find evident changes which can be directly traced to

functional modification in association with the varying acuteness of the sense organs,

while beyond these modifications we find other changes which cannot be explained as

purely functional variations, but which are beyond question the expression, as afore-

said, of a definite morphological type.

In seeking for evidence to aid in the interpretation of such jiroblems as thesc^ I have

not hesitated to cull data from examination of widely differing types. My studies of

the Edentata were preceded by an examination of the brain in the Monotremata and

Marsupialia, and during the course of this examination I have constantly compared the

features of the brains under consideration with those of such representatives of the

Tnsectivora, Eodentia, Cheiroptera, Ungulata, and Carnivora (among other groups) as

-were available for the piirpose.

The results of the only attempt which has hitherto been made to discuss the anatomy

of the brain in the Edentata in a systematic manner are embodied in a memoir by

(reorges Pouchet, which was published thirty years agot- But many other anatomists,

both before and since the time of Pouchet, have given us brief descriptions of the brain

in individual members of this group. The extreme variations in external configuration

which the brain presents in different members of the so-called order have been made the

subject of an admirably illustrated memoir by Paul Gervais, which made its appearance

contemporaneously with Pouchet's contribution J. Even to this day Pouchet's work is

* Cope, ' Origin of the Fittest,' 1878, p. 342.

t G. Pouchet, 'ilemoire sur I'Encephale des Edcntes,' Joiinial de TAuatoinie ct de la Physiologie, tome v. 18fiS

110. G, and tome vi. 1869, nos. ], 2, 3, & 4.

J Paul Gervais, ' Memoircs sur les Formes cerebralcs propres aux Edentes vivauts ct fossilcs,' Nouvellei

Archives du Museum d'Histoirc natnrelle de Paris, tome v. (ISGO).

THE BRAIX I^" THE EDENTATA. 281

the only attempt to treat in a comprehensive manner the anatomy of the brain in the

whole group. But Pouchet's memoir is altogether inadequate to our present needs.

During tlie thirty years that have elapsed since this work was published the outlook of

the student of brain anatomy has been immeasurably widened, his methods of investi-

gation have been utterly changed, and his whole science has been revolutionized. The

investigator of to-day approaches the study of a new type of brain with a much better

equipment and a considerably clearer appreciation of the significance and relative

importance of anatomical features than was possible before Weigert, Golgi, and Marclii

introduced methods of research which have enabled us to understand the fundamental

plan of the organ with which we have to deal. Instead of describing in a more or less

casual manner the general features of a brain as Pouchet did, and thereby accumulating

a mass of evidence which is valueless to a succeeding generation, we can, in the light of

our present-day knowledge, directly examine with a clearly defined purpose those parts

of the brain which we know are undergoing change in the Mammalia. Of all parts of

the brain the most recently differentiated portion, the cerebral cortex, is naturally that

which is the most changeable, and to which most of our attention must necessarily

be devoted. In studying this more than any other part it is necessary to institute

comparisons with as wide a series of mammals as possible, in order to gain an insight

into the significance of such modifications as we find.

In the light of our knowledge of. the important differences which exist between the

hippocampal formation and the cerebral commissures in the Monotremata and Marsupialia,

and between each of these orders and the so-called Placentalia, I have entered into the

consideration of this aspect of the problem in some detail. The regions of the brain-

stem, the optic thalamus, the mesencephalon and hind-brain, have been described as briefly

as is consistent with clearness, because these stable regions of the brain are subject

to very slight variations as compared M'ith the great modifications which affect other

regions.

In considering the cerebellum I have entered into the descriptions in considerable

detail because, unfortvmately, the subject of cerebellar morphology is almost a term

incognita. For the purposes of this paper I have found it necessary to examine the

cerebellum in as many mammalian brains as were obtainable, in order to arrive at some

idea of the fundamental plan according to which this complex organ was built up. As

the result of this extensive examination I have elaborated a tentative scheme for

describing the cerebellum, the chief merit of which is its extreme simplicity, and the

fact that it is applicable to the cerebellum in any member of the Metatheria or

Eutheria. This can hardly be said of the method of description which is employed in

human anatomy, and which is practically the only system of nomenclature thus far

adopted in discussing the cerebellum.

In certain of the better known regions of the brain I have found it necessary to enter

into much longer explanations than might otherwise have been needed if the nomenclature

liad not been so confused. As an examjile I mtiy refer to the region of the pyriform lobe.

^J.So far as was possible with the material at my disposal I have investigated the

histology of the brains considered in this contribution, and in the case of Chlamydophorus

282 DR. G. ELLIOT SMITH ON

a series of coronal sections was carefully examined. But in none of these brains was it

possible to detect any histological features which could not be demonstrated much more

clearly and to much better purpose in the fresh brains of such Insectivores and E^odents

as are always available. Tor this reason I have not felt justified in giving illustrations

to represent histological facts, although my descriptions, and to some extent the

figures which accompany these descriptions, are largely based upon the results of

histological examination.

When Professor Howes kindly suggested that I should undertake this investigation,

he very generously placed at my disposal all the Edentate brain-material which his

teaching-collection contained. This nucleus of material, ujwn which most of the

investigation was carried out, consisted of a very well preserved specimen of the brain

of an adult Orycteropus, as well as representatives of Tamanclua tetradactyla, Choloepus

didactijlus, and ChJamyclophonis truncatiis, in a somewhat less satisfactory state of

preservation. All these brains had been preserved in alcohol.

Professor Max Weber, of Amsterdam, very generously gave me, on the suggestion of

Professor Howes, the brain of a young Bradypus tridactylus, which had been carefully

preserved in a chromic solution, so that it was available for histological work *.

The magnificent collection of brains in the galleries of the Museum of the Royal

College of Surgeons in London inchides a valuable series of fifteen Edentate bi'ains,

and to these Professor Stewart kindly gave me free access. In this collection are

to be found representatives of the genera Orycteropus, Ilyrmecophaga, Tamandua,

Bradypus, Choloepus, Dasyp)us, Xemirus, Tutnsia, Tolypentes, and Munis. The Museum

also contains cranial casts of Choloepus and the extinct forms He gather ium and

Glyptodon.

In addition to this, Professor Stewart very kindly placed the resources of his stock at

my disposal, and from this collection I obtained representatives of Dasijipus rillosus,

Bradypus tridactylus, a small Mauis of unknown species, and a number of partially

dissected brains, more especially of 3Iyrmecop)haga and Choloepus.

Prom this it will appear that representatives of every genus except Cycloturus and

Priodon have been available for examination ; but, as the subsequent account will show,

we have imperfect data which, by comparison with other representatives of the same

families, will enable us to form a tolerably aiDproxiraate estimate of the configuration of

the brain in the Little Ant-eater and the Great Armadillo.

Among the beautiful series of drawings which the late Professor Huxley bequeathed

to the Hoyal College of Science, there are sketches of the brains of Orycteropus,

Tamandua, and Dasypus sexcinctus, none of which liave been published. Professor Howes

has kindly allowed me to make use of these, and, as two of the sketches represent

the appearance in the fresh state of the actual brains of Orycteropus and Tamandua

whicli were used in this investigation, they proved of service in preparing rigures

3 and 25.

* This brain is apparentlj- the second brai)i of Bradi/^ms whicli is referred tu in I'rofessoi' Max Weber's memoir,

" Vorstudien liber das Hirngewieht der Saugcfhiere," Sejiarat-Abdruck aus Festschrift fiir Carl Gegenbaur,

Leipzig. 18n(), p. 10!J.

THE BKAIX IX THE EDENTATA. 283

To Professor Max Weber and Professor Ste\yart I miist here express my deeiJ sense of

gratitude for their generosity in plaeing such Aahiahle material at my disposal, and in

addition I must thank the latter gentleman for granting me for some weeks all the

facilities which his laboratory offers.

My indebtedness for so much material for this research and the opportunities for making

use of his laboratory is among the least of my many obligations to Professor Howes,

who has constantly guided me in the search for literatui'e, and has ever been ready to

give me the benefit of his valuable advice. It is with the greatest pleasure that I take

this opportunity of acknowledging all this kindly consideration.

Literature.

Reckoned by the number of memoirs Avhich have appeared upon the anatomy of the

brain in the Edentata, it must be confessed that the literature is by no means incon-

siderable; but v/hen we j^roceed to sum up the positive additions to exact knowledge, we

are bound to confess that an acquaintance with the Edentate brain derived from this

bulky mass cannot be otherwise than very liazy.

In the following table these contribiitious to our knowledge of this subject are arranged

in chronological order : —

P. TiEBEMANN. — ' Icoues Cerebri Simiarum et quorumdam Mammalium rariorum.'

Heidelberg, 1821.

Contains figures representing the dorsal and mesial surfaces of the brain of (JJiolieptis didactiflns and the dorsal

surface of the brain of Ci/chtitnis Jidacti/lus.

P. Leuret et P. Gratiolet. — ' Anatomic comparee du Systeme nerveux.' Paris,

1839-59.

Contains the figure of the dorsal surface of the/brain of Brinli/piis IriJarti/lns, and in the text numerous references

to the brains of other Edentates.

WiLHELM VON Rapp. — ' Anatomische Untersuchungen iiber die Edentaten.' Geneva,

1843 and 1852.

The dorsal surfaces of the brains of Cliolcepus and Tdtnsia are represented.

J. Hyrtl. — " Chlamydophori tnaicati cum Daanpode gymnnro comparati examen

anatomicum." Denkschr. d. k. Akad. d. Wiss., Vienna, 1855.

Contains a few brief notes on the brain of CIilitiin/i!oj>honis, unaccompanied bj' any figures.

Alessandrini. — " Ceuni suU' Anatoniia del Dasipo minimo, Desm." Mem. Pi. Accad.

delle Se. dell' 1st. di Bologna, t. vii. 18-36.

Contains very brief and unimportant notes on Tatuna.

W. H. Elower. — " On the Commissiu-es of the Cerebral Hemispheres of the Marsvipialia

and Monotremata." Philosophical Transactions, 1865.

In this classical memoir the mesial surface and a coronal section through the cerebrum of Choloqnis didaciylus

have been represented in figures with an exactness whicli is lacking in the eai'lier memoirs.

W. Turner. — " On the Anatomy of the Brain of Dasi/jnis sexcinctus.'' Jom-nai of

Anatomy and Physiology, vol. i. 1867.

The most complete account we possess of the Ijrain of Dasijpus scJ-'cinctus, illustrated by three figures.

284 DE. G. ELLIOT SMITH ON

Georges Potjchet.— " Memoire sur FEncepliale des Edeutes." Journal de I'Anatoinie et

de la Physiologie, tome v. 1868 aud tome vi. 1869.

In this important work figures of tlie actual brain in the genera Tamandua, Ci/doturus, Chlamydopliorm,

Dasypus, Manis, and foetal specimens of Bradypus, Cholcepus, Tatasia, and Orycterojnis, have been given in

addition to cranial casts of Cholcepus, Orncteropus, Mylodon, and Glyptmhn.

I have been unable to consult Pouchet's earlier " Memoires sur le grand Fourmilier."

Patil Gervais. — "Memoire sur les Formes cer^brales propres aux Edentes vivants

et fossiles." Nouvelles Archives du Museum d'Histoire naturelle de Paris,

tome V. 1869.

Contains an excellent series of figures of cranial casts of all the representative existing genera of Edentates as

well as most of the extinct forms. In addition there are figures of the actual brain of Mynnccophaya, Manis,

Dasypus se.vcinctus, and a young Orycteropus.

A. H. Gabeod. — " Notes upon tlie Anatomy of Tolypeutes tricinctus, with remarks upon

other Armadillos." Proceedings of the Zoological Society of London, 1878,

pp. 222-230.

The earliest description of the brain of Tolypeutes : in addition the author describes, with an excellent illustration,

tlie brain of Xenurtis.

W. A. EoBBES. — " On some Points in the Anatomy of the Great Ant-eater {Myrmecophaga

jubata)." Proceedings of the Zoological Society of London, 1882.

The best account of the brain of Myrmecopliaya yet published.

W. TuRNEB. — "The Convolutions of the Brain." Journal of Anatomy and Physiology,

vol. A-xv. 1890.

Professor Turner adds brief notes and two figures of C'holoepus Iloffmanni to his previous contribution dealing

with Basypns.

H. Eabl-Puckhabd. — " Einiges iiher das Gehirn der Edentata." Archiv fiir mikro-

skopische Anatomic, Bd. xxxv. 1890.

This brief memoir represents all that has hitherto been accomplished towards the elucidation of the histology of

the brain in Edentata, and concerns itself merely with the anterior commissure and the presence of a longitudinal

ependymal fold in the roof of the aqumductus Sylvii of a foetal Xenurus. The most valuable feature of this memoir

is the excellent series of figures of sections stained by the method of Weigert.

Max Webeb. — " Beitrage zur Anatomic und Entwickclung des Genus Manis."

Zoolog'ische Ergebnisse einer Kcise in Niedcrlandisch Ost-Indien II., Leyden, 1892.

Contains the best description of the brain of Manis hitherto published, with illustrations.

At the time when this investigation was undertaken the literature included in the

above list represented all that had hitherto been published (so far as the writer is aware)

concerning the anatomy of the brain in the Edentata. But since the present memoir was

announcedj Professor Howes has kindly called my attention to a brief note concerning

a monograph upon this subject, which unfortunately has not been publislied *.

Quite recently Ziehen has published some comparative notes upon the brain of Manis

in the first part of a large monograph upon the brain in Monotremata and Marsupialia t .

* George Hu.xtington. — " Contributions to the Visceral Anatomy of Myrmecophaga jubata, Tamandua hivittata,

Arctopitheciis didactylns, Dasypus sexcincins, Tatusia novemcincta, and Manis lotiyicaudata." [Abstract.]

Transactions of the New York Academy of Sciences, vol. xv., January 1896, p. 98.

t TuKODOK Ziehen. — " Das Centralntrvensystem der Monotremen und Marsupialier." 1 Theil. Semen's

'Zoologischc Forscl.ungsreiscn in Australien und dem Malayischen Archipel," 1897.

THE BRAIN IN THE EDENTATA. 285

There is much in this important memoir which calls for criticism, but at present I will

merely take cognizance of the references to Jlau/'s. In a future memoir I sluili discuss

some of the statements in reference to the Monotremata and Marsupialia, as well as

some of the more general questions, the consideration of which is precluded here by

limitations of space.

Several investigators have recorded the weight of the brain in various Edentates, the

most noteworthy contribution to this suliject being Max Weber's monograpii (Jam. cit.

p. 282).

If we sum up this literature we find tliat, apart from observations upon the general

form and size of the brain, it contains little information of sufficient exactness to be

of value to the comparative anatomist. Almost the whole of the data collected in the

memoirs concern the cerelnul cortex, and even with regard to this important region of

the brain we are provided with only the most meagre information, often very vaguely

expressed. Almost all writers are silent concerning the basal regions of the brain,

which are of especial interest in the lowlier mammals.

Heviewing the literature of the different families, we find that nothing is known of the

adult brain of Orycteropus, except such information as the examination of cranial casts

has provided. The brief notes of Pouchet and Gervais upon the brain of a foetal

Orycteropus add little, if anything, to our knowledge.

Concerning the Myrmecopliayidce, we have, in the recent memoir of Forbes and the

earlier contribution of Gervais, a very good account of the cerebral hemisphere of

MyrmecopJiaga, although the base of the hemisphere and the rest of the brain receive

very scanty treatment.

Practically nothing beyond the brief and imperfect notes and unsatisfactory figures of

Pouchet has hitherto been made known of the brain of Tamandua.

Por our knoAvledge of Ci/cloturm \yq are indebted mainly to Pouchet and the early

memoir of Tiedemann.

The knowledge of the brain in the Sloths is even more unsatisfactory, as no minute

description has yet been given of the brain in either Brudi/pus or CJioloepus.

Gervais' beautiful figures of cranial casts in these two orders have made us familiar

with the exact sliape and size of the brain, and the series of figures of Pouchet and the

more recent contriljution of Turner have given us a much fuller view of the brain in

this order than the earlier works of Tiedemann and Rapp conveyed. But even now

our knowledge of the brain in this family is very deficient, and I am able to supply

the required information only very imperfectly.

I have endeavoured to supplement and discuss as a whole the data concerning the

Armadillos, for which we are mainly indebted to the memoirs of Turner, Pouchet, and

Garrod, and which relate to all the genera except Priodon, our only knowledge of which

is derived from the figure of a cranial cast, which Gervais has contributed.

The interesting brain of ChlamdyopJioriis, concerning which Hyrtl published a few

notes, which were supplemented by a fuller descri^jtion by Pouchet, has been carefully

studied in a series of sections stained with carmine. This has enabled me to srive

SECOND SERIES. — ZOOLOGY, VOL. VII. 4-0

286 DE. G. ELLIOT SMITH ON

a mncli fuller and more accurate account of this peculiar brain than Pouchet has

provided.

Max Weber has recently contributed an admirably illustrated account of the brain in

Manis, which is a most valuable supplement to Pouchet's imperfect work I have been

able to add slightly to Weber's account, and upon comparative grounds have interpreted

certain features in a somewhat different manner.

The Ventral Surface of the Cerebrum.

The most convenient landmark with which to begin the description of a brain for the

purposes of accurate comparison is probably the optic chiasma. The optic nerve, taking

its origin from the eye lying in the orbit, enters the cranium and extends toward the

base of the brain at the situation wliere the brain-stem joins the cerebral hemispheres.

In Orycferopiis * this point is situated about midway between the cephalic and caudal

extremities of the brain, or, to be exact, 52 mm. behind the apex of the hemisphere

(which is formed by the olfactory bulb), and 56 mm. in front of the place where the

medulla oblongata merges into the spinal cord. (These measurements, as all the

figures given in this memoir, refer to material which had been kept in alcohol for

jirolonged periods.) The optic nerves enter into relationship with the base of the brain

at this mid-point, and effect an intercrossing of fibres, the oj^dc chiasma, from each side

of which a rounded bundle of fibres, the oj^fic trad, arches laterally, and with a slight

inclination backward, to disappear (at a distance of 6-5 mm. from the mesial plane)

under an overlapping fold of cerebral cortex, which we shall subsequently recognize as

part of the j^yi'/form lobe.

Por convenience of description we may regard the areas in front of the optic chiasma

as part of the cerebral hemisphere, and the parts behind it as the brain-stem.

Immediately in front of the optic chiasma, on each side of the mesial plane, we find

a flat depressed quadrilateral area of about 8 mm. diameter. This is called by different

writers a variety of names, of which loctts 2ic>'foratus {ant lens) is as convenient as any.

As I shall not refer to any other ferforated space, I may omit the qualifying

adjective. In front of the perforated space we find a large oval area of grey substance,

which is slightly raised above the surrounding regions. This is the tnherculum olfuc-

toriuiii. Its major axis, which is sagittal, measures 18 mm., and its maximum breadth

13 mm. It is not confined to the ventral surface, but also extends on to the mesial

surface of the hemisphere, and there presents a fusiform outline below the precom-

missural area. The lateral border of the iuherculum olfactorium is clearly defined by a

furrow in which a A-ery compact strand of nerve-fibres, which constitutes the olfuctonj

trad, is found. In a fresh bi^ain the pure white colour of the latter would present

a marked contrast to the brownish-grey colour of the olfactory tubercle. TJie tradus

olj^actoriiis is situated upon the surface of a cortical area, which we shall call the anterior

l}art of ihe, jjyriform lobe. This jiart of the pyriform lobe is visible along the lateral

* As practically nothing is known of the brain of Oryderopus, I describe it in some detail and point out the

features in other forms b}- contrast.

THE BRAIN Ii\ THE EDENTATA.

287

margin of the olfactory tract as a narrow band of grey substance with an irregular

tuberculated margin. The pyriforni lobe, the anterior part of which is formed by this

tuberculated worm-like process, will be found to expand posteriorly and form a large

rounded prominence, which is often known as the natiform eminence. This expanded

portion of the pyriform. lobe we may distinguish as the lobus injriformis posticus, to

distinguish it from the lohus pt/riformls aniiciis, which is merely the tapering cephalic

extremity of the same histological formation. These two parts of tlie pyriform lobe are

separated the one from the other by a depression, the vallecula S/jlvii, which extends

obliquely in a mesial direction toward the perforated space.

Fig. 1.

bulb, olfact.

lob. pyriform. ant

loc. perforat

lob. pyriform.

post.

nerv. III. .

pons Varol..

pyramid. -

ped. olfact.

■ tubercul. olfact.

• tract, olfact.

vail. Syl.

tract, opt.

crus cerebri

Corp. geaiculat. po6t^

■gangl. interped.

nerv. V.

•fiss. flocculi

■paraflocc. dors,

parafioco. veatr.

trapezium

medulla oblong.

Ventral surface of brain of Ofijcicropus. Xat. size.

The terms " lohus pynformis " and " tractm olfactorius " have been applied in a

sense slightly different from that which the majority of writers attach to them. This

attempt at a greater precision in description needs some sliglit explanation. It is

customary to restrict the term " lohus pijriformis" to that expanded posterior area of the

lobe (as we understand it) which is situated behind the vallecula S//lcii, and for which

the terms " natiform eminence," " hippocampal lobule," and many other variants of

these terms are regarded as alternative names.

The anterior tapering part of the same histological formation, which we haA^e already

40*

288

DR. G. ELLIOT SMITH ON

iucliuled in tlie pyi-iform lobe {lobus pyriformis anticns), is generally referred to as the

" tracfns olfactorlus." This confusion may be avoided if we restrict the term olfactory

tract to its literal meaning as the group of nerve-fibres lying on the surface of a cortical

area, Avhich. is the cephalic extension of the pyriform lobe. [To be strictly accurate we

should say that the lobiis pijriformis postictts is the greatly expanded caudal extension

of the lobtis 2^!/f'ifor7nis anticns, but as the name " pyriformis" is usually associated

exclusively with the former, I have spoken of extending it (the name) to the latter.]

I have deliberately avoided the use of the term " hippocanipal lobule," or any of

the many vai'iants of this term, because such expressions introduce a most undesirable

confusion with the true "hippocampus," a structure quite distinct from the pyriform

lobe, but one which in literature is frequently mistaken for it as a result of the

confusing nomenclature in common use. This is an interesting example of the

widespread misconception to which such loose nomenclature can lead in comparative

anatomy : for the student of the literatvxre x'elating to the fore-brain in Reptilia and

Dipnoi (more especially Burckhardt on Protopderiis) has had but too clear a demonstra-

tion of the utterly chaotic state of the morphology of the fore-brain which the confusion,

of pyriform lobe with hippocampus can produce. If we consider tlie base of the

hemisphere as a whole, it will be found to present a pyriform shape. It is broadest at

its posterior extremity, and contracts gradually as it extends forward, so that it passes

insensibly into the large rounded stalk of the huge olfactory bulb which caps the anterior

extremity of the heniispliere.

The hidhns olfactorius is a large conical cap of grey substance of about the size and

shape of a Albert nut. The contour of the ventral surface is not unlike the conventional

heart-shape, with the apex pointing forward. This surface is indented by a deep

Fis. 2.

cerebellum

Bss. prima

ped. olfact.

bulb. 9lfact.1

i fiss. flocculi

parafloco. dors.

medulla oblong.

lob. pyriform. ant. '

tract, olfact.

tnbercul. olfact.

Corp. geniculat. ant.;crus. : ,?°'^^, ■ parafiocc. veutr.

I cerebri area "arol. , *^

Corp. tegmenti flocculus

geniculat. post.

Left lutenil hurt'ace of biaiu of Uri/ctcio^m.s. .Xat. size.

The cerebral hemisphere has been separated from the rest, by cutting the jmictiou of the optic tbahimus

and corpus striatum so as to expose the Literal aspect of the thalamic aud mid-brain.

sagittal fissure which is placed nearer the lateral than the mesial border. This fissure

indents the whole thickness of the wall of the olfactory bulb, so that when we examine

THE BRAIN IN THE EDENTATA.

289

the large cavity or ventricle of the bulb we find a very prominent longitudinal ridge in

the floor, Avhich is tlie result of this indentation (fig. 19),

The olfactory bulb is connected with the rest of the licmisphere by a large rounded

peduncle, which is visible upon the base of the brain in the interval between the

tuberculum olfactorium and the buJbus olfactorms. Even in a view of the dorsal aspect

of the brain the peduncle is visible, because the apes of the cerebral cortex does not

overhxp it to so great an extent as in most mammals. On the lateral aspect of the

hemisphere the massive olfactory peduncle extends backward and becomes directly

continuous with the cephaUc extremity of the j^yriform lobe. The medullary covering

which whitens the surface of the peduncle converges to form the compact olfactory tract,

and immediately above this we find- the vermiform anterior pyriform lobe. The narrow

Fi-. 3.

■ - bulb, olfact.

—ped. olfact.

-lob. pyriform. ant.

tisa. rhinal.

. fiss. prima

— area A

'-^ area B

■■ area C

fis3. Beeunda

medulla oblong.

Doreiil surfuci-^ oi' ))raiii of Orjjcteropus. Nat. size.

Based on a pencil sketch by tlie late Rt. Hon. T. H. Huxley.

band of grey substance which constitutes this part of the pyriform lobe is deeply

constricted in many places, so that it appears to consist of a series of round knolis.

These knobs are so prominent that they produce correspondingly deep depressions on the

cranial wall, and hence we can readily recognize them in cranial casts. A beautiful

290 DE. G. ELLIOT SMITH ON

demonstration of this is givea Ijy Poucliet's figure of a cranial cast of Ori/cteropus*.

In a dorsal view of the actual brain the tuberculated lobtts 2}yi"iformis anticus is very

distinctly seen at the lateral border of the anterior part of the cerebral hemisphex*e

(fig. 3).

In the specimen of OrycteTopus which we have so far been considering, the upper

boundary of the pyriform lobe is very definitely indicated in its whole extent by a deep

and clearly-cut rhinal fissure, Avhich begins anterioidy in the cleft between the apex

of the hemisphere and the olfactory peduncle, and proceeds backward in a direction Avhich

is practically horizontal (fig. 2). The posterior half of the fissure descrilies a very slight

arc whose convexity is directed ventrally. Upon being traced backward the rhinal

fissure extends on to the caudal surface of the hemisphere and proceeds transversely

inward, as vre may observe in a view of the ventral surface of the brain (fig. 1). The

fissure ultimately reaches tlie mesial surface of the hemisphere and then ceases abruptly

(fig. 4). In the -whole of its course the fissure lies about midway between the upper and

lower surfaces of the hemisjihere.

The term ^ssitra rhhudis may be most conveniently employed to designate the whole

of this extensive fissure, as I have applied it in the above description, and not only to

the anterior part as Krueg uses it f . The anterior jmrt of the fissure, wdiich forms the

upper boundary of the lohus 'pyrxjormis anticus, may be distinguished as the fissura

rhinalis anterior, and for the posterior part of the fissure we may adopt Krueg's name

"Jissura rhinalis jiosterior." The term "rhinal fissure" may be used to apply to the

combination of these two fissures. The dee}) cleft between the olfactory peduncle and

the apex of the hemisphere is sometimes regarded as part of the rhinal fissure. If we

admit this, the rhinal fissure begins and ends on the mesial surface of the hemisphere in

Oryctero2n(>s (fig. 4).

In the brain Avhich I have hitherto been describing, the features of the extensive

undivided rhinal fissure were clearly defined in its whole extent, and presented an

exactly similar appearance in both hemispheres. But both of the brains in the Museum

of the lloyal College of Surgeons present a peculiarity in the disposition of the rhinal

fissure, in which, while they agree the one with the other in both hemispheres, both diff"er

from the type specimen Avhich we have been so far considering. This peculiarity consists

of a separation of the anterior from the posterior rhinal fissure. The anterior rhinal

fissure begins anteriorly in the ordinary manner, and forms the upper boundary of the

anterior jiyriform lobe in the whole of its extent, but then ceases without joining the

l^osterior rhinal fissure. The posterior rhinal fissure extends forward above the anterior

rhinal and pursues a course for some distance parallel to the anterior fissu.re. Thus the

cortex of the pyriform lobe is connected to the cortical area lying above the rhinal

fissure, now generally known as imllium, by a narrow process of cortex lying between

the overlapping extremities of the two parts of the rhinal fissure. This condition has

been somewhat schematically represented in fig. 5.

* G. Poucbet, op. cii., ' Journal de TAnatomie,' &c. torn. vi. pt. t. fig. 3.

t Julius Krueg, " L'eber die Furchen auf der Grosshirnrinde dor zonojjlaccntak'ii SiiugetLiere," Zeitschr. f.

wissensch. Zoologie, Bd. xxxiii. ISSU, p. 610.

THE BKAIN IN THE EDENTATA.

291

hippocamp. vestigia

ex.

Fig. 4.

psalterium dors.

I

Corp. /

callos.

bulb, olfact

I fiss. hippocampi

f^^ fascia dentata

-fiss. rhinal

• . , , ,, . , I '^ \ N fimbria

/ tubercul. olfact. | \ \_ \ \

Ilea, oiiact. commiss. ant. \ ,„. » .,

, '. ^ \lob. pynform.

psalterium ventr. \

tubercul. hippocampi

comm habenuL

Corp. pineale

a fiss. prima

i =°!'P- ,' cerebellum

I quadrigem.

/ fisa. secunda

foramen Monr.

"ventr. IV.

vel. medullar©

pons Varol.

commiss. moU. ; ( I

Corp. mammill. | gangl. interped.

aquaeduct. Syl.

Mesial surface of the brain of Orycteroims, exposed by mesial sagittal section. Xat. size.

The hemisphere above separated from the rest of the brain, and bdo^r in part attached to the brain-stem.

Fig. .5.

fiss. rhinal. ant. y ^

bulb, olfact. : ^ ; :

■ lob. pyriform. i

fiss. rhinal. post.

tract, olfact.

tubercul. olfact.

lob. pyriform. post.

Scheme of the lateral aspect of the cerebral hemisphere of Oryctcroinis, to show a variation

in tlie arrangement of its fissures.

292 DK. G. ELLIOT SMITH ON

The I'liinal fissure thus forms a very clear boundary in the whole extent of the lateral

and caudal extremities of the hemisiohere between the pyriform lobe and the histo-

logically and morphologically distinct area of pallium. But ujjon the mesial surface of

the hemisphere (fig. 4) the upper margin of the pyriform lobe blends with the pallium

without any clear external indication of the line of junction. In this part of the

liemisphere the jiyriforra lobe extends around the postero-inferior angle, and is partly

limited in front by the loAver joart of an arcuate cleft — the ^/issar a hippocampi. But

below the hippocampal fissure the pyriform lobe seems to be continuous with a peculiar

oval body, which, for reasons to be subsequently explained, will be distinguished as the

" tuherculuni hippocampi " or " hippocampal tubercle." The height to which the lobiis

pyriformis extends upon the mesial surface is indicated by the indentatiou \\\)o\\. the

posterior margin of the hemisphere, which is the termination of the rhinal fissure (fig. 4).

If Ave compare these basal regions of the cerebral hemisphei"e of Orycteropiis with

those of the Great Ant-eater, Ilyrmecophaga juhala, which in size and general mode of

life presents some resemblance to the African representative {Orycteropiis), we find a

general agreement bstween the two forms, but at the same time a number of interesting

points of diff"erencc. Although ihe figures and descriptions of Forbes * have added

much in clearness and exactness to the earlier observations of Gervais t, we still lack a

faithfid representation of these basal regions of the hemisphere of Myrmecophaga.

The bulhus olfactorius is relatively almost as large as that of Orycteropus, but it is not

so pointed, nor is it indented by any fissure such as we have seen in the latter. It is

also attached to the hemisphere by a large rounded peduncle, whose relations are

analogous in the two forms. The luherculum oJfactoriiim is not so elongated as it is in

the Aard-vark {Orycteropus), and presents a somewhat quadrilateral form. The tractus

olfactorius presents the same general features, but in Myrmecovhaga ends in a prominent

elliptical nodule, which is situated in the vallecula Sylvii immediately in front of the

emineutia natlformis and at the lateral margin of the locus perforatns (fig. 6). This

Fig. 6.

loc. perforst.

nerv. II tnbercal.' ol/act,

tract, opt. ,■ ^ ,, .

\ : . . tract, olfact.

VJ, • y » -- Alob. prrifonn,

rXmf^imlfmK /fsnoia dcntata

f^^'^^ll/ Irl /""f- "'■Mill.

m\Wk//////if """ °°"''"

%vyJ^U-tpfJ gaogl. interped.

Parh of tlie ventral surface of the brain of Myrmecojihaga juhata. Sligbtlj' reduced.

little nodule, which has been indicated in the figures by the name tuherculum tractus

olfactorii, has been described in the Hedgehog {Erinaceus) by Ganser $, and is found in

* Op. cii. Proc. Zool. Soc. London, 1882. t Op. cit., Nouvelles Archives, t. v.

t S. Ganser, " Uebcr das Gcbiru des Mauhvurfs," ilorphologiscbes Jahrbuch, Ed. vii. 1882.

THE BKAIN IX THE EDENTATA.

293

a well-developed form in Tamandua (fig. 9), the Dasypodidte and Bradypodidce, and

possibly in other representatis^es of the Edentata. A very well-defined fissura rJmiaUs

is present to indicate the upj)er bouudary of the pyrit'orm lobe, but it differs very

distinctly from that of Orycteropus in that the posterior rhinal fissure joins the anterior

rhinal, with which it is continuous, at an angle (fig. 7), wliile the anterior rhinal fissure

Fia

bulb, olfact.

ped. olfact.

fiss. rhinal. ant

tnbercul.

olfact.

paraflocc.

pons Varol.

lob. pyrifonn. S

fiss. rhinal. post

Lateral aspect of a braiu oi 21yrmecophaya julattt.

S, Fossa Sylvii.

Very slightly reduced.

is still horizontal ; the posterior rhinal inclines obliquely downward and backward, so

that it reaches the ventral margin at a point about midway between the vallecula Sylvii

and the posterior extremity of the hemisphere ; it then curves inward upon the inferior

surface, and ultimately ends upon the jDostero-inferior part of the mesial surface at a

point just behind the lower part of the hippocampal fissure. This mode of termination

of the rhinal fissiu^e in Myrmecophaga has l)een well figured by Forbes *, and presents

a close analogy to the disj)Osition which is rejiresented in Tamandua in this memoir

(fig. 10). The rhinal fissure in Tamandua (fig. 8) presents a less acute bend than is the

Fip

^lob. ant.

y ! area A

area 6

^ cerebellum

; paraflocc.

bulb ■ olfftpt ■ ' '""> I flocculus

pulD. oaaot.jj.^gj olfact.; Pjnform.;

fiss. rhinal. pons Varol.

Lateral surface of brain of Tanniitdua titradacff/h(. Nat. size.

case in the larger Ant-eater, and as a result it approaches much nearer the posterior

margin of the hemisphere, but otherwise its disposition closely agrees with that of

* Op. dt. Proc. Zool t^oc. London, 1882, fij;. 4.

SECOND SERIES. — ZOOLOGY, VOL. VII. 41

294

DE. G. ELLIOT SMITH ON

Myrmecoi^haga. In both representatives of the Myrmecopliacjidce the rhiual fissure is

nearer the base_.of the In-ain than it is in Orijcteropus, so that in a view of the ventral

surface practically the whole of the fissure is visible (tig. 9).

Fis. 9.

fiss. rhinal. '

loc. perforat

tract, opt.

Corp. mammill.-

nerv.V.

trapezium

bulb, olfact.

..ped. olfact.

-lob. pyrifonn.

tuber, olfact.

■ nerv. II.

tuber, tract, olfact.

infundib.

crus cerebri

pons Varoi.

.|;>-~ parafloec.

.. ^flocculus

nerv. VIII.

pyramid.

Ventral surface of brain of Tamandua. Nat. size.

It follows from the above remarks that the shape of the pyriform lobe is very different

in the American Ant-eaters, and esjiecially the Great Ant-eater, from that which we

have found in the African Aard-vark. Thus in 3Iyrmecoplictga, and to a less degree in

Tamandua, there is a very distinct flexure in the pyriform lobe which is wanting in

Orycferopus. The pyriform lobe is besides relatively smaller in the American forms.

In these brains also the anterior limit of the pyriform lobe upon the mesial surface

of the brain is more distinct, because the peculiar hijapocampal tubercle which we

found in Orycteroptts is lacking in the Ilyrmecophagidce, and the hippocampal fissure, as

a consequence, extends much lower (fig. 10). As a result of the flexure of the pyriform

lobe in Ilyrmecopliaga, the vallecula Sylvii is deepened and a number of deep clefts or

puckerings indent the surface of the pyriform lobe in this region. They are probably

mere mechanical results of the bending (fig. 7).

In Tamandua the tuhercuhmi olfactorium presents the same quadrilateral shape which

we noted in Ilyrmecophaga. The olfactory bulb is relatively smaller than it is in the

larger brains, and its peduncle is not so prominent because its dorsal surface is completely

hidden by the anterior pole of the hemisphere.

My knowledge of tlie conformation of the brain in the small arboreal Ant-eater

Cycloturus has, in the al)sence of any material, been derived mainly from the imperfect

notes and illustrations which Pouchet (op. cit.) has contributed, and the even less

complete observations of Tiedemann {op. cit.) and Gervais {op. cit.). It is not clear

from Pouchet's work whether any rhinal fisstire is present in the small arboreal Ant-eater.

He says in the text that the brain of Cycloturus (which he calls Dionyx) is smooth,

and he does not represent a rhinal fissure in his figure. But since he does not represent

THE BRAIN IN THE EDENl'ATA.

295

the clearly defined rliiual fissure in Tamandua, tlie non-delineation of a corresponding

fissvire in his figure of Cycloturus cannot he regarded as any indication of its absence.

The illustrations which the earlier observers (Tiederaann, Leuret, and Rapp) have given

of the brain in the Sloths convey practically no information concerning those regions of the

brain which we have just been considering in the Aard-vark and Ant-eaters, and the figm-es

which Pouchet [op. cit.) has given of the Brady podiclce do not represent even a feature so

fundamental as the rhinal fissure. Professor Turner's representation * of the brain of

Choloepns Hoffmanni, so far as I am aware, is the only figure wiiich represents this feature

Fig. 10.

psalterium dors.

psalterium ventr. /

'^corp. callos. /

euJc. Umitans pallii

bulb, olfact.

fimbria

hjppocamp. inversus

fascia dentata

-fiss. hippocampi

fisB. rhinal.

ped. olfact. -' ;

taberoul. olfact. i

area praeoommiss. >

\ tract, opt.

lob. pyriform.

i_ tuber, tr^ot. olfact.

.commiss. ant.

lamiua terminalis

Mesial surface of right central licmisphere of Tamancliut. Enlarged 2. diam.

in the brain of the Sloths. Of the two brains of Bradypus tridactylus at my disposal,

one had almost reached the adult state, whereas the other was much younger, since it was

taken from an animal measuring only 34 cm. from the nose to the anus. In the former

the anterior rhinal fissure begins in the ordinary manner and extends obliquely upward

and backward, and when it reaches a point midway between the anterior and posterior

poles of the hemisphere it joins the posterior rhinal fissure alino.st at a right angle (fig. 11).

The posterior rhinal fissure forms an arc, the postei"ior extremity of which crosses the

posterior border of the hemisphere at about the same horizontal level as the cephalic

extremity of the anterior rhinal fissure.

In the younger brain the two parts of the rhinal fissure approximate much more

closely to the horizontal, so that their angle of junction is very obtuse. The posterior

rhinal fissure is represented merely by a very shallow furrow.

In Cholcepus didactylus and, jvidging from Turner's figure [op. cit.), also Choloepiis

Hoffmanni, the angle of meeting of the two parts of the rhinal fissure is quite as obtuse

* AV. Turner, op. cit., Journal of Anatomy and Physiologj-, vol, xxv.

41*

296

DR. G. ELLIOT SMITH ON

as it is in the younger Bradjipiis. The anterior rhinal fissure is very ohlique, hut the

posterior rhinal fissure is almost horizontal (tig. 12).

The conformation of the base of the brain in the Bradypodidce is so like that of

Tamandua that it is unnecessary to give special illustrations, nor is it requisite to describe

these features in detail. The general shape of the base of the brain in Brady pus is very

bulb, olfaot.

tnbercnl.

olfact.

fiss. rhinal, paraflooc.

lob. pyriform.

Lateral surface of brain of lii-ddiiiinn ilnlitclijlus. Nat. size.

bulb, olfact...

fisa. rhinal.

paraBocc. dors.

. paraflooc. ventr.

tract, olfact

• nerv.V.

■ lob. pyriform.

tnbercoL olfact.

: flocculns

pons Varol.

trapeziom

. pyramid.

Lateral surface of Imiin of CholceiiHs didactj/lvs-. Slif;htly enlarged.

much like that of Tamcmdua (fig. 9), but in the former more of the pallium is visible along

the lateral margin of the anterior part of the pyriform than is the case in the Ant-eater.

This means that the proportion of pyriform lobe to iiallium is less in the Sloth than in the

partially arboreal Ant-eater. In Cholcepns the base of the brain appears to be relatively

broader than it is in B)-adijpns, but otherwise it presents a close resemblance.

In none of the Armadillos (with the possilile exception of Priodon) do we find a

complete rhinal fissure. Nothing is known of the brain of Priodon, except such

information as we can gather from the examination of cranial casts, such as Gervais has

represented {op. cit. pi. ii. fig. 12). But it is quite possible and even probable that in

such a large brain a complete rhinal fissure will be found, because we find among

mammals that an increase in bodily dimensions is accompanied by an increased extent

THE BRAIN IN THE EDENTATA. 297

of pallium : in other words, an increasing disproportion between the sizes of the pallium

and the pyriform lobe. It is such inequalities in the rate of growth of these funda-

mentally distinct cortical areas that give rise in all probability to the rhinal fissure.

In Chlami/dophonis there is uo rhinal fissure whatever, but in all the other Dasypodidae

there are small anterior and generally also posterior rhinal fissures, w^hich are separated

by a varying interval in different genera.

In Tatusia noremcincta, two specimens of which I have had the opportunity of ex-

amining, we see the arrangement of these fissures in a typical manner. A short anterior

rhinal fissure begins in the cleft between the olfactory bulb and the apex of the pallium,

and extends horizontally backward for less than a third of the length of the hemisphere.

A posterior rhinal fissure, which is very shallow, extends from just below the middle

of the posterior border of the hemisphere and passes forward for less than a third of

the length of the hemisphere. In the figure which Pouchet gives of a young Tatusia

{op. cit. pi. vi. fig. 1), these fissures are only indicated very faintly. As both of the

specimens which I examined were distorted, I have modified this figure of Pouchet so

as to indicate the features present in my specimens (fig. 13).

Fig. 13.

fiss. rhinal. post.

fiss. rhinal. ant. o

...paraflooc.

bulb, olfact. !

tubercul. olfact. \

lob. pyriform.

Scheme of lateral surface of brain of Tatuf'ui [Hha.

In the pallium, just above the wide gap between the anterior and the posterior

rhinal fissures, we find a short oblique fissure which may be distinguished as 0.

Fig. U.

0 S

■ \ fiss. rhinal. post.

fiss. rhinal. ant.

,j)arafloco.

bulb, olfact. ; ; '"''• pyriform. flocculus

: : tuBer. tract, olfact.

. ,. ,'f . tubercul. olfact.

tract, olfact.

Lateral surface of brain of U'lsiqu's si.rcinrttia. Nat. size.

In Dasypus sea'cinctus (fig. 14) and Basi/pm vUIosks we find practically the same

arrangement of the rhinal fissures, with the difi'ereace that the more extensive posterior

rhinal fissure enters into uninterrupted continuity with the pallial fissure /3.

298 DK- Gr. ELLIOT SMITH ON

In the figures which Turner (oj). (?//•)' Gervais (ojj. cit.), and Pouchet {op. cit.) give

of the hrain of Dasypus we find the same ai-rangement as I have just described in my

specimens.

In Tolijpentes and Xemirm we find essentially the same arrangement, hut the caudal

extremity of tlie posterior rhinal fi.ssure may fail in both these forms. Garrod {op. cit.

Proc. Zool. Soc. London, 1878) gives figures of the brain in both of these Armadillos.

In all of the Armadillos the olfactory bulb and all the parts of the brain which are

intimately associated with it reach relatively enormous dimensions. Visual acuteness is

a matter of subsidiary importance to animals which burrow in the ground for their means

of subsistence, and hence the importance of a sense like that of smell, which enables

these animals to detect objects which they cannot see, becomes considerably enhanced.

Thus the macrosmatism which characterizes all mammals, except those whose pallium

has become sufficiently specialized to be something more than a mere sensorium,

becomes very much exaggerated in these burrowers, who are guided in most of their

pursuits mainly by olfactory impressions.

The large olfactory bulb varies considerably in shape in the different genera of this

family. As the soft bulb is more liable to distortion than any other part of the brain,

it is safer to rely upon the evidence of cranial casts than upon the examination of actual

specimens when these have not been seen in the fresh state. Gervais has fortunately

provided us with a complete series of cranial casts of the Dasypodidae {op. cit. pi. ii.).

From the shape of the cranial casts, as well as from all the figures of Gervais, Pouchet,

Turner, and Garrod, and from my own observations, it is evident that the large olfactory

bulbs of both species of Dasypus and also of Tohjpeutes assume a conical shape such

as I have already had occasion to note in the Ant-eaters, Slotlis, and Aard-varks. This

form of bulb is also found in the extinct Ground-Sloths Mi/lodon, Scelidotherium, and

probably also in Ilegatherium. It is equally found in the great extinct ArmadUlos

Glyptodon (in which the olfactory bulb assumes enormous proportions), and probably

Eutatus. In Xenurus and Tutusia the projection of the olfactory bull)s is still a

feature of the brain, hut it is not so developed as it is in Dasypus. There is a certain

amount of antero-posterior flattening of the lower part of the bulb in these forms.

In Chlamijdoplwrus there is a very distinct antero-posterior flattening of the bulb, just

as there is in the larger brain oi' tlie Pangolin {Manis). But the shape of the olfactory

bulb is a matter of slight importance.

We can better appreciate the high degree of macrosmatism of the Armadillos if we

compare their brains with that of the little arboi-eal Ant-eater Ci/oloturus, the shape and

size of which is admirably shown by the figures of Tiedemann, Pouchet, and Gervais.

"When Ci/cloturus relinquishes a terrestrial life, such as its near relative Mi/nnecophaya

leads, the olfactory sense diminishes in importance, and hence we have a reduction in

the size of the olfactory bulbs and the rest of the apparatus pertaining to the function

of smell.

In the brain of tlie Armadillos the predomijiance of the sense of smell manifests itself

in other ways in addition to its direct effect upon the olfactory bulb. The tnberculwni

olfuctoriimi is uniformly very large and of relatively greater prominence than it is in the

THE BHALX JX THE EDEXTATA.

299

Sloths and smaller Aut-eaters. The i)yriform lohe also becomes relatively much

laro-er, and frequently constitutes as much as half the lateral wall of the hemisphere.

In spite of this increase in size, the posterior part of the pyriform lobe does not form such

a prominent projection (" natiform eminence ") upon the base of the brain as it does in

the Ant-eaters. In the latter the growth of the pallium contributes toward the thrusting

down, as it were, of the posterior part of the pyriform lobe.

In most of the Armadillos the pyriform lobe does not project downward to a much

lower level than the tuberciUnm olfactonum, and in the peculiar little distorted brain of

Chalmycloj)lion(s the pyriform lobe does not descend nearly as low as the ftibercultmi

olfacforium, which is much the most dependeat part of the hemisphere (figure 15).

bulb. oltMt. lob, pyritorm.

tabor:iul. olfact.

Lateral surface of brain of Chlamtjihphorus truncaius. Enlarged 2 diam.

■v. Deep groove formed b}- semicircular canals upon base of hemisphere.

In Chlamijdophorns there is no rhinal fissure, but histological examination demonstrates

that the junction of pyriform lobe and pallium is placed very high upon the lateral wall,

so that the pyriform lobe forms more than half of this aspect of the hemisphere. It is

unnecessary to do more than refer to the peculiar, flattened, cake-like, sessile olfactory

bulb and the elliptical tuherculum olfactorinm wdiose major axis is transverse.

The receding surface of the pyriform lol^e in Chhimndophoms is seen to even better

advantage in a view of the mesial surface of the hemisphere (figure 16). This, as well as

Fig. 10.

hippocamp. vestigia

Corp. oailoa. flex, liippocampi

bulb, olfact

psalterium

ventr.

fiss. hippocampi

fascia dentata

oommiss ant

tubercul. olfact.

area praecommisB.

fimbria

Mesial surface of right cerebral hemisphere of Chhiiiii/diqiJ'oriis. Enlarged 3 diam.

.r. As in fig. 15.

the preceding figure, shows part of the peculiar depression (a;) which we find upon the

ventral receding surface of the pyriform lobe, and to which Hyrtl {oj). cit.) and Pouchet

300 DR. G. ELLIOT SMITH ON

{op. cit.) have alroady called attention as resulting from the upAvard projection of the

bony semicircular canals in the periotic hone. Pouchet has already given a ligure of tlie

ventral surface of the brain, which indicates tlie situation of this depi'ession.

The imperfect descriptions of the brain of Manis which Pouchet {op. cit.) and Gervais

{op. cit.) had given have recently been supplemented by the concise and well-illustrated

description by Mas Weber {op. cit.). I have been able to confirm the accuracy of his

brief description by the examination of two specimens of this genu.s. The basal regions

of the hemisphere present in a typical manner the characteristic features which we have

met in all the other forms. The base of the brain is very broad. The large olfactory

bulb forms a thick buffer-like pad upon the flattened ceplialic extremity of the

hemisj^here. The large tuberculum olfactorium presents an almost circular outline.

The posterior part of the pyriform lobe is most markedly dependent, and descends to a

much lower level than the rest of the hemisphere. This feature is much more pro-

noimced than it is in any other individual in this heterogeneous group of mammals, and

is probably a result of the obvious restriction to tin: expausiou of the brain in the longi-

tudinal direction.

The rhinal fissure is interrupted in a manner which suggests an analogy to the

arrangement in the Armadillos. Tiiere is a very short horizontal anterior rhinal fissure,

which is quite independent of the posterior rhinal fissure. The latter begins at the

posterior margin of the hemisphere and arches forward, but just before reaching the

anterior rhinal fissure it extends up\^ard into continuity with a pallial fissure, in a manner

not unlike the posterior rhinal fissure in Dasyj^us.

The fundamental features of the regions of the base of the brain which we have just been

considering vary within relatively narrow limits in the Mammalia, although both Mono-

tremes exhibit features in common which readilv distino;uish them from all other

mammals. Such variations as we have found among the different representatives of this

order are characteristic of the changes which the basal region of the hemisphere undergoes

in the wider range of the Mammalia generally, and are in the main associated witli the

habits of life rather than witli the systemic position of the individuals. For we find

among other mammalian orders, more especially the Marsuj)ialia, Insectivora, Kodentia,

Carnivora, and Ungulata, parallel modifications Avhich indicate the more or less direct

causal relationship to the mode of life. All the areas which we have been considering

are intimately associated with the olfactory apparatus, and, Avhatever other functions

they may subserve, there can be no question that tlieir predominant r61e is to constitute

a receptive area for incoming impulses of smell. The importance of the sense of

smell varies considerably in the different members of this order, although in all it reaches

a very high degree of acuteness, as the great development of the olfactory bulb and its

associated cortical areas demonstrates. But in this macrosmatism the Edentata are like all

other lowly-organized mammals, in which the sense of smell has a larger function

than in higher mammals, in which an intelligence dispenses with the necessity of any

such predominant and guiding sense as the impressions of smell convey.

In Edentates like (Jvycteropus and the Dasypodiilce, which S])end their Jives mainly in

digging and bru-roA^iug in the ground foi' t)bjects as to the position of which the sense of

THE BKAIN IN THE EDENTATA. 301

smell is the main determinant, it is not surprising to find that the olfactory areas of

the In-ain reach a relatively larger development than in the arboreal Bradyjiodida' and

Cycloturiis, in \yliich the smell-sense is not of such vital importance. And in such

a form as Chlamydophorus, which lives mainly underground and depends to a very

slight degree upon its feeble visual organs, it is natural that the importance of the

olfactory ajiparatus should be still further enhanced, as finds expression in a relatively

enormous olfactory bulb and tuherculimi olf actor iitm, and a pyriform lobe which includes

more than half the lateral sui'face of the cerebral hemisphere.

In a short memoir upon tbe basal regions of the hemisphere, Gustav Retzius last year

called attcjition to certain features of the pyriform lobe and the adjoining areas in some

Edentates, among other mammals *. He makes special mention of the little " tubercle

of the external olfactory tract " in Marsupials and Edentates. He dignifies this little

body Avith the name (jyrus iufermedms rluueiicephuli (p. 107), but although he carefully

describes its situation, he does not give us any information concerning its structiu'e.

It will prove a source of considerable confusion if the term " gyrus " is applied to such

structures as tliis, involving as it does a considerable distortion of the generally accepted

idea of the meaning of this term. Retzius goes on to state that in the same animals

{Bidelphys, Ilacroptis, Myrmecoplmgu, Basypus among others) two or three sagittal

" gyri " are found behind the "gyrus intermedins." He calls these the "gyrus lunarls '*

and " gyj-usambiens {medialis and laterulis),'" in conformity with a nomenclature he had

previously apialied to the human brain f.

He further mentions that in the Insectivora {Erinaceus) there Is a very large "gyrus

lunaris " and a " gyrus ambiens.'"

Retzius does not make any mention of the fact that, in Erinaceus and many of the

Edentates, the fascia dentata (as we shall explain subsequently) extends on to the base

of the brain in the region of his " gyrus lunaris.'' Its relation to the latter structure

is well shown in the figure of the base of the brain in MyrmecopUaga (fig. 6).

The Cerebral Commissures.

In all vertebrates, series of nerve-fibres proceed from one cerebral hemisphere to the

other, and serve to bring into functional association brain areas which are otherwise

quite separate the one from the other. These fibres, whether they connect strictly

homologous areas or constitute a symmetrical bond between heterologous parts of the

two hemispheres, are generally known under the comprehensive title of " commissures."

In all excej)t the lowliest vertebrates there are two compact and \Aell-defined bu.ndles

of these crossing fibres forming ventral and dorsal commissures of the cerebral hemisphere.

Within the class of mammals the constitution of these two commissures becomes rearranged

in order to more readily accommodate the enormously increasing number of fibres which

* Gustav Eetzius, " Zur Kenntuis der Wiiiduugen der Riechhirns,"' Verhandl. Anat. Gesellsch. 1897, p. 10.5

et seq.

t Gustav Eetzius, ' Das Menschenhirn,' 1896.

SECOND series. — ZOOLOGY, VOL. VII. 42

302 DR. a. ELLIOT SMITH ON

are proceeding from that essentially mammalian cortical area, the pallium. In all

mammals except the Monotremata and Marsupialia (in which the pallial fibres cross the

mesial plane in the veiitral commissurel a large and increasing proportion of these pallial

fibres invade the dorsal commissure nnd form the corpus callosum. When we remember

that this structure has been acquired in its jii-esent form within the mammalian class,

we naturally turn with great interest to the examination of the commissiues in such an

enigmatical order of mammals as the Edentata.

Pouchet says * that the Edentates, considered as a whole, present a remarkable

diminution in the size of the corpus callosum. He says that in a young Choloejjns, which

was 19 cm. long, the corpus callosum was 7"5 mm. long and 0'5 mm. thick. la the

specimen of Cholcppns Hoffmanni which Turner figures t the corpus callosum is repre-

sented as being 11 mm. long and 1 mm. thick in a hemisphere whose maximum length

(without the olfactory liulb) is 8G mm.

In Elower's memoir there is an enlarged figure of the mesial surface of the brain of a

Choloppus d/df/cti/lns J, but unfortiinately the degree of magnification is not indicated. In

a hemisphere 70 mm. long, he represents a corpus callosum 23 mm. long and 2-8 mm.

thick. Judging fi-om the average dimensions of the adiilt hemisphere of Cholcejms, these

measurements are probably about twice the actual size of the objects. In my specimen

of Cholcepns didactyhis (which had been in alcohol for some years) the cerebral hemi-

sphere is barely 35 mm. long, and the corpus callosum measures 10'75 mm. loug and

I mm. thick.

We may safely conclude that the corpus callosum in the adult Two-toed Sloth is about

II mm. long and about 1 mm. thick. We cannot speak with the same degree of certainty

of the measurements in Bradyptis, because there is no information upon the subject in

the past records, and my only specimen available for measurement is not fully grown.

In the bi-ain of Bradypus tridactyliis which Professor Max Weber generously gave me,

the cerebral hemisphere is 26 mm. long, and possesses a corpus callosum which is 6"75

mm. long, and 1 mm. thick. In the adult brain the cerebral hemisphere attains a length

of about 32 mm. In this young Three-toed Slotli we have a corpus callosum which is

much shorter, both absolutely and relatively (to the length of the hemisphere), than is the

case in the Two-toed Sloth, but this shortness is compensated by a greater thickness, for in

this small brain of Bi'adypus the corpus callosum has already attained to the same

thickness which it readies in the much larger brain of the adult Clwloepns.

Poiicbet §, after describing the corpus callosum in tlie Sloths, proceeds to descril^e

that of the Ant-eaters. He says that in Cycloiurm aud Myrmecophaga it presents similar

features to that of the Sloths.

Tliis is a very loose and utterly misleading statement, for, as we shall see subsequently,

there is a very marked contrast between the features presented by the two families in

this respect. He gives the measurements of the corpus callosum in Myrmecophaga as

* Op. at., Journal de rAuatomie et de la Physiol, tm. vi. p. 308 et seq.

t Turner, o^<. cit., Journal of Anatomy and Physiology, vol. xxv. fig. 15.

X Flower, 0^1. cit., Pbil. Trans. 18(55, pi. xxxvii. fig. 5.

§ Oj,. at. p. 308.;

THE BK.AIN IN THE EDENTATA. 303

2G mm. in lengtli aud 2'5 mm. iii thickness. The corjjus callosum in tlie specimen

which Forbes figures is about the same length, but not quite so thick. The cerebral

liemisjihere in Ilijrmecophaga is usually about 54 mm. long, so that the corjnis callosum

is almost half tlie lengtli of the hemisphere.

In a specimen of Tamaudua, whose hemisjjhere is 34 mm. long, the corpus callosum

increases 14 mm. in length, and its narrowest part 1 mm. in thickness.

Pouchet * rejjresents the mesial surface of tlie cerebral hemisphere of a Cyclutaras, the

corpus callosum of which is very narrow and 6-5 mm. long, the hemisphere itself being

17 mm. long.

Thus we see that in the brains of the ]\Iyrmeco2)hagidse the corpus callosum is rela-

tively shorter in proportion as the animal is smaller, the corpus callosum measuring

respectively 48 per cent., 41 per cent., and 38 per cent, of the length of the hemisphere

in the three genera.

In all the Armadillos the corpus callosum is very small. Pouchet describes the

corpns callosum in a young Dasypus, whose cerebral hemisj)here is about 23 mm. long,

as being 0 mm. long and 1 mm. thick. Turner represents f in Dasyijus sescinct us the

cerebral hemisphere 30 mm. long, possessing a corpus callosum 6 mm. long aud 1 mm.

thick. lu the brain of Xenitrus, the cerebral hemisphere of which is 25 mm. long, we

tind a corpus callosum measuring o mm. in length and barely 1 mm. in thickness (in a

specimen preserved in alcohol). In ToUjpeutes the proportion is about the same. In a

cerebral hemisphere of Chlamydophorus, 11-5 mm. in length, we find a diminutive corpus

callosum of 2-25 mm. length and about '25 mm. thickness.

In all the xirmadillos, in spite of the small dimensions of the cerebral hemisphere, the

proportion between the lengths of the corpus callosum and the hemisphere is much

smaller than it is in the Sloths, and, a fortiori, than in the Ant-eaters.

In his figures of the brains of a Ilauis, Max Weber represents J a corpus callosum

G mm. long and 1'5 mm. thick in a hemisphere whose maximum length is 24 mm.

Pouchet represents ^ a corpus callosum 4'5 mm. ioug aud 0 75 mm. thick in the brain

of a young Manis, the hemisphere of which is 20 mm. long. In a cerebral hemisphere

of the same length as Weber's specimen I have found a corpus callosum 6 mm. long,

but barely 1 mm. thick. The disparity between these measurements of the thickness is

probably explained by the fact that Max Weber has not figured the supracallosal vestige

of the hippocampus, but represented it, together with the corpus callosum, as one

structure.

In Orycteropus I have found that the corpus callosum measures 21 mm. in length and

2 mm. in thickness in a hemisphere whose maximum length is 60 mm.

Although the corpus callosum becomes reduced in some families, especially in the

Armadillos, to very diminutive proportions, it is very misleading to state as a general rule

that the corpus callosum is small in the Edentata. To appreciate the full significance

* Op. fit. pi. iv. fig. 4.

t O^). cit. vol. XXV. fig. 13.

J Max Weber, o^j. cit. tab. ix. fig. 69.

§ Pouchet, 0/1. cit. pi. iv. fig. 10.

42*

304. Dll. G. ELLIOT SMITH ON

of the evidence to be gained by a study of the cerebral commissures, it is of much greater

impoi'tance to investigate their constitution and morphology than to judge them on a

purely quantitative basis.

In separating the two cerebral hemispheres the one from the other by means of a

mesial sagittal section, we cut throvigh the large white masses of the cerebral commis-

sures, which will be seen to consist of a small ovoid ventral commissure and a large

elongated dorsal commissure of a peculiar shajie. This dorsal commissure in Orycteropus

is composed of two divaricated limbs, which meet and fuse posteriorly. The larger dorsal

limb is the corpus callosum. Arching downward and backward from the ventral

surface of the caudal extremity of the coi'pus callosum, there is to be found a peculiarly

modified cortical area known as the hippocampus. The greater part of this peculiar

structure is submerged below the general level of the cortex, and its position is indicated

upon the surface by the hippocampal fissure. The cephalic margin of the hippocampus

is fringed by a band of white fibres — which is known either as fimbria or forma- — and

which is plainly visible upon the mesial surface of the hemisphere.

After these preliminary remarks we are in a position to ajjpreciate the features of the

cerebral commissures.

If we examine the mesial surface of the brain of Orycteropus which is exposed by a

mesial sagittal section (fig. 4, p. 291), we find the lamina terminalis extending obliquely

upward and forward from the oj)tic chiasma to reach the ventral or anterior commissure,

which consists of a large mass of transverse fibres presenting an oval outline in section

and measuring 4-5 mm. by 3"5 mm. Proin the dorsal aspect of the ventral commissure

the upper part of the lamina terminalis proceeds obliquely backward and uj)ward to the

inferior extremity of the ventral limb of the great bilaminar dorsal commissure. The

ventral limb of this dorsal commissure consists of fibres which are proceeding from

the hippocampus of one hemisphere through the fornix to the other hemisphere, and it

is custoniaiT to call these crossing fibres of the fornix the psaltcrimn *, from a fancied

resemblance in the arrangement of their homoloo-ues in man to a stringed instrument.

The psalterium in Orycteropms consists of a large ventral fusiform mass of fibres, which

form the psalterium ventrale, and a slightly narrower upper part, the psalterium dorsale,

placed immediately below the dorsal limb of the great commissure, which latter is best

known by the designation corpus callosum. The psalterium dorsale joins the caudal

extremity of the corpus callosum, which consists of a large rounded mass of fibres

known as the spleninm. The corpus callosum is a larger structure than the psalterium,

and, unlike the latter, is of fairly uniform thickness, except at its cephalic and caudal

extremities, which are thicker than the rest of the commissure. It is placed obliquely,

and its posterior part is parallel to fhe psalterium dorsale; h\xt n^ the psalterium ventrale

l)ends downward toward the ventral or anterior commissure, a triangular interval is left

l^etAveen the j)salterium and corpus callosum. This interval is filled by a mass of grey

substance which will be subsequently described as the corpus pai-acommissurale, and

which in part represents the septum lucidiim of human anatomy.

* FsnJtc)-iuin,^lifr(i, = coiniiiissur(t forn(cis.=^commis^Hrit hi/ipocaiii/ii.

THE BRAIN IX THE EDENTATA. 305

If we compare the commissures iu O/'i/cterojms \Yith those of Ilyrinecophacia, we find

that the ventral (anterior) commissure is approximately of the same size or even slightly

smaller in Ilyrmecophaga, hut the dorsal commissure presents a marked contrast. The

fsalterinm is much longer and more markedly attenuated than it is in the African

genus, while the corpus callosum is greater, more especially in length, and more nearly

horizontal than is the case in Orycteropus.

The anterior commissure in a representative of the latter genus raeasui'es 4"5 x

3'5 mm., and in a specimen of Ilyrmecophaga 3-5x3 mm. ; while the respectiA^e measure-

ments of the psalterium are about 12x2 mm. in Orycteropus and about 17 x less than

1 mm. in Ilyrmecophaga. The corpus callosum of the latter, measuring about 26 mm.

long and with an average thickness of about 2 mm., greatly exceeds in size that of

Orycteropus, which is only 21 nmi. long, and about the same tliickness as that of

Ilyrm ecoph aga.

The condition of the commissures in these two geneva points to a most decided

superiority in the brain of Ilyrmecophaga, when we recollect that the two brains are

approximately equal in size. The anterior (ventral) commissure is larger in Orycteropus

because the olfactory bulb and pyriform lobe, from which it is mainly derived, are larger

than they are in Ilyrmecophaga. But the larger corpus callosum in the Great Ant-eater

points to a marked superiority in pallial development, /. e. a distinctly higher state of

cerebral organization, in this animal than in the African Orycteropus. The psalterium

of Ilyrmecophaga is more attenuated than that of Orycteropus, partly because it has

been subjected to a greater amount of stretching * by the larger corpus callosum, but

partly because it is actually smaller in the former, a result of the smaller dimensions of

the hippocampus.

In the cerebral commissures of Tamaiidua we find a considerable family resemblance

to Ilyrmecophaga,, making due allowance for the smaller size of the former (fig. 10).

The anterior commissure, measuring about 1"5 x 1*25 mm., is placed in a vertical lamina

termiualis, which is attached dorsally to the ventral extremity of the psalterium ventrale.

The psalterium is elongated and attenuated as it is in Ilyrmecophaga, Ijeing about 9 mm.

long, and reaching a maximum thickness of 0'75 mm. ia the plumpest part of the

psalterium ventrale ; biit the psalterium dorsale cowsisXa of an extremely thin sheet of

crossing fibres. The elongated corpus callosum is more oblique than it is in Ilyrmeco-

phaga, and is nearly 14 mm. long and 1 mm. thick. The anterior and posterior

extremities of the corpus callosum are distinctly thickened.

As far as Pouchet's figure allows us to express an opmicm, Cycloturus also presents the

typical elongated corpus callosum which seems to be the distinctive character of the

family of MyrmecophagicUe among the Edentata. In brains of approximately the same

shape the proportion between the lengths of the corpus callosum and the cerebral hemi-

sphere may be taken as a rough estimate of the degree of functional perfection of the

pallium. Increase in extent of pallium and an increasing richness of texture will find

expression in an increased number of crossing fibres.

* Concerning this stretching inflnence of the corpus callosum, see '.Journal of Anatomy and Physiologj%'

vol. sxxii. 1). 41.

306

DE. G. ELLIOT SMJTIl UN

In Myrmecophaga the leugth of the corpus callosum is about 48 per cent, of the length

of the hemisjihere ; in Tamaudna it is about 41 per cent., and in Cycloturus it is about

38 per cent.

In Orycteropus, an animal of similar habits , and approximately equal size to

Myrmecophaga, the corpus callosum, which is about the same thickness as it is in

Myrmecoplwga, is only 35 per cent, of the length of the hemisphere.

The cerebral commissures in the Sloths present a marked contrast both in appearance

and in size to those of their relatives — the American Ant-eaters. We have just seen that

the characteristic feature of the corpxis callosum in the latter is its great length ; the

effect of this elongation is most noticeable in the caudal direction, and as the upper

extremity of the psalterium is attached to this extremity of the corpus callosum it follows

that the psalterkmi dorsale becomes markedly attenuated.

Fig. 17.

psalteriam

hippocamp. vestigia

bulb, olfaot. '

area praecommiss.

tubercul. olfact

Corp. oallos.

tela

fisB. prima

/ Corp. qaadrigem.

aquaeduct, Syl.

vel. medallare

'\ pone Varol.

lob.

pyriform. ooramisa. moll.

oommiss. ant. /

tract, opt'.

ventr. III.

Brain of Bradypvs tridactylua, jiiv. ; surface exposed by mesial sagittal secli

Tela refers to roof of third ventricle.

Enlarged 2 diam.

In the Bradypodid(B we find a vei'v short corpus callosum ; in three specimens of

Cholcepus tlie average length is 30 per cent, of the length of the hemisphere ; and in a

young specimen of Bradypus the j)roportion is as low as 26 per cent. These proportions

are all the more noteworthy if we recall that the hemisphere in the Sloths is itself

relatively short compared with that of the Ant-eaters.

The shortness of the corj)us callosum explains the peculiar shape of the psalterium.

For, being free from the stretching influence of a caudally elongating corpus callosum,

the psalterium remains as a small plump mass of fibres, with no division into p)saUeritmi

dorsale and ventnde. Tiiis little mass of fibres is thickest at its junction with the corjjus

callosum, and rapidly tapers to a rounded point as it extends downward and forward,

forming an angle of about 30° with the corpus callosum. It is about half the length

of the latter. Flower soys * that "the anterior end [of the corpus callosum] is simple

Flciwer. Phil. Trans. 18G.5, ]). 630.

THE BRAIN IN TH]'] EDENTATA. 307

and obtusely pointed, without a trace of tlie reflected rostrum." In my specimen of

Cholrepits, as well as in the representative of Brmhjpus, the anterior extremity of the

corpus callosum is fuller and not pointed as seems to have been the case in Plower's

specimen. There is, as Flower remarks, no reflected rostrum or genu in Cholcepus, but

in my specimen of Brad>jpuii there is a most decided genu, for the plump anterior

extremity of the short corjius callosum j^resents a considerable curve in the ventral

direction.

The shape of the psalterium and its relation to the corpus callosum in the Sloths

recall that peculiar reversion to a simpler type of cor2)us callosum which we have

previoiisly met in Nyctophilus and other Bats *. The difference is a considerable increase

in the size of the corpus callosum in the Bj-adypodidce.

Ill the Sloths the anterior commissure is relatively smaller than it is in either

Ilyrmecophaga or Orycteropus, probably because the pyriform lobe is relatively smaller

in the former.

In three schemes which I have prepared to illustrate the vai-iations in the hii^pocampus

in the three American families {vide infra, tig. 23), the shapes of the commissures are

clearly demonstrated and their marked contrast shown more forcibly than any description

can picture them.

In the Armadillos we meet with yet another type of dorsal commissure which markedly

contrasts with both of the types — those of the Bradypodidie and Myrmecophagid(e — whicli

we have just described. A representative of this type is seen in Dasypus viUosus. Here

we find a dorsal commissure composed of two limbs — corpus callosum and psalterium —

of approximately the same size, but of different shai^es. Both of these limbs are

placed very obliquely and in contact one with the other for the greater part of their

extent, only a very small part of the extreme anterior end of the corjous callosum being

separated by any interval from the psalterium. As a result, there is practically no septum

lucidum, in the sense in which that term is applied in human anatomy.

The anterior extremity of the diminutive corpus callosum is pointed and depressed.

The psalterium and corpus callosum each consist of a club-shaped mass of fibres of

approximately the same size. The thick end of the club in the case of the psalterium

consists of the cut edge of a vertical wall of crossing fibres, which are placed above the

anterior commissure. This mass is the pjsalteriiim ventrale. At its upj^er extremity it

tapers to the handle of the club, ^nliich is composed of the psalterium dorsale. This is

short and is inclined slightly backward, and becomes continuous with the thick end of

the club-shaped mass of the corpus callosum, which is placed upon the dorsal aspect of

the psalterium dorsale. The corpus callosum is extremely oblique, and rapidly tapers to

a point anteriorly aud below. A very slight interval is left between the anterior

extremity of the corpus callosuui and t\\e pjsalteriuin ventrale.

In Turner's description tiud figure of the brain of Dasypus sexcinctus t there is no

indication of any distinction between Wxe ptsalteriuni dorsale and ventrale, and the whole

* Cf. this Vol. p. 47.

t Turner. «p. cil., 'JouriKil of Anatomy and Physiology,' vol. i.

308 DK- G. ELLIOT SMITH ON

dorsal commissure is represented as an obliquely-placed, inverted, U-sliaped structure,

with symmetrical limbs of approximately the same shape and size. It seems probable,

however, that there is a very definite attenuation and bending of the upper part of the

psalterium in both species of Dusyjnis.

In Tolypeutes tricinctus. Garrod * represents a dorsal commissure of the same shape

as that represented by Turner in Dasy^ous, but with a corpus callosum slightly larger

than the psalterium. The specimen of Tolypeutes at my disposal was not sufficiently

well-preserved to permit me to supplement Garrod's brief notes.

The commissures in the brain of Xeimrus unicinctus have not hitherto been described

or figured, so far as I am aware. In the well-preserved specimen representing this

genus in the College of Surgeons, the dorsal commissure very closely resembles the

appearance figured by Turner in Dasypus f .

We can say that in the three genera Dasypus, Tolypeutes, and Xeimrus, the corpus

callosum is very small and pointed, obliquely situated, and of apj)roximately the same

size as the jssalterium.

In the specimen of Tatusia in the College of Surgeons, the psalterium presents features

similar to those which we have described in Dasypus villosm, but the corpus callosum is

considerably larger than the psalterium, and is plumpei', longer, and of more unifoi'm

thickness than the corpus callosum of the other Armadillos. In this specimen the dorsal

commissru'e as a whole w^as not unlike that found in the Hedgehog {Erinaceus) and in

the Manidfc. Such being the case, it is surprising to find the following observations of

Poucliet % : — " Sur la coupe du cerveau dc I'Encoubert [Dasyj^iis] le corps cfilleux mesure

6 millimetres de long et 1 millimetre d'epaisseur; c'est chez un jeune Cachicame

[Tatusia] qu'il nous a montre les proportions les plus exigues. Nous I'avons vu aussi,

sur cet animal, nettement recevoir des fibres de la partie anterieure et de la partie

posterieure de I'hemisphere qui viennent s'y jeter en longeant la scissure mediane."

It is probable that the immediate ancestors of the Dasypodida' possessed a considerably

larger corpus callosum than the existing types, for otherwise it would be difficult to

understand the stretching of the psalterium. If this be so, the corpus callosum has

undergone a retrogressive diminution in size, and the condition in my specimen of

Tatusia, rather than that of the other Armadillos, would be nearer the j)rimitive one.

In Chlamydopjhorits we find a very peculiar dorsal commissure conforming to the

same type as Dasyims villosus, but in which the retrogressive changes resulting in the

diminution of the corpus callosum have gone much further. We find a large psalterium

divided in a typical manner into dorsal and ventral portions, and a cor2)us callosum so

reduced in size that it is only slightly larger than the psalterium dorsale. This is one

of the most extreme forms of reduction of the corpus callosum met with in the Eutheria.

If this process of reduction were to be carried much further in Clilamydopliorus we should

reach a state of cerebral modification wdiich we find in the Marsupial Notoryctes.

* Garrod, op. cit., Proc. ZooL Soc. Loudon, 1S7S.

t Unfortunately, in tlie jirocess of mounting, a glass rod bad l.ieen jushcd through the junction of the psalterium

and corpus callosum, thus rendeiing imjitssible an acC'urate description of this region.

J Pouchet, op. cit. torn. vi. p. 309.

THE BKAIN IN THE EDENTATA.

309

There is a marked contrast between the fomily type of dorsal commissure met witli in the

Brudijpodidie and the equally Avell-defined family type of the Dasupodidtc (fig. 23, p. 320).

In the latter we find that specialized form of psalterium which we have seen in the

Ilyrmecophagidce and Orycteropus, and which is found in the vast majority of Eutlieria

—a form of psalterium which we associate with a fully-developed corpus callosum.

The diminutive size of the corpus callosum in the Armadillos therefore sviggests a retro-

gressive development from some form witli a large corpus callosum.

Eig. 18.

hippocsmp. vestigia

Corp. callos.

Corp. quadrigem

psalterium

bmbria

faBCia deotata

Jiippocamp. inversus

tract, opt

tobercul. olfact.

; lob! pytiform.

poD8 Varoi.

rorji, interped-

commiaa. moll.

Jytiform. vent, i

fisB. hippocampi

Brain of Cholapiis duhniiihis ; surface exposed by Ille.■^lal sagittal section. Enlarged .! diam.

The brain-stem has been cut away from the hemisphere.

In the Bradijpodidiv we tind a marked contrast in the shape of the commissures.

Here we have a corpus callosum Avhich lias attained a much larger size than in the

Dasypodida', though we must still regard it as relatively small and primitive. The

psalterium presents a simple form in the Sloths, which a comparison with the marsupial

would point out as a primitive type. In other words, we might regard it as the result

of a progressive development from some simpler type rather than a retrogressive modifi-

cation of a more highly organized form, as may have been the case in the Armadillos.

In all the Armadillos the ventral or anterior commissure is relatively very large, just

as we should expect from the large size of the pyriform lobe.

In the brain of Manis the corpus callosum is very short, being barely 6 mm. long in

the specimen at my disposal, and almost of imiform thickness throughout. It does not

taper anteriorly, nor, on the contrary, is it thickened or bent anteriorly to form a genu.

In my specimen the corpus callosum was not nearly so thick and plump i]i proportion to

its length as that figured by Ma.^ Weber *.

Max Weber has not figured the whole of the psalterium, but this structure in my

specimen appears to be clearly composed of two parts — a ventral and a dorsal, neither of

which is very plump. So that, on the whole, the dorsal commissure of Jlanis is mitcli

more like that of Eriiiaceus than any of the Edentates ; for, while the psalterium resembles

that found in the Dasypodldce, the corpus callosum is more like that of the BradypodidcB

in shape, size, and position.

The anterior commissure is moderately large.

* Max Weber, op. cit., ' Zool. Ergebnisse,' ii. tab. i.v. fig. (j9 co.

SECOND SERIES. — ZOOI.OGY, VOL. VII.

43

310 DE- G. ELLIOT SMITH ON

In reviewing the features presented by the cerebral commissures in the Edentata, we

find that, while each family presents a more or less distinct type of dorsal commissure,

all of the commissvires conform to the type prevailing in the Eutberia generally, and an

analogue for almost any Edentate type may be found among the Eutberia.

There is no feature in the arrangement of the commissures which indicates a transition

stage between the primitive Saiiropsidan -like type which prevails in the Prototheria and

the Eutberian brain with a well-formed coi'pus callosum. It may be that the gradual

dwindling of the corpus callosum which is obviously going on in the Armadillos may

indicate the mode by which the Marsupials might have lost their corpus callosum, when

their dorsal commissure assumed a resemblance to that of the Monotremes in being purely

hippocampal. Eor the possibility of the Marsupials having once had a corpus callosum

and subsequently lost it is forced upon our consideration by the dwindling of the

anterior and dorsal parts of the hippocampal arc — changes which we associate causally

in the Eutberia with the development of a corpus callosum. But the discussion of the

question whether the ancestors of the Marsupialia originally had a corpus callosum

must be postponed for a future memoir.

There are certain general questions relating to the cerebral commissiu-es which may be

discussed to better })urpose after we have considered the cerebral cortex.

The Hippocampal Formation.

We have seen elsewhere * that in the Monotremata and Marsupialia the hippocampus

retains a peculiarly simple arrangement with relation to the margin of the hemisphere,

which it has inherited from the ancestors of the Mammalia.

In approaching the study of this region of the brain in the Edentata, I have deemed

it important to enter with some detail into the exact arrangement of the hippocampus, in

the hope that some indication of the affinities of the Order might be obtained.

Extending downward and backward from the postero-iuferior aspect of the psalterium,

we find upon the mesial surface of the hemisphere (fig. 4, p. 291) two or more peculiar

arcuate bands, which represent all that can be seen upon the surface of the pecviliar hipjjo-

campal formation — the homologue of the hippocampus major of human anatomy. If,

before beginning the study of these ])eculiar surface areas of the hippocampal formation,

we examine this structure from within by opening up the cavity (lateral ventricle) of

the hemisphere, we shall gain a much clearer conception of the region than would be

the case otherwise.

If we dissect away the lateral wall of the hemisphere of Ori/cterojjus so as to expose

the mesial wall of the lateral ventricle, we find a large crescentic white mass bulging in

the posterior part of the ventricle, looking not unlike the pupa of a silkworm lying in its

cocoon. This large curved swelling is the hippocampus. Its concave anterior border

is fringed by a prominent ridge of compactly arranged fibres — the fimbria. The lower

extremity of the swollen mass is pointed, and the upper extremity, which extends slightly

* Cf. this Vol. p. 47.

THE BRAIN IN THE EDENTATA.

311

further forward than the lower, is rounded and is placed upon the dorsal side of the broad

anterior end of the fimbria.

ventr. olfact,

fiss. rhinal.

: ped. olfact.

bulb, olfact.

lob. pyriform.

.' ; tract, opt. ; liiPPOcamP-

Corp. paracommisB. • fimbria

commiss. ant.

Left hemisphere of Orycteropus ; the lateral wall removed and the lateral ventricle opened. Nat. size.

x. " Complete " invagination of the ventral wall of the olfactory bulb.

If we make a horizontal section through this hippocampal swelling at about the middle

of its extent, we gain a more exact idea of the extent of the prominence and the

relationship between those parts of the hippocampal formation which make their

fascia dentata

inversus . fascia ;

dentata:

fimbria

fiss. hippocampi

pallium

Semi-schematic representation of a transverse section through the hippocampal formation in Ori/ctcropus.

Enlarged 4 diam.

X. Hippocampo-pallial junction, i/. Corona radiata.

appearance upon the surface and the deeper-lying parts which produce the large

ventricular bulging.

In such a section the hippocampal formation presents, roughly speaking, an elliptical

43*

312 DR. G. ELLIOT SMITH ON

outline, and the greater part of its free surface is covered by a very definite layer of

medullated nerve-fibres — the alveus.

The anterior border of the formation is rounded, and from the antero-mesial part of

the cui've a small triangular mass of fibres — -the fimbria — projects. This spur serves to

indicate the line of demarcation between the ventricular and extrave utricular surfaces

of the hippocampus. The whole of the ventricular and the greater part of the extra-

ventricular surfaces (in this section) are covered with a A'ery well-defined layer of

medullated nerve-fibres — the alveus. Extending in the lateral direction from the fimbria,

the alveus extends outward and then sweeps in a large curve caudally and extends back-

ward as far as the posterior aspect of the ventricle, of which it forms the mesial wall.

From the extent and degree of curvature of this large alveus-coated sui"face in the figure,

we can appreciate more readily the great size of the Ijulging of the hippocampus into the

ventricle (fig. 19). The alveus gathers fibres from the whole of the deep or ventricular

surface of the hippocampus and conveys them by an oblique course to the iimbria, which

is composed of a large mass of such fibres gathered into a compact bundle. But the

alveus is not confined to the ventricular aspect of the hippocampus. Eor we find an

extraventricular alveus extending backward from the fimbria upon the mesial surface of

the hemisphere for a considerable distance until it meets a grey band of peculiar

constitution — the fascia dentata.

The fascia dentata is morphologically the extremely specialized margin of the costa,

which has undergone a peculiarly modified hypertrophy in its superficial layers, resulting

in that curiously folded layer which is known in human anatomy as the fascia dentata.

[It is not advisable to apply the term gyrus to this structure, as many writers, following-

Huxley, are in the habit of doing, because it is not a gyrus in the ordinary sense of the

term, but merely the peculiarly modified sujjerficial region of a cortical area.]

An exceedingly small fragment of the fascia dentata makes its appearance upon the

surface in the section we are considering, since almost the whole of its real surface is

hidden from view l)y being opposed to the morphological sui'face of the hippocampus and

the adjoining cortical area.

In the section we find the superficial fragment of the fascia dentata at the posterior

extremity of the extraventricular alveus ; from this point the fascia dentata extends for

a considerable distance in the lateral direction and in apposition with the area of cortex

which adjoins the hippocampus proper. The fascia dentata then bends forward, its surface

now coming into contact Avith the morphological surface of the hippocampus ; in the rest

of its course the fascia dentata pursues a course parallel to the alveus : that is to say, it

pi'oceeds forward and then curves mesially and then slightly backward. The potential

cleft which extends into the cortex in the interval between the fascia dentata and the

geoeral cortex and separates t];e morphological surface of the fascia dentata from the

surfaces of the hippocampus and the adjoining cortex is the fissura hippocampi. The

deeper parts of this "fissure" are merely potential, because the surface of the fascia

dentata becomes adherent to the opposed surfaces, especially that of the hippocamjjus.

The hippocampal fissiu'e is unique in its nature and mode of formation, and cannot be

classed with any other fissures of the brain.

THE BRAIN IN THE EDENTATA. 313

Behind the liippoeampal fissure, in the section we are considering, we find the general

cortex forming' the posterior lip ol" the fissure. If we trace this cortex toward the

hippocampus, we find that its superficial layer becomes directly continuous with that of

the hippocampus. The change from general cortex to hippocampus takes place opposite

the bend in the hippocampal fissure, and consists essentially in the levelling down of

the scattered cell-elements of the general cortex into a regular column of cells of peculiar

shape, which characterizes the hippocampal formation. We may call this region the

hippocampo-pallial junction. From this point the hippocampus proper extends forward,

its deeji surface coated with alveus forming the mesitil wall of the ventricle, its real

surface being in apposition Avith that of the fascia dentata. The hippocampus, still

maintaining these relations, extends forward, then curves around so that its "deep"

alveus-coated surface sweeps beyond the fimbria and thus makes its appearance upon the

surface of the hemisphere. In this manner the morphologically deep as^iect of the

hippocampus actually forms part of the surface area of the hemisphere ; in other words,

part of the hippocampus becomes completely invested, with its " superficial " area

excluded from the actual surface and its " deep " aspect exposed. This area of the

surface of the brain, which is placed between the fascia dentata and tlie fimbria, and

is covered by extraventricular alveus, may be termed the " hipjiocampus inversus." The

whole of the " morj)hological surface" of the hippocampus proper is hidden from view in

tliis section because it is submerged in the depths of the hippocampal tissui-e.

After these considerations we may better appreciate the appearance of the mesial

surface of the hemisphere.

In a mesial view of the hemisphere of Orycteropus (fig. 4) we see the fimbria beginning

below at a point just beliind the optic chiasma as a very narrow band and extending obliquely

upward and backward, then curA'ing upward and ultimately horizontally forward to the

situation of the psaltcrium ventrale. It rapidly increases in breadth during its course from

below upward. If, instead of examining this region from its lateral aspect, we look at it

from below (fig. 21), we find tliat for its upper half the fimbria follows a very oblique

course forward and inward, so that anteriorly it approaches close to the mesial plane,

and a large proportion of its fibres extend across to the other side of the Ijvain, thus

forming the 'psalterlam ventrale. The fimbria presents analogous features in all the other

Edentates, in common with most lowly mammals. Lying behind the fimbria, we find in

Orycteropus the area of inverted hippocampus which separates the fascia dentata from the

fimbria. As we trace these structures upward, we find that the area of inverted hipjDO-

campus rapidly tapers, and at the same time the fascia dentata In-oadens and approaches

the fimbria. The exact arrangement of the upper endings of these three bands will be

discussed after the inferior' endings are considered. In Orycteropus the inverted hij)po-

campus and the fascia dentata appear to end suddenly below in a deep arcuate furrow

(fig. 1) which marks the upper limit of the peculiar hippocampal tubercle, to which a

bj-ief reference has already been made. As this hippocampal tubercle exists among the

Edentata in Orycteropnis only, we may witli advantage consider the mode of termination

of the hippocampus in the other forms first. In all Edentates we find the three super-

ficial bands— ;;^"/«Z//7Vr, hippocanqjits inversus, and fascia dentata — which we have noted

314

DE. G. ELLIOT SMITH ON

in Oiycteropns. As we trace these bands downward and forward in any Edentate other

than Orycteropiis, they will be found to taper and end simply just behi]id the optic

chiasma. This mode of ending is shown in the figure of Tamanchia (fig. 10), and Max

Weber's figure shows it in Mauls. In his account of the state of the hippocampus in

Fis. 21.

hippocamp. nudus

fascia dentata

fascia dentata f-

hippocamp. inversus

Corp. striat

fimbria / . ' ^

psalterium l'"'^' P^aoonimiss.

colum. fornicis

fiss. hippocampi

Dissection to expose the ventral surfaces of hinder parts of the cerebral hemispheres in Orifcterojnis.

Enlarged ^ diam.

.V. Purrow corresponding to hippoeampo-pallial junction.

Cholopjms, Flower * mistakes the inverted area of hippocampus for part of the fascia

dentata. In many of these brains the inferior extremity of the fascia dentata may be

seen, upon the ventral sixrface of the brain, in direct continuity with that part of the

pyriform lobe Avhich Gustav lletzius calls the " gt/rus lunaris." This is shown in our

figure of 3fi/)-mecophaga (fig. 6), in which the antero-inferior extremity of the fascia

dentata makes a peculiar bend toward the fimbria and almost at right angles to the rest

of its course.

In Orycteropus, however, we find, the region of the ventral extremity of the hippo-

campal formation occupied by the peculiar large oval swelling which I have called

tubei'culwn hiiiiJOcumxn. We may at a glance appreciate the significance of this peculiar

structure if we remove the lower extremity of the hippocampal formation from the rest

of the brain and examine it from the front, so that we may at the same time see part of

the ventricular surface of the hip^iocarajms and the whole of the extra ventricular jiarts

(fig. 22). We then see the fimbria descending and rapidly vanishing as a distinct ridge

by the scattering of its fibres over the lower parts of the hippocampus. In front of the

fimbria we can see the lower part of the ventricular surface of the hippocampus, which

we haA^e already seen in profile (fig. 19). We see this alveus-coated surface of the

hippocampus sweeping around the lower extremity of the fimbria and becoming extra-

ventricular as the tuherculum Idppocampi. The latter structure is obviously nothing else

* Flower, op. cit., Phil. Trans. 1865.

THE BEAIN IN THE EDENTATA. 315

thau a promiuoiit boss of inverted hippocampus covered with, an exceedingly attenuated

coat of extraventricukr alveus, and therefore serially homologous with the flattened

.-v..^°-"''

KO"^'''

4*8

fimbria f ; ,• " ^.f^^^^j^ Jentata

alveus

W^ '■ fiss. hippocampi

tubercul. ,.■%. J/r^^^

hippocampi xii^:^^^ 'ob. pyriform.

"x

Dissection to expose ventral extremity of the hippocampal formation in Ori/cterojnts. Nat. size.

.!-. Attenuatcfl lower extremit_v of fascia dentata.

band of inverted hippocampus which separates the fascia dentata from the fimbria. But

the lower extremity of the fascia dentata has not entirely disappeared, for it is repre-

sented by an extremely attenuated band which separates the hipjiocampal tubercle from

the pyriform lobe just as the "band of Giacomiui " does in the human brain. The

tuhercidum hippocampi is exactly analogous to the tip of the uncus in human anatomy,

which E,etzius has recently called the gyrus iiitralimhicus* .

Such an arrangement, so far as I am aware, exists nowhere else outside the Primates.

As the hippocampal formation proceeds upward toward the psalteriiim and splenium

of the corpus callosum it at the same time rapidly approaches the mesial plane, so that

a perspective view, such as a representation of the mesial surface of the hemisphere

affords, gives a very distorted picture of the hippocampal region. To gain an accurate

idea of this region we must examine from below those large opercula-like cortical folds

which form a dome-like roof al)ove the optic thalamus and corj)ora quadrigemina. Such

a view may be obtained by making a horizontal section immediately above tlie anterior

commissure and inverting the upper part of the cerebral hemispheres (fig. 21). In this

view we may start from the typical section of the hippocampus which has been described

above (fig. 20), and Avhich is now exposed once again. We see tlie fimbria extending

obliquely forward and inward toward the columna fornicis, the elliptical section of which

is seen on each side of the mesial plane. Many fibres of the fimbria enter the columna

fornicis of tlte corresponding side ; many other fibres of the fimbria cross the mesial

plane just behind the coliimncc fornicis and thus form the psalterium veiitrale.

The area of inverted hippocampus which in the cut surface is placed immediately

behind the fimbria may be observed to rapidly taper and soon disappear as the mesial

plane is approached.

But as the fascia dentata approaches the mesial plane it increases considerably in

* Gustav lietzius, op. cU., ' Das Mensclieuhiru.'

316 DR. G. ELLIOT SMITH OiN"

breadth : in other words, an increasing area of that part of the fascia dentata which is in

contact Avith tlie cortex {ride figure 20) becomes exposed. Pari passu with this un-

covering of the fascia dentata, the opposed surfaces of pallium and hippocampus, which hide

it from view elsewhere, also hecome exposed. There is a general unrolling, as it were,

of the hippocanipal formation. So that, as the fascia dentata becomes more and more

exposed, we also find that the hippocampo-pallial junction approaches and ultimately

appears upon the surface as a shallow furrow separ-ating the pallium, which lies behind

it, from the exjjosed surface of the hippocampus, which now makes its appearance on the

surface in front of the furrow (fig. 21, x).

This exjwsed lup]iocampus {/dppocampus nuchis) is the true morphological surface of

the hippocampus which elsewhere is submerged, hidden in the depths of the hipjiocampal

fissure *. Near the mesial j)lane it appears to emerge from the hippocampal fissure, and

under the name " Ballenioiiidung ," which Zuckerkandl introduced, it has given rise to

much discussion. Zuckerkandl's " Ealkeuwiudung " is nothing else than our '■'■ hippo-

campus nndusr

As the fascia dentata becomes more ex2:)0sed and apparently broader it bends trans-

versely inward, and when quite close to the mesial plane it bends suddenly backward and

rapidly tapers to a point l)elow the splenium of tlie corpus callosum. These recurved

portions of the fascise dentatte upon the two sides of the mesial plane are in close

proximity the one to the other, and in many animals [c. (j. the Rabbit) they actually

meet and fuse in the course of development f . But the two structures arc development-

ally independent, and each is derived w holly from its own cerebral hemis2)here.

If we now return to the consideration of the mesial surface of the hemisphere (fig. 4),

we readily recognize the mesial border of this infrasplenial bent part of the fascia dentata

as a pear-shaped body proceeding backward upon the imder surface of the psalterium

dorsale and splenium, and appearing to be directly continued around the splenium on to the

dorsal surface of the corpus callosum as a rovmded white cord. But the fascia dentata

really ceases, as a definitely recognizable entity, upon the ventral surface of the splenium.

The rounded white cord which surrovmds the splenium, and a2)pcars to be merely the

attenuated fascia dentata, is more directly the upwai-d continuation of the hippocampus

iiudus, i. e. the hippocampus proper.

The fascia dentata, as its mode of develojiment indicates, is a comparatively late

specialization of the margin of the hipjiocampus projier. As it develops it rolls itself,

as it were, over the surface of the hippocampus and hides this from view. On the

inferior aspect of the splenium the hippocampal formation unrolls, the hippocampus

proper becomes once more exposed, the fascia dentata tapers and disappears almost

entirely, and a remnant of the more primitive liif)pocampus proper surrounds the

splenium and extends along the whole length of the upper surface of the corj)us callosum

as a rounded w^hite cord.

This cord-like remnant is a vestige of the anterior part of the more extensive hippo-

* The true significance of this will be appreciated at a glance from fig. 21 of my short memoir in the ' Journal of

Anatomy and Physiology,' vol. xxsii. p. 49.

t Compare in this connection the comparative observations of Stieda in Zeitsch. f. wisscnsch. Zoologie, 1870.

THE BRAIN IN THE EDENTATA. 317

campal arc which we find in Marsupials and Monotremes *. la Orycternpus this circum-

callosal hippocampal vestige is a very ])rorainent rounded strand whicli we can readily

follow with the naked eye around the spleuiura, along tlie whole length of the corpus

callosum, and around its anterior extremity. But beyond this we cannot thus follow it.

We shall see that in most of the other Edentates the mode of termination of this

vestige of the anterior part of the hippocampal arc is more clearly exhibited than it is in

Orycteropiis.

Turning to the consideration of the brain of Tamandua (fig. 10), we find a typical

hippocampal formation, three concentric bands of which — fimbria, inverted hippocamj)us,

and fascia dentata — appear upon the surface. These three bands end simply below, i. e.

without that peculiar modification which in Onjcteropus was described under the name

hippocampal tubercle. At its upper extremity we find the same series of circumsplenial

modifications of the hippocampal formation as we have already described above. But

the infrasj^lenial bending of the fascia dentata is much further removed from the

psa/terium ventrale than is the case in Orycteropus : in other words, the corpus callosum

has grown relatively further backward, carrying the infrasplenial hipjiocamjial flexure

{flexura hipp)ocampi) with it, and has extended the pi^^^ltermm dorsale to permit this

separation from the psaUerimn ventrale.

A large supracallosal vestige of the hippocampus may be recognized upon the dorsal

aspect of the corpus callosum in Tamandua, but it is relatively smaller than the corre-

sponding vestige in Orycteropus. The deep cleft which separates the hippocampal

vestige from the overhanging pallium corresponds to the callosal fissure of human

anatomy. It is not, as is often erroneously stated, the continuation of the hippocampal

fissure, because the latter always ceases in the Edentates, as in most Eutheria, imme-

diately below the splenium of the corpus callosum when the hippocampus unrolls. The

hippocampo-pallial limiting furrow, Avhich emerges from the upper extremity of the

hippocampal fissure, surrounds the splenium, and joins the fissura cnllosalls, is often

mistaken for the hippocampal fissure itself, and hence the belief in the continuity of

hippocampal and callosal fissures. Unlike the condition of affairs in Orycteropus, the

Jissura callosalis in Tamandua becomes continuous anteriorly with a well-defined fissure

which arches downward and forward to disappear in the deep cleft which separates the

upper surface of the olfactory peduncle from the apex of the hemisphere. This is the

ventral boundary of the pallium, and hence may be called fissura limitans p)allii. It

serves to indicate to the naked eye the upper limit of the hippocampal vestige which we

can discover along this line by histological examination.

In Myrmecophaga wo find a close agreement with the condition just described in

Tamandua. There is also a large and clearly-defined hippocampal vestige, which Forbes

has failed to indicate in his figure of tlie mesial surface. However, he speaks of the

fascia dentata " being continued, as described by Professor Turner in Dasypus, as a thin

layer of longitudinally-disposed fibres over the corpus callosum to near its genu" f.

* Cf. this vol. p. 50 ; also ' Journal of Anatomy and Physiology,' vol. xssii.

t W. A. Forbes, op. cit., Proc. Zool. Soc. London, 18S-', fig. 4, and p. L'iJ4.

SECOND SERIES. — ZOOLOGY, VOL. VII. 4,^

318 DR- G. ELLIOT SMITH ON

As a description of tlie mere appearance of the hippocampal vestige in Myrmecophaga

this account is lucid enough, but if we literally iuterpret either it or the expression of

Turner (Avhich it somewhat ti'avesties) as a statemeat of the actual constitution of the

parts we shall gain a very erroneous conception. For, as tlie hij^pocamjjal formntion

surrounds the splenium, the fascia dentata dwindles and practically disappears, leaving

the diminutive remnant of the simple hippocampus proper upon the surface of the corpus

callosum. This hippocampal vestige is very rich in longitudinal inedullated fibres, which

in human anatomy are called the strice Lmicisii (as well as an immense variety of other

names). This explains the statement of Turner that the fascia dentata is prolonged into

tlie upper surface of the corpus callosum as a narrow band *, which, to the naked eye, it

appears to be. It also explains the statement, which Eorbes wrongly attributes to

Turner, that the fascia dentata is " continued forward as a thin layer of longitudinally-

disposed fibres."

Histological examination enables us to exactly interpret the puzzling macroscopic

appearances and to state definitely that the hijipocampal formation, a complex of fascia

dentata and hippocamj)us (in the narrow sense), extends up to the splenium of the

corpus callosum and becomes continuous around tlie S[)lenium with a diminutive baud

which represents the dwindled hippocampus from which the fascia dentata has

practically vanished ; as this vestigial liippocampus contains a large number of

me;lullated nerve-fibres, it is often mistaken for a purely fibrous structure.

Although tbe figure of the mesial surface of the brain of Cycloturus which Pouchet

gives + is lacking in detail, it suffices to show that a sulcus limitans pallii exists in a

form exactly analogous to that of the other two representatives of the Myrmecopjhagldcc ;

and the fact that his figure represents a vestigial hippocampus at all shows that this

structure is more prominent than is usual among Eutlieria.

Flower has given a useful figure and a descrij)tion of the hippocampal region in

Choloepus X, but the corresponding region in Bradypus has not, so far as I am aware,

been properly figured or described.

In the brain of both of the Sloths the hippocampus presents the typical features in

the greater part of its extent, such as we have already described in Tamandua, and

which we find in most mammals. But in the upper part of its extent the hippocampus

presents in both Bradypodidce certain features in common which distinguish it from

that of the other Edentates. We have already observed that in this family the corpus

callosum has not grown backward even to the same extent as it has in Orycteropus. As

a result the psalterium, as we have already seen, is short and sim[)le, and in addition the

upper part of the hippocampal formation has undergone very slight disturbance. In

both Sloths the fascia dentata appears to extend directly toward the splenium without

such a marked infrasplenial flexure as we find in the other Edentates. To the naked

eye no area of exposed hippocampus makes its appearance behind the splenium, and the

* W. Turner, op. cit., ' Journal of Anatomy and Physiology,' vol. i.

t G. Poucliot, op. cit., ' Journal do I'Anatomie et do la Physiologic,' tome vi. pi. iv. fig. 4.

J W. H. Flower, oj). cit, Phil. Trans. 18G5.

THE BEAIN IN THE EDENTATA. 319

hippocampal fissure even appears to extend into contiuuity with the callosal fissnn;.

Looking at the mesial surface of the hemisphere, the upper part of the fascia dentata

appears to accompany the fimbria right up to the splenium and then to pass without any

marked bending into the vestigial hippocampus which covers the dorsal surface of the

corpus callosum.

A large supracaliosal hippocampal vestige is found in both Sloths, and in my specimen

of Bradijpus we have an interesting demonstration of the precallosal course of the hippo-

campal vestige. Thus we find extending obliquely downward and forward from the

front of the corpus callosum two shallow furrows which slightly diverge as they approach

the olfactory peduncle (fig. 17). The upper of these furrows corresponds to the limiting

fissure of the pallium in the 3Iijr7necophagid(B . The area included between these two

furrows is the precallosal part of the hippocampal vestige. It appears broader than the

supracallosal part of the vestigial arc because the latter is flattened horizontally upon the

corpus callosum, while the precommissural vestige is vertical, being a constituent part of

the mesial wall of the hemispheres.

In representing the hippocampus from any one point of view it is impossible to convey

an accurate idea of its exact disposition, because it bends about in various planes during

its course so that in a perspective drawing it appears distorted. As it is a matter of great

importance to clearly understand the behaviour of this importaut and peculiar part of the

brain, I have drawn three schemes (fig. 23) : one of Tamandua, representing the Ant-

eaters; one o? Choloepns, representing the Sloths, which Ave have already discussed; and

one of Dasi/p'us villosus, representing the Armadillos, which we shall consider almost

immediately. These schemes represent the actual relations of the hippocampal formation

to the commissures in the three American families of Edentates.

After the preceding descriptions these schemes are almost self-explanatory. In the

Ant-eater (A) we see the three bands of fimbria (Ji-), inverted hippocampus (i.h.), and

fascia dentata (f.d.) ascending in front of the hippocampal fissure (h.f.), just as they do

in the Rabbit or any of the common Eutheria. As they ascend, the intermediate band

(inverted hippocampus) disappears and the fascia dentata comes into contact with the

fimbria. Tlie main portion of the latter continues its forward course to the p)salte)'lmn_

ventrale (;ps.v.), but a few of its uppermost fibres become widely scattered in tlie

triangular interval bet^veen the subsplenial flexure of the fascia dentata (f.d.'} and the

fibres going to the ventral part of the psalterium. Erom these scattered fibres the thin

Taemhranous psalterium doi^sale (ps.d.) is formed. The fascia dentata (/.''/.) suddenly

diverges from the fimbria and bends backward beneath the splenium (spl.) of the corpus

callosum. As it does so it rapidly tapers and fades away. As this is taking place a part

of the true hippocampus (u.h.) (using that term in the strict and exclusive sense) crops

out of the upper part of the hippocampal fissure (hf). This little fragment of naked

hippocampus {n.h.) becomes directly continuous with its atrophied serial homologue, the

vestigial hippocampus {v.Ji.), which surrounds the corpus callosum (c.c.) and extends

forward not only as far as the genu {(/.), but beyond this point toward the situation of

the olfactory peduncle.

U*

320

DR. G ELLIOT SMITH ON

TiK. 2-3.

Three schemes to represent the relation of the hippocampal formation to the commissures in the

Mynnecoj^Jtcyidce (A), the Bradijpodidw (B), and the Basi/podida' (C).

Reference Ictte

e.c-

.</•-

spl-

ps.v.-

2^s.d.-

a.c-

l.t.-

It'.

p.-

-Corpus eallosum.

- Genu corporis callosi.

-Splenimn corpioris calloni.

-Psaltcrium venirale.

-Fscdterium dorsale.

-Commissura anterior.

-Lamina terminalis.

-Lamina terminalis (the intercommissural

copidii).

-Area jiro'commissuralis.

-Area pracoinmissuralis (pars dorsalis =septum

lucidum).

f.d. — Fascia dentata.

f.d'. — T\ie fascia dentata at ih.c Jle.vxu'a hippocampi.

Ji. — Fimbria.

i.h. — The inverted hippocampus.

h.f.- — Fissura hippocampi,

n.h. — Uippocauipms nailiis^the exposed surface of

the hippocampus proper.

v.h. — The vestiges of the hippocampus (supracallosal

P'lrt).

v.h'. — Tlie vestiges of the hipjwcanipus (precallosal

part).

In the Bradyiiodidce we have a peculiarly simjile arrangement of hij)poeampal

formation, which is all the more remarkable because it forms such a marked contrast to

the typically Eutherian type we have just found in the Ant-eaters. The small corpus

eallosum has produced a minimum disturbance in the circurasplenial parts of the

hippocampal arc. Tliere is practically uo flexura hippocampi, no appearance of the

naked hippocampus. On the other hand, the fascia dentata extends directly toward the

splenium and gradually tapers aud fades away without bending. The other changes i]i

this scheme are self-explanatory.

We will now turn to the consideration of the hippocampal formation in the Armadillos,

the type of which is rejiresented in the third scheme (C).

In all the Dasypodidce examined we find the tyjjical arrangement of the hij^pocampal

formation such as is common in the Eutheria. The A'estigial hippocampus {v.hS) is

relatively very large.

In Xeniirus we have a beautifully clear demonstration of the arrangement of the

parts under consideration. The vestigial hippocampus is a plumj) arcuate cord, which

surrounds the diminutive corpus eallosum, and then bends downward and forward in

front of the commissure.

It is equally prominent in Dasypiis sexcinctus aud Dasypus villosus (fig. 23, C) and in

THE BRAIN IN THE EDENTATA. 321

Tolypeutes ; and in the small brain of ChlamydopJwrits (fig. 16) we again find an

admirable demonstration of the arrangement of this archaic hippocampal arc. In the

small brain of Chlaniudophorus I have traced in a complete series of sections the series of

changes in the hippocampus as it surrounds the spleniiim of the corpus callosum and

joins the su2:)racallosal vestige, and found that they agree in all points with the transition

region in such simple Eutherian brains as those of Erinaceus. These changes need no

description if we compare the schemes C and A in fig. 23.

hippocamp. vestigia

fimbria

^'\faspia dentata

bulb, olfact.i- V-y yr^%^'tip5fean.pi

hippocamp. inverBua

area praecommisa. :

taberoal. olfact.

Mesial surface of right cerebral hemisphere of Xeniu-us uniciiictus. Nat. size.

In Man is we find an exactly analogous arrangement. The large vestigial hijjpocampus

Avhich I found in my specimen is not shown in Mas Weber's figure {loo. cit.), but

probably goes to swell the thickness of the corpus callosum.

In the preceding pages I have entered into considerable detail concerning the exact

disposition of the hippocampal formation in Orijcteropus and the Ant-eaters for several

reasons.

In the first place, if the Ant-eaters occupy the lowly position near the bottom of the

mammalian phylum which is usually assigned tliem, we might expect some indication

of this fact in that region of the brain which has undergone such a striking modification

Avithin the Eutheria, namely in the hippocampal formation. Instead of this, Ave find the

typical Eutherian plan in as fully developed form as that of the Ungulata and

Carnivora.

In the Sloths, it is true, we find an arrangement of hippocampus which is as simple as

it is pos>il)le to be in the presence of a corpus callosum. But the resemblance of the

condition in the Sloths to that which we have found in certain small bats *, and which

is obviously a reversion-type, suggests that the simplicity of the Sloth brain may possiljly

not l)e primitive. At the same time Ave must recognize the possibility of the archaic

simplicity of type being retained, just as it is, for instance, in the case of the auditory

ossicles according to Kitchen Parker. In the Armadillos, again, we have the typical

Eutherian plan exemplified.

The relatively large vestigial hippocampus in these Edentata invited a minute study

in the hope of finding some definite indications of its original structure; but here again

* Cf. this vol. p. 58.

322 DK. G. ELLIOT SMITH ON

we find tliat the structure is quite as atrophic as the relatively much more insignificant

vestiges of the hippocanipus in the more highly-organized mammals.

There is another reason of quite different natui'e for entering so minutely into the

anatomy of this region in the Edentata. The clear demonstration of the hippocampal

region which the Edentate brain affoi'ds rendei's it a particularly suitable object upon

which to demonstrate the typical features of a region which has given rise to groattr

perplexity, perhaps, than any other of the brain.

Eor u.any years the question of the mode of ending of the dorsal extremity of the

liippocampus has excited a great deal of controversy. Several investigators have from

time to time given an acciu-ate account of its behaviour in different mammals. Thus

Henle and Giacomini long ago demonstrated that the hippocampal formation extends

on to the dorsal aspect of the spliMiium in Man. Other writers, on the other hand, have

emphatically denied this and affirmed that the hippocampus is always subcallosal.

Other writers, again (such as Zuckerkandl, who has a large following), have stated that

the fascia dentata extends on to the upper surface of the corpus callosum. Then, again,

Ganser says that in the Mole the fascia dentata ceases upon the ventral aspect of the

corpus callosum, but that the layer of pyramidal cells {i. e. the hippocampus proper)

becomes continuous with the rudimentary supracallosal ijidusium. We have, then,

in the literature of this subject four mutually contradictory beliefs concerning the

mode of termination of the upper extremity of the hippocampus, each maintained by its

own supporters with much cogency.

We have already seen in the different Edentates that the manner in which the hippo-

campus terminates can be clearly demonstrated, and we can also see with the naked eye

the cephalic extension of the hippocampal vestige, not only to the anterior extremity cf

the corpus callosum, but also as far as the olfactory peduncle. No other writer upon

this subject seems to have even suspected the presence of this cephalic extension of the

hippocampus. Eor it has been possible, upon the evidence of comparative data, to

definitely state that the indus'mm is not only continuous with the hippocainpus, but in

itself atrophied hippocampus *.

" The Pabacommissueal Body."

In examining the mesial surface of the hemisphere we find, in front of the psalterium

and ventral commissure, a region to which passing reference has been already made as

the area piYrcommissitralis. This term was originally introduced by the writer as a

pui-ely descriptive title for a region of doubtful identity in front of the cerebral

commissures in Ornithorhynclms. This was subsequently shown to he the surface of a

large ganglionic mass to which the name corpus prcecommissurale was given t. In the

course of further investigations which were carried on after the introduction of the

* For the evidence of this point see ' Journal of Anatomy and Phj'aiology,' irp, cit. vol. xxxii.

t Cf. " The Origin of the Corpus Callosum," this volume, p. 47.

THE BRAIN IN THE EDENTATA. 323

former term, I was able to clearly establish the identity of the area pra;commissuralin

with those surface-areas corresponding to sejji/im lucidum and gyms snbcallosns (Zucker-

kandl) of the human brain. Taking into consideration the fact that these two areas are

merely parts of one and the same formation, the separation of which into two parts is

purely arbitrary in most mammals, it seemed desirable to retain the term " area pra--

commissuralis " for the whole surface-region, even though the term may not be so apt

elsewhere as it is in the case of Ornithorlnjuchus and the Submammalia.

The term " precommissural area " sufficiently explains the locality of the region to

which it is meant to be applied in all vertebrate brains. The term " ])recommissu7-at

body''' however, is not nearly so appropriate a title for the ganglionic mass whose

surface is the pi'ecommissural area, and in many cases it is singularly inappropriate.

By substituting for it the name '' paracommissioral body " we shall obtain a term which

may justly be applied to tliis important ganglionic mass in any vertebrate. Unlike

the term "precommissural area," which was introduced much earlier, the term "pre-

commissural body " has not yet been adopted by other writers, and hence there can be

no objection to the substitution of the more apt title " corpus paracommissurale " for the

ganglionic mass which I had previously called the " corpms prcecommissurale."

The need for some definite name for this mass of grey matter which forms so prominent

a constituent of the brain in the E,eptilia, Amphibia, and Dipnoi has been felt for a

considerable time. The terms " septum lucidum" and "gyrus suhcallosus " are not onlv

meaningless but inaccurate when applied to any other brains than the most bighly

organized of the Mammalia, and their application to such brains as the Prototherian.

Saurian, or Amphibian cannot fail to give rise to great misconception. Nor can these

terms be applied with any more propriety to the Basypodidce.

In the dissection of the lateral ventricle of Orycteropus (fig. 19) the paracommissural

body makes its appearance in tlie interval bet^reen the anterior commissure and the

corpus callosum as a very plump mass of grey matter w^hich forms a most marked contrast

to the surrounding areas because they are all lined wdth white meduUated tibres. The

posterior margin of this body is abrupt and rounded, and appears as though it were placed

on the lateral aspect of tiie fimbria. Anteriorly the paracommissural body graduallv

sliades away toward the tunnel in the olfactory peduncle.

The paracommissural body is separated from the corpus striatum by the slit-like lateral

ventricle. It is unnecessary to enter into a description of tbe corpus striatum or lateral

ventricle in this place. These features of the brain do not appreciably dilfer from those

of common Rodents such as Lepus.

The essential features of the paracommissural body are similar in all the Edentates.

The shape of the body, however, is modified considerably by the growth of a corpus

callosum, and hence it is very variable in the ditferent families. These changes in shape

are best appreciated from a study of the mesial surface of the hemispliere, Avhere the

paracommissural body enters into the constitution of the w^all of the brain formin"- the

precommissural area.

In the Sloths (figs. 17, 18, and 23 B) we see the typical arrange.-ncnt of the precom-

324 DE. G. ELLIOT SMITH ON

missural area. It forms a broad tract lying in front of the lamina terminalis (l.t.), which

contains the anterior commissure : it extends forward to become continuous with the

mesial surface of the olfactory peduncle; it is separated above from the pallium by the

precommissural vestige of tlie hippocampus {v.h.'), and below it extends into continuity

with the tuberculum olfactorium. The dorso-caudal angle of the paracommissural body

has been drawn upward and backward as a long pomted process [ji'), which fills up the

gap between the psalteriurn {j>s.) and corpus callosum {c.c). Tliis process is somewhat

stretched, and is the homologue of the septum lucidum of human anatomy. With the

corresponding lamina of the other hemispliere it encloses a narrow median slit — the

cavum septi, which opens forward and downward. The only important difference in the

Myrmecoijhagidce (fig. 23 A) is that the "septal" part {p.') of the paracommissural body

has been stretched to a mucii greater extent.

In the Armadillos (fig. 23 C) there is practically no septal part of the paracommissural

body.

In the Pangolins the condition most nearly approaches that of the Sloths.

The Pallium.

It is convenient for descriptive pui-poses to associate together all the surface-areas

which we have so far discussed — bulbus and pedunctiliis olfactorins, tuberculum

otfo.ctorium, lobus lyyriformis, lobus perforatus, hij^pocamjms, and area prcccommissuralis

— in contradistinction to the rest of the surface of the hemisphere, \\ hich it is customary

to call 2)allium..

The histological structure and the morphological relations of each of the structures

which have just been enumerated are quite distinct, and present little, if anything, in

common to those of any of the other areas. But while they present so little in common

they are clearly distinguished from the rest of the cortex or pallium by the fact that they

are phy logon etically older, and at the dawn of the mammalian epocli had reached the

height of their histological difTerentiation and morphological importance. The pallium,

on the other hand, is phylogenetically quite recent, seeing that it can be first definitely

recognized as a very insignificant element in the cerebral hemisphere of rej)tiles. In the

Mammalia for the first time it develops its distinctive features, and continues to increase

in morphological importance and in histological elaboration. There is, therefore, a

very clear line of demarcation between the behaviour of the pallium attd the rest of the

sui'face of the brain which deserves to he clearly i*eflected in any system of nomenclature

Avhich we may adopt. From the fact that all the surface-areas, apart from the pallium,

are more or less intimately associated with the olfactoiy apparatus, it has become

customary to apply the term " rhlnencephalon " to this group of surface-areas. Tliis

application of tlie term " rhinencephalon " was suggested by Sir William Turner*,

although at that time the exact limits of the region — more especially with regard to the

precoii missural area — could not be mapped out. The suggestion of Schtifert to include

* AV. Turner, op. ril., ' Journal of Anatomy and rbysiology,' voL xxv. 1890.

t E. A. Schafer, Quain's 'Anatomy,' 10th cd. vol. iii. part 1, ISO'.i. p. IGU.

THE BUMS IN THE EDENTATA. 325-

the gyrus fornicatus in the rhinencephalon, in conformity with Broca's idea of a limbic

lobe, would, if adoj^ted, destroy the whole value of the term " rhinencephalon " as a

contradistinction to the term " pallium."

In employing the term rhiuencejihalon we must always lieav in mind that this

heterogeneous collection of siu'face-areas is not exclusively a " smell-brain," but that

the association of all these parts with the olfactory ai)paratus is much more intimate

than it is with any other sensory organs. This will explain the apparently paradoxical

statement that smell-less animals, like certain Cetacea, possess a " smell-brain " or

rhinencejDhalon, since the pyriform lobe and hippocampus do not entirely vanish in such

animals.

The pallium is the j)rogressive part of the cerebral hemisphere, and therefore the

region to Avhich we must attach most importance in the study of the mammalian brain.

Por in the lowest mammal the rhinencephalon has already reached as high a stage in

the evolutionary process as it ever will reach, and its essential features change but little

in mammals. The slight change that does occiu' is princij)ally a process of retrogression

in the more highly-organized members.

In the following description I have departed from the usual custom by employing the

term " sulcus " lor all the pallial fui-rows instead of the more usual term " fissure,"

not only because the former is a much more acciu'ate name, but also in order to introduce

a distinction between the strictly intrapallial furrows and the pallial boundaries, which

we still call " rhinal Jissu/-e," " hqjpocampal fissure," and " callosal fissure." To this

usual distinction the only exception will be made in the case of the Sylvian fissure,

which in its fully-developed form deserves the name " fissure." The mesial sm-face of

the pallium presents much greater ujiiformity in the arrangement of its sulci than

the cranial surfaces, and hence w e may preferably begin an examination of the pallium

in this reoion.

Upon the inner aspect of the hemisphere of Orycteropus the pallium forms a broad

strip of cortex which extends from the corpus callosum to the dorsal edge of the

hemisphere. This strip of pallium bends downward in front of the corpus callosum, and

becomes continuous along an ill-defined line with the precommissural area. Behind the

corpus callosum it bends downward and becomes continuous with the pyriform lobe.

The whole extent of this strip of pallium is divided into two ajjproximately equal areas,

a central or circumcallosal and a peripheral or marginal respectively, by a single deep

and well-defined sulcus (fig. 4). This sulcus, which we may at present distinguish as a,

begins posteriorly in close proximity to the caudal extremity of the rhiual fissure : that

is, at the extreme ventral Hmit of the mesial pallium. As it ascends it follows a coiu'se

parallel to the peripheral margin of the hemisphere, and bends forward midway between

the corpus callosum and the upper edge of the hemisphere vintil it I'eaches the anterior j)ole ;

still following its course parallel to the peripheral margin, it bends downward in front,

then after a short course suddenly bends again upward and backward, I. e. jjarallel to

the palho-precommissural junction, and ultimately terminates in a triangular depression

formed by the opening up of the anterior extremity of the callosal fissure. From the

antero- superior bending of this sulcus one or two small but deep branches are usually

SECOND SERIES. — ZOOLOGY, VOL. VII. 45

826 DE. G. ELLIOT SMITH ON

given off, \^ liicli are probably the expression of a puckering of the cortex at the seat of

flexure.

The posterior ascending part of the sulcus is A^ery deep, and indents the whole

thickness of the cortex, i. e. is a " complete fissure.'" The possible significance of this

observation will be discussed later.

The arrangement of sulci upon the mesial surface of the hemisphere in 3fi/rmecophaga

has been well represented by Forbes*. The extensive sulcus a of Orijcteropus is

represented by an analogous arrangement of three independent sulci: — a posterior

vertical {cm" of Forbes), Avhich we may distinguish as a' ; a longitudinal {cm of Forbes),

which we may call a" ; and an oblique anterior {cm of Forbes), which we may call a'".

The longitudinal sulcus (a") extends beyond the corpus callosum at each end, and sejoarates

the supracallosal pallium into t^^o longitudinal strips.

The po.sterior vertical sulcus («') appears to l)e much more extensive than the cor-

responding 2)art of the sulcus a in OriicteropHS. This apparent ditference serves to

accentuate the constant relationship which the sulcus a maintains to the fissiira rliinalis.

In Ilp'mecophaga the rhinal fissure terminates at the ventral border instead of high

up on the posterior border of the hemisphere as it does in Orycteropus, and the sulcus a'

descends to the ventral limit of the pallium, i. e. in close proximity to the fissura

rhinalis.

In Tamandiia there is no definite sulcus representing the a scries of ITi/rmecopha(ja,hxiii

merely three deep pit-like depressions, which are probably the rudiments of the cor-

responding three sulci in the Great Ant-eater. The sulcus a! is represented by a short

deep sulcus, merely 3 mm. long, which rises as high as the level of the splenium of the

corpus callosum. The sulcus a"' is represented by a deeply-incised triangular depression

a short distance in front of the genu of the corpus callosum. Above the anterior

extremity of the corpus callosum there is a short shallow furrow which is partially

analogous to the sulcus a" in the Great Ant-eater.

In the figure of the mesial surface of the brain of C//cloturus which Pouchet gives t

there is no trace of any pallial sulcus.

In the Bradi/podidce the mesial surface of the pallium presents an arrangement of

sulci which is analogous to the a-system in the Ant-eaters. In addition the mesial

extremity of a sulcus, which belongs more especially to the cranial aspect of the pallium,

extends on to this surface of the hemisphere in both Cliohtpns and Bradi/pus. This

sulcus, which we shall describe later under the designation {6, deeply notches the anterior

border of the hemisphere.

A sulcus, which we may distinguish as a, begins upon the mesial surface of the

hemisphere in Cliolcepus didaciylus, just in front of the termination of the posterior rhinal

fissure, and opposite the midpoint of the hippocampal fissiire. Its relation to the rhinal

fissure is exactly similar to the sulcus we have similarly designated in Myrmecophaga.

As it ascends it j)ursues a course which is approximately j)arallel to the upper half of

* Forbes, op. cH., Proc. Zool. Soc. Londou, 1SS2, p. 293, tig. 4.

t Pouchet, ojj. cif., torn. vi. pi. iv. fig. 4.

THE BRAIN m THE EDENTATA, 327

the hijopocampal fissure, and upon reaching the dorsal part of the hemisphere it does

not hend forward but continues its course as far as the dorso-posterior corner of the

hemisphere, where it ceases just before reaching the dorsal surface of the hemisphere.

In the right hemisphere this sulcus just crosses the upper edge to reach the cranial

surface. In his description of the brain of Cholcepus Hoffmanni Turner says * that this

sulcus, which he does not name, extends on to the cranial surface above. Flower f does

not represent any sulcus corresjjondiog to a! in his specimen of Cholcepus dklacti/lus.

In my young specimen of Bradijpus trldactylHS there is a very well-developed sulcus a',

which presents an arrangement exactly analogous to that which Turner has described in

Chola-pus Hoffmanni. It begins below just in front of the rhinal fissure, and ascends

vertically ; in its upward course it is placed upon the caudal rather than ujion the mesial

aspect of the hemisphere, as was the case in Cholaqjus, and crosses the postero-superior

border of the hemisphere at a distance of about 3 mm. from the interhemisplieral cleft ;

it, or more strictly a sulcus y with Avhich it is in uninterrupted communication, extends

forward for a distance of 10 mm. on the dorsal or cranial surface of the hemisphere (left).

On the right hemisphere of this brain the sulcus 7, w'hich is in continuity with a', is

much shorter, while in the brain of Bradi/pKS in the College of Surgeons this sulcus y

extends for more than half the length of the hemisphere.

In the brain of Cholapus a longitudinal sulcus divides tlie area of j)alliuni which lies

above the corpus callosum into two horizontal bands, of which the lower is slightly the

narrower. In my specimen of Cholapus dldactylus this sulcus, which we may call a",

begins slightly in front of the corpus callosum and terminates close to the ujiper

extremity of the sulcus a' by bifvircating so as to form a short vertical sulcus parallel

to 05'. In Flower's specimen of the same species the sulcus a'' begins slightly further

forward and extends considerably further backward before it ends simply without

bifu.rcating. In Turner's specimen of Hoffmann's Sloth this sulcus, which Turner calls

by Krueg's designation of '' splenialls" begins far forward and with a bifurcated

extremity ; posteriorly it bends downward into a direction parallel to the sulcus a', and,

according to Tu.rner, is " apparently continuous with the hippocampal fissure." Sucli

apparent junctions between the hippocamjial and other fissures are of absolutely no

importance, because the ftssiu-a hipjJOCciDipl is quite sul generis, and of a nature entireh-

diff'erent from all other fissures or sulci.

In my specimen of Bradypus the sulcus a" begins far forward in a bifurcated extremity

in much the same manner as it does in Turner's specimen of Cholcepus Hoffmanni. In

the right hemisphere it ends simply at the posterior extremity, but in the left hemisphere

there is a slight bifurcation, and in addition a small independent vertical sulcus midway

between the adjacent extremities of a and a".

In all the specimens representing the brains of Sloths we find a well-defined family

type in the mode of disposition of the mesial surface of the jmllium.

Among aU the Armadillos we find some arrangement of sulci analogous to the series a,

except in Chlamydop)horus, which, like Ci/cloturus, has a smooth pallium.

* Turner, op. cit., Journal of Anat. & Physiol, vol. xxv. p. 122. f Flower, 021. cit., Phil. Trans. 1865, fig. 5.

45*

528 DE. G. ELLIOT SMITH ON

In Dasypus sexcinctus and Dasyptis villosus there is a sulcus wbich we may refer to as

simply a. This consists of a small slightly arched sulcus, about 10 mm. long, which

jmprints the pallium about midway between the corpus callosum and the superior

border in sucli a manner that the centre of the arc is placed above the prominent

splenium of the corpvis callosum.

In Xenurus the sulcus a is much more extensive, and exhibits a jieculiar resemblance

to the fissure a in Ori/cteropiis, excepting that it lacks the posterior descending i^axi,

which we have called a' in Ilyrmecophaga and the Bradypodidse.

It is not improbable, however, that this defect is more apparent than real. In

speaking of MyrmecojjJiaga we had occasion to point out how much lower the sulcus a

descends in this form than the corresponding part of the sulcus a does in Orycteropiis,

and we associated this with the fact that the sulcus a presents a constant relationship to

the rhinal fissure, which is placed higher up on the cerebral surface in the latter. The

rhinal fissure is placed much higher still in the Armadillos, and hence it is not

improbable that the apparently incomplete sulcus a in Xenurus may be analogous to the

whole of the extensive sulcus a in Orycteropus.

In 3£anis, Pouchet * has figured an extensive longitudinal sulcvis analogous to the

sulcus a" in the Bradypodidse and Myrmecophaga. It is considerably longer than the

•corpus callosum, but quite simple. More recently Max Weber has given an excellent

figure of the mesial surface of the brain of Manis f , in which he represents under the

title "fssura sjdenialis " a longitudinal sulcus which extends the greater part of the

length of the mesial surface, and ends in front in a T-shape. In his figure there is a

faint line proceeding from the neighbourhood of the hippocampal fissure around the

posterior margin of the hemisphere on to the dorsal surface of this in a manner

similar to the sulcus u in Bradypus. There is, however, no mention of any such

sulcus in his description. Moreover, Ziehen, who has recently examined the brains

of four representatives of this genus, makes no mention of any such sulcus. He simply

states J that in Manis he found aJ/ssKva splenialis 15 mm. long, Avhich extended further

forward than the genu of the corpus callosum, and ended in a T-shape, 4*5 mm. from

the frontal pole.

The specimen of Manis to which I had access in the College of Surgeons j)resented on

the mesial surface a sulcus exactly resembling that which Weber figures and describes

under the name " fssura splenutlis."

Before passing on to the consideration of the cranial surface of the pallium we may

briefly consider, in the light of the imperfect data at our command, the significance of

this a-system of sulci, which in some form or other is present in all the heterogeneous

representatives of this order, with the exception of the smooth-brained Chlamydophorus

and Cycloturus.

If we examine the mesial surface of the brain of the Sheep {Ocis aries) we shall find a

I'learly-defined series of sulci presenting an arrangement analogous to the a series in the

* Pouehet, op. cit., torn. vi. pi. iv. fig. 10. t Max Weber, Zool. Ergebnisse, ii. tab. ix. lig. 69.

t Ziehen, ' Das CcntraluerTCiis^vstem tier Monotremcn und Marsupialicr,' Jena, 1897. p. 156.

THE BRAIN IN THE EDENTATA. 329

Edentata. We find a deep sulcus beginning just in front of the termination of the

hinal fissure, and following a course upward and then forward, pai'allel to the corpus

callosum. Before reaching quite as far as the genu this deep sulcus stops as such,

but it may be continued as a shallow furrow obliquely upward on the dorsal surface.

To this Krueg has applied the name ^'fssura splenialis,'" from its relation to the splenium

corj)oris callosi *. An independent sulcus pursues a course parallel to the anterior

extremity or gemt of the corpus callosum, and is hence known as the fssura geii/mlls.

In the important memoir of Krueg to which reference has just been made, the

presence and essential uniformity in the arrangement of this splenial sulcus in all the

Ungulata is clearly demonstrated by means of a beautiful series of illustrations and a

lucid description. Two years later the same investigator earned our further gratitude

by showing, in the same clear manner, the existence of an analogous sulcus in a large

series of other mammals, including the important order of Carnivoraf.

From these valuable series of observations we learn that in a very considerable

number of widely-separated mammals we find a constant arrangement of sulci cor-

responding to those which we have called «' and a" in Myrmecophaxja, and which

together form a feature for which Krueg has introduced the term fissura splenialis.

We also learn that a genual sulcus surrounds the anterior extremity of the corpus

callosum, but its shallowness and inconstancy point to the fact that it is of considerably

less importance than the splenial sulcus.

The high importance of the splenial sulcus is shown not only by its depth, its constancy,

and its well-defined features, but also by the fact that it is the first pallial fissure to make

its appearance in the Cat and probably also in the Sheep %. In the foetal Cat it begins

as a small arcuate sulcus behind the corpus callosum, which is analogous to the permanent

condition of this sulcus in Dasj/pus ^. As the hemisphere grows, the sulcus splenialis

extends forward. In the develo^wuent of this sulcus in the Edentata it is highly probable

that a similar mode of development would be found in Myrmecophaga and Orycteropjus

for the posterior vertical part of the sulcus which we have called a! is deeper than the

rest, and in Orycteropus, if not in others, it is " complete." It is this postero- ventral

part of the sulcus, m.oreover, which is the most constant. We have already had

occasion to observe the constancy of its relation to the rhinal fissure not only in

Orycterop'us and Myrmecophaga, but also in the JBradypodldcc and possibly in the

Dasypodidcs.

In many families of Marsupials we find a sulcus upon the mesial surface of the hemi-

sphere, which presents the typical relationship to the fissura rhinalls which characterizes

the sulcus splenialis. In many Marsupials (e. g. Phascolarctos) this sulcus,is quite short,

and is confined to the situation corresponding to that in which the early splenial sulcus

* Julius Krueg, " Ueber die Furchung der Grossliirnrinde der Ungulateu," Zeitsch. f. wiss. Zool. Bd. sxxi.

p. 308.

t Julius Krueg, " Ueber die Furehung auf der Grossliirurinde der Zonoplaccnlalen Siiugethiere," Zeitseh. f. wiss.

Zoologie, Bd. 3xsiii.

+ Vide Krueg, o/j. cit., Zeitsch. f. wiss. Zoologie, Bd. xxxi. & xxxiii.

§ Vide Krueg, op. cit., Bd. xxxiii. Taf. xxxiv.

330 DE. G. ELLIOT SMITH ON

first makes its apjiearance in the kitten's brain. But in other Marsupials (e. g. Macroptis,

Thylacinus) the sulcus extends up^\'ar(;Is, and frequently crosses the ujDper border to

reach the dorsal surface of the hemisphere.

In the larger Chiroptera we find a very extensive and fully-developed splenial sulcus

in a brain which lacks a genual fissure. Turner has figured it in Cynonycteris collaris

and Pteropus medius *. I have examined and found practically the same arrangement

in Pterojjus poliocejihalus.

There is a general tendency, therefore, in most of the mammalian orders to the

formation of a definite splenial sulcus upon the mesial surface of the hemisjihere. We

find this tendency clearly expressed in the Edentata as well as in the Marsupialia,

Ungulata, Cetacea, Carnivora, and Chiroptera. It is therefore the expression of a very

general tendency among the Mammalia, and the fact that this fissure develops upon

parallel lines in the different families of Edentates must not be considered as an indica

tion of their mutual afiinity, but rather of their wider kinship with the general body of

mammals. In the Monotremata, or rather in Echidna, which alone of the two genera

possesses a convoluted brain, we find no definite splenial sulcus, and this absence seems

rather to accentuate the closer interrelationship of the other mammals, in which the sulcus

in question is never lacking in a convoluted brain.

If we examine the brain in the large series of mammals which possess some representa-

tive of this sulcus, we shall find in many and very diverse orders an extensive and

regularly-arched sulcus extending forward in a " genual " manner such as we have

met in Orycterojms and Xenurus. We have already noted the existence of such a

splenial sulcus in Pteropus and other large Chiroptera; in many Cetacea we find a

similarly extensive and regularly arcuate splenial sulcus, as for instance Turner's figure

of BalcBHoptera f shows ; we find the same arrangement in many Ungulata, as for

instance in Eqmis, and among the Carnivora we find an admirable example of the same

arrangement in Proteles cristatus +. In the latter brain Krueg distinguishes the anterior

part of the large arcuate sulcus as genual, and the rest of the fissure as splenial. The

inconstancy and variability of the genual sulcus show^ that it is of very slight morpho-

logical importance, and in many cases it may be merely a mechanical product. The

splenial sulcus, howevei% is a much more definite and constant feature, and is obviously of

great morphological significance. But the most constant part of the splenial sulcus is

that portion which lies behind and below the splenium of the corj)vis callosum. In a

series of mammalian brains this part of the sulcus is absolutely constant in all hemispheres

which have any pallial sulci whatever ; it is also the deepest part of the sulcus ; it is, as

we have seen in the Cat, the first part of the sulcus to appear in ontogeny, and from

comparative studies we find that many brains (e. g. Phascolaretos) which possess no other

true pallial sulci have a small splenial sulcus in this situation. The posterior or ventral

part of the splenial sulcus is the constant element, but the anterior part is much more

* Turner, op. cit., Journal of Anatomy and Physiology, vol. sxv.

t Fig. 33.

t W. H. Flower, " Anatomy of rrotdcs," Proc. Zoo), f-'oc. London. lS6i>, fig. 4.

THE BRAIN IN THE EDENTATA. 331

Tariable, often insignificant or entirely lacking', and altogether of quite minor morplio-

logical imjiortance. In the Sloths we have seen that these two elements in the splenial

sulcus, the constant element («') and the varial)le element (a"), ai'e quite distinct the one

from the other.

If we turn from the consideration of the splenial sulcus in the majority of mammals to

its condition in the Primates, we are surprised to find that the sulcus which is usually

described as the " splenial " is lacking in its most essential part, namely in that retro-

splenial j^ortion which we have just learned to regard as the only constant part of the

sulcus. Thus Tm-ner *, in common with many other writers, uses the term " splenial

fissure "as synonymous with " calloso-marginal fissure," tacitly implying a homology

which is extremely questionable. We are quite prepared to admit that the calloso-

marginal fissure of Man and the other Primates may represent the inconstant and mor-

phologically unimportant {a") element of the splenial sulcus, but it obviously doas not

represent the whole, nor in fact the most important part, of that fissure. Moreover, it

seems highly improbable that the most constant sulcus of the pallium throughout the

Mammalia, the earliest fissure to make its appearance in development and often the only

" complete " sulcvis present, should entirely vanish in the Primates.

One of the first, if not actually the earliest, sulci to make its appearance in the

development of the human pallium is a short, oblique, and very deep farrow a short

distance behind and slightly below the splenium of the corpus callosum. This important

sulcus has been called bv Professor Cumiin2:bani f the " anterior calcarine.'" The features

of this sulcus in its earliest stage are so analogous to the earliest stage of the " splenial

fissure " of Krueg in the developing brain in the Cat that the question of their homology

naturally suggests itself. When we remember that the anterior calcarine sulcus is a

complete and a very constant sulcus, of obviously great morphological importance, and

that it makes its appearance in a situation analogous to that occupied in most mammals

other than the Primates by a very constant sulcus Avhich is sometimes complete and of

undoubted morphological importance, there is sufficient evidence to justify us in

suggesting, as a tentative working hypothesis, the morphological identity of the two

structures, i. e. of the anterior calcarine fissure of Primates with the essential or caudal

part of the s]jJ en ial fissure of most other mammals. Por it seems to me unlikely that such

a deeply-imprinted feature, which, almost alone of all the pallial fissures, tends to make

its appearance in all the mammalian orders, except the specialized Monotremes, should

suddenly disappear in the Primates without leaving any trace behind. If we glance at

such a brain as that of Lemur nigrifrons, which Turner has reproduced % from a memoir

of Plower, the resemblance of the calcarine fissure to the a' element of the splenial sulcus

is indeed striking, since the sulcus in question presents the characteristic relationship to

the rhinal fissure. In Man and the Man-like Apes the similarity is not so striking, not

* Turner, o^;. dl., Journal of Anatomy and Ph) siolog3% vol. xxv. p. 143.

t D. J. Cunningham, " The Surface Anatomy of the Primate Cerebrum," Cunningham Memoirs of the Royal

Irish Academy, No. vii., 1892.

% Turner, op. a'(., Journal of Anatomy and Physiology, vol. xxv. fig. 38.

332 DE. G. ELLIOT SMITH ON

only because the rhinal fissure has vanished, but also because the " calcarine fissure "

appears to branch backward and upward into two other sulci, the posterior calcarine (in

Man) and the parieto-occipital respectively. But, as Cunningham remarks *, these latter

fissures are of v^astly less morphological importance.

In many of the Carnivora we see the beginning of that backward extension of the

occipital pole of the hemisphere wbich produces the occipital " lobe " of the Primates, and

as a result of tliis growth the "calcarine limb" of the splenial sulcus (or in other words

the a element) becomes acutely bent on the " culloso-marg'mal limb " or a" element

of the splenial sulcus. It is not difiicult to understand that the continuation of

such a process results in the separation of the calcarine from the less important and

more unstable calloso-marginal element in the Primates. In this manner we wovJd

have produced the extensive calcarine sulcus which Cunningham describes f in the

Anthropoid Apes.

[Since the above was written I have met Avith the following interesting remarks, which

lend considerable support to the thesis I have independently put forward. In discussing

the question " whether we are justified in saying that quadrupeds have a far less

developed occipital lobe than the Primates," Professor Moriz Benedikt says % : —

" The first argument for this view is that the quadrupedal classes of animals have no

occipital fissure. This statement appears to me to be contrary to the real condition.

The stem of the fork-shaped occipital fissure (the combined calcarine and parieto-occipital)

of Man is characterized as an arc with its convexity directed towards the posterior j)ole,

and it surrounds that part of the gyrus fornicatus which limits the splenium corporis

callosi. When we search after this fissure in a great number of gyrencephalic animals,

we find it, but only in connection with the fissura calloso-marginalis.

" It may be remarked that in certain anomalous human brains the fissura calloso-

marginalis does not come to an end, as in typical cases, by being curved upwards, so as

to form the posterior limit of the paracentral gyrus of Betz. It is continued towards the

posterior part, forms a limit between the prsecuneal gyrus and the corresponding part of

the gyrus fornicatus, and unites with the stem of the fork-shaped fissure in such a manner

that this stem becomes the most posterior part of the calloso-marginal fissure."

This is most important and valuable corroborative evidence ; for what Benedikt calls

"the stem of the fork-shaped fissure" is the same sulcus which Cunningham caUs

" anterior calcarine " and which I have already regarded as the caudal extremity of the

splenial sulcus. Speaking of Benedikt's earlier expression of this view §, Professor

Cunningham says, " Upon his further statement that the calcarine fissure is also developed

in brains below the Primates we are not in a position at present to oifer an opinion " || .

* Cunningham, op. cit., Cunningham Memoirs, p. 41.

t Cunningham Memoirs, oj}. cit.

+ Moriz Benedikt, " Some Points on the iSurface-Anatomy of the Brain, " Journal of Anatomy and Physiology,

sxv. p. 211.

§ Moriz Benedikt, •' Der Hinterhaupts-Lappen der Saugethiere," Centralbl. f. d. med. Wissensch., 1877, No. 10.

II D. J. Cunningham, " Complete Fissures of the Human Cerebrum," Journal of Anatomy and Physiology, vol. xxiv.

p. 343.

THE BEAIX IN THE EDENTATA. 333

It seems to me that the su;^gestive mass of evidence in favour of the view that the

" retro-limbic tissure " of Quadrupeds is tlie homologue of the calcarine sulcus of Primates

cannot be lightly gainsaid.]

The great bulk of the litei'ature relating to the brain in the Edentata is mainly con-

cerned with the cranial aspect of the pallium. But altliough this is the case, the

information to be culled from a study of this mass of descriptive matter is of a very

imperfect and in many ways an unsatisfactory nature, for our methods and ultimate

aims in investigating the anatomy of the brain are now vastly different from those

which inspired the authors of the records which we find so disappointing in their

insufficiency. It would therefore be hardly justifiable to enter into a serious discussion

of many aspects of tlie study of the surface of the brain which take a foremost place

in the memoirs to which reference will be made.

It will conduce to clearness in the description of the surface of the pallium in this order

if we begin Avith the. consideration of Myrmecophaga, in which the fissures very clearly

conform to a Avell-recognized type.

In the memoir of Gervais * we iind excellent representations of the conformation of

the pallium in a specimen of Myrmecophacja, as well as a figure of a cranial cast of

another specimen. In the more recent memoir of Forbes f Ave find some very useful

semi-diagrammatic figures of the brain in two specimens of Ilynneeojjhaga. My

observations were made upon two specimens in the galleries of the Iloval Colleo^e of

Surgeons ; but, as one of these brains AA'as still clothed Avith its membranes, practically only

one Avas available for examination. A partially-dissected specimen of the brain of

Myrmecophaga in the stores of the College enabled me to investigate many pioints in its

internal anatomy. Figure 7 represents the left lateral aspect of one of the brains of

Jlyrmecophaga in the College of Surgeons, and may serve as a type upon Avhich to base

our description.

The A^entral boundary of the pallium is formed by the rhinal fissure, Avhich consists of

an approximately parallel anterior segment passing by a regular arcuate course

directly into the posterior rhinal segment. The latter forms an angle of about 120^ with

the former, and hence the posterior part of the pallium descends to the base of the brain

as a large dependent process behind the pyriform lobe. Above the point of junction of

the anterior and posterior rhiual fissures Ave find a triangular depressed area of pallium,

Avhicli we may distinguish as the fossa Sylvii. Its posterior border is formed by a

vertical lip which begins below at about the mid-point of the oblique posterior rhinal fissure.

As it ascends this lip diverges from the lip formed by the pyriform lobe at the posterior

rhiual fissure, and AA-hen it has reached a point about 7 mm. from the dorsal surface of

the hemisphere (vicAved in profile) it curves backward for a short distance and terminates

suddenly. Thus Ave find the fossa Sylcii limited below and behind by two prominent

arcuate lips, the convexities of Avhich face one another. These lips meet below, but above

and in front they are widely separated. In this broad interval the depressed area of

* P. Gervais, op. cit. pi. i. figs. 3, 3a, and '3h, and pi. ii. fig. 3.

t W. A. Forbes, op. cit., Proc. Zool. Soc. London, 1882.

SECOND SERIES. — ZOOLOGY, VOL. VII. 46

334 DE. G. ELLIOT SMITH ON

pallium gradually slopes up to the general level of the pallium without any definite lip

to separate it from the rest of the surface. Toward the anterior extremity of the fossa,

however, an ill-defined ridge of cortex or lip makes its ajipearance just above and parallel

to the anterior rhinal fissure. In other words, a hoi-izontal depression about 1"5 mm.

broad is found immediately above the posterior half of the anterior rliinal fissure ; from

the anterior extremity of this depression a sulcus begins and extends obliquely upward

and forward toward the antero-superior corner of the hemisphere, where it terminates at

a point about 2 mm. from the apex and an equal distance from the mesial border of the

pallium. We may distinguish this sulcus by the designation /3. Upon the right

hemisphere of the same brain the fossa Si/lvii presents features which closely resemble those

upon the left hemisphere, and the sulcus 3 arises in the same manner, but does not extend

so near to the mesial plane. But in addition we find in this hemisphere a small oblique

sulcus, 9 mm. long, upon the dorsal aspect of the apex, just in front of the termination of the

sulcus /3. In the brain which Gervais figures the two hemispheres appear to be perfectly

symmetrical so far as the fossa Si/lvil and the sulcus j3 are concerned. The lips which

limit the fossa Si/lvil appear to be more prominent, and in addition there seems to be a

definite though faint lip bounding ih.G. fossa Si/lvii in front. As a result of the existence

of this anterior lip, the upper extremity of the fossa Si/lvii seems to be converted into a

definite fissm-e, which arches obliquely upward and backward and then pursues a course

of about 10 mm. in the caudal direction parallel to the great interhemispheral cleft

(vide Gervais, pi. i. figs. 3 and 3 a). So far as we can judge from Gervais's figures, the

sulcus /3 is quite independent of the fossa Sylvii and the fissura rhinalis, but begins at a

distance of 2 mm. above the anterior rhinal fissure and extends obliquely forward to

cross on to the mesial surface of the hemisphere at a distance of about 4'5 mm. from the

apex of the pallium. Unlike the condition in our type-specimen, the sulcus /3 appears to

be symmetrical in the two hemispheres. Forbes represents the sulcus /3 in one of his

specimens extending into continuity Avith the rhinal fissure ; but he remarks that the

area in front of the sulcus /3 (which, in accordance witii the extraordinary suggestion of

Broca, he calls the " frontal lobe ") is connected to the fodsa Sylvii (Broca's " lobule

sous-sylvien ") by a small, sometimes deep, bridging fold.

At a distance of about 6 mm. from the mesial plane there is, upon the dorsal surface

of each hemisphere, a longitudinal sulcus which we may distinguish as y. The anterior

extreaiity bends obliquely outward and downward, and is 13 mm. distant from the apex

of the hemisphere. The posterior extremity approaches quite close to the posterior

border of the hemisphere, and bends outward for a short distance imrallel to it.

In the specimen figured by Gervais the anterior extremity of this sulcus does not bend

laterally, but otherwise it agrees Avith our type-specimen. In all cases the sulcus 7

approaches very close to the sulcus f3, but without actually joining it.

The broad elliptical area which lies between the posterior lip of the ybss« ^_y/»w and

the posterior margin of the hemisphere is divided into two approximately equal j^arts by

a deep vertical sulcus, whicli begins above at a point about 1; mm. (viewed in profile)

below the sulcus 7, and ends below at about an equal distance above the ventral margin

of the hemisphere. Tiiis sulcus, which we may call I, is approximately symmetrical

THE BKAIN IN THE EDENTATA. 335

upon the two liemispheres. From the postero-ventral corner of the hemisphere a

shallow furrow ascends upon the left hemisphere for three or four millimetres, and upon

the Yis;ht hemisphere a more definite sulcus in the corresponding place. We may call

this the sulcus e.

Upon the right hemispliere of our type-specimen there is a faint trace of a vertical

furrow midway between the sulcus S and the fossa Sylvil. We may refer to this as the

sulcus n. Thei'e is no sign of it upon the left hemisphere.

In the figure of the lateral aspect of the brain which Gervais gives there are two

extensive vertical sulci upon the postero-ventral area of ])allium, and a trace of a third.

The exact homologies of these sulci are somewhat doubtful. It is possible that the most

caudal represents an exceptionally well-developed sulcus e, and the more anterior the

sulcus 5.

Upon the left hemisphere of our type, as Avell as in the specimens figured by Gervais

and For]:)es, there is a shallow horizontal furrow midway between the anterior part of

the sulcus -y and the narrow tapering extremity of the fossa Sylcil. This may be

distinguished as S'.

If we compare the arrangement of sulci upon the cranial surface of the hemisphere of

Myrmecophaga with the principal and more constant fissures which are found upon the

pallium in the Carnivora, we must admit that the resemblance is so close that it suggests

somethins' more than a mere coincidence. The similarity is so striking? that we do not

hesitate to compare one by one the sulci of Myrmecophaga, Avith sulci which are

obviously homologous in almost any Carnivore. The resemblance is perhaps more

striking in the case of the small Carnivores, because soaallness implies a simplicity in the

arrangement of the sulci. In the lai'ger Carnivores the pattern becomes complicated by

the introduction of numerous subsidiary and morphologically unimportant sulci. But

in such a brain as that of Proteles, of which Flower has provided its with admirable

illustrations*, we find hemispheres devoid of all the subsidiary sulci and only the

important sulci remaining. In such a type we find the homologues of the sulci of

Myrmecophaga preserved, while most of those not represented in the brain of the

Ant-eater are also lacking in the small Carnivore. For purposes of comparison, however,

I shall refer to the better-known l)rain of the Dog, of which many admirable descriptions

are aAailablc.

In the Dog we find a fissure arising from the point of junction of the anterior and

posterior rhinal fissures, and extending obliquely upward and backward. It is customary

among writers to call this the " Sylvian fissure," but Ave must accept this term, which is

borrowed from human anatomy, with some reservation. The so-called Sylvian fissure of

of the Dog's brain is rather an early expression of those factors Avhich, in the human

bi"ain, produce large folds of pallium that overlap an intermediate area of sunken

cortex, and by their meeting form a fissure.

The so-called Sylvian fissure in the Carnivora ought to be regarded as analogous

rather than strictly Jiomologous to the true or human Sylvian fissure. In the Carnivora

* W. H. Flower, " Anatomy of Proteles," Proc. Zool. Soc. Londcn, 1869.

46*

336 DE- (i- ELLIOT SMITH ON

the downward beading of the posterior part of the pallium, which results in the

production of the large post-rhinal tongue-like process, necessarilj' implies a restriction

to, or rather a tension on, the growing pallium at the seat of the bending. It is not

unlikely that this flexure produces a kink — the fossa Sylvil — at the place of bending,

and that the tension of the growing cortex in this region is relieved by the outgrowtli of

lips of iiallium at the margins of the kink. In the human brain both of these factors

become greatly exaggerated, and a much larger area becomes involved, but the process

is probably analogous to that which takes place in the Dog.

In the Dog's brain the Sylvian fissure is formed by the meeting of two lips of the pallium,

\\hich extend toward their place of meeting by overlapping a depressed area of cortex.

If these lips be cut away, we expose a triangular depressed ai'ea of exactly the same

shape as the fossa Sylvih in Ilyrmecophaga. The anatomy of this region of the Dog's

brain has been most lucidly demonstrated by Dr. Langley *. In the dissection

represented in his ligvire 16 we find a triangular depressed area ov fossa Sijlvii (which

he calls the " Island of Ueil "), limited on the ventral side by tlie convex junction of the

two parts of the rhinal fissure ; on the caudal side bounded by an almost vertical

limiting furrow, which is formed by the outgrowth of overhanging lip (which has been

cut away in the dissection) ; and bounded in front and dorsally by an oblique furrow

which is formed by the overhanging anterior lip. The superior limiting furrow joins

the posterior limiting furrow above, and the two are analogous to the sulcus Umitans

insidce of the human brain. It is also noteworthy that a narrow horizontal depression

extends forward from the fossa Si/Uni above the anterior rhinal fissure, just as we find in

Myrmecophaga, but in the Dog this depression is overhung by the anterior extremity of

the upper Up or operculum.

Thus the representative of the sulcus /3 in the Dog's brain appears in a superficial view

to join the anterior rhinal fissure.

In Myrmecophaga there is no Sylvian fissure, even in the sense in wliicli this term is

applied to the Carnivore's brain. But we have a fossa Sylvil, which is limited posteriorly

by an operculum that has not yet overlapped the depression, and anteriorly by the very

fjiintest trace of an anterior operculum. Before we can say that a Sylvian fissure exists,

these two lips must increase considerably in size, overlap the depressed area, and

ultimately meet to form a fissure.

The exposure of the fossa Syloli in the Edentata is indicative of the small extent of

pallium as compared with the Carnivore.

The sulcus [5 is represented in the Dog by a sulcus which is called siqjraorbilal

by FloAver f and others, or ^j/r - Sylvian by Owen and others. The sulcus y is

represented in the brain of the Carnivora by a longitudinal sulcus knoflm as the

coronal or sagittal sulcus. In the Carnivora, however, the cephalic extremity of

the coronal sulcus is usually bent in the lateral direction to accommodate the crucial

sulcus, which is lacking in the Edentata. The caudal extremity of this sulcus is

* J. N. Laugley, " The Structure of the Dog's Brain," .loumal of Physiology, vol. iv. .See especially, in this

connection, pi. vii. tig. 16.

t W. H. Flower, " Anatomy of Protdes,'' Proc. Zool. Soc. Loudon, 1809, p. 479.

THE BEAIN i:*^ THE EDENTATA. 337

often bent downward, and in Mtjnnecophaga it is quite possible tbat this occasional

feature of the Carnivorous brain may occur, for in our type-specimen we find a faint

depression y" in the situation where this more extensive sulcus occurs at times in the

Dog.

The only sulcus in the post-Sylvian region of the Dog's l)rain which proseats any

constancy is one that Owen calls post-Si/lvian, while Krueg distinguishes it as posterior

supru-Syhiun. It corresponds to the sulcus S in Myrmecophaga. But in the Dog it

usually forms part of a large arc, the anterior extremity of which may possibly be

represented in Myrmecophaga by the small but constant depression S'.

In the Dog the growth of the Sylvian opercula covers up the Sylvian fossa and forms

the fissure of Sylvius, and after that has taken place the tension of further growth is

relieved by the formation of the large supra- Sylvian sulcus.

In the Dog a sulcus, which is not nearly so constant as the posterior supra-Sylvian, is

sometimes found between the latter and the Sylvian fissure. Tlie occasional furrow i; in

Myrmecophaga may represent this sulcus, which in the Dog is called the "posterior

ecto- Sylvian fissure " by Langley {op. cit.), who has modified Wilder's nomenclature.

The furrow e in Myrmecophaga finds its analogue in a sulcus of the Dog's cerebrum,

which "Wilder and others following him have called ecto-lateral.

From this brief review we liave seen that every sulcus or depression upon the pallium

of Myrmecophaga finds an analogue to correspond witli it upon the brain of the Dog.

Moreover, we find that if a large number of Dogs' brains be compared, or if we compare

the brains of a large number of different Carnivores, the constant and deepest sulci are

those which we find represented in tlie brain of the Great Ant-eater.

There is, however, one important and very significant exception to this generalization.

In the Dog, as in all Carnivores, we find a short deep sulcus extending transversely

outward from the interhemisphcral cleft near the cephalic extremity of the pallium.

This sulcus, commonly known as the crucial, is a very characteristic feature of the brain

in Carnivora, and is quite lacking in the brain of Myrmecophaga. This absence is very

significant when we recall the fact that physiological experiment has sliown that the

pallium which immediately surroimds the sulcus in the Dog is the only " excitable " or

" motor " area of the cortex. It may be that the brain of the Dog shows a marked

superiority over the brain of the Ant-eater in that the central area, which presides over

skUlcd movements, shows a sudden increase in extent, resulting in the formation of a

new sulcus, the crucial.

On the other hand, the formation of the crucial fissure may be to some extent the

expression of a general, rather than a local, increase in the extent of the pallium. For

we find in the brain of the small Carnivore Geiietta tigrina, which Mivart has described,

an absence of a true crucial sulcus, Avhereas all the sulci found in the Edentata are well

developed *. In this small and very active Carnivore there are only some shallow pits

to represent the crucial sulcus, and, as we have no reason to believe that skilled

movements are less developed in this family than in the other Carnivores, it is possible

* St. George Mivart, " Notes oii some Points iu the Anatomy of the .Elui-oidea,'' Proc. Zool. Soe. London

1S82, p. 510, fig. 11.

338 DE- G- ELLIOT SMITH ON

that tlie general growth of tlie pallium may liave some influence in the production of

the crucial sulcus.

Apart from this apparent difference in the extent of the excitable areas of the cortex,

there are other differences between the pallia in the contrasted brains.

If we compare the size of the brain in Ilyrmecophaga and Caiiis, we shall find a

striking contrast between the two organs. In his valuable monograph upon the weight

of the brain in mammals, Max Weber* gives the weight of the brain in grammes as

comjiared to the body-weight in four specimens of the Great Ant-eater as follows :—

Percentage of

Brain- Body- Braiii-woiglit

weight, ■weight. to Botly-weight.

Myrmecophmja juhuta, % 75 : 20,800 0-36%

$ 84-5:25,500 0-33%

? 87 : 23,000 0-37 7o

? 84 : 28,086 0-29%

})

From the same lists 1 select for comparison the brain-weights of four Dogs whose

body-weights approximate to those of the Ant-eaters, and exj)ress them in a similar

manner thus : —

Percentage of

Brain- Body- JJrain-weighfc

weight, weight. to Body-weight.

Canisfam.: Bernhard, 'i ] 16 : 28,000 0-41%

Canis fum. -. Sat/ax venaticiis -f- Extrarius

aquaticus ieme novtE, S I'^'T' : 27,500 0-39%

Canis faw.: ditto, S 9« = 25,000 0-39%

Can is fum. : Molonossus 95 : 2 1 ,000 0-45 %

In all of these Dogs there is a most decided superiority in the brain-weight over that

of the Ant-eaters.

The brain-weight in Dogs is exceedingly variable, as Weber's tables amply demonstrate,

but in all Dogs approaching the size of a Mijrmecophaga there is a very decided superiority

in the weight of the Dog's brain over that of the Edentata. Among otlier sj)ecies and

genera this superiority is even more striking. Thus in Cams juhatus, according to Weber,

we find a brain Aveighing IGO grms. in an animal of only 23,G00 grms., i. e. a brain

0'7 7o of the body-weight, and in Felis panlas a brain of 130 grms. in an animal of

23,820 grms., or O'Si 7o of the body-weight. On the other hand, in a Hycena striata

weighing 28,750 grms., or more than the heaviest of the four Ant-eaters, Weber found a

brain weighing nearly 81 grms., or 0-28 7^ of the body-weight. This, however, must

have been a very exceptional case, for in another specimen of the same species and of

the same sex he found a brain of 89 grms. (i. e. heavier than the brain of any of the

Ant-eaters), while the animal weighed merely 17,500 grms., thus giving a brain-weight

which is 0-508 7^ of the body-weight.

* Max Weher, " Yorstudien iiber das Hirngewicht der iSaugethicre," Separat-Abdruck aus Festschrift fiir Carl

Gegenbaur, Leipzig, 1S96.

THE BRAIN^ IN THE EDENTATA. 339

In the Dog the brain is, ronghly speaking, more than 10 \ of the body-weight heavier

tlian in the Ant-eater, taking into consideration only animals of approximately the same

size.

"We find upon examination that tlie difference in size of the brain in Mijrmecopliaga

and Cants (in animals of approximately the same size) is almost wholly a question of

the extent of the cerebral cortex.

Now in IJijrmecopluuja the rhinencephalon is both relatively and absolutely very much

more extensive than it is in Canis, and hence the disproportion between the size of the

pallium in the two brains is even greater than a comparison of the brain-weights

might lead us to imagine. It becomes an interesting question to determine what effect

this increase in extent has upon the configuration of the paUium.

I have already explained the effect of local hypertrophy of the excitable cortex in

the production of the crucial sulcus and the lateral displacement of tlie anterior ead of

tlie coronal sulcus (7). I have also shown how two definite opercula form around the

fossa Sylvii and ultimately expand so as to cover up that depressed area. In addition to

this the homologues of the sulci which the pallium of Myrmecophaga presents become

deeper and more extensive in the Dog, and large numbers of new^ sulci make their

appearance to enable the more extensive pallium to accommodate itself in a minimum

space.

Let us notice also some general results of the larger pallium. In the Ant-eater the

posterior border of the hemisphere is vertical, and the hemisphere itself entirely in front

of the cerebellum. In the Dog the general expansion of the cortex is relieved by the

caudal extension of the postero-superior part of the hemisphere over the cereliellum,

so that the posterior border becomes oblique. This l)ackward or occipital extension has

obvious effects upon the mesial surface, which need not be specifically detailed.

This occipital extension of the pallivtm in the Carnivores is analogous to the much

more pronounced growth in the caudal direction which we find in the Primates.

I have discussed at some length the points of resemblance and of contrast in these

two brains in order to explain more clearly the salient characters of the brain in the

Ant-eater. "\Ve have thus been able to estimate those features wiiich constitute the

superiority of the Dog's brain over that of the Ant-eater, and have been impressed

with the important conclusion that the two brains are built upon essentially the same

plan, or, in other words, that the same factors wliich are at work in mouldin""

the pallium in the Carnivora are fashioning the homologous part of the brain of

Myrmecophaga in the same likeness.

The significance of these facts will be considered later. At present I merely note

the resemblance. The records of any observations which have hitherto been made upon

the brain of Tamandua are of the scantiest nature. Gervais gives a figure representing

the dor.«al aspect of a cranial cast *, and Pouchet gives figures of the dorsal and lateral

aspect of the cerebral hemispheres t, but these figures are very unsatisfactory, because

they lack all detail. Even a landmark so well-defined as the rhinal fissure is repre-

sented only in a small ])art of its course.

* P. Gervais, op. cit. pi. ii. fig. 2. f G. Pouchet, op. cit. pi. v. figs. 1 & 2.

340

DE. G. ELLIOT SMITH ON

Forbes has given tis an exceedingly crude scheme of the dorsal aspect of one hemisphere

of Tamandita *. My own observations were made upon these brains, one of which had

been left to the lloyal College of Science by Professor Huxley, aud the other two are

at present in the galleries of the Eoyal College of Surgeons. To illustrate ray description

I have constructed a semischematic drawing (fig. 8) from one of the specimens in the

Collesje of Surgeons.

If we imagine an extension of the process of simplification which would be necessary

to reduce the brain of Canis to the condition of Iliirmecopliaga, so that in a smaller

braiu all the less pronounced features in the brain of the latter became eliminated, and

the more deeply-impressed characters became more faintly marked, we should gain some

idea of the appearance of the brain of Tamandna . We have seen that in Ca)iis the

faintly-marked lips which serve to denote the boundaries of the fossa Sylvii of Jlyrmeco-

2)liaga have become definite opercula which cover up the fossa Sylvii. In Tamandua

the lips entirely disappear, so that we find no trace of a fossa Sylvii, for the pallium

above the regular arc formed by the rhinal fissure is smooth. The sulcus /3, which

we have seen to correspond to the supraorbital sulcus of the Dog, is represented Ijy

Fiff. 25.

bulb, olfact.

lob. ant.

fis9. prima

lob. flooculi

medulla oblong

area A

i'" area B

area 0

Dorsal surface of braiu of Tamandua ietradacti/la. Nat. size.

a short oblique sulcus which does not apj^roach nearer than 4 mm. to the rhinal

fisssure in our type-specimen. This sulcus is constant in the six hemispheres which

I have examined, as well as in the figures of Pouchet and Forbes. It is even visible as a

depression upon the cranial cast which Gervais represents. This is the most constant

sulcus upon the cranial surface of the pallium in Tamandua. In this connection it is

not withovit interest to note that, according to Krueg f, it is one of the earliest fissures

to make its appearance in the development of the pallium in the Cat, as well as in the

Sheep and Ox.

* W. A. Forbes, q/). cit. fig. 5.

t Julius Krueg, Zeitsch. f. 'wissensch. Zool. Bd. xxxiii.

THE BEAIN I^" THE EDENTATA. 311

A sagittal sulcus (7) pursiics a course parallel to and at a distance of about 5 mm. from

the interhemispheral cleft for about the middle two fourths of the margin of the

hemisphere in our type-specimen. Just behind its caudal extremity there is another

short sulcus which probably belongs to the same series. In a second brain this sulcus

is also present in both hemispheres, but is interrupted and in parts very shallow on

the riglit side. In the third specimen the sagittal sulcus is represented in each

hemisphere merely by short sulci at the cephalic and caudal extremities of the position

which the sulcus Avould occupy. These short sulci are united by a very shallow furrow.

In Pouchct's and Forbes's illustratious continuous sagittal sulci are represented; while

in the cranial cast figured by Gervais deep coronal grooves are indicated, and each

apparently lodges a large blood-vessel.

Just below the caudal extremity of the sagittal sulcus (y) there is in our type-specimen

a shallow, almost vertical sulcus, which probably corresponds to the sulcus 0 in Ilurmeco-

fliacju. In one of the other two braios this sulcus is even more faintly marked still, but

in the third we find an exceedingly interesting condition. In this brain tliere are

indications of an arcuate sulcus resembling the suprasylvian sulcus in the Carnivora_

A sulcus begins a short distance aljove the point of junction of the anterior and posterior

rhinal fissures, and after arching upward and backward for a short distance it passes

into a shallow furrow which ciu'ves backward and vertically downward in a situation

exactly analogous to the sulcus S in MyrmecoplicKja. It seems as though this represented

a more complete arcuate or siiprasi/Jvum sulcus than is present in Ilijrmecophaya. It

may be that the depression S' in the latter represents the cephalic extremity of the arc.

Upon the left hemisjihere of this l)rain of Tamanditu we find the uj^per part of the

arcuate sulcus without the descending part.

The cranial cast of Tanmndua which Gervais has represented * is considerably larger

than any brain which I examined or of which there is any record. From this cast we

might gather that the sagittal (y) and supraorbital (/3) sulci were deeper and more

definitely maj)ped orit than they are in the brains we have examined.

In the absence of any fossa Sylvii it would have been difficult to detect in the brain of

Tamandua any resemblance to the Carnivorous type of bi-ain, but 3Iij rmecopha ga provides

for us the needful connecting-link. For, while clearly exhibiting the family type which

binds it to Tamandua, it shows us how the Sylvian fissure becomes obliterated, so that

the transition from the Carnivorous to the simple Tamandua type is easy to follow.

A notable demonstration of this resemblance is given by the developing l)raln of

Felis, which Krueg has figured f. At a ]3eriod just before the Sylvian fossa makes its

apjiearance, the configuration of the pallium of the foetal kitten presents a surprising

resemblance to the adult Tamandua, with its supraorbital (/3), sagittal (7), and suprasylvian

(g) sulci.

At the same time Tamandua demonstrates the superiority of the Carnivore's brain

For in the latter order a brain of the dimensions of that of Tamandua would certainly

* P. Gervais, op. ell. pi. ii. fig. 2.

t Julius Krueg, op. (it., Zeitsch. f, wissensch. Zool. lid. xxxiii. Taf. sxxiv.

SECOND SERIES. — ZOOLOGY, VOL. VII. 47

31.2 DR. G. ELLIOT SMITH ON

be more richly fuiTowed even than that of llyrmecophaga. We know that the pallium

increases in extent in any order with the added hulk of the animal. A Carnivore as

small as Cyclottirus would have a pallintu with as complex a pattern as the Great

Ant-eater.

I have not had an opportunity of examining- the brain of the small arboreal Ant-eater

Cycloturus, Init, judging- from the figures of Tiedemann, Pouchet, and Gervais, its

pallium must be quite smooth and devoid of sulci. The transition from Tamandua with

its shallow and faintly-marked sulci to the smooth condition is quite simple, and amply

justified by the difference in size between these two Ant-eaters.

One cannot fail to be struck by the resemblance in the configuration of the hemisphere

of Tamaiidna, and especially Cijdoturus, to the Rodent type. Moreover, the exact

shape of the corpus callosum and the behaviour of the hippocampal formation, which we

liave found so variable elsewhere, are closely reproduced in the Uodentia. When we

compare the brain in the Rodeutia with that of the Myrmecophagidse, we can confidently

afiirm that any superiority of type that may exist certainly does not favour the Rodent.

Unfortunately no collection of brain-weights is available for comparing the two

groups on the basis of relative size of brain. The solitary brain-weight of Tamandua

which Max Weber gives* is much highei- than tliat of any Rodent of approximately

the same body-weight. But a large mass of data is necessary before we can confidently

compare the two groups.

It is sufficient at present to note that there is an interesting series of transition stages

in pallial modification in the Carnivora, Myrmecophagida;, and Rodentia. But while

the evidence at our disposal conclusively shows the distinct superiority in cerebral

organization of the Carnivore over the Ant-eater, it does not permit us to say that the

latter is in any way infei-ior to the Rodent.

All the information we possess clearly and decisively points to the undoubted kinship

of the Ant-eaters with the Sloths and Armadillos. But for several reasons I propose

to consider next the pallium of the Aard-vark. From the writings of Pouchet and

Gervais one might conclude that there is a close resemblance between the brains of

Mynnecojihaga and Orycteropas. I shall demonstrate that such a belief is utterly

illusory and erroneous, and. shall discuss Orycteropzis in this place in order to show the

strong contrast between the two forms, and in tliis way to accentuate the im])ortance of

the agreement we have found between Mynnecophaga and the Carnivora.

In our brief review of the literature relating to the brain in different families of

Edentata, Ave found that practically nothing was known of the brain in the Orycteropidaj

beyond its general shape. Leuret published some observations t upon the brain of

Oi-ycteropm sixty years ago, but, acting under the mistaken idea that mammals might

be classified according to the relative richness of their cerebral convolutions, he included

in one group three such dissimilar brains as those of Orycteropus, Macropus, and

Pteropus, without giving us any information of lasting value.

* Max Weber, op. cit., Gegeubaur's ' Fe.st.schrit't,' lS9t5.

t Leuret, ' Anatomie com2)aree du Systume nerveux,' Paris, 1838.

THE BKAiX IX THE EDENTATA. 313

Writing thirty years after Leuret's original memoir, Pouehet says * tliat the Ant-eaters

form with Oryeteropus a separate group, in which we find an agreement in the arrange-

ment of the convohitions and in the general form of the brain. The same writer says

(p. 1(3), in reference to a late foetus of Oryeteropus : — " Quant aux circonvolntions, leur

analogic est complete avec celles du Tamandua." He proceeds to state that in tlie adult

the resemblance to Ilyrmecopliaya becomes more marked. In giving details to support

the latter statement, Pouehet gives a free rein to his imagination. Probably the

culminating instance of this is his statement that the fissure of Sylvius is well

marked (p. 17). There is not the faintest trace even of a, fossa Sylcil.

Gervais also insists in equally decided terms upon the close resemblance between the

hrain, and especially the cerebral cortex, in Myrmecophaga and Oryeteropus t. He

concludes his remarks upon this suhject with the following words :—" Je lui [I'Orycterope]

trouveune analogic incontestable aveccelui du grand Fourmilier, c'est a dire duTamanoir.

L'un et I'autre ont daus leur forme quelque chose du cerveau des Carnivores, mais avec

moins de circonvolutions, et le type en ]-este distinct a certains egards." And For])es

adds his testimony to this fancied resemblance, wdiich Pouehet and Gervais had pre-

viously described, in the following tei-ms : — ''Oryeteropus in its cerebral characters seems

to approach Myrmecophaya more nearly than any other form, the sulci and gyri of the

brains of the tw^o forms, as well as tlieir conformation, being very similar " %.

In two animals which follow similar modes of life and whose dimensions are not

widely different, it would be strange if there were not some points of resemblance, but

there is not so much justification for pointing resemblances in the pallium of Oryeteropus

and of Myrmecophaya as there would be in a comparisan of Ocls with Canis. It is

perhaps only just to the authors of the remarkable statements quoted al)ove to

mentioned that there is no evidence to show that any of them ever saw the brain of an

adult Oryeteropus.

In spite of a somewhat illusory resemblance in general shape, which iiaturally obtrudes

itself in the examination of cranial casts, the configuration of the actual brain of

Myrmecophaga presents a decided contrast to that of Oryeteropus. To begin with, the

shape of the pallium is very different in the two forms. For in Oryeteropus the ventral

boundary of the pallium, Avhich of course is formed by the rhinal fissure, is horizontal ;

and hence there is no caudal downgrowth of pallium such as we find in the brain of the

Ant-eater. There is no trace of a fossa Sylvii in Oryeteropus, for the pallial area immedi-

ately above the mid-region of the rhinal fissure is quite smooth.

In my specimen of Oryeteropus a sulcus, the arrangement of which is analogous to

that of the supraorbital or presylc'uni sulcus of the Dog and to the sulcus 3 in Myrme-

cophaga, springs from the mid-point of the anterior rhinal fissure, and extends obliquely

forward and upward to wnthin a distance of about 5 mm. from the interhemispheral

cleft. In the two brains of Oryeteropus in the College of Surgeons, this sulcus springs

from the cephalic extension of the posterior rliiual fissure, which is independent of the

anterior rhinal fissure.

* G. Pouc-befr, 0^). clt. torn. vi. p. 15. t P. Gervais, op. cti. pp. 47 & 48.

X W. A. Forbes, op. cit. p. 295.

47*

341' DR. »• ELLIOT SMITH ON

From about the micl-poiut of the sulcus |S another sulcus takes origin, and after arching

mesially and caudally, extends directly backward as far as the posterior extremity of

the hemisphere. This sulcus is exactly analogous to the sac/lttal sulcus (y). In parts

this sulcus is very shallow and sometimes interrupted. In my specimen the sulcus is

more complete upon the left than upon the right hemisphere.

The relations of the sulci /3 and y the one to the other are constant in the three

brains to which I had access. This arrangement differs but slightly from that obtaining

in Myrmecophaga, and which is generally prevalent among the quadrupedal Mammalia

having convoluted brains. The appearance of the combined sagittal and supra-

orbital sulci and the relation of the latter to the rhinal fissure present even greater

resemldance to the arrangement prevalent in the Ungulate brain than that of the

Carnivore.

Midway between the sagittal sulcus and the rhinal fissure we find a series of frag-

mentary sulci whose extent is variable in different brains. The horizontal sulcus of Avhich

they constitute the rudiment is the homologue of that which Krueg calls the fissura

su-prasylvia in the Ungulata *. This sulcus is the homologue of the suprasylvian

sulcus of the Carnivora, and of the rudimentary representative (S) of this in

My rmecop h aga .

In many Ungulata the "fissura suprasylvia " is horizontal, just as it is in Orycteropus,

but in others the more definite formation of a Sylvian fissure becomes associated with an

arcuate arrangement of the suprasyMan sulcus. In the Carnivora and Myrmecophagidce

the representatives of the suprasylvian sulcus always present a deep ventral concavity.

At the same time we must not lose sight of the fact that in many Ungulata the supra-

sylvian sulcus is decidedly arcuate. But we associate this arcuate condition of the

sulcus in question with a relatively much higher degree of pallial development than is

necessary to give rise to an arcuate condition in the Carnivora. In other words, an

arcuate suprasylvian sulcus is a characteristic feature of the Carnivore's brain, whereas in

that of the Ungulate it is an indication of a high state of pallial development.

The fact that Ovycteropus jiossesses supraorbital (jS) and sagittal (y) sulci, which are

analogous to those I have already described in Myrmecophaga^ is not to be considered

as an indication of a close kinship, but merely signifies that both of these peculiar

animals belong to the great group of mammals which also includes all the Ungulate and

Unguiculate animals, as well as, in all probability, the Rodentia and Chiroptei-a.

The fact that Orycteropus possesses a horizontal rhinal fissure, and consequently

exhil)its no tendency towards the formation of a pallial downgi'owth at the posterior part

of the hemisphere, distinguishes this peculiar mammal from the Ant-eaters and Unguicu-

lata, and suggests a rajjprochement with the Ungulata.

But, it may be argued, the absence of a fossa Sylvii in Orycteropus clearly distinguishes

it from the Ungulata, in which a Sylvian fissure (in the same sense in Avhich this term

is used in speaking of the Carnivora) is well developed. But there are distinctions

between the Sylvian fissure of the Carnivore and the Ungulate. In the Ungulata it is

* Julius Krueg, op. cit., Zeitsch. f. wissensch. Zool. Bd. xxxi.

THE BEAIN IN THE EDEXTATA. 345

ixmisnal to find the fossa Sylvii, or tlie fissui e wliicli is formed l)y the meeting of its lips,

so well defined in the neiohbourhood of the rliinal tissui-e as is customary in the Cariii-

vora. Sometimes, it is true, the posterior lip is as well defined as it is in Caruivora, as,

for instance, in the brain of the Pig (S/is) ; but very often the posterior lip, which we

have already noted as the most important boundary of the fossa Sylvii, is not so well

formed, and in mnny Ungulates tlie Sylvian fossa becomes reduced to insignificant

proportions. In some Ungulates it becomes so far reduced as to be a mere horizontal

depression ab:ve the caudal extremity of the anterior rhinal fissure, with no attempt at

the formation of a fissure. The most extreme instance of this reduction with which I

am acquainted is the Musk-Deer (Moschus moscJiiferns), excellent figures of which have

been provided for us l)y Tlower *.

In this animal we find a brain of peculiar simplicity, which presents a remarkalde

resemblance to that of Orycteropus. If we compare Plovver's fig. 12 with the repre-

sentations of the lateral aspect of the hemisphere of Orycteropus (figs. 2 and especially 5),

this similarity will be at once apparent. In the two brains of Orycteropus in the

College of Surgeons we have already observed that the anterior is distinct from

the posterior rhinal fissure, and that the latter extends forward for some distance

above and parallel to the former. This arrangement becomes more intelligible when we

compare it with the condition in Moschus. In this interesting brain the posterior

rhinal fissure also appears to extend forvvavd above and parallel to the anterior rliinal

for a considerable distance. But the anterior rhinal fissure joins the posterior rhinal,

before the apparent anterior extension of the latter overlaps the former ; and in

addition the area between the two overlapping fissures is depressed, so tliat by com-

parison with Myrmecopliaya or any of the common Carnivores or Ungulates we find

in this depression the representative of the fossa Sylvii. In Orycteropus it is probable

that the apparent cephalic extension of the posterior rhinal fissure is intrapallial and

represents the upper boundary of the fossa Sylvii, the relation of which to tiic sulcus

j3 is identical with that which obtains in Ilyrmecophaga (tig. 7)-

The configuration of the pallium in Orycteropus is analogous to that which is found in

the simplest form of Ungulate brain. The pallium in Orycteropus is relatively much

smaller than it is in Ilyrinecophaga, and this fact probably explains the great difference

in the size of the corpus caliosum in the two brains. It is also much smaller than

the pallium in any Ungulate with which I am acquainted.

Tiedemann, Pouchet, and Turner, in the memoirs to which I have frequently

referred, have given figures and brief descrii^tions of the brain of the Two-toed Slotb,

and in Gervais's excellent figure of the cranial cast of Cholcepus the shape and size

of a brain of this genus are accurately represented. Leuret andPouchet have figured

the brain of the Three-toed Sloth, and Gervais has represented a cranial cast of this

genus.

"While these contributions to our knowledge relieve me from the necessity of describing

* W. H. Flower, ' Oii the Structure and Affinities of tlie 3Iisk-Deer,' Pi-oc. ZojI. Sao. London, March, 1875.

31.6 DR. G. ELLIOT SMITH ON

tlie shape and size of the brain in this family, they unfortunately convey a very imperfect

idea of the exact couJignration of the pallium of Chola'ims awdi Bradypas. This is all

the more unfortunate because the state of preservation of my specimens does not permit

me to describe the pallium with that amount of detail which is desirable. My observa-

tions liave been made mainly upon two representatives of each of tlie genera Bradyjms

and Cholcepus.

In all the representatives of both genera to Avhich I "have had access, as well as nil

those to which reference is made in the memoirs quoted by me, there is a very well-

defined supraorl)ital sulcus (/3) presenting peculiar yet constant features.

In Bradjipus iridaciylus the supraorbital sulcus (/3) appears to spring from the

anterior rhinal fissure near its middle, and proceed almost horizontally forward. At

its apparent origin from the rhinal fissure this sulcus is very shallou-, and may even

fail (fig. 11), but it rapidly deepens as it extends forward. It proceeds transversely

inward across the anterior pole of the hemisphere (fig. t^O), and deeply notches the

mesial surface of the hemisphere at its anterior border ( fig. 17 /3).

Fiff. 20.

Dor.sal surface of brain of Byai/i/pus triclacli/liif:. licduced to fy nat. size.

In Cholcepus didactyhis, and apjoareutly also in Cholcppus Hoffmanni (judging from

Turner's figures), this sulcus presents a disposition exactly analogous to that I have

described in Bradypus (tigs. 12 & IS /3).

In Bradydiis the sagittal sulcus (-y) is variable. In the specimen I have represented

(fig. 20) there is an extensive sagittal sulcus which is almost two thirds of the length

of the hemisphere. It crosses the posterior border to become continuous with the

sulcus a on the mesial surface. On the dorsal aspect of the anterior pole of the

hemisphere there is another sulcus which probably belongs to the same (7) series. It

begins just behind the sulcus /3, and extends backward for a short distance laterally to

the main part of the sulcus y. The representatives of the y series of sulci present a

slightly different arrangement on the smaller brain of Bradypus. On the left hemi-

sphere the fissure 7 is divided into two parts, just as we have noted in the first brain.

Of these the posterior, which is in continuity with the sulcus a', extends forward for

only about half the length of the hemisphere. The anterior fragment of the sulcus

THE BRAIN IN THE EDENTATA. 317

begins on the mesial side of the posterior fragment and extends forward towards the

sidcus /3, bitt just liefore its termination it gives off a peculiar hook-like lateral branch.

On the riglit hemisphere the sulcus y is split up into three parts, of which the anterior

and posterior are very short and laterally placed. The intermediate segment, which

occupies about tlie middle two fourths of the hemisphere, overlaps both of the other

fragments on their mesial side.

In the admiral)le representation of the dorsal aspect of a cranial cast of Brndypm

which Gervais gives, the sagittal sulcus is represented by a single and very definite

furrow which extends almost the whole length of the hemisphere. After comparing the

condition of tlie 7 series of furrows in Bradypus with the analogous sulci in Cholcppus,

it seems possible that the fragmentary sulci which we have found in the former may

represent the two sagittal sulci which we find in the Two-toed Sloth.

In one of my specimens of Chola'pns didaclylm a sulcus begins near the lateral margin

of the posterior surface, and after pursuing a mesial course along the superior border

of the hemisphere it bends forward, at a distance of 7 mm. from the mesial plane, and

extends the whole length of the hemisphere till it meets the sulcus /3. At a distance

of 9 mm. from its cephalic limit this sulcus takes a sharp bend toward the mesial

plane and continues its course at a distance of about 4- mm. from the great inter-

hemispheral cleft. Erom the caudal extremity of the more raesially placed part of the

sulcus a much shallower sagittal sulcus arises and proceeds backward almost to the

posterior border of the hemisphere, dividing the area between the sagittal sulcus (y) and

the interhemispheral cltft into two equal areas. This condition is practically symmetrical

in the two liemispheres.

In the second brain there were also two sagittal sulci, but tliey were apparently not

so complete (fig. 12) as those just described.

In a figure which Pouchet gives of the dorsal aspect of the brain of a young

Two-toed Sloth two very complete and independent sagittal sulci are represented, of

which the lateral unquestionably represents the sulcus siKjiltalis of other forms. Again,

in the cranial cast of Cholcepiis which Gervais figures there are two very distinct sulci.

In the brain of Choloepits Hnffmanni which Turner has figured, we find fragmentary,

sulci representing these two sulci. The proper sagittal sulcus crosses the posterior

margin of the hemisphere and bends to the lateral side of the mesial or subsidiary

sagittal sulcus, where it suddenly ceases. Further forward we find traces of the anterior

portion of this sulcus.

The question as to the na' ure of the mesial sagittal sulcus naturally suggests itself.

It seemed at first not unlikely that this sulcus might represent the anterior part («") of

the splenial sulcus, taking into consideration the course of the a' element of the sjilenial

sulcus and the fact that it is not uncommon for this sulcus to extend on to the dorsal

aspect of the pallium in many Ungulates and other mammals. But the existence of a

very deep sulcus on the mesial surface in the usual position of a", and the extreme

shallowness of the mesial sagittal sulcus, lead me to discard this suggestion and to regard

the additional furrow as a mere mechanical product of the peculiar pallial growth of

Choloepus.

348 DR- G. ELLIOT SMITH ON

When we consider the close resemblance in shape between the brains of the Sloths and

the gigantic extinct Ground-Sloths, and in view of the fact that increase in bodily

dimensions in any group of mammals usually implies a more extensive pallium, we

mio'ht expect to fiiid in the brains of Megatherium, Mylodon, and Scelidothermm some

signs of a richer pattern of sulci and perhaps a definite medial sagittal sulcus. So far as

can be judged from the figures which Gervais gives of the cranial casts of these extinct

monsters, the brain of Mylodon appears to have been richly convoluted after the analogy

of the brain of the rhinoceros. While we can readily recognize the sagittal sulcus, we

cannot be sure of the presence of a definite mesial sagittal sulcus after the manner

of Cholaepus. In Scelidotherinm, whose brain is just like a very much enlarged brain of

Bradypus, there is a typical sagittal sulcus, but we can recognize no mesial sulcus.

The same remarks might ajiply to the brain of Megatlierium ; but the observer cannot

fail to be struck with the apparent simplicity of these two brains. In the brains of such

large animals, when we consider the well-developed sulcal pattern in the minute

Bradyjnis, we might have expected an extremely rich and complex pattern of sulci.

There appears to be some indication of this in the cranial cast of Mylodon.

On the lateral aspect of the sagittal sulcus there is, in the brain of BiHidypus, a strongly-

arched sulcus whose features are very constant in all the brains which I have examined,

and of "nbich there are records as well in the cranial casts. It is unquestionably the

liomologue of the suprasylvian sulcus of tlie Carnivores, to which we have referred as S

in the other Edentate brains. It is interesting to note that it is strongly arcuate, like the

corresponding sulcus in the Carnivores and its rudiments in the Ant-eaters ; for it

therefore contrasts in a marked manner with the corresponding sulcus in the lowlier

Unffulates and the Aard-vark, in which it is horizontal.

In both of the brains of Bradypus which I have examined, a deep furrow springs

from the angle of junction of the anterior and posterior rkinal fissures and extends

obliquely upAvard, with a slight inclination backward toward the central point of the

concavity of the sulcus S. This furrow we may for the present distinguish as the sulcus

/I. If we were considering the brain of a Carnivore or an Ungulate, there should be no

hesitation in calling the sulcus n the fissure of Sylvius (as that term is generally applied

outside the Primates), but there are reasons for some hesitancy in adopting this title

in Bradypus, because no other Edentate whatever has a Sylvian fissure.

There is a considerable resemblance between the brains of Bradypus tridactylns and

the small Carnivore Genetta t'lgr'ma, of which Mivart has given some useful illustrations *.

The cranial aspect of the pallium of Genetta, the brain of which is not unlike that of

Bradypms in shape, is impressed by sasittal, suprasylvian, and supraorbital sulci, which

in simplicity are comparable with those of the Three-toed Sloth. The shape and

appearance of the suprasylvian sulcus and its relation to the simple oblique Sylvian

fissiire are exactly comparable to the arcuate sulcus S and its relation to the enigmatical

sukais n in Bradyprns. A comparison of my fig. 11 with Mivart's fig. 11 demonstrates

this, but the similarity of our younger brain is much more surprising. The resemblance

* St. George Mivart " On the JElnrmdin" Proc. Zool. Soc. London, 1882, p. 516.

THE BRAIN IN THE EDENTATA. 319

between these two brains is rendered all the more patent from the fact that the

crucial sulcus has almost disappeared from the brain of Genetta. In makin<j^ this

comparison with the Carnivora, it is interesting to note that in its developmental

history the pallium of Bradypus (judging from the data Poucbet has provided) closely

agrees wdth such carnivores as Fells. Krueg has shown that the arcuate suprasylvian

sulcns (S) makes its a2:)23earance very early in the Cat, and the illustrations of foetal

brains which Pouchet gives clearly show that the sulcus S is a deep and well-defined

i'urrow before any other furrow makes its appearance on the cranial aspect of the

pallium. The later appearance of the sagittal (y) and supraorbital (/3) sulci also agrees

in the two forms, and there is nothing (so far as I kaou) in the developmental history

to prevent the adoption of the view that the sulcus « of Bradypus is the homologue of the

Sylvian fissure of tiie iEluroidea.

The sulcus S, which corresponds to the suprasylvian sulcus in brains possessing a

Sylvian fissure, presents some interesting points of difference in the two genera of Sloths.

We have already noted the constancy of this sulcus in Bradypus. It appears to be

equally constant in Cholappm, for all specimens — the two I have examined, those which

Pouchet and Turner represent, as well as the cranial casts — exhibit features which are in

agreement, while they all differ somewhat from the equally constant Bradypus type.

In Cholcepus the sulcus S begins anteriorly (fig. 12) either from or in close proximity

to the anterior rliinal fissure, a short distance behind the sidcus /3. It then arches

upward, then backward parallel to the sulcus y, and finally bends do\Au\vard on the

posterior aspect of the hemisphere to terminate in the neighbourhood of the end oC the

rhinal fissure. In this manner an extensive arc is formed, wliieh is also well shown in

Pouchet's young Cholcepus didaotylus and Turner's Cholcepus Kojfmamii.

The most puzzling feature of the brain of Cholcxpus is the absence of the sulcus ^i. In

none of the series of brains to wdiich I have had access is there any evidence of tlie

jjresence of this sulcus. This absence is the principal reason for hesitancy in proclnimin"-

the sulcus yi in Bradypus the homologue of the fissure of Sylvius in the Cai-nivore. For

if this sulcus is the fissure of Sylvius in the Three-toed Sloth, it is very strange that sucli

an important feature should vanish in the larger brain of the Two-toed Slotli, tlie

pallium of whicli is more complex. Between the arcuate sulcus S and the rhinal fissure

there is an additional horizontal or slightly arcuate sulcus which is lacking in Bradypus.

In all the gigantic Ground-Sloths there is a very deep and extensive sulcus S forming

a huge arcuate suprasylvian sulcus, after the manner of the Carniv^ora. There seems

to be in addition a well-defined Sylvian fissure, or rather sulcus ih. There is therefore

in all the Sloths a striking analogy in the configuration of tlieir pallium to tliat of

the smaller Carnivores.

In the smaller and more highly macrosmatic brains of the Armadillos w^e find a

much simpler pallium than among the other families. The series of variations in general

form and actual size which characterize the brain in the Dasypodidce are admirably shown

by the figures which Gervais has given of Cldamydophorus, Tatusia, Tolypeutes,Xenurus,

Basypus sexcinctus, Basypus villosus, and Priodon *.

* P. Gervais, op. (it. pi. ii. figs. 0, 7, 8, 9, 11, 10, and 12 respectively.

SECOND SERIES. — ZOOLOGY, VOL. VII. i8

350 DK. G. ELLIOT SMITH ON

In this family we find almost a complete sei'ies of intermediate forms between the

small brain of Chlumydophoras, which is but 17 mm. long- and broader than it is long,

and the laro-e brain of Priodon, which is not very different in size from those of Ilijrmcco-

phaga and Oyijcteropus, and has cerebral hemispheres not unlike those of the larger

Ant-eaters in shai)e. Between the short broad type of hemisphere of CJilamydopJwrus

and the long and relatively narrow type of Priodon, we find within this family all

intermediate gradations. In Xenurus and Tatusia the short square form is not yet

lost, while in Toli/peutes and Dasijpus, especially the species sexciiictus, we fi.nd a

decidedly elongate type of hemisphere making its appearance. The transition from the

hemisphere of Dasi/p)us sexciiictus to that of Priodon is practically a question of mere

increase in size.

In spite of these great variations in external form, there are obvious signs of the

family resemblance in the configuration of the pallium. Such being the case, it is

of interest to note how much cerebral form may become modified in one homogeneous

family. This fact emphasizes the extreme caution which should be exercised in drawing

conclusions from the mere shape of the cranial cavity of fossil forms.

In the small brain of Chlami/dojihorns, which lacks even a rhinal fissure, it is not

surprising to find a complete absence of sulci in the small pallial area. The only fissure

in the hemisphere of this peculiar Armadillo is the hipj)ocampal, which is absolutely

constant in all mammals, and is never found outside the Mammalia.

I have already had occasion to call attention to a small pallial sulcus, distinguished

as /3, which is present in all the Armadillos except Cldauiydopliorus. This sulcus is

sometimes continuous with the posterior rhinal fissure, as, for instance, in Dasypus ;

at otlier times it is separate, as in Tatusia. It is not unlikely that this small sulcus is

the homologue of a n.ore extensive sujiraorbital sulcus (/3), which the ancestors of the

Dasypodidce possessed. In this case a small area immediately below the point of junction

of the sulcus in question and the posterior rhinal fissure might be regarded as the

analogue of the fossa Sylvii.

Tiie disposition of this sulcus (lig. 10), its position on the hemisphere, and its relation

to the rhinal fissure all support the analogy to the sulcus /3, which I have suggested.

In addition to the pallial sulcus /3, there is in Uakypms (fig. 11), Tatusia (fig. 13), and

sometimes in Xenurus a second pallial sulcus, which extends obliquely upward and

backward from a point just above the junction of the posterior rhinal fissure with the

sulcus /3. The presence of this sulcus in the genera Dasypus and Tatusia and its

constancy, indicate that it is a feature of some niorjdiological importance. It is not

improbable that we must look to the suprasylvian sulcus (o) of other families for the

homologue of this, which we have distinguished as o in the Armadillo. In a brain

with a reduced pallium such as that of the Dasypodidce the suj^rasylvian sulcus, which

we have already learned to regard as having considerable morjihological importance and

as appearing early in phylogeny, would probably occujjy the situation which the sulcus

g occupies in Dasypus.

It is particularly unfortunate that the only brain of the Dasypodidce Avith which we

are not acquainted is that of the Giant Ai'madillo [Priodon), because it is highly probable

THE BEaIN IX THE EDENTATA. 351

that in this large brain the pallial snlci wonld bo snfficiently ^voll developed to settle

these difficult morphological problems *.

The most noteworthy feature of the brain of the gigantic extinct Arniadillo is the

relatively diminutive proportions of the cerebral hemispheres. In Ghjptodon we find

hemisjDheres only slightly larger than those of Priodoii ; and the relatively small pallium

apjiears to be almost, if not quite, smooth. The extreme macrosmatism of the living

Armadillo is even more exaggei-ated in the extinct forms, and especially Gbjpfodou,

Avliich exhibits enormous conical olfactory bulbs attached to the hemisjiheres by means

of large peduncles.

Thanks to Max Weber, we ha^e now a more exact knowledge of the l)rain of the

Pangolin than the works of Pouchet and Gervais provide. Por in bis important monograph

upon Manis Weber gives us some excellent figures of the brain, accompanied by a brief

concise description. I have examined two brains illustrative of this genus.

As I have already pointed out, the anterior rhinal is quite distinct from the posterior

jhinal fissure. The latter becomes continuous, as we found to be the case in Dasypus,

with a pallial sulcus which extends obliquely upward and forward to\vard the anterior

pole of the hemisphere. Weber calls this the "/issnra imrsylvla,'' but says that its

homology must remain doubtful. I think that we may, without hesitation, regard it

as the homologue of the sulcus /3, Mhicli corresponds to the presylvkm (Owen) or supra-

orbital (Flower) sulcus of other mammals. In Weber's specimen this sulcus becomes

directly continuous with a well-defined and typical sagittal sulcus (y), in a similar mannei"

to the arrangement we have already noted in Orycteropxs and in some of our specimens

of Cliolpa-MS {vide Weber's figures G7 and 68). In the better-preserved of my two

specimens the supraorbital sulcus (/3) is not connected to the sagittal sulcus (7).

We may, in agreement with Max Weber, regard the area just below the junction of

the posterior rhinal fissure with the supraorbital sulcus (/3) as the fossa Sylvii ; but I must

entirely disagree with him when he describes a Sylvian fissure in addition to tl)is.

Thus he says :— " Aus der Possa Sylvii ziehen zwei weitere Purchen : die eine [/3]

nach vorn und oben, um in die spater zu nennende Pissura sagittalis einzutreten, die

andere vertikal noch oben, umweiterhin nach hinten umzubeugen. Letztere mochte ich

als Pissura Sylvii deuten, wahrend die Homologie der ersteren mir zw^eifelhaft gehliel)en

ist." t This region of the brain is unfortunately not shown clearly in Weber's figures,

because it is not easy to determine which are true sulci and which merely vascular

depressions. In the only brain of Hauls upon which I have been able to examine this

region there is a large arcuate fissure, which appears to spring from the lowermost part

of the supraorbital sulcus, and behaves in a manner exactly similar to the suprasylvian

sulcus (^) in the Sloths. The homology of this sulcus with the suprasylvian sulcus of

* In a popular work edited by Martin Diineau (Casscll's ' Xatural Histor)- : ' London) a figure, entitled

" Krain of the Armadillo," accompanies a description oi Priodon (vol. iii. p. IS:}). The brain is as richly convoluted

as that of the Sloths, but is utterly unlike that of any Armadillo I know, and is certainly not the brain of Priudon ;

for, apart from the configuration of the cerebrum and cerebellum, the olfactory bulb is relatively as small as that of

Cydotarus, while all the Armadillos have enormous bulbs.

t Max Weber, J Zool. Ergebnisse, p. 87.

48*

352 DK. G. ELLIOT SMITH ON

other mammals seems to be much more likely than with the Sylvian fissure, as Weber

suggests.

The arrangement of the sulci in this brain presents a peculiar resemblance, in respect

to ditTerent points, to the brain of the Armadillos and Sloths. On the one hand, the

general plan, the arcuate suprasylvian sulcus, the sagittal sulcus, and the supraorbital

sulcus considered together, strongly recall the brain of the Sloth. And yet we must at

the same time admit that these features arc the common inheritance of widely different

mammalian families. On the other liand, the condition of the rhinal fissure and its

relation to the supraorbital sulcus shed an interesting light upon the brain of the

Armadillo. More especially is this the case in the foetal Manis {vide Poiachet, oj). cit.

pi. V. fig. 9), in which the combined posterior rhinal fissure and sulcus j3 form an exact

facsimile of the arrangement of these sulci in Dasypus. Then, again, the relation of the

suprasylvian sulcus (S) to the sulcus /3 in Manis is identical with that of the sulcu.s which

we have called S to the sulcus /3 in Dasijpiis.

In a brief note Huntington sums up * the features of the brain in the Edentata

{Mi/rniecophaga, Tamaudim, Arctoplthecus, Dasypus, Tatnsia, and Ilanis) in the following

terms: — "In the brain (hemispheres) the uniform presence of a more or less modified

longitudinal sagittal sulcus parallel to the great longitudinal fissure, the tendency to the

formation of a transverse frontal sulcus, and the absence of a distinct Sylvian fissure, are

to be noted as Edentate characters."

Taken as it stands, this statement is very misleading. In the first place, " the presence

of a modified lon""itudiual sa<?ittal sulcus " and " the tendencv to the formation of a

transverse frontal sulcus " are no more entitled to be called " Edentate characters " than

they are to the designations " Carnivore " ov " Ungulate." Instead of being the special

and exclusive characteristic of the Edentata, these sulci are the common property of the

whole Mammalia, excluding probably the Mouotremata only.

This writer also refers to the absence of the Sylvian fissure as an " Edentate character."

In the strict application of the term it may be correct to say that the Edentata possess

no Sylvian fissure. But to baldly make this statement with no word of exj)lanation

cannot fail to give rise to serious misapprehension. Even admitting, for the sake of

argument, that the sulcus /// of Bradypus is not as much entitled to the name " Sylvian

fissure " as the topographically analogous depression in Genetta, it seems to me to be

distinctly misleading to say of Myrmecophaga that it possesses " no distinct Sylvian

fissure." Tliis may be literally true enough, but some cvplanation is surely necessary to

indicate that although the Great Ant-eater's brain possesses " no distinct Sylvian fissure,"

yet, at the same time, it differs only in degree from the brain of the Dog, in which a

typical Sylvian fissure exists.

The fuller discussion of the data relating to the pallium will be left for consideration

in the concluding remarks. At present we may pass to the consideration of the other

parts of the brain.

* G. S. Huntington, op. cit., Trans. New York Acad, of Sciences, Jan. 13, lb'J6, p. 98.

THE BRAIN IN" THE EDENTATA. 353

The Brain-stem.

By the term " In-aiu-stem " we understand that part of the brain which remains after

the removal of those morphological excrescences, the cerebral hemispheres and the

cereljelluni. It is a term which is used merely as a convenience in description, and has

no claim to morphological accuracy.

It is unnecessary to discuss in detail the featiu'cs of this part of the l)raiD, because

its morjihology is practically unchanged iu the main body of mammals, if we make

due allowance for purely functional modifications and variations in size. We shall

therefore consider this part of our subject in as brief a space as is consistent with

lucidity.

The ventral surface of the thalamic region and mesencephalon forms in Orycteropus,

in common with most other mammals, a broad exposed area (tig. 1) extending from the

optic tract in front to the prominent pons Varolii behind. The lateral part of the

subthalamic region is hidden by the anterior part of the eras cerebri, Avhich is itself

partially overlapped by the lohun pi/riformis posticus. The mesial border of the anterior

extremity of the crus cerebri is about 6 mm. from the mesial plane, but as it proceeds

backward it inclines obliquely inward, so tliat when it reaches the transverse strand of

the pons Varolii it is in close proximity to the crus cerebri of the other side.

Thus a triangular interval is lett between the anterior extremities of the crura cerebri.

A large prominent mass of pale colour occupies this interval. The posterior part of this

mass consists of two large ellipsoidal bodies, each G mm. long and 3 mm. thick, wliich

are placed so close the one to the other that it is necessary to examine them very closely

to discover the slight median groove Avhicli indicates their line of separation. They are

the corpora mumuiillar/a. The interval between these bodies and the optic chiasma is

occupied in the mesial 2)laue by the thin floor of the third ventricle — the inftDitUbaliiin —

from which the pituitary body is suspended in the normal state. In this specimen of

Orycteropus, liowever, the pituitary body has Ijeen torn otf, leaving an elliptical aperture,

which opens into the cavity of the third ventricle (compare fig. I).

Extending backward from the corpora mammillaria to the pons Varolii there is a deep

mesial cleft between the two crura cerebri.

When the crus cerebri makes its tirst ajipearance upon the base of the brain by coming

from under cover of the optic tract it consists of a strand of fibres 10 mm. broad, but as

it extends obliquely backw^ard it becomes narrower and plumper, and when it disappears

under the fibres of the pons it is only 5 mm. broad, but 2'5 mm. thick. In many of the

other Edentates (figs. 6 and 9) the crvis cerebri is a more prominent strand, and this is

doubtless a result of the relatively greater size of the pallium than is tlie case in

Orycteroi)us.

The interpeduncular cleft is occupied immediately in front of the jions Varolii by an

ellipsoidal nodule of grey substance — the corpus hiterpedunculare — iu all the Edentata

(figs. 1, 6, and 9). This body is 5 mm. long in Orycteropus, and of corresjoondingly

large dimensions in all tlie other Edentates.

Along the lateral border of the cms cerebri in Orycteropus, parts of the oj)tic thalamus

351 Dl?. G. ELLIOT SMITH ON

and the nieseuccphalon may be seen cropping out in a \ie\\ of the ventral surface of the

hraiu. In the angle between the lateral part of the pons Varolii and the crus cerebri we

find a triangular area which we may call the area tegmenti, because it is the surface of

the iegmerdum, i. e. the essential part of the basal region of the mesencephalon. In

Man the corresponding region is called the area lemnisci, because an important nerve-

tract in the tegmentum known as the fillet or lemniscus appears on the surface in this

situation. In front of the area tccpnenti we find a very prominent hemispherical boss of

grey substance, the corjms genicidatum postlcum [vel mediale']. This body is partly

hidden from view by the overlapping fold of cortex (pyriform lobe). If we remove this

cortical operculum we shall be able to see the optic tract extending obliquely backward

and outward across the crus cerebri, and then expanding to cover a small ill-defined boss

of grey substance Avliich is placed just in front of the posterior geniculate body. This is

the corpus cjeniculatum. anticum [vel lalcrale]. Id a view of the base of the brain with

the cerebral cortex undisturbed, the anterior geniculate body and the lateral part of the

optic tract are hidden from view.

Pis. 27.

colum. fornicis

.cortex

Corp. striat.

gang], habenul.

thalam. opt.

— -hippocamp.

-Corp. pineale

'corp. geniculat. post.

r--corp. quadrigem.

vel. meduUare

--nerv. V.

ped. cerebel. sup.

'" colum. cerebel.

^-nerv.Vin.

"tuber, acust. lat.

~'- tuber, acust. med.

"•-ventr. IV.

Dissection to expose dorsal .surface of brain-stem in Ori/cterojiKs. Enlarged .| diam.

In a profile view of this region (fig. 2) we can better appreciate the large dimensions

of the prominent posterior geniculate body, which seems to rest on the crus cerebri, and

by contrast Ave can see how ill-defined are the boundaries of the anterior geniculate body ,

which appears as a slight swelling that can only with difficulty be distinguished from

the optic tract in front and the optic thalamus on the dorsal side. Above and behind the

posterior geniculate body we see the corpora geniculata in profile. But these bodies can

be more satisfactorily studied in a dorsal view (fig. 27).

The dorsal siu-faces of the optic thalami and the anterior pair of the corpora quadri-

THE BKAIN IX THE EDENTATA. 355

gemina form a large flattened area of a quadrilateral shape. The optic thalami are

separated tlie one from tlie other by a median slit, which is the third ventricle. A

shallow furrow begins on each side near the posterior extremity of the third ventricle

and proceeds obliquely outward and backward at an angle of about 60° with the mesial

plane ; this furrow on each side serves as a line of demarcation between the optic thalamus,

which is placed in front of it, and the corpora quadrigemina behind it. Tlie anterior

pair of the corpora quadrigemina form two broad flattened eminences (fig. 27) which

rise to a slightly higher level than the optic thalami and posterior corpora quadrigemina.

Together they form a sector of about 120 of a circle of 95 mm. radius. In the mesial

line they are separated by a shallow furrow. A small body shaped like an arrow-head

lies free in tlie anterior part of this mesial furrow. This is the pineal body. It is solid, Ijut

is attached anteriorly to the thin walls of a pouch-like diverticulum of the third ventricle.

A very deep furrow extends across the mesial line under the corpus pineale (fig. 4<), and

from this the furrows which separate the corpora quadrigemina from the optic tlialanius

start. If these furrows be traced laterally they will be found to dip down upon the

lateral surface of the brain-stem (fig. 27), and in the deep groove thus formed we find

the large projecting posterior geniculate body (Hgs. 27 and 2).

The dorsal surface of the oiitic thalamixs presents a quadrilateral outline. Its anterior

and posterior boundaries are two parallel obliquely-placed grooves, both of which begin

at the mesial plane and extend outward and backward, the anterior boundary for aljout

16 mm., and the posterior boundary (which is the thalamo-mesencephalic groove) for

9'5 mm. The postero-lateral extremity of the optic thalamus consists of a large rounded

knob, the outline of which resembles, both in extent and degree of curvature, the postero-

lateral boundary of the quadrigeminal body. Trom a profile view (fig. 2) we can readily

understand hoAV this large lateral knob of the optic tlialamus is related to the ill-defined

anterior geniculate body and the optic tract. The oblique antero-lateral boundary of the

optic thalamus consists of a deep groove Avhich separates it from the corpus striatum

(tig. 27). Upon each side of the posterior part of the third ventricle, and just in front of

tlie attachment of the pineal diverticiilum, we find a large pear-shaped area very faintly

marked off from the rest of the dorsal surface of the optic thalamus by shallow furrows.

This is the ganc/Uon habciiakc. It extends about as far forward as the mid-point of the

slit-like third ventricle and then gradually shades away. A very prominent ridge of

nerve-fibres is connected with this ganglion, and forms the dorso-mesial lip of the third

ventricle in the Avliole of its extent : this is tlie tcenia tliaJami.

The 2)osterior quadrigeminal bodies form a pair of large rounded projections upon the

postero-lateral aspects of the anterior quadrigeminal bodies. They are placed a con

siderable distance apart, and are connected across the middle line by a tempering narrow

bridge of grey substance (fig. 27). Upon the lateral aspect of the mesencephalon each

posterior quadrigeminal body is prolonged into an oblique column of a greyish colour

which extends downward and forward toward the prominent, somewhat triangular,

posterior geniculate body (fig. 2). This column is called the hruchiaub of the posterior

geniculate body. In the angle between it and the crus cerebri we find the irregularly

quadrilateral region of the urea tecjmenti.

356 DK. G. ELLIOT SMITH ON

In a mesial sagittal section of the brain the ventricles are opened up, but ^s their

features agree with those of the Eodentia, Carnivora, TJngulatn, and the main body of

Mammals, we merely need review them very briefly.

The third ventricle is a vertical slit-like cavity between the optic thalami. These

bodies, however, meet in the mesial plane and fuse so as to form a large elliptical bridge

of grey substance — the commissura mollis— wh.\c\\ therefore causes tlie disappearance of

a large part of tlie third ventricle. In fact tlie third ventricle becomes reduced to a

narrow channel which surrounds the soft commissure (figs. 4. 17, and 18). The roof of

this ventricle is formed by a thin epithelial layer which extends from the upper part of

the psalterivm ventrale to the upper part of the pineal body. At the situation of its

attachment to the pineal body a little transverse strand of nerve-fibres is found crossing

the middle Hue in the roof of the pineal recess. This consists of fibres proceeding from

the gaiiglioH Jiahenulcr and tcenia thalami of each side to the ganglion Jiabenulce. of the

other side, and is hence known as the coinriiissura habenularum.. It is sometimes called

the commissura superior, but Ziehen has recently caused some confusion by calling the

dorsal commissure in Monotremes and Marsupials by this name*.

Between the roof of the third ventricle and the posterior superior part of the soft

commissure the ganglion habenulae may lie seen in the lateral wall of the ventricle as a

peai'-shaped projection (figs. 1, 17, and IS). The anterior wall of the third ventricle is

formed by the lamina terminalis, which extends from the epithelial roof above to the

optic chiasma below, and contains the psalterium ventrale and the anterior commissure.

Between the soft commissure and the intercommissural copula (/. e. the part of the

lamina tei*minalis [fig. 23, l.t'.'] which links the anterior commissure to the psalterium)

a small elliptical aperture will be found in the lateral wall of the ventricle. This is the

foramen of Monro, leading into the lateral ventricle. The floor of the ventricle is formed

by a thin lamina extending from the optic chiasma to the corpora mammMlaria. This

floor is drawn downward into a funnel-shape— the ivfimdibuJiim — and to its apex the

pituitary body is attached (figs. 4 and 18).

The posterior walls of the third ventricle are formed by a very solid mass composed of

the anterior end of the mesencephalic tegmentum and the corpora iimmmillaria. The

anterior surface of this mass presents a regular curve which leads back to the floor of

a narrow channel opening out of the third ventricle. This is tlie aqueduct of Sylvius.

The roof of the anterior aperture of this channel is formed by a large mass of nerve-

fibres presenting a sickle-shape in section. This is the posterior commissure. This broad

funnel-shaped anterior opening rapidly contracts to a narrow canal, which extends back-

ward, with a slight obliquity upward, and tunnels the mesencephalon between the anterior

quadrigemiral bodies and the tegmentum, which forms its floor. As the aqueduct

approaches the posterior extremity of the anterior quadrigeminal bodies it gradually

expands not only in vertical extent, but even more markedly in the lateral direction, so

that an elongated funnel is produced, the wide mouth of which looks in the caudal

* Ziehen, op cit.

THE BRAIN IN THE EDENTATA. 357

direction. This mouth is closed by a very thin vertical film — the a.nterior medullary

velum — which proceeds upward to be attached to the upturned edge of the narrow bridge

of grey substance which connects the two posterior quadrigeminal bodies

Upon being traced downward this medullary velum (called by the older anatomists

the valve of Vieussens) descends until it reaches the tegmentum, upon which it rests,

without, however, becoming attached to it. It proceeds backward, forming the anterior

part of the roof of the flattened fourth ventricle, and becomes attached to the ventral

surface of the cerebellum (figs. 4, 17, and 18).

The aqueduct of Sylvius presents similar features in all the Ilynmcophayida;, and in

Cholcepus, Manis, and in the majority of mammals included in the Carnivora, Ungulata,

Rodentia, Marsupialia, and allied Orders.

In my specimen of Bradypus the wide anterior mouth of the aqueduct gradually

tapers as it proceeds backward, so that there is no tubular anterior constriction. Thus

the Sylvian aqueduct appears i-elatively larger than it does in other Edentates (fig. 17).

In the Brddypodldce the posterior part of the roof of the mesencephalon becomes very

much elevated, for reasons which we shall consider immediately. As a result of this the

posterior infundibular expansion becomes greatly exaggerated. The aqueduct of Sylvius

opens out of the third ventricle by a fairly wide opening and rapidly expands, so that the

posterior opening becomes very wide and the direction of the canal very oblique. These

modifications become most pronounced in Chlamydophorm, although they are already

very well-marked in Basypus.

In Mynnecoplwga and Tamandua the anterior corpora quadrigemina become relatively

smaller and flatter in comparison to the optic thalamus than is the case in Orycteropiis,

and the posterior quadrigeminal bodies, instead of being lower than the anterior,

now rise to a considerably higher level than any other part of the mesencephalon or

thalamencepbalon. In Tamandua, in addition to this, these elevated posterior quadri-

treminal bodies now become somewhat flattened betw'een the cerebellum and the cerebral

hemispheres. In the Bradypjodkla; the anterior quadrigeminal bodies become still

further reduced, but the posterior geniculate bodies, which in the Ant-eaters and the

Aard-vark are already very large, now attain enormous proportions. Compared with the

size of the corpora quadrigemina the optic thalamus is proportionately larger than it is

in the 3Iyrmecop]uigid(F and Orycteropus. I have unfortunately been unable to examine

these parts of the brain of Ilanis. But in the BasypodidcB we again find modifications

of this region. The anterior quadrigeminal bodies become even further reduced in size

than they are in the Sloths, but in addition the optic thalamus is extremely small. In

marked contrast we find a large and prominent pair of j)Osterior quadrigeminal bodies

which project upward as an elevated ridge between the cerebellum and the cerebral

hemispheres. The posterior geniculate bodies attain such large proportions that in a

profile view they would appear to be almost half the size of the optic thalamus (fig. 28).

In Chlamydophorm these changes become much more pronounced. The anterior

quadrigeminal bodies become extremely reduced and the region of the cori^ora

quadrigemina converted into a transverse vertical plate which is interposed between

SECOND SERIES. — ZOOLOGY, VOL. VII. 49

358 DR. G. ELLIOT SMITH ON

the cerebellum and the cerebral liemisjiberes. The posterior geniculate bodies still

retain their relativelyjlarge dimensions.

Fig. 28.

corp. qtraangem. post.

• Corp. quadrigem. ant.

thalam. opt.

Corp. genicnlat. ant.

j i icorp. gemoulat. post.

paraflocc. • crus cerebri

t

pons Varol.

Riglit lateral aspect of brain-stem, and cerebellum of Dasypus vUlosus. Nat. size.

In spite of all these variations in form and the relative proportions of different j)arts, the

mesencephalic region in all the Edentates conforms to the same type, which is pi-actically

constant in the Marsupialia, Insectivora, Rodentia, Ohiroptera, Ungulata, and Carnivora.

All the changes which take place are probably the direct expression of functional

adaptation to different modes of life. In animals which lead a life such as all the

Edentates follow, the sense of sight is of considerably less importance than the sense of

hearing and the all-important sense of smell. Eor most of the animals of tliis group are

nocturnal, and many of them are burrowing animals. They seek their food and pursue

the other objects which constitute the sum of their life's exertions at a time or in a manner

in which visual sensations must be of subsidiary importance. Even to the dog and cat,

who seek their visible prey with the directing aid of a highly-developed visual area of

the pallium, the sense of sight is quite subsidiary to that of smell and possibly also of

liearing. It is only natural, therefore, to expect in the Edentata, which are not so well

provided with a pallia! visual mechanism and which pursue tlieir ends under circum-

stances in which sight can avail them nothing, that the visual sense should be of even

more subsidiary importance. We have already seen that the olfactory parts of the brain

reach a very great development in this group. The auditory regions of the brain

;i.re also exceptionally well-developed, as we shall see later ; 1)ut it is quite possible

that the enormous size of the posterior geniculate body and the large dimensions of

the posterior quadrigeminal bodies may also be witnesses to the high importance of the

auditory sense.

The waning importance of the visual sense is markedly reflected in the anatomy of the

mesencephalon. The anterior quadrigeminal bodies, Avhich arc so well-developed in

Orycterojms and almost equally so in the 3Iyrmecopliagidce, itndergo a conspicuous

reduction in the DasypocUclce, and in Chlamydophorus, in which the visual activity has

become so slight as to have earned for it the name " Pichi-ciego " or " Blind Armadillo."

AVhile the anterior quadrigeminal bodies are undergoing this retrogression, the j)osterior

bodies remain, because their chief function is certainly not visual, and hence we get that

peculiar transverse ridge-like condition of the mesencephalon in the Armadillos.

THE BRAIN IN THE EDENTATA. 359

I have already had occasion to refer to the pons Varolii in Orycteropus. It is a

prominent transvei-se strand (fig. 1) of nerve-fibres which crosses the ventral surface of

the brain-stem, and, after bending up on the lateral aspect of the brain-stem on each side,

dips into the cerebellum, forming its middle pedu.ncle. In the mesial plane the pons Varolii

is 10 mm. broad and 3 mm. thick. It expands slightly on each side of the mesial plane,

and then contracts again so that at a distance of 10 mm. from the mesial plane it is

merely 6 mm. broad. At this point it splits into two strands to enclose the large fifth

nerve, the great majority of the fibres passing in front of the nerve. At the lateral

margin of the nerve the fibres collect again to form a rounded cord, the middle peduncle

of the cerebellum, which bends round the lateral aspect of the brain-stem, and after a

course of 13 mm. in the dorsal direction disappears in the cerebellum.

In Tamandua (fig. 9), Myrmecophaga, and the Bradi/podidce, the pons presents similar

features, but is relatively larger than it is in Orycteropus. In Manis and the Brady-

podidic its features are similar. In Chlamydophorus the pons is a very insignificant

bundle of fibres.

On the ventral surface of the medulla oblongata a very prominent band of fibres makes

its appearance in Tamandua (fig. 9), by coming from under cover of the pons Varolii on

each side of the mesial plane. These are the pyramidal tracts or anterior pyramids.

They are equally weU-developed in 2Iyr}nccopltag(i, and only slightly less prominent in

the Sloths and Armadillos. But in Orcteropus (fig. 1) the pyramidal tracts are flattened

bands, the position of which is indicated by the emergence of the roots of the hypo-

glossal nerve along their lateral borders. The contrast between these insignificant bands

and the prominent cords in the Ant-eaters is probably explained by the larger pallium in

the latter, because the fibres of the pyramids are derived from it.

Just behind the pons a transverse band of nerve-fibres, the corpus trapezoldemn,

emerges from under cover of the pyramid on each side and pursues a course to the lateral

border of the brain-stem. Just behiud the situation of the fifth nerve, another and much

smaller nerve — the seventh or facial — separates this trapezium (or trapezoid) bodv from

the pons Varolii. Upon tracing the trapezium a little beyond the seventh nerve it

leads to another nerve or pair of nerves, each of which is larger than the seventh. This is

the auditory or eighth nerve, composed of two parts, cochlear and vestibular respectivelv.

These nerves immediately dip into a large mass of grey substance, which we may dis-

tinguish as the tulierculum ac/istlc/im laterale (fig. 27). This lateral acoustic tubercle is

an elongated band of grey substance, of a somewhat crescentic shape, which is jslaced

mainly upon the lateral aspect of the brain-stem, at the junction of the medulla oblongata

and the pons. It begins ventrally just opposite the lateral margin of the emerging fifth

nerve, and is placed in the groove behind the middle peduncle of the cerebellum: it

proceeds obliquely upward and backward, and upon reaching the dorsal aspect of the

brain-stem it extends directly inward, closely embracing the middle peduncle of the

cerebeUuni in the whole of its course. The greater part of this tubercle lies within the

fourth ventricle, since the line of attachment of the epithelial roof of this cavity crosses

over the extreme lateral margin of the acoustic tubercle.

Three large and compact bimdles of nerve-fibres enter the cerebellum on each side of

49*

360 DE. G. ELLIOT SMITH ON

the mesial plane. These are known as its j)ecluncles. The superior cerebellar peduncles

issue from the mesencephalon and proceed directly backward, at a distance of 9 mm. the

one from the other. They soon meet the middle peduncles extending dorsally from the

pons and the fibres of the inferior peduncles which ascend from the medulla oblongata and

spinal cord. Together the three peduncles of each side form a large and massive column-

like support for the cerebellum, and hence the combined mass may be called the cohimna

Ge7'ehcUi. The fourth ventricle is a broad and very shallow cleft which lies upon the

expanded dorsal surfaces of the region of the pons Varolii and the upper open part of

the medulla oblongata. Its anterior part is placed between the two parallel superior

peduncles of the cerebellum, and is roofed by the medullary velum which stretches

between these peduncles. The posterior part of the ventricle is triangular in outline,

the lateral angle of the triangle extending widely behind the columna cerebelli on each

side and forming the lateral recess. In the floor of this lateral recess we find the

crescentic tuherciilum acasticmn kderale. On the mesial side of this, we find in the

floor of the fourth ventricle a larger i-ounded and very prominent mass of grey matter,

which we may call the tuherculum acusticum mediale (fig. 27). In the writings of

different anatomists the nomenclature of this region is often responsible for much

ambiguity. The tei'm " tuberculum acusticum " is commonly applied to that body which

I have distinguished by the adjective " laterale," and the name " trlgonum' ncusticum "

to my " mesial tubercle " ; but these terms are very confusing. For the difference in the

name leads writers to regard the tubercle sometimes as part of the trigone, at other times

as a separate body, or even to confuse the trigone with the tubercle. For the sake of

clearness of description I have introduced the qualifying adjectives " laterale "• for the

tubercle which is probably cochlear, and " mediale " for that which is probably vestibulai-,

and called them both " tubercle."

In all the Edentates the features of this region are practically constant and call for no

fuller description.

The Cerebellum.

We might with almost equal justification begin the description of the cerebellum in

the Edentata at the present time with the same remarks which Pouchet emjiloyed in

introducing the same subject thirty years ago. But if Pouchet found reason in his time

to deplore the obscurity which anatomists had allowed to enshroud the comparative

anatomy of this important organ, we at the present day have infinitely more reason to

bemoan our ignorance. Por while the subject of cerebellar morphology has received

little more illumination than it had in Pouchet's day, the feverish activity which has

prevailed in all other fields of neurological investigation has thrown such a clear light

upon the anatomy of the rest of the nervous system that by contrast our ignorance of

cerebellar morphology seems to-day greater than ever.

When this investigation was begun two years ago, I fovmd it necessary to study for

myself the comparative anatomy of the cerebellum in an extensive series of vertebrates

before it was possible to intelligently appreciate the Edentate types of cerebellum, and

understand the morphological plan to which these types conform. Perhaps the greatest

THE BEAIN IN THE EDENTATA. 301

liinclrance in this study was the stumbling'-l)lock whicli human anatomists have erected

in the shape of a cerebellar anatomy which is devoid of a rational morphological basis.

The investigator of a large series of mammalian cerebella will aj^preciate at an early stage

in his labours that underlying the apparently irreconcilable differences and seemingly

divergent designs exhibited in cerebellar architecture there is, in all the Eutheria

and Metatheria, one common fundamental plan which becomes variously elaborated in

different animals. It thus become-; possible for him to compare upon a sure and sound

basis any cerebellum, ranging from the simplest bifoliate structure of Notoryctes, to the

most complexly elaborated organ in Man ; and it is possible to construct a simple plan

for descriptive purposes which will equally apply to any representative of this large series

of mammals.

Since this work has been accomplished I have become acquainted with three memoirs

dealing with this terra iiwor/nita of cerebellar anatomy which have recently appeared.

Thanks to the kindness of the author, I have recently received a brief introductory

memoir by Stroud, who has studied the development of the cerebellum in the Cat and

in Man *.

This importaiit and interesting communication insists upon the uniformity of the

fundamental plan of the cerebellum in wZr mammals, even including the Monotremata.

[The writer does not refer to the distinct specialization of the Prototherian cerebellum,

wiiich should exclude it from this generalization.]

A most important memoir dealing with the development of the cerebellum in the

Sheep and in Man appeared at about the same time as Stroud's contribution, and in many

points confirms, and in some other respects tends to refute, Strovid's results. Por this

important contribution to this much-neglected field of research we are indebted to

Walther Kuithan f.

Theodor Ziehen has recently given us a pure description (unilluminated by any

suggestions of a general or morphological nature) of the cerebellum in the Monotremata

and MarsujHalia +.

The cerebellum in Orycteropus is a large, solid, ellipsoidal mass, the major diameter of

which is transverse, and measures (in a specimen which had been for some years in

alcohol) 47 mm. ; the maximum diameter in the sagittal is 27 mm., and the maximum

height is 20 mm. This large, somewhat flattened mass completely covers and hides from

view the fourth ventricle, and it is supported on two large columns which are 11 mm.

apart : in other words, are 5-6 mm. from the mesial plane on each side. Each of these

columns is 9 mm. in diameter, and consists of the combined cerebellar peduncles of its

own side. It is obvious from the measurements that the cerebellum must project on

each side far beyond these columns of support ; but not only is this so, but its ventro-

lateral extremities are wrapped, as it were, around the lateral aspects of the peduncles so

* B. B. Stroud, " The Mammalian Cerebellum. — Part I. The Development of the Cerebellum in Man and the

Cat," Journal of Comparative Neurology, vol. v. 1895.

t Walther Kuithan, " Die Entwickelung des KJeiuhirns bei Saugetieren," Miinchener raedicinische Abhand-

lungen, vii. Reihe, 6. Heft, 1895.

X T. Ziehen, op.cit.

362 DK. G. ELLIOT SMITH ON

that the combinod jiodunciilar masses are not visible in a profile view. In the exuberance

of its growth the mesial cej)halic and mesial caudal parts of the cerebellar mass bend in

the ventral direction, and become tucked in between the two pillar-like masses formed

by the cerebellar peduncles. These cephalic and caudal cerebellar processes come into

apposition between the columnce cerehelli (as we may call the combined peduncles) and

thus produce a deep vertical transverse slit, which Ave may call the superior recess of the

fourth ventricle {recessus superior) (vide fig. 29).

Fii;. 29.

Mesial sagittal section of the cerpbclliim of Or^iclerojpus. Enlarged -^ rliam.

Anteriorly the cerebellum is in close contact Avith the posterior extremities of the

cerebral hemispheres, and this contact adapts the configuration of the anterior margin of

the cerebellum, so that a prominent rostrum is formed projecthlg forward from its

antero-superior margin in the mesial plane. This rostrum projects into the interhemi-

spheral cleft, and partly roofs over the posterior corpora quadrigemina.

Although the surface of the cerebellum is evenly rounded in Orycteropus and does

not present any of those sudden projections Avhich are found in many mammals, it

cannot he considered even or smooth. On the contrary, the sui-face of the organ will be

found on all sides to present slight gradual elevations and gentle depressions, and these

hills and vales give the organ an irregularly-corrugated appearance. The surface of the

cerebellum is everywhere marked Avith an exceedingly complicated pattern of lines,

labyrinthine in its intricacy. These lines, the arrangement of which Ave shall find to

conform to a more or less definite and orderly plan, represent the situation of the deep

fissures, Avhich cut up the whole mass of the cerebellum into a complex mass of narrow

leaf-like folds. These folds are mutually adaptive, and are so closely packed that the

whole complex oi folia forms a solid organ.

The lateral poles of the cerebellum are formed of two large bodies, each composed

of a complex mass of folia. These masses are almost completely separated from the '

rest of the cerebellum by fissures Avliich cut deeply into the organ until they reach

the medullary matter. As the area thus separated oft' on each pole from the rest of

the cerebellum includes the homologue of the flocculus of human anatomy, and is a

natural division of the organ, we may distinguish it as the lobus flocculi, and the deep

limiting fissure as i\\e fisswra floceii t i . The latter corresponds to the pm-afloccular sulcus

THE BRAIN IN THE EDENTATA. 363

of Stroud *, who has shown that it arises at an early period of development in Man and

the Cat.

The lolms fiocculi consists of two morphologically distinct parts, which, adopting

Stroud's nomenclature, we may call the Jloccnlus and paraflocculus resj)ectively. Of

these the latter is very much Iragcr than the former, which it flattens against the

cerebellar peduncles and completely hides from view. The i^arajlocculus is a large

mass of an oval outline, which forms the greater part of the lateral pole of the cere-

bellum, being adapted to the lateral aspect of the colmnna cerehelU. It is 20 mm.

long and 16 mm. broad, and is placed obliquely, and more especially upon the caudal

aspect of the pole of the cerebellum. In a view of the cerebellum from above the

paraflocculus is visible as a crescentic area fringing the lateral and postero-lateral

margins of the organ. In a caudal view of the organ the paraflocculus is seen as an

obliquely-placed tapering mass extending from the lateral pole downward and mesially.

The paraflocculus is divided by an arcuate fissure into two parts, which we may d

tinguish as the paraflocculus ventralls and the pjara flocculus dorsalis. The former is

crescentic, and consists of eight simple folia, and behind these of a bimch of three folia

on one stalk. The. paraflocculus dorsalis con^iat^ of four branches of radiating fissures,

together forming an arc above the ventral part of the paraflocculus. The flocculus

consists of a broad flattened grouj) of folia which are hidden under the posterior j)art of

the ventral paraflocculus and adapted to tlie dorsal surface of the tuherculum acustlcum

later ale.

After subtracting the two lohi flocculi, the rest of the cerebellum may be divided for

descriptive purposes into three azygos lobes, a cephalic, a caudal, and an intermediate or

central.

The cephalic lobe, which we may call the lohus anticus, is separated from the rest of

the cerebellum by a fissure which we may distinguish as thefissurapritua. This is the

deepest fissure which crosses the mesial plane of the organ ; it is the most constant

fissure in the mammalian series, and is ever jJi'esent, separating the two simple folia

which form the greater part of the simple cerebellum of Notoryctes, and in addition it is

the first of the fissures wjiich cross the middle line to make its appearance in the course

of development, as Stroud and Kuithan have independently demonstrated. It is a

fissure of the greatest morphological importance, ranking in tliis res2)ect with the

fissura flocculi only. It corresponds to the " sulcus fur calls" of Stroud, the "sulcus

primarius cerehelU " of Kuithan. In human anatomy quite subsidiary importance is

attached to this fissure under the name '' flssura prceclivalis."

In a mesial sagittal section this flssura prima may be seen cutting very deeply into the

organ from the dorsal surface, and extending almost to the recessus superior of the fourth

ventricle. In this plane it divides the organ into two approximately equal areas, the

anterior of which corresjjonds to the lohus aulieus. Regarding the dorsal surface of the

organ, this fissure may be seen to cross the middle line slightly in front of a point midway

between the cephalic and caudal limits of the organ. It extends transversely for about

* Stroud, iijt. cit. p. 9-5.

364 DR. G. ELLIOT SMITH ON

4'5 mm. on each side of the mesial plane, and then bends obliquely forward and ontward

to reach the anterior surface of the organ. In this way it cuts off a lozenge-shaped area

on the dorsal surface, which forms part of the anterior lobe. On the anterior surface the

fissure extends obliquely downward and \^'ith a slight lateral inclination, and ultimately

reaches the situation where the middle peduncle dips into the cerebellum.

By means of this deep cleft a lozenge-shaped area on the dorsal surface, a large central

semicircular area on the cephalic surface, and a long caudally-extending worm-like

intercolumnar process on the ventral surface are completely separated from the rest of

the cerebellum to form the lob/is imticMs. Stroud, following the precepts of Burt Wilder

as regards nomenclature, calls this lobe by the mononym "■ preramus.'" Kuithan calls it

" Vorderlappen" Thus both Stroud and Kuithan, on embryological grounds, support

the suggestion, which I am advancing for comparative reasons, to separate the region in

front of Xhefisswa prima from the rest of the cerebellum as a natural primary division,

which we may appropriately distinguish as the lobus anticus.

The part of the cerebellum which is left after removing the lobus anticus and the two

lobi Jlocculi is the most complex part of the organ, and, as its subdivisions are not so

clearly defined as those of the other lobes, opinions are divided as to tlie most natural

method of subdivision. We may at once neglect Kuithan's subdivision, because he

fails to recognize the ujiper part of the parajlocculus in the Sheep, but simply calls it

vermis lateralis, without suggesting any homology. Otherwise he says little about the

xe^\orihQ\\m(\.t\\efissnra prima. Stroud calls the whole of this area " postramus." He

calls each of the lateral areas of the "jwstramns " a ^j^'fcww?, and divides each into a

" prep ileum " and a " postp) ileum."

The objections to the acceptance of tliis suggestion of Stroud are twofold. In the first

place, this mode of dividing up the lateral areas is not sufficiently constant in the lowlier

mammals to be fundamental, and if it were it is not sufficiently comprehensive ; in other

words, this lateral area falls more naturally into three (or perhaps four) subdivisions. In

the second place, tliere is, in the area behind the fissura prima, a fissure of higher mor-

phological importance and of greater stability than Stroud's " interpileur sulcus." This

fissure I shall call i\\e fissura secunda, because, of the fissures that cross the mesial plane,

it is second in importance only to the fissura jirima. The fissura secuuda corresponds to

the cleft which separates the pyramid from the uvula in the human brain. Stroud calls

it the Mt'wiar SMfc?fs, and demonstrates its early appearance in the Cat, for be confesses

(p. 106) that be does not know wbethcr it or tlie fissura prima develops the earlier.

Kuithan's figures show the precocious appearance of the fissura secunda soon after the

■fissura prima in the Sheep. But my main reason for adopting this fissure as an interlobar

boundary is a comparative one. In all the various types of cerebellum which form a

complete gradation from that of Notoryctes to that of Man, this fissure is constant, and

separates a small caudal area of cerebellum from the complex central mass. Its mor-

phological importance is undoubtedly considerably inferior to that of the fissura prima,

bvit to the student of the lowlier mammalian tvpes the adoption of ihe fissura secuuda as

an interlobar fissure will facilitate descriptive work very considerably.

I propose, therefore, to divide the mesial or " interfioccular '" area of the cerebellum

THE BEAIN IN THE EDENTATA. 305

into three azygos lobes by means of the two fissures prima and secunda. These three

lobes will be called lohus antlcus, loltiis centralis, and lobus posticus respectively. The

coHA' enience and clearness of the term " centralis " induce me to adojit it, for there is

little danj^er of this term ever being confused with that denoting the small " lobiUus

centralis," a term api^lied in human anatomy to the cephalic part of the lohus anticus.

The Jissnra secimcla cuts deei^ly in a horizontal direction into the cerebellum in the

mesial plane, from a point upon the caudal surface a short distance above the sharp

ventro-caudal angle. It follows a transverse course of 10 mm., i. e. about 5 ram. on each

side of the mesial plane, and then bends suddenly at a right angle into the vertical

direction, and reaching the ventral surftice it extends in the cephalic direction as far as

the posterior medullary velum, /. e. into close proximity to the cerebellar peduncles.

By means of this 2:)eculiar fissure, a little mesial tongue-like process — the lohus posticus

— is completely cut off from the rest of tlie cerebellum.

ThQ posterior lohe is divided by a deep fissure upon the ventral surface into two main

groujis of folia. The anterior of these is a small insignificant group of three folia

intimately associated with the posterior medullary velum and corresponding to the

nodulus of human anatomy. The rest of the lobe is a large, complex, triangular mass,

which includes the postero-ventral angle of the cerebellum and corresponds to the uvula

of human anatomy.

The lohns centralis constitutes the chief part of the cerebellum. It is limited in front

by the fissura prima, behind by the Jissura secunda, and laterally by the Jlssurce Jlocculi.

It is a large, irregular, and complicated region, which, in the exuberance of its growth,

has bulged obliquely forward and laterally on each side, and, wedging its way between

the lateral part of the lohus anticus and the front of the lohus Jlocculi, it has extended on

the anterior surface as far in the ventral direction as the columna cerehelli.

In the caudal direction it shows a similarly exuberant growth, for the lateral parts of

the lohus centralis bulge downward upon the caudal surface of the organ between the

lohus posticus and the lobus Jlocculi.

Thus the central lohe, which is comparatively narrow in the mesial j)lane, expands

considerably in its lateral parts and embraces the lobus Jlocculi.

This expanded lateral part of the lobus centralis on each side may be distinguished

as the area crescens, for it will be found that in the higher mammals it is the exuberant

increase of this part of the cerebellum which is the main factor in the evolutionary

process.

The most caudal part of the lohus centralis in the mesial plane is naturally separable

from the rest as a distinct wedge-shaped sector, which is probably the homologue of the

pyramid of hrmian anatomy. In Orycteropus Wixs, pyramid does not appear to belong to

the central lobe, but to be quite distinct from it ; and we shall see subsequently that in

many mammals the pyramid is quite a subsidiary twig of the large tree-like branch

which forms the central lobe. This view is, moreover, supported by developmental

evidence, in the case of animals the pyramid of aa hich is independent in the adult.

"We shall see later that in the simpler cerebellum of small mammals the pyramid is

directly continued in the lateral direction, on each side, into the caudal extremity of the

SECOND SERIES. — ZOOLOGY, VOL. VII. 50

366 DR. G. ELLIOT SMITH ON

paraflocc/rhs dorsalis, by menus of a liand of grey substance. This arrangement also

exists in Orycteropns, but the larger dimensions of the area crescens have hidden the

connecting baud. Bulging downward upon the lateral side of the ^lyramid, the area

crescens seems to cut off the pyramid from all connection with the lateral parts of the

organ ; but if the area crescens be raised, a narrow flattened band will be found arching

downward from the pyramid into continuity -oith the paraflocculus dorsalis.

We are now in a position to understand the course of ihe fssKrafloccuIi, of which

little has been said. The floccular fissixrc separates the floccular lobe from the area

crescens of the central lobe. It begins anteriorly at the columna cerebelU, proceeds

in the caudal direction around the lateral pole, then obliquely backward on the

dorsal surface of this pole tintil it reaches the posterior surface ; it then proceeds

obliquely toward the mesial plane, at the same time inclining doAYnward ; after

reaching the ventral margin of this surface it bends sharply upward on the mesial

side of the area crescens, and crosses tlie mesial plane as the tipper limiting furrow (<?)

of ihe pyramid.

The area crescens is divided into three chief subdivisions by means of two deep

fissures which begin at its lateral margins and extend toward the mesial plane. The

more anterior of these fissures, which we may distinguish as a, begins on the anterior

surface of the cerebellum, in close proximity to the point where the Jissura prima reaches

the columna cerehelli. From a surface-view the two clefts, Jissura a and the Jissura

prima, would appear to arise from a common stem, but a submerged folium really

separates them in the whole of their extent. The fissure a. extends vertically, and hence

it diverges from ihe Jissura prima. The two fissures thus come to be separated by an

anterior district which we may call the area A. The fissure a ascends vertically on the

anterior surface, and then proceeds directly backward on the dorsal surface, and then

arches mesially, and at a point about 0 mm. from the mesial plane it joins a much

shallower transverse fissure, Avhich we may for convenience of description regard as part

of the fissure « (fig. 29). The region included between the fissure a and the Jissura

prima consists of the two laterally placed, oblique fusiform areas A and a mesial quadri-

lateral area. The latter is joined to the area A on each side by a narroAv neck.

A second very deep fissure cuts into the lateral border of the area crescens, and this

we may distinguish by the letter h. The fissure h starts from the postero-lateral

margin of the area crescens at a point w^hich roughly corresjionds to the middle of

ihe Jissura Jlocculi. It cuts transversely into the central lobe, but suddenly comes to

a termination at a point about 5 mm. from the mesial plane. At this point we find a

shallow depression, which we may call the medullary area, for reasons which will be

evident later. For the sake of convenience of description, we may denominate a shallow

fissure which crosses the mesial plane at this point as part of ihe Jissura b.

By means of the fissures a and b the broad expanded lateral part of the central lobe,

which we have called the area crescens, is divided into three regions, w^hich Ave may

distinguish as the areas A, B, and C respectively. The area C, the most caudally placed

of the three regions, is a large amygdaloid mass which projects backw-ard between the

lohus Jlocculi, on the late]al side, and the pyramid and lobus posticus on the mesial side

THE BKAIX IX THE EDENTATA. 337

and upon tlie posterioi- suiface of the organ it extends as far as the ventral surface.

Mesially it becomes continuous, by means of a very narrow stalk, with the small folium

which extends across the mesial plane above the pyramid and is included between the

fissures a and c. The surface of the area C is deeply incised by about 12 fissures, which

are obliquely placed and converge toward the mesial stalk.

The area B is by far the greatest of the three subdivisions of the area cresceiis. It is

attached to the mesial parts of the organ by a narrow stalk, composed of a single folium,

which is wedged in between the areas A and C, but it rapidly expands in the lateral

direction and forms a large oval mass, which extends obliquely forward between the lohus

flocciili on the lateral side, and the area A and the lobus anticus on the mesial side, and

reaches as far as the columna cerebelll. The siu-face of this area, which forms the

nucleus of tlie large lateral mass of the cerebelhrm, is deeply scored by numerous fissures,

which converge toward the axis of the area, and ihus this region becomes spHt up into

innumerable folia, which are arranged like the barbs on a feather. The sinale folium

which forms the stalk oi this large mass expands in the middle line to form a little

cuneiform mass whicli is interposed between the mesial continuations of the fissures

a and b.

We find, therefore, that it is possible to divide the lobns centralis, according to the

conventional mode, into a distinct central part, or vernus, and lateral areas. In the

case of the lobus anticus there is no such natural division. And in the case of the lobus

2J0sficus the whole lobe belongs to tlie ceniiis.

The importance of this mode of dividing vip the cerebellum into vermis and lateral

lobes is very much exaggerated by the customary mode of describing the organ.

The bilateral symmetry of the vermis is disturbed by bending to the right side, which

aff'ects the upper part of the pyramid and the adjacent supra-pyramidal part of the

central lobe.

The study of the configuration of the cerebellum as it is demonstrated in a mesial

sagittal section is esj)ecially instructive. In Orycteropus the mesial sagittal section of

the cerebellum exhibits an oblong figm-e with all the angles, except the postero-inferior,

rounded off. The dorsal and ventral surfaces are horizontal and considerably longer than

the vertical anterior and posterior surfaces.

The arrangement of the lobes and their subdivisions, which is exposed in a mesial

sagittal section of the cerebellum in Orycterojius, presents the closest analogy to that of

the human cerebellum. If we overlook the fact that the general shape of the sections

is so different, and that the diameters of the former section are only about one half those

of the latter, we might confidently say that the sections are in all essentials identical.

This fact is so impressive and significant that y\e muy be pardoned for examinins the

points of this resemldance more closely.

We may begin at the velum medullare and lollow the folia in the caudal direction in

the two forms, employing the terms in common use in human anatomy at the present

time (cp. Quain's, Schwalbe's, or any of the ordinary anatomy text-books).

The most caudal part of the velum is thickened by transverse bands of grey matter

to form the liinjula in both brains. The rest of the lobus anticus presents a very close

50*

368 DB. G. ELLIOT SMITH ON

resemblance to the combined lohulus centralis and tlie ciilmen monticnM of the human

brain, and is quite as com]ilex and built ujion the same morj)holo;5ical plan in Orycte-

rojjus as it is in Man. We find that the area which lies behind the fissiira prima

{prceclivctUs of Man) is strikingly similar in the two forms. This large area is divided

into four primary divisions in both cerebella. These fissures are respectively (adopting

Schafer's nomenclature in Quain's 'Anatomy ') the sulcus 2n'<xgracilis, corresponding to our

fissure c; the sulcus prcepyramidalis, corresponding to owr Jtssirra secimda; and the sulcus

postnochilaris, corresponding to our fissure d. The resemblance between the several areas

into which these fissures subdivide the region behind the Jissiirn p)rinia is extremely

close, and is carried even further than the general shape of the main divisions. The

large triangular mass between the Jissura prima and the fissiire c is subdivided into three

parts by the relatively shallow fissures a and b, just as the analogous region in the human

brain is split up into the cUmis, the folium cacuminis, and the tuber valvulce by the sulcus

postcUvalis and the sulcus Iwriznntalis magnus.

The area included between the fissures c and d in the brain of Ortjcteropus presents

exactly the same shape which has earned the name j:)^'*'''"'^*^^ for the apparently analogous

region of the brain of Man.

It is unnecessary to do more than refer to the uvula nxi(inodMlui<, for they are obviously

homologous in the two cerebella.

In the whole section, then, we find a most striking and surpiisingly close resemblance

between the two cerebellar types. And, even more surprising still, the degree of com-

plexity of the mesial section in Orycteropus is certainly no less rich than it is in Man.

It is uot surprising, when we find this parallelism between two such distantly-related

foi'ms as Orycteropus and Homo, to find that the same pattern is widely prevalent

among the lai'ger mammals, being found equally in the Carniwra, TJngidata, and Myrme-

cophogldce.

A mere resemblance between two sagittal sections, even when it is so close and so

apparently beyond question as are those of Orycteropms and Jlomo, is not, however, a

sufficient guarantee of the morphological identity of the similar parts. We need some

further corroborative evidence before we can admit their homoplasy. This evidence is

to be sought in the behaviour of the lateral extensions of these central parts in a series

of cerebella, and also in the develojmiental history of the parts in the bi-ains under

comparison.

The behaviour of the lateral extensions of the lobas auticus and the lobus posticiis

arapljf confirms their suggested homologies in the two forms, and although we cannot

siTpply the embryological evidence to sujiport this view, we can have little hesitation in

adopting it as accurate.

While there can be little doubt as to the homologies of most of the segments which

present an analogous arrangement in the two sagittal sections, we must confess to grave

doubts as to the homology of the j^yramid of Man with the part we have tentatively called

by this name in Orycte7'opus. If w^e admit that the appearance of a sagittal section is

valid and sutficient evidence, Ave would not hesitate to state the homology at a glance,

for the disposition, the relationships, and even the shape of the two parts are exactly

THE BRAIN IN THE EDENTATA. 369

alike. Kuitliaii has unhesitatingly called the analogous part of tlie Sheep's hraiu by

the name ^' fijramid^'' although its disposition agrees exactly with the corresj)onding

part in Orycteroptis. In the meantime I shall use the term pyramid witli the

reservation that the validity of its homology with the similarly-named part of the

cerebellum in Man remains to be joroved. This point can be satisfactorily settled

only by embryological investigation, and neither Kuithan nor Stroud has attempted

to solve the problem.

After we have learned how closely the cut surface of the cerebellum which is exposed

in a mesial sagittal section in Ori/cteropus agrees with the arrangement in the brain of

Man and the Sheep, it is not surprising to find the closest agreement between Orycteropiis

and Myrmecopliucja in this respect. So exact is this resemblance that fig. 29 would

need only very slight modification to represent a section from the Great Ant-eater.

But the agreement is not confined to the mesial section. For in the behaviour of the

lateral extensions of the parts we again find a close resemblance between the two organs.

In Myrmecophaga the lateral parts are not so full and rounded as they are in Orycte-

ropns, and hence the organ approaches nearer to a lozenge-shape. The descriptions we

have given of the Jissiira prima and the lobiis loilicits in Orycteropiis apply equally well

to Myrmecophacja. The lohus flocculi is relatively smaller in the Ant-eater, and does

not rise nearly so high as it does in the Aard-vark. Both the dorsal and ventral parts of

the j^araflocculus are horizontal worm-like l)ands, and the dorsal part especially is much

narrower than it is in the Aard-vark. In addition it is much simpler (fig. 7). The

fiocculus is more exposed than it is in the Aard-vark.

The area A of the lohus centralis is moreover somewhat simpler than it is in

Orycteropiis. As a result of the smaller size of the lobus flocculi, the area B overlaj)s

it to a greater extent than is the case in the Aard-vark. The area C closely resembles

the corresponding region in our type, but the mesial region with which it is connected

is submerged.

The lateral extensions of the pyramid have more obvious bands than is the case in

Orycteropus, and thus they appear to form the lowermost folia of the area C.

T'he cerebellum of Tamandiia is smaller and simjiler, and jn'esents several slight

differences to mar tlie otherwise close resemblance to the organ in the Great Ant-eater.

The main features of the anterior lobe are imchanged, but its structure is simplified by a

reduction in the number and complexity of the folia.

The general features of the lobus flocculi resemble those of Myrmecophaga, but the

band connecting the posterior extremity of the dorsal part of the paraflocculus to the

pyramid now appears to be quite aborted. In a superficial view the folia of the posterior

extremity of the paraflocculus appear to be in series with the folia of the area C of the

lobus centralis. The posterior extremity of the ventral parafloccukis is peculiarly

modified to form a projecting tuft of about six folia on a common stalk. This is lodged

in a special cavity of the periotic bone, and in the loose nomenclature in common use

would be called simply " flocculus."

The area A of the central lobe is a single folium which is cut up by a few shallow

sulci, not visible on the surface. The area B is a simplified copy of the corresponding

370 DR. Cr. ELLIOT SMITH ON

area of tlie Great Ant-eater. Tlie pyramid is now simply a branch of the main stem of

the central lobe.

In size and general appearance, the cerebellum of Tamandtia is not unlike that of

Canis. This resemblance is also borne out to a considerable extent in the detail of most

parts of the organ, but the fioccular lobe presents a number of differences. The only

one of these which we need mention here is the fact that the projecting part of the lobe

is formed from the junction of the dorsal and Acntral parts of the parafiocculus, and

hence is not strictly homologous to the projecting part in Tamandua, which is the most

caudal part of the parajlocculus ventralls.

In spite of the extraordinary difference in size in the cerebella of the Sloths, they present

a close structural agreement. The much smaller organ of Bradypus is slightly simpler

than that of Choloepus, but it will suffice to describe the latter. There are very

considerable differences between the appearance of the mesial sagittal sections of the

brain represented in figure 18 and one in the stock of the College of Surgeons. The

latter is larger and much more richly foliated, and, by contrast, the simplicity of the

brain represented in figure 18 suggests immaturity. In the latter the pyramid is a very

small branch of the central lobe, and forms a peculiar lip which overlaps the medulla

oblongata and quite liides the uvula from view. In the specimen in the College of

Surgeons the uvula is much larger and forms the ventro-caudal angle of the hemisphere,

and the pyramid is a large and independent lobule.

The mesial section has lost the quadrilateral shai)e it has in the other Edentates we

have considered, being now much less angular. A large lobiis Jlocculi forms a large

mass on each lateral pole. This 'fioccular lobe has a similar appearance in the two

Sloths (figs. 11, 12). The pjarajloccuhis dorsalis consists of a large inverted V,

composed of deep but simple folia. The parajlocculus ventralis consists of simj)le angular

folia filling up the space between the limbs of the V. There is a typical anterior lobe,

but it presents a quadrilateral shape from being wedged between the two large fioccular

lobes. The area A of the central lobe resembles that of Tamandau. The area B in

Cholcepus is expanded to a much less extent than it is in Tamandua, and in Bradypus

the expansion is even less. As a result, the whole central lobe is simpler and has a more

distinctly quadrilateral shape, which is increased by the large fioccular lobes which

form its lateral boundaries. The area B is only about three times as broad as the central

area, with which it is in direct and iminterrupted continuity. Consequently there is

merely a very simple arrangement of radiating fisstires in the area B, which forms a

marked contrast to the feather like grouping in the Ant-eaters. The area C is also much

simpler, and, as a result of the lesser expansion of the area B, much broader than

it is in Tamandua. The pyramid is connected laterally with a group of very broad

folia which proceed to the dorsal parafiocculus. These folds may be regarded as part of

the area C.

The posterior lobe needs no comment, as it is as constant as the anterior lobe.

In section the cerebellum of Manis is definitely quadrilateral, but in structure it is

very simple and not unlike the organ in Bradyjjus, excepting that the fioccular lobe is

relatively smaller in the Pangolin.

THE BKAIN IN THE EDENTATA.

371

The cerebellum in the Armadillos apjiareatly differs iu such a marked manner from

that of the other Edentates that we must consider it in more detail.

I shall describe the cerebellum of Xontti'iis, which is typical of the family.

The cerebellum of Xetmnis, which is apparently constituted so differently from the

cerebellum in the other families of Edentata, is really built upon the same plan. Its

most marked peculiarity is due to the fact that the lobus centralis extends forward like a

hood and completely hides the lobus aidicus from view. But if we remove the cerebral

hemispheres and the anterior part of the brain-stem, and examine the anterior surface of

the cerebellum (fig. 30), we shall find atypical anterior lobe bounded by Sijissura prima.

tlocCuIUB

Corp. quadngem

Anterior surface of cerebellum of Xenunis. Nat. size.

The right half of the meseucophalon is delineated hi situ.

fiss. prima .

lob. central.'

fies. secunda

lob. post.----j

medulla oblong.--

Fis. 31.

area B

•paraflooc.

area C

Eight half of dorsal surface of corebelhiin of Xi:nufus. Enlarged |- diam.

X. Grey band connecting 2^1/romis to pnrafloc-nhi^ ihirsalls!. ij. Bare area of medullary substance.

area C

Lparaflocc.

flocculoa

lob. post.

Caudal surface of cerebellum of Xi^nxirui. Mat. size.

372 DE. G. ELLIOT SMITH ON

,fis3. prima

,.- paraflocc. dors,

lob. ant.

_■■ ••paraflocc. ventr.

k

. • , •. pons Varol.

flocculua ' '

nerv. V.

Lateral (riglit) surface of cerebellum of Xcniu-us. Slightly enlarged.

The fasura prima is a simple arcuate fissure strictly limited to the anterior surface.

It limits a simple anterior lobe which is subdivided by a few arcuate fissures (fig. 30).

The lohus jloccidl is a prominent and much more independent part of the cerebellum

than it is in the other Edentates. In other words, it is not packed so closely.

The paraflocculus^ is divided, as usual, into dorsal and ventral parts (fig. 33). The

paraflocculus dovsalis is a narrow worm-like series of simple folia, which caudally become

continuous witli tAvo broad grey bands (fig, 33, .r), which arch mesiaUy and then upward to

become continuous with the pyramid, which is here a small and insignificant twig of the

central lobe. The cephalic extremity of the dorsal paraflocculus becomes serially

continuous with the paraflocculus ventralis, which is composed of much deeper and

broader folia than tlie dorsal segment (fig. 33). Upon the mesial side of the

ventral part of the paraflocculus we find the flattened cak(iA\\.Q flocculus (figs. 30, 32,

and 33), which occupies the interval between the medulla oblongata and ventral part of

the paraflocculus, and projects lurther backward («. e. in the caudal direction) than the

latter. The flocculus is connected to tlxe nodulus {i. e. the foremost part of the posterior

lobe) by means of a baud of medullary substance. The posterior lobe is a very simple

median band of grey substance which is subdivided into two parts, nodulus and uvula, by

a deep transverse fissure, and in addition it is subdivided by three or four shallow furrows

(figs. 33 and 31). It is separated from the small '= pyramid " and its lateral connections

by a shallow arcuate fissura secunda (fig. 32).

Practically the w^hole of the dorsal surface of the organ is formed by the central lobe,

which has extended forward over the anterior lobe. The lobe appears to have been

stretched in this process and the grey matter separated into a median band and two

lateral areas, which are separated by regions in which the medullary matter is exposed

(fig. 31, y). The median band is subdivided into about ten simple folia by a number of

transverse shalloAV furrows. The subdivision of the area cresceiis or lateral part of the

central lobe is very imperfect.

The representative of the area A consists of the simple narrow foHtim which overhangs

the anterior lobe (tig. 30). Its lateral parts are quite hidden in iha flssura prima.

The area C consists of the obliquely-placed lateral grey band Avhich begins at the lateral

extensions of the 2:)yramid (figs. 31 and 33), and extends upward to the antero-lateral

corner of the organ. It is subdivided by about ten simple transverse fiu'rows. Wedged

THE BKAIN IN THE EDENTATA,

373

in between the areas A and C we find at the dorso-lateral corner of the anterior surface

(fig. 30) a little group of about six folia wliicli converge in a mesial direction toward the

lateral corner of the medullary area on the dorsal surface (Bg. 31). The resemblance

between the cerebellum in Xeuurus, the Rodent Lepus, and the Marsupial Dasi/urus is

very striking.

In Dasi/jms we find that the lobits centralis does not cover the lobus anticus so

completely as it does in Xeuurus. Thus the Jissura jirlma and part of the anterior lobe

become visible ujion the dorsal surface. The area B of the central lobe, instead of being

almost confined to the anterior surface, now forms the extreme lateral angle of the dorsal

surface. la other words, the organ becomes much more like the cerebellum in the

JIanidce and BradypocUdcB. We see the same process occurring in tlie Rodents. Eor

while Lepus is like Xenurus in this resjject, we find that in Atherura * a cei'ebellum in

many res^^ects like that of Ta-maudua is found.

In Dasi/pus \\\<i parafloccidus dorsalls is relatively larger than in Xenurus.

In Clilami/dophorus the cerebellum presents a very peculiar appearance (fig. 15). It

is a flattened plate closely applied to the vertical posterior extremities of the hemispheres,

and appears at a cursory glance to be utterly unlike any of the other forms we have so

far considered. But ^vhen we study its anatomy more closely, by means of sections, we

find that it is merely a simplified type of the cerebellum of Xenurus which has become

flattened between the vertical occipital plane of the skull and the posterior extremities of

the hemispheres. An exactly similar flattening takes place in the Marsupial Notoryctes.

A lohus JloccuU composed of about six simple foHa is placed like a buttress against the

lower part of each lateral edge of the cerebellum (figs. 15, 35, and 30).

Yxs. 34.

- lob. central.

fiss. prima

lob. aut.

vel. meduUare »v--v\-ma

-Bss. secunda

. lob. post.

Mesial sagittal section of cerebellum of Chlamydophorus. Enlarged 3 (liam.

FiK. 3.5.

lob. post.

Anterior surface of cerebellum of Clilaiuydophorus. Enlarged 2 duira.

* F. G. Parsons, " On the Anatomy of Atherura africanu," Troc. Zool. Soc. London, 189-1, p. 087, figs. .5 & 6.

SECOND SERIES. — ZOOLOGY, VOL. VII. 51

374 KK. G. ELLIOT SMITH ON

In a mesial sagittal section (fig. 34) we can correlate the organ with that oi Xenitru n

The dee.]) Jissura 2}riwa cuts into the anterior surface and sejoarates the anterior lobe from

the central lobe. Upon the anterior surface (fig. 35) we find the anterior lobe bounded

by the semicivculeiv Jissura prima and subdivided by a few subsidiary sulci.

riff. 36.

.fiea. eecuDda

lob. poBt.

medulla obloDg.

Caudal Burfaeo of brain of Chlamtjdophoi-as to show the cerebeUum. Eiilargetl 2 diam.

Toward the lower part of the posterior surface we find the /issttra sectmda separating

the small posterior lobe from the central lobe. In a view of the posterior surface (fig. 36)

we see this fissnra secunda as a small semicircle. A few shallow fvirrows begin at the

lateral margin and extend for a short distance toward the mesial plane.

The meaning of all tliese data will be In-iefly discussed in the conchiding part.

General Considerations.

In reviewing all the data Avhich I have been able to collect and examine in the fore-

going pages, the many imperfections of the record are only too patent. Our knowledge

of the adult brain, even so far as its macroscopic features are concerned, is far from

jDcrfect, and we have only the merest scraps of information concerning its developmental

history in the different genera. Yet this knowledge, in spite of its fragmentary nature,

is not altogether lacking in importance. For if it does not j)ermit us to positively localize

the members of this group in the mammalian series, the evidence of cerebral anatomy

enables lis to definitely refute many beliefs concerning the position of the Edentata which

even the wealth of palseontological discovery Avithin recent A^ears has been unable to

shatter. In addition to this negative A^alue, the testimony of the brain indicates with

some degree of proliability the direction in which we must look for the nearest allies of

the heterogeneous group Avhich we are discussing.

"While recognizing that the evidence of cerebral anatomy often possesses a decisive

taxonomic value, we cannot be blind to the fact that in many cases, without the sujiport

of the testimony of other anatomical systems, we could only vaguely hint at the position

of a mammal from the character of its nervous system. Tluis, while we attach considerable

importance to the exact configuration of the brain in Myrmecophaga, we could not

suggest any kinshijj of tlie Armadillos with this Ant-eater uj)on the evidence of its

cerebi'al anatomy, if we were not aware of the peculiar Xenarthrous nature of its vertebriB.

At the same time it is quite possible that, if we were acquainted with the pallial configu-

ration of Friodon, w^e might be able to say decisively that the Giant Armadillo is a

relative of the Great Ant-eater upon the evidence of the brain alone. T'he merest tyro

could recognize at a glance the brain of a member of either of the great Ungulate or

THE BRAIN IN THE EDENTATA. 375

Unguiculate groups, but the task of deciding whether some of the smaller mammalian

brains belong to the Insectivora, E-odentia, Chiroptera, or possibly Edentata, would tax

the ingenuity of the most learned anatomist. However much importance w^e may attach

to the value of the evidence presented by the brain, we cannot afford to disregard the

testimony of the other systems wpon which, in many cases, we must rely for decisive

data for classificatory purposes.

In attempting to form a just estimate of the value and full significance of our data, we

cannot take too wide a view of the field of enquiry. We must strive to clearly appreciate

the distinctive features of the mammalian brain aud the factors which are at work in

modifying it, before we attempt to estimate the taxonomic value of the features of any

given type of brain. The brain indicates, perhaps more thau any other system, the

immense superiority of the mammal over all other forms of life. For, in virtue of the

possession of such an organ, the mammal is able to very readily adapt itself to more

comjilex conditions of existence than is possible among any other class of animals, without

the most profound modifications of structure which take extremely long periods of time

for their accomplishment. Mammals may, on the other hand, in comparatively very

short periods of time and by means of changes which are so slight as not to fundamentally

interfere with the distinctly mammalian type of body, adapt themselves to almost any

mode of aquatic, terrestrial, or aerial life such as among other vertebrates it takes whole

geological epochs to acquire, and then only at the expense of most fundamental modifi-

cations of their bodily structure.

The part of the brain in which this superiority most strikingly manifests itself is the

cerebral hemispheres. In all vertebrates the incoming olfactory nerves are inserted into

an olfactory bulb, which is connected by a peduncle with the cerebral hemisphere, which

at first consists of little else than a small, simple, unditferentiated basal ganglion. At a

very early stage in the evolution of the brain, we can recognize the primordial

elements of the rhinencephalon making their apjiearauce. Even in the Dij^noi and

Amphibia we can recognize a difierentiation of the mesial wall of the primitive liemi-

sphere into the paracommissnral body and the forerunner of the hij)pocampus, while on

the basal and lateral aspects the undiff'erentiated primordial tuberculum olfactorium and

lobus pyi'iformis may be localized. In tlie Sauropsida the primordial hippocampus and

pyriform lobe advance a further stage in the process of differentiation, although they ai'e

still far removed from the final stage of elaboration which we find in even the lowest

mammal.

It is only in the Mammalia that the pyriform cortex becomes fully differentiated and

the hipjiocampus assumes its typical characters. Now, for the first time, the margin of

the liippocampal formation becomes strangely modified to form the fascia dentata, and

in association with this the rt^gion undergoes a ])eculiar mechanical involution which

gives rise to the hippocampal fissure. These two regions — the pyriform lobe and the

hippocampus — not only reach the acme of their elaboration within the Mammalia, but

they increase considerably in size, so that in the early mammal they form a large and

complicated mechanism in which olfactory impulses are received and possibly blend with

the impulses of other sense-organs.

51*

370 DR. G. ELLIOT SMITH ON

These peculiar changes which have bcca just briefly outlined are distinctive of the

Mammalia ; they are never found oixtside the class, and there is no mammal in which

tliese features are lacking. Moreover, these changes appear to have practically reached

their consummation even in the lowliest mammal.

Although the rhinencephalon is thus much larger and much more highly developed in

the mammal than it is elsewhere, it at the same time takes a relatively much greater

shai'e in the fonnation of the cerebral hemisj^here in the non-mammalian vertebrates.

The simple primordial hippocampus of the reptile forms not only the greater part of the

mesial Avail, but also a large part of the dorsal w^all or roof of the hemisphere ; and its

lateral margin is thus brought into proximity with the simple representative of the pyri-

f orm lobe which forms part of the lateral wall. All that separates tliese two parts of the

rhinencephalon in the reptile is an insignificant area of simple cortex on the dorso-lateral

aspect of the hemisphere. It is difficult to appreciate the fact that this apparently

unimportant and almost undifferentiated patch represents the forerunner of that highly

specialized and elaborately complex cortex which we know as the pallium, and whicli

in the mammal produces such profound and far-reaching modifications and attains to a

morjjhological importance which exceeds that of the rest of the nervous system.

In this imperfect sketch of some of the salieiit features in the evolution of the cerebral

cortex we have wandered some distance from our main theme, in order to emphasize the

fact that the pallium is practically a new structure in the mammal : it is something that

has been added to the old Saurian brain, and immediately exercises so marked an influence

upon its possessor that it is perhaps not an exaggeration to say that the possession of a

pallium made mammals possible. Before its appearance the central nervous system

might be compared to a series of autonomous governments, of varying importance and

influence, united into a harmoniously working federation, witli no very decided centralized

control beyond the slightly dominant sway exercised by the insignificant cei'ebral hemi-

spheres. In the mammal this federation comes under the domination of the almost

absolute power of the dictatorial i:)allium. The pallium, in a sense, represents within

itself the whole body, because nerve-paths proceeding from all regions of the body

ultimately lead to the pallium, which is the Rome of the neural empire ; but it also

dominates and controls the whole of the nervous system, and through it the whole of

the body.

It is of the utmost importance, therefore, to study the features of this organ, which

may truly be regarded as a reflection of the whole body. Keeping constantly in view

the fact of its recent appearance, its obvious influence on the rest of the organism,

and the multiplicity of factors which determine its size and configuration, we may

the better ajipreciate the meaning of its changing features which we are about to

consider.

But before doing so we must briefly discuss the nature and constitution of the

pallium.

The governing organ of the submammalian brain is probably the simple basal ganglion,

which is generally influenced in all probability to a predominant degree by the preco-

ciously developed olfactory areas of the hemisphere. In the mammal the development

THE BRAIN IN THE EDENTATA. 377

of the pallivim (probably by differentiation from the basal ganglion) provides a cortical

area with a free scope for expansion, in connection with which paths from all the lower

sensory centres become established. Thus the primitive jmllium becomes a field in which

the retina, the sensory lining of the internal ear, and all the tactile surfaces of the body

become represented, so that the impulses of these various senses may meet and mutually

react the one upon the rest. Thus tlie primitive pallium is essentially a "sensory area,"

but it is at the same time a "projection area." Por all of these centres may exercise a

combined influence upon the pallial nerve-cells, from which efferent imjiulses proceed to

the lower executive centres. Complex groupings of nerve-cells are also formed within

the jiallium, representing potential muscular acts of increasing degrees of complexity,

which may become kinetic w'hen the activity of the pallium stimulates, through its

projection-fibres, the lower executive centres in the brain-stem and spinal cord.

The pallium, then, is essentially a place where afferent impulses from all parts of the

body may meet and combine and exert a direct influence itjion the mechanism which

initiates bodily actions. It is for this reason that the mammal is able to execute move-

ments of a more complex order, of greater jirecision and variety — in a word, can

perform more skilful and purposeful acts than the animal without a pallium. The direct

result of this is a marked advancement in tlie development of the limbs in ordei- to

execute the movements which the possession of a ^^allium makes possible. The way is

opened for all kinds of specialization of movements, and the limbs and the otiier

muscular parts of the body rapidly adapt themselves to special kinds of activities.

Following in the train of these neuro-muscular modifications and specializations, the

skeletal and alimentary organs rapidly accommodate themselves to the changing mode

of life of the individual.

The small early pallium may be regarded as being entirely composed of sensory areas,

which rapidly increase in size and complexity, as the intermediate sensory stations, such

as the corpora geniculata and optic thalamus, grow, and produce richer and more abundant

sensory paths to the pallium With the increasing size and complexity of sensory areas

the demand for association-elements wdiicli shall link together in functional unity the

various sensory areas and the various parts of each area becomes imperative. Of neces-

sity, therefore, a new set of elements springs uj), consisting of nerve-cells whose nerve-

fibre processes serve to bring into functional co-operation all the scattered elements of

the sensori-projection pallium. A time comes at an early period in the evolution of the

mammal when the variotrs sensory areas become fully represented in the paUial growth.

Up till this time any variation in the acuteuess of a sense-organ has an imjiortant and

obvious effect upon the size of the pallium.

The diminution or extinction of the visual element in the cortex, such as occurs to a

high degree in Notoryctes, Carysochloris, Talpa, and CJilamijdophoi'Hs, causes a most

profound difference in the size of the pallium, and any interference with the tactile or

auditory acuteuess would doubtless have considerable influence upon the pallial region.

But after the sensory areas are fully represented the pallium still continues to increase

in extent.

Inextricably intertwined with the sensori-projection elements, the association-elements

378 DK. G. ELLIOT SMITH ON

increase in number, so as to unite into a more exquisitely delicate machine the sensori-

projection cortex. The increase in number of these elements causes an insidious growth

of the sensory areas in which they are so intimately mingled with the sensory and

projection elements. But as these association-el emerits increase in number in the

formation of intricate groupings which determine increasingly complex and " skilful "

movements, they extend far beyond the limits of the "sensory " or " projection" areas,

and constitute regions wdiich .Flechsig calls " areas of association."

In an interesting memoir upon the weight of the brain in mammals, Eugene Dubois *

calls attention to and discusses the influence of the size and richness of the sensory

surfaces of the body upon the cei'ebral cortex. Plechsig, who introduced the terms

"■ Projection-centre " and " Association-centre," has shown that the former develop veiy

late in the ontogeny of the mammalian brain ; and the sensory fibres, which are the first

to develop in the cortex, only receive their medullated sheaths after the lower executive

and jjhylogenetically ancient parts of the brain are fully developed.

The facts which we liave discussed above to show the appearance of the pallium for the

first time in the mammal give a demonstration of the late phylogenetic appearance of the

more primitive pallium {I. e. the centres of projection), which is (|uitc in harmony with

their late appearance in ontogeny. The " centres of association " naturally make their

appearance after the " centres of i^rojection " are laid down.

Elechsig says t that in E-odents (the House-Mouse and the Marmot) association-centres

are entirely lacking. In other words, the sensory centres are in close contiguity

(" Sinnesphiire stosst an Sinnesphiire "), so that the whole j^^Hium is one field of

projection. It is difficult to conceive of a large pallial area like that of the Rodents as

entirely devoid of association-elements, and we may with some reason interpret Flechsig's

statements as meaning that the elements of association are not yet sufficiently numerous

to form definite areas beyond the limits of the sensory. Such areas of association

begin to make their apjjearance in the Carnivora, according to Flechsig. The association-

elements which exist in the pallium of tlie Rodent are so intimately intermingled with

the sensori-projection elements that they are not recognizable as such, but go to swell

the dimensions of the sensory or j)roj action areas.

The further discussion of these factors must be deferred until we can discuss the

specific cases afforded by the pallium in the Edentata. In the meantime it is convenient

to briefly discuss the brain-stem and cerebellum.

In the evolution of the mammal the features of the brain-stem change very slightly

in comparison wdth the striking modifications which the cerebral hemisphere undergoes.

Most of the changes which affect the brain-stem are more or less directly associated

with the development of the pallium. Thus the fuller development of the optic thalamus

and the corj)ora geniculata are probably integral factors in the elaboration of the sensory

paths to the pallium. The changes which occur in the corpora quadrigemina are also in

all probal)ility expressions of the same series of changes.

* Eugune Dubois, " Siir le Kappoit du Poids de TEncephale avec la Grandeur du Corps clicz Ics ilammiferes,"

Biilk'tins de la Societe d'Anthropologie de Paris, t. viii. (4" serie) 1897.

t Paul iledisig, ' Gehiru und Socle,' i' Ausgabe : Leipzig, 1896, p. 84.

THE BKAIX IX THE EDENTATA. 379

From the pallium a large mass of projection-fibres arises, and in its downward path

invades the ventral part of the mesencephalon, where it is known as the crus cerebri.

The caudal remnant of the same series of fibres in the medulla oblongata forms the

pyramid. These series of fibres are lacking in the subraammalia, and they increase in

size with the groAvth and perfection of the pallium. On the ventral surface of the hind-

brain a new series of fibres, the pons Varolii, makes its appearance. This is part of the

association-system between the pallium and the cerebellum.

This leads us to the consideration of the cerebellum. This organ shows most marked

signs of advance in the Mammalia, and, next to the cerebral hemisphere, indicates

most strikingly the mammalian superiox'ity of type. It is not improbable that the

important changes in the cerebellum are to a large extent the rcult, j^artly direct and

partly indirect, of the development of the pallium.

In the immediate ancestors of the mammal the cerebellum vvas in all probability a

most insignificant and simple organ, hut pari passu with the development of the pallium

the organ rapidly increases -in size and complexity and becomes intimately connected

•with the new pallium. It is in the highest degree probalile that the sudden and con-

temporaneous progression of tliese two parts of the brain is a single correlated pheno-

menon, and not two coincident but independent acts. Tliere can be little doubt that the

increased activity of cerebellar evolution is one of the expressions of the all-powerful

pallia! influence.

We have already briefly and somew^hat crudely indicated how the possession of a

pallium may permit the mammal to execute movements of greater variety, of increased

nimbleness and immeasurably greater delicacy : in a word, of infinitely gi-eater complexity

than is possible in an animal without a pallium. In the execution of such complex

movements it becomes of the highest importance that the relative activity of the

diff'erent muscles which perform the act should be delicately adjusted and nicely

balanced in order that the complex movement may be " co-ordinate " and purposeful.

It seems not unlikely, taking into consideration the two-fold connections of the cerebellum

on the one hand with the incoming nerves from the sensory surfaces and the muscles,

and on the other with the pallium, that this organ may be a complex executive machine

which in some way controls and renders possible the delicately-adjusted co-operation of

wide groups of muscles.

If such be the case, we might expect the cerebellum to be modified by two, among

in all probability many other, factors.

In the first place afferent fibres which enter the cerebellum from sensory areas or

muscular apparatiis would presumably need a co-ordinating machine proportionate to

their number — or, in other words, the size of an animal would influence the dimensions

of tlie cerebellum.

In the second place, the pallial connection would undoubtedly influence the dimensions

of the cerebellum. For a large and highly diflcrentiated pallium, which betokens complex

potential movements, would presumably need a much richer cerebellar associate than a

small and simple one.

There are unquestionably many other factors at work, such as the possible influence of

380 DE. G. ELLIOT SMITH ON

the eighth nerve on the size of the lobus flocculi ; but, from a careful comparison of a

large series of mammals, these tAvo hypothetical factors impress me as being the most

potent inflaences which determine the size and complexity of the cerebellum.

There is one other point regarding the cerebellum which does not directly concern

us in this memoir, but may be mentioned en passant. The growth of the cerebelluui is

almost purely an increase in the superficial extent of the cortex, for, so far as we are

aw-are, the cerebellar cortex does not appreciably advance in the richness of its histo-

logical elaboration in the Mammalia. In other words, the resultant nerve-fibres do not

become appreciably more abundant per unit of surface area. Therefore the problem of

the mutual adaptation of the rapidly increasing cortical sheet, which is growing in terms

of the square, to the proportionate increase of tlie white or medullary core, which from

the nature of the case must grow in terms of the cube, becomes much more purely

mathematical than is the case in the cerebral cortex. Consequently the surface of the

cerebellum becomes exceedingly comidex in order that the surface of the medullary

matter may approximately be equal to that of the cortical matter. In a large mammal

the cerebellum is much larger, and correspondingly more complex, than it is in a smaller

mammal of the same family. AVhile all parts of the cerebellum share in the increase,

its effects become especially noteworthy in the region which I have called " area

crescens." Among tlie factors which cause the rapid expansion of the area crescens,

liowever, the prllial influence takes a predominant share. A glance at the cerebellum in

the Primates conclusively demonstrates this.

In Chlamydophoriis we find a small and simple cerebellum which is constructed

according to the same plan that ])revails in many members of the Rodeutia and

Chiroj)tera, and in most Insectivores and Marsupials. There is the most remarkable

apparent resemblance between the general shape of the organ in Notoryctes and

ClilamydopliorKs. But we find a much higher degree of complexity in the Edentate than

in the Marsupial, A\hich is all tlie more impressive when Ave consider the similar modes

of life of these two animals, and their not dissimilar bodily dimensions. Even in the

much larger Marsuj)ial Perameles the cerebellum is not so richly folded as it is in the

small Ch lamydophorns.

In Xenurus we find a cerebellum conforming to the same type, and quite as highly

elaborated as that of the Eabbit, and in tlie larger Armadillos (such as Basypus) we find

the same kind of progressive uncovering of the anterior lobe as in certain Eodents *.

This demonstrates the gradual transition from the simpler type of flattened cerebellum

to the more complex type found in all the other families of Edentata, as w^ell as in the

Ungulata and CarniA^ora.

This plumper type of cerebellum with an exposed anterior lobe may possibly represent

a higher type of cerebellum. We find that it is gradually attained in the Armadillos as

the animal increases in size, i. e. as the somatic factor increases. It seems not improb-

able, however, that some other factor, such as the size and degree of complexity of the

pallium, enters into this change. Por in the Kangaroo (MacrojJiis), in which the somatic

* Vide Parsons's figures, op. cit., Proc. Zool. Soc. London, 1894, p. 687.

THE BEAIN IN THE EDENTATA. 381

factor must be mucli greater than it is in any Armadillo or Rodent, we still find the

anterior lobe covered by the hood-like central lobe. In view of these facts and the

marked contrast between the cerebellum in Chlamydopliorus and. Notori/ctes, we are

justified in attaching some importance to the degree of development of the cerebellum as

an index of the status of its possessor.

The enormous growth of the " area crescens " of the central lobe in the Primates,

and the very different configuration and size of the corresponding part of the cerebellum

in the Monotremata, show us that there is some other very definite factor besides

bodily dimensions which determines the size of the cerebellum. The quantity and

quality of the jiallium undoubtedly have a marked effect upon the proportions of the

cerebellum.

If we regard the evidence of the cerebellum as having a definitive taxonomic value—

and in view of the configuration of this organ in Monotremata and Primates, in comparison

with the large group of other mammals, it is difficult to do otherwise — then we must

attach some importance to the extremely close resemblance in configuration and pro-

portions which exists between the cerebellum of the Ant-eaters and Aard-vark and of

the Carnivora and Ungulata. The fact that such a highly specialized organ as the

cerebellum should develop along such exactly analogous lines and attain such similar

proportions in these different groups of animals most conclusively shows, when we

remember how wide a scope for variation there is, that here we have an instance either

of a most remarkable case of convergence or parallelism (which is exceedingly improb-

able), or an imassailable indication of the close genetic relationship which exists between

the Edentates and the commoner quadrupedal mammals.

The idea of separating the Edentata from such other mammals as the Hodentia,

Ungulata, and Carnivora, implied in the introduction of the term " Faratheria," or the

belief that " they suddenly shot up from the Prototheria " *, is entirely shattered by the

evidence of the cerebellum, even if we had not the testimony of the other anatomical

systems to the same jDui-pose.

Am.ong the extinct Armadillos we find in Eutatus a cerebellum of the simpler

Armadillo-type, while in Glyptodon we find an enormous cerebellum which probablv

resembled that of Dasyims.

It is an interesting problem to determine what may have been the reason for a

cerebellum of such huge dimensions in Glyptodou, for the organ is as large as a cerebral

hemisphere. While the pallial factor must have been ver}^ slight, it may be that the

somatic factor explakis the large dimensions of the organ. For it is conceivable that an

animal of such large proportions would need a large organ to co-ordinate its great

muscular system, even though the commanding pallium, which renders such a co-

ordinating mechanism necessary, should be so diminutive.

In describing the brain of 3Ii/rmecophu(ja I had occasion to call attention to the

undoubted fact of its being fashioned in the likeness of the Carrdvorous type. At the

same time it was shown from Max Weber's statistics that Carnivores of similar body-

* \V. K. Parker, ' Mammalian Descent.'

SECOND SERIES. — ZOOLOGY, VOL. VII. 52

382 DE. G. ELLIOT SMITH ON

weight possess a much heavier braiii. We have unfortunately ojily a single record of the

brain-wciglit in Tmnandua : — a Tamandiia tctradactyla, 2 , weighing 1168 gr., has a brain

of 17'35 gr.* This is an extremely higli brain-weight for an animal of this size, far

exceeclii]g that of any of the E-odentia, Chiroptera, or Marsupialia of similar size, although

it is still much below the Carnivore. Max Weber, who is extremely careful in stating

when liis measurements refer to young animals, makes no comment upon this measure-

ment. His specimen, if not young, is apparently very small for a Tamandua, its body-

length {without the tail) being only 37 cm. Dr. Sclater gives f the corresponding

measurement of a Tamandua which was in the Zoological Gardens as 20 inches (about

50 cm.). Rengger gives the length of a TamandiM which is still larger than Sclater's

specimen, being 22 inches (about 55 cm.) long %. Bu.t even admitting that Weber's

measurement refers to a young animal, the brain-weight which he records would be con-

sidered large even for an animal of the dimensions of Eengger's specimen. Por even then

the l)rain would be relatively larger than that of many Eodents of a corresponding size.

When we recall the fact that the brain of Tamandiia is not unlike that of a Rodent,

and may therefore be legitimately compared with it, we must admit that the brain of the

Ajit-eater is at least as highly developed as that of the Rodent.

We have unfortunately no record of the brain-weight in Cycloturus, although

Pouchet § assures us that the brain of this small Ant-eater (which he calls Dionyx) is

much lai'ger than that of Rodents and Insectivores || of a similar size.

Taking all tliese facts into consideration, Ave are safe in concluding that the Ant-eaters

are equijiped with brains which, so far as size is concerned, are certainly not inferior to

those of Rodents, and in all probability show a decided superiority.

According to Flechsig, the " centres of association " are as yet small in Carnivores,

while in Rodents they are entirely wanting. This statement may be interpreted to

mean that the insidious growth of association-elements within the pallium is not yet

sufficiently great in Rodents to make itself manifest, but that it has ncreased to such

an extent in Carnivores as to be recognizable beyond the limits of the areas of pro-

jection. It is in the highest degree probable that the distinction between the pallium in

MyrmecopJiaga and a Dog of a corresponding size is wholly due to the more abundant

development of association-elements in the Carnivore. For we have no reason to believe

that any of the sensory areas of the Ant-eater are to any marked degree less rich in

sensory elements than they are in the Dog. Nor are the primary end-stations, such as

the corpora geniculata, the corpora qnadrigemina, the tubercida acustica, or any other

of the masses of grey matter from which sensory tracts may arise and proceed to the

pallium, any smaller in the Ant-eater than they are in the Dog. In other words, so far

as we can judge, the pallium of the Ant-eater is as abundantly supplied with sensory

tracts as is the jJallium of the Dog, and therefore we are, I think, justified in concluding

* Max Weber, op. cit., Gegenbaur's Festschr. j). 7. t P. L. Sclater, Proc. ZooL Soc. London, 1871, p. 540.

X Eengger, ' Naturgeschichte der Saugethiere von Paraguay,' Basel, 1830, j). 309.

§ Pouchet, po. cit., tm. v. p. 664.

II He says Carnivores, but from the context there can be no doubt that he means Insectivores.

THE BKAIN IN THE EDENTATA. 383

that any excess in cortical area of the Dog over tlie Ant-eater nrnst be due to a richer

supply of iutrapallial elements, /. e. nerve-cells and tlieir resultant nerve-iibres which

associate the various sensory elements of the pallium the one with the other, as well as

with the cells whose axis-cylinder processes become projection-fibres and carry impulses

from the pallium to lower executive centres. In other words, the pallium of the Dog is

a more jjerfect machine thau tliat of the Ant-eater, in that it is more perfectly adjusted

to the higher psychical needs of the animal, and the actions of its various parts are better

co-ordinated by a richer association-system.

It is instructive to notice that the growth of the Dog's pallium has been a general

expansion and not a local hypertrophy ; in other words, the association-elements cannot

be regarded as forming areas, as we might suppose from a too hasty application of

Elechsig's ideas, but that they pervade the whole pallium, and with their increase there

is a general pallial expansion. At the same time we had occasion to observe before that

it is not unlikely that a localized expansion may have taken place in the area where we

find the crucial sulcus in the Dog. In this region the mechanism which controls the

movements of the limbs is being rapidly elaborated, so that the Carnivore can execute

those complex, almost skilled, and rapid movements ujjon which its livelihood is

dependent.

When we turn from the consideration of the Ant-eaters to the Sloths we at once

encounter some difficult problems. Por, while the pallium conforms to the Carnivore-

pattern in quite as marked a degree (at any rate in Bradypus) as it does in the Aitt-

eaters, it seems strange that in these small brains there should be so many sulci of such

a depth. Max Weber's tables contain a record of a Bradypiis tridactylus ? of 2130 gr.

weight with a brain weighing 16'5 gr. Thus this Sloth possesses a smaller brain thau

that of Tamandua, in spite of the fact that its body-weight is nearly double that of the

Ant-eater. And yet, while the pallium of the latter, as we have seen, is almost free from

sulci, the smaller pallium of the Three-toed Sloth is provided with a series of deep sulci

even more complete than those of the Great Ant-eater. The slightly larger brain of the

Two-toed Sloth has, in addition, a number of subsidiary sulci. It is quite possible that

the extreme shortness of the head in the Sloths may have the effect of limiting the

space for the brain, and that hence the expanding pallium becomes folded to adapt itself

to its limited space.

Erom a careful comparison of the brains of Tamandua and Gijcloturm (so far as this

has been possible) with those of Uodeuts, we must admit that the Ant-eaters are certainly

not inferior to the E-odents in the size of the pallium. Nor is the quality of the pallium

inferior, if we may judge of its richness by the volume of commissural fibres and

projection-fibres proceeding from it. In all that is of greatest signifieance as regards the

superiority of a mammal, the Ant-eater is at least the equal of the Hodent. And yet it

is customary to relegate the former to a much lower status than the latter. The evidence

of the brain in the Great Ant-eater shows that this animal is not far removed from

the Carnivora, and the whole tendency of our examination of this group is to bring them

into very close relationship with such typical Eutheria as the Eodents and Carnivores.

52*

384 DE. G. ELLIOT SMITH ON

In Tamandna, as a resvilt of the elongated form of the head necessary for an Ant-eater,

the brain has plenty of room to expand, and hence its cortex does not become folded

like that of the Slotlis.

If it be true that the surface of the pallium of Bradijims thus becomes folded in

accordance with mechanical principles, it is somewhat remarkable that the arrangement

of its sulci should follow a plan whicli is obyionsly the expression of an inherited tendency.

That this does take place there can be no doubt, for when we examine a large series of

mammalian brains we are surprised to iind in organs of the most variable shapes con-

vincing evidence that the arrangement of the sulci has been determined by some principle

other than the purely mechanical factor which may have been the exciting cause of

their development.

Max Weber records a brain weighing 11-3 gr. in a DasyptLs sexcinchis c? of 2567 gr.

There is a most decided fall both in tlie absolute and relative size of this brain wdien

compared with those of tlie Sloths and Ant-eaters. Nor does a comparison of this record

with those of members of the Rodentia, Chiroptera, or even Marsupialia, serve to

brighten or place in a better light the degradation of the Armadillo. Por in the

Marsupial Trichosuriis we find the record of a brain of the same size as that of Dasjjpus

in an animal of merely 1724 gr. But at the same time it is only right to add that a

Didelphys of BiSO gr. has a brain of merely 6"5 gr.

I think there is ample reason for hesitation before consigning the Armadillos to a

lowly place, even if we admit, as is not improbable, that this single record is typical of

the family.

In our consideration of the factors which may modify the size of the pallium we have

already pointed out that the decadence or diminished acuteness of any sense-organ may

exercise a marked effect upon the size of the pallium in those mammals in which the

" areas of association " are not yet definitely established. In the consideration of the

mesencephalon we have already had evidence to demonstrate that the visual acuteness of the

Armadillos is on the wane. When we consider how large a share visual representation

must take in the primitive pallium, we must admit that this is a potent factor in modifying

its size. In addition to this, it is hardly to be believed that tactile impressions are of much

importance, or find any scope for their exercise, in an animal encased in armour. The

tendency of recent research is to recognize in the optic thalamus a station wiiere not

only the visual but also the general tactile path receives a relay on its way to the

pallium. If this be so, w^e may perhaps be able to understand why the optic thalamus

is reduced to such exceedingly diminutive proportions in the Armadillos. If we admit

that the visual and tactile senses have a diminished importance in the Armadillos, I

think that there is in this fact an ample reason for the diminutive size of the pallium.

Pouchet tells us that the brain of Chlamydo'phorus is much larger than that of the Mole

( TuIjm). If this be a fact, it may be of value as evidence of the superiority of the

Ai-madillo over the Insectivore.

We must regard the i\rmadillos as the descendants of mammals with a higher degree

of visual and tactile acuteness, and a much more extensive pallial representation of these

senses than they at present possess.

THE BRAIN I\ THE EDENTATA. 385

It is strange that in animals with such a small and insignificant pallium, which is not

of sufficient extent to produce a complete rhinal fissure, we should find representatives of

what we must regard as the supraorbital (/3) and sometimes also the suprasylvian (S)

sulcus. So far as we are at present capable of judging with our limited knowledge of

the factors of pallial growth, there is little, if any, mechanical demand for any such sulci.

If this be so, these fissures must have been inherited from ancestors of the Armadillos

which possessed a more extensive pallium with fully-formed supraorbital and supra-

sylvian sulci.

The evidence of anatomy and palaeontology, which has been carefully summed up

by Sir William Flower*, clearly points to the undoubted kinship of the Ant-eaters,

Sloths, and Armadillos. There is nothing in the evidence of the brain which does not

thoroughly harmonize with this view. Ilyrmecophafja exhibits a close resemblance

to the brain of the Carnivora which we have already examined in detail. When we take

into consideration the multiplicity of factors which are moulding the pallium into such

varied forms in different groups of mammals, it is difficult to explain the resemblance

between the pallial configuration of the Great Ant-eater and that which prevails in the

great group of Unguiculata, as other than the expression of a genetic relationship, and

not of fortuitous similarity.

We equally find in Bracli/pt(s, but to a less marked degree in Choloepus, signs of

conformity to the Carnivore type of brain.

In the case of the Dasypodldce, the rudimentary sulci /3 and o may be the remains of

a similar pattern, but it is so fragmentary that from the evidence of the brain alone we

could not definitely locate these peculiar animals.

In spite of the obvious differences which exist between the brain of the Carnivora and

that of the Ungulata, we find that among their most constant mori^hological features

there is a very considerable anaount of agreement, while other constant features coexist

to point the contrast. The arrangement of the supraorbital and sagittal sulci, and

to some extent the splenial sulcus, is so obviously homologous in the two types that we

cannot regard this fact in any other light than the expression of an ultimate genetic

relationship. If we trace the ancestry of the Ungulata and the Unguiculata back, we

ultimately reach, according to the evidence of recent palaeontology, a common Creodont

stock, from which at the dawn of the Eocene the Condylarthrous progenitors of the

modern Ungulata diverged from the forerunners of the Carnivora t- It is highly probable

that in the simj^le brains of these primitive Creodonta those tendencies of growth

were already impressed which equally manifest themselves in the pallium of the two

diverging groups which spring from this common stock.

The divergence of these two stocks is manifested in the contrast between other

features of the pallium in the two groups. The pallium in the Carnivore at a very early

epoch bulges downward posteriorly, while this tendency is wanting in the Ungulata.

* W. H. Flower, " On the ilutual Affiuities of the Animals composing the Order Edentata," Proe. Zool. Soc.

London, I881!, pp. 358-367.

t W. D. Matthew, " A Revision of the Puerco Fauna," Bulletin of the American Museum of Natural History,

vol. is. 1897, p. 293, Condylarthni .

386 Dli. G. ELLIOT SMITH ON

The effect of this is that iu the Carnivore there is an early and most pronounced

tendency in the suprasylvian sukius to assume an arcuate form, whereas in the Ungu-

late the correhpondiny fissure is horizontal uutii, in a late stage in certain Ungulates, the

perfection of the Sylvian fissure produces a secondary arching in the suprasylvian

fissure. There is also, as we have already had occasion to remark, a correlative change

in the early Carnivore and early Ungulate type of Sylvian fissure.

Among certain mammals, such as the Rodents, there is an ill-defined tendency toward

a development along the Carnivore line of evolution, but it is never very pronounced.

At tlie same time we find in some Rodents, as for instance Lepus, a decided caudal

dovvngrowth of the pallium which is not unlike the condition in Tamandua. Among

other Rodents * we find evidences of a sagittal sulcus, a supraorbital, and occasionally a

fossa Sylcil, which in a vague manner suggest a tendency similar to that exhibited in

the Carnivore's brain. The Chiroptera present a type of brain similar to the Rodentia

with even fewer indications of their affinities, and they both gradually merge into

the generalized type of the Insectivora, which gives no indication of the peculiar

specializations of the higher groups. When we consider that the Carnivore type is so

distinctly marked ofl' Irom that of all other groups of mammals, and find in an

enigmatical lamily of mammals such as the Ant-eaters an exact reproduction of all

the salient features of this distinct type f, we are justified, I think, in attaching some

taxonomic value to the resemblance.

If we admit that such a genetic relationship does exist, we must make the further

concession that the Aut-eater stock branched oh' in all probability from the early Ungui-

culate stock at a period subsequent to the splitting off of the Condylarthra or primitive

Ungulata. Although the brain of the Ant-eater is far inferior to that of the Carnivore,

it is immeasurably superior to tliat of the primitive Creodont. Arguing from the

evidence afi'urded by the brain, we might surmise that the Ant-eaters branched ofi* at

an early epoch from the primitive Carnivore stock at a time when the peculiar and

distinctive tendencies of pallial development had been fully determined. But Avhile

the- Carnivores, leading an open life of free competition, have in the keen struggle for

existence developed iu a high degree the organ which permits them to successfully

maintain the struggle, the Ant-eaters, on the other hand, have become peculiarly

specialized to a particular kind of life in which their safety is assui-ed, not by an exercise

of a highly developed brain, but by leading a life of seclusion. They pursue a prey which

does not call for that exercise of cunning and keen activity of muscle which alone can

make a Carnivore's life possible.

According to the interesting palseontological investigations of Wortmau 1, the early

Eocene deposits of North America contain a series of peculiar extinct mammals,

Ijeginning from the earliest Puerco and continuing uninterruptedly into the Bridger,

which seeju to throw an interesting light upon the ancestry of the American Edentates.

* Cf. F. E. Beddard, Proc. Zool. Soc. London, 1S92, p. 596.

t Except for the crucial sulcus, -which we have discussed elsewhere.

+ J. L. "Wortmau, " The Gauodouta aud their Eelatiouship to the Edentata," Bulletin of the American Museum

of Natural History, vol. is. art. vi. pp. 50-110, 1897.

THE BEAIN IN THE EDENTATA. 387

According to this writer, tliese peculiar mammals, which lie calls Ganodoida *, show a

series of modifications which indicate tlie change from a typical mammal to a highly

specialized form which is practically identical with the Edentate type. He concludes

that the South- American Edentates of the present day sj)rang from this Ganodont stoci^,

which began with Hemigamis and lead up to Styliuodon, and at the beginning of the

Santa Cruz epoch they wandered from the Northern to the Southern continent. The

distinctions between the members of this Ganodont stock and the Creodonta and Tillo-

dontia are so slight, that we find different members of Wortman's group variously

included in the Creodonta and Tillodontia by Cope, Marsh, and von Zittel, among other

palaeontologists.

It is not for me to express an opinion either for or against the evidence of a Ganodont

origin for the Edentata ; but this brief review of the recent tendencies of American

palaeontology makes it clear that in suggesting, upon the evidence of the data collected

in this memoir, an origin of the Ant-caters from some post-Creodont stock which has

since then diverged from the Unguiculate stem, we are not contradicting palseonto-

logical evidence, but that, on the contrary, we are to a very considerable extent supported

in our contention by this.

This leads lis to the consideration of the position of Ori/cteropus. If the brain of

Orycteropus were given to an anatomist acquainted with all the other variations of

the mammalian type of brain, there is probably only one feature which would lead

him to hesitate in describing it as an exceedingly simple Ungulate brain. That one

feature is the high degree of macrosmatism. But we know how readily the degree

of macrosmatism vai'ies with the change of habit of the animal. Within the family of

Ant-eaters we have seen the terrestrial Myrmecopliaga exhibiting a high degree of

macrosmatism, and the arboreal Cyeloturus showing an equally noteworthy reduction in

the size of its rhinencephalon. We may therefore associate the high degree of macros-

matism of Orycteropus with its peculiar mode of life, and regard it as a functional

modification of little taxonomic value. Such being the case, the similarity of the brain

to that of the macrosmatic IIoscJius is of exceptional interest, when we remember that

the latter mammal retains " characters belonging to the older and more generalized

types of ruminants " f and is a relative of the primitive hornless deer of the lower

Miocene +. The characters of the brain of the Aard-vai'k which lead us to associate it

with the Ungulate type are the horizontal direction of the whole rhinal fissure {i. e. the

absence of a downgrowth of the pallium) and the horizontal arrangement of the repre-

sentative of the suprasylvian sulcus. The features of the region where we find the

fossa Sylvii in Myrmecophaga, and its similarity to the peculiar arrangement of the

Sylvian fossa in Mosclms moschjfems §, add further testiiuony to this Ungulate likeness.

At the same time we must admit that it is far inferior to existing Ungulates in regard

* J. L. Wortman, " Psittacotherium, a Member of a New and Primitive Suborder of the Edentata,'' Bull. Amer.

Mus. Nat. Hist. vol. viii. art. xvi. 1896.

t Flower and L)-dekker, 'Mammals, Living and Extinct,' 1891, p. 314.

t A. S. Woodward, ' Tertebrato Palaeontology,' Cambridge, 1898, p. 365.

§ W. H. Flower, Proc. Zool. Soc. London, 1875, p. 175.

388 Dli- &• ELLIOT SMITH ON

to its pallial development, a fact wliicli miglit be explained in. the manner I have

attempted to explain the shortcomings of Myrmecophaga when contrasted with the

Carnivora. In the subsequent development of the post-Oreodont mammals we find

increasing complication and specialization of various anatomical systems, in corre-

spondence with the varying conditions of life. This is seen in the jaws and other parts

of the skull, in the structure of the limbs, in the modifications of the alimentary tract,

but progress is especially noticeable in the brain. In all the existing descendants of the

Creodont stock the brain has increased enormously in size, but in some groups to a much

greater extent than in others.

In an interesting memoir, Max Weber has discussed the peculiar contrast between

the size of the brain in the Hippopotamus and the Elephant *. In two animals of

approximately the same weight, one (the Hippopotamus) has a brain of 582 gr., while the

other (the Elephant) has a brain of the enormous weight of 3370 gr. Max Weber says

that the former reminds us of the Tertiary mammals, which Marsh has shown to have

remarkably small brains, and he expresses the opinion (p. 6) that an animal with such a

relatively small brain could have held its own in the struggle for existence only by its

safe mode of life. It is of some significance in this connection that the Hippopotamus

shows in other parts of its anatomy indications of a very primitive type f. It seems not

improbable that in the case of the Hippopotamus and also of OnjcteropmX we have

two "lonely creatures" who have become specialized, but only slightly removed from

the primitive parent stock. They have early taken to eminently safe modes of life, and,

by avoiding the fierce struggle for existence which "weeds out" most mammals that

fail to keep pace with the rapid pallial growth, they have managed to linger on in spite

of their inferior pallial equipment. The marvel is not that there should remain only

solitary examples of these forms, but that even these few representatives of such stujjid

creatiu-es should have escaped the fate of the imbecile Glyptodou.

To the student of brain-anatomy the name which the Du.tchmen of the Cape have

o-iven to Orycteropus may not seem so singularly inapproj)riate as it is generally supposed

to be ; for in this simple and archaic " Earth- Pig " he may find an exceedingly early

offshoot from the root-stock of the Ungulata or Condylarthra.

In Pouchet's memoir, to which we have so often referred, a doubt is expressed as to

whether MaGrotherimn should not be included in the family of Aard-varks. Most

observers, however, suggested an analogy between Ilanis and Macrothcrimn, until it was

shown that the latter possessed vertebrae and teeth such as we find in a Perissodactyle

TJno'ulate §. But to this Oldfield Thomas adds : — " One could not dare to suggest that the

ancestors of J/«/m'5 or Orycteropus were to be sought in that direction" 1]. It would

unquestionably be absurd to look for the ancestor of Orycteropus among the Perisso-

* Max "Weber, " Over bet Eeiseugewigt dcr Zoogdieren," Koninklijke Akademie van Wetenschapioen te

Amsterdam, October 1S96. t A. S. Woodward, ' Vertebrate Palaeontology,' p. 346.

j M'. K. Parker, 'Mammalian Descent,' p. 97, wrote : " If ever tbere was a generalized type, tbis [the Aard-varkl

is one."

6 II. F. Osborn, • American Naturalist,' 1882, p. 728.

11 0. Tbomas, op. cii., Proc. Eoyal Soc. vol. sh-ii. (1890) p. 248.

THE BRAIN IN THE EDENTATA. SS^

dactyla ; but in view of its cerebral features vre are justified in looking for its ancestry in

tlie early Eocene Ungulate stem, long after tlie Carnivore stock from whicli the American

Edentata are probably derived bad branched off from the Crcodonta, which the American

palaeontologists regard as the common progenitors of all these diversely specialized

animals. Such a view does not necessarily conflict with the opinion of Kitchen Parker,

who, in knowledge of many resemblances between the skulls of Orycteropus and Wiyncho-

cyon, suggested that the former may be an off'shoot from the Insectivorous stock *. From

the generalized structure of Orycteropus and the simplicity of its brain, we may infer

that it has not advanced far beyond the stage of the jirimitive Creodonta, which are

nearly related to the Insectivora primitiva, while all its near relatives have either been

vastly changed in body, limb, and brain to meet the fierce competition by specialization

of form and improvement of cerebral structure or have succumbed in the struggle and

become extinct.

The evidence for this distant kinship wdth the primitive Ungulates is not absolutely

conclusive, but it clearly demonstrates the distinctness of the Aard-vark from the

Ant-eater, and suggests the relationship indicated in the foregoing paragraphs. In a

memoir to which I have already referred, Oldfield Thomas remarks that " we are wholly

in the dark as to what other mammals " Oryctero2ms " may be allied to " (p. 248). Under

such circumstances it is important to place on record even such indecisive straws of

evidence as I have herein supplied, as denoting which way the tide of evolution

may have flowed in bringing down to the present generation this pecuHar waif of a

past age.

The brain of Uanis is in many ways peciiliar. Max Weber gives three records of

the brain-weight wdiich are singularly discordant : —

Manis javanica, $ , body-weight 1750 gr.^ braiu-weigbt 9'5 gr.

„ ?, „ 3500 gr., „ 11 gr.

8000 gr., „ ISgr.t

Unless these weights refer to animals of different ages we are at a loss to explain

the extreme variations of the body-weight. Dubois says % that the immense superiority

in the brain-weight of Myrmecoplmga over that of ILanis is " a new reason for

separating the American Edentates from those of the Old World." It seems to me

that this is quite a fallacious argument. Among the American Edentates themselves,

we find in the three families extreme variations in brain-weight, and in a natural group

like the Hodentia we find contrasts § quite as marked as that which exists between the

Great Ant-eater and the Pangolin \. If we are going to separate these two animals

we must find some more genuine distinction than that which Dubois suggests.

* W. K. Parker, " On the Structure and Development of the Skull in the ITammalia. — Part. II. Edentata."

Proc. Royal Soc. London, vol. xxxvii. p. 80.

t This weight we owe to Kohlbrligge, Natuurkdg. Tijdschr. Ned.-Indie, Iv.

i Eugene Dubois, " Poids de I'Encephale chez les Mammiferes," Bulletins de la Societc d'Anthropologie de Paris,

t. viii. iv'' serie (1897) p. 374.

§ Dubois himself has noticed this fact in tl.e Rodents, op. cit. p. 373.

II Vide Max Weber's tables, op. cit., Gegenbaur's Festschrift.

SECOND SERIES. — ZOOLOGY, VOL. VII. 53

390 DE. Q. ELLIOT SMITH ON

Considering the small size of tlie brain in Manis, the most impressive feature is the

presence of so many pallial sulci. The reason for this may possibly be the resistance

which the smallness of the cranial cavity offers to the expanding brain. The small size

of the pallium in this peculiar animal is not necessarily a sign of its extreme inferiority,

as Dubois seems to sujjpose. It may to a great extent be explained by tlie fact that the

animal is encased in scales, since, if our introductory argviments are sound, the tactile

element in the pallium may thus reasonably be supposed to be greatly reduced.

From a consideration of the cerebral features, it is difficult to add anything of a

4ecisive nature to tlie enigmatical evidence of the other parts of the body. The con-

figuration of the pallium exhibits in a well-defined form the distinctive features of all

the progeny of tbe Creodonta, but it is very difficult to say whether it favours the

Ungulate rather than the Unguiculate stem or vice versa. The fact that the supra-

sylvian sulcus has a distinct tendency to an arcuate form may at first sight seem to

point distinctly to a kinship with the Carnivore or i^.merican Edentate group, but it is

not unlikely that the obvious limitation of growth in the longitudinal direction may

account for this peculiarity. Then, again, the resemblance which the complex of the

posterior rhinal fissure and the supraorbital and sagittal sulci bears to the corresponding

feature in Oryctet'opus may point towards an affinity in this direction.

In considering the American Edentates, we have already learned that there was no

feature or combination of features in the brain of the Armadillos which would lead us

to associate them with the other American forms, if we had no knowledge of the other

parts of the body, and especially the peculiarities of the spinal column. In such a

simple type of brain as that of the Armadillos, which presents the typical Eutherian

features, there is little of taxonomic significance. In the large brain of Priodon we

should in all probability find some definite evidence, but while the other members of the

family exhibit no cerebral features in opposition, they give no positive indication of the

Adew, which the characters of the vertebral column seem to conclusively prove, that a

o-enetic relationship certainly exists between the three American families.

The case of the evidence afforded by the brain in the Pangolins is exactly similar.

For while it shows that the brain of Manis conforms to a simple type of architecture

which agrees in many points with those of both Orycteropus and the American Edentates,

there is not sufficient evidence to show decisively which type it really favours. When

we consider how markedly the Pangolin differs from both the other groups in the anatomy

of the other parts of its system, I think that we are fully justified in following Max

Weber's suggestion * of dividing the group Edentata into three orders : —

Order Xenarthua (Gill).

Family 1. Bradypodidcp.

2. Myrmecophagida'.

3. Dasypodida.

* Max Weber, ' Zoologisclie Ergelanisse,' ii. p. 110.

THE J5EAIN IX THE EDENTATA. . 391

Order Tubultdentata.

Family ] . Onjctcropodid(B.

Order Squamata.

Family 1. Manidce.

Some confusion may arise from the use of tlie name Sq^mmata, which is also applied

to lizards and snakes.

The question which naturally arises in the consideration of sucli a division into orders,

is whether the gain in pedantic accuracy is a sufficient justification for disturbing a well-

known group, which everyone miist now recognize as a mere conventional assemblage

with no genuine bonds of union, and th\;s adding to the number of orders. The view

which Oldfield Thomas takes concerning Oryeteropus — that "it has been placed there

[along with the American Edentates] rather on account of the inconvenience of

forming a special order for its recejition than because of any real relationship to them " * — ■

is endorsed by Flower and many other competent authorities. If Orycteropus is more

nearly related to jllanis than either is to the Xenarthra, as is not at all improbable,

we must at present confess that we liave no evidence to warrant such a contention.

Such being the case, the adoption of the Nomarthra does not apj)ear to me to help

toward a clearer conception of tbis undoubtedly heterogeneous collection of mammals.

It seems possible to adopt a compromise wbicb will avoid the disruption which

Thomas dreads, as well as the anomalous course of including within one order animals

which have nothing in common except certain functional modifications which are

obviously adaptations to the pecu.liar mode of life.

In the light of our present knowledge, the group undoiibtedly ought to be divided

into three orders, as Mas Weber suggests. But the meaning of the name "Edentata "

is so well appreciated that it is not likely to fall into disuse, however much we might

wish for such a consummation. The frank recognition of this fact may save us from the

disturbing influence of new orders, if we retain the name " Edentata " on the distinct

understanding that it consists of a heterogeneous " group " of three " orders," which

have no necessary relationship the one to the other.

The three existing families of Xenarthra are much more widely separated one from

another than is usual among mere " families," for they possess very little in common.

The application of the term " suborder " to these three groups might express the

distant relationship more effectively if it were not for the fact that, in view of the

existence of only one family in each suborder, the additional names would merely add

to the confusion t. On the whole it is desirable to adopt Max Weber's suggested

* Oldfield Thomas, Proo. Eoy. Soc. vol. slvii. (1890) p. 248.

t I have not discussed in this place the very marked distinctions, especially as far as the cerebral commissures

are concerned, which separate the three families of Xeaarthra. They have been sufficiently indicated in the body

of this memoir. I may, however, remark that the apparent simplicity of the commissures in the Sloths is not

necessarily an indication of a primitive condition, but may be merely a reversion to the archaic condition such as

I have found in the Bat Nyctopliihis (" The Origin of the Corpus, Callosum," this Vol., p. 47).

392 DE. G. ELLIOT SMITH ON

division into orders and retain the term Edentata as a convenient if unnatural

expression.

The labours of palaeontologists have been amply rewarded within recent years,

especially in North America, by excejitionally rich finds of extinct mammalian forms

which enable us to trace the genealogy of many of the great groups which have

survived until the present clay. In the light of the knowledge gahied from these records,

we can trace the ancestry of the carnivorous clawed mammals (Unguicuiata) and of the

herbivorous hoofed mammals (Ungulata) back to generalized forerunners, which at

the beginning of the Eocene period are with difficulty distinguishable the one from the

other.

Not only is this so, but many of the contemporaries of these generalized forms which

inhabited the earth at the beginning of the Tertiary epoch are equally difficult to dis-

tinguish from these ancestors of the Carnivores and Ungulates. At this time we find a

huge multitude of primitive mammals — Creodonta, Condylarthra, Amblyopoda, Gano-

donta, Tillodontia, among others, — and so generalized are all these forms, that it is not an

easy matter to decide in the case of any whether we are dealing with the ancestor of

the Primate, the Carnivore, the Ungulate, the Edentate, the Rodent, the Insectivore,

or even the Marsupial.

One of the most noteworthy features which all these generalized and primitive

mammals possess in common is the exceedingly small size of the brain. Eor at this

epoch the pallium had just made its first appearance, and the cerebellum was yet in a very

primitive condition. When we compare the diversely specialized forms which are rapidly

evolved fiom this simple generalized type as the brain increases in size, we are able to

appreciate how immense an impetus the forces of evolution received when a pallium

first made its appearance in the brain of the Saurian ancestor of the Mammalia.

The profound effects of this important event almost immediately begin to manifest

themselves in the body generally, and become recorded for all time in the modifications

of the limbs which fossil forms present. Eor as complex muscular acts were rendered

possible by the development of the pallium, the skeleton became modified in adaptation

to these acts. The skeleton thus began " to assume characters and potentialities such

as it had not exhibited before, and an entu-ely new set of modifications " became

possible *.

Under the potent influence of these new factors, which are so favourable to a rapid

adaptation to any circumstances in which the individual may happen to be placed, the

early mammal soon became specialized to various modes of fife, and developed new

forms of modifications with aU the exuberance of its newly-discovered potentiality to

excel. The effects of these modifications are most clearly demonstrated in the limbs

and in the teeth, and, most important of all, in the brain.

In the keen struggle for existence, the mammal best equipped with a highly-developed

brain, which endows its possessor with the cunning and nimbleness which are of more

value than all the protective modifications, whether offensive or purely defensive, must

prevail. In the increasing competition among mammals, the], progressive perfection

* A. S. Woodward, ' Yerlobrate Pala-ontology,' p. 246.

THE BRAIN IN THE EDENTATA. 393

of the brain becomes a necessity if the individual is to siu'vive. But after the brain has

attained to a certain degree of development, and competition becomes keener, endless

varieties of special modifications take place in different mammals in adaptation to special

kinds of life. Tliose animals whose brains do not keep pace with the general advancement

of the Class must either drop out of the race or adopt some special protective mechanism

or habit of life which may save them from extinction. The Insectivora, which are the

specialized remnants of one of the lowliest stages of mammalian development, are examples

of this. The more generalized mammals continvie their onward progress in virtue of their

cerebral superiority, but from time to time groups branch off and, forsaking the fierce

race for pallial supremacy, adojit habits of life and corresponding bodily modifications

which will enable them to maintain the struggle against those of their relatives whose

better brain-endowment enables them to endure without any marked bodily specialization

for self-defence. But the individual which devotes all its energies to self-defence at the

expense of its brain is bound before long to share the fate of tlie GUjptodon, even though

it be " built like Eome," as the late W. K. Parker remarked.

The last descendants of tbe main generalized stem which never turned aside to

adopt protective modifications or specialized habits of life, but prevailed in virtue of

their brain-superiority, became the Primates. They have attained the loftiest position in

the mammalian series, and at the same time retained much of the simplicity of the

generalized type from which they sprang. It seems as though the adoption of specializa-

tions of an offensive or defensive nature is a confession of weakness.

The Ungulate lagged behind in the race for supremacy in cerebral organization at an

early period, and by fleetness of limb and largeness of body has sought to compensate for

its inferiority of brain. But in spite of this fact it still leads an open life, and the

progressive development of its brain is still of vital importance. Hence we find that

in the various offshoots fi'om the primitive Condylartlira the growth and elaboration

of the brain become conditions of survival. In all probability Orycteropus became

specialized from the generalized type at about the same time as the Ungulata, and it

is not improbable that it may even have branched off from the primitive Ungulate stock.

The generalized type of its body and limbs shows that it must have adopted its pro-

tective habits of life at this period, and the configiu'ation of its brain indicates that it

may for some time have followed the Ungulate line of development. Innumerable

modifications of the generalized type branched off at the same time as the ancestors of

the Ungulata, and, either from lack of the capacity to develop their brain or to adopt

some manner of protection, they succumbed in the struggle and became extinct. Of

the few types which svirvived this process of extinction, Ilanis is probably an

example. Although its brain has reached a very considerable degree of development,

it has survived by virtue of its peculiar protective mechanism and of its naode of life.

Soon after the branching-off of the Ungulata, it is probable that the Rodentia became

specialized as a distinct group. They may have arisen from tlie common stem from which

also the Carnivora and probably the Xenarthra sprang, but if so they branched off

from this stem before the close of the Eocene, and by adopting a safe mode of life and

SECOND SERIES. — ZOOLOGY, VOL. VII. 54

394 ON THE BRAIN IN THE EDENTATA.

generally a small size of body, they were able to survive without that high degree of

brain-development which became a vital necessity to the Ungulate, the Carnivore, and

especially the Primate.

It is not improbable that the Xenarthra are more nearly related to the primitive

Camivora of the Eocene epoch than are the Rodents. Otherwise it is difficult to under-

stand the features of the brain of Myrmecophaga. But if this is so, the Xenarthrotis

stem branched off from the Carnivore stock at an early epoch, and almost immediately

it widely diverged into a number of distinct branches. The Armadillos separated them-

selves from the others at a very early period, and underwent extreme bodily modifications

of a protective nature in order that they might be able to escape extinction, because their

brains had become reduced to the lowly standard of the Insectivora.

The Sloths and Ant-eaters also diverged soon afterwards, and, althovigh their brains are

of no mean order, they would not be able to exist if it were not for the safe modes of

life which they lead, and the peculiar specializations of limb and body which so admirably

fit them for such habits.

"We may conclude that the evidence of the brain clearly demonstrates that the

Edentata are much more nearly related to the ordinary placental mammals than is

commonly supposed to be the case. Not only so, but the brain has also reached a fairly

high stage of development in all the rejiresentatives of this extremely heterogeneous

group, and may certainly be placed upon a plane at least as high as that of the Rodentia.

The features of the brain conclusively show that Orycteropus is no more nearly related

to the American forms than the Sheep is to the Dog.

The gradual loss of teeth, and the associated modifications of skull and limbs, do not

necessarily imply a retrograde or degenerative process so much as extreme specialization

and adaptation to particular modes of life.

LINNEAN SOCIETY OF LONDON.

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211(1 Ser. ZOOLOGY.

LVOL. VII. PART 8.

668! 'oS 9nv

THE

^&/

''h

TRANSACTIONS

OP

THE LINNEAN SOCIETY OE LONDON.

AMPHIPODA FROM THE COPENHAGEN MIJSEUM AND OTHER SOURCES.

Part IT.

BY

The Rev. THOMAS R. R. STEBBING, M.A., F.R.S., F.L.S.

LONDON:

PRINTED FOR THE LINNEAN SOCIETY

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SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE, PICCADILLY. W.,

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[ 395 ]

AUG 29 i«9^

VIII. Amphipoda, from the CopenJiagcJi Muscjnn and other Sources. — Part II.

By the Heo. Thomas R. R. Stebbing, M.A., F.B.S., F.L.S.

(Plates 30-35.)

Read 3rd November, 1898.

Introdtjctory Remarks.

JN O panegyrist of the Amphipoda has yet been able to evoke anything like popular

enthusiasmi in their favour. To the generality of observers they are only not repellent

because the glance which falls upon them is unarrested, ignores them, is unconscious of

their presence. The majority of the species keep themselves effectively concealed from

all but pertinacious intruders, beneath stones and weeds and varying depths of water.

Of the families to be dealt with in these pages the first is the Orchestiidae, or, as some

might prefer to call it from the genus fii'st described, the Talitridae. This is of all the

Amphipoda the family whicli has made the strongest eff'ort to place itself in evidence

and to overcome the disregard of a neglectful world. More than any of the tribe it has

invaded the land, so that its representatives may be found, not only in the sand-hillocks

above high-water mark, but in gardens, in woods far from the sea, on hills, in ci'aters of

extinct volcanoes. It has climbed higher than any of the Crustacea excejit a few wood-

lice, some of the freshwater forms having been taken by Mr. Whymper at a height of

more than thirteen thousand feet in the Gi-eat Andes. Another mark of distinction may

be found in the excessive trouble which nature and art have enabled it to give to the

systematist. Not only are the descriptions and figures bequeathed to us by eminent

naturalists and artists full of puzzles, but the creatures themselves have conspired in

various ways to make the path of knowledge thorny and fatiguing.

Genera, the S2:»ecies of which have different habits, and which are separated by the

unlikeness of the males, are in the females scarcely distinguishable (Talitrus and

Orchestia). Genei'a which have been put apart by a decisive character provokingly

join hands just when their separation is most needed. A great increase in the number

of known species brings to light the missing links, which, as every one knows, are the

curse of classification [Orchestia and Talorchestia).

Characters which at one time distinguished large groups, or were valid for the Avhole

family, are gradually nibbled away by exceptions here and exceptions there till all the

neatness and comj)leteness of the arrangement they provided are muddled away and

spoiled. Por example, it can no longer be stated with precision that the Orchestiidae

always have the first antennae shorter than the second, and the third uropods with never

more than a single branch. It is safer to say in the one case almost always and in the

SECOND SERIES. — ZOOLOGY, VOL. VII. 55

396 KEY. T. E. E. iSTEBBING ON AMPHIPODA FROM

other hardly ever. The clear division of the family into two groups hy the palp of the

maxillipeds is brought to nought. It is still true that there are some of the genera in

Avhich the joints of tlie palp in question are four, and others in which they are only

three, but forms are uoav known in which they are not properly either three or four, but

rather three and a fraction {ParorcliesUa).

The anomalous family of the Phliadidai, with which this paper is next concerned, was

introduced to scientific notice by that great pioneer in the zoology of the coast-line,

Colonel Montagu. It was probably at Salcouibe, in South Devon, that he found the

typical species. To this he gave the name of Oniseus testado, indicating by the generic

name that he made the cot unnatural mistake of supposing it to be an isopod. Some of

its since found congeners have an even more striking likeness to some of the Isopoda.

All the Serolidfe are broad and flat, but in them the tortoise-like and chiton-like appear-

ance is generally impaired by projecting appendages. On the other hand, a New Zealand

isopod genus, Plakarthrium Chilton, subsequently again described from South Georgia

by Pfefler under the name Chelonidium, has a iacies with which that of some of the

Phliadidai is exactly comparable. Montagu's species has been found in the Medi-

terranean, and now a first cousin of it comes to us from Australia. Prom Australia and

New^ Zealand together avc ore supplied, as will be sho\\u, Avith four species of this family

so remarkably alike in general appearance and in many conspicuous details of structure

that one might readily take them for conspecific varieties. Minuter study brings to

Ii<'-ht the curious circumstance that thev are not only specitically distinct, but that thev

are separated one from another by characters of generic value.

After one or two notes on the family Melphidippidse, the paper concludes with the

definitions of several new genera within the family of the Gammarida?. The genus

Gmmnarus may be regarded as antediluvian, because, since its institution by Fabricius

in 1775, a whole flood of genera has issued from it. With successive restrictions it still

remained unwieldy. The researches of DyboAvsky in Lake Baikal added a hundred and

fifteen species within the compass of a single treatise. Some of the Lake Baikal forms

differ so strikingly that it requires either a very lax or a very lofty standard of generic

value to allow the comprehension of their varied charactei-istics within a single genus.

It is useless to apologize for the institution of new genera. Their fate not uncommonly

is at first to be abused as needless, inconvenient, and ill-constructed. Attempts are

sometimes made to ignore them and set them aside. Then, as time goes on, they are

found to be necessary, they are recognized, and pass into circulation as current coin of

the scientific realm.

The redistribution of species of Gammaridai here offered would more naturally, as it

seems to me, have appeared in that general account of the Amphipoda which is being-

prepared for ' Das Tierreich.' But the organizers of that vast scheme of zoological

publication have passed a self-denying ordinance. Novelty is excluded. There are to

be no surprises. The contributor is not to expand the sum of knowledge, but to con-

dense it. Prom one point of view this is a Avise and considerate arrangement, but it has

a drawback. In surveying any large group of the animal kingdom, especially among

THE COPENHAGEN MUSEUM AND OTHER SOURCES. 397

invertebrates, a reporter can scarcely pursue his studies very far without finding that

there arc new forms to be described, new names to be applied, new items of classification

to be introduced. For all these the rule above mentioned requires double publication,

and this, unlike the quality of mercy, wdiich blesses him that gives and him that takes,

is an almost unmitigated nuisance to the writer and the reader.

It now remains for me to express my hearty thanks to Dr. Meinert and his colleagues

at the Copenhagen Museum, and especially to Dr. H. J. Hansen, for entrusting me with

the fine collection of Orchestiidii? under their charge. To the Trustees of the Australian

Museum, Sydney, I am indebted for ' co-types ' of some of Professor Haswell's species sent

me through the obliging intervention of Mr. R. Etheridge and Mr. Thomas Whitelegge.

From America specimens of great service to my work have been sent me by Mr. James

Benedict, of the National Museum, Washington ; by Mr. S. J. Holmes, of the University

of California ; and by Mr. C. F. Baker, of the Alabama Polytechnic Institu.te. To

Professor Mobius I owe my thanks for examples of several of the Lake Baikal Gammarids.

Mediterranean specimens received from my friends M. Ed. Chevreux and Signor Delia

Valle have thrown light on various obscure parts of the subject. Lastly, I must refei"

to the special kindness of Professor HaswcU, F.E.S., and Mr. Thomas Whitelegge, who

have sent me miscellaneous gatherings of Australian Amphipoda, enabling me to

dredge for southern rarities under the shelter of my own I'oof in the peaceful shallows of

a watch-irlass.

Fam. OECHESTIIDaE.

Sijnopfic Tleic of the Genera.

, f ^laxillipeds, fourth joint of palp wanting or quite rudimentaiy, 3.

y Maxillipcds, fonrtli joint oi^ palp distinct, o.

First gnathopods simple in the male, 3.

First gnatliojiods snbehelate in tlie male, 4.

( Second gnathopods feebly chelate in the male 1. Tnlifrus Latreille, 1802.

' Second gnatliopods strongly subchelatc in the male 2. Orchestoidea Nicolet, 1849.

f First gnathopods subclielate in the female 3. Orchest'ia Leach, 1814.

i First gnathopods simple in the female 4. Ta/urc/icstia J)a.na, 1852.

^ f Third nropods single-jointed, G.

( Third uropods not single-jointed, 7.

f Telson partially cleft 5. Ceina Delia Valle, 1893.

i Telson entire 0. ChUtonia, n. g.

^ r Third uropods with two rami, 8.

*- Third Tii-opods with only one ramus, 9.

(" Telson divided 7. Par/iyr/Ze Stehhing, 1897.

I Telson entire 8. Neobiile Haswell, 1880.

f. f^Iaxillipeds, fourth joint of palp not luiguiform 9. Farorchestia, n. g.

^ JMaxillipeds, fourth joint of palp ungniform, 10.

55*

f Fir

iFir

398 EEV. T. K. K. STEBBING ON AMPHIPODA FEOM

10.

11.

-Second giiathopods of tlie male, fiftli joint not produced between

the fourth and the sixtli 10. Hyale Rathke, 1837.

Second gnathopods of the male, fifth joint produced between the

fourth and the sixth, 11.

f Telson undivided 11. ffyafeWa S. I. Smith, 1875.

L Telsou more or less divided 12. ^//orc/tes/es Dana, 1849.

Talokchestia tridentata, u. sp. (Plate 30 B.)

The back is not very broad. The first four pairs of side-plates are scabrous, tlie first

shallower than the three following ; the fifth is the widest. The eyes are roughly oval,

rather more than their longer diameter apart.

First antennce. Very small, not reaching the middle of the penultimate joint of the

peduncle of the second antennre.

Second antennce. About one-third as long as the body ; the last joint of the peduncle

twice as long as the penultimate ; the flagellum scarcely as long as the peduncle, flattened,

slightly tapering, consisting of about twenty-four sliort transverse joints.

First gnathopods. Spinose, the fifth joint long, the subapical pellucid process of the hind

margin narrow, very prominent; the sixth joint much shorter, rather narrow, the apical

pellucid process prominent, the finger with sinuous inner margin, extending beyond the

apical process of the sixth joint.

Second gnathopods. The second joint is channelled in front, the apices of the front

margins being faintly lobed ; the third joint is rather larger than the fourth, neither of

them longer than broad; the fifth joint is exceedingly diminutive ; the sixth very large,

its hind margin fringed with spiniiles, the palm oblique, having near the finger-hinge a

large triaugvdar spinulose tooth, followed by a sinuous slope, and defined from the hind

margin by two tf elh side by side, only one of them being visible in a profile view ; the

finger very large, with swelling of the inner margin near the hinge ; the rest of the

margin concave, fringed with small spinules.

Second j^erceopods. This pan* is much shorter than the first. The finger has a strong

prominence near the base of the nail.

Third per (eo2)ods. This pau" is very short, the second joint nearly as broad as long.

Fourth and fifth per cEopods. These pairs are not very elongate, but much longer than

the third pair. All the perajopods are spinose, with rather small branchial vesicles.

First nropods. Long, the rami much shorter than the peduncle, both carrying-

marginal spines.

Second nropods. The rami are not shorter than the peduncle, with stout spines.

Third urop)ods. The ramus is at least as long as the peduncle.

Telson. Sliort, spinulose.

Length. Less than half an inch, 11 mm.

Hab. California. The specimen described, a male, was sent me by S. J. Holmes, Esq.,

among specimens of Orchestia traskiana.

Without knowledge of the other sex this species can only conjecturaUy be assigned to

THE COPENHAGEN MUSEUM AND OTHEE SOUECES. 399

Talorcliestia. But it shows considerable likeness to another member of that genus,

Tcdorchestia pravldactijla Haswell, wliile also the sharply notched finger of the second

peraeopods and the long fifth joint of the first gnathopods are more commonly associated

with Talorcliestia than with Orchestia. The specific name alludes to the three-toothed

palm of the second gnathopods.

Talorchestia kov.e-hollandi.«, n. sp. (Plate 31 A.)

The body is stout. In the second pleon-segment the postero-lateral corners have an

acute point ; in the third segment they are quadrate.

Eyes round, dark, al^out their diameter apart.

First aHtenncB. They reacli beyond the penultimate joint of the peduncle of the second

antennae ; the joints of the peduncle are successively shorter, none of them elongate ;

the flagellum is shorter than the peduncle and consists of six joints.

Second antennce. Verticillately spinulose, about one-third as long as the body, penul-

timate joint of the peduncle nearly four-fifths as long as the ultimate ; the flagellum is

rather shorter than the pedimcle, and is composed of nineteen rather short joints.

First (jnatliopods. d . The second joint bulges considerably from the narrow neck

and then narrows again slightly ; the fifth joint is longer than the sixth, and has a

prominent but narrow apical process of the hind margin; the sixth joint is rather short,

much widened distally, the finger overlapping the true palm, but not the advanced

rounded process of the hind margin, against which its apex impinges.

Second gnathopods. 6 . The second joint is comparatively narrow, the third rather

larger than the fourth, the fifth diminutive ; the sixth very large, slightly widening to

the almost transverse palm, which, as so often occurs, has at the defining angle a small

pocket, a broad convexity leading thence to a spinulose concave space near the finger-

hinge, over which space the finger arches, leaving an interval, the convexity of its

sinuous margin then touching the convexity of the palm and its apex passing into the

defining pocket.

First gnathopods. 2 . The fifth joint has no apical process of the hind margin ; the

sixth is short, strongly spined, narrowing gradually to the short finger, the base of which

occupies its rounded apex.

Second gnathopods. ? . The second joint is membranous, well expanded ; the sixth joint

nearly as long as the fifth, rather narrow, produced as usual beyond the minute palm, to

which the finger is adjusted in a rather oblique position.

Second per (copods. The finger is sharply notched near the nail.

Third peneopods. These are short, with the broadly expanded second joint almost as

broad as long.

Fourth perceopods. Much longer than the third pair.

Fifth pera'opods. These are longer than the fourth pair, and have the second joint

broader, with subquadrate apex to its hind margin ; the fourth and fifth joints rather

broad, but at the same time elongate ; the sixth joint long and narrow. All the peraeopods

have numerous spines on both margins.

400 REV. T. E. K. STEBBING ON AMPHIPODA FEOM

Uropods. These all have marginal spines on tlie peduncles and rami.

Third it7'opods. The ramus is slender, shorter than the peduncle.

Telson. This is peculiar, much longer than broad, composed of separate halves, wliich

appear to fold closely together, each carrying two apical spinules and two well-separated

marginal spines.

Colour. Dusky in spirit.

Length. About two-fifths of an inch, 10 mm.

Hah. Australia, Manly Beach. Two specimens were forwarded to mc by Mr. Thomas

Whitelegge, of the Australian Museum, with the label, " Talorcheslla novoi-hollandicc.

H. Manly Beach." The specimens wore c? and ? .

Talorchestia Deshatesii (Audouin). (Plate 30 A.)

1825. Orchestia Deshayesii Audouin, Explication des Planches de Savigny, Atlas, j)l. ] I. fig. 8.

1893. Talorchestia Deshaye.n Clievreux, Bulletin de la Societe Zoologique dc France, vol. xviii. p. 127,

fig. in text.

Por the remaindei' of the synonymy of tliis well-known species reference may be made

to the 'Challenger' Amphipoda and Delia Valla's Gammarini. The specimen here

figured is a young male. It exliibits a form of the second gnathopod closely agreeing

with that which Barrois lias figured as lielonging to an individual with eighteen joints

in the flagellum of the second antennae. The individual here" figured has tliat precise

number of joints in the flagellum. Professor Th. Barrois Avas the first to call attention

to the transformations througii which the second gnathopod passes in the male of this

species. It begins with a feebly chelate form. Gradually the palm becomes transversely

excavate and defined by a blunt double tooth. The tooth becomes single, the palm

becomes oblique, and finally in the adult stage there is an acute tooth, which, so far from

chelately overlapping a small finger, has shrunk back to the very base of the hand, and

a very long finger curves to meet it over a long straight extremely oblique palm.

The specimen was obtained for the Copenhagen Museum from Constantin, in Algeria,

by Dr. Meinert.

I have a specimen with the adult form of the gnathopod on one side, and on tlie

other the juvenile, the latter no doubt representing a limb that has been lost by some

accident.

M. Ed. Chevreux Avas the first to show that in the female the fii-st gnathopod is simj)le,

so that the species is more properly referred to Talorchestia than to Orchestia.

The species is frequently to be met with on the sandy shores of North Devon. Its

European distribution is very extended.

Orchestia Stjlensoni, n. sp. (Plate 30 C.)

The integument, as preserved in spirit, is membranaceous and iridescent. The third

and fourth pairs of side-plates are little deeper than the fifth and sixth. The third

pleon-segment has the postero-lateral corners quadrate, the point scarcely produced.

Eyes not very large.

THE COPENHAGEX MUSEUM A.XD OTHER SOUKCES. 401

First anteniue. Tlie first joint is very small, at least as broad as long; the second and

third joints are each slightly longer ; the fiagcUuni consists of four joints, together about

as long as the third joint of the peduncle.

Second antenme. The peduncle is large and stout, its penultimate joint about three-

fourths as long as the iiltimate, and not stouter. The flagellum is shorter than the

peduncle, and on one side of the specimen contained tv\enty-one jijints, on the oilier side

eighteen .

First (jnuthopoijs. The second joint is nari-ow at the base, and then becomes rather

broad ; the fourth has no apical process ; the fifth aa idens to a distal, pellucid, prominent

but narrowly rounded process of the hind margin; the sixth joint, which is twu-thirds

the length of the fifth, is oblong, widening very slightly to the palm, which has no

conspicuous process, and is overlapped by the small iinguiculate finger. Both the fifth

and sixth joints are beset with a moderate armature of spinules.

Second (jnatliopods. The second joint is not very wide, though for most of its length

much wider than at the base. The tliird and fourth joints are very small, but larger

than the almost evanescent fifth. The sixth joint is very large, fringed Avith spinules

on the hind margin, widening to the palm, which is moderately oblique, spinulose,

smoothly convex between a blunt defining tooth and a deep depression near the tinger-

hino-e, the depression corresponding with a rounded process of the finger's inner margin;

the large curved tinger matches the palm.

First and second j^ierceoipods. These are slender, the tirst pair conspicuously longer

than the second, the short tinger of the second ha\ ing, as usual in the genus, its inner

margin indented.

Third, fourth, and jifth ferceopods. Of these the third is much smaller than either of

the others. In all the second joint is oval, but in the tilth pair, in which it is largest,

the oval is modified by the comparative straightness of the hind margin. In the fourth

and fifth pairs the joints following the third are rather long and narrow.

First iiropods. The upper ranuis has lateral as well as apical spines, and is rather

shorter than the lox^er ramus, which has only apical spines.

Second iiropods. The rami are equal, and both have lateral spines.

Third u-ropods. The ramus is not half as long or half as broad as the peduncle. It is

armed with a row of three spinules.

Length two-fifths of an inch, 10 mm. Prom the size of the second gnathopods and

powerful second antennae in the single available specimen it may be inferred to be an

adult male. It agrees with the imperfectly described Orchestia tucurauna of Fritz

Miiller in regard to the finger and the notched palm of the second gnathopods, but

jMiiller lays stress on the fact that these characters are combined with incrassated fourth

and fifth joints of the fifth perteopods in his species, the younger males with slender

peraiopods having also a smooth palm to the gnathopods and the second antennae

slender.

Hah. Ihe specimen, which belongs to the Copenhagen Museum, was labelled

" Madeira ? Suleuson."

The specific name is given in compliment to the traveller who procured the specimen.

402 REV. T. E. E. STEBBING ON AMPHIPODA FROM

Orchestia grillus (Bosc).

1802. Talitrus grillus Bosc, Histoire Naturelle des Crustacees, vol. ii. p. 152, \i\. 15. figs. 1, 2 (called

on the plate ' Thalitre terrestre ') .

It is not necessary here to discuss the synonymy of this species, which nearly resembles

Orchestia gammarellus (Pallas). It is only mentioned for the sake of recording an

abnormality in a male specimen belonging to the Copenhagen Museum. The second

peraeopod on the right side has been cicatrized near the base of the fourth joint, but

attached to the same side-plate that carries the damaged limb is a limb with the full

number of joints, though these are less strongly developed than those of the limb on the

left side or than the remaining joints of the broken limb.

JTah. The specimen is labelled " New York Omegn, L. Lund," meaning that it was

obtained by L. Lund in the neighbourhood of New York.

Parorchestia, n. g.

Like Orchestia, except that the maxillipeds have a fourth joint to the palp, distinct,

though small, conical, and airrying a spine on the truncate aj^ex.

The name is derived from -Tru^a, near, and Orchestia. The genus is formed to receive

the species (1) Orchestia tennis Dana, with which the Allorchestes recens of G. M.

Thomson seems to be identical; (2) Orchestia hawaiensis Dana; and (3) Orchestia

sylvicola Dana.

Hyale Galate^e, n. sp. (Plate 31 B,)

The species occurs both in the Atlantic and the Pacific, with the slight difference that

in the Atlantic specimens the integument appears to be smooth, while in those from the

Pacific the back and to some extent the appendages are scabrous, with little hairs or

scales like a capital T inverted. The first side-plates are widened below, the second and

third pairs are not very deep. The third pleon-segment has the postero-lateral corners

quadrate.

Eyes. Large, oval, black, nearly meeting at the top of the head.

First antenna. Much longer than the peduncle of the second antennae ; joints of the

peduncle small, successively shorter ; flagellum in d with nine, in 2 seven, distally

Avidened joints.

Second antennce. About one-third as long as the body ; last joint of the peduncle

considerably longer than the penultimate ; flagellum of d with twelve to fourteen, of

$ nine joints.

First maxillce. The palj) has a small constriction.

Maxillipeds. The curved fourth joint of the palp is slender.

First gnathopods. 6 ■ The second joint is short and broad, with narrow base ; the

fourth is distally squared ; the fifth is as broad as long, with a rounded lobe behind

carrying spines along the somewhat flattened hind margin ; the sixth joint is rhomboidal,

distinguished by a small hump at the centre of the long front margin, the much shorter

THE COPENHAGEN MUSEUM ANU OTHER SOUECES. 403'

concave hind margin making an angle before it joins the oblique spinuliferous palm,

from which it is defined by a jKxhnar spine that antagonizes with the apex of the cvirved

finger.

Second gnathopods. d ■ The second and third joints are distally lobed in front ; the

fourth has the apex broadly rounded ; the fifth is very short, with the little horny-

lookiug process from the hind margin on either side more conspicuous than usual ; the

sixth joint is large, widest where the short, smoothly curved, hind margin meets the long,

very oblique, Jiearly straight, spinulose palm, and narrowest at the hinge of the long

curved finger, which has a strong bulb at the base of its inner margin.

Fif^si and second gnathopods. £ . Small, the fifth joint short, the sixth oblong,

slightly Avidened at the rather oblique, spinulose palm. The second pair are a little the

longer.

Ferceopods. These are moderately robust. The finger has a minute inner setule. In

the last three paii's the second joint is broadly oval, nearly smooth on the hind margin,

the lower part of the wing in the fifth pair being broadly produced downward.

First and second uropods. In both pairs there are lateral as well as ajjical spines on

both rami.

Third uropods. The ramvis is a little shorter than the peduncle, with spiniiles at or

near the apex.

Telson. The lobes have the proximal half of nearly uniform width, the distal half

triangular.

Length. About one-sixth of an inch, 4 mm.

Sab. Pacific and Atlantic. Specimens belonging to the Copenhagen Museum were

taken at various localities, at different dates, by sevex'al naturalists, as appears from the

labels, " ' Galatea,' 6. 8. 46. Rhdt." ; " 37° 32' N., 179° 43' E., 15. 3. 46. Reinhardt " ;

" 4° 30' N., 137° E., 8. 11. 75," " Caspersen " ; while in the Atlantic one specimen,

6, was obtained from the Sargasso Sea by " Eriis, 1861," and one specimen, $,

" 26° 20' N., 58^ 40' W., 6. 2. 96. Chr. Levinsen," the last locality also corresponding

with the Sargasso Sea.

Htale diplodactyltjs, n. sp. (Plate 31 C.)

The first and second side-plates are not very deep, and the first are but little widened

below.

Eyes. Hounded, light-coloured in spirit.

First antennce. Much longer than the peduncle of the second pair ; the peduncle is

short, the second joint much shorter than the first, and the thii'd than the second ; the

flagellum in the 6 has fourteen joints, in the $ nine.

Second antennce. The last joint of the peduncle is rather longer than the penultimate ;

the flagellum in the c? has twenty-six joints, in the $ seventeen.

First gnathopods. d . The second joint is rather short, narrow above, broad below ;

the fourth joint is distally squared, supporting the spinose hind lobe of the fifth joint,

which throws out this lobe beyond a short distal piece of its hind margin ; the sixth

SECOND SERIES. — ZOOLOGY, VOL. VII. 56

404 llEV. T. E. E. STEBBING ON AMPHIPODA FEOM

joint widens greatly to the palm, with the hind margin sinuous, much shorter than the

smoothly curved front ; the palm long, not very oblique, excavate, ending in a wide

pocket, which receives the deeply furcate end of the finger, which is thus wdder distally

than at its base.

Second gnatlioiwds. 6 • These scarcely differ from those of Hyale Galatea;, except that

the expanded front margin of the second joint is closely fringed with setules, and the

sixth is widest near to the base instead of at the junction of the hind margin with the

long, very oblique palm.

Telson,. In situ this is rather markedly upturned, with a slight twist to the blunt

apex of each triangularly ending lobe. In other respects this species appears in both

sexes to agree with Syale Galatece, except that the size is a little greater.

Length. S rather over, 2 rather under one-fifth of an inch, 5 mm.

Hah. St. Croix. The specimens belonging to the Copenhagen Museum were obtained

by Oersted in the Danish West Indies.

The specific name refers to the double-ended finger in the first gnathopods of the

male.

Hyale macrodactylus, n. sp. (Plate 31 D.)

The side-plates are not deep ; the first is distally widened, the fourth is wide, with

deep hind emai'gination. The third pleon-segment has the postero-lateral corners

quadrate, the angle scarcely produced.

Eyes. Not large, rounded, wider apart than their diameter.

First autenitcv. The pedimcle is short, its first joint suhequal to the second and third

combined ; tlie flagellum consists of thirteen joints, of which those near the base are

short.

Second antennce. More than half as long as the body ; the last joint of the peduncle

longer than the short j)enultimate ; the flagellum containing twenty-five joints.

First gnafliojwds. d . The second joint is short and broad except at the base ; the third

has a small front lobe ; the fourth an acute hind apex ; the fifth is lobed much as in

Hyale dlplodactylus ; the sixth is oblong oval, the palm oblique, spiuulose, sejDarated

from the hind margin by a rounded angle carrying a palmar spine, against the inner side

of which the apex of the finger closes.

Second gnatho^wds. j . The second joint is lobed at the distal end of tlie front

margin ; the third is lobed in front ; the roixnded apex of tlie fourth touches the base of

the sixth ; the fifth is small, triangular, with length and breadth suhequal ; the sixth is

elongate, widest at the base, the front margin smoothly convex, the palm closely frmged

with slender spinules and extending almost the whole length of the joint, its nearly

straight line broken only by a shallow emargination between two slight swellings, one

of which is close to the finger-hinge; the long, blunt, slightly sinuous finger can reach

the apex of the fourth joint.

First and second gnathopods. $ . The sixth joint is narrowly oblong.

Fe^'ceopods. In these the sixth joint at the apex of the inner margin carries a strong

THE COPENHAGEN MUSEUM AND OTHER SOURCES. 405

blunt spine, mth a similar but much sliortev one below it ; the finger ciu-ved, its inner

setule minute. In the third and fifth pairs the second joint is somewhat orbicular ; in

the fourth pair it is oblong oval, rather wider above than l)eloAV.

First and second nropods. Both rami have lateral sj)ines.

Third uropods. The ramus is as long as the peduncle.

Telson. The lobes are bluntly triangular.

Length, xibout one-sixth of an inch, 4 mm.

Hab. St. Thomas's Harbour. The specimens, which belong to the Copenhagen

Museum, were obtained in the Danish West Indies by Clir. Levinsen, and reached me

mixed with specimens of Hyide Perierl (Lucas) and Si/cde media (Dana).

A specimen in the same collection, from Rio Janeiro, is probably a younger form of

the male of this species. It has a flagellum of ten joints to the first, and one of

eighteen to the second, antenna\ The first gnathopods are without the strong bulging

at the juncture of the palm with the hind margin. The second gnathopods have the

long oblique palm smoothly curving and defined from the short liind margiai by a small

pocket, which the long finger reaches.

Htale marotjbrjE) n. sp. (Plate 32 C.)

Body rather compressed, shining. Third pleon-segment with postero-lateral corners

quadrate.

Eyes. Roughly rounded, about their diameter apart, moderately dark in spirit.

First antenncs. These reach well beyond the peduncle of the second jiair. The

peduncle is short, the first joint equal to the second and third combined ; the flagellum

has nine slender joints.

Second antenna;. About half the length of the body ; the flagellum longer than the

peduncle, slender, composed of nineteen joints.

First gnathopods. 6 . The fourth, fifth, and sixth joints are subequal in length ; the

fourth has a produced, broadly-rounded apex, carrying one or two spinules ; this apex is

separated from the sixth joint by the rounded hind lobe of the fifth, which is fringed

with about eight graduated spines ; the sixth joint is oblong, but scarcely longer than

the width, which is rather greater at the j)alm than the base ; the hind margin from

near the base is fringed with spinules which pass round on to the surface and meet a

transverse row of small spinules, across which the short finger closes, as though they

represented the true course of the j^alm, but the hinder half of the distal margin of the

sixth joint extends beyond these in a microscopically denticulate lobe at right angles to

the hind margin, though the junction is rounded ofi".

Second gnathopods. d . The second joint is slightly lohed at the front apex, down-

ward, not outward ; the third joint has a small outward lobe ; the fourth joint is small,

a little produced at the hind apex; the fifth is very small, triangular; the sixth very

large, oval, broadest proximally, the hind margin very short, the spine-fringed palm

very oblique and long, well defined, the long finger nearly reaching the fourth joint, its

56*

106 KEY. T. E. E. STEBBING ON AMPHIPODA FEOM

apex when closed passing on the inner side of the palmar spine into a pocket on the

surface of the sixth joint. Tlie branchial vesicles are very small.

Feroiopods. These are of medium robustness and the usual relative proportions, but are

distinguished by the apical spines of the sixth joint. As in various other species, the

large distal spine which antagonizes with the finger is blunt-headed, with the margin

partially serrate, Init the smaller spine between this and the finger is bent up to meet

it, and is not tapering or parallel-sided, but from the neck onward of fusiform appearance,

with numerous lines or grooves parallel more or less to the outline ; the setule on the

inner margin of the finger is extremely small. In the last three pairs the second joint

has the hind margin crenulate, but not strongly.

Fi7~st nropods. The rami are as long as the peduncle, and neither of them is devoid of

lateral spines.

Second nropods. The rami are unequal, longer than the jjeduncle.

Third nropods. The ramus is moderately slender, as long as the peduncle, both with

apical spines only.

Telson. Cleft to the base, slightly broader than long, the lobes distally somewhat

acutely triangular.

Length. One-fifth of an inch, 5 mm.

Hob. Australia; Maroubra Bay, near Sydney, New South Wales. The specimens

occurred in a gathering sent me by Mr. Thomas Whitclegge, " obtained by washing the

seaweeds from low tide-line."

By the structiu'e of the first gnathopods and the peculiar spines of the perseopods this

species seems to be easily distinguishable from all hitherto described.

Htalella Warmingi, n. sp. (Plate 32 A.)

The body is rather robust ; the sixth side-plates are deeply lobed behind ; the third

pleon-segment has the postero-lateral corners a little produced backward, acute.

Eyes. Small, dark, wider apart than their diameter.

First antenncc. The second joint is scarcely shorter than the first, the third a little

shorter than the second ; the flagellum has thirteen joints in the <j , ten in the ? .

Second, antennee. More than half as long as the body, the gland-cone prominent, the

last joint of the peduncle a little longer tlian the penultimate ; the flagellum shows

nineteen joints in the S , fifteen in the ? .

First maxiUce. The palp is minute.

Ma.villij>eds. Third joint of palp distally widened, fourth with curved spine on the

blunt apex.

First gnathopods. 6 . The fifth joint has a- subapical group of spines on the front

margin, and the bulging hind margin fringed with graduated spines; the sixth joint is

shorter, widening, with sinuous hind margin to the transverse palm, which is defined by

a process within Avhich the finger closes ; there is an oblique row of spinules on the

surface.

Second gnathopods. $ . The second joint is slender, not lobed Ijelow ; the fifth short,

THE COPEXHAGE]^ MUSEUM AND OTHER SOURCES. 407

the fringed cup-like process well produced ; the sixth joint large, oval, the very oblique

sinuous palm forming three lobes, of which the centre one is broadest, the finger

closing at the tliird into a pocket which meets the hind margin at a well-defined

angle.

First and second gnathopods. $ . These are similar to the first in the 6 , but smaller,

and the sixth joint of tlie second is rather longer and more slender than that of the

first.

Pcrceopods. These are tolerably robust and spinosc. In the last three pairs the second

joint is l)roadly oval, considerably larger in the fifth than in the two preceding pairs.

There are simple accessoi-y branchiae on the first four pairs of the peraeopods.

First and second nropods. These have lateral spines on both rami.

Third iiropods. The ramus is as long as the peduncle.

Tel son. Squared at the base, then broadly rounded, with two distant setules on the

broad apical margin.

Colour. Dusky in spirit.

Length. A fifth of an inch, 5 mm.

Hub. Lagoa Santa, from watercourse. The specimens belong to the Copenhagen

Museum, and were obtained by Warming, after whom the species is named. The

species seems most nearly related to Hyulella Lnbondrskii (Wrzesniovvski), to judge by

the description of tliat species, which is unhappily unaccompanied by figures.

Htalella Meinerti, n. sp (Plate 32 B.)

The first three pairs of side-plates are deeper than broad ; the third plcon-segment has

the postero-lateral corners acutely qiiadrate.

Eyes. Black, usually wider apart than their diameter.

First antennce. Slender, more than half as long as the second pair; third joint of the

peduncle nearly as long as the second, but by its slenderness resembling the joints of

the flagellum ; flagelhim composed of nine or ten elongate joints.

Second antennce. Slender, more than half as long as the body ; penultimate joint of

peduncle rather long, ultimate still longer, the flagellum consisting of thirteen to fifteen

elongate joints.

First gnathopods. 6 . The fourth joint has a scabrous, rather prominently rounded

apex ; the fifth is strongly widened distally, with the projecting apex scabrous and

rounded ; the sixth joint is much shorter, scarcely widening to the transverse well-

defined palm, and, as is so commonly the case i]i the genus, inclined athwart the

preceding joint.

Second gnathopods. 6 . The second joint is narrow, the fourth as in the preceding

pair ; the fifth with the usual cup-like spine-fringed lobe ; the sixth mucli longer than

broad, its basal part narrow, rather abruptly widening at the boss which defines the

-oblique, slightly sinuous palm, the finger closing completely over the palm, with its

apex on the surface within the boss.

First and second gnathopods. 2 . These are small ; the fourth joint has a rounded

408 EEV. T. E. E. STEBBING ON AMPHIPODA FEOM

apex ; the sixth in the iirst pair is shorter than the fifth, but in the second at least as

long, in both narrow, oblong, narrowest at the base, with tlie short palm transverse or

slightly tending to form an acute angle with the hind margin.

Perceopods. The fourth pair are rather longer than the third, and the fifth than the

fourth. In the third and fourth pairs the second joint is oval, in the fifth pair it is

much wider, with flattened front and very convex hind margin. There are accessory

brancbifc to all the five pairs. The ordinary brancbias were not perceived on the fifth

pair.

TJropods. These are unusitally slender. The first and second pairs have lateral spines

on both rami. The third pair are comparatively long, the tapering ramus rather longer

than the peduncle, and extending considerably beyond the telson.

Tel son. Oblong oval, with a pair of spinules on the rovmded apex.

Length. A fifth to a quarter of an inch, 5-6 mm.

Hab. Laguno di Espino. Sjiecitnens belonging to the Copenhagen Museum, obtained

by Dr. Meinert, in compliment to whom the species is named.

In regard to the first and second antennae this species agrees closely with Faxon's

" Allorchestes dentatus, var. ffracilicornis," and in other respects with his " Allorchestes

longistilus " ; but for neither of these forms is any mention made of accessory branchiae,

nor do those appendages appear to be present in Hyalella iiiermis S. I. Smith, to which

Faxon's species are closely related.

Chiltonia, n. g.

First four pairs of side-plates deep. First and second antennae equal in length. First

maxillae without palp, although distinctly notched at the palp's usual position. Maxil-

lipeds with the fourth joint of the palp small, conical. Other mouth-i^arts as in the

family character. First and second gnathopods sulichelate, the second differing greatly

in the two sexes. The third uropods one-jointed. Telson simple.

Name of the genus given in compliment to Dr. Charles Chilton, M.D., D.Sc, F.L.S.

Chiltonia mihiwaka (Chilton).

1898. Hyalella mihiwaka Chiltou, Annals and Magazine of Natural History, ser. 7, vol. i. p. 423, pi. 18.

The typical species has been very accurately described and figured by Dr. Chilton,

who has obliged me with specimens. It seems possible that the pear-shaped third

uropods may represent a peduncle and ramus coalesced into a single joint.

" Colour. Greyish or nearly white.

" Size. Largest specimens about one-fifth of an inch (5 mm.).

" Hah. Mountain -streams near Port Chalmers, up to about 1500 feet above sea-level

{Chilton). In hillside stream at East Taieri ; from spongy moss at top of Mount

Cargill, 2200 feet, and on Swampy Hill, 2400 feet {G. 31. Thomson)."

THE COPENHAftEX MUSEUM AXD OTHER SOUliCES. 409

Alloechestes malleolus, u. sp. (Plate 33 A.)

The body is moderately compressed. The first four pairs of side-plates are rather

■deep, without the projecting point of the hind margin found in many of the Orchestiidae.

The third jileon-segment has the postero-latcral angles bluntly produced.

El/cs. Xot large, rounded, dark in spirit, at least as far apart as their diameter.

First antenna'. About three-quarters as long as the second pair; the second joint a

little shorter than the first ; the third considerably shorter than the second ; the flagellum

longer than the peduncle, with ten to twelve joints.

Second mitennce. Not more than one-third as long as the body ; the peduncle stout ;

the last joint a little longer than the penultimate ; the flagellum shorter than the

peduncle, consisting of ten to twelve joints. In young from the marsupium the first

antennae are not shorter than the second ; the flagellum in each pair is limited to two

or three joints.

First miixiUce. The palp is minute, on a well-defined interruption of the hind margin

of the outer plate.

Second ma.villcc. The princijial seta on tlie inner margin of the inner plate is not

very elongate.

First gnathopods. d . The second joint widens rapidly to the middle ; the fourth is

not longer than the third ; the fifth little longer than the sixth, widest subapically, with

spines on l)oth margins at the widest part ; the sixtli widening to a sort of palmar angle,

a part of the sinuous hind margin being adapted to rest on the hind process of the fifth

joint, the margin then abruptly turning to join the short spinulose palm, which is

exactly fitted by the stout two-pointed finger.

Second g/iaihopods. c? . The second joint has no conspicuous distal lobe. The fourth

is produced, but not acutely ; the fifth is produced into a shallow, fringed, cup-like

process ; the sixth is oval, the finger closing over an oblique, almost straight palm into

the usual pocket, armed with two palmar spines ; the hind margin not at all bulging,

carrying spinules at two points.

First gnathopods. ?. The fourth and fifth joints are as in the male; the sixth is

oblong, slightly widening to the transverse palm, the hind margin sinuous, the finger

acute, closely fitting the palm.

Second gnathopods. 2 . These are larger than the first pair, though very small

compared with the second pair in the male. The fourth joint is subacutely jn'oduced ;

the fifth is shorter than the sixth, distally wider than the length, tlie process fringed

with spinules ; the sixth joint is oblong, slightly widened distally, the hind margin

straight, the finger acute, scarcely reaching the end of the transverse palm. In young,

taken from the marsupium, the first and second gnathopods have a general resemblance

to the first gnathopods of the adult female. The marsupial plates of the second

gnathopods and first pera:;opods have one distal corner subacutely produced ; those of

the second perteojiods end squarely ; in all, the fringing setae are short.

Ferceopods. None are strungly spiued. The finger is curved ; in the last three pairs

the second joint is oblong oval, the front margin nearly straight, the hinder produced

410 REV. T. E. E. STEBBING ON AMPHIPODA FEOM

downward in a rounded lobe ; in the fourth pair this joint is more oblong than oval,

widest proxitually, whereas in the fifth pair it is much l)roader and widest distally. In

the female the last three pairs are shorter and stouter than in the male, with the fourth

joint more widened distally.

Pleopods. There are two or three coupling-spines on the peduncle, and on the inner

margin of the first joint of the inner ramus four to five spines, not cleft, but at the

apex a little dilated and hooked.

Uropods. Small ; first pair with lateral spines on only one of the rami ; third with

the small ramus sliorter than the peduncle.

Telson. Nearly square when flattened out, with slightly convex sides, the cleft not

reaching beyond the middle, its sides not divergent.

Length. About 7 mm.

Eab. Korean and Japanese waters : 31° 40' N., 125 50' E., Tong-kai, in seaweed

{Studer collection); M 14' N., 129 34' E., in seaweed, Korea (Andrea); 34° 40' N.,

129° 50' E., Japan {Andi-ea) ; BT 0' N., 131 20' E. [Studer collection) ; Wladiwostock ?

(H. Koch) ; all the specimens belong to the Copenhagen Museum.

The specific name refers to the hammer-like appearance of the first gnathopods of

the male.

Alloechestes compressus Dana. (Plate 33 B.)

1852. Allurchestes compressa Dana, Proceedings of the American Academy of Arts and Sciences, vol.^ii.

p. 205.

1852. Allorchestes austruiis Dana, P. Amer. Ac. vol. ii. p. 20G.

1853. „ Gaimnrdin Dana, United States Exploring Expedition, vol. xiii. p. 884., pi. 60.

fig. 1 a-i.

1853. Allorchestes australis Dana, U.S. Expl. Exp. vol. xiii. p. 892, pi. 60. fig. 7 a-o.

1862. „ Gaimardii Bate, Catalogue of Amphipodous Crustacea in the British Museum,

p. 41, pi. 6. fig. 9.

1862. Allorchestes australis Bate, Catal. Amph. Brit. Mus. p. 45, pi. 7. fig. 6.

1881. Aspidophoreia diemenensis Haswell, Proceedings of the Linnean Society of New South Wales,-

vol. V. p. 101, pi. 6. fig. 2.

1893. Allorchestes {Hyale?) compressa Delia Valle, Fauna und Flora des Golfes Neapel, Monograph 20,

p. 528 {see also pp. 519, 523).

1893. Aspidophoreia (Hijale ?) diemenensis Delia Valle, F. u. Fl. G. Neapel, Mon. 20, p. 530.

The body is compressed, especially at the pleon. The first four pairs of sidc-j)lates

are deep, the fourth being also wide ; the second to the fourth are quadrate, the fifth is

shallow. The postero-lateral corners of the third pleon-scgment are quadrate, with

minutely-produced point.

Eyes. Oval, wider apart than the longer diameter.

Antennce. In young from the marsupium the two pairs are equal ; in the adult the

proportions are rather variable. As Bate jioints out, Dana mistook a fused portion of

the flagellum in the second pair for a joint of the peduncle.

First antenna'. Usually rather longer than the peduncle of the second pair ; flageUum

consisting of from ten to twenty joints.

THE COPENHAGEN MUSEUM AND OTHEE SOUBCES. 411

Second anteniKB. Flagellum much or not much longer than the peduncle, having

from ten to twenty joints.

Up2)er lip. Broader than deep.

First maxilliJE. Palp minute.

Maxillipeds. Second and third joints of palp broad.

First (jnatliopods, d . Fifth joint slightly longer than sixth, widest suhapically, with

spinules at j)rojections of front and hind margins ; sixth oblong, a little widened at the

almost transverse convex palm ; the finger matches the palm.

Second gnathopods, d . llobust, the second joint with small downward-produced lobe,

the third also with the front lobed, the fourth apically produced behind, the fifth produced

backward in a rather slender and not strongly spined lappet, the sixth large ; the palm

spinulose, very oblique, defined from the slightly bulging hind margin by palmar spines

and the small hollow which receives the apex of the strong finger

First gnathopods, 2 ■ These are as in the male, except that the sixth joint is more

elongate, equal to the fifth.

Second gnathopods, 9 . Rather larger than the first ; the second joint not produced

downward, the third without conspicuous lobe, the fourth as in the male, the fifth with

its lappet stretching along part of the straight hind margin of the sixth, the sixth

broader than in the first pair, slightly widening to the transverse palm, which the finger

matches. The branchial vesicles are large, oval, with narrow neck. The marsupial

plates are broad, oblong, produced at one corner, their setse short.

First and second perceopods. Subequal, slender.

Third perceopods. The second joint is oblong oval, the front margin carrying spines,

nearly straight, the hind margin nearly smooth ; the fourth joint is widened, spinose on

both margins.

Fourth perceopods. Considerably longer than the third, but with the second and fourth

joints not quite so wide ; the branchial vesicles in both these pairs have an accessory

lobe.

Fifth perceopods. These are shorter than the fourth pair, especially in the male, but

they have the second joint much larger and more rounded behind, widest suhapically

and broadly produced behind the third joint ; the fourth joint not much widened ; the

finger, as in the other pairs, short and curved.

First uropods. The rami are decidedly shorter than the peduncle.

Second uropods. The rami are a little shorter than the peduncle.

Third uropods. The ramus is small, coniail, shorter than the stout peduncle, tipped

with a minute spinule.

Telson. Broad ; the two quadrate lobes, separated by a linear fissure, are set at an

angle one to another, gable-like.

Colour. For Aspldophoreia diemenensis Professor Haswell says : " surface (in the

spirit specimen) ornamented with marbled spots of red, brown, and white, and with

numerous, very minute, white dots, arranged in clusters of three or four."

Length. For A. Gaimardii Dana gives the equivalent of 14-16 mm., Bate 18 mm.;

for A. austrcdis Dana gives 12-13 mm. ; for ^. diemenensis Haswell gives 20 mm. ; some

SECOND SERIES. — ZOOLOGY, VOL. VII. 57

412 EEV. T. K E. STEBBING ON AMPHIPODA FEOM

unnamed s|jecimens kiiully sent me by Professor Haswell, and whicU I refer to tliis

sj)ecies, measured about 11 mm.

Hab. Shores of lllaM'arry, New South Wales {A. Gaimardii and A. australis Dana) ;

South Australia [A. Gaimardii, Bate) ; Tasmania {A. diemenensis Haswell) ; Jervis Bay,

Australia (the specimens above-mentioned, received from Professor Haswell).

Allorchestes plumicoknis (Heller). (Plate 33 C.)

1866. Nicea phimicornis Heller, Denkschrifteii der k. Akad. d. Wissenseli. luatli.-iiatiirw. CI. vol. xxvi.

p. 5, pi. 1. figs. 8, 9.

1893. Byale Frevosiii Delia Vallc, F. u. Fl. Neapel, Mon. 20, Gammarini, p. .119.

The body is compressed and the back smootli. The first side-plates widened below.

JSi/es. Elongate rounded, lilack.

First aiitennce. They reach along nearly half the flagellum of t!ie second pair. The

fii"st joint is longer tlian the second, the second than the third, which itself is not very

short: the tiagellura is much longer than the peduncle, of about eighteen successively

lengtlieniug joints.

Second antennce. The flagellum is longer than tlie peduncle, of twenty-two joints ; the

terminal joints of the peduncle and first half of the flagellum are clothed ])eIow with

long fascicles of setae.

First maxillce. The palp reaches the base of the spines of the outer plate.

Ilaxillipeds. Tlie third joint of the palp is setose, the fourth long, acute.

First giiathopods, d . The second joint rapidly widens from the narrow base ; the

fourth has a bluntly-produced apex ; the fifth forms a broad hind lobe, fringed along the

hind margin with graduated spines ; the sixth is oblong oval, rather longer than the fifth,

M'idening slightly to the straiglit, oblique, spinulose palm ; the finger thick, M'ith outer

margin abruptly curving to an acute apex.

Second gnatliopods, 6 . The second joint is rather narrowly produced downward in

front; the fourth bluntly produced behind; the fifth very short, but wide, eml)racing

the base of the large oval sixth joint, which has a small groiip of spinules on the hind

margin ; the palm obliqixe, well defined by its angle and palmar sj)ines ; the finger strong,

acute, much curved.

Ferceopods. The fifth pair is like the fourth, but rather longer ; the sixth joint slender,

straight ; the finger acute, little carved ; the setule of its inner margin prominent, as in

all tlie peraio^wds.

TJropods. All the rami have marginal spines. In the third pair the peduncle is rather

shoi'ter than the telson, the ramus nearly as long as the peduncle.

Telson. Cleft to the base ; the lobes below the middle narrow to rounded, well-

separated apices. As usual, the lobes in situ are inclined one towards the other.

Length. 9-11 mm.

Mab. Mediterranean, at Eagusa in the Adriatic, at Genoa, and at Villefranche.

Male specimens from Villefranche have been kindly sent me by the well-known cur-

cinologist, M. Ed. Chevreux. According to Heller, only females were known to him ;

THE COPENHAGEX MUSEUM A^■D OTHEK SOUECES. 413

but I feel convinced that his figures and description refer to the male sex. Tlie hirsute

second anteunte and the great ditFerence in the size of the two pairs of gnathopods are

strong evidence of this.

Allorchestes humilis Dana. (Plate 33 D.)

1852. Allorcliestes humilis Dana, P. Aiuer. Ac. vol. ii. p. 2()().

1853. „ „ Dana, U.S. Expl. Exp. vol. xiii. p. 890, pi. 60. fij;. 6 a-e.

1862. „ „ Bate. Catal. Anipli. Biit. Mus. p. 45, pi. 7. fig. 5.

1893. ? Ill/ale Prevostii, ? , Delia Valle, F. u. Fl. G. Neapel, Mon. 20, Ganimarini, p. 528.

Eyes. A little oblong, according to Dana. In Saghalien specimens, small, round,

light-coloured.

First antennce. A little shorter than the second pair ; the peduncle two-thirds as long

as the peduncle of the following pair; the flagellum containing from six to eight joints,

which are very distinct, with moniliform appearance, and long filaments on the widened

apices.

Second aiiteiDice. About one-third tlie length of the body ; the last two joints of the

peduncle subequal; the flagellum containing nine to ten joints, which are not very long

nor distally widened ; the seta; being in Dana's account all very short, but not very short

in Saghalien specimens.

First moxillce. The palp reaches the base of the spines of the outer plate.

MaxilHpeds. The third joint of the palp is said by Dana to be narrow, nor is it wide

in the Saghalien specimens ; but this joint often looks mvich narrower than it is, unless

specially flattened for examination.

First gnathopods. The fifth joint is scarcely longer than broad ; the sixth is much

longer, oblong, widening to the oblique, spinulose palm, which is shorter than the spinu-

liferous hind margin, and has a strong palmar spine.

Second giuithopods. These are very similar to the first pair, and the sixth joint, though

considerably, is not exorbitantly larger ; the fourth joint has the hind margin somewhat

produced, which is not the case in the first pair ; the fifth has a narrower hind lobe ; the

sixth is oblong oval, the closely- fringed palm more oblique, and subequal to the hind

mai'giu, which carries two groups of spinules. The finger, according to Dana, is " curved

and short, and shuts close against " the palm ; in the Saghalien specimens its outer

margin is strongly convex, and the inner, which matches the palm, carries six minute

setules.

Fencopods. These are moderately stout, tlie finger curved, with the usual setule on

the inner margin. In the last three pairs the second joint is nearly orbicular, with the

hind margin slightly crenulate. In the Saghalien specimens the branchial vesicles are

narrow at the base, then becoming inflated.

Third uropods. These are very short. In the Saghalien specimens the ramus is as

long as the peduncle, each carrying apical spines.

Telson. This is not mentioned by Dana. It is short, divided beyond the middle, but

not to the base, each half as broad as long; the apices are divergent, truncate, tipped

with spinules.

57*

414 EEV. T. E. E. STEBBING ON AMPHIPODA FEOM

Length. " Four lines," about 8 mm. (Dana) ; 5 mm. (Saghalien specimens). Dana

prefixes " Eemale ? " to his description ; but, in my opinion, his description and figures

refer to the male.

Hah. New South Wales, from shallow pools of w^ater along shores of Port Jackson

{Dana) ; Saghalien, 49° 30' N., 142° 8' E, {Andrea, specimens belonging to the Copen-

hagen Museum).

Earn. PHLIADID^.

Antennae short, first pair without accessory flagellum. Upper lip with distal margin

undivided. Lower lip without inner lobes. Mandibles without palp. Eirst maxillfe

with the palp obsolete. Gnathopods simple or only feebly subchelate. Pleopods with

the peduncles laterally produced in one or more of the pairs. Third uropods not

biramous. Telson entire.

( Palp of the maxillipeds three-jointed, 2.

( Palp of the maxillipeds four-jointed, 3.

r Second uropods with two rami PA/zf/.s Giirriu, 1836.

Second uropods with one ramus Pereionotus Bate and Westwood, 1862.

f Third pleopods with rudimentary inner ramus. . . . Iphiplateia n. "■

{;

L Third pleopods with well-developed inner ramus, 4.

st four pairs of side-plates very deep Iphinotus, u. g.

st four pairs of side-plates very shallow JSircmwa Chilton, 188 1.

The genus Iphigeiiia, G. M. Thomson, is represented as having a three-jointed palp to

the maxillipeds, but in other respects its resemblance is so close to Iphinotus that its

right to stand as a separate genus awaits confirmation.

All the genera of this family have representatives in the Southern Ocean ; but

Pereionotus pertains also to English and Mediterranean waters, acd Phlias to the

Mediterranean.

Iphiplateia, n. g.

Body much depressed, pleon strongly flexed. Head immersed between the projecting

side-plates, square, feebly rostrate, with the eyes on the prominent front corners. First

four pairs of side-plates very large, outspread. Antennae short, subequal in length, the

first the broader, the second attached on the under surface of the head, some way to the

rear of the first. Upper lip with entire convex distal margin. Mandibles without palp.

Lower lip without inner lobes. First maxillae without inner plate ; jJalp obsolete, but the

position for it marked ; apical teeth of outer plate five in number. Second maxillae with

the small outer plate continuous with the base, the inner broader. Maxillipeds with

palp extending beyond the outer plate ; the fourth joint small, not unguiform. First

and second gnathopods simple. Third, fourth, and fifth peraeopods with widely-

expanded second joint, and the fourth joint broad. Second and third pleopods with

lateral expansion of the peduncle, the third with rudimentary inner ramus. First and

THE COPENHAGEN MUSEUM AND OTHER SOUECES. 415

second uropods biramoiis, the second smaller than the first ; third uropods one-jointed,

very small. Telson entire.

The name is derived from the prefix (<?(-, signifying strength, and TrAareTa, broad.

Only one species is at present known.

Iphiplateia Whiteleggei, n. sp. (Plato 34.)

The body forms a broad oval ; the basal joint in the first antennse, and the second

joint in the last three pairs of perseopods, helping to complete the figure. It is dorsally

a little convex and smooth, or feebly angiilar along the centre ; the last segment of the

perseon slightly upraised, and the first segment of the small pleon projecting backward

in a prominent tubercle, the remainder of the pleon being rather tightly folded under

the body, its sixth segment dorsally undeveloped. The head is embedded between the

subtriangular first side-plates, which project forward beyond its rounded corners, these

being almost on a level with the short obtuse rostrum. The second side-plates oblong;

the third a little more widened distally ; the fourth very broad, excavate behind ; the

fifth, sixth, and seventh small, bilobed, the front lobe the larger.

The eyes are small, oval, dark, close to the corners of the head.

First mitennce. First joint nearly as broad as long, with large advanced inner lobe ;

second similar in shape, but much smaller ; third narrow, not lobcd ; flagellum very

small, two-jointed, second joint minute.

Second antennce. Basal joints, small, obscure, seemingly soldered to underside of head ;

penultimate joint of peduncle rather larger than ultimate, neither large ; flagellum two-

jointed, small, scarcely so long as last joint of pedimcle, second joint scarcely visible.

Epistome rounded above. On either side of it is a small, rounded oval, pellucid space

in the ventral surface of the head.

Upper lip. At the centre of the margin are two oval spaces, each enclosing a tuft of

short hairs, the two tufts not convergent.

Jlandibles. Cutting-edge quadridentate ; sjiine-row consisting of three minute

spinules ; molar tubercle wanting, unless represented by a broad pellucid spine tipped

with a setule.

First maxillcB. Of the apical spines four form a row, the fifth being set beside them

near the centre.

Second maxillce. Inner plate with truncate apical margin, fringed with five very short

and small but rather broad spines, the innermost the largest ; the outer plate very

narrow, tipped with a few sjoinules. The mandiljles and maxillte are in this genus not

only exceedingly small, but so closely compacted that it is difiicult to sej)arate theiu.

Maxillipeds comparatively wide. Inner plate with four minute spine-teeth on the

truncate apex, outer plate rather broad, the inner margin carrying six widely -sjjaced

insignificant spine-teeth ; first three joints of palp not greatly ditfei'ing in length ; second

much broader than third ; fourth small, cylindrical, and so pellucid that its margins may

easily be mistaken for a couple of seta?, its apex tipped with a very long seta.

First gnatliopods. Second joint not nearly reaching the distal border of the side-plate ;

third as long as fourth, the latter, as usual, underriding the wrist; the wrist or fifth joint

416 EEV. T. E. K. STEBBIXG ON AMPHIPODA FROM

a little longer than the sixth, which narrows to the apex, formiBg no palm; finger small,

curved, with a sctule on the concave margin, near to the nail. The hand and finger

have a closely similar structure in both gnathopods and all five perceopods.

Second gnathopods like the first, except that the fifth and sixth joints are more nearly

equal. Branchial vesicles narrow.

First percBopods. Second and third joints as in the gnathopods ; fourth scarcely longer

than wide, narrow at the base, then widening to a lobe in front ; fifth joint a little shorter

and narrower, as broad as long, much shorter than the sixth.

Second perccopjods like the first.

Third perceopods. Second joint rounded oval, little longer than broad, the hinder

expansion broadly produced below the third joint ; fourth as broad as long, hind lobe well

expanded and produced downward ; fifth much narrower, a little longer than broad,

distally narrowed, shorter than sixth.

Fourth perceopods like the third, but the second and fourth joints larger.

Fifth perceopods. Second joint shorter than in the two preceding pairs, but even wider,

the great hind expansion having a somewhat three-sided margin ; the remaining joints

nearly as in the third ])air.

First p)leopods. Peduncle twice as long as broad, with five or six coupling-spines; rami

with about ten joints, inner ramus the shortei-, with no cleft spines.

Second pleopods. Peduncle nuich shorter, distally widened, so as to be fully as broad

as long, with five or six coupling-spines on the projection ; rami nearly as in first pair.

Third pleopods. Peduncle very short, with a long narrow projection, carrying at its

apex three coupling-spines ; inner ramus minute, oval, unjointed, without setae ; outer

ramus normal, but with the divisions of the joints somewhat obscure.

First iiropods. Peduncle longer than the straight inner, rather shorter than the curved

outer ramus. The rami with obtuse apices, the vis-ii-vis margins microscopically

pectinate, the others finely ciliate.

Second tiropods much smaller than first, otherwise similar.

Third tirojwds consisting of a small oval piece, nearly concealed by the telsou. A

minute setule projects from outer margin of the apex.

Telson semi-oval, with narrow apex projecting beyond the third uropods.

Length about a fifth of an inch, 5 mm.

Sah. Australian waters. Specimens sent me from Watson's Pay, New South Wales,

by Mr. Thomas Whitelegge, who called attention to their peculiar appearance, and in

compliment to whom 1 have named the species.

Pereionotus Bate and Westwood.

1862. Pereionotus Bate and Westwood, British Sessile-eyed Crustacea, vol. i. part 5, p. 226.

1862. „ Bate, Catalogue of the Ampiiipodous Crustacea in the British Museum, p. S"^.

1863. Icriduiin Grube, Sitzungsberichte der Schles. Gesellsch. voni ISteii Februar 1863.

1864. ,, Crube, Archiv fur Naturgeschichte, Jahrg. 30, Bd. i. p. 209.

THE COPENHAGEN MUSEUM AND OTHER SOURCES. 417

1888. Pereionolus Stebbiiig, ' Cliallenger' Amphipoda, pp. 81, 340, 318.

1893. „ Delia Valle, F. u. Fl. G. Neapel. Moii. 20, Gammariui, p. 559.

Body depressed, pleon strongly flexed. Head square, feebly rostrate, with the eyes on

the prominent front corners. Antennae short, the second shorter and much more

slender than the first, attached on the under surface of the head some way to the rear of

the first. Mouth-organs in general like those of Ipliiplateia, the maxillipeds excepted,

in which the palp does not reach beyond the outer plate, and is only three-jointed.

The limbs of the person also nearly as in Iphiplateia, except that the second joint of the

fiftli perseopods is very much smaller than that of the third and fourth pairs. All the

pleopods -with botli rami well developed, tlie peduncle laterally produced in the third

pair or in both the second and third pairs. The first uropods biramous ; the second much

shorter, uniramous ; the third one-jointed, obscure, completely covered by the telson,

which is entire.

The type species, Fereioiiotus testtido (Montagu), seems to be almost certainly

identical with Icridium fuscum Grube, while PliUas serratus Guerin is certainly distinct.

I am indebted to M. Ed. Clievreux for a Mediterranean specimen labelled Icridium

fuscum, but which has the first and second uropods both biramous as in the genus

Phlias of Guerin.

Pereionotus Tuomsoni, n. sp. (Plate 35 A.)

The body is a broad oval. The medio-dorsal line throughout the peraeon and in the

first two segments of the pleon is raised to a carina, formed by a succession of processes

not quite so long as their respective segments, that on the first peraeon-segment being

preceded by an acute point directed forward.

Head. The lateral angles extend a little in advance of the small, but distinct,

rostrum ; and, though on the whole rounded, they have a minutely acute point on tlie

inner side.

The first four pairs of side-plates are without conspicuous setules on the distal margin.

Eyes. Rounded oval, dark, situated on the lateral lobes of the head.

First antennce. Tlie inner margin of the l)road first joint is indentured ; the second

joint cylindrical, not lobed ; the third conical; the flagellum small, two-jointed, with the

long hyaline filaments common to all the species of this family.

Second antennce. Very slender ; the last joint of the peduncle is rather longer than

the penultimate; the flagellum consists of one short joint with several setae about thrice

as long as the joint. On one side of the specimen the flagellum is possibly two-jointed.

Upper lip. The hairs on the distal margin are convergent.

First maxillie. These show a small spinule in the position of the palp. This minute

character may be generic ; but in tlie other species only a sligiit bulge of the margin

has been perceived at the point in question.

Maxillipeds. Inner plates Avith three or four apical spine-teeth ; the outer plates

rather large, minutely fringed on distal half of the inner margin ; palp only three-jointed,

and not quite reaching the ajiex of the outer plate.

418 EEY. T. E. K. STEBBING ON AMPHIPODA FROM

First and second gnathopods and frst and second pertpopods. All these are scarcely

distinguishable from the corresponding limbs in Iphiplateia Whiteleggei. In common

with the three following pairs of perteopods they have on the inner margin of the sixth

joint not only a tolerably strong apical spine, but a similar one nearer the middle.

Third j)er(eopods. The second joint is broader than long, with very convex hind

margin ; the fourth joint is not longer than the third, and is very broad by reason of the

great hind lobe ; the fifth joint is neither so long nor so broad as the third ; the sixth and

the finger are as in the kindred species in general, but the inner setule of the finger

not very strong.

Fourth perceopods. These are like the third, except that the lobe of the fourth joint

is less expanded, and the second joint is smaller.

Fifth perceopods. These are like the fourth, except in regard to the second joint,

which is not only much smaller, but differently shaped, the hinder exjiansion not quite

reaching, instead of overlapping, the third joint

First pleop)ods. Peduncle about twice as long as broad, with two coupling-spines ; the

rami slender, with elongate first joint and six or seven short ones.

Second pleopods. Peduncle broader than long, with two coupling-spines on the convex

but not otherwise projecting inner margin, the rami broader than in the first j)air.

Third pleopods. Peduncle short, with the coupling-spines on a sliort but very

distinctly produced process ; the rami broad, subequal, differing little from those of the

second pair.

First uropods. The peduncle is slightly longer than the longer (probably the outer)

ramus, the other ramus shorter and somewhat curved ; both are narrow, each with a

spinule and short stout spine on the apex.

Second uropods. The peduncle docs not reach the end of the telson ; it has the apex

armed with a spinule and short, stout spine; the narrowly oval, single ramus similarly

armed.

Third uropods. Attached to the ventral plate, which represents the sixth pleon-

segment, are two membranous, rather conical, plates, which together occupy the breadth

of the telson, but do not reach its apex.

Telson. Triangular, with rounded apex.

Length. Less than 5 mm.

Hah. Watson's Bay, Australia. A single specimen, a female with eggs, occurred in

the gathering from low-tide line, obligingly sent me by Mr. Thomas Whitelegge.

The species is remarkably like Pereionotus testudo, as figured by Delia Valle, to whom

I am indebted for a specimen from the Mediterranean. It differs by the absence of the

lateral tubercles on the perseon-segments, the want of any conspicuous setules on the

distal margin of the first four pairs of side-plates, the presence of a submedian spine on

the inner margin of the sixth joint of the limbs, and in having the peduncle of the

second pleopods not outdrawn. The third uropods are obscure in both species, but

api)arently present and similar in both.

THE COPENHAGEN MUSEUM AND OTHER SOURCES. 419'

Iphinotus, n. g.

Body mucli depressed, pleon strongly flexed. Head immersed between the projecting

side-plates, square, feebly rostrate, with the eyes on the prominent front corners. First

four pairs of side-plates very large, outspread. Antennae short, subequal in length, the

first the broader. Uj)per lip Avith the convex distal margin rather flattened. Mouth-

organs in general as in Iphiplateia, the maxillijieds excepted, these having the fourth

joint of the palp well-develoj)ed, unguiform. Tlie limbs of the pera3on nearly as in

Iphiplateia, excej)t that the second and fourth joints in the fifth perseopods are very

much smaller than those in the third and fourth pairs. All the pleopodswith both rami

well developed, the peduncle in the second and third pau-s laterally produced in a long

and strong process. The first uropods slender, the second stout, both biramous, with

the peduncle much longer than the rami. The third uropods 'membi'anous, not

biramous, small. Telson entire.

The name is derived from the prefix (<pi-, and viZroc, back.

Iphinotus Chiltoxi, n. sp. (Plate 35 B.)

The body is broad oval, with dorsal carina, of which the condition of the specimens no

longer allows a minute description.

Head and eyes as in Pereionotiis Thomsoni.

First aiiteinue. First joint large, distally widened ; second cylindrical ; third scarcely

longer than broad; flagelluni of three small joints, with the usual filaments.

Second antennce. Moderately stout ; the last joint of the peduncle longer than the

penultimate ; flagellum of five joints, of which the last four are very small, all setose.

Upper lip. Broader than deep, with converging hairs on the almost straight distal

margin.

Mandibles, lower lip, and. maxillce as in Iphiplateia.

MaxiUipeds. Inner plates with four apical spine-teeth, outer with minute sctules along

inner margin ; jmlp four-jointed, reaching considerably beyond the outer plates ; the

fourth joint unguiform.

First and second gnathopods and first and second pera>opods. These are in general

as in Fereionotus Thomsoni, but the finger is abruptly narrowed at the sharp hooked

nail, and the setule of the inner margin is strong.

Third and fourth perceopods. Second joint very large, only a little longer than broad,

but rather longer in the third pair than in the fourth ; the fourth joint greatly expanded,

the great hind lobe being nearly double the length of the front margin ; fifth joint a little

longer than the third ; sixth joint and finger as in the preceding pairs.

Fifth perceopods. These are much smaller than the third or fourth, especially in regard

to the second and fourth joints ; the second, with its hind expansion, not quite reaching

the third joint ; the hind lobe of the fourth scarcely longer than its front margin.

First pleopods. Peduncle not very long, and not expanded.

Second pleojjods. Peduncle short, but produced on the inner side to a long and

SECOND SERIES. — ZOOLOGY, VOL. VII. 58

420 EEY. T. R. E. STEBBING ON AMPHIPODA FEOM

powerful j)i'ocess, at the truncate apex of which are four coupling-spines ; the rami are

long, of eleven or twelve joints, the outer ramus the longer.

Third pleopods. These closely resemhle the second pair, hnt the process of the

peduncle appears to be a little less massive and the rami appear rather less strong.

First wropods. Peduncle slender, more than twice as long as the slender, sixhequal,

finely ciliated rami.

Second urojwds. Shorter, but much stouter, than the first ; the peduncle about twice as

long as the stumpy rami, and fringed near the outer margin with some eleven short spines.

Third nroimds. Membranous, broad above, but together not so broad as the telson;

the pointed apex projecting just beyond the telson. In the two specimens figured there

is the appearance of a broad basal and a small triangiilar apical joint ; but this may be

due to an accidental folding, as in a third specimen these uropods are single-jointed.

Telson. Much wider than long, membranous, with a few slight setules at the sides ;

the apex slightly angular, the angle very obtuse.

Length. About 5 mm.

Hah. Lyttelton Harbour, New Zealand. Specimens, labelled " Iphiyenia typical'

kindly sent me many years ago by Mr. (now Dr.) Charles Chilton, F.L.S.

In 1882, Mr. G. M. Thomson, F.L.S., in the ' Transactions of the New Zealand Institute,'

vol. xiv. p. 237, established under the family Corophiida? the genus Iphigenia, which he

held to be allied to Iciliiis Dana. He described and figured (pi. 18, fig. 6) the single

species Iphigenia typica, from two specimens obtained by the dredge in Otago Hai'bour,

New Zealand. He gives the length as " 0'12 inch." Upon comparing his description

and figures of this peculiar new form with the specimens sent me by his friend

Mr. Chilton, I did not A^enture to suppose that there could be a question of more than

one sjiecies. Nevertheless, one important feature obviously called for reinark. The

Lyttelton Harbour specimens were provided with a four-jointed palp to the maxillipeds

(see ' Challenger ' Amphipoda, p. 1638) ; while in Mr. Thomson's figure the palp is

three-jointed. As this circiirastance is not referred to either in his generic definition or

description of the species, and as the figure itself is small and not very clearly printed,

there might be some doubt as to what was really intended. But, to make up for the

inadequacy of the printed figures, Mr. Thomson very kindly sent me clear tracings of

the large original drawings of some of them. One tracing shows the palp of the

maxillipeds considerably overlapping the outer plate, but unmistakably consisting of only

three joints. In the accompanying manurcript, full of valuable notes on New Zealand

Amphipoda, after explaining that he no longer possessed any specimens of Ipjhigenia

typica, Mr. Thomson added, " I have a suspicion that the animal is only a young state of

some different form, partly from the apparent absence of one of the thoracic legs and

partly because the uropoda appear to be very incomplete." The apparent incompleteness

of the uropods was no doubt only due to the difficulty of perceiving the membranous

third pair lying closely beneath the telson. As the fifth perteopods are shown in the

figure, the absence of one of the thoracic legs can only have been accidental, nor was

the immaturity of the specimens likely to have affected the number of joints in the

palp of the maxillipeds.

THE COPEXHAGEX MLTSEFM AND OTHEE SOrECES. 421

Accoi'diug to present iufovmation, therefore, it seems proper to j^lace in different

genera the Lyttelton Harbour specimens here described, and the original Iphigeiiia

typica Thomson. It has been earlier jDointed out by von Martens that the name

Iphlgenia is much preoccupied. The new name iphinotus, therefore, will take its place,

should it appear hereafter that the maxillipeds in Thomson's sijecies were really four-

jointed, but accidentally defective. On the other hand, if Thomson's figure show the true

state of the case, -when that is made clear, it will be necessary and time enough to give

his orenus a new name.

But the two species, Iphinotus Chiltoni and Ipliigenia typica are in many points so

closely alike that, while they perhaps belong to different genera, perhaps also they are

but one species. In addition, however, to the recorded difference in the maxillipeds,

there is a difference in the perseojjods, the fourth pair having its second joint subequal to

that in the third pair in the Lyttelton Harbour specimens, but considerably smaller in

those described by Mr. Thomson. Again, the latter are said to have the " telson about

as broad as long, nearly semicircular " ; whereas in the Lyttelton Harbour specimens it is

much broader than long and slightly angular at the apex. Apparently also in the first

described specimen the dorsal line is much more strongly tuberculate. The validity of

all these marks of distinction remains to be determined by future observation.

BiRCENNA Chilton.

1884. Bircenna Chilton, ' Transactions of the New Zealand Institute,' vol. xvi. p. 264-.

Body broad. Head not rostrate. Antennae short, subequal, both pairs very slender ;

second with prominent gland-cone. Mandibles without palp. First maxillae with inner

plate carrying an apical seta, outer plate having eight apical spines ; position of palp

marked, but no trace of palp apparent. Maxillipeds with outer plate not extending

beyond the inner; palp four-jointed, fourth joint small, not unguiform. Eirst and second

gnathopods with the hinder apex of the sixth joint a little 2:)roduced. Pifth perseopods

larger than fourth, fourth than third. Pleopods all biramous, and all with the peduncles

broadly produced laterally. First and second uropods with unequal curved rami. Third

uropods each consisting of an apically bitid plate, not covered by the triangular telson.

This genus, represented by the single New Zealand species, Bircenna fulvus Chilton,

stands apart from the rest of the family by many of its features. Among the less

obvioits are the characters of the first maxilloe and maxillipeds, the first maxillae having

an inner plate, which seems to be \a anting in the other genera, and eight teeth instead of

five on the outer plate, while in the maxillipeds the outer plate does not, as in the other

genera, extend beyond the inner plate. I am indebted to my friend Dr. Chilton for the

opportunity of dissecting a specimen of Bircenna fulvus.

58*

422 REV. T. E. R. STEBBING ON AMPHIPODA FROM

Fam. MELPHIDIPPID^.

Oammarus spinosiis Goes, 1866, transferred to 31elphidippa by Boeck iu 1871, is

•distinct from Gammariis spinosiis Lamarck, 1818. It may now be called Melphidippa

Goesi.

Neohela serrata Stebbing, 1888, should be called Melphidippa serrata.

Fam. GAMMARID^.

Pakacrangonyx, n. g.

All the side-plates shallow. Eyes rudimentary. First antennae longer than the

second, with small accessory flagellum. The pleopods abnormal, having only one ramus.

The third uropods with very small inner ramus. Telson entire.

The type-species is Paracrangonyx compactus (Chilton), 1882, from wells in New

Zealand.

Apocrangonyx, n. g.

Eyes wanting. First antenna? longer than the second, with small accessory flagellum.

The third uropods rudimentary, without rami. Telson entire.

The type-species is Apocrangonyx lucifugus (Hay), 1882, from a well in Illinois.

Hyalellopsis, n. g.

Body smooth. Fourth to sixth pleon-segments very short. AntenniB short, first rather

the longer, with one-jointed accessory flagellum. Fifth pcra^opod short, with very large

second joint. Uropods short, the third uniramous. Telson small, rounded.

The generic name alludes to the likeness between this genus and the Orchestid Syalella

in the caudal part of the animal.

The type-species is Hyalellopsis Czyrnianskii (Dybowsky), 1874, from Lake Baikal.

Gen. Pallasea Bate, 1862.

In this genus I place : — 1. Gammarus asper Dybowsky, 1874, distinct from Gam-

marus asper Dana, 1852, giving it the new name Pallasea Bybotoskii ; 2. P. Beisnerii

(Dybowsky), 1874; 3. P. cancellus (Pallas), 1772; 4 P. Gerstfeldtil Dybowsky, 1874;

5. P. quadrispinosa Sars, 1867 ; 6. P. Kesslerii (Dybowsky), 1874 ; 7. P. baikali, a new

name for Gammarus LovenU DyboAvsky, 1874, which is distinct from Gammarus

Looeni Bruzelius, 1858 ; 8. P. BrandtU (Dybowsky), 1874; 9. P.Grubii (Dybowsky),

1874 ; 10. P. cancelloides (Gerstfeldt), 1858. All these species of Pallasea occur in

Lake Baikal.

THE COPENHAGEN MUSEUM AND OTHER SOUECES. J.23

Paramicrukopus, n. g.

One of the pleon-segments abruptly elevated above the next. Fifth and sixth pleon-

segments very small. Antennae short, the first the longer, with small accessory

flagelluni. Third uropods rudimentary, the rami not very unequal. Telson small.

The species are Panimicrurojnis Sohkii (Dybowsky). 1874, and Paramicrtiropus

Toczaiioioskii (Dybowsky), 187i, lioth from Lake Baikal.

Gen. Gammaeellus Herbst, 1793.

Under the designation Cancer {Gainmarellus) Herbst has grouped a large number of

species, and for some part of the group it seems right that Gammarelliis should be used

as the generic name. The majority of the species are Amphipoda, so that it seems

further not unreasonable to select an amphipod as type of the genus. The first species

in Herbst's list that is an amphipod is the one which he calls Cancer {Gammarellus)

homari. This is a species instituted by Pabricius in 1779. It was called Amatlda

Sabinil by Bate in 18G2 ; but the name Amathia, due to Rathke in 1837, having been

preoccupied by Lamarck in 1812, Bate and Westwood altered the generic term to

Atnathillu. Spence Bate, however, had previously called the young form of the above-

mentioned species Gi'aijia hnbricata, so that Gnnj'ia has precedence of Amathilla.

:Since a change, then, in any case is necessary, the opportunity is favourable for restoring

Herbst's Gammarellus, and there is an additional advantage in that we are thus enabled

to dispense both Avitli Grayia, which is inconveniently similar to the name of a reptilian

genus, Grrtirt Giinthcr, 1858, and ^'\\\\ Amathilla, which is equally near to the molluscan

name Amathella Gray, 1859.

The two species coming under this revived generic name are Gammarellus homari

(Fabricius), 1779, and Gammarellus angulosus (Eathke), 1843. A third nominal species,

Gammarellus carinatus (Bathke), is not certainly distinct from G. homari.

EUCRANGONTX, n. g.

Like Craugonyx in general, but with a small inner ramus to the third uropods. Telson

emarginate.

The species assigned to this genus are: — 1. Eucrangonyx mucronatus (Forbes), 1876;

2. En. Vejdovskyi, a new name for Crango)iyx suhterranem Vejdovsky, 1896, which

seems to me distinct from the sjiecies so named by Bate in 1859 ; 3. Eu. Packardii

(Smith), 1888 ; 4. Eu. gracilis (Smith), 1871 ; 5. En. antennahis (Packard), 1881.

Eu. gracilis is from Lake Superior and Lake Huron, the others from wells or svib-

terranean streams.

Gen. AxELBOECKiA, n. n.

The name is proposed as a substitute for Btoeckia Sars, 1894, preoccupied by Malm in

1870, and by G. S. Brady in 1871.

424 EEV. T. E. E. STEBBING ON AMPHIPODA FROM

The generic name is given in honour of the late Axel Boeck, a distinguished

carcinologist.

The siDBcies assigned to this genus are AxeJhoeckia sjnnosa (Sars), 189 i, from the

Caspian Sea, and Axelboeckia Carpenterii (Dyhowsky), 1874, from Lake Baikal.

Brachturoptjs, n. g.

With median rostrate carina. Fourth side-plate with projecting tooth. Pirst antennae

much the longer, with long, accessory flagellum. First and second gnathopods similar,

subchelate. Last three perteopods elongate. First and second uropods elongate, third

rudimentary, with very iinequal rami. Telson apically emarginate.

The generic name alludes to the shortness of the third uropods.

The species included are Brachyuropns Greioingldi (Dyhowsky), 1874, and Brachy-

uropus Beichertii (Dyhowsky), 1874, hoth from Lake Baikal.

Gen. Brandtia Bate, 1862.

In addition to the type-species Brandtia latissima (Gerstfeldt), 1858, there may be

referred to this genus : — 2. B. lata (Dyhowsky), 1874 ; 3. B. tuhercnlata (Dyhowsky),

1874; 4. B. Moratvifzii (Dyhowsky), 1874; 5. B. smaragdina (Dyhowsky), 1874; 6. B.

fasciata, a new name for Gammarns zehraDyhowsky , 1874, which is distinct from

G-. zebra Rathke, 1843. All these species occur in Lake Baikal.

MiCRUEOPUS, n. g.

Without carime or overarchiug segments. Antenna; short, with subequal peduncles,

the first pair usually longer than the second ; accessory flagellum one-jointed. First

and second gnathopods with subequal hands. Third lu'opods small or very small ; the

rami unequal ; outer ramus usually one-jointed. Telson cleft.

The generic name refers to the smallness of the third uropods.

The species referred to this genus are : — 1. Illcruropus puella (Dyhowsky), 1874 ;

2. M. inflatus (Dyhowsky), 1874; 3. M. rortex (Dyhowsky), 1874; 4. M. talitroides

(Dyhowsky), 1874 ; 5. i¥. Z/^/oraZis (Dyhowsky), 1874 ; 6. Jf. ^Zaier (Dyhowsky), 1874 ;

7. M. rugosus (Dyhowsky), 1874; 8. 31. Wahlil (Dyhowsky), 1874; 9. M. Fixsenii

(Dyhowsky), 1874; 10. M. perla (Dyhowsky), 1874; 11. M. Khikii (Dyhowsky), 1874;

12. M. pachytus (Dyhowsky), 1874. All from Lake Baikal.

Neoniphaegus, n. g.

First to fourth side-plates much deeper than those which follow. Eyes weD developed

(or wanting). First antennae the longer; accessory flagellum very small, two-jointed.

Mouth-parts nearly as in Niphargus (but first maxillae in the type-species said to have

six instead of seven spines on the outer plate). First and second gnathopods similar^

THE COPEXHAQEX MUSEUJSI AND OTHER SOURCES. 425

subchelate ; fifth joint distally wide, sixth subquadrate. Pifth perieopods shorter than

fourth. Third uropods not elongate ; outer ramus one-jointed, inner minute. Telson

partly (or wholly) cleft.

The type-species is Neoniphargus Thomsonl, a new name for Mr. G. M. Thomson's

Niphargus montanus, 1893, from Mount Wellington, in Tasmania. As Costa's Gammarus

montanus, 1857, appears to be a Niphargus, the name used by Thomson was pre-

occvipied. A second sjiecies, doubtfully assigned to this new genus, is the Gammarus

puteanns of Moniez, 1889, from subterranean waters in Prance. It was renamed

Nij^hargus Moniezi by Wrzesniowski in 1890.

Hakonboeckia, n. g.

Near to AxelboecMa and Gmelinopsis. Segments of peraeon with margins acutely

produced. Head with rostral and lateral projections. Antennye with equal peduncles,

first pair the longer ; accessory flagellum very small. Hand of first gnathopods lilie that

of second, but larger. Third to fifth perseopods with the second joint broad, not pro-

duced downward. Third urojiods with subequal rami, the outer ramus (seemingly) one-

jointed. Telson cleft nearly to base.

The generic name is given in compliment to Hakou Boeck, who edited his brother's

well-known woi'k on the Aniphipoda of the North.

The type-species is Hahonhoeckia Strauchii (Dybowsky), 1874, from Lake Baikal.

Baikalogammaetjs, n. g.

Near to Gammarus. Pleon-segments, from the second, third, or fourth to the sixth,

with a few dorsal setules or spinulos. Pirst tmtennae longer than second, but with a

shorter peduncle ; accessory flagellum very short. Hand of first gnathopods not smaller

than that of second. In third to fifth pertpo^wds the second joint broad, the wing pro-

duced downward in a long rounded lobe. Third lu'opods rather elongate ; the peduncle

as long as the two-jointed outer ramus. Telson cleft.

The generic name alludes to Lake Baikal, so prolific in Gammaridae.

The type-species is Balkalogammarus pullas (Dybowsky), 1874, from Lake Baikal.

Gen. Melita Leach, 1814.

Besides the accepted species of this genus, there may be referred to it with more or less

probability Maera conferticola Stimpson, 1857; Ampjhltoe Gayi Nicolet, 1849; and

Gammarus tenuicornis Stimpson, 1856.

Stimpson's Chinese species may or may not be the same as Dana's Melita tenuicornis,

1852, from New Zealand. Dana's 31. tenuicornis is a synonym of his own Melita uicequi-

sti/lis ; but it will be time enough to consider what should be the designation of

Stimpson's species when its distinctness has been proved.

426 EEV. T. R. E. STEBBING ON AMPHIPODA FKOM

Paraceradocus, n. g.

Side-plates not deep, the first larger than the fourth. Eirst antennte longer, but not

stouter than the second, and with shorter peduncle. Upper lip transversely elliptic.

Under lip with principal lobes dehiscent. Palp of mandibles elongate ; third joint not

short. First maxillge with large inner plate, carrying setae only on the apex ; the palp

broad. Second masilloe having tlie inner plate fringed along inner margin. Limbs of

perseon, uropods, and telson as in Ceradocns.

The type-species is Faraceradociis IliersU (Pfeffer), 1888, from South Georgia.

Gen. Ceradocus Costa, 1853.

The species belonging to this genus are : — 1. Ceradocus orchestiipes A. Costa, 1853,

which includes the preoccupied Gammarus fasciatus O. G. Costa, 1844 ; 2. Ceradocus

Torelli (Goes), 1866 ; 3. Ceradocus ruhro-macidatus (Stimpson), 1856 ; 4. Ceradocus

semiserratus (Bate), 1862 ; of which the first and last are both named Ceradocus

fasciatus by Professor Delia Valle.

Gen. Maera Leach, 1814.

In this genus I propose the name Ilaera Westwoodi for Gammarus Kroyeri Bell and

Westwood, 1855, Avhicli is distinct from the earlier Gammarus Kroyeri Rathke, 1843,

and add to tlie accepted species Ilaswell's Megamoera 3Iastersii, 1880; Dana's Gam-

marus asper, 1852 ; his Gammarus ? indicus, 1853 ; Gerstfeldt's Gammarus kilrgeusis,

1858 ; and Dana's Amphithoe puhescens, 1852. The last four are involved in some

obscurity.

Gen. ElasmopUvS A. Costa, 1853.

To the sjiecies already accepted in this genus may be added Haswell's Megamoera

suensis, 1880 ; his Iloera viridis, 1880 ; his Megamoera Boeckii, 1880 ; the Moera crassi'

mana of Miers, 1884, the specific name becoming crassimanus ; and the Maera Miersi of

Wrzesniowski, 1879. The last two are rather obscure.

Plesiogammarus, n. g.

Near to Gammarus. Many of the segments have a marginal swelling. The pleon

carries dorsal setae, but no dorsal spines. Peduncle of first antennae longer than that of

second. Third to fifth peraeopods with the second joint long and narrow. First uropods

reaching to the end of the short third pair. Telson not cleft to the base.

The type-species is Plesiogammarus Gerstaeckeri (Dybowsky), 1874, from Lake

Baikal.

THE COPENHAGEN MUSEUM AND OTHEK SOUKCES. 427

Phreatogamjiarus, n. g.

Without eyes. Upper lip broader than deep. First joint of mandibular palp not

very short. Pirst and second gnathopods equal. First and second perfeopods much

shorter than third. Fifth peroeopods the longest, with sixth joint much longer than any

of the other joints. Thii'd uropods long, with equal, one- jointed, cylindrical rami.

Otherwise like Gammarus.

The generic name means a well- Gammarus.

The type-species is Phreatogammarus fragilis (Chilton), 1882, from wells in New

Zealand.

Ommatogammartjs, n. g.

Near to Gammarus. Dorsal spines only on fourth to sixth pleon-segments. Eyes of

irregular form, with indented outline. First antennfe longer than second, but usually

with shorter peduncle; accessory flagellum of more than one joint. Upper lip narrowed

to a rounded apex. Under lip with inner lobes i-udimentary. Third joint of mandibular

palp not very elongate. First maxillse having inner plate fringed with numerous sette,

outer carrying eleven spines ; second joint of palp with about ten spine-teeth on one

maxilla, and short spines on the other. Maxillipeds with outer plate reaching far along

second joint of palp ; spine-teeth and setae numerous. Hand of iirst gnathopods not

smaller than that of second. Third uropods having outer ramus about twice as long as

inner, with simple setse on its inner margin ; inner ramus with feathei'ed setse on both

margins. Telson cleft to the base.

The generic name alludes to curious character of the eyes.

The species included are : — Ommwto^amwzarM^ ff/6^»«s (Dybowsky), 1874 ; 2. O.Jlacus

(Dybowsky), 1874 ; 3. O. carneolus (Dybowsky), 1871 ; 1. 0. amethysfimts (Dybowsky),

1874 ; all from Lake Baikal.

Odontogammarls, n. g.

In general like Gammarus, but lower front angle of fifth side-plates produced into a

tooth ; jieduncle of first antennse not shorter than that of second, its third joint as long

as its second ; hand of first gnathopods not smaller than that of second ; third to fifth

perseopods having second joint produced at lower hind angle into a tooth ; third uropods

not very long, but, as in Gammarus, the tAvo-joiuted outer ramus longer than the inner.

The generic name alludes to the tooth on the fifth side-jilates.

The species included are Odontogammariis calcaratus (Dybowsky), 1874, and 0. mar-

garitaceus (Dybowsky), 1874, both from Lake Baikal.

SECOND SERIES. — ZOOLOGY, VOL. VII. 59

428 EEV. T. E. R. STEBBINa ON AMPHIPODA TKOM

DiKEROGAMMARUS, n. g.

Pourth and fifth pleon-segments each raised dorsally to a spiniferous tuhercle. First

antennae the louger; accessory flagellum well developed. The gnathopods larger in the

male than in the female ; the second larger than the first. The form agrees in general

with Gmmnarus.

The generic name alludes to the two horn-like elevations on the pleon.

The species included are : — Bilierogmnmurus macrocephalus (Sars), 1896 ; 2. D. hcemo-

baphes (Eichwald), 1842 ; 3. B. Grimmi (Sars), 1896 ; 4. B. Verreauxii (Bate), 1862 ;

5. D.fasciatus (Say), 1818. The first three are found in the Caspian, the fifth in streams

and ponds of the United States of America. The fourth is said to have been found by

M. Verreaux in New Holland, Spence Bate ascribing the species to " Edwards, Ann. des

Sc. Nat.," a vague reference which has not yet been verified.

Gen. Gammaeus J. C. Fabricius, 1775.

For Gammarus tenellus Sars, 1896, which is distinct from Gammarus tenellus Dana,

1852, I propose the equivalent name G. ischims. For G. marimis Risso, 1826, which is

distinct from G. viarinus Leach, 1815, it is useless to propose a wqw name while the

species remains unidentilied.

PffiKILOGAMMARUS, U. g.

All segments of perseon and pleon usually having dorsal hairs or spinules. Head

rostrate. First antenme with peduncle longer tlian that of the second pair, its tliird

joint longer than the second. Upper lip with wide, almost straight, apical margin.

Under lip, as in AccelboecMa, having the principal lobes separated by what may be rudi-

mentary inner lobes. First maxillae with about six sette on the inner plate. Outer

plate of maxillipeds not reaching far along the second joint of the j)alp. Hand of first

gnathopods larger than that of second. Third uropods with equal i-ami, both carrying

plumose setae ; outer ramus one-jointed. General character like Gammarus.

The generic name alludes to the variegated colouring of the several species.

The species included are : — Pcekilogammariis pictus (Dybowsky), 1874 ; 2. F. orchestes

(Dybowsky), 1874; 3. P. talUnts (Dybowsky), 1874; 4. P. araneolus (Dybowsky),

1874 ; all from Lake Baikal.

ECHINOGAMMARUS, n. g.

In general like Gammarus, but with dorsal spines on segments anterior to the fourth

of the pleon ; the first antennae longer than the second, though with shorter peduncle ;

the hand of the first gnathopods almost always larger than that of the second.

The generic name alludes to the numerous spines on the body.

THE COPENHAGEN MUSEUM AND OTHER SOUECES. 429

The species included are : — 1. Echinogammarus Berilloni (Catta), 1875, in certain

fresh waters of Western Europe ; 2. K cevrucosus (Gerstfeldt), 1858 ; 3. E. Maackli

(Gerstfeldt), 1858 ; 4. E. ocJiotensis (Brandt), 1851, from Ochotsk Bay; and the

following tw^enty-three, all instituted under the generic name Gammarus by Dybowsky

in 1874, and all, like the second and third, found in Lake Baikal : — saphirinus, Czerskii,

lividus, viridis, cyaneus, testaceus, Sophice, fuscus, murinus, aheneus, sarmatus, capreoltis,

TJzzolzewii, stenophtJialmm, schamanensis, leptocerus, toxophthahnus, vittatns, Fetersii,

violaceus, ibex, ParvexU, poI[farthn(s. Here, too, may perhaps be placed the obscure

Gammarus mut'Uus of Abildgaard, 1789.

Heterogammarus, n. g.

In general like Gammarus, without dorsal teeth or carinse or noticeable processes of

head- or side-plates ; accessory flagellum of first antennae more than one-jointed ; oviter

ramus of third uropods two-jointed ; )mt separated from Gammarus by one or more of the

following characters : — the peduncle of first antennae longer than that of the second ; the

hand of the first gnathopods larger than that of the second; the first uropods very

short.

The generic name alludes to the character of the genus as a second self to Gammarus.

The species included are the following eight, from Lake Baikal, instituted by

Dybowsky in 1874, imder the generic name Gammarus : — Stanlslavii, Sophiaiiosii,

capellus, ignotus, Flori, bifasciatus, branchialis, and albulus ; the last being given by

Dybowsky as a var. albula of Gammarus Florl.

Parapallasea, n. g.

Median carina not represented on peraeon or first to third segments of pleon. Fourth

side-plates broader and not less deep than the preceding, emarginate behind. Flagellum

of first antennae longer than the peduncle ; accessory flagellum elongate. Third to fifth

peraeopods Avith second joint expanded. Telsou deeply cleft. Other characters agreeing

with Palhuea.

Tlie species included are : — 1. Parapallasea Eo7'otoski i {Dyhowsky), 1874; 2. P. La-

gowsk'u (Dybowsky), 1874; 3. P. PuzijlUi (Dybowsky), 1874; all from Lake Baikal.

Carinogammaeus, n. g.

Distinguished from Gammarus by having carinate segments, the carina medio-dorsal

only ; relative proportions of the peduncles in the two pairs of anteuntie, of the two pairs

of gnathopods, and of the inner and outer ramus of the third uropods, variable.

The species included are: — 1. Carinogammarus cimiamomeus (Dybowsky), 1874 ;

2. C. IVagll (Dybowsky), 1874; 3. C. pulchellus (Dybowsky), 1874; 4. C. Seidlitzii

(Dybowsky), 1874 ; 5. C. rhodophthalmus (Dybowsky), 1874— all these five from Lake

430 EEV. T. R. R. STEBBING ON AMPHIPODA FROM

Baikal; 6. C. caspius (Pallas), 1771, from the Caspian Sea; 7. C. atchensis (Brandt),

1851, from Isle of Atcha and Unalaschka ; 8. C. subcarinatus (Bate), ].862, from

Bering Strait ; 9. C. fluviatUis (Bosel), 1755, from rivers and ponds of Europe. To

these may be added, though with some doubt, C. macrophthalmus (Stimpson), 1853, fi-om

Grand Manan ; and C. mucronatus (Say), 1818, from Florida.

ACANTHOGAMMAEUS, n. g.

Body with median, more or less dentate, carina, and also lateral or marginal carinse

more or less developed. Head with very short rostrum. Fiftli side-plates much

shallower than fourth. First antennae the longer ; accessory flagellum iisually much

developed, always with more than one joint. Third and foiu*th perteopods with second

joint narrowed below. Third uropods with rami subequal, not foliaceous. Telson deeply

cleft.

The generic name alludes to the dentate caringe.

The species included are the following six from Lake Baikal, all instituted under the

generic name Gammarus by Dybowsky in 1874: — Cabanisii, Zienkoioiezii, Godlewskii,

Hodoszkoioskii, armatus, and parasiticKS.

EXPLANATION OF THE PLATES.

n.s., natural size.

a.s., iipper antenna ; a.i., lower antenna.

I.S., upper lip ; l.i., lower lip.

m., mandible; mx. \, 2, first and second maxillie ; map., maxillipeds.

gn. ], 2, first and second gnatliopods.

prp. 1-5, first to the fifth peraeopods.

jilp. \, 2, 3, first, second, and third pleopods.

ur. 1, 2, 3, first, second, and third uropods.

T., telson.

Plate 30.

A. Talorcliestia Deshnyesii (Audouin).

The central figure is a lateral view of a young male specimen. The two gnathopods and second and

fifth perseopods are shown separately, magnified to the same scale, with parts oi: each more highly

magnified.

B. Talorchestia tridentata, n. sp.

The first and second gnathopods, and second and third perseopods, are magnified to the same scale, the

inner surface of the hand of the second gnathopods being shown separately ; parts of the three

other limbs are more highly magnified.

THE COPENITAGE^" MUSEUM AND OTHER SOURCES. 431

C. Orcheslia Snlensoni, n. sp.

Parts of tlie first and second giiathopods and of the second perseopod, and tlie whole of tlie third nropod,

are more highly magnified than the rest of the figures, whieh are all drawn to the same scale.

Plate 31.

A. Talorchestia novcf-hoUandm, n. sp.

Parts of the first and second gnathopods of both male and female, and of the second peraeopod, and the

whole of the telson, are more liighly magnified than the rest of the figures.

B. Hijale Guktteoe, n. sp.

The first gnathopod, the third iiropod, and the telson are more liighly magnified, as well as drawn to

the same scale as the other figures.

C. Hijale d'iplodaciyhts, n. sp.

Parts of the first and second gnathopods of the male, and the second gnathopod of the female, with the

whole of the third uropod and the telson, are shown on a higher scale of magnification than that of

the figures in general.

D. Hyale mucruducti/his, n. sp.

Parts of the two gnathopods and the second and fifth pcrEeopods are more highly magnified than the

complete figures of the same limbs.

Plate 32.

A. Hijalelhi JVariniiigi, n. sp.

The antennse, limbs, uropods, and telson are drawn to the same scale, while more highly magnified

figures are given of the mouth-organs, of parts of the first and second gnathopods of the male, and

second gnathopod of the female, of the tiiird uropod and the telson. pl.seym. 3 shows the side of

the third pleon-segment.

B. Hyalella Mctncrti, n. sp.

Both gnathopods of both sexes, and the telson and third uropods, are shown on a higher scale of

magnification.

C. Hijult luaroubrce, u. sp.

Parts of the two gnathopods, of the second and fifth peraeopods, the second and third uropods, and the

telson are more highly magnified, and the apical spines of the sixth joint in the peraeopods are

sIkjwu on a still higher, or third, scale of inagnification.

Plate 33.

A. Allorchesles malleolus, n. sp.

Parts of the gnathopods of both sexes, the telson of the male in dorsal view, the third uropod and

telson of the female in lateral view, are more highly magnified than the parts represented in the

other figures.

B. Allorchesles comp7-essus Dana.

Parts of the first gnathopod of the male, and the first and second gnathopods of the female, are more

highly magnified.

SECOND SERIES. — ZOOLOGY, VOL. VII. 60

432 ON AMPHIPODA FEOM THE COPENHAGEN MUSEUM.

C. Allorchestes plumicornis (Heller),

Part of the first gnatliopod is more highly magnified than the other appendages here figured.

D. Allorchestes humilis Dana.

Parts of the two antennae, of the two gnathopods, the third uropod and the tclson, are shown on the

higher scale of magnification, on which also the two maxillae are drawn.

Plate 34.

Iphiplateia Wliiteleggei, n. sp.

The central fifure at the top of the plate is the animal in dorsal view. The separated head, antcnnse,

and appendages of the pera?on and pleon are more liighly magnified. The minute mouth-organs

and the third uropods are magnified on a still higher scale, and some of the details of the mouth-

organs arc still more enlarged.

Plate 35.

A. Pereionotus Tliomsoni, n. sp.

D., dorsal view of first five peraeon-segments, with the third perseopods.

L., lateral view of the same segments.

The separated head and antennse, the maxillipeds, second maxilla, and appendages of perreon and pleon,

are more highly magnified, all on the same scale. Part of the maxillipeds, the second maxilla, the

uropods and tclson are also given on a higher scale.

B, Iphinotus Chilioni, n. sp.

Part of the maxillipeds is more highly magnified than the other figures. Ur. V , 2', 3', and T', are drawn

from a different specimen from that whicli furuished the other figures.

^bbm^

Trans. Linn, Soc.ZooL Ser. 2. Vol Vll, PI 30,

A

C^.s^

Del T R R StBbb.i>^.

.ITRpnme Ro.J, Llth Bclm'

A. Talorchestia Deshayesii (AUDOUIN).

B.TaLORCHEST[A TRIDENTATA, n. sp. C. ORCHESTIA SULENSONK n.sp

Stebbm^.

A.

Trans. Linn. Soc. Zool. Ser. 2 Vol. Vll, PI, 31,

,fe . 1 S

Del T R R Slsbbini

A. TaLORCHESTIA novae -HOLLANDTAE, n sp.

C. HYALE DIPLODACTYLUS. n sp

.iTRfcdiiie Kpid, I.it}i Kin'"

B. HyALE GALATEAE, n sp

Ii. HY.-.LE MACRODAGTYLUS, n sp

Trans. Linn. Soc.ZooL Ser. 2. Vol VII. PI. 32.

J.TRenmc Kcid, Litli Edir

A. Hyalella Warmingi. n. sp B. Hyalella Meinerti, n. ,sp.

G. HyALE MAROUBRAE, n. ap.

Stebbm^.

Trans. Linn. Soc.Zool. Ser. 2. Vol W, PI.

Del T R. R. St.ebbm^

J.TS«..o.t keid, l.ih- Ein

A. ALLORCHESTES 1-1ALLK0LUS. n ap.

C. ALLORCHESTES PLUMIGORNIS (HELLER).

B. ALLORCHESTES OOMPRESSUS DaNA.

D. ALLORCHESTES riULilLIS DaMA

SLebbmg.

Trans. Linn, Soc Zool. Ser. 2 Vol Vll, PI. 34.

^,

prp, ?..

D-l T ft R Stebbm^

JTh;.inie Reio. Lah tii:^'

IPHIPLATEJA WHITELEGGEI, n. sp.

Trans Linn SocZool- lSer. 2.Vol.\^I, PI. 35.

^.1.

pip

mB^'-

J

M \

prp S. ^^

pip ?.-

D5I T R B Subbing

JT?.et.nie Reid Li;K Edin

A. PEKEIOMOTUS ThOMSONI. n. ST

B. IPHINOTUS ChILTONI. n SD

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[VOL. VII. PART 9.

THE

TRANSACTIONS

OP

THE LINNEAN SOCIETY OF LONDON.

ON FOSSIL AND RECENT LAGOMORPHA.

BY

C. I. FOPtSYTH MAJOR, M.D.

[Communicated by Prof. G. B. Howes, Sec. Linn. Soc.)

^LONDON:

PRINTEl) FOR THE LINNEAN SOCIETY

liY lAYI.OR AND FRANCIS, RED LION COURT, FLEET STREET.

SOLD AT THE society's APARTMENTS, BURLINGTON-UOUSB, PICCAL-ILLY. W.

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

November 1899.

[ 433 ]

AUG 10 1900

IX. 071 Fossil and Recent Lagomorpha. By C. I. Forsyth Major, M.D.

[Communicated hy Prof. G. B. Howes, ^ec. Linn. Soc.)

(Plates 36-39.)

Head 16th June, 1898.

Tooth-change and Tooth-formula in the Lagomyid.e.

1 HE three extinct Lagomyidoe, Titanomys, Prolagus, and Lagopsis, and the surviving

Lagomys, have five nppev cheek-teeth, as against six in Leporidfe [Palceolagus and

Lepus s. 1.). From a comparison of the form and relative size of the teeth in Lepus and

Lagomys, the type genera of l)otli groups, Waterhouse * and Gervais f had rightly argued

that the last uj^per molar of Lagomys corresponds to the penultimate upper molar in the

Hare. Since Lepus changes the three anterior of the upper six, and the two anterior of

the lower five cheek-teeth, the formula heing therefore P.^, M.^, it might have been

further inferred that the number of premolars in Lagomyidae is the same as in the

Lejioridfe.

Curiously enough, in recent species of Lagomys the tooth-change has never been

examined. In 1870 J, O. Fraas described and figured the milk-dentition of Prolagus,

with J cheek-teeth, there being three deciduous molars above and two below. The

obvious inference is that the premolars are the same in number as the milk-teeth, and

therefore in agreement with what is known iu Lepus.

Fraas, however, proposes quite a novel definition of what we have to consider to be

premolars, with the vmavoidable result of thus introducing an element of confusion.

Finding the three upper posterior and the three lower posterior cheek-teeth of Prolagus

more ia agreement as to general form with each other than with those anterior to them,

which are two in the ujiper and one in the lower jaw, he concludes that these last are to be

considered as premolars. According to this theory, which conflicts with the prior state-

ment of the number of deciduous teeth, the tooth-formula would be P. ^, M. tt. But

this second statement is again in flagrant contradiction with the following description of

the mode in which the tooth-change is supposed to occur. The anterior upper premolar,

termed P.^ by Fraas, is stated to have no deciduous predecessor, the place of the anterior

of the three deciduous teeth being taken by the premolar following behind the first, the so-

called P-i ; while the anterior premolar pierces the jaw in front of P.j and comes in place

* Ci. E. Waterhouse, ' A Natural History of the ilammalia," vol. ii. p. 14 (1848).

t Zool. et Pal. Fraae., sec. ed. pp. 48, 49 (1859).

t Wiirttemb. naturw. Jahresh. xxvi. p. 169 (1S70).

SECOND SERIES. — ZOOLOGY, VOL. VII. 61

434 BE. C. I. rOESTTH MAJOR OX

through the same lacuna (" Zahnliicke "), produced by the dropping out of the first

deciduous. The two posterior deciduous teeth are, according to the writer, situated on

the top of molars I. and II. (!) respectively, like so many caps. So that, according- to this

description, of the five upper cheek-teeth of Frolagns, the tirst and the last liave no

deciduous predecessors, hut the three intermediate have. In the lower jaw Praas finds

two deciduous cheek-teeth : " Neben dem ersten zweiwurzeligen Deciduus, der iiber dem

eiuzigen Praemolaren sitzt, ist noch ein zweiter zweiwurzeliger Deciduus, der von dem

ersten Molaren verdrangt wird." According to this, iu the lower jaw the supposed

unique jiremolar and what he believes to be the first true molar Avould have deciduous

predecessors.

Those astounding views necessarily created a distrust in Fraas' description of tj deciduous

molars (in Prolagus) ; and as a consequence most of the subsequent authors on the

subject, up to this day, have, with regard to the Lagomyidaj, preferred to adhere to the

old Cuvierian dictum, viz., that in all the Ilodents with more than three molars, only

the one (or more) anterior to the three ai'e replaced, and that the latter alone are to be

considered true molars.

Eilhol has observed the two anterior lower cheek-teeth to change in Tifuuovtijs, and he

apparently extends this observation to the maxillary teeth as well : " Chez le Titanomys,

les deux premieres dents ^taient sujettes au remplacement " *.

The one author who first rightly interpreted the tooth-formula of Lagomyidae is Winge,

although he has not seen the tooth-change. Of Fraas' statements he says that they are

not clear, partly due to some of the premolars l)eing called molars ; and he continues to say

that Lagumys — which, according to him, includes the fossil " Jli/olagiis" and its allies —

"has^ orT cheek-teeth; these are the ~ ,- , 't ,. „ or "..,'- ,. of the tvpical ~, as is seen

from a comparison with Lcqms ; in the maxillary the three anterior teeth, in the mandible

the two anterior are changed " t-

In the first part of his memoir on Tertiary Eodentia, Schlosser speaks invariably of

only one inferior premolar and of a fourth inferior true molar (m. 4) in fossil Lagoinyidye J .

but later on he gradually § arrives at the true statement of things as given in the

supplement to the above memoir, in the following words : — " In this group (/. e. the

Lagomorpha) at least the first two anterior teeth in each jaw are changed, so that we

must speak of two, respectively three premolars " 1].

My own observations are to the following effect : —

1. Titanohnjs. — This genus has five cheek-teeth in the upper jaw. The deciduous

teeth arc three in the maxillary and two in the mandible, as is seen in the llott skeleton

described belo^v. The two deciduous inferior teeth, as mentioned above, have already

been figured by Filhol %.

* Ann. Sc. Gool. X. p. 29 (1879).

t " Om ruttcdyrenes Tandskifte " ( Yideusk. Meddcl. Natiirh. Toreuing i Kjiibenliavu f. 1882), p. 48 (1883). Sec

also H. AViugc, iu ' E Museo Lundii,' i. pp. 11)8, 111 (1S88).

% ' Pala-'outographica," xxxi. p. 10 &c. (1884). § Op. cit. p. 110, Anm. 2.

l| Palwontogr. xxxi. p 327 (1SS5). f Oj>. cit. p. 20, pi. 3. fig. 3.

FOSSIL AND EECENT LAGOMORPHA. 435

As to the number of lower clieek-teeth, I find, as a rule, five in one of the species,

Tilanomys Fontannesi; but in two out of seventeen mandibular rami there are only

four teeth, there being no trace of an alveolus for the last small tooth, which probably

will be found constantly present in young specimens.

In the other species, T. visenooiensis, the fifth lower molar is supposed to be oftener

missing than not. Pomel called Ampliilagus — regarded by him as a subgenus of

Lacjomiis — those specimens of T. viseuoviensis in which fi.ve mandibular cheek-teetii

were present ; those with only four teeth he placed in his genus Lagodus [Lagodits

picoides, Vomc\, = T'danomys visenomemis, H. v. Mey.). Eilhol has based a fusion theory

on the presence or absence of the small molar in question *. He assumes that at a certain

given moment there prevails a tendency to simplification in the Lagomyine dentition —

firstly by the fusion of the last (fifth) tooth with the penultimate, and secondly by the

tendency of the fused elements to disappear.

This theory is at once disposed of by the fact that in the mandibles of Titanomijs

Fontannesi. before me both the fifth tooth and the posterior colonnette of the fourth —

which colonnette Filhol considers to be the fifth tooth fused to the fourth — are present

togetlier. I think that for T. visenovleusis the same explanation holds good as with

regard to T. Fontannesi, viz. tlie fifth tooth has sometimes been lost in the young animal

and its alveolu.s obliterated ; its frequent absence is simply explained by the fact that it

has dropped out in the fossils.

Anyhow, the formula of Titanonii/s will have to be written as follows : —

P.!!,M. A, or i'-^'P-'P-'="-'-™--

2' "-"• 2—3' "" p. 2, p. 1 ; m. 1, m. 2 (m. 3)'

2. Prolagvs. — I have at my disposal the deciduous molars of two species of Prolagus

[P. fpningensis (Kon.) and P. sardus (Wagn.)]; there are three in the upper and two in

the lower jaw, as seen already by Fraas in the first-named species. In the skull of a

young P. sardus, where the deciduous teeth are in situ, the following may be seen : — The

anterior of the three deciduous teeth is not situated directly above the anterior premolar,

but slightly backward, closely appressed to the second deciduous, so that with its anterior

moiety it covers only the posterior part of the premolar ; besides it could not possiblv cover

the latter completely, being much smaller. It is needless to say that neither of the true

molars, both of which are already protruded in the skull under observation, supports a

milk-tooth ; as a matter of fact, the tooth called molar I. by Fraas, which in reality is the

posterior of the three premolars, is situated under the posterior of the three deciduous

molars, as is the middle premolar imder the middle deciduous.

In the lower jaw of both species the two anterior of the four lower cheek-teeth replace

the two deciduous teeth.

Therefore, since Prolagus has in the full-grown animal five cheek-teeth above and

four below, its tooth-formula will be : —

P. ■', M. :-, or P-^-P-^-P-|='"-i-"^-^.

- 2 p. 2, p. i ; m. 1, m. •!

* Aun. Se. Geol. x. p. 28 (1870).

61*

436 BE. C. I. FOKSYTH MAJOK ON

3 & 4. Lagopsis and Lagomi/s. — Since these genera have five cheek-teeth in both jaws,

there being a small fifth inferior tooth, their tooth-formula will be : —

p 3 ^ 2 p. 3, p. 2, p. 1 ; m. 1, m. 2

2 3 p. 2, p. 1 ; m. 1, m. 2, m. <i

To sum up. The nvimber of premolars is constant in all the genera of Lagomyidye,

and the same as in Lepus ; whereas that of the true molars varies in the different genera ;

not rice versa, as has been supposed by Lydekker *, Flower f, and Zittel %.

The iipper m. 3, always present in Lepus, is always absent in the Lagomyidte. Of the

lower true molars, m. 3 is always present in Lagopsis and Lagomijs, when not lost in the

fossil : it is always absent in Prolagm ; while in TUanomys this tooth is rarely absent

in one species, T. Fontannesi, more frequently in the other, T. visenoviensis, but presumably

always present in young specimens of both.

1. Genus Titanomys.

TUanomys, H. v. Meyer, Neues Jahrb. 1843, p. 390.

Lagodus, Pomel, Cat. meth. Vert. foss. Loire et Allier, p. 41 (1853) ; Deperet, Arch. I\Iits. Lyon, iv.

p. 12(5 (1887).

Lagomys (subg. Amphilagus), Pomel, op. cit. p, 42.

Lagomys, Lydekker, Cat. Foss. Mamm. Br. Mus. i. p. 255 (1885).

Lagomys (Lagopsis), Schlosser, Pal. Oestr.-Ung. viii. p. 8fi, foot-n. 4 (1890), p.p. ; Deperet ?, Arch. Mus.

Lyon, V. p. 58 (1892).

Titanomys visenoviensis.

Titanomys visenoviensis, H. v. Meyer, Neues Jalirb. 1843, p. 390; Gervais, Zool. et Pal. fr., prem. ed.,

Expl. No. 46, pi. xlvi. fig. 2 (1848-52) ; Bronn, Lcth. Geogn. iii. p. 103 (1853-56) ; Gervais, Zool.

et Pal. fr., deux, ed., p. 50, pi. xlvi. figs. 1, 2 (1859); H. v. Meyer, Palieontogr. xvii. p. 225,

pi. xlii. (1870) ; Filhol, Ann. Sc. Geol. x. p. 26, pi. ii. figs. 25, 26, pi. iii. figs. 1-18 (1879) ;

Schlosser, Palaontogr. xxxi. p. 29, pi. xii. figs. 36, 38, 39, 41, 43, 45, 47, 48 (1884) ; Zittel, Handb.

d. Palajont. i., iv. p. 552 (1891-93).

Titanomys trilohus, Gervais, Zool. et Pal. fr., prem. ed., Expl. No. 46, pi. xlvi. fig. 1 (1848-52).

Lagodus picoides, Pomel, Cat. meth. p. 41 (1853).

Lagomys (subg. Amphilagus) antiquus, Pomel, op. cit. p. 43.

Ampkifagus antiquus, Schlosser, op. cit. p. 30.

Lagomys visenoviensis, Lydekker, Cat. Foss. Mamm. Brit. Mus. i. p. 258 (1885).

Sistorical Sketch.

In announcing his new genus Titanomys (type species T. visenoviensis), from the Lower

Miocene of Weisenau near Mayence, H. v. Meyer characterizes it as having prismatic

cheek-teeth, agreeing in size and number and resembling in form those of Lagomys,

with the difference, however, that the lower molars of the fossil present a distinct

* Cat. Foss. Mamm. Br. Mus. i. p. 255 (1885) ; Nicholson & Lydekker, Manual of Palseont. ii. p. 1412 (1889).

t Flower & Lydekker, ' Introduet. to the Study of Mammalia,' p. 491 (1891).

t Zittel, Handb. d. Pala30nt. i., iv. p. 551 (1891-93); id. Grand;!, d. Paloeont. p. 825 (1895).

FOSSIL AND EECENT LAGOMORPHA. 437

posterior appendage (" Hintoransatz ") not known to exist in Lagonii/s, while the

Weiseuavi Rodent lacks the distinctly developed tooth-particle (-'Zahutheil ") in the last

lower molar of existing Lac/07ni/s and of those of the "ossiferous breccia"; by which

is apparently meant the Prolagus of Corsica and Sardinia.

We meet here at the outset with several incorrect statements. The upper molars are

not, as we shall see later, j)rismatic, and the lower are only incompletely so. By the

allei^ed agreement in number of the molars of both Titanomys and Lagonii/s we are

to understand that both genera have fovir lower cheek-teeth, the author believing at that

time that the existing Lugomys has four mandibular cheek-teeth, while in reality there

are five. H. v. Meyer considered the fifth small cylindric tooth ol Laguiiujs to be a third

prismatic particle connected with the anterior molar, as is the case in JProlagus. The

author further makes a distinction — which is repeated two years later in his ' Fossil

Mammals of Qi^ningen,' where incidentally the genus Tltanomijs is mentioned * — between

a distinct " Hiuteran.satz " in the 2X)sterior molars of Titanoinys, and the " distinctly

developed " posterior or third " Zahutlieil " of the last molar in some Lagomyidoe, without

beina: aware that the tw'o are one and the same thing and homologous.

The characteristics given of the upper molars are not incorrect, but rather vague,

showing that the author did not succeed in making out the pattern of the triturating

surface, as is confirmed also by his manuscript drawings subseqiiently published by

Schlosser.

In the first edition of his ' Zoologie et Paleontologie francaises,' Gervais figures, without

description, two mandibular rami from the Lower Miocene of Saiut-Gerand-le-Puy

(Allier) ; the fig. 1 of pi. 46 is named Titanomys trilobus, the fig. 2 T. cisetioviensis. In

the explanation of the plate it is stated that the identification with T. visenovieims rests

on a comparison with a mandible of this species from Germany in the British Museum

(this is under No. 2149.3, from Weisenau). Gervais had no upper molars from the French

deposit, but says that those from Germany, which are in Loudon, " sont assez semblables

a celles des Lapins, mais beaucoup pkis courtes et plus arquees," adding tiiat they are of

the same form as those from the Miocene of the Limagne, called Marcuinomys by Croizet

and Fl(ityodo)i by Bravard. These are two manuscript names.

In 1853 Pomel issued a small work of a high standard on the fossil vertebrates of tlie

Loire and Allier basins, pretending to be nothing more than a catalogue f . The

descriptions are in consequence very short, and as there are no figures, the utility

of this excellent publication has been rather limited. The Leporidae family opens J

with a new genus, Lagodus, from the Tertiary of Langy ; the only species, L. picoides,

scarcely larger than Lagomys pusillus, is based mainly on the upper and lower cheek-

dentition, the description of which 1 transcribe at length for future reference. From

this it will be seen that the author assigns to his genus Lagodus five upper and four

* 'Zur Fauna d. Yorwelt. — Foss. Saugethiere etc. vou (Jiningen,' p. 10 (1845).

t Catal. method, et descr. des Vert. foss. deoouv. dans le Bassiu hydrogr. sup. de la Loire, et surtout dans la

VaUee de . . . 1' Allier (1S53).

t Op. cit. p. 41.

438 DR. C. I. FORSYTH MAJOR ON

lower cheek-teeth ; the first superior was missing, and from the form of the alveolus it

is declared to have heen very small. " En haut il paralt y avoir eu cinq molaires ; la

seconde est plus etroite que chez les Lagomys et pour ainsi dire reduite a une seule lame

marquee en travers de deux plis d'email, de maniere a figurer presque trois croissants

concentriques ; les trois autres ont deux lames dont la premiere est simple, et la seconde

pourvvie des deux replis d'email de la dent qui precede, excepte a la cinquieme dent,

oil elle est plus petite . ." The lower teeth are said to be four in number, " par

absence de la derniere. Premiere tetragone divisee par deux sillons en deux cylindres

comprimes, dont I'anterieure plus saillante est aussi un pen plus large et la seconde a

en arriere un petit pli d'email partant de Tangle interne surtout evident a la derniere

molaire et s'effa^ant assez tard par la detrition. Ces cylindres sont moiiis comprimes

d'avant en arriere que chez les Lagomys, et leur disque de detrition est ovale oblong,

brusquement attenue en angle du cote externe, arrondi vers rinterne."

From the later descriptions of Titanomys and from examination of originals, we are

enabled to refer Pomel's Lagodus to the former genus, and at the same time to appreciate

the accuracy of his description. But without this help and iu the absence of figures,

it becomes ditRcult to form an exact conception of the comj)licated pattern of the

upper teeth, from their necessarily too short characteristics by Pomel. Hensel, when

describing the teeth of Prolagus (his Myolagus), was on the look-out for allied forms ;

he gives in full Pomel's description of Lagodus *, but fails to see the curious relationship

existing betAveen the upper premolars of the former and all the U2:)per cheek-teeth of

the latter.

The small enamel fold described by Pomel as starting from the internal angle of the

posterior lamina in the three mandibular teeth behind the first is the " Hinteransatz "

of H. V. Meyer's Titanomys. The relations of the latter to his Lagodus are not discussed

by Pomel ; he suggests tlie former to be probably the same as JProlagus sansaniensis

(Lartet's Lagomys sai/sa>riensis).

Pomel's Ai)i2)hilagus rests on lower jaws ; he considers it to be a subgenus of Lagomys,

apparently because in both there are five lower cheek-teeth : " la derniere molaire " (in

AmphUagiis) " ties petite est cylindrique et caduque, en sorte qu'il ne reste souvent que

quatre dents a la machoire." The form of the anterior lower premolar is the same as in

" Lagodus " and Titanomy s, and very diff'erent from the premolar of Lagomys, a

character which at once suggests that "Lagodus" and AmphilagHs may be identical,

and that the absence of the small posterior apj^endage in the lower molars attributed to

Amphilagvs is due to the specimens being from older individuals than those assigned to

" Lagodus."

In Bronn's ' Lethsea Geognostica,' Pomel's Lagodus is given as a synonym of

Titanomys visenoziensis on the authority of H. v. Meyer {'^Jide Meyer in litt.').

The second edition of the Zool. et Pal. fran^. (1859) gives good reasons for considering

Titanomys trilobus as the young of T. risenociensis. Of the last lower molar in particular

Gervais says: — "la derniere monire encore avec assez d'evidence un troisieme lobe, qui

* Zeitschr. d. deutsclj. geol. Ges. viii. p. G&9 (lS5<i).

FOSSIL AXD EECENT LAGOMOEPHA. 439

est d'ailleurs petit et qui, a un Age plus avance, eut etc confoadu avec le second lobe de

lameme dent, commecela se roit chez le sujet de la figure 2" {T. vlsenoviensis) ; and he

goes on stating, as Pomel had done for his Lagodus, that this little posterior column is

gradually worn away. It is mentioned by Gervais only in the last molar, and his iigures

show no trace of it in the anterior molars.

Referring to Pomel's Lagodus and Amphilagus, Gervais launches an ungenerous and

unfounded accusation against this author, alleging that the former genus is " du moins

en partie " based on his, Gervais', figure of Titan, trilobus, and that An/pkilagus rests ou

fig. 2, representing Titan, visenoviensis. jSo mention is made of Pomel's description of

the upper dentition of " Lagodus.'' If the latter writer failed to recognize in his Lagodus

and AmiMlagtis H. v. Meyer's Titanomys visenoviensis, it was perfectly excusable at the

time he wrote, wlien this species had been so very imperfectly diagnosed both by

H. V. Meyer and by Gervais, who both failed to make out the 2)attern of the upper

teeth. Up to this day we have not been ])etter oflp with regard to the upper cheek-teeth

from the type-locality Weisenau.

It would have been fairer on the part of Gervais to acknowledge that Pomel's

descrijition of the inferior molars of " Lagodus " had gone far in enabling him

(Gervais) to recognize the non-validity of his species T. trilobus, and that Pomel had

besides described more accurately than himself tlie lower teeth, in demonstrating the

presence of the " petit pli d'email " in all the posterior teeth of younger specimens. He

certainly could not have based this statement on Gervais' fig. 1 of the young specimen,

where only the last molar shows a posterior appendage. The accusation with regard

to Amphilagus is quite as unfounded as the first one. Pomel assigns five teeth to the

lower jaw' of his genus, Gervais' figure shows only four ; the description of the first tooth

of Amphilagus does not exactly agree Avith the tooth in Gervais' figure, from which last,

moreover, it could not be made out that the two cylinders of each of the posterior teeth

are united by cement, as stated by Pomel to be the case in his Amphilagus. Other

particulars occur in the description of Amphilagus, which miglit at once have convinced

an impartial critic that Pomel based his descrij^tion on originals. These were, many

years later (1879), handed by M. Pomel himself to Prof. Pilhol *.

In his posthumous paper (1870) on the skeleton of a young Titanomys visenoviensis

from the Lignite of Ptott near Bonn, now in the British Museum (No. 41085), H. v.

Meyer mentions rooted cheek-teeth in Titanomys, and he has been understood to

state that only the deciduous teeth of this genus are provided with roots. However,

when reading attentively H. v. Meyer's paper — I might almost say, in reading between

the lines as well — one necessarily comes to the conclusion that in adult specimens

the permanent molars were also rooted, and that the author himself had suspected this

fact, but hesitated to jiroclaim it. Two kinds of rooted Titanomys-teeth are mentioned in

the paper. With regard to those of the Ilott skeleton, the author states that their

triturating surfaces are concealed in the matrix, so that their opposite ends only could be

examined ; but this does not hide the fact, he continues, that the two posterior upper

* Aim. Sc. GJol. X. pp. 27, 28 {ISJ'J).

4i0 DE. C. I. FOESTTH MAJOE ON

teeth were formed as in Lagomys. This evidently implies that they have no roots ; for

the writer proceeds to state that in the teeth anterior to those just mentioned lengthened

roots can be seen. In the two anterior cheek-teeth of the lower jaw, H. v. Meyer

describes a short crown and a long root, composed of two strongly converging parts;

and these two teeth seem to be situated somewhat higher than the two posterior, which

suggests that they had not yet emerged above the alveolar margin. Contrary to the

anterior rooted teeth, these two posterior ones are described as " prismatic " ; the whole

of their crown has an enamel coating, and is not completely closed below. The author

concludes that the teetli seem to indicate that the animal was of immature age, a

supposition which would explain the differences of the anterior teeth from those of

Jjagomi/s.

As a matter of course, in the lagomorphoiis Rodentia with permanent cheek-teeth

growing by persistent pulj)s, the deciduous teeth are rooted too as in the Rott skeleton.

But the author proceeds to state (p. 128) that he has examined detached teeth of the

Titanomijs from Weisenau of two kinds : on the one hand, small teeth corresponding to

the anterior teeth of the Rott specimen ; on the other, lower teeth ditfering from the

last by a lengthened prismatic crown and quite insignificant roots ; and upjDer teeth

as well, of larger size than those corresponding to the U2:)per anterior teeth from Rott,

supposed by H. v. Meyer to be possibly deciduous. In the larger teetli the roots are

said to disappear almost comjdetely ; " die flach prismatisohe, gekrummte Krone vertritt

zugleich die Hauptwurzel, und es wird nur aussen oben ein kleines "Wiirzelchen wahrge-

nommen, das audi in einer entsprechenden Stelle des Kiefers eingrcift, wahrend das an

der Innenseite mit einer Rinne versehene Zahnprisma die eigentliche Alveole ausfiillt."

Prom what will be seen later on, these larger teeth, upper and lower, are in fact the

permanent teeth of Titanomys, as H. v. Meyer hesitatingly suggests. Therefore there is

no foundation in the distinction — such as is drawn by Deperet — of two genera, founded

on the presence or absence of roots in the permanent teeth, viz. : —

(1) Titanomys, with roots in the deciduous set only.

(2) Lagodus, with roots in the permanent teeth as well (premolars and true molars).

Proceeding with our historical sketch in chronological order, we next have to

consider Filhors descrij)tion of Titanomys cisenoviensis from Saint-Gerand-le-Puy

(AUier) *, which has already been quoted more than once in the preceding pages.

Among the synonyms of this species are given Ariiphilagus antiquus, Pom., and

Lagodus pico/des, Pom. : the identification of the former rests on one of the type

specimens of Pomel ; the latter is not discussed in the paper. An important character

noted by Filhol is the relatively considerable longitudinal extension of the bony

palate in Titanomys. The shortness of the bony palate in lagomorphous Rodents is

doubtless a specialization ; but by its greater extension Titanomys approaches more

the condition of other Ptodentia and Mammalia generally. The same is true of

Falcpolagus, from the Miocene of North America, which presents curious resemblances

with Titanomys in its dentition also. Moreover, we meet with a lengthened bony

* Ann. Sc. Geol. x. p. 26 (1879).

FOSSIL AND EECENT LAGOMORPHA. 441

palnte in Lepus valdariiensis, Weith. *, from the Upper Pliocene of Tuscany, and

in three existing Leporines, Lepus hispidus. Pears., from the foot of the Himalayas,

L. Netscho'i, Schleg. & .lent., from Sumatra f, and Romerolagus Nelsonl, Merr., from the

Popocatepetl (Mexico) %, all three of which have other generalized characters in common

with each other and partly with Palceolagns.

Description of Original Specimens.

1. Tiie Rott Skeleton. —In. its present condition, of the two anterior lower cheek-teeth

described and figured by H. v. Meyer, only tlie imprint is i^i'eserved, with the exception

of the anterior half of the front tooth, which is still in place. Prom what can still be

seen, and with the help of H. v. Meyers description and figures, there remains not the

slightest doubt that these two anterior teeth belong to the deciduous set, since they

bear the characters oi milk-teeth, viz., a short crown and (two) long roots, much

diverging from each other dowuAvai'd. The number of teeth in front of the tw^o

posterior in the npjier jaw is left uiuiertain in the figures and text of the original

memoir. A close examination shows tliat there are three of them : the first apparently

is provided with a stouter internal and a somewhat weaker external root ; the two

following with one internal and two smaller external roots, the latter strongly diverging

from the shaft in opposite directions. Here, too, Ave have the characteristic features of

milk-teeth, of which there are consequently three upper in Titanomgs, as might have

been anticij)ated by analogy to Fj-olagiis. The immature condition of the specimen

can be fiu'tner inferred from the fact that the two posterior teeth, viz., the fourth

and fifth in ihe series, are not yet on the same level with the three iu front of them.

As these two posterior teeth are broken at their lower ends, nothing can be stated as to

their roots.

Still less — and this applies to all the teeth of the Pi,ott specimen — can be made out

about the pattern of their tritur.itiug surface, which, as noticed already by H. v. Meyer,

is concealed iu the matrix. This deficiency is partly supplied by some teeth from the

type-locality of Weisenau, in the British Museum.

2. Titanotnys risenoviensisfroin Weisenau. — A fragment of the right upper jtiw from the

Lower Miocene of Weisenau, iu the Geological Department of the British Museum (21495),

PI. 36, fig. 19, shows the two posterior piemolars, p.l, p. 2, and part of the alveolus of

the anterior jiremolar, p. 3. These upper teeth were seen by Gervais, who alludes to

them §, contenting himself with the above-reported general remarks. The first of the two

premolars preserved, p. 2, at once calls to mind by its general form the anterior upper

premolar, p. 3, of Lepus, and to it therefore may be justly applied Gervais' remark

referring to all the ujjper teeth in London, viz., that they are " assez semblables a celles

des Lapins." The general outline of this tooth is somewhat triangular, the broader basis

heing on the inner side, which is imperfectly divided by a slight notch into two abraded

* Jabrb. k.-k. geol. Eeichsanst. vol. xxxix. p. SO (1889).

t ' Notes from the Leyden Museum,' vol. ii. note sii. p. 5'> (18S0).

J Proc. Biol. Soc. Washington, s. pp. 160-174 (1896).

§ Zool. et Pal. Fran,:;. 1st ed. t. ii. expl. no. 46 (1848-52) : 2nd ed. p. 50 (1859).

SECOND SERIES. — ZOOLOGY, VOL. VII. C2

442 DR. C. I. POESYTH MAJOR ON

cusps (8 & 9). Proceeding outward, we meet with two enamel folds starting from the

anterior side of the tooth. The one placed more internally (b) is hy far the larger of the

two ; it opens freely on the anterior side, and thence proceeds first internally, and then,

gradually attenuating, postero-externally, thus assuming approximately the form of

a crescent, whose anterior horn is much shorter than the posterior. Both horns are

delimited externally hy a cusp (6), having its long axis almost parallel to the long axis of

the skull, and protruding Avith its internal convex horder into the enamel fold just described,

while its shorter and almost longitudinal external border forms the inner margin of the

much smaller second enamel fold (c). On the outer side of the tooth we meet with a large

bulging enamel tubercle (5), worn by attrition on its inner side only, and showing thus that

the outer side in this otherwise much-worn tooth is only partially affected by trituration.

The second tooth, p. 1, presents the general contour of the crown of lagomorphous

Rodents, the transverse diameter largely predominating over the longitudinal : the

anterior border is slightly more convex than the posterior. The minute pattern of the

triturating surface, however, is very different from that which we are accustomed to

consider characteristic of upper leporine molars. The main difference from p. 2 consists

in the two enamel folds being .shut out from the anterior border by a transverse anterior

lobe, Avhich in p. 2 is apparent only in a much reduced condition, its outer portion being

entirely wanting. In p. 1 the anterior lobe or " wall " delimits the anterior horn of

the enamel fold (b) on its front side, so that in this tooth the anterior horn is much more

lengtheued transversely than the posterior. As compared with p. 2, p. 1 has undergone,

as it were, a lateral pressure, by which the various parts of the surface have been forced

into a more transverse direction. This is apparent, especially in the strong cusp (6)

separating enamel folds Ij and c, which is no more longitudinally directed as in p. 2

but has likewise assumed the form of a crescent with its convexity projecting

inward into enamel fold b, and forming externally the inner margin of enamel fold c.

The latter has in its turn assumed a more transverse direction, and is only incompletely

shut out from the outer border of the tooth by a blunt enamel tubercle (5), occupying

mainly the postero-external part of the tooth. The summit only of this tubercle is

slightly worn.

The inner border of p. 1 is more distinctly divided than in p. 2 into two abraded

cusps l)y a vertical groove, manifesting itself on the triturating surface in the shape of

a short enamel fold, or notch (a).

The levelling effect of trituration — favoured by the enamel folds in both teeth being

more or less completely filled with cement, — together with the more transverse direction

assumed by the folds and cusj)s of p. 1, tends to produce a lophodout character of its

triturating surface ; or rather, we haA'e a selenodont type leaning towards lophodonty.

3. Titauomys visenoviensis, from the Allier (France). Br. Mus. 31094 (Bravard Col-

lection).— A detached tooth (PI. 36, tig. 12) is more Avorn still than that just described,

as revealed by its triturating surface being more flattened and the enamel folds more

narrowed. It can only be either p. 1 or m. 1. P. 3 is quite out of the question, as, to

judge from its alveolus, it was a very small tooth ; p. 2 is reduced in its antero-external,

FOSSIL AND EECENT LAGOMOEPHA. 443

ni. 2 in its j)Ostero-exterual portion (compare fig. 19, PI. 36, with fig. 6) ; so that the choice

remains only hetweeu p. 1 and m. 1. It resembh's closely the p. 1 described ; only it is

narrower, and the anterior lobe of the latter is more developed in its internal portion,

althongh the inverse w"as to be expected, tlie p. 1 described being less worn. For tliese

reasons I think it more likely to be m. 1. This tooth shows tw'o small roots on the outer

side ; on the inner side the crown gradually thins out downward into a single large root.

It cannot be a milk-tooth, because the two small external roots do not diverge downwards,

but run parallel with each other. We have here another proof, if one were needed, that

in Titanomys visenomeiisis the upper teeth are provided with roots ; although this fact

has been denied with regard to this species of the Lower Miocene.

Mandibular teeth of Titanomys visenoviensis. — As a characteristic feature of the lower

cheek-teeth of T. visenovietisis, II. v. Meyer makes mention of a small posterior lobe,

calling it a distinct posterior appendage (" ein dcutlicher Hinteransatz ") *. About the

occurrence of this small particle much uncertainty prevails. When establishing the

genus, in the paper just quoted, H. v. Meyer mentioned it in a general way as present in

the lower cheek-teeth, seemingly implying that all of tliem were provided with this

appendage. In his posthumous memoir, however, speaking again of the Weisenau speci-

mens, he says that it occurs on Win posterior cheek-teeth and would have disappeai'ed by

effect of attrition t- Pomel assigns it to the three posterior cheek-teeth of " Lagodus

jyicoides," adding that it takes its origin from the internal angle, that it is more evident

especially in the last molar and disajjpears rather late by attrition |.

According to Gevvais § it would occttr only on the fourth tooth (m. 2), and as a character

of young specimens ; the same is stated by Filhol || , who had at his disjjosal a considerable

number of lower jaws. Schlosser ^ styles it a third lobe occttrring as an anomaly

(" abnorm vorkommend ") in "m. 3" (meaning m. 2) of Titanomys visenoviensis;

although in the same memoir he figures manuscript drawings by H. v. Meyer, wdiere

it is shown in two molars. This same small lobe occurs in Palceolaff/is also; it is

transitional in one species, P. Haydeni, as described l)y Cope **, apparently persisting

in another sjiecies, P. triplex ff. On a former occasion I incidentally pointed out the

interest attached to it from both a phylo- and ontogenetic point of view J J.

As to the occurrence of this small lobe or cusp in T. visenoviensis, my own observations

tend to show that it is constantly present in young specimens, not only of the posterior,

but also of the anterior lower teeth, including p. 2. In a fragment of a right

mandibular ramus of T. visenoviensis from the Allier (Bravard Collection, Br. Mus.

31094-104), PI. 37, fig. 25, exhibiting the two anterior cheek-teeth, p. 1 and p. 2, in a

moderate stage of wear, traces of this iol)e are visible in both these premolars, very

distinctly in the posterior (p. 1).

* Neues Jabrb. 1S43, p. 390. t Talicontogr. xvii. p. 226 (1870).

+ Cat. nn'-th. p. 41 (1853). § Zool. ct Pal. Franc;, sec. ed. p. 50 (1859).

i; Ann. Sc. C4l:o1. x. p. 27 (1879). If Pala-ontograph. xxxi. p. 32 (1884).

** ' The Yerteljrata of the Tertiary Formations of the West," p. 876 (1883).

+t Op. cii. p. 881. Ji Proc. Zool. 8oc. London, p. 203 (1893).

62*

444 DE. C. 1. FOESYTH MAJOR ON

It has been found convenient to give the detailed descriptions of the lower molars of

this and all the other genera in a separate chapter (p. 473).

TiTANOMYS FONTANNESI.

Lagodus Fontannesi, Deperet, Arch. Mus. Lyon, iv. p. 127, pi. xiii. figs. 19-19 c (1887).

Lagomys [Lagopsis) verus, ScLlosser, Pal. Oestr.-Ung. viii. p. 86 (1890) ; Deperet (?), Arch. Mus. Lyon,

V. p. 57 (1892).

Under the name of Lagodus Fontannesi, Deperet described a fragment of an ixpper

jaw, from the Middle Miocene of La Grive-Saint-Alban (Isere), as related to Titanomys

visenomcns-is, H. v. Meyer ; but, in addition to its larger size, he distinguished it by other

more important characters.

Schlosser has sup2)osed, without assigning reasons, that Lagodus Fontannesi, Dep., is

synonymous with Lagomi/s {Lago2)sis) verus, Hens. {^Lagomys oeningensis, H. v. Mey.),

and Deperet, in his second publication on the Fauna of La Grive, is disposed to accept

Schlosser's views. It may be asked at once, Avhat then becomes of the left palate,

figured and desci-ibcd by Deperet in his first memoir *, where he considers it, rightly in

my opinion, to belong to the Lagomys rerus. As this question will be discussed under

the head of Lagopsis verus, when it will be shown that Deperet's original view in

distinguishing between " Lagodus Fontannesi " and Lagomys verus is the correct one,

we have for the present only to deal with Deperet's first memoir, in which " Lagodus

Fontannesi" is described, and where he asserts that it is distinct as a genus from

Titanomys viseno^iensis of the Lower Miocene.

For this Deperet gives two reasons. In the first line he maintains that his Lagodus

preserves in its adult dentition part of the characters of the deciduous dentition of

Titanomys visenoviensis, meaning that in the latter the milk-teeth alone are rooted,

while in the former the permanent cheek-teeth arc rooted as well. I have already

disposed of this supposed difference, by showing that the permanent teeth of Titanomys

nisenovicnsis are likewise rooted.

Deperet's second reason is given in the following words : — " Le Lagodus Fontannesi

se distingue d'ailleurs facilement du Titanomys visenoviensis . . . par quelques differences

dans les dessins d'email qui ornent la surface de la couronne " (i. e. of the upper molars).

" D'apres M. Filhol, le lobe posterieur des molaires superieures du Titanomys d'Auvergne

est orne d'un double pli en chevron entourant une pointe externe ; dans le Lagodus de

La Grive il y a trois plis en chevron concentriques et pas de pointe exterieure bien

manifeste"t.

The enlarged figures of the triturating surface in the teeth of "Lagodus Fontannesi"

and Titanomys riseiioviensis do not help us, as they are sadly inaccurate. The artist who

drew the former J completely failed to understand the pattern ; while in Filhol's enlarged

drawings § the artist has not even made an attempt at accuracy, contenting himself

with drawing the outlines of the teeth, and leaving out almost completely the details of the

* Arch. ilus. Lyon, iv. p. 104, jil. xiii. tig. 17 (1SS7).

t Op. cit. p. 128. i Op), dt. pi. xiii. fig. 19 b. [§ Op. cit. pi. iii. fig. 15.

FOSSIL AND EECENT LAGOMOEPHA. 445

crown's surface. In the figures which I give of the teeth of both forms *, no essential

difference is to be seen in tlie pattern. The disagreement in the description of the two

writers finds its explanation in the somewhat loose way of describing the triturating

surface, i. e. hj the failure to distinguish between a dentine surface bordered by two enamel

ridges which alternates with an enamel fold filled with cement, so that only the two

enamel borders of the fold appear on tlie surface. As an outcome of this alternation we

find, when proceeding from the inner side of the tooth to its outer side, the following

succession in the middle line of the tooth : enamel ridge ; dentine ; enamel ridge ; cement ;

enamel ridge ; dentine ; enamel ridge ; cement ; enamel tubercle of the outer side.

Apparently the two writers do not always apply the term " chevron " to the same

thing. Filhol, speaking of the " deuxieme element " of the tooth, by whieli he means

the part of the crown backward from the anterior lobe, his " premier element," says :

" Chez les Titanomys, on peut le considerer comme constitue par un chevron a sommet

interne, dont les deux extremites circonscrivent une pointe externe. Ce premier chevron

est borne en dedans par un deuxieme chevron dont le sommet correspond au bord interne

de la dent. Ce mode de structure est surtout bien marque sur la troisieme molaire"!.

This description, which is quite correct as far as it goes, applies equally well to the

species of the Lower and to that of the Middle Miocene, as may be seen by a com-

parison of the figures (Pis. 36, 37, 39) ; by consulting the figures it may be further seen

that what the author calls chevrons are the spaces of dentine bordered by enamel ridges,

which spaces mark the position of enamel cusps before wear set iu.

Deperet, in describing the same " troisieme molaire," I. e. the posterior of the three

premolars, of Laxjodiis Fontcmnesi, says :■ — " Cette couroune se compose de deux prismes

d'email etroitement accoles, un pen niieux distincts en dehors que du cote interne, qui est

de forme arrondie. Le prisme anterieur [Pilhol's premier element] est compose d'un

seul pli d'email transverse ; le prisme posterieur au contraire, a surface triturante coupee

obliquement en arriere, presente deux plis d'email en chevron a pointe interne, ce qui

dessine sur la couronne trois petits croissants concentriques, si Ton compte la lamelle

d'email qui limite le bord interne de la couronne "$.

It is certainly not accurate to describe the single cylinder of which these upper teeth

consist as composed of two enamel prisms " etroitement accoles." Apart from this,

Deperet's descrij)tion, like Filhol's, applies to both Lagodus Fontcmnesi and Titanomys

visenomensis. By " deux plis d'email en chevron a pointe interne," the author evidently

has in view, firstly, the larger, internal, of the two enamel folds ; secondly, the crescent-

shaped cusp (6) external to it, which by the effect of wear presents a dentinal surface

bordered l)y an outer and an inner enamel ridge. By counting, moreover, the enamel

border of the internal side of the crown, Deperet arrives at the number of three " petits

croissants concentriques," which on the following page are called " trois plis en chevron

concentriques." Lilhol leaves oiit of account the enamel fold by which his two chevrons

are separated.

* PI. 36. figs. IS, 19; PI. 37. fig. Tl; PL 39. fig. 16 (Tkanoiinjs vhemvlensis). PL 36. figs. 6-8. 12-1.5

.{T. Fontannesi). t Op. cit. p. 30. t Op. cil. p. 127.

446 DE. C. I. FOESTTH MAJOE OX

As a result of this minute analysis we find that there exists no essential difference iii

the tooth-pattern of the two supposed genera.

The roots of the Titanowi/s-Taolars have next to he described. I have elsewhere dealt

incidentally with the conditions in Titanomys {Lagodus)* . I was impressed by the

fact that the chief points of wear are on the inner side in the upper, on the outer in the

lower molars, and that these parts are the first to appear lengthened (vertically) in

teeth in a condition intermediate between brachyodonty and hypselodonty, while the

outer sides of upper, and the inner sides of lower molars remain, as it were, in a passive

condition (for upj)er molars of Titanomys see PI. 39. figs. 1, 2, 5, 13, 14, 19). It then

appeared to me that the upper teeth of Titanomys showed the hypselodonty — which,

as above demonstrated, is here in fact " accompanied by a gradual and essential change

of the pattern of the crown "f — to extend gradually towards the outer side. In the

description of the pattern of the ProZ«Y/?is-molars (pp. 452, 453) I have reconsidered my

former ^dew, and have been able to show that the obliteration of the original pattern is

chieflv the consequence of an atrophy on the outer side ; whereas the secondary pattern

is brought about by a new addition, starting from the inner side and directed chiefly

inward. It remains none the less true " that the vertical elevation of the crown, the

first stage towards hypsodonty, always has its starting-point from the inner side of

upper molars "+. I added at the same time that "the inner root (of the upper molars)

which ultimately will remain open, gradually extends outward, increasing in size, and

receives a coating of enamel "§. It is agaiiist this latter assertion especially that the

Hev. Pcre Heude has directed a criticisni, couched in energetic terms Ij. When he

begins by saying that I had not demonstrated my assertion, he is perfectly riglit; but I

had at the time no other intention than to assert, reserving full demonstration for a

work on the Lagomorpha under preparation, as intimated on p. 208.

The Rev. Pere's arguments are to the effect that the roots of teeth cannot be imagined

to receive a coating of enamel, because brachyodonty " est un arret de dcveloppement,

une fixation par cessation de mouvement, une deterioration du fut transforme en racine.

Consequemment la dent ne jieut revenir a son mouvement initial." In order to

demonstrate that " logiquement " hypselodonty is more primitive (" plus ancien ") than

brachvodouty, and that " rcellement ces deux faits sont phylogeniquement independants,"

the Rev. Pere adduces the incisors of Rodentia. " D'aatre part toutes les incisives des

Rono-eurs etaut essentiellement hypsodontes et a toutes les epoques, au point qu'elles

emportent la definition de I'ordre, il faut admettre qu'elles n'ont pas varie, qu'elles ont

un caractere commun fixe, et qu'a ce litre I'hypsodontisme est plus general que le

brachyodontisme."

It is not hypselodonty, as such, which is the more jirimitive condition, but tlie

o-rowini;- of a tooth by a persistent pulp. And, since hypselodont teeth continue to

o-row by persistent pulps during the greater part or the whole of the animal's life,

* Proc. Zool. Soc. London, 1S93, p. 206. t //). t Il>. § L. c.

II ' Memoires coiicernant I'Hist. natiirelle de TEmiare Chinois, jiar dcs Pures de la Compagnie de Jesus,' t. ir.

p. 75 (1808).

FOSSIL AND EECEXT LAGOMOKPHA. 447

they may, in a sense, be termed primitive ; but, as a matter of coui'se, bracbyodont

and semibypselodont teeth, before they are perfectly developed, have the cavities at

their bases open as well as bypselodont teeth ; and when they are in this condition,

their brachyodonty is not yet " nn arret de developpement." Ontog-enetically and

" logiqiiement," every bypselodont tooth passes through a bracbyodont condition, the

shaft only gradually increasing in length. Phylogeuetically, brachyodonty is also more

primitive than hypselodonty, as is known to all scientific morphologists wlio have a

knowledge of paleontology.

On PI. 39. tigs. 19 and 20, I liave delineated side by side in the anterior view a

posterior upper right premolar, p^, of Titauomys Fontaunesl — the same specimen

of wliich the upper view is figured on PI. 36. fig. 8 — and an upper right molar of

a young Pteromys, in which the roots are not yet closed. Fig. li< represents the

anterior view of a right upper molar of Tit. viseaovieusis, figured i]i upper view on

PI. 36. fig. 18. Now, if we are entitled to call roots, even though they be

imperfectly developed, the three prolongations of the crown in Pteromys (fig. 20),

I think we are justified in applying the same term to the evidently homologous

parts in the figured teeth of Tltanomys (cf. figs. 14 and 19, and figs. 1, 1, 5, and 13),

and in repeating what I have said formerly *, that the inner root of Tltanomys, which

ultimately will remain open, increases in size and receives a coating of enamel.

Even perfectly adult bracbyodont teeth preserve at their extremity a minute

opening for the passage of nerves and vessels, so that it may be left to individual

judgment at which phase in the ontogeny or pbylogeny of a tooth we may begin

to use the term " root." Having no desire to juggle with words I would, be

quite ready to desist using this term for the part of the tooth of Tltanomys which

is the hoinologue of the inner root of Pteromys; but thereby nothing would be

altered. The question at issue is, whether or not a coating of enamel lias extended

to that part; and that this has been the case is shown [)lainly enough by the figtu'es.

It is interesting to compare the tooth of Tit. vlsenooleiisis (fig. 14) with those of

Tit. Fontannesl (figs. 1, 13, 19). The small outer roots are perfectly closed in the

former and more detached from the shaft than in the latter. The tooth of the

former, as shown by the upper view (PI. 36. fig. 18), is from an old individual; but in

none of the numerous upper premolars or molars of Tit. Fontannesl have I met with

closed outer roots. The coating of the enamel does not extend so far downward on

the inner side in Tit. vlsenovlensls as in Tit. Fontannesl.

A further diff'erence between the Lower and the Middle Miocene species is also

characteristic. In the former (PI. 39. fig. 14) the external part of the crown extends

more outward than in Tit. Fontannesl, beyond the small roots ; this character has

been already noticed and explained in the description of the triturating surface, as

due to the atrophy of the outer region being less advanced in Tit. olsenoclensls than

in the more recent species.

To proceed now to a closer examination of the small outer roots of the upper molars

and premolars of Tltanomys. In a passage, quoted above, p. 4.10, from H. v.

* Proc. Zool. Soc. London, 1S93, p. 206.

448 DK. C. I. FORSYTH MAJOR OX

Meyer's posthumous descriptiou of the E,ott skeletou, mention is made of upper molars

of Titanomys found isolated, but only one small outer root is ascribed to them.

I likewise find that the anterior milk-tooth, d- •^, of the E-ott skeleton has one

small outer root. Almost all the isolated teeth at my disposal, of both species,

exhibit two symmetrical outer rootlets, which represent the lower free terminations

of two prominent ridges on the upper outer region of the tooth, as in the figured

deciduous tooth of Lepus PI. 39. fig. 9, b), with the difference that in the latter the

posterior part of the first appears higher, and the ridges, therefore, more lengthened

than in Titanomys. The ridges, of which the outer rootlets are the lower termina-

tions, are present also in molars and premolars of all Lagomorpha growing from

persistent pulps. Pigs. 7 and 8 (PL 39), representing germs of the first upper true

molar of a rabbit, show them in side view (at the right side of the figures).

In a left ujjper jaw of Titanomys Fovtaunesi the roots of the cheek-teeth are

described in the following manner by Deperet : — "La disposition des racines est

aussi tr^s particulifere, et differe de ce que Ton voit chez les Leporides pour se

rapprocher d'autres groupes de Rongeurs tels que les Spermophiles. Chacune des

quatre dernieres molaires porte trois racines, dont une interne grosse, ovalaire trans-

versalement, et deux externes relativement tres petites et arrondies. L'alveole de

la premiere molaire est petit et rond : il annonce une molaire uniradiculee et a

couronne assez petite " *. The figure of tlie sjiecimen f shows the empty alveoli of

p. 2 and m. 1, so that the mode of disposition of the roots in the jaw can be seen.

Deperet's description is confirmed and supplemented by the figure which I give

(PL 36. fig. 23) of a left maxillary from which the teeth have dropped out.

P. 2 of Tit. visenoviensis, the anterior lobe of which we have seen to be somewhat

reduced antero-externally (PL 36. fig. 19), as compared with the posterior teeth, has

only one outer rootlet (PL 39. fig. 5«) ; in the place of the antero-cxternal rootlet

it displays a citrious conformation, which gives at once a clue to that of the rootless

molars of the other lagomorphous genera, and explains why the upper teeth described

by H. V. Meyer have one outer rootlet only. There is no free antero-external radicle

to this tooth ; bvit, as seen in the side-view (fig. 5 a, PL 39), a raised ridge runs along

its antero-external side down to the bottom, where, as shown in the lower view of

the tooth (fig. 5, t)), it is confluent with the lower opening of the large inner root,

the homologue of the widely open cavity in the genera {Lagopsis, Prolagus, Lagomys,

Lepvs) with rootless teeth.

To judge from its alveohts, p^ of Titanomys Fontannesi was more like p. 1 and tlie

true molars, than p^ of Tit. visenoviensis.

Pig. 2, PL 39. represents [a) the anterior, and {!)) the outer view, of the last upper

molar, riirht side, of Tit. Fontannesi, the iijiper view of which has been figured in

PL 36. fia'. 6. Both outer rootlets are broken off, but they seem to have had a free

* Cliarlts Dqioret, "Eoch. nii- ]:i S^iiccession des Faiiucs de Vnt. llioci'Ees, etc.," Arc-b. Mus. Hist. Nat. Lyon,

t. iv. 1). 171 (1887).

t Oj-i. (it. pi. xiii. fig. 10.

FOSSIL AND EECEXT LAGOMORPHA. 4i9

termination like the teeth anterior to them (figs. 1, 13, 19). The outer view {b) shows the

whole of the outer side devoid of enamel.

The levelling effect of trituration tends to produce a more lophodont character of

the crown. In an unworn condition, however, these teeth present a much more

bunodont appearance, and it requires a very small effort of imagination to trace them

hack — conspicuously so the intermediate in the series, which are more typical — to a more

hrachyodont as well as bunodont form, in which the predominant feature is that the

cusps, while the intervening enamel folds would appear as shallow valleys, are not yet

filled with cement. We meet with such hrachyodont types in the Eocene (classed as

Creodonts and Lemuroids) ; more than any other, the Eocene " Felycodus helveticus

E-iit.," and Plesiadapis, both so-called Lemuroids, show teeth in close agreement with

Titanomys. Let, vice versa, a hrachyodont molar of the shape of " Pelycodus,

helveticus " (PI. 36. fig. 3) or Plesiadcqris (PI. 36. fig. 2) l^ecome somewhat more

hypselodont by the heightening of its shaft, and let the valleys between the cusps be

filled with cement, and the result will he a Tifaiiomys-tooth. This I had in view when,

on a former occasion *, I stated that the structure of the lagomorphine molar can

be traced back to a " pelycodoid type."

2. Geniis Prolagus.

Lagomys, G. Cuvier, Oss. foss. iv. pp. 21, 22 (1812), sec. ed. iv. pp. 200, 203 (1823) ; Rud. Warier,

Kastner's Arch. f. d. gcs. Naturlehre, xv. pp. 1-i, 18 (1828) ; id. Oken's Isis, p. 1136 (1829) ; p. p.

H. V. Meyer, Neues Jalirb. 1836, p. 58 ; p. p. id. Foss. Saugetli. etc. von (Eningen, p. 6 (18i5) ;

Waterliouse, Nat. Hist. Mammalia, ii. p. 32 (1848) ; Lartet, Not. Colline de Sansan, p. 21 (1851) ;

p. p. Fraas, Wiirtt. naturw. Jaliresl). xxvi. p. 171 (1870); Lydekker, Cat. Foss. Mamm. Brit. Mus.

i. pp. 256, 257 (1885), v. p. 325 (1887).

Anoema, Konig, Icones Foss. Sectiles, pi. x. fig. 126 (1825).

Prolagtis, Pomel, Cat. mctli. p. 43 (1853).

Mtjolayus, Hcnsel, Zeitschr. deutsch. geol. Ges. viii. p. 695 (1856).

Arch(eomys, Fraas, Wiirtt. naturw. Jaliresli. xviii. p. 130 (1862).

G. Cuvier was first to recognize that some fossil remains, which belong to the above

genus, are those of a lagomorphine Piodent ; he figured and descrilied them from an

ossiferous breccia of Corsica, and later from a breccia of Sardinia, considering them

to be a species oi Lagomys.

In 1825 Konig figured, in his ' Icones Foss. Sectiles,' a skeleton from CEningen.

H. V. Meyer (1836) notes among the Mammals of CEningen the genus Lagovii/s; the

same, according to Murchison, had been previously suggesied by Laurillard t- H. v.

Meyer further supposes that Konig's Anoema might belong as well to the former genus.

From the Miocene of Sansan (Gers) and Venerque (Haute-Garonne), Lartet mentions

a lagomorphine Eodent of the size of a large rat, which he proposes to unite with

* P. Z. 8. 1893, p. 208.

t R. I. Murchison, " On a Fossil Fox found at (Eningen, near Constance,"" Trans Ueol. Soe. London, iii. 2,

p. 285 (1832).

SECOND SERIES. — ZOOLOGY, VOL. VII. 63

450 DR. C. I. FOESTTH MAJOR ON

Lagonii/s, on account of its having one superioi' molar less than the genus Lepus; adding,

however, that the Sansan fossil has one inferior molar less than the existing Lagomi/s.

For this same Rodent from Sansan, Pomel proposed to create the sub-genus Prolagiis,

on the ground of its differing from Lagomys " par la derniere molaire inferieure, qui a

trois pi"ismes par reunion de la cinquieme molaire a la quatrieme. Du reste, la premiere

est aussi triangulaire. On pourrait nommer I'espece Prolagus sansaniensis." The

hypothetical fusion of two molars, stated here as an undoubted fact, does not stand

close investigation, any more than in the case of Tiiaiiomi/s. But to this I shall return

in the sequel.

An excellent description of the remains of the lagomorphine Rodent from the

ossiferous breccia of Sardinia is eiven bv Hensel. He foimds on them his new trenus

Ilyolugus, and poiats out that one of the two Lagomyidae from ffiningen, Lagomys

Meyeri, v. Tschudi, is closely related to the Sardinian fossil, and therefore likewise to

be placed in the genus Mi/olagm. (It is a pity that the perfectly well-characterized

Mi/olagus has, for priority's sake, to give way to Pomel's " Prolagus," just as it is to be

regretted that Pomel's amply-described Lagodus has to stand back before H. v. Meyer's

imperfectly characterized Tltanomj/s.) Hensel refers to Pomel's Prolagus *, and rightly

observes that the characters mentioned by the latter writer recall to mind the genus

Myolagus ; he considers them, however, to be insufficient for a decision. This was quite

true at the lime when Hensel wrote. It is incorrect to say, as has been done by

H. V. Meyer f, that Hensel based his genus uniquely on the form and number of the

lower cheek-teeth and the position of a foramen mentale. Hensel had laid great stress

also on the pattern of the upper teeth %, a character which H. v. Meyer, as in the case

of Titanomys, studiously avoids discussing.

A step backward is made by Fraas, when he figures and describes a well-preserved

mandibular i-amus from Steinheim under the name of Arclueornys steinheimensis. He

was set right by H. v. Meyer §, who referred the supposed Archceonnjs from Steinheim

to '■'■Lagomys {Myolagus) Meyeri, Tschudi," and in 1870 he atoned for his mistake by

giving a full description of the Steinheim Eodent in question.

Prolagus ceningensis.

Anoeiiia wiiinyciisis, Kuuig, Icoues Poss. Sect. pi. x. fig. 126 (1825).

Lai/omys ceninycnsis, p. p. H. v. Meyer, Neu. .Jalirb. p. 58 (1836).

Lagom;/s wninyensis, Waterliouse, Nat. Hist. Mamnialia, ii. p. 32 (18-18).

Lagomys Meyeri, v. Tschudi, iu H. v. Meyer, Zur Fauna d. Vorwelt. Foss. Saugeth. etc. von ffiningeii,

p. 6, pi. ii. figs. 2, 3, pi. iii. fig. 2 (1815) ; Lydekker, Cat. Foss. Mamin. Brit. Mus. i. p. 257

(1885).

Layovujs xa/)saniensh\ Lartet, Not. Coll. de Sansan, p. 21 (1851).

Frolayiis nunsainensis, Pomcl, Cat. metli. p. 43 (1853).

* Oil. cit. p. 702. 1 I'alaiioutogT. xvii. p. 228 (IS70).

+ Oj,. cit. p. sy.5. § Neu. J;ihrb. 1864, p. lt»7 ; 18(35, p. S43.

FOSSIL AND EECENT LAGOMOEPHA. 451

Myolayus Meyeri, Hensel, Zeitschr. deutsch. geol. Ges. viii. p. 699 (185G) : Fraas, Wiirtt. naturw. Jalircsh.

xxvi. p. 171, pi. V. figs. 2-16 (1870) ; Schlosser, Palseontogr. xxxi. p. 28, pi. xii. fig. 44 {1884).

Archceomys steinheimensis , Fraas, Wiirtt. Naturw. Jahresh. xviii. p. 130, pi. ii. fig. 19 (1862).

Lagowys ( Miiiilnf/ns) Meyeri, H. v. Meyer, Neu. Jalirb. p. 197 (1804), p. 843 (1865).

Layomys rerun, p. p. Fraas, Wiirtt. Naturw. .Taliresh. xxvi. p. 171 (1870).

Prolaffus Meyeri, Deperet, Arch. Mus. Lyon, iv. p. 12.3, pi. siii. figs. 18-18 f (1887).

Myoluyus sansaidensis, Filhol, Ann. Scienc. geol. xxi. p. 46, pi. i. fig. 8 (1891).

Lnyuniys [Prolagus) Meyeri, Deperet, Arch. Mus. Lyon, v. p. .t,j, pi. i. figs. 30, 31 (1892).

A^'hen publishing liis first note on Lac/oiiii/s-hke E,odents from ffiniagen (1S3G), H. v.

Meyer was not aware that two rather diffei-ent forms occur there ; he comprises them

both under the name of Lagomys ceningensis. Later on, in his Monograph of tbe fossil

Vertebrata from CEningen, he arbitrarily sets aside Konig's specific name for the smaller

form, for which he adopts a manuscript name by v. Tschudi, Lagomys Meyeri, found on

one of the labels, while he reserves the name Lagomys wnhigensis for the larger

form. As stated before, the same author identified the lagomorphine Ptodent from

Steinheim with the smaller form from ffiningen ; and in the sequel equally those from

several otlier Miocene deposits in Germany.

On the ground of Pomel's description of the Sansan species, Schlosser adds Lagomys

{Frolagi(s) sansaniensis, Pomel, to the synonyms of 3Iyolagiis Meyeri; and likewise the

Lagomyidte from the Spitzberg in the Ries, near Nordlingen (Bavaria), referred to

Ljagomys rents, Hens., by Fraas (1S70). Filhol has figured as Myolayus sansaniensis

(E. Lartet) the type-specimen, a mandilutlar ramus, of Lartet's Lagomys sansaniensis,

and is satisfied that " cette espece, comme on le verra par I'examen de la figure grosSie

que nous en donnons, etait tres differente de toutes celles qui ont ete deerites " *. It is

precisely this enlarged figure of the lower cheek-teeth which shows conclusively that the

Sansan fossil is one and the same with the Prolagus species from ffiningen and Steinheim,

as conjectured by Schlosser and confirmed by Deperet f, who has added La Grive-

Saint-Alban (Isere) %, Mont-Ceindre, and Gray § to the localities of this widespread

Middle Miocene species.

The following descriptions are based on specimens collected at La Grive-Saint-Alban

by myself.

In the genus Prolagus the molars are no longer rooted, and, with the exception of the

deciduous teeth, all the cheek-teeth grow from persistent pulps. It does not, however,

follow that the triturating surface preserves throughout the animal's life the same

pattern. This is the usually accepted belief 1| ; l)ut although the proofs to the contrary

* Ann. Sc. Geol. xxi. p. 47, pi, i. fig. 8 (1891 ).

t Arch. Mus. Lyon, v. p. 57 (1892).

+ Op. cit. iv. p. 167 (18fi7), V. p. r,C, ( 1S94).

§ Op. cit. V. p. 57.

II See, e. y., Giebel, in Bronu's ' Khn^en iind Onliumgen des Thierreichs,' vt. v. p. 15:.' {Is75), where he treats of

the Rodentia with laminated teeth (" Blatterziihiie "), including the Lagomorpha. He says of them: "Die

Kaufliichen dieser Zahne anderu ihre Zeichnung durch Abnutzung nicht."' He might have known better, at least

as regards the Hares, from what Hilgendorf had said ten years before (Monatsber. K. Prenss. Akad. d. Wissensch.

Berlin, 14 De/.. 1SC5, p. 673) respecting the upper grinding-teeth of young Hares.

63*

452 DR. C. I. FORSYTH MAJOR ON

tire not in all cases so evident, and so surprising at the same time, as in the group under

consideration, or as in Geomyidre *, or Kaplodonfia f , it is nevertheless a fact that neither

in Rodents nor in Mammalia generally is the surface of the crown absolutely identical

throughout its length ; although in many of them we may sj)eak of a relative constancy

of pattern.

Hensel, in the description of the upper teeth of Frolagns, has overlooked this

circumstance, and as a result has in one case wrongly interpreted the tooth-structure.

This occurs in the description of " Myolugus sardus ; " % but, since Fraas has endorsed

Hensel's error in his description of Prolagus a'ti/ngensis (Kon.) {'' Mi/olaffus Mei/eri") §,

which differs very little from the former, we shall have to deal with the argument in the

present description as well. How little both Hensel and Fraas n-ere aware of tbe change

of pattern depending on the age of the animal is shown by the way in which, for

convenience sake, they studied the tooth-crown. Hensel does not figure tlie natural

surface of attrition > but gives transverse sections of it ||; while Fraas declares % that it is

more convenient to examine the teeth from the inferior side, meaning the open alveolar

end of the shaft !

Fig. 21, PL 36, rejiresents the four upper grinding-teeth of Prolagus ceningensis in a

rather worn condition. Both the upper true molars, the fourth and fifth in the series,

those teeth which in Titanomys exhibit a beginning of reduction on the postero-external

side, have undergone in Prolagus ceningensis a considerable change as compared with

the same teeth in the former genus. Of the two more or less crescentic enamel folds

of Tikmomys, only one, apparently the inner, persists, in the foi-m of a very small

enamel islet in the posterior part of the triturating surface {b). The notch of the internal

side (ff) has been transformed into a transverse enamel fold, which, as we shall find to

be likewise the case in Lagomys and Lejyns, approaches the outer side of the tooth. The

enamel lining of the outer side, partially interrupted in the postero-external corner of

m. 2 of Titanomys, is almost entirely missing in the external border of both the molars

of Prolagus (and of its posterior premolar as well). In other words, the outer parts of

the crown, those which are the least affected by trituration, have degenerated in conse-

quence of disuse; and avc might be inclined to assume that com2)ensation has been

effected by the transverse fold penetrating towards the outer part. But this is not, to all

appearance, the exact explanation of the phenomenon. The tritui'ating surface in the

tooth of the young animal — in the part of the shaft which is the earliest formed — is

more square than in the adult ; in the latter, it presents the well-known narrow

transverse shape of the lagomorphine upper molar. If we remove one of these teeth

from its socket and examine it from the anterior or posterior side, it can be seen that,

* 0. Hurt Merriam, ' Monographic lievisioii of the Pocket Go[iliers, Family Geomyidai ' (North American Fauna,

no. 8), pi. 16 (1895).

t Proc. Zuol. Soe. Loudon, p. 70(i (1807).

+ Zeitschr. deutsch. geol. Ges. viii. pp. 690, 691 (1856).

§ Wiirtt. uaturw. Jahresh., xxvi. pp. 174, 17-^ (1870).

II " Die Baekenziihno siiid stets senkrecht zu ihrer Axe angeschliffen worden, daher sind die Abbildungen

eigentlich eine Aneiuanderreihuug der einzelucu Uuerschnitte " (I. c. p. 703).

^1 Oi>. fit. p. 173.

FOSSIL AND KECEXT LAGOMOllPHA, 453

while its outer border maintains tliroughou.t its height almost a vertical direction, or is

even concave, the inner part of the tooth slopes down medially, from below to above

(taking into account its natural position in the maxillary). The tooth, therefore, as it

continues to grow, extends persistently in a transverse direction ; but this growth takes

place chiefly, if not exclusively, towards the internal side ; so that the transformation of

the internal notch of the TUanomy s-iooih. into the transverse fold of the true molars

of Prolagus is not the result of its extension outward but inward. In other words,

new formation takes place in that part of the tooth where there is increased work,

•while the outer part — that which is scarcely or not at all affected by trituration — not

only remains stationary, but even becomes atrophic.

On the other hand, since in the more specialized forms, beginning with Prolagm

sardiis (PI. 36. fig. 24), the transverse enamel fold reaches almost the outer side in the

true molars, it is very possible, and even likely, that secondarily a slight extension

outicarcl of this transverse fold takes place; although the outer border of the tooth

is nearly lunctionless, its condition, almcst devoid of enamel, would nevertheless effect

a too rapid wear of the dentine if some compensation were not ensured.

The posterior of the three premolars, p. 1, situated between tlie first molar and the

second premolar, is intermediate in shape as in position. Both tlie crescentic enamel

folds of Titanomijs are preserved in this tooth in the shape of central enamel islets, a

much larger internal one {h), with an elongate tmterior horn, and a smaller outer

one (6') (fig. 21). The transverse fold {a) which opens on the inner side is much

shorter than in the molars ; it is scarcely more than an elongate notch. To put it

otherwise, as compared with the molars, p. 1 presents less reduction in its external jmrt,

and less new^ formation in regard to the transverse fold starting from the inner side.

Exactly the inverse is apparent when we compare p. 1 with the tooth in front of it.

This latter (p. 2) has triangular contours, with the apex internally, a shorter, slightly

convex anterior, and a longer posterior side ; as a consequence, its outer border runs

obliquely. In its pattern, this premolar strongly resembles the Titanomi/s-teeth ; instead

of a transverse enamel fold we find in it a short notch («) on the inner side, as

in Titaiioi)ii/s ; while almost the whole of the cro\\-n-surfaee is occupied by the two

crescentic enamel folds [b and t-), with an indication of a minute third one— equally

marked in Titanomys — on the antero-exterual corner. The latter is more distinct in

youu<;er specimens of Prolagiis (jeii'mijensis (PI. 36. tig. 10, p. 2). The enamel folds

alternate with crescent-shaped, pointed cusps.

On comparison of p. 2 witli p. 1 it becomes at once clear that the main ditference

between the two consists in the circumstance that the crescentic enamel folds in the

former have become reduced to the condition of enamel islets, their communication

with the antero-external margin of the tooth having ceased. AVhen describing p. 1 of

Frolagns surdm, in which, as a comparison of our figures shows, this tooth (fig. 24, p. 1)

is almost identical with its homologue in P. amingensis, Hensel labours under a strange

misconception. He says : — " Das Merkwiirdigste aber an dem Zahn sind zwei isolierte

Schmelzcylinder. Sie befinden sieh in dem ausseren und hiuteren Viertel des Zahnes." *

* Oj}. cit. p. 090.

454 DR. C. I. rORSTTH MAJOR ON

Aiter describing these enamel cylinders accurately, lie continues : — " Der Inhalt dieser

beiden kleinen Cylinder ist ganz gewiss Zabnbein, obgleicli eine mikroskopiscbe Unter-

sucliung nicbt angestellt werden konnte. Man sieht aber an dem Wiirzelende des

Zahnes die beiden Cylinder, sowie den ganzen Zahncylinder, hobl, dalier sie anch wie

dieser sich sjiater wobl mit Zaiuibein fiillen werden. Wir baben bier ein Beispiel einer

Zahnbildung, die bisber nocli nicbt beobacbtet wurde. Denn bier ist nicbt eine Ver-

einigung einzelner Cylinder zu einem Ganzen wie bei den sogenannten zusammen-

gesetzten Ziibnen, sondern eine Einscbacbteluug "[inclusion]" zweier einzelner Ziibncben

in einen grossen." *

It seems strange tbat so accurate an observer sbould not bave perceived at once tbat

the islets (" isolierte Scbmelzcylinder ") of p. 1 are the liomologues of the two enamel

folds which, on the preceding page, be had described in the anterior tooth (p. 2) ; and

that an enamel fold whose central part dips vertically, and deeper in the shaft of the

tooth than the peripheral, generally becomes by attrition reduced to a central islet This

is a phenomenon of the most common occurrence in teetli of all Mammalian orders.

Hensel's misconception is intelligible only from his apparently not being aware that

teeth growing from a persistent pulp, like the brachyodout teetb, though only to a

certain extent, are liable to changes in the pattern of their triturating surface.

As a matter of course the enamel islets of p. 1 are filled wath cement, as are the

enamel folds of the anterior tooth. Tlie argument adduced bv Hensel £?oes for notbim?,

as not only the dentine, but also the cement is always missing in the root-ends of these

teeth, both substances being not yet developed in these younger stages.

As mentioned on a preceding page, Fraas has endorsed Hensel's statements, when

describing the similar-fashioned p. 1 of J\ (rningensis. He is, besides, of o])iuion that

the deciduous teeth furnish the explanation of the conformation of p. 1 : — " Die

Betracbtung der Milchziibne wirf fc auf diese in der That von alien bekannten Zahnen

abweichende Bildungsweise ein Licht." f A supposed extraordinary j^benomenon calls

for an extraordinary explanation, and this be gives when describing the deciduous

teetb J. He means to say that there is a coimection between the roots and the enamel

folds, inasmuch as the cylindrical roots are included in (or l)y) the tube composing the

whole tooth, as it were, nested in it (" eingeschacbtelt ") — ^just as we should speak of

willow-boxes nested one into the other — the folds appearing on the surface of attrition,

according to this theory, being but the upper ends of the cylindrical roots ! The only

thing which the author thinks remarkable is the fact that the central folds, which are in

connection with the roots, are present as well in tlie permanent teeth which are devoid of

roots. At the bottom of this singular theory lies, first, the author's initial statement, to the

* Op. cit. p. 091. i Op. cit. ]i. 175.

X op. cit. pp. 177, 178. "Die Fait en. . . .die auf der Kauttiicho d cs Zalins zu Tage tret en sind nichts anderes,

als die oberen Enden der in die Zahnbiichse eingeschachtelten Wtrzelcvlinder. Sehen wir somit an den Mileh-

backenziihnen auf deren Oberfliiche Schmelzfalten zu Tage freten, wo die Wurzeln sich vereiiiigen, so begreift sicb

dieser raltenschlag leicht. Das Eigenthiimliche ist nur, dass .sich die inneren, mit den Wurzeln zusammenhangenden

Ealten adcli an den permanenten Zahnen zeigen. die viber ihre ganze Dauer wurzellos bind. Es ist diess, so zu

sasen, die Ucbertrasung eines Jugendzustandes auf das Alter. ..." etc.

FOSSIL AND EECENT LAGOMOKPHA. " 455

effect that the roots of the deciduous teeth of Prolagus have a coating of enamel : " sie

hesteheu geuau aus derselben Sehmelzmasse, wie die Zuhnbiichse selbst, die das Zahnbein

umg-iebt " *; and secoudly the fact that in some instances he seems to have mistaken

foi' roots what in reality are tlie tul)e-like lower terminations of the enamel folds.

In the first tooth of the ujjper series (p. 3, PL 36. fig. 21) the two enamel folds are

also present ; they penetrate into the surface of the crown from its anterior side

and run in a longitudinal direction. The anterior liorder ('• wall ") of the triturating

surface, already sliglitly shortened in p. 2, is still more shortened in p. 3, being reduced

to a short longitudinal stump on the antero-internal corner.

From what has previously been stated, we are prepared to find, in different stages of

attrition of these upper teeth, some difference in the pattern ; this is, in fact, what takes

place. The enamel islet of m. 2 has disappeared in old specimens ; and such is the case in

the specimen figured by Fraasf. The enamel islet of m. 1 varies in size according to

age, being larger in younger specimens. The same holds good with regard to the two

enamel islets of p. 1. We anticij)ated tliat in young stages of this tooth the enamel

islets wouhl have the shajie of enamel folds ojieuing freely on tlie margin of the tooth,

as is the case in p. 2. This is, in fact, what happens in young specimens of the following

species [P. sardus). Of P. a'ltingeims I have no very young examples.

P. 2 varies little with age; the notch on the inner side is more distinct in comparatively

young individuals, and there is shown in this stage (fig. 10) a third very small enamel

fold in the postero-external corner of the tooth, which soon disappears by attrition.

Deciduous upper teeth ofV. oeningensis. — Fraas has figured the three deciduous upper

cheek-teeth iji. situ J ; he scarcely describes their pattern, contenting himself with the

statement that the anterior one is well provided with folds (" faltenreich "), and that it

presents much resemblance to the second of the permanent dentition §.

I have only detached upper deciduous teeth, five in number. Two of these are in the

British Museum, under M5237, from my collections. The anterior milk-tootli (d. 3) is

not represented among these five detached teeth ; according to tlie figure of Fraas, and

to what I know of the same tooth of P. sard/is, it has triangular contours ; while the

detached teeth at my disposal arc squarish ol:)long, almost tetragonous, their transverse

diameter slightly exceeding the longitudinal. They show (PI. 36. fig. 29) an internal

notch and two enamel folds, the latter opening freely on the outer side. The internal of

the tw^o folds (b) has the form of a crescent and is the larger of the two. The roots

are three in number ; the outer two very minute, the inner single one considerably

larger ; the former run jjarallel with each other, hut not wdth the odd inner root, whicli

strongly diverges from them inward, while tiiey diverge outward (PI. 39. figs. 21, 22).

Prolagus sakdus.

Ldyoniys sardus fossilis, Riul. Wagner, Okcii's Lsis, \). 113G (1829).

Lagoinys foss'dis. Id. op. cit. jj. 1139.

* In this there is some trutli ; see above, pp. 446, 447.

t Op. cit. pi. ii. iig. 6. + Op. cit. pi. ii. fig. 14. § P. 177.

456 DR. C. I. FOESYTII MAJOE OX

Lagomys corsicanvs, Eud. Wagner, op. cit. p. 1139 ; Giebel, Fauna d. Vorwelt, i. p. 99 (1847) ; Gervais,

Zool. et Pal. franc., first ed. p. 32 (1848), second ed. p. 50 (1859); Lortet, Arch. Mus. Lyon, i.

p. 53, pi. 8 (1873).

Myolagus sardus, Hensel, Zeitschr. deutsch. geol. Ges. viii. p. 695, pi. xvi. figs. 7, 8, 11 (1856) ; Forsytli

Major, Atti Soc. Ital. Milauo, xv. p. 390 (1873) ; id. Kosmos, vii. (vol. xiii.) pp. 6, 7 (1883).

Lagomys (Jlj/o/agus) sardus, Schlosser, Palfeontogr. xxxi. p. 29 (1884).

Lagomys sardus, Lydekker, Cat. Foss. Mamm. Brit. Mus. i. p. 256 (188.5), v. p. 325 (1887) ; Schlosser,

Pal. Oestr.-Ung. viii. p. 86 (1890).

This Pleistocene species, which is somewhat larger than its Middle Miocene forerunner,

closely resembles the latter in its nppcv molars, as the comparison of the figure shows.

However, the specialization of the true molars has progressed, for in the teeth of the

adult no trace remains of the two crescentic enamel folds (PL 36. fig. 24). P. 1 agrees in

the two species. P. 2 is scarcely different in either ; the enamel folds in p. 2 of the adult

Trolagus sardus are slightly reduced in size, and the larger inner fold {h) is, in old

specimens, sometimes shut out from the outer border by intervening dentine (fig. 24, p. 2).

P. 3 has its anterior " wall " somewhat more developed than in Frolar/us ceningensis.

Of this species I have collected a good number of young specimens. The examination

of yoimger stages of the teeth is of considerable interest, as they recall, more than the

adult teeth, the primitive features of the TlUmomys-iy^Q.

Pirstly as to p. 2, This tooth, being the most conservative, shows, as might have

been anticipated, the least change from young to old. The diminutive postero-external

enamel fold, however, which we met with in a moderately young specimen of P. cenin-

gensis, is visible only in very young individuals of Prolagus sardus.

P. 1, as has been intimated above, exhibits in the young stage a close approach to p. 2 ;

the tw^o enamel folds are not yet reduced to the shape of islets, but open freely on the outer

side of the tooth (PI. 36. fig. 11) ; the only appreciable difference, apart from its squa,re

outline, consisting in this, that the crescentic cusj) (6) wdiich divides the two enamel folds

has its anterior horn less produced otttward, so that the folds unite in a common delta

on the outer side. The next stage of the still young p. 1 (fig. IG) is the pattern we met

with in old p. 2 ; the small external enamel fold (c) alone opens on the outer side, while

the larger internal fold has been reduced to the shape of a crescentic islet {b). The

third stage is that of the adult, the external fold likewise having become an islet (fig. 24).

It might be expected that very old specimens of p. 1 Avould show the complete dis-

appearance of the islets, as is the case in the true molars ; this condition I have never

found in Prolagus sardus, although I have had the opportunity of examining more than

a. hundred upper jaws. But it occurs in a Pliocene form of Continental Prance

(Koussillon), of which more will l^e said hereafter.

In the yomigost stages of the anterior true molar (fig). 4, in jaws which still jireserve

the deciduous dentition, remains of the two enamel folds are still visible ; they are very

imperfectly divided by the last trace of the once powerful intermediate cusp. In a

slightly more advanced stage (PL 36. fig. 10 (m. 1), one or two diminutive enamel islets,

situated postero-externally to the internal end of the transverse fold, are the last vestiges

FOSSIL AJND EECENT LAGOMOKPHA. 457

of the enamel folds of m. 1. In rare cases, very young m. 2 likewise show at the same

place a diminntive circular enamel islet, fig. 16 (m. 2).

The deciduous teeth (PI. 36. fig. 4) are scarcely different from those of the preceding

species ; but in these teeth also the crescentic cusj) " 6 " does not completely divide the

two enamel folds. D. 3 is triangular; d. 2 in younger stages somewhat approaches to

a triangular contour.

Pkolagus LOxoDrs (Gerv.).

Lepus sp., Gervais, Zool. et Pal. Fr. 1' eil. i. p. .'52 (1818).

Lepus loxodus, Gervais, ib. ii. explic. pi. xxii., pi. xxii. fig. 9 (1848-52).

Lagomys loxodus, Gervais, Zool. et Pal. Fr. 2' ed. p. 50 (1859) ; id. Zool. ct Pal. geu. p. 148 (1867-69).

? Lagorivjs {Prolagus) corsicaniix, Deperet, M(>m. Soc. Geol. France, i. p. 56 (1890), iii. p. 122, pi. xii.

figs. 1, Iff (1892).

'iMyolagm elsanus, Forsytli Major, Atti Soc. Tosc. So. Nat. i. p. 229, 238 (1875), &c. {vide infra).

Gervais' Lagomys loxodus has been a stumbling-block for fifty years, owing, as I

think, to the circumstance that the pattern of the four posterior right upper cheek-teeth

preserved had not been grasped and was incorrectly represented. An inspection of the

original specimen would at once settle the question; but since I am not acquainted with

the original, I must deal, as best I can, with the pul)lished figure and Gervais' incom-

plete description.

The figure is four times natural size. Gervais' desci'iption runs as follow^s: — "DifFere

des Lagomys actuels et diluviens par la forme ovalaire et sublosangique des doubles lobes

de ses seconde a quatrieme molaires superieures ; la molaire anterieure est en meme temps

plus forte, et elle a ses replis plus compHques ; — taille sensiblement inferieure a celle du

Lapin de Garenne"*. It was found in the town of Montpellier, in the fluviatile

Pliocene marls f. At the same locality, under the Palais de Jiistice, was found the

Semnoplthecus monsjjessulamis; and this circumstance is of imjiortance, as proviu"-

that these fossils belong to the older of the two faunas, mixed together under the

designation Montpellier. SemnopithecMs occurs also in the Lower Pliocene of Casino

(Tuscany).

The reason for which Gervais considered the teeth to be the first, second, third, and

fourth is obvious ; the last in the series is equal in shape to the penultimate, Avhile in

Layomys the last molar has a postero-internal apjjendage. I believe them to be the

second, third, foiu'th, and fifth (p. 2, p. 1, m. 1, m. 2) of a species of Prolagus, because the

anterior tooth has the characteristic triangular outline of p. 2 of Prolagus, with the apex

turned inward [cf. pi. 36. figs. 10, 21, 24, p. 2). In further agreement Avith Prolagus,

Gervais' figure of this tooth exhibits on the outer side two enamel loops ; on the inner,

one. The more minute features of this tooth, as well as of those following behind, were

not recognized, and therefore the latter have been represented in the manner in which

lagomorphous upper teeth generally were and still are, founded on the belief that they

are composed of two distinct lamellce closely connected.

In my opinion there is not the slightest doubt left that we have to do with a species

* Zool. et Pal. Fr. 2" cd. p. 50. t L. c.

SECOND SERIES. — ZOOLOGY, VOL. VII. 64

458 DE. C. I. FORSYTH MAJOE ON

of Prolagiis, and I feel sure that a close examination of the fossil, if it still exists in the

Museum of Montpellier or elsewhere, will confirm my view.

It remains to enquire whether there is some reason for identifying it with one of

the species of Prolagus found in deposits contemporaneous, or approximately so, with the

strata of Montpellier in question. Of these there are two: (1) Prolagus {Myolagus)

elsanus, which I have mentioned from the lignites of Casino, in the Val d'Elsa, Tuscany ;

and (2) " Lagonnjs [Prolagus) corsicanus" described under this name from E,oussillon by

Deperet *. The little I have to say of the former will he stated in a separate paragraph

hereafter.

As to the latter, Deperet declares that it agrees in size as well as in all other characters

Avith the Prolagus from Corsica and Sardinia, and he therefore describes it under the

above name. This proceeding is as it should be ; so long as no differences are traceable

between both there is no reason for two specific names. But, so far as my own

(ixperience goes, the circumstance of a mammalian species surviving unaltered from the

Lower Pliocene to the present era (I have found calcified remains of Prolagus sardus,

var. cors'wamis, in an "abri sous roche" of the Neolithic period in Corsica) would be

quite unique, and it is a priori highly improbable, even taking into consideration that

insular species may become, up to a certain extent, conservative in their character. I

therefore incline towards the belief that hereafter characters distinguishing the Houssillon

from the island form will be shown to exist.

The presence of a third lower molar, supposed by Deperet to appear occasionally

in the Roussillon fossil, would be such a distinctive cliaracter, since it has never

been observed in the Pleistocene species ; but I give further on (pp. 482, 483) what I

hold to be tlie real explanation of the fact noticed by Dcp6ret, viz. that the supposed

m.. 3 in certain jaws from Roussillon is simply a portion of m. 2, which has been

cicciden tally detached.

Another cliaracter noticed by Deperet in the Ptoussillon species deserves mention here,

[n the specimen from this locality first described f it was stated that the three posterior

upper cheek-teeth are similar to each other, being " construites sur le type ordinaire des

Leporid6s." In the third volume of the ' Memoires ' a second specimen is described % ;

in this the " premiere arriere-molaire " (p. 1) differs from the same tooth of the first

specimen by " exhibiting on the surface of its posterior lobe a double chevron-shaped

enamel fold, recalling the molars of Titanomys. These folds must disappear rather

rapidly by effect of trituration, thus explaining their absence on the specimen previously

figured, which apparently was more adult." Dej)eret adds that these chevron-like folds

exist equally in the corresponding tooth in the specimens of " Lagomys corsicanus "

from Bastia (Corsica), although this character is not represented in the figure of the

latter published by Lortet §, and he concludes that the above is a complete confirmation

* Ch. Deperet, " Animaux plioci'nes du Rous.sillo:i," Jlt'in. !Soc. Gi'ol. France, i. p. 50, pi. iv. figs. 27-^5 (1S90) ;

lii. p. 122, pi. xii. figs. 1, 1 (( (1.SU2).

t Mom. Soo. Gcol. Frauee, i. p. 57 (1890)..

X. Op. cii. iii. p. 122, pi. xii. figs. 1, 1 a (lS92j.

§ Arch Mus. Lyou, i. pi. viii.

FOSSIL AND EECEjVT LAGO^MOEPHA. 459

of the identity of the Corsican and Sardinian fossil with tlie Pliocene animal from

Roiissillon.

1 venture to siiggest that the inverse conclusion may he drawn from these statements.

The character in question has been figured and exhaustively descinhed in the preceding

pages. Of Frolagus sanlus, I have represented on PL 36. three stages. Fig. 11 shows

p. 1 of a young individual in which the two enamel foldings {b and c) are large and

confluent on the outer margin. In tig. 21 (p. 1 from an adult and rather old individual),

they are seen to be separated from each other and reduced to the shape of central

enamel islets. Fig. IG exhibits an intermediate condition (see p. 456). If these

chevrons are not represented in Lortet's figure quoted by Deperet, this is due to an

inadvertence of the artist ; for an examination of the figure quoted shows that the

artist had seen something of the kind, but omitted to represent it accurately. In the

vast number of maxillaries of Prolaf/us sarcitis from Bastia and various Sardmian

localities which have passed through my hands, I have never missed the presence in

p. 1 of the two enamel folds ; but it is possible that they may disappear in very old

individuals. The fact that, of the only two specimens from Roussiilon examined, this

cliaracter was absent in one, proves in my ojiinion that the Roussillon species, although

geologically older, has exceeded the island species in the transformation of the cheek-

teeth, thus representing the last stage of Prolagiis ; /. c. that which approaches closest

to the condition shown by p. 1 of Lagopsis and LagonnjH.

The peculiarity which 1 am about to mention in the anterior lower premolar of the

Frolagus from Casino is not recorded l)y Deperet in the lower p. 2 from Roussillon ; but

it would be worth while to re-examine this tooth in the specimens from the latter place ;

for the two Prolagi from Roussillon and Casino may be identical, if we judge from the

association of other identical species in the two localities. The same may be said of the

fossils from Roussillon and Montpellier ; but the information concerning the Frolagus

from the latter locality at present at our disposal is insufficient for close comparison with

other fossil forms.

Prolagus elsanus, Maj.

Myolayvs elsanus, Forsyth Major, Atti Soc. Tosc. Sc. Nat. i. pp. '220. ,2.38 (1875) ; id. in L. Riitimeyer,

Ueber Pliocen und Eisperiode auf beiden Seiten der Alpeii, p. 15 (187()) ; id. Atti Soc. Tosc. Sc. Nat.

Proc. Verb. p. xc, ] 1 jMaggio 1879.

A few fragmentary mandibular rami from the Lower Pliocene lignites of Casino, Val

d'Elsa (Tuscany), preserved in the Pisa Paloeontological Museum, have been long ago

noticed by me, and I have on various occasions stated that, by the conformation of their

lower anterior premolar (p. 2), their reference to Hensel's genus Myolagus {Frolagus) is

beyond doubt. As at the time no species of Frolagus had been recorded from the

Lower Pliocene, I felt justified in assigning a new specific name to the Casino fossil.

Of some importance, not only as distinctive for the species, is the following character

not previously recorded by me, but of which I was perfectly aware at the time, for it is

shown in tuo sketches which I made of the lower anterior premolar, right and left,

presumably of the same specimen. At the postero-internal margin of tbis p. 2 is a

64*

i60 DE. C, I. FOESYTH MA JOE ON

narrow enamel fold — more distinct in the left-hand tooth — corresponding to a shallower

and wider fold in Tltanomijs, which forms the anterior houndary of a minnte terminal

cusp, marked " t" in the figures {Titanomys, PL 37. figs. 2, 3, 7, 2.5). More ahoiit

the significance and the homologies of this terminal cusp will he said in the chapter

treating of the lower cheek-teeth. I mention it here, since in no other species of

Prolagus have I met with it in p. 2, and it may therefore be characteristic of Pmlmjus

elsamis.

The only teeth known from Casino are mandibular ; and as tliose from Montpellier

are maxillary, no direct comparison can be made between them. Both deposits are

contemporaneous, and bear other species in common; wherefore there are good grounds for

assuming the specific identity of the remains of Prokujus from the Italian with those of

the Prench deposit. If this can be satisfactorily shown in the sequel, Gervais' specific

name will have to replace mine on grounds of iiriority.

3. Genus Lagopsis, Schloss.

Lagopsis verus (Hensel).

Lagornys wningensis, H. v. Meyer, Neu. Jahrb. 183G, p. 58, p. p. ; id. Foss. Saugethiere &c. vou CEniugeii,

p. 6, pi. iii. fig. 1 (1845) ; Biedermann, Pcti-efacten aus d. Umgeg. v.Wintertliur : II. Die Brauiikohleii

von Elgg.p. 13, pi iii. figs. 1, 2, 3 (1863) ; Lydekkcr, Cat. Foss. Mamin. Brit. Mus. i. p. 256 (Specim.

Br. Mus. nos. 42815, 42816 (?), 42820 (?) (1885).

Lagmnys verus, Hensel, Zeitschr. deutsch. geol. Ges. viii. ]). 688, pi. xvi. figs. 12, 13 (1856) ; Deperet, Arch.

Mus. Lyon, iv. p. 164, pi. xiii. figs. 16, 17 (188/).

Titanomys mningensis, H. v. Meyer, Palseontogr. xvii. p. 228 (1870), p. p.

Lagomys {Lagopsis) wningensis, ScMosser, PalaeontogT. xxxi. p. 31 (1884), p.p.

Lagornys [Lagujtsis) verus, Sclilosscr, op. cit. p. 31, pi. xii. figs. 40, 46, 49 (1884) ; Deperet, ArcL. Mus.

Lyon, V. p. 57 (1892), p. p.

Hensel's type-specimen is a mandibular ramus, and will therefore be more fully

discussed in a later chapter. He was impressed by its approaching much nearer the

recent Lagomys than the remains of Prolagus [''Myolagus") described in the same paper.

■' Ich nenne die Art Lagomys verus, weil sie sich durch die Zahl ihrer funf Backenzahne,

durcli die Stelluug des Eoramen mentale iind durch den ersten unteren Backenzahn, der

uui- aus einem Cylinder besteht, als ein achter Lagomys ausweist " *.

It is perfectly triie that this fossil is closely related to Lagomys. However, Schlosser

proposed to raise " Lagomys oeningensis, H. v. Mey.," and " Lagomys verus, Hens.," to the

rank of a genus, Lagopsis, a position with which I in general agree, while I disagree in

part with the reasons assigned for it. There is no doubt that some of the larger Lagomyidse

of QEningen, which were comprised by H. v. Meyer under the above name, are identical

with Hensel's Lagomys verus ; but with regard to other specimens this has not yet

been demonstrated. We cannot therefore throughout regard " Lagomys aiiiliigeusis,

H. V. Mey.," as synonymous with " Lagomys verus, Hens.," as Schlosser has hesitatingly

assumed in his ' Nager des europ. Tertiars ' (p. 32) and more positively asserted later f,

followed by Lydekker %.

* Op. cit. pp. 688, 68'J. t Beitr. Pal. Oestr.-Ung. viii. p. 86 (table) (1890).

t Cat. Foss. Mamm. Brit. ilus. i. p. 256 (1885).

FOSSIL AND KECENT LAGOMOEPHA. 461

Schlosser bases his new genus Lagopsis on the differences (froua Layomys) in the shape

of the anterior lower premolar (p. 2), " und das, wie es scheint, haufige Fehlen des vierten

Molaren," thereby meaning the lower m. 3. I agree with the first proposition; as to the

latter, it will be shown later on that in all the specimens of Lagomijs verus, in wliich

m. 3 is missing, it has simply dropped out, for its alveolus is present.

The upper teeth of Lagopsis, which are here described for the first time, although more

closely resembling Lagomys than Prolagus, present, however, characters which strengthen

the conclusion based on the lower teeth, viz. the establishment of a separate genus.

Lagopisis realizes the penultimate stage in the evolution of the cheek-teeth of Lagomyidse,

Lagomys the last.

The description of the upper cheek-teeth of Lagopsis may be appropriately preceded by

that of Lagomys *. The numerous existing species of Lagomys show a considerable

constancy in the pattern of their cheek-teeth. Young individuals were not available to me.

In the adult we find a further step away from the Titanomys type ; not only the two true

molars, but the posterior premolar (p. 1) likewise, have lost every trace of the crescentic

enamel folds, so that p. 1 has become very similar to the true molars, all three showing

the transverse fold proceeding far outward. P. 2 exhibits, in a very interesting manner,

a reduction of the Titanomys tyj)e. There is no transverse fold, the original internal notch

being maintained ; of the tAvo crescentic enamel folds (/;) and (e) only the former,

the internal, remains, and it bears on its outer side a strong cusp (6) and opens on the

antero-external margin of the tooth. P. 3 shows a further reduction as compared -with

Prolagus. Of the internal notch only a feeble vestige is visible, and of the two typical

enamel folds only the internal one, which runs obliquely from the middle of the anterior

margin in a postero-external direction.

Deperet has figm-ed from La Grive a left palate devoid of teeth, but exhibiting very

distinctly the alveoli of the five cheek-teeth ; he assigns this fossil, quite rightly in my

opinion, to Lagopsis verus f .

Among the fossils collected by myself at La Grive are tAvo rooted upper cheek-teeth

(Brit. Mus., G. D., No. 5264), which in size agree with the lower teeth of Lagopsis

verus from the same deposit. Lagopsis being the one Tertiary genus Avhich, by the form

of its lower teeth, comes nearest to Lagomys, it covild be anticipated that the upper teeth

of the fossil would likewise show a near approach to the recent genus, and this is,

in fact, the case. Additional evidence is furnished by a specimen from CEningen, to

be described later on.

One of the isolated teeth just mentioned, from La Grive (PI. 36. fig. 31), exldbits the

same somewhat triangular outline — the apex being turned outward — and about the same

characteristic enamel folding (6) as the upper p. 2 of Lagomys. In the p. 2 of LMgomys

the outer enamel border of the crescent {h) is raised into a strong triangular cusp, with its

convexity turned inward ; in the fossil tooth the inner border of the crescent is raised in

the same manner. From p. 2 of Prolagus oeningensis (Kon.) (PI. 36. fig. 21) the tooth

* Enlarged horizontal sections of the u^jper cheek-teeth of Lar/omi/s aJpinni, and L. nejialaisis are given by Heusel,

op. cit. pi. xvi. figs. 1 & 5.

t Ojo. cit. p. 164, pi. siii. fig. 17.

462 UE. C. I. rOESTTH MAJOR ON

figured in fig. 31 can at once be distinguished ; the former is much smaller, has a tri-

angular outline with the apex turned inward, and a smaller enamel crescent (c), smaller

than, and external to {b). The upper teeth of Titanoijii/s Fontannesi, which in size

come nearer to the original of fig. 31, though slightly smaller, are provided with roots,

and they present other differences which have already been described. Prom its

resemblance to Lagomys this tooth (fig. 31) can therefore with certainty be determined

as belonging to Lagojjsis vents. The second of the isolated teeth before mentioned, from

LaGrive (PI. 36. fig. 32), agrees in size with the first; and for this reason alone Prolagiis

ceniiigensis can be excluded. It is either p. 1 or m. 1, if we judge from its agreement

Avith the corresponding teeth in Lagomys.

In the Palaeontological Collection of the British Museum (No. -12815) is preserved a

slab from ffiningen, showing the skeleton, " in a much crushed and imperfect condition,"

of a lagomyid Rodent, which Lydekker has determined as Lagomys amingensis, H. v.

Mey., because it agrees very closely in size with that figured by H. v. Meyer on pi. iii.

fig. 1 of his ' Possile Saugethiere von (Eningen ' *. On examination of this specimen

(No. 42815) several cheek-teeth are seen in a fragment of the cranium, presenting their

inner sides, the bone being here broken away. The lower parts of these teeth, in tlie

neighbourhood of the crowns, as Avell as these, were hidden in the matrix when the

specimen came into my hands. By carefully removing the matrix, the triturating

surfaces of the three anterior cheek-teeth (the three premolars) uere l;nd bare, and

it became at once apparent that this fossil is a Lagopsis.

It w^as too late to have the teeth figured in the present memoir, so that I must

content myself with their description. I give figures of them elsewhere t- The posterior

of the three teeth (p. 1) exhibits the pattern, which is shown by the homonymous premolar

of Lagomys and by the latter's two true molars. On the outer side of this tooth is a

shallow and open groove, which, so far as can be made out under a strong lens, has no

enamel border. Prom the middle of the inner margin a lozenge-shaped narrow enamel

fold [a of my figures in PI. 36) runs transversely across two-thirds of the breadth

of the triturating surface towards the outer side ; the posterior enamel border of this

fold is raised into a strong crest, running parallel with the anterior enamel border of

tbe tooth, both presenting a slight convexity turned anteriorly. The enamel fold is

filled with cement in its outer narroAver portion, its wider internal ojiening being devoid

of this substance.

The pattern of the middle premolar, p. 2, proves that the isolated tooth from La Grive

(PL 36. fig. 31) has been rightly determined as p. 2. As in the latter and in Lagomys^

there is only a comparatively shallow internal enamel fold {a) jiresent in the tooth

from CEningen, the greater part of the triturating surface being occupied by the enamel

crescent {h) before described in the tooth from La Grive. Outside the crescent (i)

appears a small enamel ring filled, like the latter, with cement ; this ring is doubtless the

vanishing homologue of the outer enamel crescent [c) of T/^^'«o;«y.s and Pro^^^MS, described

in the preceding pages and figured in PI. 36. In the La Grive specimen (fig. 31) there is

* Catalogue of the Fossil Mammalia iu the British Museum (Natural History), i. p. 250, No. 42815 (1885).

t Geol. Mag., dec. iv. vol. vi. p. ;J70, figs. 1 & 2 (1890).

FOSSIL AND EECENT I-AGOMOEPHA. 463

a mere vestige of some such element in the same place, the tooth beinj^ presumably

more worn than that in the CEuingen specimen. As in the La Gvive tooth, that from

ffiningen has both enamel margins of crescent {b) raised into triangular cusps, with

the convexity turned inward.

The anterior premolar, p. 3, of the CEningen fossil is not dissimilar to the same tooth

of Prolagus amingensis (Kon.). Whereas in recent Lugomijs the triturating surface of

p. 3 exhibits only one enamel fold — starting from about the middle of the anterior

margin and running backward obliquely, i. e. postero-externally — the same tooth in

Lagopsis shows two enamel folds, as in l?rolagus (eningensis, opening on the anterior

margin, and thence running almost straight backward.

These differences from. Lagomys strengthen, therefore, Schlosser's opinion, that the

Miocene fossil is to be considered as a genus [Lagopsis) distinct from Lagomys. At the

same time they present a further link in the gradual transformation of the tooth-pattern

{Tltanomys — Prolagus — Lagopjsis — Lagomys — Lepiis), which begins in the hindmost

molar of Lagomyidae and, gradually proceeding forward, stops at p. 1 in Lagopsis and

Lagomys, and at p. 2 in Lcpxis.

Genus Lepus s. 1.

It would seem more rational to treat of the Miocene Fal<Bolagiis before Lepus, since

there are strong reasons for the assumption that the former is the ancestor of the latter.

On practical grounds, however, I tliink it more advisable to give the description of

Lepus first, because we can fully understand tlie dentition of Palceolagus only after

having dealt with the dentition of the young of the existing genus ; and because, ou the

other hand, the latter exhibits a further development of the modernization initiated by

Titanomys.

Hensel, writing in 1856, stated that, contrary to the usual descriptions of authors, the

upper molars of Lepus consist each of a single cylinder, which in the second, third, and

fourth teeth is provided with a deeji enamel fold, filled with cement and penetrating

from the inner side*. When contending that all the previous writers on the subject

had incorrectly interpreted the conformation of the leporine molar, Hensel could

hardly have guessed that 43 years later he might have made an almost similar

complaint. We continually meet with descriptions and figures of lagomorphous animals

in which the upper molars are represented as formed by two cylinders closely united or

soldered together, presenting three transverse enamel ridges !

As compared with the Lagomyidtu, by the presence of m. 3 in the maxillary, Lepus

exhibits a more primitive condition. In the characters under consideration, however,

Lepus is undoubtedly the extreme member of the series. While in Lagomys the j)Osterior

premolar (p. 1) has alone acquired the transverse fold of the true molars, in Lepus

(PI. 36. fig. 33) p. 2 has been transformed as well. P. 3 alone retains what we may fairly

consider to be the ancestral enamel folds, as well as the ancestral internal notch. There

is no anterior " wall " ; wherefore the enamel folds open freely on the anterior side.

* Zeitschr. deutsch. geol. Ges. p. GSl (IboO).

464 DE. C. I. rOESTTH MAJOR ON

In a skull of L. nujricolUs from Ceylon (B. M. Z.D. No. 81.4.29.7) (PL 36. fig. 34) I

find that the modernization has l:)egnn to invade p. 3 also ; in the tooth of the right

side the internal notch {a) has assumed the shape of a lengthened fold, stretching half-

way across the crown and provided with plications as in the other molars.

M. 3 of Lepns is a small, vanishing cylindrical tooth ; in rare cases, however, of

L. eurojjcens a transverse fold has been observed in this *.

Now as to the condition of the teeth in the young of Lepus. Hilgendorf stated long

ago f " that the upper cheek-teetli of young Hares are jirovided with a crescentic enamel

tube, which forms a transition to the fossil Ilyolayus." This is perfectly true, but it is

not all.

In the Rabbit Oryctolagus cunicuhis, the two posterior upper deciduous teeth when

worn, and the permanent molars when slightly abraded (PL 36. fig. 5), exhibit a pattern

identical to that presented by the two anterior true molars of PalcBolagus, as figured in PL 36,

fig. 36, viz., an internal notch and a central crescentic enamel fold. Before attrition has

set in, they exhibit besides a strong crescentic cusp (6), which delimits the outer side of the

enamel fold (fig. 1). On the outer side of the cusp is seen a minute and shallow enamel

fold, incompletely dii-ided into an anterior and a posterior part by a ridge descending from

the middle of the outer slope of the cusp (c, figs. 1, 5). In d. 2 the anterior horn

of the larger crescentic enamel fold stretches further outward than in d. 1, and almost

reaches the outer border of the tooth. When attrition is going on, the shalloAver outer

fold may be seen for a short while on tlie triturating surface, under the form of one or

two minute enamel islets, which are soon completely Avorn away. The deeper inner

crescentic fold {b), apparently that mentioned by Hilgendorf, persists longer.

Here then we still meet with, in an epliemeral condition, the elements constituting the

Titanomys-tooih. : two enamel folds {b nnd c) separated by a strong cusj) (6) and an

internal notch («). The deciduous teeth of Leims s. 1. are cast olf without presenting

any other change except that produced by furtlier wear (fig. 26). In the permanent

teeth (PL 36. fig. 17) the internal notch begins to extend. That this growth takes place,

in these initial stages at least, wholly in an inward direction — by a prolongation of the

two internal cusps, which have gradually been transformed into transverse lobes % —

becomes evident when Ave compare these teeth before attrition and in a moderately

worn condition. In the former stage the crescentic fold is separated from the internal

* Hilirendorf, in Monatsber. K. preuss. Akad. der Wiss. Berlin, 14 Dec. Ifi65, \). 073. t Und.

X " 8 " and " 9 " in the iigures of all the upper cheek-teeth on Pis. 36, 37, 39. The scarcity of my material

prevents me from entering into particulars with regard to the young stages of other recent Leporidas, In a slightly

abraded p. 2 of Caprolagus hispidus (PL 36. fig. 27), h and c surround almost completely the well-developed

cusp (6) and unite together to form a common outlet on the antero-external side of the tooth. The enamel

exhibits numerous secondary plications characteristic of the teeth of this Hare. In the deciduous teeth oi Syhilagus

brasiKeiisis (PI. 38. fig. 20), a and b are united and present the pattern of a branched fork, visible also in

young stages of permanent teeth : in the latter (?<), represented by the two branches of the fork, soon disappears

from the triturating surface. In the true Hares, Lepus s. str. (PI. 36. figs. 22, 2-5, 2!S), the primitive pattern is

more ephemeral still than in the Eabbit ; the enamel crescent {h) is quite superficial. As is generally the case in

disappearing structures, these vanishing elements present a considerable amount of variation in diflFercnt specimens

of the same species.

FOSSIL AND EECENT LAGOMOEPHA. 465

notch only by a longitudinal enamel ridge ; in the latter it is still in its place, while the

internal notch has grown into a transverse fold stretching across half the transverse

diameter of the triturating su.rface *.

Upper Incisors of Leporidse.

The upper incisors of several Leporida^ present some little-known peculiarities.

In his description of Lepns nUjricollis, G. R. Wateriiouse says : — " The upper incisor

teeth have each two longitudinal grooves, placed very closely together, and not very

distinct"!. About the same statement is made with regard to Lepm yarkandensis,

Giinth., by Biichner, who believes this to be a special character of the species : — " Sehr

characteristisch fiir Lepiis yarkandensis ist der Bau der oberen Nagezahnc, durch VFclchen

diesc Art sich, wie es scheint, von alien Gattungsgenossen uatcrscheidet. Die

Vorderfiache des oberen Eackzahnes weist uamlich zwei iiache, schwach markirte

Binnen auf ; dieselben verlaufen dicht neben einandcr auf der inneren Halfte der

Vorderfiache" %.

I have before me the type-specimen of L. yarkandensis, Guuth. (Br. Mus. Z. D. No. 75.

3.30.10) ; an examination of the outer surface of its upper incisors shows but one

groove, as in other Leporidte ; the groove is filled with cement, but only incompletely,

so that the outer and inner border of the zone of that substance is marked by two

longitudinal strisB which somewhat simulate grooves. There is besides a median

superficial depression of the cement layer, so that the appearance of three longitudinal

grooves is produced. (In Caprolagus hispidus the median hollowing of the cement is

more accentuated.)

In L. niyricollis, as a rule, the appearance of two grooves is j)i*oduced by the same

cause as in L. yarkandensis. Sometimes, howevei", there is in the former species

a very sliallow longitudinal groove in the enamel, to the outside of the principal

groove filled with cement ; the lormer is somewhat more distinct in the unique skull

of a specimen from Ceylon in the Br. Mus. (Z. D. No. 81.1.29.7).

The fact of the presence of cement in the groove having been overlooked has given

rise to another misunderstanding. Wuterhouse says that in Lepus ruficaudatus the

* According to Pure Heude, the anterior upper premolar, p. 'A, of Lepus is composed of p. 3 ami a more anterior

premolar, which latter is said to be represented by the median of the three anterior lobes (" 6 " of my figures) of p. 3.

{op. cit. pp. 03, 64, pi. xiii. figs. 4, 5, 7, 189S). As I believe to have satisfactorily demonstrated — although not,

perhaps, to the Kev. Pore's satisfaction — that this '• 6 '" of p. 3 is tlio homologue of " (i " in the posterior premolars

and true molars of all Lagomorpha, I think we can, for this reason alone, dismiss the fusion theory, since each of

these posterior teeth woidd have to be considered also as a compound of two. (Similar remarks apply to p. 2 of the

lower jaw of Lepus, which, according to Pere Heude, is = p. 2 + p. 3.) I may add here that I have never observed

in the upper molars or premolars oi Lepus a longitudinal enamel ridge closing the opening of the internal enamel-

inflection (rt of my figures), as figured and described by Pere Heude ("fissure qui se ferme avec unc lamellc d'email

chez I'adulte," op. cit. p. 65, pi. siii. fig. 4), and would gladly learn in which species this occurs.

t G. li. Waterhouse, ' A Natural History of the Mammalia,' ii. p. 73 (1S4S).

j Eug. Biichner, ' Wiss. Eesultate der von X. 31. Przcwalski nach Central-Asien unternommenen Keisen,' i. 5.

p. 193 (1894).

SECOND SERIES. — ZOOLOGY, VOL. VII. 05

466 DR. C. I. FOESTTH MAJOR ON

superior incisor " hns the external groove less deep, and placed nearer to the inner edge

of the tooth," than in the Common Hare * ; and W. T. Blanford states of Lopiis dmjamis,

Blf., that "the upper incisors appear very indistinctly grooved " f. The species

mentioned are precisely among those in which the groove of the upper incisors

is very deep ; but they present the appearance of being shallow, owing to the cement

which incompletely fills them. In fact, the cement appears in all species in which

the groove penetrates further backward than in the commonly accessible species

(i. eui'OjJcBUS, Oryctolagus cunioulus), and it is in that case very often associated with

other complications which we have now to consider.

Hodgson gives as one of the distinctive characters of Oaprolayiis hispidus the

following : — " the groove in fi'ont of the upper incisors is continued to their cutting-edge

so as to notch it " |. Strictly speaking, the cutting-edge of the upper leporine incisors is

always notched — even in Lepus europcBus ; only, in C. hisp/'dus (text-fig. VIII), the

groove, filled with cement, is much broader and penetrates further backward, so that

the natural section presented when the incisor is viewed from its lower side (same fig.)

shows the groove under the form of a A^ery elongated triangle, with the apex at its

posterior end. A more complicated form has been noticed by Hilgendorf, as stated in

the following brief sentence: — "Die oberen Schneidezahne von Lepus caUotis aus

Mexico uud Lepus nigricollis aus Indien sind gabelig schmelzfaltig (dentes complicati) ;

die entsj)rechenden ZJihne der afrikanischen Hasen bilden durch eine einfachere

Einbuchtung des Schmelzes einen Uebergang von jenen zu den anderen Hasenarten" §.

In a later note by the same writer fiirther particulars are given ||. In the text-

figures I-XXIV are shown, enlarged (about 4x1), the principal modifications of

the enamel-folding of upper leporine incisors viewed from below and with the anterior

border directed downward. Some slight difi'crences between the few descriptions

given by Hilgendorf and my figures of the supposed same species are apparently

due to different causes : in the first place, because Hilgendorf describes tooth-

sections. Moreover, specimens of the same species may vary slightly {of. figs. XVI &

XVII), owing partly to individual variation. But the shape of the enamel-fold varies

equally at different stages in the age of the animal ; species whose incisors show the

most complicated pattern in the adult have as yet no trace of this in very young

animals ; and, vice versa, in very old specimens complication tends to disapj)ear again.

As shown by several of the text-figures, slight variations between the right and left

incisor of the same individual also occur. These circumstances will, of course, iiave

to be taken into account for systematic purposes.

The most complicated folding in Hilgendorf's inateinal was i)resented by a L. callotis,

Wagn. (=i. mexicanus, Lichtenst.), from Mexico ^, in the shape of a T, whose transverse

* Op. elf. p. 77. — R. Swinhoe (Proc. Zool. Soc. Loud. lcS70, p. 234) makes a similar remark with regard to

L. haiiuinus.

t W. T. Blanford, -'On New Mammals from Sind," P. Z. S. London (lS7-f), p. (563.

J Jouru. As. Soc. Bengal, xvi. 1, p. 576 (1846).

§ Sitzungsber. Berl. Ak. Wiss., Sitzg. 14 Dec. 1865 (1866).

II Sitzungsber. Ges. naturf. Freunde Berlin, Sitzg. 15 Jan. 1884, pp. 18-21. % Op. cit. pp. 18, 19.

FOSSIL AND EECEjN'T LAGOMOKPHA. 467

part, turning backward, rims ajiproximately parallel with the anterior border of the

tooth, and is slightly folded from behind, so that it may be compared with an

outspread fork. Figs. XVI and XVII, re2:)resenting the left incisors of two

specimens from Mexico in the Nat. Hist. Museum, labelled Lepus callotis, show this

same form, with a slight complication of the transverse part in one of them (XVII).

L. melanotis, Mearns (fig. XV), from Clapham, New Mexico, belonging to the same

group {llacrotolagus), exhibits in the right incisor the T pattern in a much reduced

form, and in the left a condition approximating to that of the African L. saxatilis, of

which more hereafter.

The nearest apjjroach to L. callotis is seen, according to Hilgendorf, in L. dayaims,

Blf., to which species he refers also the L. nlgricolUs of the first note. I have figm-ed

(fig. XVIIi) the right incisor of the co-type of L. dayanus, from Sukkur, Sind (Br. Mus.

Z. D. No. 90.4.9.2), which corresponds almost exactly to Hilgendorf's description. A

nearly similar form I find to lie exhibited by L. hainanus, from Hainan (fig. XIX) ; the

folding, however, is considerably shorter, and the opening broader. In L. nigncollis

from Ceylon (fig. XXI) the branches of the fork are more elongate, and the anterior

opening is considerably more constricted, than in L. hainainis.

L. feguensis, Blyth, from Pegu (fig. XX), shows a further complication, already

foreshadowed by one of the callotis specimens (fig. XVII), there being three branches

of the fork. Not much different is the left incisor — the rio-ht one is damaijed — of a

L. nigricoUis from the Nilghiris (fig. XXII), and both incisors of L. ruficaudatus

[L. kurgosa, Gray) from the Punjalj (fig. XXIII). The maximum of complication

known to me is exhibited by a L. ruficaudatus from Rajputana (fig. XXIV), where the

left incisor exhibits a four-branched fork, the right being a slight modification of the

same pattern.

Following the description of the incisors of L. dayanus, Hilgendorf gives that of an

vindetermined skull brouglit home from Africa by the Von der Deckeu Expedition. In

this the T with a narrow opening is still strongly marked, but the median moiety of the

transverse part is reduced. The whole of the enamel-fold occupies less sjoace than

in L. dayanus, not being so much extended either backward or laterally *. This

description applies fairly well to my fig. XIV, L. Victorice, Thos., from Nassa, Victoria

Nyanza, except that the opening of the fold is not narrowed.

Pigs. IX, X, and XII represent L. saxatilis, F. Cuv., from Pirie Bush, Kiag William's

Town (Cape), Transvaal, and " Cape of Good Hope " respectively, in none of which

IS there a bifurcation at the posterior end ; the folding penetrates far backward and

the opening is wide, as described by Hilgendorf f in L. saxatilis. Fig. XI, '^ Le^ius

sp.", from Sena, Zambesi, is of the same pattern ; and so is L. Whytei, Thos., type-

specimen, from Pacombi P^iver, Nyasa (fig. XIII) ; in the latter, however, the fold

penetrates further back than in figs. IX-XII, and the opening is comparatively more

restricted. To this form seems to approach Hilgendorf's specimen of " Lepus cajjcnsis,"

* Op. cit. p. 20. t 0/>. (■('. p. '21.

65*

468

DE, C. I. rOESYTH MAJOE ON

sa

xav

Anterior end of upper Leporine iuoisors, from below. Enlarged.

No,

I.

II.

III.

IV.

V.

VI.

VII.

VIII.

IX.

5.

XI.

XII.

XIII.

XIV.

XV.

XVI.

XVII.

XVIII.

XIX.

XX.

XXI.

XXII.

XXIII.

XXIV.

Lcpus variabilis (altaicm).

L. variabilis, J.

X. $inaiiicus.

L. Judcsd, Gray, J , type.

L. sinensis, Gray, type.

L. cumaniais, Thos., type.

" L. yarkandcnsis ? "

Caprolagus hispidus, Pears.

Lepus saxafilis.

L. samtilis, (^ .

Lepus Bp.

L. sa.ratilis.

L. Whytci, Thos., J , type.

L. Victorite, Tbo3.

L. {Macrotolacjus) mclanoiis, Mearns, ^f .

i. ( „ ) callotis.

L. { „ ) callotis.

Lepus dayanns, co-fype.

L. hainanus.

L. pegiieiisis, Blf., J .

L. nic/ricollis, F. Cuv.

L. nigrivollis.

L, nificaudutus {kiirr/osa. Gray).

L. Tuficav.datus.

Russia.

Altyie, Morayshire.

Midian, N.W. Arabia.

Palestine.

China.

Venezuela,

Koko Nor.

(Ind. Mus. Coll.— i?. H. Hodgson.)

Pirie Bush, King William's Town (Cape).

Transvaal.

Seua, Zambesi.

C. G. Cope.

Pacombi River, Nyasa.

Nassa, Victoria Nyanza.

Chipliani, New Mexico.

Mexico.

Suklcur, Sind.

Hainan

Pegu.

Ceylon.

Kotagiri, Nilghiris.

Punjab.

Bajputana.

Brit. Mus. Z. D. .535 a.

525 a.

1176 a.

49.5.l;!.4.

94.2.15.2.

78.8.9.1.

64.8.17.5.

38.10.29.23.

94.9 25.18.

94.2.2.12.

79.11.21.204.

98.10.8.1.

93.11.26.2.

83.2.6.3.

42.12.6.5.

94.1.25.14.

95.3.7.2.

94.5.9.29.

58.9.22.2.

53.8.29.37.

90.4.9.2.

70.7.18.18.

91.5.12.1.

81.4.29.7.

91.10.7.1.54.

91,10.7.151.

FOSSIL AND RECENT LAGOMOIIPIIA. 469

from Mozambique *, collected by Peters, which, however, is certainly not a Lepm capensis.

The latter differs scarcely from i. enropceifs, Pall., s. 1. (including L. oecidentalis, de

Wint.), by its minute enamel-folding-, not filled with cement.

The forms which remain to be described (figs. I-VII) are all approximately of the

same type, viz. a triangular fold with the apex turned backward ; the fold in none

of them stretching so far back as in Caprolagm hispidus (fig. VIII), mentioned above.

The pattern of the latter is approached somewhat by that of fig! VII, from

a specimen labelled '' Lepus ^arkaiidensis?," from Koko Nor (Br. Mus. Z. D.

No. 94.2.2.12), exhibiting an enamel-fold with thick borders, but shorter than in

C. hispidus, and with a much wider opening. It is decidedly not L. ijarkaiidensis, Giinth.

The type of the latter, which is not figured, approaches in the form of the folding

L. sinensis, Gray, the type of which (Br. Mus. Z. D. No. 38.10. •-'9.23) is represented in

fig. V. Both are imperfectly filled with cement, in L. sinensis still less so than in

L. tjarkandensis. The latter differs also from the former by the opening and the

whole fold being narrower.

L. tihetunHs, Waterh., has no trace of cement ; in the shape of its fold it is

intermediate between the former two ; the opening is slightly broader than in L. yark-

andensis.

The conformation of the type of Gray's '-i. Judicce " (fig. IV), from Palestine, and

of "i. sinuificus" (fig. Ill), from Midian, N.W. Arabia, almost identical in both, is

shown by the figures.

L. timidus, Linn. {L. i-ariahiUs, Pall.) (figs. I & II) hardly differs, Imt still the two

figures of this species show that there are slight differences between a specimen

from Prussia (fig. I) and one from Scotland (fig. II). In this species I have always

found the enamel-fold with a filling of cement, though very often incomplete. In

L. europceus, Pall., I have never met witli a trace of cement. This difference would

seem to be a good character for distinguishing isolated fossil incisors of the two species ;

but it is probable that much-weathered specimens of L. timidus may have lost their

cement.

Lepus cumanicus, Thos., from Venezuela (Br. Mus. Z. D. No. 94.9.25.18), the type of

which is represented in fig. VI, stands somewhat apart l)y its very narrow and

comparatively elongate enamel fold.

Hilgendorf holds these complications of the enamel in the upjier incisors to be a

specialization, the only reason given being that in the fossil Prolagus {3L/ol((gus) nothino-

of the kind is seen. " Phylogenetisch betrachtet, ist die bedeutende Schmolzentwickluno-

des Lepus mexioanus gleichfalls ein Extrcni ; denn die Einbiegung der Schmelzplatte an

der Vorderflache tritt bei den fossileu Leporidea-Gattungen {Myolagus) als eint; seichte

Einknickung auf , deren Seitentheile fast die ganze Vorderflache einnehmen " t. This

argimient would be of some weight if Prolagus could be considered ancestral to

Lepus ; but this is certainly not the case, although the molars of the former are of a

more primitive type than those of the latter. As insisted upon in the jiresent

memoir, the Lagomyida?, of which Frolagns is a member, run parallel with the

* Oj:i. fit. p. 21. t Ojj. cit. p. 20.

470 DK. C. I. rOllSTTH MAJOE ON

Leporidas from the Lower Miocene (or it may be from the Oligocene) to the present

time.

The incisors provided with enamel-folds point back towards cuspidate incisors, for

the enamel-folds of lophodout and laminated teeth are obviously the derivates and

horaologues of the " valleys " separating the cusps or tubercles. Now it is very

suggestive that we meet with cuspidate incisors in Plesiadapis, a genus from the lowest

Eocene of Rheims, classed among the Lemuroidea by Lemoine and other writers,

considered by Schlosser and me to be a very primitive Rodent. In the jaws of

Plesiadapis the teeth are greatly reduced in number. In the lower jaw we have only

one powerful elongated incisor, directed obliquely forward and upward, and separated

from the five cheek-teeth — the premolars being already reduced to two — by a con-

siderable diastema. On its posterior face the lower incisor has a cingulum supporting a

small cusp. The upper incisors, too, are separated by a long interval from the five

cheek-teeth, and appear to have been three in number (Lemoine considers the very small

outer one to be the canine). The two outer pairs are very small and unicuspidate ;

the inner pair robust, generally tricuspidate, there being an anterior pair of cusps, and

backwardly an additional cusp, which starts from a kind of cingulum *.

If we imagine the cusps of these upper incisors of Plesiadapis to have become

lengthened in accordance with a general change of the more brachyodont incisors

into a hypselodont one, and their interstices filled with cement, so that by trituration

a level surface can be produced, the result would be a pattern somewhat similar to

that of several of the figured Leporida^. The posterior cusp of Plesiadapis, projecting

from behind into the cavity f , would produce a posterior ramification like that of the

Leporidse.

The test will lie in the search for Tertiaiw Leporidse exhibiting an intermediate stage

between the condition of the upper incisors of Plesiadapis and that of recent Leporidge.

An examination of the incisors of Paheolagtis might decide the question.

Genus Palji;olagus.

Palceolagus, from the Tertiary of North America, is represented by Leidy | and by

Cope § as showing in the teeth only one character distinctive from the genus Lepus,

viz. the more simple conformation of the anterior inferior premolar of the extinct genus,

and of this character more hereafter. When, however, we go over the descriptions,

accompanied by numerous figures, and an examination of originals, several of which are

in the British Museum, we cannot but be struck at once by some very essential differ-

ences in the triturating surfaces of the two genera. When do we ever meet with

molars in any species of Lepus showing the complete absence of all traces ^of

enamel, with the exception of part of the marginal border % This is the case in old

* Lemoine, in Bull. Soc. Gcol. France, xix. 1, p. 278, pi. x. iig. ."^O, n, /;, t (1891).

t Lemoine, 1. c. pi. x. fig. 50, 6, c.

+ Proc. Acad. Philadelphia, p. 89 (1850) ; id. ' Extinct Mammalia of Dakota and Nebraska," p. 332, pi. xsvi.

figs. 14-20 (1869).

§ ' The Vertebrata of the Tertiary Formations of the West,' i. p. 870, pis. Ixvi., Ixvii. (1883).

FOSSIL AND liECENT LAGOMORPHA. 471

specimens of Falceolagus. TIic pattern of less worn teeth, too, is rather different from

what occurs in Lejius. In none of the numerous triturating surfaces of Fnlcvolagns-

teeth figured do we meet with a transverse fold penetrating so far outward as in the

four intermediate teeth of Lcpus, and in the true molars and posterior premolar of

Lagomys. This is confirmed by Cope's description : — " The inner side of the four inter-

mediate molars is deeply grooved/o;- a short distance " (italics mine; cf. Cope's figures),

" which gives a fissure-like notcli on attrition. This disappears after use, as does also a

less profound crescentic fossa in the middle of the crown, whose concavity is directed

outward " *.

This statement, in my opinion, does not fully describe the pattern in young specimens,

which seems to be very ephemeral in Falcpolagus. In a fragment of the right upper

jaw of P. Kaydeni in the Brit. Mus. (5727), of which I give an enlarged figure

(PI. 36. fig. 36), the alveolus of the second premolar (p. 2) is sliown, and the three

teeth p. 1, m. 1, m. 2 are seen in place. The empty alveolus of the premolar

suggests that in its contour this tooth very much approached the corresponding tooth

0^ Prolagns oeningensls (PL 36. fig. 21), and to judge from \\hat we find in the following

tooth (jj. 1) there is a strong assumption that the pattern of p. 2 of Pcdceolagus also

resembled that of Prolagus cen'mgensis. P. 1 of Palceolagus exhibits the internal notch

{a) with which we are acquainted in TitoHomys and in the deciduous teeth of Prolagus,

Lagomys, and Lepiis, and wliich moreover persists as such ia the premolars of Prolagus,

in the second premolar of Lagomys, and in the anterior premolar of Lepiis. In the

premolar of Palceolagus we find, on proceeding inward, a crescentic central enamel

islet in the centre of the crown, known already from the descriirtions and figures of

Leidy and Cope. It is, too, an old acquaintance of ours ; for to all appearance it is the

homologue of the large internal enamel-fold {h) of Tltaiiomys, whose fiu'ther history we

have followed up in tlie other genera. But this is not all. From the antero-external

corner of p. 1 of Pahvolagits starts an enamel-fold in a postero-internal direction,

terminating near the outer end of tlie crescentic fold's posterior horn. No mention is

made of this outer fold in Leidy's and Cope's descriptions ; it is, however, visible in

one p. 2 of Cope's figures (pi. Ixvii. fig. 16 a) ; but I have not seen it delineated for

the same tooth together with the crescent fold, as in the figure which I publish. The

outer fold just described is undoubtedly tlie homologue of the outer enamel-fold (c)

of Titanomys, and I do not doubt that still younger stages of PaUvolagus — which

have been figured by Cope, but in an uusatisfectory manner — will show a greater

development of both the enamel-folds, and therewith a stronger resemblance to the

pattern of the Titanomi/s-teeth and the posterior premolars of Prolagus.

The true molars of Palceolagvs in the specimen figured exhibit only the crescentic

central islet (6) and the internal notch. As stated by Cope in the passage quoted above,

and as shown likewise by the illustrations of both the American writers, the internal

notch and the crescentic islet are worn away by attrition, without any other change taking

place. In this consists the great difference between the American fossil and all the forms

* Op. cit. p. 876.

472 DE. C. I. POKSYTH MA.JOE ON

previously described in this paper. While in all the upper grinding-teeth of Titanomys

the initial condition, two crescent folds and an internal notch, is retained throughout life,

and this is more or less so in the premolars of ProloQus, in the molars of the latter the

crescentic folds are worn away and the internal notch is enlarged to a transverse fold, s

in the molars and p. 1 of Lagopsis and Lagomys, and in the molars and posterior premolars

of Lepiis s. 1. Milk-teeth and very young permanent molars of Lepus show, with slight

variations, the pattern before described as characteristic of moderately-worn teeth of

Fulceolagns. No modernization takes place in the latter ; the only change we perceive,

by the further progress of wear, is the complete obliteration of the crescentic folds and

of the notch on the inner side. In Lepiis, the large crescentic fold of the deciduous

teeth, and a small islet external to it — present in some of the species, and representing

the external crescentic fold of Lagomyida3 — ^disappear at a very early stage of the two

posterior premolars and of the two anterior true molars, and are replaced in the

permanent teeth by the transverse fold already described.

The permanent teeth of Palceolagus, therefore, can only be compared with the

deciduous teeth of Leinis; like these (PI. 36. fig. 26), they exhaust their primitive

pattern, without evolving a secondary one *.

Pcdceolagus cannot find a place in our phylogenetic series {Titanomys — Frolagus —

Lagopsis — Lagomys). With regard to the condition of their upper cheek-teeth, the

species of Palceolagus in which these teeth are known would follow after Titanomys.

But they are certainly not the forerunners of Frolagits, except in the form of the true

molars ; while Frolagus is more conservative tlian Palceolagtis in the conformation of

its two posterior premolars. On the other hand, Falceolagus is certainly the forerunner

of Lepns, and presumably its ancestor ; and this cannot be said of the LagomyidcB, in all

of which the upper m. 3 has been lost.

To resume. — We have in the preceding pages followed the transformation in the

pattern of the upper check-teeth on three lines : — (1) From genus to genus ; (2) from

behind forward in the dental series ; (3) from young to old.

(1). From genus to genus, we might almost say from species to species, the series is as

follows: — Felycocloidty-pe {Felycodus, Flesiudapis) — Titanomys visenoviensis — 1'. Fontan-

^lesi — Falfeolagus — Frolagus ceningensis — F. sardus — Lagopsis — Lagomys — Lepus.

Felycodus and Flesiadapis are genera of the Lower Eocene.

Titanomys appears in the Lower Miocene, and vanishes in the Middle Miocene.

Frolagus appears in the Middle Miocene and lingers on, protected by an insular habitat,

until the Neolithic period.

Lagopsis is at present kno^Ti only from the Middle Miocene.

Lagomys makes its appearance in the Pleistocene and survives to the present day.

Lepus, preceded by the Oligocene and Miocene Falceolagus, appears with many of its

present generic characters in the Lower Pliocene, and survives to the present day.

* The remarkable Hare from Sumatra, Nesohgus Netsfluri, approaches Pdlaolagiis more than other recent

LeporicUe, inasmuch as, by the feeble development of the transverse enamel-fold (PI. 37. fig. 17), it represents a first

stage in the evolution of the secondary pattern. The same form exhibits other primitive features, to be described

later on.

FOSSIL A^"D EECEXT LAGO^rOKPHA. 473

(2) From behind foncnrd in flic dental series. — Tlie true molars are the first to lie

transformed, and successively one after the other of the premolars, the anterior pre-

molar (p. 3) being the most conservative.

(3) From young to old. — Tlie cheek-teeth of the genera under consideration exhiltit, in

the first developed jiarts of their shaft, more or less evident traces of the ancestral

pattern; mostl)/ so the deciduous teeth, which are cast olT Avlien the primitive pattern

has almost vanished, and without sliowing a beginning of transformation ; least so

the true molars, \Ahich in the first stages observable of the calcified tooth, and before

trituration has set in, show the primitive pattern already reduced and the secoudaiy in

process of evolution.

Lower Molars of Lagomorpiious Rodextia.

To state it in a general way, the lower molars of the Lagomorpha present the

same characters as their upper antagonists : viz. anteriorly in the series we meet with

complication, posteriorly with a simple transverse j)attern. On closer examination,

however, it may be seen that in the mandibular teeth the process wliich we have followed

through its various stages ia the upper set is accelerated. Although it must be taken

into account that we have one premolar less below than above, none the less — leaving for

the present out of consideration the reduction which takes place at the posterior end

(m. 3) — there is in the adult mandible only one tooth, the anterior, which diffei's materially

from the others, by being more complicated. In Titanomys, the oldest member of the

groitp, this tooth (p. 2) as generally described and figured, presents a more simple

structure tlian in later genera, and even than do the other teeth of Titanomys, by being

composed of only one column, divided into two lolies by an inner and an oiiter enamel-

inflection ; whereas in the teeth situated posteriorly there are two columns, the division

between them being complete ; tliey are held together by cement.

"We meet here with a phenomenon which is pretty general among Eodents, whether

the number of their cheek-teeth be three, four, five, or six. To state it more fully : —

1. The mandibular cheek-teeth precede those of the maxilla in the reduction of their

number; mc have instances of .', of '' and of .. cheek-teeth, but never of "!, or ;, or j.

2. Very frequently the anterior tooth in the lower series, whether it be p. 2, or p. 1,

or m. 1, is more complicated than those behind; which circumstance suggests that the

complication has some connection with the anterior position of the tooth in question.

3. When the anterior lower tooth is nearly or actually equal in pattern to those behind,

this is generally so in older forms. Thus we find that in Winge's Anomaluridae —

including mostly Tertiary genera — provided with four lower teeth, the anterior one (p. 1)

is equal or subequal in size and pattern with the others, and sometimes even of smaller

size. Again, in Muridte, with three inferior cheek-teeth, the geologically older forms

have the anterior one (m. 1) equal or subequal in size with the two following, whereas

the complication of the first molar appears only in more recent forms. The same is

true with regard to the lagomorphous Rodentia, where the anterior tooth is p. 2, and

in the oldest known genera {Titanomys, Fala;olagiis) of a rather simple pattern,

second SKRIES. — ZOOLOGY, VOL. VII. 66

474 DE- C. I. rOESTTH MAJOE ON

The explanation whicli I suggest for these curious occurrences is as follows : — When an

anterior tooth drops out from the mandihle — generally through an apparent interference

of the incisor with its pulp — some compensation for its loss is necessary, as the corre-

sponding maxillary tooth is generally still in its place ; this compensation is brought

about by a complication on the anterior side of the tooth which has become the first in

the series by the loss of the origiually anterior one. Those genera which are nearer in

date to the epoch when the anterior tooth was lost will still present a less complicated

form of that which has succeeded to this position, while in the later genera the

foremost tooth will have acquired the complication. When p. 2 is dropped, p. 1 will

become the foremost tooth, and the same cycle will recommence, and so on.

I next proceed to a closer examination of the lower cheek-teeth, starting from those

of Titanomys. A superficial comparison of the anterior tooth, jTli, of this genus, Avith

that of the other Lagomyida;, shows that in the former it is more simple than in

the latter, and presents an approximately tetragonal outline at its triturating svu-face ;

in FrolcKjus, Lagopsis, and Lagomys this is triangular (apex in front). Thus it

is that we find the tooth generally described ; but on closer, examination the matter is

somewhat more complex. I have figured five specimens of p. 2 of Titanomys Fontannesl,

from La Grive-Saint-Alban, in different stages of wear ; four are isolated teeth

(PL 37. figs. 1-4) ; the fifth is in its place in a left ramus, presenting the complete series

of two premolars and three molars (PL 37. fig. 7). Of T. visenoviensis I have one speci-

men, in a fragment of the right ramus, containing the two premolars (PL 37. fig. 25).

This species is from the AUier (Bravard Collection, Br. Mus. Geol. Dep. No. 31095).

The first stage in T. Fontannesi (fig. 1) represents a tooth which has not yet come into

wear. In the main it is composed of two lobes ; the anterior is subconical, the posterior

is much more extended transversely, and composed of a tapering outer and a thicker,

rounded inner cusp ; moreover, on the middle of its posterior surface appears a small

cusp {t) ; the anterior surface of this lobe is wrinkled. Even in this early stage the

separation of the two lobes is incomplete ; a ridge, running almost longitudinally back-

ward, from the middle of the posterior side of the anterior lobe towards the posterior,

shows that trituration Avould very soon have connected the two by a narrow isthmus of

dentine, thus separating from each other an outer and an inner enamel-inflection. This

we sec, in fact, brought about in the second stage (fig. 2). Towards the middle of the

anterior margin of the anterior lobe, a feeble cusp is visible in the first stage (1, fig. 1) ;

the same is more distinct in the second stage (1, fig. 2), where it is nearer to the inner

side. This cusp, to all appearance, is Wiuge's 1, Osborn's paraconid. Whether it

contains potentially some other element I must leave undecided ; as a mtitter of fact,

in the two teeth described, it does not occupy exactly the same position ; and in

T. visenoviensis (1, fig. 25) it is more approximated to the outer side. What is called

the paraconid is, however, somewhat inconstant in its position*. In p. 2 of T. vise-

" Sue c.i/., the text-figuros in "W. D. Matthew, " A Revision of the Puerco Fauna," Bull. Am. Mus. Nat. Hist,

is. {l^'Jl).

FOSSIL AND EECENT LAGOMOEPHA. 475

noviensis (fig. 25) it is evident as a small vertical pillar, h'ing far below the triturating

surface of tlie moderately worn tooth.

To return to the second stage in Titcowmys Foiitannesi. The inner of the two

principal enamel-inflections resembles somewhat in outline its homologue in Lagopsls

verus (PI. 37. fig. 26, p. 2). It is seen to be composed of two parts : a posterior, which

communicates by a narrowed opening with the internal margin of the tooth, and thence

runs straight towards the middle of the tooth, and an anterior circular one; the

two communicating with each other by a narrow channel. The terminal cusp [t] is

situated much nearer the inner side than in the first stage. I have dealt with this

terminal cusp of the lagomorphous Eodentia on a former occasion, and homologized

it with Osborn's hypoconulid * ; a view from which I see no reason to depart. In

the third stage (fig. 3) this hypoconulid is still apparent ; but the " paraconid " has dis-

appeared, and so has the circular part of tlie inner enamel-inflection. The transverse

posterior part of the latter is on its way to be shut off' from the inner margin, and to

assume the form of a circular enamel islet. " t " is visible on the posterior internal edge

of the tooth. In the fourth stage (p. 2 of fig. 7), the circular enamel islet is quite

separated from the inner margin, and lias become confluent with the outer enamel-

inflection, so that the triturating surface of the tooth presents — if we except a small

enamel fold limiting anteriorly the still extant t — only one enamel-inflection, pene-

trating from the middle of the outer margin and approaching the inner. In the fifth

stage (fig. 4) we find only the latter inflection, t also having disappeared. This tooth in

its general outline again approaches the first stage.

No lower deciduous teeth of Titanomys are at my disposal. Filhol has figured d,

and A.-, of T. visenoviensis from Saint-Gerand-le-Puy (AUier) ; from this figure nothing

more can be made out than that in d. 2 the anterior part seems to be more produced

anteriorly than in p. 2. No description is given of the triturating surface f.

The anterior lower premolar of T. visenoviensis is distinguished from the same tooth in

T. Foi/faiinesi by the persistence of the enamel-inflection of the inner side in the adult

(PI. 37. fig. 25) ; in the immature specimen figured by Gervais, and originally described as

a separate species, T. frilob/is, the two enamel-folds are confluent in the middle of the

triturating surface, thus comj^letely separating an anterior and a posterior lobe J. The

terminal cusp (t) present in the specimen figured (PI. 37. fig. 25) must certainly be

expected to be visible likewise in younger specimens ; Gervais makes no mention of it in

this tooth ; in the profile view oi the tooth, however i^, there are two vertical grooves on

the inner side. A small anterior pillar ("paraconid") on the anterior side (1), lielow

the triturating surface, lias already been mentioned as present in the British Museum

specimen. -'■

■* Proc. Zool. Soe. Lnnaon, i8!t3, p. 203. .'.''■

t H. Filhol, " Etudes des Mammif. t'oss. de Saint-Gerand-le-Puy, AlHer," Ann. Sc. Geo), x. p. 29, pi. iii. fig. 3

(1879).

+ Zool. et Pal. Fr. p. .51 : " les denx lobes de la prcmiire [molaire] ny sent point encore reunis I'un a I'aurre par

\m petit isthme d'ivoire " ; pl. 46, fig. 1 (1S.59).

§ O^j. cit. pl. 46, fig. 1 c.

66*

476 UR- C. I. FOKSYTil MAJOR ON

We have to follow up this same tooth, ]3r2, ia the other genera of Lagomyidae. In

Lagopsis verus (PI. 37. tig- -6), from the Middle Miocene of La Grive-Saint-Alban, the

posterior transverse lobe of p. 2 is undivided, with uo trace of t. The next anterior lobe

is separated from the former by a T-shaped enamel-intlection on the inner side — which

has already been mentioned as approaching in form its homologue in Titanomys

Fontcmnesi (tig. 2) — and by an outer one. We have, therefore, here the tAVO enarael-

infiections of T. visenoviensis and of the yoimg of T. Fontmmesi. However, in Lagopsis

the lobe is more distinctly divided than even in fig. 2 (T. Fontannesi), into an outer

and an inner cusp ; for in the former the T-shaped inflection extends more anteriorly,

aad the lobe is delimited in front by two smaller enamel-folds. These latter

delimit on their anterior side two further cusps, an outer and an inner ; the latter

corresponds to 1 (paraconid), as seen by comparison with tig. 2 ; the former may

correspond to the pillar ■which in T. visenovienms (fig. 25) is nearer the outer than the

i:mer side. In any case, in Lagopsis the anterior part of p. 2 is much more developed

than in 'I'ltanumys; for Ave have, in the former, two comparatively stout cusps against

one feeble cusp in each of the two species of the latter. Besides, there is in Lagopsis a

small odd cuspidule, situated in front of the anterior pair, and in the middle line of the

tooth, to which it gives a triangular form.

The principal difference in Lagomys, to Avhicli Lagopsis is nearly related, consists in

the fact that the characteristic T-shajjed inflection of the Lagopsis p. 2 is either

absent or replaced by a slight indentation of enamel. The latter is the case, e.g., in

Lagomys rutilus *, the former in L. alpinus and L. nepuleiisis f. Moreover, the odd

anterior cuspidule has vanished in Lagomys.

In Prolagus also tlie anterior part of d. 2 is much more complicated than in j^ of

Titanomys. Eig. 5, PI. 37, shows this tooth of Frolagtis sardtis, var. cursiiaims, from the

ossiferous breccia of Toga, near Bastia (Br. Mus. Geol. Dep. No. M318(5) ; tig. 6, the

same tooth of the IVLiocene Frolagiis ccningeasis from La Grive-Saint-Alban ; both from

the left side. I liaA'e still younger stages than those figured of tliis deciduous molar,

showing the posterior lobe completely separated from the middle one. The anterior

lobe of d. 2 of P. ceningensis (fig. 6) is tripartite, as in Lagopsis, but the odd anterior

cuspidule is less distinctly divided from the inner than in the latter genus. In

tlie tooth of F. a'liingensis the whole tripartite lobe is connected only by cement

with the rest of tlie tooth ; in younger stages it is still more divided into a smaller

external cusp — which is isolated, also, in the d. 2 of F. sardiis figured (fig. 5) — and a

lari;er internal one comprising both the "' paraconid," 1, and the odd anterior cuspidule.

The isolated small external cusp of F. sarcitis is situated lar below the triturating

surface ; the iimer larger one, showing no sepanited odd cuspidule, is connected on its

inner side with the rest of the tooth, as happens likewise, though very rarely, in the

corresponding permanent tooth, p. 2, of the same genus. In still more advanced stages

* For a fi^nu-L'il specimen of this tooth see E. Schiifl", " Ueber Linjonujs rui'dus, f^evertzoft'," i^ep.-Abdr. aus Zool.

Jiihrl.i. ii. \>. 09, tig. 5 h.

t H. Hcustl, " Beitiiige z. Keuiitii. I'ossiler Saiigethiere," Zcitschr. dcutsch. geol. Ges. viii. pi. xxvi. figs. 2 & (i

(1856).

FOSSIL AND EECENT LAGOMORPIIA. 477

of wear of the deciduous tooth of Frolagus, the whole of the anterior tripartite lobe

appears invariably connected with the posterior part of the tooth by a dentinal isthmus,

thus giving the whole tooth some resemblance to m. 1 inf. of a vole ; and it has, in

fact, been mistaken for a molar of Mtcrotus.

A characteristic feature of the anterior lower premolar, '^7^, of Prolafjus, is an odd

isolated cusp or pillar, connected only by cement with the rest of the tooth, and

situated on its anterior side, thus giving to the whole tooth a triangular outline, as in

Lagopsis. In Prolagns aniingensis (PI. 37. fig. 9) this cusp is situated near or close

to the middle line ; in P. sanlns *, of which I have examined hundreds of specimens,

its position is nearer the inner side. As before mentioned, in very rare cases of

P. sardiis, this usually isolated cusjj is united with the tooth near the inner side, as in

d. 2 of fig. 5. In other cases of P. oenuigenals (fig. 12, PI. 37-) and P. sardus, it may

be united with the tooth near its outer side. This latter fusion I found to have

taken j^lace in 10 specimens of ytTH out of 575 examined, from the ossiferous breccia

of Monte San Giovanui (Sardinia) (P. sardus), and in two cases out of 84 examined

from Toga, near Bastia (P. sardus, var. corsicanus). The cusp was united with the

tooth near the iuuer side in two of tlie 575 examples from Monte San Giovanni.

Cusp " ^" I have met with only in p. 2 of Frolagus ehaiiiis (page 460).

A comparison witli the specimens before described shows the usually odd isolated cusp

to be the homologue of the " paracouid " combined with the anterior odd cuspidule of

Lagopsis, while the outer cusp of the tripartite anterior lobe is jiresent, also, in p. 2 ; in

P. ceniiigrnsis it is generally stouter than tlie outer cusp (6) of the median lobe, whereas

in P. sardus the inverse is the rule. In exceptional cases of P. sardus 1 find this outer

cusp of the anterior lobe completely isolated, as it is in the deciduous tooth of fig. 5.

A second characteristic feature of the pTs of Prolagus (figs. 9, 12) is a longitudinal

enamel-fold, filled with cement, which, beginning from behind the isolated anterior

cusp, proceeds backward to near the hinder margin of the tooth, thus completely dividino-

the middle lobe into an outer and an inner cusp, and incompletely so the posterior one,

on which it also encroaches. The longitudinal arrangement of the elements of this jj. 2

of Prolagus. in opposition to the transverse arrangement of the posterior teeth, is very

striking.

I now proceed to a consideration of the same tooth in the Leporidse. With reference to

p. 2 of Palceolagus, Leidy states: — "The anterior four inferior molars [of Paheolayus^ bejr

a near resemblance in Ibrm and constitution Avith the corresponding series of TUauonigs

visenoviensis, as represented in j)!. 46 of Gervais' Zool. et Pal. Fv." f. Comparing it with

the same tooth in Lepus, Leidy further says in the original description of Paheo-

lagus : — " The first inferior molar is bilobed, and not trilobed as in the latter (Lepus) " j.

In his second memoir the first inferior molar of Pakeolagus is said to be composed of a

double column as in the others, the same tooth in the Hare of a triple column §. Cope

* R. Hensel, l. c. pi. xvi. fig. S.

t ' Extinct Mammalian Fauna of Dacota and Xebraska,' p. 333, pi. xxvi. (iSii'j).

t Proc. Ac. Philad. p. 89 (18.56).

§ Extinct ilamm. Fauna, &c., p. 331.

478 DE. C. I. rOESTTH MAJOR ON

supplements this description by the following information based upon a great number of

remains : — " 1 am able to show that it is only in the immature state of the first molar

that it exhibits a double column, and that in the fully adult animal it consists of a

single column with a groove on its external face " *. A more complete description is

given on p. 878 : — " There is the merest trace of a posterior lobe " — corresponding to the

termiual lobe (/) of Tltanomys — "at tliis time, and that speedily disappears. The

anterior lobe is subconical, and is entirely surrounded with enamel. By attrition, the

two lobes are speedily joined by an isthmus, and for a time the tooth presents an

8-shaped section, which was supposed to be characteristic of the genus. Further

protrusion brings to the surface the bottom of the groove of the inner side of the shaft,

so that its section remains in adult age something like a B." From this description it

appears that p. 2 of Falceolagus Maydeni is almost exactly like the same tooth in

Titanoniys Fontannesi.

The difference between the p. 2 of Talffolagus and Lepus is stated by Cope to be as

follows : — In the extinct genus the first tooth " consists of one column more or less

divided. In Lopus this tooth consists of two columns, the anterior of which is grooved

again on the external side in the known species." Leidy's description of the Leporine

p. 2, as being composed of three lobes or columns, is more accurate. It is quite true

that in the adult p72 of many Leporidaj appears to be composed of two columns, witli

an additional antero-external enamel-inflection (see Pi. 37. figs. 13 & 19) ; but by no

means universally so, and, so far as my experience goes, it is neA'er so in the young

(PI. 37. figs. 8, 18, 22, 23).

In the immature p7^ of Lcinis s. 1. (PI. 37- figs. 8, 22), as well as in the immature stage

of all the other inferior molars of the same, the posterior and the middle-lobe column are

completely divided ; only in later stages a very ]iarrow isthmus of dentine connects them

on the inner side (PL 37- figs. 33, 20, 23). The fact of a primary separation into two

lobes of the inferior molars of Lepxis was first announced by Hilgendorf +.

The unworn lower p. 2 of the "Wild Piablnt (PI. 37- fig- 8) displays anteriorly the

anterior of the three columns completely divided into a smaller outer and a larger inner

subconical cusp ; this division is brought about by a longitudinal enamel-inflection,

which invades part of the middle lobe as well, so that the latter is also divided, though

incompletely, into an outer and an inner cusp. (Compare the homologous enamel-

inflection of Prolacpis, fig. 9.)

Passing on to the lower cheek-teeth backAvard from p. 2, the various stages which I

have represented in PI. 37 show in the lower molars the simple transverse pattern of the

two lobes of p. 1 ; m. 2 is a secondary one, as in Ihe ujiper teeth, though in the inferior

molars the original pattern is much more ephemeral, least so in p. 1, which forms a

transition between p. 2 and the true molars.

* ' The Yertebrata of the Tertiary Formations of the West,' p. 874, pis. ')(! & 57 (1883). t Op. cit. p. 870.

X " Bcstebeu die unteren Backziihiie anfaiigs aus z-nei getrennteii Schmclzlamellcii, 'welche erst spiiter mit

ciuaiicler verwachsen, so class cin wcsciitlicher TTiitcrschicd z-\vischen zusammengesctzten mid schmclzfaltip;eii Zahnen

dcr hasenartigcn Thiere nicbt zu machen ist ."' Monatsher. d. K. preiiss. Akad. d. Wiss. zu Berlin. Sitzg. v. 14.

Dee. 1SG5, p. G73 (1800).

FOSSIL AND EECENT LAGOMOEPHA, 479

These teeth, as a whole, exliibit in younger stages a greater longitudinal diameter than

in the adult ; this is notably the case in Titanomijs (PL 37. figs. 7, 10, 24), and is chiefly

due to the greater develojiment and indepeudence of the terminal cusp {t).

The youngest mandible of Titanomijs which I possess is a left ramiis of T. Fonfannesi

(Br. Mus. Geol. Dep. M5267 h), figured PI. 37- fig. 10. P. 2 and m. 3 have dropped

out. Flanking the three corners of the alveolus for p. 2 are visible the small

alveoli for the roots of deciduous teeth ; the anterior and the postero-external seem to

belong to d. 2 ; the postero-internal was presumably occupied by the anterior root of

d. 1. P. 1 is still in the socket and had not yet come into use. Both the principal

lobes composing this tooth are surrounded by enamel ; but the wrinkled central surfaces

of the lobes are composed of dentine, with the exception, perhaps, of the summits of some

of the wrinkles, which, to judge from their shining appearance, mav bear a very slight

coating of enamel *. In p. 1 and the true molars of adiiU Tltanomys Fontannesi, the

enamel bordering appears interrupted in the middle of the anterior margin (PI. 39.

fig. 6 a). Hilgendorf has recorded a similar instance of the absence of the enamel

bordering on the inner half of the anterior border in the lower cheek-teeth, p. 2

excepted, of Lejy/isf. The anterior transverse lobe of p. 1 (fig. 10) still shows

traces of having been divided originally into an outer and an inner cusp and of the

" paraconid " on its anterior border ; vestiges of the latter are visible also on p. 1 of a

slightly older individual (fig. 16, of the right side), and on m. 2 of the same right ramus.

The terminal cusp f (" hypoconulid ") is present in both p. 1 and m. 1 of the younger

sj)eciraen (fig. 10), as wxdl as in p. 1, m. 1, and m. 2 of the second individual (fig. 16),

and in p. 1 of a third (fig. 21, right side). In the left ramus, exhibiting the complete

series of five cheek-teeth (fig. 7), i is present in all of them. In p. 1 of T. visenoviensis

(fig. 25) it is remarkably large, although partly fused with the posterior lobe ; and it

is equally present on the posterior border of m. 1 and m. 2 of the second specimen of

T. visenociensis (fig. 24) ; so that, contrary to what has been stated by former Avriters, the

cuspidule in question may be present in all the four anterior cheek-teeth of this sijecies.

Passing on to the recent representatives of the family, it may be seen from fio-. 22

(Pl. 37-), of an immature Caprolaijuti ///.•ijjichts, that p. 1 nearly apjH'oaches p. 2 in its

anterior complication. The two principal lobes are not yet connected on the inner side

by a dentinal isthmus, but are merely held together by cement ; the anterior lobe is

distinctly composed of an outer and an inner cusp, the latter being more pointed and

slightly higher than the former. The anterior border of the tooth presents two minor

cusps, an outer and an inner, the median odd cusp of p. 2 being absent. Both the lobes

show a very marked wrinkling of their surface. As in p. 2, t is apparent on the

posterior margin of the second lobe.

Two very distinct minor cusps are likewise visible on the anterior border of ]). 1 of the

* We have here an instaucc similar to that recorded by Heusel ia JIus decumaiius, 7-attus, museuhts, si/Juaticus

agrarius, and minutus, where in perfectly unworn molars " iiberzieht der Schmelz die Ilociier der Zahnkrone nieraals

vollstiindig, sondern liisst an den Spitzen das Zahnbein frei hervortreten." Zeitschr. d. deutsoh. geol. Ges. viii

pp. 283, 2S4, pl. siii. figs. 2, 3 (1S56).)

t Sitzungsber. Ges. naturf. Freunde zu Berlin, 1-i Jan. ISS-t, p. 23.

480 DR. C. I. FOESTTH MAJOR ON

Rabbit (fig. 8) ; the first lobe of the same is mainly composed of an outer and an inner

cusp, separated by a median hollow ; the second lobe is wrinkled as in p. 2 of tlie same

species. The minor cusps, though less distinct, are visible also in m. 1 and m. 2 of the

Eabbit, in m. 2 almost vanishing. I have noted tlieir presence in the true molars of

young specimens of other species as well {Lcpns europam, Lepns sp. from China,

Syloilagus brasiliensis) : t is generally present in unworn deciduoiis teeth, in premolars,

and in molars of several Leporidse.

To sum up tlie above as regards the lower cheek-teeth, p. 2 — m. 2. An original

ari'angeinent into outer and inner cusps, sej^arated by a median longitudinal valley, is

traceable in the lower molars of Lagomorpha generally. It is more distinct in the

anterior cheek-teeth, and persists throughout life in p. 2 of most genera in both families ;

it is less distinct, though perfectly perceptible, in true molars, in which it very soon

disappears by wear, being replaced by the transverse arrangement. In p. 2 we have to

distinguish between an older complication and secondary additions ; the increase in the

plication alone is present in the posterior cheek-teeth, the anterior cusp not. On

comparing adult stages of p. 2 of Titanomijs witli the corresponding tooth of all other

Lagomorpha which, on the Avhole, are more recent forms, the latter appear to be more

complicated ; but in young stages p. 2 of Tiianomys Fontannesi presents also a com-

plicated appearance. This cannot be an incipient complication, for that joart of the

shaft of the tooth which is situated on the opposite end of the pulp-cavity is, as a matter

of coiu'se, always the oldest. llilgendorf has found the interruption of the enamel

border on tlie inner side also of lower molars of Lepiis *, a fact which points towards

a degeneration of this part of the tooth, and would seem to coll for a compensatory

increase on its outer side. However, I am ]:ot aware of a jjerceptible additional increase

on the outer side of lower molars of more recent forms, as compared with older ones f.

Upj)er molars are more progressive than lo\^■e^ as concerning occasional additions.

An ingenious explanation of this general occurrence is given by Winge in the following

remark: — ' The explanation of the maxillary teeth making a larger increase than those

of the lower jaw is in all likelihood the following : they are placed in an unmovable

bone, where the conditions for nourishment are more favourable than in the compara-

tively slender and movable mandible " %. In our special case an increase of the lower

molars in the transverse direction can be the more dispensed with, since in the Leporidae

the movement of the jaws is chiefly lateral. This will not be denied by any one who has

ever examined the shape of their glenoid cavity or watched a Eabbit or Hare chewing.

Moreover, the dentine of both upper and lower cheek-teeth shows unmistakable signs of

this movement, in the piesence of ti-ansverse stria?, due to the action of the transverse

enamel crest of the opposite tooth.

It remains to discuss in some detail the last molar, m. \'>, ahoiit which verv diver2:ent

views ha,ve l)een put forward.

* Op. at. p. 23.

t Neither am I aware of lacun.T on the internal enamel hoideriiic; of any Lngomvida^ ; but I must add that no

sections were made.

I Vidcnsk. Meddelelser naturliist. Forciiing i Kjiihcuhavn f. Aar. ISSl?. p. ]7 (181^=3).

FOSSIL AND EECENT LAGOMOEPHA.

481

Fig. 7, PI. 37, shows this tooth iu place in a left mandibiilar ramus of Tltmiomys

Fontanuesi. It is not a simple cylinder, as in Lagopsis and Lacjomijs, but is composed of

two lobes, a larger anterior one and a small posterior, attached to the former in the

same manner as in the anterior molars the terminal cusp {t) is attached to the lobe

preceding it, viz. separated from it by cement, only iu the upper part. Eor this

reason, and because the anterior lobe of m. 3 shows traces of greater complication,

1 homologize the posterior lobe of this tooth with t of the anterior molars ; the anterior

lobe of m. 3 would then represent hoth the principal lobes of the anterior molars.

When discussing the tooth-formuhi of Tltanomijs, allusion was made to Filhol's

suggestion that the terminal cusp of m. 2 of T. visenoviensis might be the representative

of m. 3 of the recent Lagomys, in the specimens of the former where this is missing.

" Si cette opinion est juste, on pourrait en tirer comme conclusion qu'a im certain

moment, sur les animaux voisins des Lagomys, il y a une tendance a la simplification du

systeme dentaire, d'abord par la fusion de la derniere dent avec ravant-derniere, et

ensuite par la tendance a la disparition de cet element sonde " *. Filhol here ignores

the circumstance that all the anterior teeth have this "troisieme lobe " as well, wbile in

their case we have not at our disposal an occasional small isolated tooth to suggest a

fusion theory. Besides, as was said before, this theory may be at once disposed of by a

glance at our fig. 7, showing m. 2 with a well-developed terminal cusp {t), m. 3, the

supposed homologue of this latter, being liliewise present. Other figures also (figs. 10,

16) show m. 2 with the terminal cusp, together with the alveolus of m. 3.

As will be seen further on, Schlosser seems to incline to the opinion that the presence

of a terminal cusp in m. 2 of T. viseiiooiensis is an indication of mTs having become fused

to m. 2 ; for he says that m. 3 of Lagopsis verus may be the analogue of the terminal

cusp (f) in m. 2 of Tltanomys f. It is, however, difficult to make out what meaning

he wishes to attach to this vague term " Aualogon ".

Lagopsis. — The type-specimen, Hensel's Lagomys venis X,\\ii^ ^xa lower cheek-teeth,

the last being a small cylindriform tooth, precisely as in the recent Lagomys, to which

Lagopsis is closely related. The tooth in question was not complete in Hensel's

specimen, but a fragment seems to have remained inside the alveolus ; else he would

have presumably used the term " ausgefallen," whereas he says, sj)eaking of the condition

of this tooth, that it is broken away (" weggebrochen ").

Three more or less complete mandibular rami, from Deggenhausen, Elgg, and Hohen-

lioven respectively, are mentioned by 11. v. Meyer, and drawings of their teeth, found

among H. v. Meyer's MSS. have been reproduced by Schlosser §. They show an

agi'eementin their pT^ with HanseVs Lagomys verus, and Schlosser therefore concludes ||,

rightly, I think, that they are of the same species. He further deems it not improbable Tf

that Lagomys wningeiisis, H. v. Mey., from ffiningen may be identical with Lagomys

* Ann. Sc. Geol. x. p. 28 (1S79).

t ' Nager des europ. Tertiiirs," p. 32 (1<S84).

X Zeitschr. d. deutsch. geol. Ges. 1856, p. 688, pi. svi.

figs. 12, 13.

§ Op. cit. p. 31, pi. viii. figs. 40, 46, 49.

]| Op. cit. pp. 31, 32.

IF Op. cit. p. 32.

SECOND SERIES. — ZOOLOGY, VOL. VII.

67

482 DR. C. 1. FOKSYTH MAJOR ON

verm, Hens." That this is true with regard to the CEningen specimen in the British

Museum has been sliown on p. 402. I can affirm the same for the Seyfried specimen *

at present in the Constance Gymnasium, where I examined it and found it to have

the characteristic ^2 of Lagopsis veriis. With regard to the Carlsruhe specimen t,

since the shape of its pT^ cannot be clearly made out from H. v. Meyer's figures

and description, the true position of this "i. ceningensis, H. v. Mey.," cannot be

satisfactorily determined for the present. It might quite as Avell be a Titanomys

Fontannesi. In the former, as well as in the specimens from Deggeuhausen, Elgg, and

Hohenhoven, no last molar (m. 3) could be seen ; as, however, this tooth is very caducous,

its absence in the fossils is not in the least conclusive ; it may have dropped out and the

alveolus been filled with matrix. Nor does Schlosser attacli any great weight to the

absence of this small tooth in the three specimens drawn in H. v. Meyer's MSS. ;

this, however, for reasons with which I completely disagree. " Auf das Fehlen des

letzten einfachen Backzahnes l)ei den drei von H. v. Meyer gezeichneten Exemplaren

darf wohl niclit allzuviel Gewicht gelegt werden. Es ist uicht unmoglich, dass auch hier,

wie bei Titanomys vise)wviens/s,im.novma\en Iviefer nur 3 zweilobige Molaren vorhanden

sind, und dass daher der stiftformige m. 4 " (meaning m. 3) " des Hensel'schen Originales

als Analogon des bei T. msenomensis abnorm vorkommenden Lobus des m. 3 " (meaning

m. 2) " betrachet werden muss." %

This whole statement is somewhat vague ; the author seems to assume (1) that in

T. viseiioviensis both the m. 3 and the third lobe {t in my figures) of m. 2 occur only

abnormally; (2) that in " Zagomys veriis" the presence of m. 3 is equally an abnormal

occurrence. From these two assumptions the inference is drawn that mTs in the type

of Lagomys vents is the analogue of the equally abnormal third lobe in m. 2 of

T. viseiioviensis. Schlosser concludes by saying that he is almost inclined to consider

the presence of m. 3 as a juvenile character, and that this tooth is caducous (hinfallig).

This is very probal^ly true with regard to T. rlsenoviensis, and I liave myself suggested

it in the preceding pages. But it is decidedly erroneous witli regard to mTs of Lag apsis

verus, as are all the other suggestions tentatively put forward in the passage quoted.

With regard to T. viseiioviensis, the matter has been fully discussed above. As to the

mTs of Lagopsis verus, in all my specimens from La Grive-Saint-Alban, either the tooth

itself or its very distinct alveolus is present (PI. 37. figs. 14, 26). Deperet, too, has before

figured a mandibular ramus of Lagopsis verus from the same locality, showing the m. 3 § ;

and Biedermann has described this same tooth in specimens from Elgg.

Prolagus. — There is no third inferior true molar, m73, in this genus ; m. 2 is composed

of three lobes, the posterior connected with the middle one by cement, in the same

way as the latter is with the anterior one. From this circumstance Pomel concluded —

ust as Filhol has in the case of Titanomys — that in 'Prolagus m. 3 had become fused

with m. 2. Of the Prolagus ceningensis of Sansan, he says : — " Ceux de Sansan different

* H. Y. Meyer, " Fossile Siiugetliiere, etc., vou Giuingen,'' Fauna d. Yorwelt, p. 6, pi. iii. fig. 1 (184.5).

t Ih. pi. ii. fig. 1.

t Oj). cit. p. 32.

§ Arch. Mu8. Lyon, iv. p. 104, jjl. xiii. figs. 10, 10 ct (1887).

FOSSIL AND KECENT LAGOMOKPHA. 483

encore, comme sous-^enre, par la derniere molaire inferieure, qui a trois prismes par

reunion de la cinquicme molaire a la quatrieme " *. Eraas holds the same opinion f.

This theory would at first sight seem to be supported by what Dei)erct has found

in the ProIagKS of Roussillon. He figures two mandibular rami '^, in one § of

which he records five cheek-teeth, in the other 1| only four ; and he goes on to say : —

" Cette dilFeronce est moins importante qu'elle ne pent sembler au premier abord ;

elle tient simplement a ce que le dernier prisme d'email de la serie dentaire est soude

au prisme jirecedent de la quatrieme molaire dans I'une de ces mandibules, tandis que

ce meme prisme libre constitue une cinquieme molaire dans la fig. 29. Cette soudure,

qui se fait d'ailleiirs uniquement par I'intermediaire d'une certaine quantite de cement,

ne me parait pas avoir I'importance qu'on lui a attribuee pour la distinction des deux

genres Lacjomys et Frolagus, puisqu'elle est variable suivaut les sujets dans le petit

Leporide de E,oussillon " ^.

I agree witli Prof. Deperet that this difference has no great importance in the E-oussillon

jaws, though not for the reasons adduced, for I apprehend he is mistaken when he

institutes comparisons with Lacjomys, and considers that the isolated prism of his

fig. 29 " constitue une cinquieme molaire." H. v. Meyer met with similar occm--

rences among twenty mandibular rami of Frolagus oenmgensis (Kon.) from Steinheim,

and refers to them in the following words : — " In some instances one might be induced

to believe that the posterior of the three prisms constituting the last molar is separated,

so that the creature would have the character of Lagomys " ; but he judiciously

adds : — " On closer examination, however, it can be seen that tlie posterior prism is

included in the alveolus of the rest of the tooth, so that it evidently is part of the

latter " (" dass das hinterste Prisma nicht durch die Alveole von dem iibrigeu Zahu

abgeschlossen ist, zu dem es daher offenbar noch gehort) " **. Numerous mandibular

rami of the Frolagus ceii'mgensis from La Grive have passed through my hands, as well

as from 600 to 700 of F. sardus from the Corsican and Sardinian ossiferous breccias and

caves. Not unfrequently I foimd the third prism of m. 2 separated from the rest of

the tooth ; but by the criterion established by H. v. Meyer there could never be a doubt

as to the interpretation, which invariably was that, either by fracture or by the weathered

condition of the cement, the last prism had been separated from m. 2 ; as are likewise,

though more rarely, separated from each other the two prisms of the aiaterior teeth.

I do not doubt for a moment that the same explanation will hold good in the case of

the E-oussillon specimens. In Frolagus each of the prisms has its alveolar niche

formed by two partial septa starting from the outer and inner alveolar border ; but these

must not be confused witli the complete septum separating one alveolus from the

other.

I consider the tliird prism of ni72 of Frolagus to be the homologue of t of the

* Cat. meth. et desor. Vert. toss, du Bassiu de la Loire et de I'Allier, p. 43 (1853).

t Wiirttemb. naturw. Jahresh. xxvi. p. 170 (1870).

% " Aiiim. plioo. du Koussillon," Mem. Soc. Geol. France, i. p. 57, pi. iv. (1890).

§ Op. tit. pi. iv. figs. 2iJ, 29 a.

II Oj}. cit. pi. iv. figs. 28, 28 a. f Oi>. dt. p. 57. ** Neiies Jahrb. 1865. p. 8t3.

67*

484. 13R- C. I. rOKSTTlI MAJOR ON

Titanomys-ieeih ; and that itiTs having been lost in tlie former genus by some means or

otber, the terminal cusp of m. 2 has become enlarged in compensation. "We have

numerous analogies for similar occuri-ences, but we have none for the ever-recurring

theories of fusion between tooth and tooth, which on closer examination always break

down. This notwithstanding, we shall still hear of them, since they yield the explanation

which lies nearest at hand.

Again, although Prolagus presents in its molars, at least in the upper ones, more

primitive characters than Zagopsis and Lagomys, it cannot be considered to be the

direct ancestor of these ; for it cannot be surmised that a tooth— mTs — after having

been lost, reappears in a later genus. Hilgendorf regards m. 3 of Lepus as a recent

acquisition, for he terms it '' phylogenetisch der jiingste (Zahn) " * ; presumably for

the same reason for which he considers tlic maximum of enamel-plication observed by

him in upper incisors (of ^' Lepus mexicanus") to l)e "phylogenetisch ein Extrem " t,

because there is no trace of it " bei den fossilen Leporiden-Gattungen {Mi/olagus)."

There is no good reason for considering the Miocene Prolagus {Ili/olagus) in the

ancestral line of Lepus, simply because no true Leporida? have been found in the

European Miocene ; nor in inferring from the various primitive characters of P;'oZ«(7?<s

that the absence of m. 3 is a primitive character as well. Besides, Hilgendorf does not

take into consideration the fact that Lagop)sis and Titanomys, both of which are contem-

poraneous with and even partly {T. visenoviensis) older than Pfolagus, possess a m. 3.

I presume that, for similar reasons, Hilgendorf would consider the m- 3 of Le^ms a recent

acquisition also ; and here we must remember tliat the Oligocene Pala'olagus has

both m. 3 and m. 3.

Noack describes the last lower molar of young Lepus saxaUlis as composed of two

antero-posteriorly placed cusps, which seem (" scheinbar ") to be separate, but at any rate

(" jedenfalls ") are only loosely connected, which makes it doiibtf ul whether they ever

coalesce to form a compact tooth. This conformation of m. 3 is in the author's opinion a

sufficient justification for the folloAving generalization: "Jedenfalls ist im Unterkiefer

von L. saxatilis noch die Tendenz zu 6 Backenzahnen vorhaudcn." | Why not, while we

are at it, towards eight ? — since it is stated immediately afterwards that the same

partitioning of the two lobes is also visible in two of the anterior molars. The

* Sitzungsber. d. Ges. natiirf. Freundo Berlin, Sitzung v. 1.5. Januar 1884, ]>. 23.

t Op. cit. p. 20.

+ Th. Noack, " Neue Beitriige zur Kenntniss d. Siiugethier-Fauna von Ostat'rika," Zool. Jahrb. Abth. f.

Syst. etc. vii. p. 54.5 (1693). The writer of this pamphlet has examined numerous dentitions of fostal and young

Habbits, and " -i. vulgaris" (meaning L. eiiropaits), and finds among other things in their cheek-teeth cusjjs which

are absent in the adult. So far, good. Apart from this, his descriptions and generalizations show on almost

every line that he has approached this difficult subject without sufficient scientific training. Hilgendorf's short

sentence of 1865 : " Die oberen Backzahne junger Hasen sind mit einer halbmondfurmigen Schmelzrijhre verschen,

wodurch ein Ubcrgang zu dem fossilen Mi/olat/us gebildet wird,"' — is of infinitely higher scientific value than the

•la^es filled with laborious descriptions in the paper quoted. If the author had taken Hilgendorf's words as a

starting-point and a guide in the investigation of upper leporine cheek-teeth, he might have been able to

do some useful work. He knows about tritubercular teeth ; he also seems to be aware that on ojie occasion

the molars of lagomorphous Rodents have been compared with those of diprotodont Marsupials, and that

FOSSIL AND KECENT LAGOMOEPHA. 486

numerous juvenile dentitions wliicli were at the author's disposal might have shown him

that the separation of the two lobes is characteristic of young stages in the inferior

cheek-teeth of Lepns generally.

The Bony Palate in the LAgomorphine Skull.

The greatly reduced hony palate is considered to be one of the characteristic features

in the skull of Lagomorpha. At first sight the only difference in this respect between

Leporidae and Lagomyid* appears to be that in the latter family the palatal bridge is

shorter than in Leporidte. On investigating the matter more closely, however, it may

be seen that in Leporidte the bony palate is shortest in the genus Lepus s. str., viz. in

those forms which are most sj)ecialized for running and leaping ; and that the

shortness is principally due to a reduction in length of the os palatinum. In Lagomyidse,

on the contrary (PI. 39. figs. 34, 36, "jj"), the latter bone is comparatively elongate,

while the part of the bony palate formed by the maxiliaries (m) is greatly reduced, so

that in some cases the latter do not even join in the laiddle line antei'iorly, the middle of

the anterior margin of the palatal bridge being formed by the palatine bones. As seen

from the figiu'cs, Prolagus (fig. 36) is in this respect scarcely different from Lagomys

(fig. 34).

It might, a priori, be expected that this speci?lization of the Lagomorpha will be

reduced to a minimum, in other words that the bony palate will be longest, in the oldest

members of the group, and this is in fact so. Cojie describes this part of the skull

of Palceolagus as follows : — " The palatine bones are flat and occupy more than half the

palate between the molars. Their common suture is at least as long as that of the

maxillaries, and extends as far forward as the posterior border of the second molar. Prom

this point the anterior suture extends to the posterior border of the third molar. The

palatal notch is rectangalar, and is not wider than the palatine bone on each side of it." *

some phylogunetic speculation has been based thereon. The author avails himself of these two types, the

tritubercular and the diprotodont, in tracing two primitive types in the teeth of one species, Lepus sa.catilis ; the

anterior upper cheek-tooth is referred to the tritubercular type ; the conformation of the two anterior lower teeth,

on the other hand, " decidedly suggests the molars of Kangaroos and Wombats, and makes it probable that the

ancestors of the Lagomorpha were llarsupials, holding ahout the middle between Phascohjnii/s and Lagorchestes"

(p. 545). By the cheek-teeth of its ripe embryo, the Wild Rahbit is far removed from Lepus curop<ms (p. 553) ; and

the cheek-teeth of the latter were evolved from the tritubercular type (p. 551). The rabbit's skull approaches the

Marsupial type (p. 551). The author seems to be unaware of the existence of deciduous cheek-teeth in the Leporidae.

On p. 549, the anterior of the upper cheek-teeth is twice termed p. 1. Supposing that we have really to do with

a premolar, the anterior premolar in the upper series would be p. 3, according to Hensel's mode of writing, adopted

by the present writer, or p. 2, according to the usual custom, hut under no circumstances p. 1. Considering,

however, that the two teeth referred to by Prof. Xoack belong, the one to a mature, the other to an unripe embryo

of L, europa'us, in which species the tooth-change takes place only some time after birth, the alleged p. 1 is in

reality a d. 3 (d. 2 of authors). On pp. 544 and 545 the remarkable circumstance is noted that in the half-grown

L. saxatilh the second and third anterior upper cheek-teeth are more retarded in their development than the same

teeth in embryos of L. europceus. The very oljvious explanation is that those of the former sjiecies are premolars,

those of the latter deciduous teeth.

* E. D. Cope, 'The Vertebrata of the Tertiary Formations of the West," i. p. 875 (lS7(i) pi. Ixvi. figs. 1, 4

0883).

486 DR. C. I, FORSYTH MAJOR ON

Tlie only known palate of Titanomys is that figured by Pilliol *, which too is elongate.

According to him t, the length of the palatal bridge in Lacjomys and Titanomys

respectively is as follows : —

millim.

Lagomys tibetanus ()'002.

Lagomijs oyoloita 0"0015.

Titanoimjs rismovieiisis. . . 0'0045.

The suture between the palatines and maxillaries is not shown in the iigure of

Titanomys. Thanks to the kindness of Mons. M. Boule, I have been able to examine the

original in the Paris Museum, and can state that in this oldest member of the Lagomyidse

the family character is already very evident in the reduction of the maxillaries,

inasmuch as the palatines occupy the anterior margin of the bridge in the middle line, the

two maxillaries not joining each other. The difference in the length of the palatal bridge

between Titanomys on the one side, and Lagomys (with Prolagns) on the other, is tlierefore

wholly due to the greater elongation of the former's palatine. lu Falceolagus 1 both

bones are lengthened, as compared with other Leporidae, and especially with the most

modernized species of tlie family . The anterior palatal notch formed by the maxillaries

extends forward slightly beyond the anterior margin of p. 3, as it does in Nesolagus

Netscheri (PI. 39. fig. 38), which is one of the most primitive of recent Leporidse. The

posterior palatal notch of Pala;olagus reaches as far backward as a line uniting the

middle of the alveoli of m. 1. Besides, the horizontal portion of the ossa palatiua is also

transversally much less reduced than in most of the recent Leporidaj, the breadth of the

posterior palatal notch being approximately equal to half the breadth of the space

between it and the alveoli. While in this latter character JPalceolagus convei'ges

towards the Lagomyidse, or rather goes beyond them — for, to judge from the figiires, the

palatal notch of Palceolagus is considerably narrower tlian even in Titanomys — it is

thoroughly leporine with regard to the part which the maxillaries take in the formation

of the bony palate.

Those among recent Leporidse which, on account of their several primitive characters,

may be placed in a separate section (Caj)rolagus-group), as oj)posed to Lepus s. str., are

more primitive also in the character of the greater autero-posterior length of the palatal

plates of the palatine and maxillary bones, as may be judged from various instances

figured in PI. 39. Pig. 32 represents the palate of Cajjrolagusjiisjjidus (Pears.) ; fig. 33, of

Sylvilagiis {Romerolagus) Nclsoni; fig. 37, the same part of Oryctolagus crassicaudatus

(Geoffr.) i fig. 38 that, already mentioned, of Nesolagus Netscheri of Sumatra. It is well

known that the bony palate of the Rabbit, of which a figiu'e is not given here §, has a

greater longitudinal extension than ia the Common Hare and that its palatal notch

is narrower ; both these characters are much more pronounced in the young. Pig. 35

* H. Filhol, " Etude des Mammiferes fossiles de Saint-Gerand-le-Puy (AUier)," Ann. Sc. Gcol. x, pi. 3, lig. 13

(1879). t 0^>. cii. p. 31.

+ Cope, ap. cit. pi. Ixvi. figs. 1, 4.

§ lixoeUent lower views of skuUs of the Rabbit, side by side with those of Lepus ewopceus, have been figured by

H. V. Nathusius (' Uber die sogenannteu Leporiden," pi. ii. 187G).

FOSSIL AND EECENT LAGOMOEPHA. 487

{PL 39) represents these parts of a young SylvUagiis braslliensis (Linn.), wliich closely

resembles Faheolagus in the great antero-posterior extension of both the palatine and

the maxillary bones and in the very narrow palatal notch, both coming near to the

normal condition of Mammals.

As might have been expected, the Pliocene Lepus valdarmnsis, Weith., also presents a

more normal palatal region than the various specialized species of Lepus, and may for

this reason alone be assigned to the Caprolagus section. The anterior and posterior

palatal notches are much narrower than in L. europcvus, and the whole of the bony

palatal In-idge is considerably longer ; this being especially due to the elongation of the

maxillaries *.

The greater rednction of the palatal plate of the maxillary bone in Lagomyidfe,

as compared with Leporidge, might seem to be due to the greater backward prolongation

of the foramina iucisiva in the first-named family. On closer examination, however,

it becomes evident that in reality we have to do with a fusion of two originally separated

vacuities, viz. the true foramina incisiva, and a sort of palatal fontanelle behind them.

In Lagomys, the premaxillse generally, though not in all the species, join in the middle

line between the foramina incisiva and the fontanelle behind them ; in Leporidte, the

confluence of the two fissnres has generally, but not always, become complete. An

approach to Lagomyidse (fig. -30) is given by the bottle-shaped appearance of the

"foramina incisiva" which Bangs considers to be characteristic of ''Lepus sylraticus

transitionaUs "f — the same occurs also in other American Leporidfe — ^and which is but

the remnant of the original separation of the true foramina incisiva from the palatal

fontanelle. I therefore do not think that Winge is right, when he assumes that the

separation of the two openings is a secondary character in Lagomys, brought about

by the new formation of a bony plate $. Judging from Cope's figure §, the fusion of

botb openings seems to have already taken place in PalcBolagus. But if we judge from

recent forms, in which tlie premaxillai are very thin in this region, it ajipears probable

that the apparent fusion in the figured palate of Palceolagus is due to the defective

preservation of the premaxillas in the figured specimen.

On the Limb-Skeleton of Lagomorpha.

There is a great diff"erence between the Lagomyidte and Leporidfe, and between the

various members of the latter, in the absolute length of the fore and hind limbs, and in

theii- relative length, compared with each other. The diff'erences, moreover, are not only

in size ; and it is the antebrachium which in the first place presents notable divergences

in the different groups. Even for systematic purposes it will be necessary henceforth to

take into consideration these, as well as other, parts of the skeleton ; and we cannot

content om-selves with such general statements as " hind limbs longer than the fore

limbs," and " hind Umljs and fore limbs subequal."

* A. Weithofer, in Jahrb. k.-k. geol. Keichsaustalt, Bd. xxxix. p. 80 (1880).

t Proc. Bost. Soc. Nat. Hist. ssvi. p. 407 (189.5).

X H. AVinge, ' Jordfundne og milevende Gnavere,' &c., J. c. p. 113 : " Forskjelleii fra Haren er kuo, at det ogeulige

F. incisivum er afskilt ved en nyopstaaet, ikke altid fukUtii'ndig Benbro."' § O^j. cit. pi. Isvi. fi"-. 1.

488 DR. C. I. rOKSTTH MAJOE OX

In comparing the characters of the common Hare (i. europcens) with those of the

domesticated Rahhit, Nathusius enters into full particulars of the differences presented

by the antehvachium, summing them up in the following statements : —

Hare. Rabbit.

Ulna weaker than the radius, situated Uhia stronger than the radius, situated

behind the latter. laterally.

In relation to the basilar length of the skull and the length of the vertebral column,

the anterior and posterior limbs are in their totality, as well as in their different parts,

longer in the Hare, shorter in the Rabbit.

Hare. Rabbit.

Humerus longer than antebrachium. Humerus and antebrachium suhcqual in length.

Length of the antebrachium as compared with the tibia : —

Hare. Rabbit.

Antebrachium shorter than the tibia by Antebrachium shorter than the tibia by one-

about one-fourth its length. half its length*.

With regard to the remarkable differences in the antebrachium of tlie two animals,

the writer concludes that they are doubtless associated with their different habits,

the Rabbit burrowing and the Hare living above-ground f . Put in this general way,

the conclusion is undoubtedly true. Nathusius, however, does not seem to have been

aware that the difference is chielly due to the specialization of the Hares fore-leg, which

specialization is nothing else than the beginning of the process carried much fuiiher in

the modern swift-footed Ungulates. It therefore remains to be seen how far, if at

all, the structure of the Rabbit's antebrachium is a consequence of its burrowing

propensities, — an adaptation to them. Eor neither from what we know of its habits, nor

from the structiu'e of its fore-limb, can the Rabbit be considered to be a truly fossorial

Mammal, as is, e. g., the Mole, or, among Rodcntia, the genera Geomys, Spalax, and

Siphneus.

In districts where the Rabbit finds burrowing in the ground too hard a task, it

manages to do withou.t it J ; as it sometimes does, perhaps, for other unknown reasons.

* H. V. Nathusius, ' Ubur die sogenauuten Lejjorick'U,' pp. 17, .31-33, 67, figs. 2-5 (p. 32) 1876.

t Oj). i:it. p. 33.

X W. Thompson states (Proc. Zool. See. Londoii, part v. p. 52, 1837) that in the North of Ireland persons who

take Rabbits make a distinction between the Burrow -Eahhit and the Bush-Jiahlit, and that the latter is so designated

in consequence of haviug a " form like the Hare, and which is generally placed in bushes or underwood." The

liev. G. T. Dawson, speaking of the Wild Rabbit, says :■ — " There is a variety . . . which never burrows in the ground,

but lies beneath bushes, or among the herbage ot hedges or woods, and is called by the common peoi)le of that part

of Hertfordshire which borders upon Redfordshire the B%(sh-ltahhit, and in the northern parts of the same county

the Stuh-Eahhit .... A non-burrowing Rabbit may, in its distress, scramble into a hole, or burrow, if there happens to

1)0 one in its waj', in which to die in secrecy ; but, as far as my own observation extends, I never remember one

FOSSIL AND EECENT LAGOMORPHA.

489

One of my principal reasons for separating a certain number of LeporidiB, under the

designation of Caprolagns, from the swift-footed Lepus (figs. XXV-XXVIII), is the

I

xxv

SSVI sxw

rigs. XXV-XXVIII. Left antebrachium of Lfpus timldm, Linn. (L. iwlahilis, Pall), ^ reduced. XXV, front view

XXVI, ulnar (external) view ; XXVII, radial view ; XXVIII, posterior view.

Figs. XXIX-XXXI. Len ioreAimh oi S>ih<{la</us hrnsiUensis (Lum.), uat. size. XXIX, front view. I-V = first

to fifth metacarpals, f = carpale 5 (vesalianum) ; XXX, radial view ; XXXI, uluar view.

structure of the antebrachiuni ; but of several of the former it is expressly stated

that they do not burrow at all, or at least that they are not habitual burrowers. I

have thought it would be instructive for my present purpose to record the observed facts

of the physiology of the organs of locomotion of various Lagomorpha, by collecting as

much information as is available to me.

of the bush-mhhifs running to ground, even when wounded, and certainly it is contrary to its habits to do so under

dift'ereut circumstances " (' Zoologist," iii. p. 903, 1845). In W. Thompson's ' Natural History of Ireland' (vol. iv.

p. 80, 1856), his former statement is repeated, and strengthened on the authority of Dr. R. Ball, " who has

long been aware of the difference of habit and appearance between burrow- and bush-rabbits in the County of Cork."'

In Bell's ' History of British Quadrupeds ' (2nd ed. pp. 344, 345, 1874) it is reported that " on moors, where the soil

is wet, Kabbits often refrain from burrowing, and content themselves with runs and galleries formed in the long

and matted heather and herbage. In more than one instance we have known a family to take possession of

a hollow tree and ascend its inclined and decayed trunk for some distance." In comment on this, Prof. Howes has

drawn my attention to the fact that the Oriental Black-necked Hare (L. nigricolJis) habitually resorts to the hollows

in trees when pursued, and that while the European Rabbit may bring forth its young above-ground (' Zoologist,'

ser. 3, vol. i. p. 18) the Hare may do so in a burrow.

SECOND SERIES. — ZOOLOGY, VOL. VII. 68

490

DE. C. I. rOESYTH MAJOE ON

Of Oryctolagus crassicandatus, wlaich, in the conformation of its antebracbium

(text-figs. XXXII-XXXV), is almost identical witb O. cuniciilm (PI. 38. fig. 30), Smith

says in a general way that it inhabits " rocky situations" in South Africa, and that " its

manners connect it closely with the Rabbit." * Alexander Whyte describes the same

species in his journey through the high-lying country in the North Xyasa district, and he

xyxTT

XL

Figs. XXXII-XXXV. Oryctola(jus crasskauduius ((u-oft'r.). — Left fore-limb, iiat. size. XXXII, posterior view ;

XXXIII, front view ; XXXIV, ulnar view ; XXXV, radial view.

Figs. XXXVI-XL. Caprola[/us Jiis^idus {Fears.). — Left fore-liml), nat. size. XXXVI, posterior view ; XXXVII,

front view: »-=radiale, i = intermedium (lunar), ^« = ulnare. l-3=carpalia 1-3.

Cj = carpale 4 (hamatum). XXXVIII, ulnar view : p=pi8iform ; XXXIX, radial view :

XL, front view of antebracbium, proximal end.

too compares it with the Rabbit f. But Dowhere have I found it expressly stated that

this species is burrowing ; the rocky " situations " and " places " to which, according to

both observers, it is confined, certainly would not favour IjurroM'ing propensities.

* A. Smith, in S. Afr. Quart. Journ. vol. ii. p. 87 (1833) (sub " Le/ms rupesti-is").

t " Perhaps the most interesting mammal we secured was the haro of the plateau, and which might well be

termed a ' rock-rabbit.' ... It is very local and peculiar in its habits, confining itself to the highest and most

rooky places on the plateau. On this account wo found it most difficult to procure good specimens. It kept

dodging about the granite boulders, and we seldom got a shot until it was quite close on to us. ... It was never

found out in the open " (British Central Africa Gazette, 15th Oct. 1895 to 1st Feb. 189G, p. 22.)

FOSSIL AND EECENT LAGOMOEPHA. 491

Of the " Lepus hrasUicnsis " of Pciraguay, wliose fore-limbs (text-figs. XXIX-XXXI)

mucli i-esemljle those of tlie Rabbit, D'Azara states expressly that it is not a burrowing

animal*, and the same is confirmed by Rengger f.

About the habits of Sylcilagiis stjlvaticus, the " Grey Rabbit " of the United States, we

know from Bachman that " though it digs no burrows in a state of nature, yet when

confined it is capable of digging to the depth of a foot or more under a wall in order to

effect its escape " |. S. artemisUe, closely related to S. sylvaticm, is described by Clark

as burroAving §.

Special recognition is due to the following graphic description l^y Coues of the

locomotion of three different groups of Hares, viz. the Marsh-Hare {S. palustris), the

"Wood-Rabbit" (S. sylvaticas), and the "Jackass Hares" [L. callotis). Comparing

in the first place the two former, he says : — " The Marsh- Rabbit . . . looks smaller, although

actual measurement does not show any very decided difference in size. This deceptive

appearance is owing to the different gait . . . The animal's gait ... is a direct conse-

quence of the comparative shortness of its legs — of the hinder ones particularly . . . The

animal's general configuration is more squat and bunchy ; it seems to run with its body

nearer the groimd ]|, scuttles along with shorter, quicker steps, more constrained and

spasmodic, moving by jerks, as it were ; and has little or nothing of the free bouncing

movements that mark the progress of the Wood-Rabbit. In these respects the last-

named species is exactly intermediate between the Marsh-Rabbit and the large

" Jackass " Hares {Lepus caJlofis) of the West, in which length of stride, height of

bound, and general freedom of swinging gait reach an extreme. These Western Hares

are the swiftest of their tribe in this country, and the Marsh-Rabbit is just the opposite

As attested by all observers, the speed of the latter is appreciably less than that of even

* " II ne fouille point de terriers, quoiqu'on dise, qu'etant poursuivi, il se cache sous des fcroncs pourris et entre

les debris des vegetaux." (' Essais siir THist. nat. des Quadrupedes de la Province du Paraguay,' ii. p. .58,

1801).

t J. E. Piengger, ' Naturgeschichte der Silugethiere von Paraguay,' 1830. — "Hiihlen oder unterirdische Gange

grabt es keine " (p. 248). " Sein erster Lauf i.st scliuell ; er halt aber uicht lauge aus und wird bald von den

Hunden eiugeholt" (p. 2.5u).

X .Tourn. Acad. Nat. Sei. Philad. vol. vii. p. 3:3.5 (18.37). The following statement as to the feeble endurance

in running of 6'. sylvaticas is almost identical with what Eengger says of <V. hrasiUensis : — " Although it

runs with considerable swiftness for a short distance, yet it soon becomes wearied, and an active dog would

overtake it, did it not reti'eat into some hole of the earth, into heaps of logs or stones, or into a tree with a hole

near its roots. ... In the Isorthern States, where the burrows of the Maryland marmot and skunk are numerous,

this hare retreats to their holes " (op. cit. p. 328).

§ " Wherever the thorny clumps of chapparal and the loose sandy soil afford protection to this smallest of rabbits,

it may be found in great numbers. No matter when or whore one of these maj' be seen, a clump of chapparal or

its burrow seem always at hand ; thus it does not travel far, and a few jumps bring it to a place of safety. . . .

The burrows usually run into sand hillocks formed around bushes : sometimes, however, they are dug into the bare

compact surface." (J. H. Clark, in Spencer F. Baird, ' Mammals of N. America. — Part ii. Special Ileport upon the

Mammals of the Mexican Boundary,' p. 48, 1850.)

11 Cy. also Bachman on Siilrilat/tis j'tilt'-'^ii'is: "Instead of leaping like the common Hare, it runs low to the ground,

darting through the marsh in the manner of the Hat." (J. Bachman, " Descr. of a new Species of Hare found in

South Carolina," Journ. Acad. Nat. Sci. Philad. vii. p. 190. Head May 10th, 1830.)

68*

492 DE. C. I. FOESTTH MAJOR ON

the Wood-Rabbit, though it certainly appears to get over the ground quite cleverly,

particularly to one who has just missed, by under-shooting, a running shot" *.

The most remarkable member of the family, as to its habits, is the " Romerolagus

Nelsoni, Merr.," from Mount Popocatepetl, Mexico, of which it is stated: — "This

singular animal has exceedingly short hind legs, and instead of moving by a series of

leaps, like ordinary rabbits, runs along on all fours, and lives in ruuAvays in the grass

like the meadow-mice " f. Mr. E. W. Nelson, the discoverer of tiiis creature, has

furnished the following further particulars : — " A search under the overhanging masses

of long grass-blades show^ed a perfect network of large arvicola-like runways tunneling

through the bases of the tussocks, and passing from one to another under the shelter of

the outcurving naasses of leaves. It was evident that the rabbits ^vere very numerous

here ... So far as observed, these animals are strictly limited to the heavy growth of

saccatan grass, between about 3050 and 3G50 meters . . . They make their forms within the

matted bases of the huge grass tussocks, by tunneling passage-ways along the surface of

the ground through the mass of old grass leaves and stems, and then hollowing out snug

retreats within the weather-proof shelter thus obtained " %.

■ I am unfortunately unacquainted with the limb-skeleton of this interesting animal.

Although from the foregoing description it results that it cannot be considered a

burrowing animal, I venture to anticipate that its ulna will be found at least as little

reduced as in the common Eabbit, and not placed behind the i^adius.

Hodgson \ gives the following information on the habits of Caprolagus hispidttn

(Pears.) : — " The Hispid Hare is a habitual burrower, like the llabbit; but, unlike that

species, it is not gregarious, and affects deep cover, the pair dwelling together, but apart

from their fellows, in subterranean abodes of their own excavation . . . Less liighly

endowed with the senses of seeing and hearing than the Common Hare or P^abbit, and

gifted with speed far inferior to that of the former or even of the latter species, the

Hispid Hare is dependent for safety upon the double concealment afforded by the heavy

undergrowth of the forest || and by its ow^i burrow, and accordingly it never quits the

former shelter, and seldom wanders far from the latter, whilst the harsh hair of its coat

affords it an appropriate and unique protection against continual necessary contact with

the huge and serrated grasses, reeds, and slirubs in the midst of which it dwells, and

* Elliott Coues, " Observations ou the Marsh-Hare,'" Proc. Boston Sot-, of Natural History, xiii. pp. 87, 88, 80

(18G9).

t C. Hart Merriam, "■ Eouerolafjus Nelsoni, anew Genus and Species of llabbit from Mount Popoeatejietl, Mexico,''

Proc. Biol. Soo. 'V\"ushington, x. p. Kj!) (1896).

X Op. cit. pp. 109, 170.

§ B. H. Hodgson, ■• On the Hispid Hare of the Saul Forest," J. A. S. Bengal, xvi. 1, pp. 573, 574 (1547).

II By later writers it is denied that C. hispidu^ is an inhabitant of the forest. Blanford (' Fauna of British India,'

Mammalia, ii. p. 454, 1891) says : — " According to Hodgson the Hispid Hare inhabits the Sal forest, whilst Jerdon

states with more probability that it is found in the Terai (that is, of course, the marshy tract usually thus called),

frequenting long grass and bamboos &c." Jerdon's words are : — " It frequents jungly places, long grass, and bamboos,

and, from its retiied habits, is very difficult to observe and obtain "' (T. C. Jerdon, 'Mammals of India,' p. 220,

1867).

FOSSIL AND EECENT LAGOMOEPHA. 493

dwells so securely that it is seldom or never seen even by the natives, save for a short

period after the great annual clearance of the Tarai hy fire ; and they tell me that it feeds

chiefly on roots and the bark of trees, a circumstance as remarkably in harmony with

the extraordinary rodent power of its structure as are its small eyes and ears, weighty

body, and short strong legs, with what has been just stated relative to the rest of its

habits. The whole forms a beautiful instance of adajitation without the slightest change

of organism " *. Even if it had not been expressly stated, I would have concluded

from the structure of the fore limbs (lext-flgs. XXXVI-XL) that the Hispid Hare is a

l)ui-rowing animal : in fact, the only member of the family whose organization betrays

fossorial propensities.

Nothing is known aboiit the habits of the Sumatra Hare, Caprolagns {Nesolagus)

Netscheri t. Prom the structure of its fore limbs, PI. 38. fig. 28, it may be safely inferred

that it is a bad runner, and it may be an occasional burrower; but it is certainly much

less fossorial than C. hispidns.

The mode of locomotion of L(Kjoiirys [L. piis/lliis) is thus described by Pallas : —

" Incedunt L. p/isilH elumbi et sul)sultante gressu, sed propter bi-evitatem pedum,

maxime posticorum, neque celeriter eurrunt, nee nisi inepte exsiliunt. In posticos pedes

raro eriguntur " I Winge concludes from this that " the mode of locomotion is therefore

the same as in Lepus.'" Besides, he thinks it probable that the ancestors of Lagomys

have been better runners than the recent species ; this, on account of the resemblance of

the rump- and limb-skeleton between Layomys and Lepiis. Also, according to the same

Avriter, some features in the skull of Lagomys, showing that the organs of smell and sight

are less developed, point nevertheless towards a former different condition §. As seen

from the figures (PL 38. fig. 20), Lagomys resembles ordinary Rodents and Insectivores

in the lateral position and non-reduction of the ulna, and also in its comparatively short

hind legs. This is the primitive condition. Are we, then, to assume that the ancestors

of Lagomys, starting from this condition, reduced their ulna and shortened their hind

legs, only to revert again to the former primitive condition presented by the living

species? Equally far-fetched seems to me the supposition that the choanai had formerly

been wider and the eyes larger. Neither Prolagus (PI. 39, fig. 36) nor Tifanomys supports

the former assumj)tion, and there is no indication of larger orbits in Frolagus, nor of

supraorbital processes in either of the two fossil genera. The statement, " incedunt

L. pusilli elumbi et subsultante gressu," which recalls Coues's description of *S'. palustris

(" scuttles along with shorter, quicker steps, more constrained and spasmodic, moving by

jerks, as it were"), proves, in my opinion, an incipient stage of the leporine locomotion.

* The view expressed ia the latter part of the last sentence is not correct.

t H. Schlegel, " On an anomalous Species of Hare discovered in the Isle of .Sumatra : Lejjus Sctucluri *' (■ Xoti.'s

from the Leyden Museum,' vol. ii. note sii. p. 59, 1880).

+ ' Novae Species Quadrup. e Ulirium Ordine,' p. 35 (1778).

§ H. 'Winge, ' Jordfundiie og nulevende Giiavere (Rodentia),' p. 113.

4,94 DR. c. I. FOEsrrH major on

PiFTH Carpal Ray.

The Pisiform.

Krause descrilies the pisiform of the domestic E-abbit as aiiiculating with the ulnare

on its A^ohir side * ; in the description of the ulna t, it is stated that the distal

termination of tbis bone has a condyle for tlie facet of the ulnare. These two

statements imply that the pisiform of the domestic Rabbit articulates — as in Man —

with the ulnare only. If tliey are correct, the German domestic Rabbits are

different from those of this country ; for in the English domestic and wild Rabbits

I find the bone called pisiform articulating with the ulna as well as with the ulnare ;

this is the case moreover in all Leporidte (PL 38. fig. 2, text-figures XXXI, XXXIV,

XXXVIII), in all Lagomyidte (PI. 38. fig. 4), and in the great majority of Mammalia.

In the Leporidse the pisiform, the proximal part of which extends considerably iu

a transverse direction on the volar side of the carpus, shows even two facets for the

volar side of tlie ulna.

Prom the following statements it appears tliat the so-called pisiform of Mammalia is a

compound bone.

Daubenton mentions three accessory bones in the carpus of Hylohatcs and Iiiuus

ecaudatus ; one of them is, in Sijlobates, situated as follows : " il se trouve place sur

le joint qui est entre le troisieme et le quatrieme os du premier rang ; " situated, therefore,

on the articulation between the ulnare and pisiforme %. The carpal bones of Itiuus are

said to have the same position as in Ilylohates, only differing in their form §. In Papio

the accessory bone in question is said to be wanting ||.

Cuvier's description is almost identical. Speaking of the " ossified nodules in the

muscle tendons " of the carjius, he says : — ■" II y en a deux par exemple, dans le

gibbon et le magot : I'un dans Je tendon du cubital externe, sur le joint du pisiforme avec

le cuneiforme .... manque dans les Sitpajous " ^.

Leboucq describes and figures ** a case in the Gibbon : — " Chez un Gibbon {Hylobates

leuciscns) de la collection de I'Universite de Gand, il existe entre le cubitus et le cul)ital

du carpe un nodule osseux articule lateralement avec le pisiforme [p'. fig. 28). Ce nodule

me semble representer le cartilage qui disparait chez I'homme." (Reference is here

made to the previous description of a cartilaginous nodule which is constantly met with

in liuman enil)ryos of the third and fourth month.) " En meme temps que le crochet

terminal du cubitus s'accuse netteuient, il se develojipe dans le menisque embryonnaire

un nodule cartilagineux elliptique, faisant suite d'une part a la pointe du crochet et de

I'autre se dirigeant vers I'extremite proximale de Tintermediaire." It disappears

* W. Krause, ' Die Anatomie des Kaninchens iu topogr. und operativer Riicksicbt,' 2te Auflage, p. 120 (1884).

t L. c. p. 119.

+ Buftbn et Daubenton, Hist. nat. geu. et partio. siv. p. 10.5 (1706).

§ L. :■. p. 127. li L. c. p. 151.

IT Lerons d'Anat. Comp. 2' ed. i. p. 42-5 (18.3.5).

** H. Leboucq, " llech. sur la Morphologie du Carpe chcz les Mammifcres," Arcb. de Biologic, publ. par Van

Beneden et Van Bambeke, v. p. 83, pi. iv. fig. 28 (1884).

FOSSIL AIS'D EECENT LAGOMORPHA. 495

constantly after the foixrth month *. Leboucq considers this cartilaginous nodule of the

human foetus the homologue of the ossicle in Hi/ lobnt.es; both are parts of the

pisiform, the pisiform of human anatomy being, in his opinion, but the distal epiphysis

of the complete pisiform f . In a later paper the cartilaginous nodule is homologized

with the OS trigonum (tarsi) : " je crois done pouvoir considerer ce nodule et I'os trigonum

comme homologues " %, whence it would follow that the ossicle of Hylobates is equally the

homologue of the trigonum.

The ephemeral cartilage of the human embryo has since been discovered in an ossified

condition in a carpus of an adult, and received the name triqueti'um secundariuni §.

Both this cartilage in the foetus and the triquetrum secundarium occupy a more radiad

position than the ossicle of the Gibbon, wherefore it would appear that tliey are not,

after all, the homologues of the latter, and this is proved to be the case by the discovery

by Kohlbrugge of tvo accessory ossicles in the Gibbon. In three specimens of the three

species Ilijlohates leuciscn^, H. (((/Uis, and II. Millleri, an ossicle is situated between the

styloid process of the ulna, the pisiform, and the ulnare. It rests on the processus

styloideus and articulates with it and the ulnare. The pisiform joins the carpus

at the jioint of junction between the ossicle and the ulnare. Kohlbriigge recalls the

description of Daubenton, in whose honour the ossicle is named {ossiculum Dauientonu) ;

and he adds that Camper had seen it in the Inuus ||. In the carpus of a Hylohales

syndactyhts the following condition is described :— " Sitiiated between the radius aad the

ulnare is an ossicle, which is joined to the radius and to the ossiculum Daubentouii by a

fibrous ligament ; between both is cartilaginous tissue." The ossicle which, to all

appearance, is that described by Camper in the Mandrill — and which has hence received

the name ossiculum Camper ii — was present in both hands of the Gibbon ; in the left

manus the ossiculum Daubentonii was reduced to a small osseous nucleus ^. From its

position, the ossiculum Camperii corresponds to the cartilaginous nodule discovered by

Leboucq in the human foetus, and is therefore the homologue of the triquetrum

secundarium (triangulare) of Man **. There can be no doubt that the ossiculum

Daubentonii is the element Avhich Leboucq has described in an adult II. leuciscus, since

they occupy the same position. In Leboucq's figure — doi-sal aspect of the carjnis — the

pisiform (jj.) has been removed backward, in order to bring it into evidence ff.

* Op. dt. p. 81, pi. iii. fig. 17. t Op. rlt. p. 83.

i H. Leboucq, " Sur la Morphologic du carpe et du tarse," Aiiat. Anz. i. p. 20 (]88(i).

§ Pfitzner, " Eemerkung-en zum Aufbaii des monschl. Carpus," Verb. Anat. Ges, 7. Vers, in Gijttingen 1893

(Ergiinzungsbeft Anat. Anz. viii. p. 191 (1893).— See also Morph. Arb. iv. p. 508 (189.5).

[| J. H. F. Koblbriigge, " Versueb ciner Anatomie d. Genus ffi/lohates" (M. Weber, Zool. Ergebn. eiuer Eeise iu

ISfiederlandiscb Ost-Indien, i. pp. 338, 339, pi. xvii. fig. 9 (1890-91).

If Op. cit. p. 339, pi. xvii. fig. 10.

** Tbe ossiculum Camperii (triquetrum secundarium, triangulare) or. as Thilenius terms it, os intermedium ante-

hrachii, has been found in Homo, Bi/Iobates, and Ininis, as mentioned in the test, and, by Pfitzner, in a carpus of

PliascoJomys. Pfitzner's specimen is figured and described by Thilenius (Morph. Arb. v. p. 9, pi. i. fig. 12 (180.5)).

I find -what I take to be the same bone in Lemurs, Insectivora, and Piodentia, -nbereon more will be said in another

place. (See P. Z. S. London, 1899, pp. 428-437.)

tt Oi'. cit. p. 101 (explan. of fig. 28).

496 r»R. C. I. FORSYTH MAJOR ON

I.eboucq's view that the human pisiform is the homologue oi^ the mammalian pisiform

minus the ossicle he figures in the Gibbon receives confirmation by a discovery of Pfitzner's

in the human adult carpus. He found in five cases a proximal process of the pisiform*.

To this " jiisiforme secundarmm " would correspond the " uhiare antebrachii " of Thilenius,

met with in ten manus of five embryos, where it is situated volad and ulnad of the proc.

styl. ulnai, and proximally from the pisiform f . Both German authors take this element

to belong to the same category as the os Camperii, viz. to be a carpal of a " preproximal

series." We have, however, seen that Leboucq shows that the os Daubentonii, which in

Hijlobutes is not unfrequently an independent ossicle, is contained in the mammalian

pisiform. For my part, I see no stringent reason to assign this os Daubentonii to a

"preproximal" series; from its position I consider it to be the first, proximal, carpale of

the fifth ray, and it might therefore appropriately be designated as V. 1 ; it corresponds to

the 1. 1 on the radial side, the radiale marginale, which in Echidna actually articulates with

the radius (Owen). In Eeptilia, especially in Emydidae, we frequently find an ossicle or

a cartilage occupying the position of a V. 1. Its absence in the Urodela is easily explained

by the reduction of the ulnar part of the urodele carpus, even the fifth digit being lost.

The reduction of the ulna and the ulnad extension of the ulnare may account for its

being, in Mammalia, generally situated on the volar face.

What, then, is the distal part of the mammalian pisiform ? One might suggest, as the

easiest expedient for getting rid of this embarrassing element, that it is V. 2, viz. the

second car})al of the fifth ray.

But, besides there being, as we shall see hereafter, another competitor for this distinction,

there is not the slightest evidence of the distal pisiform having at any time occupied a

similar position. On the other hand, it shows evidence of a former greater complexity.

In most, if not in all Mammalia, except Man and the Anthrojioids, the pisiform is

provided with a distal epiphysis; and in some there is more than that. In the Hodent

Bathyeryus mariUnms, as described by Von Bardeleben, "... the iJrsepollex and the

postminimus are both very well developed. The latter consists of two bones, of which

the proximal {pip.) is the true pisiform, and measures 5 millim. in length, while the

distal is 7'5 millim. in length. We must therefore in the future distinguish a proximal

from a distal 'pisiform,' and I regard the former as, in all probability, the carpal, and

the latter as the metacarpal segment of the postminimus " J.

Two skeletons of Bathijergus maritimus are in the Natural History Museum, neitlier

of them quite adult. In the older one, which is the original of Voa Bardeleben's figure 3,

the distal part of the pisiform is incompletely ossified, as showm in the figure ; it is still

completely cartilaginous in the younger specimen. A similar, more or less ossified distal

* Morph. Arb. iv. p. 508 (189-5). " Dieser Fortsatz war (in vier Fallen) proximal, utid zugk-it^h eher etwas

dorsal als volar gerichtet. .Seine plane Fliiche stellt eine coiitinuierliche Fortsetzung der Gelenkfliiclie des

Hauptstiicks dar ; im tjbrigeii war der Fortsatz riugsberum duroh eine tiefe Einziehung abgesetzt."'

t Morph. Arb. v. p. 470 (189G).

X " On the rroepollex and Pra;hallux, with observations on the Carpus of Thei-iocksmus phylarchus,'' Proc. Zool.

Soc. London, 1889, p. 260, pi. xxx. fig. 3, pi.p.^pi.d. ; id. Verb. Anat. Ges. 3te Vers. Berlin (Ergiinzungsheft) Anat.

Anz. iv. p. 108 (18S9).

FOSSIL AND RECENT LAGOMORPHA. 497

pisiform I find in tlie liys-tiicine Cfenomys and in Mus, and it will probalily be met with

in many otlier fossorial and climbing Rodents.

What seems to be a remarkable adaptation of the distal pisiform to a special function

is exhibited l)y the strong cartilage, whicli in Fteromys is prolonged to support the

lateral membrane serving as a parachute. Thilenius makes of it an element of an

antebrachial series, his " ulnare antebrachii " * ; but he is misled by Owen's much reduced

figure of the skeleton of a " Fteromijs voluceUa "f, in which the detached cartilage has

been drawn proximally to the pisiform and separated from it by a small interspace.

The true connection of this cartilage was already known to Buffon %■ He described it as

a bone ; but in the only skeleton {Pteroyuiis m<(gnificiis) at the Natural History Museum

in which this element is preserved it is perfectly cartilaginous, and as such it is described

by Owen in Sciuropterm coliicella §. In Pteromi/s magnificus it is chiefly attached to the

distal end of the pisiform, and, by a much smaller process, to the tuberosity of the fifth

metacarpal. Its direction is in the beginning right backward, in the prolongation of the

long axis of the osseous pisiform ; but gradually it turns upward, forming in its entirety

a semicircle. It might be maintained that the patagial cartilage of Sciuropterini is in

origin quite extraneous to the pisiform, and that it has only secondarily become supported

by this widely projecting bone. With the scanty material at my disposal, I am not in a

position to follow up the matter closer, nor is this the place to do so. A clue might be

obtained from young specimens of ttercmtjs; and if they should show both the usual

pisiform epiphysis and the patagial cartilage, they would support the view of an extraneous

origin of the latter.

The lengthened subcylindrical bone which in the insectivore Cht'ijsochloris extends

from the carpus to the humerus, " simulating a third antebrachial bone," was considered.

by Meckel ||, followed by Cams ^, Peters **, Giebel ff , and Dobson %% as an ossification of

a tendon ; regarded by the latter three as that of the m. flexor digitorum profundus.

Cuvier §§, ^l. Wagner || H, Gervais^^, and Owen*** homologize this bone with the pisiform.

* Morph. Arb. (Schwalbe) v. p. 508 (1895).

t 'Anatomy of Yertebnites," ii. p. 385, fig. 154 (18611).

i; "II y a de plus dans le polatonche im os (AA) lon,a de 5 lignes, en forme d'aivte ou d'eperoii. qui tieut au

(|uatrieme os du premier rang du carpe, of qui s"etend oljlicjuenienf en arriere et en liaut le long du bord de la

membrane qui forme les ailes de eef animal." (Hist. Na( . gon. et partic. x. p. 11:3, pi. xxiv. 17():>.)

§ L. e.

II System d. vergl. Anat. ii. (2) p. 374 (18:25). He ealls tbe element " ein voni Streekknorren des Oberarmbeins

zum Speiebenendo [it is, bowever, on the ulnar side] der Ilandwnr/.el gehendes, starkys, verknijcbertes Band.'"

^ " . . . ein drifter Knochen des Untergliedes, welcher jedocli nur als eiue yerkniiehcrte Sehne, oder vielmehr ganz

verknocherfcr Muskel (fle.vor carpi, nhiaris), anzusehcu is'."' — C. G. Carus, Krlauteriingsfafeln zur vergleichenden

Anatomie, ii. p. :')1, Taf. it, fig. Ill, //' (18l'7).

** W. Peters, iS"atur\v. Eeise uacb Jlossambique, Zoologie, i. p. 72 (1S52).

+t Giebel, in Ijronn's Klassen u. Ordnungcn, vi., v. p. 534 (1879).

jj G. E. Dobson, 'A Monograph of the Inseetivora," ]). 121 (1882).

§§ G. Cuvier, Lecjons d'Anat. Comp. 2'' ed. i. p. 42i; ( 1S35).

illi Schreber's ' Saugthiere,' Suppl. ii. p. 12(1 (1841).

^T P. Gervais, Hist. Nat. des Maramileres, i. ]). 252 (1854).

*»* P. Owen, ' On the Anatomy of Vertebrates," i. p. 392 (18GG).

SECOND SERIES. — ZOOLOGY, VOL. VIL 69

498 DR. V. I. FOESYTH MAJOR ON

From the description j^iven by Dobson, it becomes quite evident that from the distal

end of this l)one there arise tendons for the fonr digits, so that we have here a bone

functioning as the commoTi tendon of the flexor digit, prof. Fronr this, however, it does

not necessarily follow that it is an ossified tendon. (The pisiform of Man is imbedded

in the tendon of the m. nlnaris internus ; but scarcely any anatomist will to-day

persist in considering it to be a tenontogenous sesamoid. It has been degraded to

play the part of a " sesamoid " *, and that only in Man and some of the Anthropo-

morpha.)

Dobson has figured the volar aspect of the carpus of a Chrysochloris Trei-ehjaiii^, in

which the alleged ossification of the m. flexor prof, tendon has been removed. Here we

see. uhiad from the lunar, the flattened face of a bone [us.), which is not referred to in

the text; in the explanation of pi. xiii. fig. 5 it is termed the "ulnar sesamoid." Carus J

luxs seen and described this ossicle, and so have D' Alton sen. & juu. § The first-named

states that the " ossified tendon " starts (" ausgeht ") from it ; both Cams and the D'Altons

call it a pisiform (" Erbsenbein") ; but, so far as 1 am aware, later autliors, with

the exception of Dobson, have overlooked it.

In a skeleton of Chrysochloris aurea, this so-called sesamoid articulates dorsad with

the ulnare, dorsad and radiad with tlie lunar, proximally with the ulna, volad and distally

with the " flexor dig. prof, ossification." The latter shows at the dorsal side of its distal

base two facets, the larger ulnad one for tlie " ulnar sesamoid," the smalhn- radiad for a

volar and distal projection of the lunar.

I take this " ulnar sesamoid " to be the ossiciilum Daubentonii, viz. the basal part of

the pisiform ; but, owing to the distorted condition of the Chrysochloris carpus —

the lunar articulates with both radius and ulna— and from my insufficient material,

w^hich consists in a single skeleton of one of the smallest species, I cannot state my case

with greater certainty. If my vie\v is correct, then the " tendon ossification " is in all

likelihood the homologue of the distal part of the pisiform of other Mammalia, where it

very often starts backward at right angles from the long axis of the limb, sometimes,

as in Hylobates ||, directly downward, and sometimes more or less upward, viz. in

a proximal direction [Talpa). Which is tlie primitive direction I cannot for the 2iresent

decide. The Chrysochloi'idae vary so much from one species to the other that Cope

has divided them into three genera % ; and we may hope that it will be possible to settle

the question of the homology of this curious bone when the skeletons of these diff'event

forms shall have become available for comparison.

It appears to me that the distal part of the pisiform will prove to be a remnant of a

lateral ray, which only secondarily entered into connection with the ulnare and the ulna.

Of this lateral ray the other accessory distal elements of Bathyergus, Cieiioii/ys, Mm, and

» n

' Das Pisiforme spielt . . . die Uolle eiiics in der Sehne des Miiskols (Jlexor curpi idnaris) bcfindlicheu Sesani-

beiijs," (jegenbauv, Lehrbuch d. Anatomie des Menschen, 6tc Autl. i. p. 422 (Ifidit).

t 'A Monograph of the Insectivora,' pi. xiii. fig. ii (lS8l!). J L. c.

§ E. D'Altou d. Ae. und E. D' Alton d. J., ' Die Slielete dor Chiropteren und Insectivoreii," p. 22 (1831).

\\ Kohlbriigge, /. c. fig. 10.

^ ' Araei-ican Naturalist,' xxvi. p. 126, footnote 1 (1892).

FOS.SIL AND EECEXT LAGOMORPHA. 499

even the cartilage of Sciuropterini, possibly were parts. There is not tlie slightest

evidence that the lateral ray lias ever been a digit of the manus of the Tetrapoda.

Carimie 5 (V. 3).

Tlie question whether there is some ground for assuming a central carpale (V. 2) in

the fifth ray is closely connected with the present subject, so that it will be dealt with

in this place.

I have known for a long time a comparatively large facet on the proximal ulnar

side of Metae. V in two species of tlie fossil Prolagus, P. oeningeusis (Kon.), and

P. sarrhis (Wagn.) (PL 38. fig. 19, v), for wliich I could not account, tlie metacarpals of

Lepus, which were at ray disposal at the time, showing notliing of the kind. This same

facet I have of late found to be present in Lagomys {L. rufescens), where it articulates

with a small ossicle, wliich also jiresents a facet to the ulnare (PI. 38. fig. 4, v). The

ossicle is likewise present and has the same connections in St/ /ri fag /is brasUiensis (text-

figures XXIX & XXXI), S. sp. from Bogota (PL 38. figs. 1, 2, c), and Orgclolagn.s crassi-

caudatus (text-figures XXXIII & XXXIV). In two otlier sj^ecies {Nesolagiis Netscheri

■And. Caprolagifs hispidas) the facets are visible, but the ossicle has been lost.

What is the ossicle in question ?

As is well known, Gegenbaur was the first to express the opinion that the mammalian

hamatum is a compound of carpalia 4 and 5, on the ground that in lower forms we find

the fourth and fifth digits provided each with a separate carpale *. Leboucq sees in the

mammalian hamatum the homologue (jf carpale t only. " Le carpien 4 + 5 de Gegenbaur

ne correspond exactement dans les premiers stades de developiiement qvi'au metacarpien

IV seul; le metacarpien V est place lateralement par rapport a ce carpien. I,e carpien

4 + 5 se separe de I'axe an niveau de Lintermcdiaire ; quant au V"* metacarpien, tout fait

supposer que son rapport avec le dernier os de la rangee distale est secondaire chez les

mammiferes ; primitivement c'est toujours avec le IV" metacar2)ien seul que ce carpien

est en continuite. On ne voit a aucun stadc^ de developpement ce carpien forme de

deux parties, ou presentant le moindre vestige de sa double origine. Oil serait alors le

carpien 5 ? En examinant les premiers stades de developpement, non-seulement chez

rhomiue, mais chez les divers mammiferes que j'ai pu etudier, on voit que le metacarpien

V est place en face de I'os cubital, mais separt^ de lui par un interstice pUis grand que

celui qui sejiare les autres metacarpiens de leur carpien correspondant. On pent

admettre que c'est au niveau de cet espace que doit se trouver le carpien 5. Quant a

determiner ce qui doit representer ce carpien, on pent admettre son absence complete,

ou bien le considei"er comme non differencie, et contenu virtuellement dans un des

elements squelettiques du voisiuage : soit I'os cubital, soit le metacar2)ien V. L'hypotjiese

la plus probable serait de considerer le carjiien 5 comme ne s'etant pas diiierencie a

I'extremite proximale du metacarpien V " f.

* U)it<.Tsuchuiigen z, veigl. Anatomie d. AVirbdthiure, i. pp. 45, 53, 121 (1^U4).

t " liech. sur la Morpholugie du Carpe chez les MamniLleres,"' Arch, de Biologic, publ. par E. van Benedeii et.

C'h. van Uambeke, pp. Ul', 93 (1H84).

09*

500 DE. C. I. FORSYTH MAJOR ON

In the following year Turner described and figured five distinct distal carpal bones in

a Whale. After having mentioned that in 3Iesoplodo)i hldeiis " carpalia 4-1-5 formed a

single bone .... which was grooved on its dorsal surface opposite the interval between

metacarpals IV and V," he proceeds to describe the carpus of an adult Hijperoodon

rostratus. " Tlie distal carpalia are five distinct bones, not so regularly faceted as those in

the proximal row, and with a larger proportion of cartilage between them. These bones

pass from the radial to the ulnar border in regular order, as C 1 to C 5, and each is

associated with the metacarpal bone of its corresponding digit. A similar arrangement

exists in both limbs, and the carpus possesses also an elongated pisiform cartilage, which

in one is partially ossified " * .

Von Bardeleben had previously made the following statement : — " Deutliche Anzeichen

einer friiheren Trennung in zwei Elemente zeigt das Hamatum bei den Beutelthieren,

weniger auff'allend bei den Nagern, sowie bei Ziphiiis {Hyperoodon). In zwei Stiicke

getrennt, abcr, auf der einen Seite wenigstens, schon im Verwaclisen begrilTen, ist es an

dem Skelete eines jungen Baren in Berlin." t-

To these assertions Baur replied that he had never in any mammalian embryo observed

the hamatum to be the outcome of a fusion of two elements, and he adds : — " Wenn es

l)ei iilteren Thieren den Anschein hat, als ware eine Tbeilung vorhanden, so ist dies eben

etwas secundiires und ist morphologisch nicht verwendlmr " %. In his latest utterances

on the subject §, Von Bardeleben mentions (mly the separation of the hamatum in

" Ziphius {llyperoodon)^'' thus tacitly withdrawing the statements regarding other

Mammalia, made at the meeting of the Jenaische Gesellschaft of May 15, 1885, above

quoted, as %\ell as in a subsequent meeting of October 30 ||.

The manus of the Jena specimen of Ziphins cavirostris, to wliich Von Bardeleben

refers, has been described and figured by Kiikenthal. It contains altogether three distal

carpalia : the one resting on Metac. IV and V shows on its dorsal surface a delicate

furrow, " eine zarte Furche als Andeutung einer friiheren Trennung zweier Carpalia" ^.

This is what Von Bardeleben, in Ids " Referat," calls having found in Zipliim " eine

natiirliclie Zerlegung des ' Hamatum ' in das Carpale IV und Carpale V " **, and further

on : " Dass Ref. im Mai 1885 die primitive (vielleicht secundare — jedenfalls dem

Verhalten bei Urodelen entsprechende) Trennung des 'Hamatum' oder Carpale 4-f-5

(Gegenbaur) in Carpale I und Carpale 5 Ijei Ziphius cavirostris autfand (an der Hand des

Jenaer Exemplars)." ft.

In his subsequently-published researches, Kiikenthal describes fresh facts and sums

up those previously recorded %%. In embryos of Beluga and Monodon there sometimes

* Journ. Anat. Physiol, xii. pp. ISO, 183 (188(3).

t Jeuaische Zeitschr. f. Naturw. xix. (xii.), Suppl. ii. p. 87, Sitzung urn l-j. ilai 188.5.

J Zool. Auz. 1885, p. 487.

§ Proc. Zool. Soc. London, 1894, p. 375 ; " Hand und Fuss," Verh. d. .Inat. Ges. viii. pp. 2()3, 301 (1894).

;i Jen. Zeitschr. xix. (xii.), Suppl. iii. Sep.-Abdr. p. 78 (1885).

•U Denksohr. d. nied.-naturw. (tes. zu Jena, iii. pp. 38, 4G, pi. iii. tig. 18 (1889). See also E. Rosenberg, op. cit.

p. 2, footnote 4 ; Kiikenthal, in Morph. Jahrb. xiv. p. 50 (1893).

** Op. cit. p. 203. tt 0/:<. C't. p. 301.

Xt Denkschr. med.-naturw. Ges. Jena, iii. pp. 208-280 (1893).

FOSSIL AND RECENT LAGOMOEPHA. 501

occur five carpalia. An additional instance of five carpalia in an adult Hyperoodon is

adduced from a specimen in the Royal College of Sui'geons *, and two examples in

enabryos of the same genus f . The reduction in the number of carpalia is explained by

fusion or vanishing (" Schwund ") ; the fusion is brought about in two different ways : —

" Bei den Ziphioiden verschmilzt das Carpale distale 5 mit dem C. dist. 4, es kommt also

zur Bildung eiues Hamatums ; bei den Belphiniden verschmilzt das Carpale distale 5 mit

dem Ulnare, oder aber es kommt iiberhaupt zu einera volligen Schwunde des ersteren,

und seiue Stelle wird vom Ulnare eingenommen." Transitions between both types of

reduction occur in Beluga and Monodon.

In an embryo of JEmys littana, of 8 mm. length, Rosenberg found in the place of

one hamatnm two completely-separated cartilages. "Der melir ulnar gelegene ist etwas

kleiner und steht ausser mit dem Ulnare und seinera radialwiirts <?eie2:enen Nachbar-

element nur mit dem Mete. IV in Beziehung. Der andere der in Rede stehenden Knorpel

trjigt das Mete. IV; in seinem dorsalen Abschnitt wird er auch von dem Mete. Ill

lieriihrt, welchem iibrigens sein eigenes Carpale zukommt. Es ist kein Zweifel, dass

diese beiden ovoiden Knorpel die zu postulirenden Carpale 4 und Carpale 5 sind, die in

typischem Verlialten zu ihren Metacarpalien vorliegen . . . es stelleu daher das Carpale 4

und Carpale 5 in diesem Stadium volkommen selhstandige Elemente dar." In three

larger embryos (TO mm.) the same investigator observed three stages of fusion of the

carpalia in question. He considers that this result supports Gegenbaur's view with

regard to the hamatum of Mammalia %.

Pfitzner has given the name Os Ve.mJiainim to an ossicle in the human carpus, first

described by Vesalius, who considered it to be a sesamoid. It is situated on the ulnar

side of the hamatum, and its distal facet touches the tuberosity of the fifth metacarpal §.

Later on, he mentions two other cases in Man, one found by Gruber || and a third

by himself ^. In Vesalius' case, the ossicle articulated apparently with the hamatum and

Metac. V. In Gruber's case " begann es vom Hamatum abzuwandern und sich dem

Met. V enger anzuschliessen, mit dem es wahrseheinlich schon coalescierte." In

Pfltzner's own case finally, the ossicle had no more connection with the hamatum, and

had undergone a synostosis witli the Metac. V. Pfitzner continues : " Als weitere

Riickbildungsstufen haben wir wohl anzunehmen, dass es vom Met. V giinzlich assimilirt

wird iind in dessen Tuberositas aufgeht," a view which is confirmed by what Thilenius,

who terms this element " Carpo-metacarpale 8," has foimd in the human embryo **.

Pfitzner is of opinion " dass in gewissem Siune das Os Vesalianum, namentlich in seiner

urspriinglichen Lage, einem hypothetischeu Carpale V zu entsprechen vermochte."

Like their predecessors, neither Pfitzner nor Thilenius have met in the human carpus

with a division of the hamatum into a carpale 4 and 5, in Gegenbaur's sense.

Pfitzner's os vesalianum carpi occupies about the same position as the ossicle in

* Ihid. p. 27S, text-fig. 11. t Ihid. text-figs. 12, V-i.

X Jlorph. Jahrb. xviii. pp. 8, 9 (1892).

§ Morph. Arb. i. p. 756 (1892).

II Arch. f. Anat. Phys. pp. 499, 50ii, Taf. xii. (1870).

f Morph. Arb. iv. p]i. 543, 544 (lb95). ** lb. v. pp. 4SS, 489 (1890).

502 DR. C. I. FORSYTH MAJOR ON

Lagomyidae and Leporidae mentioned above. I am not aware that it has ever

been recorded before in lagomorj^hous Rodentia ; while it seems qixite a common

element in Mammalia jirovided with a Avell-developed fifth digit, at any rate in

E-odentia, Insectivora, and Edentata, and Avas known to the older anatomists. Cuvier

mentions it in the Great Armadillo {Priodon (/igcmteus), and describes and figures it

as situated laterad of the ulnare and articulatins; with the Metac. V *. In the fio:ure

jjublished by .Flower f, it would appear to articulate with the ulnare as well. As to its

presence in Rodentia, Cuvier remarks : " Eufin il y a tres souvent aussi au. bord externe

du carpe, en dehors du cuneiforme et de lunciforme, un os sumumeraire, petit et lenti-

culaire ; on le voit dans le castor, le pore-epic" ^. It is figured in a carpus of the

Castor ^. In the ' Lecons d' Anatomic comparee,' mention is again made of this " os

surnumeraire " in the Hystrix: " . . . il y a un os surnumeraire entre le jnsiforme et

I'os metacarjjien du cinquieme doigt ; il est attache sur I'os crochu" ||.

Thilenius ^, quoting Cuvier's figure of the Castor carpus, is inclined to consider this

ossicle as his (Thilenius's) " ulnare externum " = the ulnar part of Ptitzner's triquetrum

bipartitum of the adult, found in the human embryo **. He adds, however : " Infoige

der radialen Verschiebung des Carpale (4 + 5) erreicht es indessen audi das Metac. V."

The question is whether, when an os vesalianum is ])resent, the hamatum is really

displaced, or is not rather in its original position; only secondarily either supjjlanting

the vesalianum, or acting in a compensatory manner for it, when the latter is either

displaced or has disappeared. When comparing Thilenins's figures 11 and 12 of this

" ulnare externum " ff with figures 13 and 11 %%, representing a later stage, the impression

is conveyed that in the latter this ulnare externum {ue) has been displaced proximally

by the ulnad extension of the hamatum. A secondary jjj'o.rimal displacement of a carpal

(or tarsal) would, however, be quite unusual, and Thilenius has expressed some doubt §§

whether the figures mentioned all represent the same bont;. In fig. 11, where ne abuts

upon Metac. V, the former element might be Pfitzner's vesalianum (carpo-roetacarpale 8,

Thilenius). The text-figure XXXIV of the present paper seems to exclude the

possibility, ventilated by Thilenius || ||, tliat '-vesalianum" and "ulnare externum" —

which have not yet been found together in the same manus of Man — might represent

one and the same bone. The enormous ulnad and volad expansion of the ulnare,

as shown for the Lagomorpha in this figure (XXXIV) — which occurs in other Mammals

also — leads to the assumption of its being a compound of an ulnare -j- ulnare externum

Thilen. The "ulnare externum" ( = ulnar part of triquetrum bipartitum Pfitzn.) would

then be the second (central) carpale of the fifth ray (V. 2).

Meckel has described the os vesalianum in Erinacens -. — " Der lyel hat in der obern,

weit breitern Ordnung oier Knochen. Kahn- und Mondbein sind zwar verwachsen,

* Oss. loss. V. 1, p. 127 (1^23).

t ' An Introduction to the Osteology of Mammalia,' 3rd ed. tig. IIU " «," p. 307 (1885).

+ Oss. foss. V. 1, p. 48 (1823). § Ih. pi. ii. tig. lU.

II Lerons d'Anat. comp. 2de cd. i. p. -127 (1835).

^r Morph. Arb. (Sohwalbe), v. pp. 508, 509 (1S90).

** Morph. Arb. v. pp. 473, 474 (1S96).

tt Morjjh. Arb. v. pi. xxi (1896). ++ Ih. §§ Ih. pp. 489, 508. |i || lb. p. 489.

FOSSIL AND RECENT LAGOMORPHA. 503

allein das grosse dreieckige Eein triig-t aussen und vorn einen kleinen, runden Knocben

cingelenkt, den man ein zwcites Erbsenbein nennen kann. Von den vier vordern

ist das Ilakenbein weit kleiner als gewobnlich, und das dreieckige stosst daher aussen

betrachtlicb ^veit an den fiinften Mittelhandknochen" *.

Owen mentions the same ossicle in the Hedgehog, but more distally : — " A sesamoid is

attached to the outside of tlie base of the metacarpal of the digitus minimus " f. In

a left carpus of Erhiaceiis rnropfPiis lying before me, the ossicle articulates with both

the ulnarc and Metac. V, the facet for the latter being smaller and, as in Prlodoii,

situated ulnad from the ulnare. The same bone is mentioned in Gymimra by Dobson |.

Eeferringto this ossicle, Leboucq says : — " Ce qu'on appelle 2'" pisiforine, existant chez

quelques mammiferes (h(?risson, tatou, etc.), n'est qu'un sesamoide developpe dans le

tendon de Textenseur cubital du carpe" §. It may be a matter of surprise that, in the

same chapter in whicli Leboucq insists with strong argunu>nts tliat the pisiform cannot

he classed among " les os sesamoides," he casts aside with a few passing words this

equally imjioitant bone. The exj)lanatioa is to be found in the words " chez quelques

mammifei'es ; " the autlior being evidently not sutficientiy acquainted with the " os

vesalianum."

Having placed the facts before the reader, I have now to sum up. All the attempts

(Leboucq, Baur, Rosenberg, Pfitzner, Thilenius) to trace ontogenetically the pre-

sumed fusion of carpalia 4 and 5 to form the " hamatum " have confessedly failed.

Geijenbaur explains this negative result by sujiposing that the ^lammalia inherited

the "hamatum," from lower Vertebrates. This leads him U) the assumption that the

occasional occurrence of two separate carpalia (i and 5) among Cetacea is secondary ;

the more so as we find other very considerable changes in the manus of these

animals || .

To this argument might be opposed the daily increasing luunber of instances

brought forward in which we sec primitive characters occurring precisely in those

species, or in those organs, which in other respects are highly differentiated (specialized),

the preservation of old characters l)eing obviously due to the specialization of others.

This by no means new truth was, if I am not mistaken, first enunciated by Haeckel.

In support of the foregoing, I wish to refer to a very noteworthy remark by Gegenbaur

liimself. In defence of certain conclusions arrived at in his well-known " Gliedmaassen-

skeiet der Enaliosaurier " ^, he states that in Sauropterygia and Ichthyopterygia the

* System d. very;!. Aiiat. ii. 2, pp. 3iJ3, :^94 (181^5). t ' Anatomy of Vertebrates,' ii. p. 390 (18G6).

X ' A Monog-raph of the Insectivora,' p. 21 (1S82). § Areh. de Biologie, v. p. 84 (1884).

II " Die Eiiiheitlicbkoit des lIuiiKitmn der Siiiigethiere ist voii mir al.s ein auf dem Wcge der Thylogenese

erworbener Befund erklart wordeii, da in niederen .Vbtbeilungen der vierto und fiinfte Finger je ein discretes

Oarpalstuck besitzen. Da jcner Erwerb durch Concrescenz bald auf die Siiugetbiero libcrging, moobte ich bezweifeln,

dass ira Carpus der Cetaceen der uicdere Zustand nocli zu erwcisen ist, selbst weim auoh unter den vielerlei dort

bestehendcn Befundeu ein Carpale 4 und ein C'ar[)ale 5 sicb darstellt. Denn die iibrigon Veninderungen sind in

diescm Handabscbuitto zu bedeutend, als dass eiu seamtUh- crfolgtes Zustandekommen eiues dem uraprungiieben

ahnlicben Vcrhalteus zweier distaler Car[)alia ausgeschlossen ware."' (C. Gegenbaur, Vergl. Anat. der Wirbelthiere,

i. p. 542, 1898).

^ Jen. Zeitschr. v. (1870).

504 DR. C. I. FOESYTH MAJOR ON

adaptation to a new function does not in any way explain the typical features of their

limbs. " Where we meet with similar adaptations, the original condition has never been

completely effaced " (italics mine) *.

The undivided condition of the " hamatum " in terrestrial Mammalia can now be

explained in a very simple and obvious manner, since by means of the " os vesalianum "

we are enabled to sliow that the presence of a separate carpale 5 is not in the least

limited to af evv cases among Cetacea, but is a frequent occurrence in other Mammalia

likewise, a circumstance which has hitherto either been wrongly interpreted or entirely

overlooked. Tlie " hamatum " of Mammalia is not carpale 4 + 5 of Reptilia, but it is a

carpale 4 which, as a rule, has become enlarged, and has, in addition to its own functions,

usurped those of carpale 5. Whether a usurjDation is in ecery instance to be assumed

is another question, which cannot be entered into here ; it may, for the present, be

sufficient to repeat that the suj^eradded function of carpale 4 may often be not the

cause but the consequence of the degradation of carpale 5.

Where carpale 5 is absent in the terrestrial Mammalia, it has, so far as my experience

goes, either disappeared by atrophy, or become absorbed by the tuberosity of Metac. V,

as in Man. Finally, therefore, since the fusion of carpale 5 with carpale 4 has never

been observed in these, its occurrence may be peculiar to the Cetacea.

Hem ARKS ON the Metatarsus and Tarsus of LAGOMORrflous Eodentia.

1. Motatarsale I and Tarsale 1. — Krause states f that in adult E.abbits the os tarsale 1

becomes fused with the os Metatarsi I, and for this he refers to his text-tigure 6i B.

He continues as follows: — "In new-born animals, however (fig. 64a), the tibial

prominence of the proximal extremity of Metat. I is independent, and consists of an os

tarsale and a lengthened distally-pointed bone, representing a rudiment of the hallux,

at tlie distal end of M'hich there is inserted the tendon of the m. tibialis anticus. In

reality, therefore, the os tarsale 1 of the Rabbit is the o.t. 2 of Man, and the os

Metatarsi I of the Rabbit represents the os tarsale 1. the hallux and os Metat. II of

Man." So far as the fig. 64 a, " horizontal section of right hallux of a 12-days-old

Rabbit." goes, this is correct, assuming that the two outline-figures of the tarsalia

(1 and 2) are meant to show them in a cartilaginous condition. But the lettering of

fig. 64 b, " right os Metat. I " (meaning Metat. II of comparative anatomists) of an adult

* " . . . muss daran festgehaltou wcrden, dass die Anpassuiig au eine neue Fuiictiou keiueswtgs das Typische der

Gliedmaasseni'orm zu erklaren vermag. Wo wir .solchen Anpassuiigen begeguen, hat sich der urspriingliche Zustand

nie ganz verwischt. In der Flosse der Baiaenen ist das Saiigcthierarmskclet klar zu erkennen, ebeuso wie bei den

Cheloiiiern die Schildkroteuextremitiit. Hier bei den Fiialiosaiiriern ist aiieli gar niehts auf Reptilien Beziehbares

am Flossenskelet vorhauden. Von der schoii bei Amphibieu vorhandeiien Hifi'erenzirung vou beiderlei Giiedmaassen

iiicht ein blasser Schein ! Es miisste also an der Gliedmaasse ciii RUckgang bis zu den erstcn Aufangen erfolgt

und von diesen her cine selbstandige .\usbildung eingetretcn sein, wenu Reziehungen zum Reptilientypus hier

einmal an der Gliedmaasse bestandeu haben mogeu. JedeiiCalls gehiireu diese Bildungen nielit in die Reihe der

Reptiliengliedmaassen, soudern unter die Anfiiiige, wie sie denii gerade in dem schou bercgten Mangel des Different-

werdens von Vorder- und Hinterextremitiit sogar unterhalb der bis jetzt bekanntcn Reptilien sich stellen. So

birgt sieh iu diesen Fragen ein interessantes Prjblem." ( Vergl. Anat. der Wirbelthiere, p. 531.)

t W. Krause, Anatomie d. Kauiuchens, :^"' Aufl , p. l;i2 (lKS4).

FOSSIL AND EECENT LAGOMORPHA. 505

R bbit, from the medial side, is erroneous. The process T, "place of the real Hallux,"

is the tuberosity of the Metat. II; with this tuberosity neither the tarsale 1 nor

the rudiment of the Metat. I come in contact, and therefore they cannot form a

connection with it. The proximal process of Metat. II, numbered 1 (= place [_SteUc] of

the real os tarsale primum), represents instead the rudimentary Metat. I (see PL 38.

figs. 5 and 6 I), which in young Lepus is distinct, but afterwards becomes fused w'ith

Metat. II. Tarsale 1 is visiljle in the vouns' llabbit in a cartilairinous condition *,

but in this species and in a Sylcilagns fi-om Bogota, in both of which I hav^e been able

to examine various stages, I have neither observed au ossification of it, nor a fusion

W'ith the rudimentary Metat. I, as assumed by Ivrause and by Leche. It gradually

shrinks and apparently is absorbed f. It is quite possible that in some species a fusion

may take place as a rule or exceptionally ; but I deny it to have been demonstrated in

the Rabbit, in which it is said to be the rule. Professor Howes informs me that he too

has searched in vain for evidence of this.

2. Ftision of Tarsale 2 vjith Jlet a tarsale II. — A fact hitherto not noticed in

Lagomorpha is the fusion of tarsale 2, the mesocuneiform (e, of my figures) with

Metat. II. This fusion takes place in Prolagns (PI. 38. figs. 17, 27 a), in Lagoinys

(PI. 38. Hgs. 16, 26 (e,)), and in som^ Leporidse. In Nesulagus Netscheri (PL 38. fig. 23),

the figured specimen of w-hich is not adult, the fusion is not quite complete ; in the older

specimen at the Ley den Museum I saw it was complete. In a specimen of S/jlvilagus

hrasiUeiisis from Lagoa Santa, the property of the Copeuliagen Museum, tarsale 2 is

fused in the right limb and distinct in the left ; in an incomplete limb of the same

species in the Royal College of Science, London, the fusion is complete.

3. Frcecuneiforyne. — As in the case of tlie vesalianum carpi (see pp. 501-3). my

attention was arrested by an accessory bone in Prolagus sardus through a small facet on

the tibial side of the proximal termination of Metat. II, or rather of Metat. I, since, as

shown before, this part is occupied in the young by the rudimentary Metat. I, which later

on becomes fused with Metat. II (PL 38. fig. 1", pe; fig. 27 a, facet on the upper left side

of Metat. II). This is the region which corresponds to the insertion of the muse. tib.

posticus, and therefore the ossicle, indicated by the facet, is tlie so-called distal prte-

hallux, or Baur's " klauenartiges Gebilde." Winge has denied the existence of this ossicle

in Lepus and Lagomijs \, but I have found it in both families, and, as we shall see later,

it has been met with as a rare occurrence even in Ijcpus europccus. In Laijomi/s it

articulates (PL 38. figs. 15, 16, 26 pc) by a smaller facet with the navicular as well,

and lies in the distal continuation of a much larger ossicle (fig. 26, ti), which articulates

with the navicular and the astragalus. The latter is undoubtedly Baur's and Leboucq's

"tibialc" (the proximal ossicle of Von Bardeleben's " prfehallux ").

I find the smaller, distal, ossicle in the following Leporidre, viz. iu Nesolagus

* See Leche, iu Bronu's Klass. u. Ordn. d. Thierr. vi. v. 28"^' Lief. pL xevi. fig. 3 (1S85).

t Retterer (Cump.-reud. et. Mem. Soc. Riol. (lU) i. p. 807, 18!»4) regards the ossicle, whicli I with others hold to be

a nidinientary iletat. I, as tarsale I, deuyiiig- all trace of the foriaer. The presence of a cartilaginous tarsalo 1 in 3'oiing

Rabbits is easj- of observation, but presumably it was not yet chondrified in the stages examined by Retterer.

j H. Winge, " .Jordfuudne og uulevende Guavere," E ilu.seo Lundii, i. p. 1G9 (1857).

SECON]) series. — ZOOLOGY, VOL. VII. 70

506 DR. C. I. FOESYTH MAJOR ON

Netscheri (PI. 38. fig. 23, ^x-) ; in Onjctolagus crassicaudatus (fig. 22, pc), where it

seems on its way to undergo a synostosis with Metat. II ; in Caprolagiis hispidus

(fig. 2^,p>c), where it has shifted its position completely to the volar side of Metat. II ;

in a specimen of Sylvilagus brasiliensis, from the C o^oen ha gen Museum ; and lastly in

the Wild Rahhit, where the ossicle is very small and situated volad as in C. hispidus.

I owe this specimen to Mr. Sherrin, Articulator in the Nat. Hist. Mus., who at my

request dissected some Hahbits' feet, in search of the ossicle in question.

In his careful researches " Ueher den Siiugetier-Pra^hallux " *, Tornier met with this

ossicle in one case only of all the Rabhits' and Hares' feet examined, and great stress is

laid on this isolated occurrence. " Die Lage dieses iiberziihligen Knochelchens beweist

imwiderleglich, dass es selbst homolog ist dem Knochen welcher bei vielen der liisher

untersuchten Tiere der t 1-Medialseite gegeniiber liegt. Da er an Hasenfiissen

individuell auftritt und an jungen Kaninchen- und Hasenfiissen nicht vorhanden ist, so

ist es zweifellos, dass er eine secundiire Bildung ist, und daraus ist mit Sicherheit zii

schliessen, dass er audi bei den Tieren, wo er iramer vorkommt, eine seouudare Bildung

ist " t. And again : " Der muse, hallucis abductor-Knochen kommt endlieh dritteus

zuw^eilen bei erw^achsenen Vertretern solcher Thierarten vor, bei welchen der Knochen

unter norraalen Umstanden weder im Alter noch wahrend der Ontogenese vorlianden ist

{Lepus timidus) | ; bei diesen Individuen ist er — dagegen giebt es keinen Widerspruch — ■

secixndiir entstanden" i^. Therefore, as already stated in the first-quoted passage, he

again asserts that the homologous boue in all other Mammals is equally secondary.

Even if the presence of the ossicle in question, as believed by Tornier, w^ere limited to

exceptional cases in one species of Lepms, the author's arguments w^ould not be

valid. It is one of the characteristics of these reduced " accessory " bones to ossify

very late (Thilenius) ; and its exceptional appearance in L. europccus could, a prion,

be interpreted quite as well in the sense of a disappearing element as in Tornier's

sense. But the presence of this bone as a constant element in Lagomyida3 and several

Leporidae totally changes the aspect of the question. In the more primitive forms of

La"-omor})ha, the ossicle seems always to be present and pi'oclaims itself a reduced

element by its varying size and position. In those Lepoi'ida: — of which L. europceus is

the prototype — which are the most specialized for leaping, we must expect it to be of

quite exceptional occurrence.

The ossicle has been observed in the " Hare" likewise by Pfitzner ||, who calls it the

pnecimciforme. As to whether this and similar accessory bones are to be considered

as "secondary" or "sesamoids," Pfitzner has shown us the way how to proceed^,

viz. that we cannot base our conclusions on the examination of a single specimen

or a few species. The " pryecuneiforme " has been studied by Pfitzner especially

* G. Tornier, " Ueber deaSaugetier-Pniihallux. Eia dritter lii'itrag zur I'liylogciicse dcs iSaugoticrfusses." Arcb.

f. Naturgcsch. 1S91, pp. 115-:i04.

t Op. cil. p. 1^1. + Meaning Lejtus eurupieiis, Pall. § Op. cit. p. 190.

II Moiph. Arb. (Soliwalbe) i. p. 533 (1S92) ; iv. p. 354 (189.5). Prof. Pfitzner lias kindly informed me that the

species is L. eufop)(^vs. Pall.

f LI. CT. ; and Morph. Arb. vi. p. 394 (1S96).

FOSSIL AND EECENT LAGOMOEPHA. 507

ill the Caruivora (wbeve it had been seen by Meckel) ; and of the Polecat alone

he examined seventeen specimens. His conclusions are summed up in the foUowinsj

Avords : — " Skelet und Musculatur variieren unabhangig von einander, da tiudet kein

Ineinandergreifen beider Processe statt, hochstens, und stets uur in beschranktem

Maasse, ein gewisses Nebeneinanderherlaufen Muskeln und Muskelansatze und Skelet

variieren ohne innere Korrelation, und deshalb ist es fiir die Deutung eines bestimmten

Skeletstiickes ganz irrelevant, ob ein bestimmter Muskel sich daran ansetzt oder nicht.

Das Prascuueiforme bleibt das Prai^cuneiforme, ob sich M. tib. auticus oder M. lib.

posticus ganz, theilweise, oder gar nicht daran ansetzt, und fiir die Deutung eines

Skeletstiicks oder selbst seiner Komponenten, also fiir die etvs'aige Frage, ob andere

Skeletstiicke durch Assimilation mit ihm vereinigt sind, bleibt es mxnz frleicho-iltii; und

ohne jede Beweiskraft, welcher Muskel an ilmi inseriert. — Aber auch mit den Biinderu

steht es nicht anders ; auch sie variieren naeli Vorkommen und Ausbildung ohne

Rucksicht auf die Slieletstilcke " *. And Thileuius : " Die Beziehungen, welche die

accessorischen Elemente der chiropterygialen A-Virbeltliiere zu Muskeln, Sehuen oder

Biindern besitzen, sind nicht primiire Erscheinungen, soudern secundiir wiihrend dei-

Ontogenese erworben '" f.

When the " tibiale " is not a separate bone, as in many Rodents, it is considered to be

part of the navicular, the "tuberositas navicularis medialis " (Baur, Leboucq, Emery:};).

It does not seem to me to preclude the assumption of a medial tibiale, which would be a

part or the whole of Emery's " paraceutrale" §, the first element of the second ray (II, 1).

If then the tibiale marginale (or externum) is the first element of the first ray (1, 1), the

suggestion lies not far off that, lilve the distal " priepollex," the distal " pnehallux "

(prsecuneiforme) is the second element (I, 2) of the same ray, but that it has generally

been thrust out of the series.

4 "Accessory ossicles" articulatiiKj with 2Ietatursal V. — On PI. 38, fig. 9, I have

represented the enlarged figure of a right Metat. V. from La drive, a froai the dorsal,

h from the volar side. This is still another instance of a fossil metapodial, presenting

unusual articular facets, for which, for a long time, I was unable to account, for \v<int of

material for comparison.

Tlie ossicle is much larger than the Metat. V of Proliujns ceniiigensis, which other-

Avise resembles it closely, exhibiting the same particulars as do the fifth metatarsals

of Prolagus sardits and P. sardus var. corsicainis. I must leave it undecided whether the

figured metatarsal belongs to Tifaiioi/iys Fontaniiesi or to Lafjopsis eerns, which, judged

from other parts of their skeletons, were both of aljout the same size.

On the volar aspect {h) is seen a large facet, starting from the proximal end and

running obliquely in the direction of the tuberositas lateralis. In LeporidtB I find in the

* Morph. Arb. vi. p. .304 (1890).

t ihid. X. ])p. .J44, .345 (1895).

J: C. Emery, " B(-'itr. z. Entwicklungsgesch. ii. Morph. d. Hand- ii. Fussskelets der Ma'supialier :'' (Somon's

' Forscliungsreisen in Australieii," ii. pp. 394, 395 (1897).

§ C. Emery, " Die Ibssilen Ileste von Archerjcsanrus und Erijops uud ihre Bedeuliing fiir die 3Iorphologie des

Glicdmaassenskelets," Anat. Adz. xiv. pp. 206, 2u7, figs. 3-7 (1898).

70*

508 DE. C. I. FOKSYTH MAJOE ON

corresj)onding part no facet, but instead, either a convex swelling of the region, or in some

cases, on the contrary, a more or less rugose depression. In Lagomys {L. riifesceiis and

L. melanostomus) there is the facet in the same place, and articulating with it a

comparatively large orbicular or triangular ossicle. I think it probable that, in those

Leporidfe {Caprolagus hispidus, C. Netscheri, Sylvilagus brasiliensis) where the corre-

sponding region of the Metat. V is raised to a convex protuberance, the ossicle in question

has become fused wdth the former bone.

A similar ossicle has been met with by Pfitzner iu Carnivora, viz. in Ursiis ai'ctos and '

in Lidra *. I find the same ossicle in Cercojiithecidye, in Mus, and, among Insecti-

vora, in Erinaceus, Gymnura, Myogale, Condylura and Ceutetidse {Limnogale,

Oryzoryctes, Ilicrogale). In the latter, and in Myoyale, it is enlarged transversely and

extends also on to the base of Metat. IV.

Pfitzner homologizes the ossicle in Carnivora with a similar one on the fifth metacarpal

of Primates (os hamuli), and regards these and similar occurrences in the third tarsal

ray (os unci, in Feliti) as carpalia (or tarsalia) which have become " abortive," and have

been secondarily displaced towards the volar side f . The question would then arise

whether we have to consider the ossicle of the Metat. V as pertaining to the fifth or to

the fourth ray ; for from its position — and the same remark applies to the " os hamuli " —

on the tibial side of the Metat. V, and sometimes articulating with Metat. IV also, it may

belong to either. For the present the question cannot be settled ; but since both tarsal

and carpal elements in question are of apparently widespread occurrence, we may hope

to get better acquainted with tliem before long. In the marsupial Permneles ohesula,

Metat. IV and Metat. V have each a separate plantar bone, articulating Avith their

proximal capitulum %.

On the dorsal side of the tuberosity of Metat. V — on the left in fig. 9« — is seen what

appears to be a facet, partially extending to the volar side also. The same facet is

present in both species of Frulagus. It at once recalls to mind what occurs on the

Metac. V of P/-oJagui> and Lagomyti, and some Leporidaj, where carpale 5 (os vesalianum

carpi) articulates with the tuberosity.

A distinct os vesalianum tarsi (Pfitzner) is a very rare occurrence in Man, in whom it

has been seen by Vesalius, Gruber, and Spronck §. Pfitzner never saw it free; when

distinct — one case figured by Vesalius, two described and figured by Gruber, one by

Spronck — it is situated on the fibular side of the pes, " in the angle between the cuboid

and Metat. V, articulating Avith both." An epiphysis which may occur on the tuberosity

* Tageblatt der 60. Vers, deutsch. Naturf. und Aerzte in Wiesbaden, p. 251 (1887). — Speaking of the Bear, the

author states that the ossicle occurs on the plantar base of Metacarpal V ; from the context it would appear that

this is a misprint for Metatarsal V • at anj' rate, in Lutra it is present on both Metacarpal and Metatarsal V, as

stated by the same author.

t Morph. Arb. i. pp. 7, 8 (1S9I) ; 541, 542, 587 (1892) : iv. p. 539-543 (1895).

+ C. Emery, " Beitr. z. Entwicklungsgesch. u. Morph. d. Hand- u. Fussskeletts der Marsupialia" (Semon's

' Forschungsreisen in Australieu,' &c., ii. p. 381, Taf. sxxv. figs. 45, 46 (1897).

§ Morph. Alb. i. pp. 522, 595, 596, 756, 757 (1892) ; vi. pp. 472-475 (1896).

FOSSIL AND RECENT LAGOMORPHA, 509

of the human fifth metatarsal is considered by Pfitzner * as one of the terminal stages

of its assimilation by the latter bone.

I lind an epiphysis on the tuberosity of Metat. V in the Eodent genera Genrychus and

Ctenomys. The bone itself 1 have never seen independent, but, from what I have stated

above as to the fossil metatarsal, there can hardly be a doubt that an ossicle articulates with

the tuberosity. The cuboid of 'Prolagus, of which I have a number of specimens, shows

a facet — absent in Leporidte — on the proximal fibular side ; and this, together with the

facet on the tuberosity of Metat. V, suggests the presence in these LagomyidjB of either

one ossicle articulating distad with the Metat. V and proximad with the cuboid, or two

ossicles, the proximal of the two articulating with the cuboid, the distal with Metat.

V ; both possibly articulating originally also with each otlier at their apposed surfaces.

Considering the ratlier considerable distance which must have occurred between the two

facets, the latter hypothesis — of two bones — seems the more probable.

The presupposed proximal ossicle would be the homologue of the " os peroneum "

(Pfitzuer) of Man f aud other Prioiates, which is the so-called sesamoid in the terminal

tendon of the peroneus lougiis muscle. It has in Man, aeeording to Plitzuer, a frequence

of about S-9 ° '^, ai)(l is situated on the postero-lateral end of the eminentia obliqua <iviboidei.

" Hier findet sich in den Ptillen bester Ausbildung eine scliarf abgesetzte Facette, dereine

gleiche auf dem Peroueum entspricht " %. This os peroneum was seen by Daubenton in

Hylobates : " II y a de plus dans le gibl)on uu liuitieme os place au cote externe du tarse,

a I'endroit ou le ealcaueum touche au cul)oide " §. In the skeleton of a Rylobates lar in

the Natural History Museum, there is to be seen an ossicle articulating with the cuboid;

and it is of quite general occurrence among the Cercopithecidoe. Gillette mentions it in

Monkeys generally as articulating with the cuboid || . Whether the ossicle mentioned

by G. Pischer in the Tursius is a vesalianura or a peroneum I cannot decide for the

present. He says : "Auch findet man in den Taiseni noch ein iiberziihliges Beinchen,

rund, linseuformig, doch liiuglich, Avelches eigentlich auf dem letzten Mittelfussknochen

aufsitzt, der sich immer mit seinem Kopfe weit nach hinten zieht "^. I see the " pero-

neum " in a minute ossicle in Limnogale (an aquatic member of the Malagasy Centetidfe),

adhering to the tendon of the muse, peroneus longus, laterally from the cuboid, and I

believe the reason that it has not been more frequently seen in Mammals is that the

muscle is generally cut away in preparing tlie skeleton.

* Morph. Arb. vi. pp. 262, 203, 474 (1^90).

t Ihld. i. pp. 530, 531, 504-5U8, figs. 12, 13 (1S92) ; vi. pp. 456-462 (1896).

:|: Iliid. vi. p. 456.

§ BufFon-Dauljeiiton, Hist. nat. geu. et partic. xiv. p. 106 (1766).

II " Chez les singes, I'os sesamoide du peronier lateral est tres-volumineux. puisque, ehez des individus de petite

taille, nous I'avons trouve au moins aussi gros que ceux du pouee de rhomme, constant et ayant la forme d'un trois-

quarts d'ovoide regulier ; il possede una face veritablement articulaire, un peu convexe, et qui repond a uuc facette

cgalement encroutee do cartilage de la partie infericure du ouboVdo.'' (Jouni. de I'Anat. et de la Physioloo-ie viii.

p. 533, 1S72.)

^ Gotthelf Fischer, 'Anatomic der Maki,' p. 154 (1S04). This ossicle is not mentioned in Burmeister's ' Beitriio-e z.

niih. Kentniss der Gattung Tarsius ' (1S46).

510 DE. C. I. FOKSTTH MAJOR ON

The "peroueum" would then be homodynamous with the ulnave externum Thil.

(ulnar part of Pfitzner s triquetrum bipartitum),=V 2; and tlie vesalianum tarsi with

the vesalianum cai'pi,=V3, or tarsale 5, the cuboid being tarsale 4.

The cuboid of jMammalia is generally considered to be a compound of tarsale 4 + tarsale

5 ; but where an os vesalianum, or its traces on the tuberosity of Metat. V, are present

such a supposition cannot, however, be admitted. Emery found in embryos and poucli

specimens of the Marsupial genera Didelphys, JEpyprnmnus, and Phascolarctm separate

tarsalia t and 5 *. Por the former genus at least he has demonstrated that tarsale 4

and tarsale 5 become fused in later stages. This instance of a compound Mammalian

cuboid (tarsale 4 and 5) is the only one in the literature which can be taken seriously ;

but it is quite possible that in other Mammalia too the vesalianum uiay be assimi-

lated by the cuboid, instead of by Metat. V, as in Man and some Rodeutia.

Concluding Remarks and Suggestions as to Classification.

The oldest known lagomorjihine genera, Titanomys, and Falceolagas, have several im-

portant characters in common : still, the differentiation into Lagomyidoe {Titanomys) and

Leporida3 {FalcBolcigus) had already taken place. In the number of upper molars and in the

shape and composition of the bony palatal bridge, Titanomys shows itself the precursor of

the recent Lagomys, Palopolagus of the recent Lcpus ; and it is therefore advisable to retain

the two groups as families, although they converge back in time. Moreover, in other

characters — absence of su])raorbital processes, pattern of the cheek-teeth — Palceolagiis

approaches nearer the Lagomyidse than do the more recent Leporid;e. In the gradual

transformation of their cheek-teetli, both groups, as has been amply demonstrated, run

parallel from the Lower Miocene down to recent times. The Lagomyidtii, as at present

known, start from a more primitive type than the Leporidae, since in Titanomys the

cheek-teeth have remnants of roots and the upper ones preserve their original pattern

throughout life ; whereas in Tahcolagiis, so far as I know, the cheek-teetli are already

rootless, and in old age they lose their original pattern, without, however, developing the

new one. In the transformation of their tooth-pattern the Leporidae eventually go a step

beyond the point at which the Lagomyida? stop, the cheek-teeth of Lepus being more

completely metamorphosed than those of recent Lagomys. In this respect, as well as in

the specialization of their limbs for swiftness, correlated with the greater perfection of the

sense-organs — and, as a consequence, witli corresponding modifications of the skull —

the Leporidte are to be considered the more specialized of tlie two ; but there are several

members of the Leporidae which, with regard to the two last-mentioned sets of characters,

and the complete or almost complete absence of the tail, preserve considerable similarity

to the Lagomyidte. By the absence of the upper m. 3, and by some peculiarities of

the cranium, pointed out by Winge (perforation of the fossa pterygoidea — fusion of the

* Atti Ace. Liiicei, Eend. iv. 2, p. 274 (IS&iJ) ; id. in Semon's ' Forschuiigsreiseii in Australien,' &c., ii. pp. 374,

378, 383; figs. 20, 30, 31, 59 (1807).

FOSSIL AND EECENT LAGOMORPHA. oil

spongiose os tymj)anicum with the petrosum), the Lagomyidge are more modernized than

the Leporidge.

If we take for a gnide the gradual metamorphosis of their upper cheek-teeth, the order

of succession in Lagomyidse is : Titauomijs, I'rolagus, Lagopsls, Lagomys. Lafjonii/s is

clearly the offspring of Lago2)sis ; but Lagopsis cannot be descended from Prolagiis, the

latter having lost the last lower molar (m. 3), which is present in Lagopsis {and Zagomgs).

Lagopsis must have taken its origin from a form with upper cheek-teeth like or nearly

like those of Frolagus, but provided witli a lower m. 3, a hypothetical " Frolayopjsis "

descended from Tiianomys or some closely related form with persistent lower m. 3. In

Titanomys {!'. visenoviensis) there is already the beginning of the tendency to the loss

of this tooth. Frolag/is equally descends from a Titauoinys-like form, and has continued

without much change from the Middle Miocene to the present era, since it still lingered

in Corsica at the Neolithic period.

Titanomys

{Prolarjoiis'is) Prolafjvn

La

f/O/K

Laijo)a 1/s

Leporidcc. — Apart from attempts to separate the Eabbit as a genus from the rest of the

Leporida\ which have not, however, met wdth common assent, the family has pretty

generally been considered to be composed of one recent genus only, Lepus. In 181'5, Blyth

proposed a new genus Caprolagiis, for Pearson's Lepus Mspidns*. The appropriateness

of this generic distinction has been contested by Hodgson and by "VVaterhouse. The

former, omitting to take into consideration the remarkable configuration of the skull of

the Hispid Hare, pointed out, that " In the Timid and Red-tailed Hares the long ears,

the large eyes, the frame as well suited to extreme speed as the eyes and ears to effective

vigilance, are certainly in remarkal)le contrast wdth the small eyes and ears, heavy frame,

and short equal legs of the Porest Hare : but all these distinctions, as well as those of

domicile, become less and less tangible in the Variable Hare, the Rabbit, the Tolai and

the Tapiti, in wdiich moreover we have variously reproduced, even to tlie subordinate

peculiarities of the Indian Porest Hare, such as its white flesh, its short tail, its

subterranean retreat and creeping adhesion thereto, so unlike the dashing career of the

* E. Blyth, " Description of Caprolagus, a uew Genus of Leporine Mammalia ; with two plates." Journ. As. Soo,

Bengal, xiv. i. pp. 247-24U (184.5).

512 DE. C. I. FORSYTH MAJOR ON

red-tailed and English species " *. Waterhouse's objections are to the following effect : —

" Strongly marked ... as these distinctions are, if the Assam Hare be compared with

the Common Hare, they are less so when that animal is compared with the Indian Hare

{Lepus rtijicauclatus), and much less so when it is compared with the Lepus bracliyurus

of Japan. This last-mentioned animal has the short ears and tail of the Lepus Jiispidus,

and the same large molar and incisor teeth, combined with a powerfuUy-foi-med skull,

but in this skull the notch which sets free from the fore part of the supraorbital process

is not absent, as in Lepus hispidus : it agrees in having the patch unusually long, but

diflTers from the skull of L. hispidus (as it woiild apj)ear from Mr. Blyth's figures) in

having the zygomatic arches straight and parallel as in other Hares ; the Assam species

having the zygoma somewhat arched outward. The pecub'arities which I have pointed

out as distinguishing the lower jaw of the Lepus riificaudatns from that of the L. timidus

are also found in the lower jaw of i. hispidus, but here the angular portion has a still

greater transverse diameter " t. The result of these criticisms was the withdrawal of

the genus Caj^rokiffus by its author +.

For my part, I am unable to accept these opinions. Some of the remarks of the

former writers are undoubtedly just, and two of the examples of other Leporine species,

adduced by Hodgson, as resembling the Hispid Hare, are more to tlie point than

Waterhouse's comparisons. But the conclusions I infer from them are very different

from those of these authors. The external characters and the conformation of the skull

and limbs, in which the Hisjiid Hare is distinguished from L. europceus — taking this latter

as the type of the genus Lepus s. str. — are very remarkable. The circumstance, which

I shall more fully point ovit hereafter, that there are other Leporines approaching the

Hispid, simply shows that the latter — apart from its specialization as the only true

fossorial member of the family — does not stand alone, and tliat several other species

equally deserve to be separated from the genus Lepus.

The first attempt at a tabular arrangement of the species of Lepus, according to their

affinities, was made by Baird ^, who availed himself of the characters of the skull ; limiting

himself — with the exception of "Lepus cuniculus " — to North American species. The six

sections into wliich the genus is divided sliow that this excellent observer had on the

whole a right conception of the affinities of this group. Not all his sections, however,

are of equal value ; section B, comprising L. califormcus and L. callotis, is in reality

more closely related to A {L. timidus, X. f/lacialis, L. americanus, L. campeslris, &c.)

than to the other sections ; and the same may be said with regard to E {L. Trowbridgei

and L. Audubonii), which, as a matter of fact, is in closer relation with D [L. s^lvaticus

and allies) than with the rest.

With such a good example to follow, a successor, taking up the whole of the known

Leporidse, might have been enabled to make a furtlier step forward. This is what J. E.

* B. H. Hodgson, " Ou the Hispid Hare of the 8aul Forest " (Journ. As. Soc. Bengal, xvi. i. p. o74 (1S-J7).

t G. R. Waterhouse, 'A iSTatural History of the Mammalia,' ii. p. 80 (1S4S).

i E. Blyth, Catal. Mamm. in Mus. Asiat. Soc. Calcutta, p. 133 (1863).

§ Spencer F. Baird, ' Jfammals of North America,' pp. 574, 575 (1859),

FOSSIL AND RECENT LAGOMOliPHA. 513

Gray attem^^ted to do *. From the title of the article, " Notes on the Skulls of Hares

(Leporidte) and Picas (Lagomyida^) in the British Museum," the actual contents could

not be guessed, for the work is an attempt at a complete classification of the Lagomorpha,

in which several characters besides cranial are made use of. The characters assigned

to the family Leporidoe are in part either erroneous (characteristics of the molars), or they

do not hold good for all the minor divisions, and are consequently partly in contradiction

Avith the subsequent cha; ' ^teristics of the sections. This family is divided first of all into

two sections, one reserved for Blyth's Caprola(jus, the other for the rest of the Lejiorida?.

This latter is again subdivided into two groups : — A. Hares, B. Babbits, the latter

containing the Babbit alone, raised to generic rank [Cuniculus). In group A are given

generic names to some of Baird's divisions. The latter's D (ex L. syhaticus) becomes

SylvilagKs, his F {L. aqimticus, L. jx'litstris) Hydrolagus ; while a genus Tapeti is

created for the Brazilian Hare, and Eiilagos for "i. mediterraneus" and " L. Judcea;.''

In the subdivisions of this A group (Hares), great stress is laid upon a comparatively

unimportant cranial character, which had cautiously been made use of by Baird. Thus

we get two subdivisions : I. Postorbital process more or less united with the skull

[Hydrolagus, Sylvilagtis, Eulagos). J I. Postorbital jirocess separate from the skull

[Lepus, Tapeti).

The species of the genus "■ Lepns" are classed according to geographical distribution,

and thus there are unavoidably throA;!! together very heterogeneous forms in the African,

Asiatic, and American members. Among the latter are L. Audahoiiil and L. Troio-

bridgei, which are thus widely separated from Sylvilagus, containing their closest allies.

The fore-mentioned paper was wasely ignored by J. A. Allen, in his Analysis of the

species and varieties of North American Leporidtef. Allen on the whole follows Baird,

with some im2:)rovements in detail, but with one step backward, by widely separating the

CuUotis group from L. fiinidiis and its allies.

Some of Gray's generic names have since been used as subgenera, e.g. by Mearns,

with whose "Analysis of three Subgenera of Lepus'' %> containing some valuable

information, I propose to deal elsewhere.

A new genus of Leporida^, Romerolagus, from Mount Popocatepetl (3350 metres),

was described some years ago by Hart Merriam §. The author's views as to its

systematic position are summed up in the following words :—" The skull, singularly

enough, does not show the departure from Lepus that one would expect from a

study of the other bones. It agrees in the main with skulls of the American Cotton-

tails (subgenus Sylnilagus), but differs in the postorbital processes, which are small,

divergent posteriorly, and altogether wanting anteriorly, and in the jugal, which is

greatly elongated posteriorly. The interparietal is distinct, and in old age becomes

ankylosed with the supraoccipital. The thoroughly leporine character of the skull shows

that the animal can hardly be regarded as ancestral to Lepus, as might have been

* Ann. & Mag. Xiit. Hist. xx. 3, p. 210 (1807).

t ' Monographs of North American Rodentia. — II. Leporida?,' by J. A. Allen, p. 283 (1876).

+ Proo. U. S. Nat. Mus. xviii. p. 5.51 (1896).

§ Troc. Biol. Soc. of Washington, x. p. 169-174 (1896).

SECOND SEEIES. — ZOOLOGY, VOL. VII. 71

514 DE. C. I. FOESTTH MAJOR 0J\

inferred from its short ears, short hiud legs, and various skeletal characters, hut that it

is a specialized, offshoot from the genus Lepus itself "' *.

My own views as to the significance of the characters of Romerolagus are about the

same as those with regard to Caprolagus. They are certainly of generic value, hy com-

parison with those generally assigned to the genus Lepus. But it does not follow that

Romerolagus can stand as a separate genus, or, to put it in a more general way, that

it occupies an isolated position compared with other Leporidae. I feel sure that if the

same care had been bestowed on the examination of the skeletons of some other Leporidae

near at hand, e. g. the aquatic Hares f, Hart Merriam would have arrived at the same

conclusion as I have. It will probably be possible to show hereafter that Romerolagus is

specialized in some respects, as might be anticipated from its habitat. The remarkable

shortness of the ears is presumably the combined result of inheritance and specialization.

The absence of the tail is certainly an acquired character, as it is in Lagomys. The

comjilete clavicle can scarcely be regarded in the same light ; hut, although I know of no

other member of the Leporida3 having a " complete " clavicle, Romerolagus does not, in

this respect either, occupy such an isolated position as the author seems to think. That

the skull is " thoroughly leporine " I cannot admit ; there are several cranial characters,

as will be shown, which are unusual in most Leporidae, but which Romerolagus shares

with Pahcolagus, with some recent Leporidae, and with the Lagomyidae, and which may

be I'egarded as ancestral.

The whole of recent Leporidae may be divided into two groups, probably of higher

than generic dignity, which might conveniently be called : A. Caprolagus group, and

B. Lepus group.

A. Caprolagus Group : — ■

1. Caprolagus: C. sivalensls, Maj.; C. valdaruei/sis (Weith.) ; C. hispidus

(Pears.) (type.)

2. Nesolagus (nom. nov.) : N. Netscheri (Schleg. & Jent.).

3. Oryctolagus : O. cnnicultis (Linn.) ; O. crassicaudatus (GeoflFr.).

4. Sylvilagns, comprising in this term : —

a. Lhnnolagus (S. pialustris, aqualicus, &c.).

b. Romerolagus (S. Kelson/', iMerr.).

c. Tapetl [S. braslliensis, &c.).

d. Sylcilagus (S. sylvaticus, &c.)

The question whether 1-4 are to be considered as genera or subgenera is for the

present quite immaterial. Sylvilagus s. str. is the least primitive of this group, and

Oryctolagus stands somewhat apart.

B. Lepus Group. — This group contains the one genus Lepus s. str., including all the

species not contained in group A.

* Op. cit. p. 172.

t This remark refers also to the limbs, although I do not know them from either.

FOSSIL AND EECENT LAG03I0EPHA. 515

The Caprolaxjvs group (A) differs from the Lepus group by the following characters,

part of which, as said above, it shares with Paheolagiis aud with the Lagomyida? : —

Lesser specialization for speed, and in correlation with this, lesser develoi^ment of organs

of sense (sight, smell, hearing). Fore and hind feet comparatively short and subequal.

Ears short. Eves smaller. Tail very short or missing.

Cranium, depressed above, anteriorly and posteriorly very little bent downward. Upper

contour of frontals and posterior part of nasals almost horizontal (exc. Orijctolagus).

Inferior border of orbit — formed by malar bone — shorter than in the Lepus group ; sinus

on the lateral face of malar not advancing so far forward (exe. in Oryctolagus). Upper

border of zygoma l)ent inward, inferior Ijorder arched outward (exc. in Oryctolagus).

Posterior appendix of zygoma elongate and, in correlation, mandibular condyloid process

elongate also (exc. in Oryctolagus crassicaudatus) .

Infraorbital foramen larger than in Lepus and its immediate neighbourhood almost

devoid of reticulation. The heavier skull in the X group is in evident correlation with

the different mode of locomotion. The following cranial characters of A are apparently

in correlation with the less develojoed organ of smell : — Horizontal portion of os palatinum

comparatively well develojied ; interpterygoid fossa and choaufe comparatively small.

Foramina incisiva comparatively narrow and short. Anterior part of nasals less inflated

than in Lepus. In correspondence with the smaller eyes, the orbits are comparatively

small, and the orbital processes more or less reduced.

In conclusion, I wish to express my very special obligations to Prof. Howes for loan

of material, valuable suggestions, and the pains he has taken in connection with this

memoir.

EXPLANATION OF THE PLATES.

Plate 36.

Fig. 1. Cnprolayus [Oryctolagus) cunkuhis (Linn.), jiiv. Riglit maxiHary ; cl. 3-m. 2.

Fig. 2. Plemidapis Dmibrei, Lem. Riglit upper molar. Enlarged copy from Bull. Soc. Gcol. France,

3. xix. (1891) pi. X. fig. 62 w.

Fig. 3. Pelycodus helveticus, Riit. Right upper molar. Enlarged copy from Abh. Schweiz. Pal. Ges.

XV. pi. fig. 12 ff (1888).

Fig. 4. Prolaf/us sardits (Wagn.). Left maxilla with deciduous teeth (d. 3-d. 1) and first molar. Monte

San Giovanni (Sardinia). Br. Mus. G. D. No. i\I3464.

Fig. 5. Caprolagus {Oryctolagus) cuniculus (Linn.); slightly older than fig. 1. Right maxilla; d. 3-

m. 2 ; alveolus of m. 3.

Fig. 6. Titunomys Fontannesi (Dep.). Second (last) right upper molar (m. 2), almost disused. Middle

Miocene. La Grive-Saint-Alban (Isere), as all the other specimens of this species *.

Fig. 7. THanomys Fontannesi (Dep.). First right upper molar Cm. 1).

Fig. 8. THanomys Fontannesi (Dep.). Posterior right uj^per premolar (p. 1). Br. Mus. G. D. No. 5268

Fig. 9 THanomys Fontannesi (Dep.) ? Second right upper premolar (p. 2) ? *

Fig. 10. Prolagus ceningensis (Kon.). The three left upper premolars (p. 3-p. 1) of young specimen.

Middle Miocene. La G rive-Saint- Albau, as all the other specimens of this species. Br.

Mus. G. D. No. 5234.

* The figures marked thus are from specimens in the possession of the author.

71*

516 DE. C. I. EOKSTTH MAJOR ON

Fig. 11 Prolagus sardus (Wagn.). Posterior right upper premolar (p. 1), from a young specimen.

Monte San Giovanni (Sardinia). Br. Mus. G. D. No. M3461.

Pi"-. 13. Titammys Fontannesi (Dep.). First left upper molar (ni. 1), slightly worn.

Fig. 13. Titanomys Fontannesi (Dep.). First left upper molar (m. I), slightly worn.

Fig. 14. Titanomys Fontannesi (Dep.) . Right upper, probably deciduous, molar ; mueh worn *.

Fig. 15. Titanomys Fontannesi (Dep.). Posterior right upper premolar (p. 1) *.

Fio-. 16. Prulnyus sardus (Wagn.). Fragment of right maxillary ramus, with posterior premolar (p. 1),

and the two true molars (m. 1, m. 2). Monte San Giovanni. Br. Mus. G. D. No. M3159.

Fi"-. 17. Caprolagus [Oryctolagus) cuniculus (Linn.). Young individual, slightly older than fig. 5. The

two posterior premolars (p. 2, p. 1) and the two anterior molars (m. 1, m. 2) of the right side.

Fio-. 18. Titanomys visenoviensis, H. v. Mey. Upper molar, much worn. Bravard Collection. Lower

Miocene, AUier. Br. Mus. G. D. No. 31094-104.

Fig. 19. Titanomys visenoviensis, II. v. Mey. The two posterior ]n-emolars (p. 2, p. 1), from a fragment

of the right maxillary. Lower Miocene of Wcisenau ((jcrmany). Br. Mus. G. D. No. 21495.

Fig. 20. Caprolagus (Syhilayus) brasiUensis (Linn.). Riglit upper posterior deciduous molar (d. 1), from

a skull in the Br. Mus. Z. D. No. 58.4.15.1.

Fig. 21. Prolayiis (eningensis (Kon.). Complete series of the riglit upper cheek teeth (p. 3-m 2)*.

Fig. 22. Lejjus timidus, Linn. (L. variabilis, Pall.). Right upper cheek-teeth of young individual; the

two posterior deciduous molars have been removed, in order to show the overlying premolars

(p. 2, p. 1). Ireland. W. E. de Wintou, Esq.

Fig. 23. Titanomys Fontannesi (Dep.). Left upper jaw, showing the empty alveoli of the five cheek-

teeth. 4x1*.

Fig. 24. Prolagus sardus (Wagn.). Complete series of the right upper cheek-teeth, or (p. 3-m. 2).

Ossiferous breccia of Monte San Giovanni (Sardinia) *.

Fig. 25. Lepus europceus, Pall. Unworn right upper median premolar (p. 2) of young individual.

From a skull in the Br. Mus. Z. D. No. 523 /.

Fi"^. 26. Lepus timidus, Linn. Posterior right upper deciduous molar (d. 1 ), removed from the jaw fig. 22.

Fio-. 27. Caprolagus hispidvs (Pears.). Median right upper premolar (p. 2), of young individual in the

Br. Mus. Z. D.

Fig. 28. Lepus sp. Right upper deciduous molars (d. 3-d. 1). China. Br. ilus. Z. D.

Fig. 29. Prolagus wningensis (Kiin.). Right upper deciduous molar (either d. 1 ord. 2) *.

Fig. 30. Lagopsis verus (Hens.). Right upper deciduous molar (either d. 1 or d. 2). Middle Miocene

of La G rive-Saint- Alljan *.

Fig. 31. Lagopsis verus (Hens.). Median riglit upper pi-emolar (p. 2). La Grivc-Saint-Alban. Br.

Mus. G. D.

Fig. 32. Lagopsis verus (Hens.). Left upper molar. La Grive-Saint-Alhan. Br. Mus. G. D.

Fig. 33. Cajjrohigus hispidus (Peavs,.). Comjilete series of the right ujiper cheek-teeth. Adult. From

a skull in the Br. Mus. Z. D.

•i^'ig. 34. Lejms nigricollis, F. Cuv. Posterior right upper premolar (p. 3). Br. ]Mus. Z. D. No. 81.4.29.7.

Fig. 35. Titanomys Fontannesi (Dep.). Left upper deciduous molar (either d. 1 or d. 2) *.

Fig. 36. Paheolayus Haydeni, Leid. Fragment of right maxillary ramus, showing the empty alveolus

of the median premolar (p. 2), and the three following cheek-teeth (p. 1, in. 1, m. 2). Br.

Mus. G. D. No. M5727.

Plate 37.

Fig. 1. Titanomys Fontannesi (Dep.). Isolated lower anterior premolar (p. 2), unworn. Middle

Miocene of La Grive-Saint-Alban, like all the other specimens of this species*.

Fig. 2. Titanomys Fontannesi (Dep.). Another isolated specimen of the same tooth, slightly worn*.

FOSSIL AND EECEXT LAGOMOEPHA. 517

Fig. 3. Titunoiiiys Funtmimsi (Dep.). A third isolated specimen of the same, slightly more worn by

attrition than the former *.

Fig. 4. Titunomijs Fontannesi (Dep.). A fourth isolated specimen of the same, much worn *.

Fig. 5. Prolagus sardus (Wagn.), var. corsicanus. The two inferior deciduous molars (d. 2, d. 1) from

a left mandibular ramus. The first true molar (m. 1) of the specimen, not figured, shows a

vestige of the terminal cusp (" t " = hypoconulid).

Fig. 6. Prolagun aiiinc/ensis (Kon.). Left mandibular ramus of young individual, showing the two

deciduous (d. 2, d. ]) and the two true molars (m. 1, m. 2). La Grivc-Saint-Ali)au. Br.

Mus. G. D. No. M523G.

Fig. 7. Titanoinys Fontannesi (Dep.). Complete series of the lower cheek-teeth (p. 2-m. 3) in a left

mandibular ramus. Adult. Br. Mus. G. D. No. 5267 a.

Fig. 8. Caprolagus [Onjctolagus) cuniculvs (Linn.). The two lower premolars (p. 2, p. 1), in a right

mandibular ramus of an immature specimen. Herefordshire. W. E. de Winton, Esq.

Fig. 9. Pro/uf/tis (eninycnsis (Eiin). Complete series of inferior cheek-teeth (p. 2-m. 2), left side.

Adult *.

Fig. 10. Titanomys Fontannesi (Dep.). Posterior premolar (p. 1) and anterior true molars (m. 1, m. 2)

in a left mandibular ramus of an immature specimen, p. 1, being still in the socket, has not

yet come into attrition. Br. Mus. G. D. No. 52G~ b.

Fig. 11 «. Titanonnjs visenoviensis, 11. v. Mej. Isolated upper postei'ior premolar (p. 1), or anterior

molar (m. 1?, right side. Lower Miocene of Weisenau. Br. JIus. G. D. No. 7217 c.

Fig. 11 b. Titanomys visenoviensis, H. v. Mey. Probably posterior premolar (p. 1) or anterior molar

(m. 1). Left side. Lower Miocene of Weisenau. Br. Mus. G. D. No. 7217 d.

Fig. 12. Prolagus wningensis (Kon.). Anterior premolar (p. 2) from a left mandibular ramus.

Fig. 13. Caprolagus Lacosti (Pomel). Anterior premolar (p. 2) from a left mandibular ramus. Upper

Pliocene of Perrier (France). Br. Mus. G. D. No. 27618.

Fig. 14. Lagopsis rents (Hens.). The tAvo posterior true molars (m. 2, m. 3) from a right mandibular

ranms. La Grive-Saint-Alban. Br. Mus. G. D. No. 5263.

Fig. 15. Titanomys Fontannesi (Dep.). Upper view of left mandibular ramus, exhibiting the empty

alveoli of the five cheek-teeth *.

Fig. 16. Titanomys Fontannesi (Dep.). Posterior premolar (p. 1) and the two auteriot true molars

(m. 1, m. 2) in a right mandibular ramus. Empty alveoli of p. 2 and m. 3. Br. Mus. G. D.

No. M5267 c.

Fig. 17. Caprolagus {Nesolagus) Netscheri (Sehleg. & Jent.). Posterior upper premolar (p. 1), right

side, from the skull in the Br. Mus. Z. D. No. 92.5.24.1. Sumatra.

Fig. 18. Caprolagus sivalensis, Maj. The two inferior premolars (p. 2, p. 1), from a fragment of the

left mandibular ramus. Pliocene, Siwalik Hills, India. Cautley Coll. Br. ^lus. G. D.

No. 16529. (By an inadvertence of the artist, the anterior side of the teeth is turned to the

right — their outer side being directed upwards in the plate — instead of to the left, as in all the

other figures of mandibies and teeth of the left side.)

Fig. 19. Caprolagus {Ronterolagus) A\'lsotii (Merr.). Anterior premolar (p. 2), from a right mandibular

ramus. Mount Popocatej)etl (Mexico). Br. Mus. Z. D.

Fig. 20 a, b. Caprolagus {Sylvilagus) palustris (Baehm.). Lower anterior premolars (p. 2), right {a) and

left [b), from a specimen in the Br. Mus. Z. D.

Fig. 21. Titanomys Fontannesi (Dep.). The posterior premolar (p. 1) and the two anterior true molars

(m. 1, m. 2) in a fragment of the right mandibular ramus.

Fig. 22. Caprolagus hispidus (Pears.). The two premolars (p. 2, p. 1) from tiie right mandibular ramus

of an immature specimen in the Br. Mus. Z. D.

Fig. 23. Caprolagus Iiispidu^i (Pears.). Complete series of lower cheek-teeth (p. 2-m. 3) from a rio-ht

mandibular ramus of an adult specimen in the Br. Mus. Z. D.

518 Dl^. C. I. rOESTTH MAJOR ON

Fig. 24. Titanomys visenoviensis, H. v. Mey. The two aBterior true molars (m. 1, ra. 2) from a frag-

ment of the left mandibular ramus. Bravard Coll. Lower Miocene of Allier (France). Br.

Mus. G. D. No. 31095.

Fig. 25. Titanomys visenoviensis, H. v. Mey. The two premolars (p. 2, p. 1), from a fragment of the

right mandibular ramus. Lower Miocene of Allier. Br. Mus. G. D. No. 31096.

Fig. 26. Lagopsis rerns (Hens.). Tlie four anterior cheek-teeth (p. 2, p. 1, m. 1, m. 2) and the empty

alveolus of the last (m. 3)^ in a left mandibular ramus. La Grive-Saint-Alban *.

Plate 38.

Fig. 1. Caprolagus {Sylvilagus), sp., jnn., from Bogota. Right raanus, anterior or upper surface view,

Nat. size. V — vesalianum (carpale V); h — hamatum (carpale TV). Nat. size.

Fig. 2. The same. External (ulnar) view. Nat. size.

Fig. 3. Caprolagus (Oryctulagus) crassicaudatus (Is. Gcofl'r.). Br. Mus. Z. D. No. 96.6.6.L Left

manus, ulnar view. Nat. size.

Fig. 4. Lagomys rvfescens, Gray. Br. Mus. Z. D. Right manus, anterior view. 2x1.

Fig. 5. Caprolagus {Oryctolagus) cuniculus (Linn.), juv. Right tarsus, ulnar view. Nat. size.

Fig. 6. Caprolagvs (Sylvilagus) brasiliensi.i (Linn.), juv. Roy. Coll. Sc., London. Right tarsus, ulnar

view. Nat. size.

Fig. 7. Caprolagus {Sylvilagus) , sp. juv. Bogota. Right tarsus, ulnar view. Nat. size.

Fig. 8. Caprolagus (Sylvilagus) brasilieusis (Linn.), juv. Roy. Coll. Sc, London. Right antebra-

chium and manus. a, anterior, /;, posterior or volar view. Nat. size.

Fig. 9. Lagopsis verus (Hens.), or Titanomys Fo7itannesi (Dep.). Middle Miocene, La Grive-Saitit-Albau.

Br. Mus. G. D. No. M5274. Right metatarsus V. a, anterior; b, posterior view. 2x1.

Fig. 10. Lagopsis verus {Herts. ), or Titanomys Fontannesi {T)q]\.). Middle Miocene, La Grive-Saint-Alban.

Br. Mus. G. D. M 5273. Left ulna, a, anterior ; b, posterior view. Nat. size.

Fig. 11. Prolagus sardus (Wagn.). Left ulna. «, anterior ; 6, posterior view. Nat. size. Pleistocene

breccia, Monte San Giovanni (Sardinia). Br. Mus. G. D. M 3471.

Fig. 12. Prolagussardus {'Wa<^n.). Right radius, a, anterior ; 6, external (ulnar); r, internal (radial) ;

d, posterior View. Nat. size. Pleistocene breccia, Monte San Giovanni (Sardinia). Br. Mus.

G. D. M3471.

Fig. 13. Prolagm sardits (Wagn.). Left metatarsus II, from behind. 3x1. Pleistocene breccia,

Monte San Giovanni (Sardinia). Br. Mus. G. D.

Fig. 14. Lagomys rufescens, Gray. Left metatarsus II, external (fibular) view. 3x1. Br. Mus. Z. D.

No. 74.11.21.17.

Fig. 15. The same. Posterior view. 3x1.

Fig. 16. The same. Anterior view. 3x1.

Fig. 17. Prolagus cmingensis (Kon.). Left metatarsus II, anterior view. 3x1. Middle Miocene,

La Grive-Saint-Alban. Br. Mus. G. D. No. M5248.

Fig. 18. The same. External (fibular) view.

Fig. 19. Prolagus sardus (Wagn.) . Right metacarpal V, from the outer (ulnar) side, to show the facet for

the OS vesalianum (carpale V). 5x1. Pleistocene breccia, Monte San Giovanni (Sardinia),

Br. Mus. No. G. D. No. M3471.

Fig. 20. Lagomys rufescens, Gray jnn. Right antebrachium. «, front view; 6, external (ulnar) ; c, internal

(radial) view. 2x1. Br. Mus. Z. D.

Fig. 21. Lagomys rufescens, ad. Right radius, a, internal (radial) ; b, front view. 2x1. Khorassan.

Col. Yate.

Fig. 22. Caprolagus (Oryctolagus) crassicaudatus (Is. Gcofl'r.). Left tarsus and metatarsus; internal

(tibial) view. Nat. size. From skel. Br. Mus. Z. D. No. 96.6.6.1.

FOSSIL AND EECENT LAGOMOEPHA. 519

Fig. 23. Caprohiyus {Nesulayus) Netscheri (Scbleg. & Jent.). Right tarsus and metatarsus ; internal

(tibial) view. Nat. size. From skel. Br. Mus. Z. D.f

Fig. 24. Caprolagus {Caprolagus) fiispidus (Pears.). Right tarsus and metatarsus, internal (tibial) view.

Nat. size. Br. Mus. Z. D.

Fig. 25. Lepus timidus, Linn. {L. varuihUis, Pall.). Right tarsus and metatarsus, internal (tibial) view.

Nat. size. Ireland. Br. Mus. Z. D. No. 76.4.10.2.

Fig. 26. Lnyomys rufescens, Gray. Right tarsus and metatarsus, internal (tibial view). 2x1.

Fig. 27. Prolagus sardus (Wagn.), var. corsicanvs. Left metatarsus II. a, antei'ior; b, internal;

c, posterior ; rZ, external view. Nat. size. Pleistocene breccia, Toga nr. Bastia (Corsica). Br.

Mus. G. No. D. M 3486.

Fig. 28. Caprolagus {Nesolagus) Netscheri {^c\i\eg.k, Jcut.). Left autebrachium. «, front view; J, ex-

ternal (ulnar) ; c, internal (radial) ; d, posterior view. Nat. size. Sumatra. Br. I\Ius. Z. S.

Sumatra. Br. Mus. Z. D.

Fig. 29. Logomys rufescens, Gray. Riglit nlna. a, external (ulnar) view (almost posterior in adult

Leporidae) ; b, posterior view (almost internal in adult Leporidte) ; c, front view (almost

extei-nal in adult Leporida;). 2x1. Khorassan. Col. Yate.

Fig. 30. Caprolagus {Orijclolagiis) canicii/iis (Linn.). Left antebrachium. a, front; b, external (ulnar);

c, internal (radial) ; d, posterior view. Nat. size. Herefordsliire.

Plate 39

Fig. 1. Titunoiuys Fontannesi (Dep.). m. 1, sup. dext. Anterior view. 3x1. Middle Miocene. La

Grive-Saint-Alban *.

Fig. 2. Titanomys Fontannesi (J)e^.). m. 2, sup. dext. «, anterior; 6, external view. 3x1. La Grive-

Saint-Alban *.

Fig. 3. Sciaropterus fuscocapiUus, Blyth. m. 2, sup. dext. Anterior view. 4x1. Br. Mus. Z. D.

No. 52.5.9.19.

Fig. 4. Titanomys Fontayinesi (Dep.). Upper deciduous molar, much worn. Anterior view. 3x1.

Tooth figured PI. 36. fig. 14.

Fig. 5. Titanomys visenoviensis, a. V. ^iej. p. 2, sup. sin. «, posterior; Zi, lower view. 4x1. Lower

Miocene, Weisenau. Br. Mus. G. D. No. M7217.

Fig. 6. Titanomys Fontannesi (J) e^.). Right lower molar, a, anterior ; 6, inner ; c, outer view. 21x1.

La Grive-Saint-Albau *.

Fig. 7. Caprolagus (^Oryclohigus) cuniculus (Linn.), juv. m. 1, sup. sin., posterior view. 3x1.

Fig. 8. Caprolagus (Oryctolagtis) cuniculus (Linn.), juv. m. 1, sup. dext. Anterior view. 5x1.

Specimen figured PI. 36. fig. 1.

Fig. 9. Capi'olagus (Oryctolagus) cuniculus (Linn.), juv. dec. 1, sup. dext. a, anterior; b, outer view.

5x1. Specimen figured PI. 36. fig. 1.

Fig. 10. Pterornys melanotis, Gray. m. 2, sup. dext. Anterior view. 3x1. Br. Mus. Z. D.

No. 48.8.15.2.

Fig. 11. Titanomys visenoviensis, H. v. Mey. Left lower molar. «, outer; 6, inner; c, anterior view.

2i x 1 Br. Mus. G. D. No. 21495.

Fig. 12. Titanomys Fontannesi (Dep.)? p. 2 sup. dext. (?) Anterior view. 4x1. La Grive-Saint-

Alban. Specimen figured PI. 36. fig. 9. After renewed examination, the generic affinities of

this tooth seem very doubtful.

t pc. of this fig. to be read together {=pc. prsecuneiform).

620 POSSIL AND EECENT LAGOMORPHA.

Fig. 13. Titanomys Fontannesi (De^.). m. 1 s-up. sin. Anterior view. 3x1. La, Grive-Saint-Alban.

Specimen figured PI. 36. fig. 12.

Fig. 14. Titanomi/s visi'noviensis, K. V. Mej. m. sup. dext. Anterior Wew. 3x1. Specimen figured

PI. 36. fig. 18.

Fig. 15. Smiropi(Tusi xanthipes (Milne-Edw.) . m. 2, sup. dext. Anterior view. 3x1. Ur. Mn.s. Z. D.

No. 95.7.5.1.

Fig. 10. TUanomys visenoviensis, H. v. Mey. m. 2 sup. dext. Lower view. 10 x 1. Weisenau. Br.

Mus. G. D. No. M7217.

Fig. 17. Caprolai/us [Sylvilagus) brasiliensis (Linn.), jun. Sternum. Front view. Nat. size. Royal

College of Science, London.

Fig. 18. Cajyrulayus (Nesulaffus) Neischeri (Sclileg. & Jent.). Sternum. Front view. Nat. size. Br.

Mus. Z. D. '

Fig. 19. Titanomys Fontannesi (De]).). p. 1 sup. dext. Anterior view. 3x1. Specimen figured PI. 36.

fig. 8.

Fig. 20. Pteromys nitidus, Desm. Germ of m. 2, sup. dext. Anterior view. 3x1.

Fie-. 21. Titanomys Fontannesi (Dep.). dec. sup. sin. Anterior view. 3x1. Specimen figured

PI. 36. fig. 35.

Fig. 22. Lugopsis verus (Hens.), dec. sup. dext. Anterior view. 4x1. Specimen figured PI. 36.

fig. 30.

Fig. 23. Prolagus oeninffensis (Kbn.). dec. sup. dext. Anterior view. 7x1. La Grive-Saint-Albau.

Specimen figured PI. 36. fig. 29.

Fig. 24. PToJagvs sardiis (Wagn.), var. corsicmins. IMetatarsns IL Pleistocene breccia of Toga, near

Bastia (Corsica). 3x1.

Fig. 25. TitanomyK Fontannesi (Dep.). Left mandibular ramus, a, inner; (!», outer view. Nat. size.

La Grive-Saint-Alban *.

Fig. 26. Prolagus osni7ige?isis (K'6n.). dec. 2 inf. 4x1. La Grive-Saint-Alban *.

Fig. 27. Prolagus sardus (Wagn.), var. corsicanus. Right mandibular ramus.' a, inner; h, outer view.

Nat. size. Pleistocene breccia, Toga (Corsica) *.

Fig. 28. Caprolagus (Nesolagus) Neischeri (Schleg. & Jent.). Right mandibular ramus, outer view.

Nat. size. Br. Mus. Z. D. No. 92.5.24.1.

Fig. 29. Titano7nys Fontannesi (Dep.). Posterior fragment of right mandibular ramus, a, outer; 6, inner

view. Nat. size. La Grive-Saint-Alban *.

Fig. 30. Lagopsis varus (Hens.). Right mandibular ramus, a, outer; A, inner view. Nat. size. La

Grive-Saint-Alban *.

Fig. 31. Titanomys Fontannesi (Dep.). Left mandibular ramus, a, outer; 6, inner view, Nat. size.

La Grive-Saint-Alban *.

Fig. 32. Caprolagus [Caprolagus] Mspidus (Pears.). Palatal view of skull. Nat. size. Br. Mus.

Z. D. No. 48.9.12.11. »j = maxillary, 7J = palatinum.

Fig. 33. Caprolagus {Sylvilagus) Nelsoni (Merr.) [Ruuierolagtis Nelsoni, Men:]. Palatal view of skull.

Nat. size. Popocatepetl, Mexico. Br. Mus. Z. D. No. 97.6.1.5.

Fig. 34. Lagomys rvfescens, Gray. Palatal view of skull. Nat. size. Br. Mus. Z. D.

Fig. 35. Cnprolayus (Sylvilagns) brasiliensis (Linn.), juv. Palatal view of skull. Nat. size. Royal

College of Science, London.

Fig. 36. Prolagus sardus (Wn^n.). Palatal view of skull. Nat. size. Pleistocene breccia, Monte San

Giovanni (Sardinia). Br. Mus. G. D.

Fig. 37. Co]jrolagvs [Oryctolagus] crassicaudatus (Is. Geofii'.). Palatal view of skull. Nat. size. Br.

Mus. Z. D. No. 96.6.6.1.

Fig. 38. Caprolagus {Nesolagus) Netscheri (Schleg. & Jent.). Palatal view of skull. Nat. size. Br

Mus. Z. D.

FORSV rH M A.IOR.

Traxs. Linn Soc. Ser. 2, Zool. Vol. vii. PI. 36.

/. Griinvi.ld, del.

•FOSSIL AND RECENT LAGO.MO RPH ,A.

Collo. bv Mvis^uH &■ Kiiid.

F O K S Y T H .M A J O K.

"rans. Lin\ Sue. SiiK. 2, ZooL. Vol. vii. 1^1. 37.

H. GrunvoUi, del.

V

J •!-■

FOSSIL AND RECENT LAGOMORPHA.

Collo. by Moigan & Kidd

F O K S V T H M A J O R.

Titans. Lin.n Scjc. Zool. Sek. 2, \'iil. vii. PI. 3S.

H. Gioni-oU, dtl.

FOSSIL AND RECENT LAGOMORPHA.

Collo. by Mov^an e- Kitid.

Forsyth Major.

Trans. Linn Soc. Zool. Ser. 2, Vol. vii. PI. 39.

;/. Gromvld, ilel.

Collo. by Morgan tS- KidJ.

FOSSIL AND RECENT L.AGO M O R P H A.

LINNEAN SOCIETY OF LONDON.

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2nd Ser. ZOOLOGY.]

AUG 10 1900

[VOL. VII. PART 10.

THE

TTiANSACTIO^TS

OF

THE LINNEAN SOCIETY OF LONDON.

ON THE GENUS LEMNALIA, Gray;

WITH AN ACCOUNT OF THE BRANCHING-SYSTEMS OF THE

ORDER ALCYONACEA.

BY

GILBERT C. BOURNE, M.A., F.L.S.,

FELLOW AND TUTOR OF NEW COLLEGE, OXFOUU ; UMVEKSITY LECTURER IN COMPARATIVE ANATOmr.

"L O N I) O N :

PRINTED FOR THE LIXNEAX SOCIETY

BV lAVr.Olt AMU FRANCIS, KKI) LION COIJIIT, FLEET STREET.

SOLD AT THE SOCIETV's APARTMENTS, BURLINGTON-HOUSE. PICCADILLY, W.,

AND BY LONGMANS, GREEN, AND CO., PATEENOSTER-EOW.

March 1900.

[ 521 ]

X. Oti the Genus Lcmnalia, Gray ; icith an Account of the Brunchiny-systems of the

Order Alcyonacea. By Gilbert C. Bourne, M.A., F.L.S., Fellow and 'Tutor of

New College, Oxford ; University Lecturer in Comparative Anatomy .

(Plates 40-42.)

Read 16tli Febniarv, 1899.

In the course of a description of the Anatomy of Alcyonium digitaium, Hickson * lias

called attention to the unsatisfactory and misleading terms employed in the descrip-

tion of Alcyonarian polyps and colonies. It is the fact that, ^^ liile Allman and Haeckel

have provided us with a set of precise terms descriptive of the component parts of the

Hydrozoa, the terminology of the Anthozoa remains in a state of the utmost confusion.

For cxam2ilo, the name " polyp " is applied sometimes to the whole Alcyonarian zooid or

individual, sometimes only to that j^in't of it, whether retractile or non-retractile, which

emerges from the surface of a colony. The name " coenenchyme " is applied to any mass

of tissue in which the zooids are imbedded, no distinction being made between the

various modes in which zooids may be aggregated together to form a mass or colony.

The name " stolon " is used to denote the root-like basal outgrowths by which the

Cornulariidce are attached to foreign objects, and also the canals lined by endoderm

which place the cavities of the zooids composing a colony in communication, and form

so large a part of the so-called coenenchyme of colonial Alcyonarians. It is unnecessary

to give further examples ; these few will suffice as a justification for my burdening

zoological literatvire with a new set of descriptive terms. I do not, however, propose to

suggest a complete set of terms for the whole of the Alcyonaria in this paper, but to

confine myself to the Oi'der Alcyonacea. Some of the terms projiosed are applicable only

to the members of this order, others are applicable to all Alcyonarian zooids. In the

first place I wish to substitute the name " cwo«rf " for that of " j}oli/p" f. The name

zooid is applicable to any asexually-produced individual entering into the composition

of a colony, and therefore Kolliker was in ei-ror when he restricted it to those

arrested and modified individuals whose function it is to drive currents of water through

Alcyonarian colonies. These should be called siphonozooids. Tliereare, of course, many

kinds of zooids, since there are many groups in the animal kingdom in which asexually-

produced individuals are united to form colonies, and these may be distinguished as

* S. J. Hickson, "The Anatomy of Alcymiium diijitdium,''' Quart. .Journ. Mier. Sci., new ser., vol. xxxviii.

p. 354.

t See Moseley, 'Challenger' Reports, Zoology, vol. ii. p. 118, and Milnes-Marshall, Trans. Roy. Soc. Ediuburgh,

xxxiii. 1888, p. 453.

SECOND SERIES. — ZOOLOGY, ""^OL. VII. 72

522

ME. G. C. BOUENE ON THE GENUS LEMNALIA AND

hydrozooids, anthozooids, i^oly- or hryozoolds, ascidiozooids, and so forth. The name

zooid is to he preferred to that of polyp, hecanse it is so easily compounded with other

names for descriptive purposes.

The Oi'dcr Alcyonacea comprises those Alcyouarian colonies whose component zooids

are elongate and united proximally hy fusion of the ectoderm [Xenia) or mesoglcea (all

other Alcyonacea) of their adjacent walls so as to form a bunch. Such a hunch may

conveniently be described as an anthodete, from the Greek Serij, a fagot. In the

simplest forms of the Alcyonacea, the Xeniida, the anthodete may be compared to a

bunch of flowers, all simple scapes, the lower moieties of whose peduncles have been

fused together, the upper moieties and flowers remaining free. In this case it is obvious

that the cavity of every zooid in the bunch extends down to the base of the colony ; and

the analogy of the bimch of flowers would be complete if it were imagined that all the

peduncles were hollow and that their cavities were put into communication, in the

region where they ai'e fused together, by numerous short anastomosing canals passing

from peduncle to peduncle. As it is obviously convenient to have names Avhich shall

Fie

Diagnini of a Xeniid colon}-. — The so-called coeiienchvmc is rciireseiited by shading, the free portions of the zooids

and their cavities black, ap.. Apodete ; sd., syndete : «., anthocodia ; as., an anthostele. In this and the

similar diagrams on the following pages the solenia are omitted.

distinguish that part of the anthodete where the zooids are fused together from the part

whfere they are separate, I propose to call the former the syndete {ovv, Sen)), and the

latter the apodete. The anastomosing canals lined by endoderm which place the zooid

cavities in communication have been variously named " stolons," " nutritive-canals,"

" coenenchymal tubes," and so on. I propose to call them solenia, from the Greek

(T^Xi'/i'ioi-, a little pipe or conduit.

The names syndete and apodete refer to the zooids collectively ; but as each zooid

consists of a distal free portion, bearing the mouth and tentacles, and a proximal portion

fused to its neighbours, it will be convenient to call the former the anthocodia (from the

Greek Kul'ia, a flower-head), and the latter the anthostele (from ariiXx], a column). In

THE BEANCHING-SYSTEMS OF THE ALCYONACEA.

523

the XenlidcB the anthocodife are not retractile, but in the Alcyonidce the anthocodia is

introversible within the distal part of the anthostele. It shoukl be borne in mind that

"retractility " in Alcyonarians properly means the introversion of the anthocodia within

the anthostele. The latter is often strengthened at its distal end with spicules arranged

en chevron to form a crown of eight points, usually called the calyx or verruca. It will

be better to call it the anthocrypt. The anthocrypts are rudimentary in the Alcyomd(B,

but are well developed in other orders of the Alcyonaria, e. g. the Gorgonidce. As will

be more particu.larly described in the latter part of this paper, some Alcyonarian zooids

whicli have been described as " retractile " or " j)artially retractile " by various authors

are not introversible, but simply have the power of folding over or withdrawing the

tentacles into the oral disc. In such cases the bases of the tentacles are usually protected

by a special development of spicules, which may either be disposed en chevron (as in.

Siphoiiogorgia among the Alcyonacea), or developed into large shield-like plates as in

Prlmnoa. Such spicular defences are sometimes called calices, sometimes opercula ; it

may be useful to give them a special name, anthopoma, from xw«a, a lid.

Fig. 2.

Diagram of an Alcyonid colony in wliieh five chief members are represented as branching in one plane. — The

branching-system of each chief member may be described as a corymb ; but in the diagram, which is

much simplified, the anthocodi;B of the two outside members do not lie in the same plane. They may be

said, however, to bo corymbs, if the surface of the syudete is regarded as the plane to which all the

branches attain. 1,1. Anthocodia! of the chief zooids.

The family Alct/onidce differs from the Xeniidce chiefly in the following respects : — The

anthosteles of the zooids are very intimately united by fusion of their mesogloeal walls ;

only a few of them reach to the base of the colony, the xuajority ending at various

depths in the thickness of the syndete in solenia which put them into communication

with adjacent anthosteles. Returning to the analogy of a bunch of flowers, we may

compare the Alcyonid anthodete to a bunch of corymbs, in wliich not only the main

axes, but also the proximal parts of the secondary, tertiary, and other axes, are fvised

together ; scarcely more than the flowers with very short lengths of peduncle remaining

free. If we imagine, as before, that all the axes are hollow and communicate one with

72*

524 ME. G. C. BOUENB ON THE GENUS LEMNALIA AND

the other by a network of tubular solenia, we have a fairly good idea of the composition

of the Alcyonid anthodete. It must be borne in mind, however, that the anthosteles

corresponding to the secondary axes of a corymb do not open directly into the cavity of

the primary axis, but into solenia grooving out from it. The same is the case with the

tertiary and other axes which open into tbe secondary axes, through the intervention

of solenia.

In the Alcyonid(B the colonies are comparatively simple in shape — mushroom-shaped,

as in Saroophyton ; lobate or bluntly digitate, as in Alcyonium ; none of them branch to

any great extent. In forms like Sarcophytou the apodete is confined to the distal

svu-face of the anthodete, the latter being swollen in this region to form the"pileus,"

while the syndete forms a stem. But in Alcyonium and its allies the apodete occupies

nearly the whole surface of the anthodete, being absent only over a very restricted area

at its basal end. This is the result of the mode of aggregation and budding of the

zooids, the anthocoditc standing out all over the surface of the anthodete. In the

Nephtliyidce, on the other hand, the anthodete is variously ramified, and the anthocodiye

emerge only on the terminal branches and twigs, where they form clusters. Thus the

syndete may be described as forming a barren stem and In-anches composed of the adnate

anthosteles of a certain number of tlu^ zooids forming the colony ; the apodete is

confined to the terminal twigs. Wright and Studer * have described the zooid-cavities,

i. e. the anthosteles, of the Ncplithi/hhc as narrowing below, and ending each in a cnl-de-

snc, but comnmnicating by means of solenia with wide canals, which run in the stem

and larger branches ; these wide canals they called stem-canals or branch-canals. But

KoUiker f long since pointed out that in Siphonogonjia Godeffroyi the stem-canals contain

prolongations of the mesenteries of the zooids, and are, in fact, the extremely long

anthosteles of the primary zooids of tlie colony ; and the case is not different in other

members oi\X\Q jSepldhyidce. I have examined different species of ^mwo/Zjew, Sponyodes,

Lemnalia, and Sipho)togorgia, and find that in each the so-called stem-canals are

nothing more than the extremely long anthosteles of the primary zooids, and contain

prolongations of the asulcar mesenteries, sometimes also of the remaining six mesen-

teries. It is true that most of the anthosteles in a Nephthyid colony do thin out and end

blindlv as described by Wright and Studer, but these belong to the secondary, tertiary,

and other zooids which spring from the solenia given off by the primary zooids. The

continitity of a stem-canal with a zooid-cavity can be determined only by the patient

study of long series of sections.

Perhaps the difference betAveen the Alcyonidce and the Nephthyidce may be best

understood if the anthodete of the latter is regarded as a bundle, not of corymbs, but of

compound racemes whose main axes are of very various lengths. Let us imagine a

number of racemes a, h, c, d (tig. 3), whose secondary and tertiary axes are long,

parallel to and fused with the priuiary axis. The proximal parts of all the racemes are

* ' Challenger ' Ecports, Zoology, vol. xssi., Alcyonaria, 1889.

t A. von Kiillikcr, ' Festschrift zur Feier des ;i.5-jahrigen Bestehens d. phys.-med. GeseUschaft in Wiirzburg,'

1874, p. 18.

THE BRANCHING -SYSTEMS OF THE ALCYONACEA.

525

fused into a single bundle for a considerable length, but eventually first one and then

another raceme emerges from the bundle as a branch, and by continued subdivision of

their axes and the emergence of bundles of these as secondary and tertiary branches a

ramifying system is formed, the ultimate axes finally emerging on the twigs as the

anthocodiae of the zooids.

a.b. c.d.

Diagram of the brauchiiig-systeni of a Nephlhyid. — The authodete is represunted as consisting of four chief members

a, b, c, d, each of which branches in one plane on tlie racemose system. The anthosteles of the lateral

members run parallel to those of the chief members, and aie organically fused with them and with each other

throughout the greater part of their length, a', 6', c', rf'. Terminal anthocodiic of the chief members.

a'. Terminal anthooodia of a lateral member of the second order. «■", a*. Anthocodi* of third and fourth

orders. It should bo noted that the branching-system of the anthodete as a whole, which in this case is a

dichotomy, does not corresi)oud with that of its component members.

In this case the primary axis is represented as growing at a rate equal to the secondary

and other axes, but there are cases in which the primary axis is arrested in growth and

the other axes grow past it and alone pass into tlie branches. In other words, the

primary zooids may undergo cymose subdivision, and in this ease their anthocodiiB

degenerate and the apodete is formed only by the secondary or lower orders of zooids.

None the less the longitudinal canals of the stem and large branches are the anthosteles

of the primary zooids.

The racemose mode of subdivision of the primary zooids is well illustrated in the genus

Iismnalia, Gray, a member of the family Nephthyidcs and the subfamily Slphonogorghics.

The specimen figured in PI. 40. fig. 4 formed part of a collection of Anthozoa collected by

the late Dr. Gulliver at Zanzibar, and presented by him to the Oxford University Museum.

It is clearly identical with Verrill's AmmotUea nitida *, also from Zanzibar, but it does

• Bull. Mus. Comp. Zool. Harvard, vol. i. 1864, p. 39.

526 ME. G. C. BOUEiSrE OA' THE GENUS LEMNALIA AND

not belong to the genus Ammothea, for the presence of a close feltwork of spicules in the

partitions between the anthosteles of the stem and branches show it to be a member of

the subfamily Sipho)iogorgince as defined by Wright and Stiider.

The genus Lemnalia was described by Gray in the following terms * : —

" Coral soft, fleshy, formed of numerous clustered small cylindrical tubes ; the outer

surface is smooth, destitute of any appearance of spicules, but showing by grooves the

union of the diflFerent tubes that form the mass, each tube ending in a polype. The base

is broad and expanded horizontally, fleshy like the coral, throwing iip several stems which

are irregularly branched, the lateral branches being somewhat two-rowed, the terminal

branches ratlier clustered, each branchlet ending in a cylindrical polype, the mouth and

tentacles of which are completely retractile, only leaving a central knob surrounded by

eight slightly depressed radiating grooves, and entirely destitute of any appearance of

superficial spicules. The whole coral is flaccid, and the larger branches appear to be

more or less compressed, but this may in great part depend on the state of the specimens."

A small woodcut, which faithfully represents the general habit of the type species,

accompanies Gray's description. He included in the genus the type species Lemnalia

Jukesii, L. termmalis= Alcyonum terminale, Quoy & Gaimard, and L. uitida=Ammothea

nitida, Verrill.

Verrill t immediately objected to his species being placed in the genus Lemnalia as

defined by Gray, pointing out that his Ammothea nilida, tbough it appeared smooth to

the naked eye, was seen under the microscope to be filled with numerous slender closely-

interlaced spicules ; that similar spicules, "25 to '5 mm. long by '02 to "025 mm. thick,

occurred in t)ie interior of the stem, and that the " verruca? " {i. e. the anthocodiaj) w' ere

covered with small stout wai'ty spicules "075 to "125 mm. long by "05 to '075 mm. thick.

I can add tliis further objection, that the tentacles are not retractile in any species of

Lemnalia, but arc simply infolded over the oral disc. In fact, Gray's diagnosis was

utterly wrong in several important particulars, and it was only by chance that I examined

the type species in the British Museum and saw that it was closely related to the

specimen which I had already identified with Verrill's Ammothea nitida. But Verrill

was equally beside the mark when he compared liis species with Savigny's figures of

Ammothea virescens [ = 'Nephthya Cordieri, Audouin, Explic. PI. Sav.). There is no likeness

whatever between Saviguy's figures and Lemnalia nitida, but there is, on the other hand,

a very close resemblance between Quoy & Gaimard's J figures of Alcyonum terminale and

Gray's Lemnalia, and the latter author was undoul^tedly right in jilacing this species in

his new genus. I have found a S2:)ecimen in the British Museum which appears to be

identical with it. A sj)ecies described as Alcyonum ramosum is figured in the same place

by Quoy it Gaimard. In habit it resembles Ammothea virescens, Savigny, but the figures

of the anthocodife, which are pedicelled, with rounded heads and infolded tentacles,

recall those of Lemnalia. The position of this species must remain doubtful for the

present. There are four species of Lemnalia in the British Museum — viz., the type

* Ann. & Mag. Nat. Hist. 18GS, ii. p. 442.

t American Journal of Science & Arts, 2nd ser. xlvii. 1869, p. 282.

X ' Voyage de TAstrolabe,' Zool. iv. p. 282, pi. sxiii. figs. 1.5-17.

THE BRANCHING-SYSTEMS OF THE ALCYONACEA. 527

species L. Jukesii; a second seems to be identical with Quoy & Gaimard's Alcyonum

terminale ; the two others are unnamed.

I have been unable to find any reference to Gray's genus subsequent to the paper of

Yerrill's quoted above. It does not ajipear in the ' Challenger' report on the Alcyonaria,

although one of the species in tlie British Museum comes from the 'Challenger' collection.

The five sj^ecimens which I have examined clearly constitute a distinct genus ; and I

have thought it best to retain Gray's name Lemnalia, in spite of the inaccuracy of his

diagnosis, and to rewrite the descriptions of the genus and species as follows : —

Lemnalia, Gray, emend. Bourne.

Colony an upright fixed authodete; the syndete divisible into a stout, barren, smooth

stem, from the top of which a few branches, also smooth, are given ofi'; these, alter a

short course, divide, and the tertiary branches thus formed subdivide into terminal twigs,

on which the anthocodise emerge. The main stem, branches, and l)ranchlets composed of

elongate longitudinally-disposed anthosteles, the more superficial of which appear as

longitudinal ribs on the surface. The anthoeodise may be shortly pedicellate or subsessile;

their arrangement on a branchlet may be either spicate or racemose. Spicules minute,

usually of three kinds: — 1. Elongate fusiform, with more or less prominent warty

projections; found in all j)arts of the authodete, except at the extremities of the tentacles,

and interlaced in an irregular manner to form a feltwork, specially abundant in the

partitions between the anthosteles of the stem. 2. Modified double four-rayed stars,

confined to the outer wall of the stem, each star sending a prolongation of one ray inward.

3. Scale-like or flattened branched spicules exhibiting a fine sculpture on their surfaces,

confined to the distal parts of the tentacles and their pinnules. The anthocodiae not

retractile, but the tentacles can be tightly folded over the wide oral disc, their bases

thickly beset with sj)icula, forming by their apposition a rudimentary anthopoma. The

oral disc spacious, cup-like ; the mouth, generally narrow, leads into a stomodseum, wide

and nearly circular in section in its upj^er moiety, tapering below to form a narrow,

compressed, richly ciliated tube. The zooids so oriented that their sulcar (ventral)

aspects are abaxial, their asulcar (dorsal) aspects axial.

In all the species of Lemnalia the stem and branches look smooth to the naked eye,

but the feltwork of interlacing spicules becomes apparent on microscopical examination.

The partitions between the anthosteles of the stem and main branches ai'e not thick, but

are densely packed with spicules of the elongate fusiform kind, thus defining the position

of Lemnalia among the Siphoiiogorgince. The genus appears to form a link between

SiiiJionogorgia and Ammothea, apj)roaching the former in habit and in the development

of spicules in the partition- walls of the stem, and the latter in the small size and relative

unimportance of its spicules.

The five species which I have examined fall naturally into two groups : (A) those in

wdiich the anthoeodise are subsessile and borne in spikes on the branchlets ; (B) those

528 ME. G. C. BOUENE ON THE GENUS LEMNALIA AND

in which tlie anthocodise are pedicelled and borne at irregular intervals on the branchlets

so as to form a raceme. They may be described as follows .- —

A. AnthocodicB suhsessile, arranged in spikes.

1. Lemnalia Jukesii, Gray. (PI. 40. fig. 1 ; PI. 41. figs. 7, 12.)

Lemnalia Jukesii, Gray, Ann. & Mag. Nat. Hist. 1868, ii. p. 442.

Anthodet^ a broad and short stem fixed by an expanded base ; the stem divides into

several thick branches, from wliich the branchlets bearing anthocodia? ai'e given off.

Both stem and main branches devoid of apodeta?, marked by longitudinal ribs representing

the superficial anthosteles. Usually a terminal anthocodia on each branchlet, below

which the other anthocodise are arranged in obscure double rows. Anthocodise prominent,

of equal diameter to the anthosteles from which they spring. Spicules on the tentacles

and pinnules flattened or slightly rounded, scale-like, clavate, or irregular, w'ith finely-

sculptured surfaces ; measuring from '02 to "1 mm. in length (fig. 12). Spicules of the rest

of the anthodete of one kind : elongate, fusiform, with few inconspicuous w^arty pro-

jections, interlaced in an open feltwork on stem and branches, arranged somewhat

en chevron at the bases of the tentacles, wdiere they form a rudimentary anthopoma,

when the tentacles are infolded, approaching the condition in Siijlionogorgia. Length

of fusiform spicules "4 to '1.5 mm.; breadth about •01.5 mm. Colovu' in spirit: — Stem

and branches light brown, tentacles deep brown, the colour of tlie latter partly due to

their peculiar spicules. Diameter of anthocodia; with infolded tentacles about -6 mm.

Habitat unknown.

Gray's figure gives a very fairly accurate representation of the general habit of this

species. It is readily distinguished from others by its brown colour deepening to dark

brown on the tentacles, and by the fact that the spicules of the stem and branches are

all of one kind and more loosely interlaced tlian in other species.

2. Lemnalta ehabdota, sp. nov. (PI. 40. fig. 2 ; PL 41. figs. 8, 13.)

Stem of the anthodete narrowest at the base, widening gradually upward and dividing

at about half the height of the whole anthodete into three stout bi'anches, whicli

almost immediately subdivide into secondary branches bearing a few short branchlets.

Anthocodiae suhsessile, not projecting far from the surface of the branch, distributed over

the secondary bi-anches and their branchlets in somewhat alternate rows, closely

approximated at the distal ends of the branches and branchlets, more widely separated

in their proximal parts. The branches and branchlets incurved towards the centre of the

anthodete, their tips stout, bkmtly digitiform, each ending in a terminal anthocodia

larger than the lateral anthocodise. Average diameter of the distal ends of the branches

1"75 to 2"0 mm. Average diameter of a terminal anthocodia "75 mm. ; of the lateral

anthocodise '5 to "6 mm. Spicules of the stem of two kinds: — 1. Elongate fusiform,

varying m length from "25 to "75 mm., and in diameter from "035 to "025 mm., covered

with more or less prominent warty spines, which tend to fuse together towards the middle

of the spicule to form two or more collar-like thickenings (fig. 8 a). 2. Irregular spicules

derived from four-rayed double stars, one ray of each star produced into a long spinous

THE BEANCHING-SYSTEMS OE THE ALCYONACEA. 529'

process pointing towards the axis of the anthodete. Average length of a double star,

measured from the tips of the elongated rays, 13 mm.; average thickness aci'oss the centre,

•03 to -04. mm. (fig. 13). Spicules of the tentacles irregular, flattened scales of various

form, generally elongated and hilobed at the two extremities ; their surfaces finely

sculptured ; length from '09 to "04 mm., width from '03 to Ol mm. Colour in spirit,

yellowish white; tentacles brown, llaljitat unknown. A single specimen in the British

Museum of Natural Histoiy, ^n-esented by J. B. Jukes, Esq.

This species, thougli closely allied to, is sufiiciently distinct from the following, from

which it differs in habit, in the size of the branches acd anthocodiic, and in the details

of the spicules.

3. Lemnalia peristyi.a, sp. nov. (PI. 40. fig. 3; PI. 41. figs. •), 14.)

Stem stout, tapering slightly towards the base, dividing at difierent levels into four or

five branches, which pursue a vertical course for some distance before dividing into

terminal branches and branchlets bearing anthocodiie. The terminal branches and

branchlets lax and more closely crowded than in L. rhahdota. Anthocodite subsessile,

not projecting far from the surfiice of the branch, set rather close together on the

branchlets, with a tendency to form whorls. A terminal anthucodia to each branchlet, as

in L, rhahdota. Average diameter of the terminal anthocodia3 '75 mm. ; of the lateral

anthocodite "5 mm. ; diameter of the branchlets about 1"5 mm. Spicules of the stem and

branches of two kinds: — 1. Elongate fusiform, with scattered, slightly })rojecting warts;

lenrfth 5 to '6 mm. ; width "02 to "03 mm. 2. Modified double stars of the same oneneral

character as in L. rhahdota, but smaller, more slender, and AA'ith longer projecting rays ;

average length, measured from the tips of the elongated rays, -12 mm. ; average thickness

•02 mm. The tentacles have relatively few flat sculptured scales like those of L. rhahdota,

their place being taken by small fusiform spicules, furnished with two whorls of four rather

prominent spinous rays ; length of these spicules about '035 mm., breadth about -005 mm.,

distance from end to end of oi)posite spines in a whorl '015 mm. Colour in spirit,

yellowish white ; tentacles light brown. Habitat : Zamboanga, Philippine Islands,

10 fathoms (' Challenger ' CoUectiou).

The characters which separate this species from the preceding are the mode of

branching, the size of the anthocodiie, and the shape and size of the spicides.

B. Anthocodia' pedicellate, home in racemes on the hranchlets.

4. Lemnalia nitiua, Verrill. (Pi. 40. figs. 4, 5 ; PI. 41. figs. 10, 15 ; PI. 42. fig. 18.)

Ammothea nitldii, Verrill, Bull. Mas. Comp. Zool. Harvard, vol. i. p. 39.

Lemnalia nitida, Gray, luc. tit.

Anthodete consisting of a stout, smooth stem, some 8 to 9 mm. high by 6 to 7 mm.

broad; this, after attaining a height of 10 to 11 mm., again divides, generally dicho-

tomously, and the secondary branches thus formed subdivide two or three times to form

terminal branchlets, on which alone the anthocodiaj are borne. The branchlets curved

inward towards the axis of the anthodete. Anthocodise subglobose, shortly pedicelled,

borne terminally and laterally on the branchlets at intervals of 1 to 2 mm. ; the

SECOND SERIES. — ZOOLOGY, VOL. VII. 73

^30 MR. G. C. BOURNE ON THE GENUS LEMNALIA AND

tentacles, Avlien at rest, infolded, but not closely pressed against tlie oral disc. There is

usually a group of three to four anthocodi;e at the end of each branchlet, but no

distinguishable termmal anthocodia. Spicules of the stem and branches of two kinds : —

1. Elongate fusiform, with numerous closely-set, small, warty or spinous projections;

average length, -6 mm. ; average diameter in the thickest part, '025 mm. ; some of the

fusiform spicules shorter and thicker, from -35 to '02 mm. in length by -03 mm. in thickness,

sliglitly curved, covered with prominent spiny projections, and presenting every stage

intermediate between the ordinary fusiform spicules. 2. Modified double stars mth

two elongate rays, measuring from -lo to '08 mm. from tip to tip of the elongated rays

and from -025 to 0"15 mm. in thickness. Tentacular spicules flat, scale-like, finely

sculptured, varying from -075 X 02 mm. to -OSX'Ol mm. Colour in sjiirit, glistening

white. Habitat, Zanzibar.

5. Lbmnalia terminalis, Quoy & Gaimard. (PI. 40. tig. (J ; PI. 41. tigs. 11, 1(5.)

Alcyonum terminale, Q. & G. Voyage de ' rAstrolabe,' Zool. iv. p. 2%2, pi. xxiii. figs. 15-17.

LemnaUa terminalis, Gray, loc. cit.

Anthodete consisting of a short, stout, smooth stem, from the upper end of which several

short, stout branches are given off. These form secondary, stoutish, smooth branches from

which long, very slender branchlets proceed. Anthocodiie shortly pedicelled, about

"6 mm. in diameter ; the tentacles loosely infolded over the oral disc, borne only on the

•slender branchlets at rather wide intervals. Diameter of a branchlet about "75 mm.

Spicules of stem and branches of tAvo kinds : — 1. Elongate fusiform, with few but

prominent spinous projections, those towards the middle generally considerably larger

than the others ; length "7 to "3 mm., greatest thickness -04 to -03 mm. 2. Doulde stars

with two elongated rays, the latter rather sliort and stout ; length from tip to tip of the

elongated rays about '15 mm., greatest thickness about "03 mm. Tentacular spicules

flattened, sculptured, generally X-shaped, sometimes with smooth shaft and bilobcd ends

covered with warty jirojections (tig. 16), measuring from -065 x '02 mm. to -035 x '005

mm. Colour in spirit, yellowish white ; tentacles light brown. Habitat : Port Molle,

Queensland ; King George's Sound.

The specimen in tlie British Museum forms part of the collection made by H.M.S.

' Alert.' There can be little doubt that it is identical Avith the species described as

Alcyonum terminale by Quoy & Gaimard from a fragment brought from King George's

Sound.

Douhtfiil Sjjecies.

Lemnalia kamosa.

Alcyonum ramosum, Quoy & Gaimard, /or. cit. pi. xxiii. fig.s. 8-11.

" Alcyonum magnum, molle, multiramosum, stirpe albicante, fulvo striato, polypis fuscis

in extremitate ramorum coadunatis ; teutaculis breA'ibus rotundatis."

I think that this form must belong to Lemnalia because Quoy & Gaimard's figures

of the anthocodise closely resemble those of L. terminalis. They are further described

as follows : — " Les polypes disposes en grappes a Fextremite des rameaux ne rentrent

point dans leui" gangue corticale. II n'y a que les tentacules seuls qui se replient sur

eux-memes en se fermant comme les petales d'une fleur C'est a I'extremite des

THE BRANCHING-SYSTEMS OE THE ALCYOKACEA. 531

nombreuses branches que les polypes sont agglomeres en panicules ovoides. Chaqiie

individu a un pedicule distinct, court, d'un In-un rougeatre, ou couleur de bistre, de

meme que les luiit tentacules, obtus et arrondis, qui le termiaent."

Anatomi/ and Ilislologij.

The description given, in the introductory part of this paper, of the mode of aggrega-

tion of the Nephthyidie applies in every jjarticular to Lemnalia. I made several series ot

sections through branches and a few sections through the stem of L. nitida, and I was

able to make a series of sections through detached branches of L. rhahdota and L. peri-

styla. I was not al)le to examine the other species microscopically.

Fig. 19 (PI. 42), which is a section of a tolerably large branch of L. nitida, shows that its

branches (and the same is the case with the stem) are composed of fused elongate anthosteles.

It can be seen that the middle of tlie branch is occupied by some ten or twelve large

anthosteles, whose cavities measure some -75 mm. in diameter, wliile the cortical portion is

occupied by smaller anthosteles whose cavities vary from "!') to "1 mm. in diameter.

Nearly all the cavities display ridges or folds which are the prolongations of the

mesenteries. The tissues in the centre of the branches and stem were badly preserved,

so that I could not make out the details of the mesenterial tilaments in all cases ; but in

some sections, both of the stem and branches, I could distinguish tne characteristic

grooved and ciliated asulcar or "dorsal" filaments, and the remaining mesenteries seem

to bear tilaments down to the very base of the colony. The larger central anthosteles

are the chief zooids, the more peripheral anthosteles the secondary and tertiary zooids

of the syndete. The former may be called the chief members, the latter the lateral

members of the branch. It can be seen that the chief members do not communicate

one with another, but that, as at m. m., they communicate by short and wide solenia with

the lateral members, and also that, as at n. i/., some of the lateral members of larger size

communicate by similar solenia with lateral members of smaller size. It is obvious that

there are very few solenia in Lemnalia nitida, and that those Avhich exist are almost

exclusively confined to the cortical part of the branch. What is true of the branch is

also true of the stem.

If lateral members, such as those marked m in fig. 1!), be traced downward from their

solcnial connection with a chief member, they are observed to gradually thin out and

end in a cul-de-sac. If they are traced upward they can l)e followed through a large

number of sections, gradually increasing in diameter, till eventually they emerge on the

surface as anthocodias. In other words, the lateral members do not rise directly from the

chief members, but indirectly, through the intervention of solenia, and they grow both

acropetally and basipetally, bnt their basipetal growth is inconsiderable and may be

neglected. Although the lateral members originate indirectly from the chief members

in this manner, they may be regarded, for present purposes, as springing directly from

them, for by so regarding them we may form a clearer idea of the branching-system of

the anthodete.

The branch of which a section is represented in tig. 19 broke up into a number of

branchlets l)earinu: anthocodice. The group of anthosteles marked A, B, C (chief members)

73 *

532 ME. G. C. BOURNE ON THE (lENUS LEMNALIA AND

and a, h, c, d, ^.y (lateral members) were traced into such a branchlet, of whicli a section

is represented in fig. 20 (drawn to a larger scale than fig. 19). It is seen that, whereas

the three chief members retain their predominant size and occupy the bulk of the section,

the lateral members of the branch have diminished in number. Thus a is emerging as a

small authocodia ; h and e have disapjieai-ed, having come to the surface in similar

fashion lower down on the branchlet ; c, d, and /"have increased in size relatively to the

chief members and will emerge as anthocodite higher up on the branchlet. The two

lateral membei-s marked .c and i/ were not jH'esent in the branch. They took their origin

from solenia growing out of the chief members in the branchlet after its separation from

the branch, ,v arising from A and >/ from B. In the more distal part of the branchlet,

fresh solenial outgrowths of the chief members give rise to new lateral members Avhich

end in anthocodiae towards the tip of the branchlet. The three chief members A, B, and

C can be traced to the extreme tip of the In-anchlet, where they emerge to form a terminal

group of three anthocodite. The larger lateral members (• and d emerge next below the

terminal group, and /next below these. Now, if the branch represented in section in

fig. 19 be traced downward into the stem, it is found that all the lateral members a, b,

■c, d, e,fmonev or later make communication with the chief members A and B (in this

particular instance C does not give rise to lateral members in the branch and stem),

and end blindly below. A, B, and C can be traced down into the stem, where they form

lateral membei-s aud in turn make commiuiication with a chief member of the stem, thin

out, and end blindly Ijelow. Due or two of the most centrally placed chief members of

every branch are continued downward as chief members of the stem. From what

precedes, it follows that the growth of the chief members of the branching-system of the

anthodete is not arrested when they give off lateral members, but that they continue to

grow in advance of the lateral members derived from, and form the main axes of, the

branches and branchlets. Tiuis, as was explained in the introductory part of this paper,

the whole branching-system of any one primary zocid may be compared to a compound

raceme of which the lateral members run parallel one to another, aud are organically

fused together throughout the greater part of their com-ses. The whole anthodete is the

result of the organic union of several such branching-systems. But the racemose mode

of branching is not indefinite in L. iiitida. Some of the more superficial lateral members

of a branchlet are arrested in growth, but continue to branch on the system of a mono-

chasial cyme. Thus, the anthostele a in fig. 20 ends in au authocodia at the level of the

section, and does not grow further as an individual member. But as the sections are

lollowed iipward it is seen that the anthostele sends up a solenium lying in the angle

formed by A and c, and this solenium, some 2 mm. higher up, gives rise to the buds

represented under a liigh magnification in fig. 21. The anthostele marked x has exactly

the same relations. We find therefore in Lemnal'ia nitida a feature common in many

plants : namely, that the ultimate lateral members of a composite branching-system adopt

a mode of branching different from that of the chief member and its primary branches.

It is to be noticed that in L. nitida, and the case appears to be similar in L. termiitalis,

there is not one, but three or four chief members in each branchlet. In Lemnalia

Jukesii, rhahdota, aud peristyla, the arrangement is simpler, for there is only one chief

member in each branchlet, and this emerges at the tip as the terminal authocodia.

TJIE BEANCHING-SVSTEMS OF THE ALCTONACEA. 533

Further, I have not beeu able to discover that the lateral members of these three

species ever branch on the principle of a monochasial cyme, as is the case in L. nitkla.

Sections through branclilets of L. rhahdota and L. perlstyla show that all the lateral

members communicate, either directly or indirectly, through the intermediary of lateral

members of the first order, with the chief member forming the axis of the branchlet.

Thus in these species the mode of branching is that of a compound raceme, without

additional complexity. It appears that the more comjjact arrangement of the anthocodise

on the branchlets of these three species is due to their simpler mode of branching as

compared Avith L. nitida.

I have entered into these questions at some length because the mode of aggregation

and the system of branching in the Alcyonaria have been insufficiently studied and are

imperfectly understood.

Botanists have provided us with a terminology apj)licable to every conceiA'able mode

of branching, and it is possible, by making use of their system, to throw light on many

obscure points in the .Vlcyonaria.

Anatoxin i)f the Zoo'nh.

Fig. 18 (PI. 42), is a drawing of a group of terminal anthocodiicfrom a branchlet of Z. nit Ida

which has been decalcified, stained in alum carmine, and made transparent in oil of cloves.

The tentacles are sliort and broad, provided with a single marginal row of pinnu.les,

their bases confluent so as to encompass a capacious hollow, the oral disc, into which the

tentacles can be infolded. The mouth-opening is circular, rather large in L. nitida,

small in L. p^i-isti/la ; the stomodiBum long and pyriform, its smaller end directed

downward. The ciip-shaped oral disc and the upper wide region of the stomoda3um are

lined by a tall columnar epithelium containing a few gland-cells, but no nematocysts, so

far as I could see. I could not detect any trace of cilia on the epithelium of this region.

Tlie uppermost swollen part of the stomodaeum is oval or subcircular in section, and is

not so much compressed from side to side as is usual ia the Alcyonaria. There is no

sulcus in its ujipor part, but towards its narrower end the cells lining its outer or abaxial

wall change their character, become attenuated and elongated, and bear each a single

very long cilium. This strip of modified epithelium forms a shallow gutter which

is undoubtedly a sulcus, but further down, in the nai-rowest part of the stomodseum,

a definite sulcus can no longer be spoken of. In this r(>gion the stomodfeal tube

is compressed laterally, and is lined throughout by a modified ciliated epithelium

resembling that of the sulcus. In some cases the sulcar groove disappears entirely, and

the cavity of the stomodaeum is a simple oval as represented in fig. 21 ; but more

frequently the cells on the long sides of tlie oval project further into the cavity than

those at the two narrower ends, so that the section is keyhole-shaped with a groove at

either end. But one cannot speak of a sulcus and sulculus in this case, for the epithelium

luiing the tube is of the same character throughout. Such an arrangement has not, so

far as I am aware, been described in any other Anthozoiin *, and it may be regarded as a

* Ashworth, Proc. Eoyal Society, Ixiii. (1^9^i) p. 443, describes the stomodieum of Xenia as having a well-inarkcd

siphonoglyphc (sulcus) in which the ceils ot the lower tliird only bear long fiagella.

534 ME. G. C. BOUENE ON THE GENUS LEMNALIA AND

primitive condition from which the single sulcus of the Alcyouarian, or the sulcus and

opposite sulculus of the majority of Zoantharian zooids, may have been derived. In

L. rhabdota and L. perhtijla the stomodfeum is not so long as in L. nltida, but it has

the same shape and the same arrangement of cilia.

The Mesenteries. — In all three species of which I cut sections all the eight mesenteries

are continued to the lowest ends of the anthosteles. They are therefore continued into

the so-called stem-canals, i. e. the anthosteles of the primary zooids. This is also the

case in Siphouogoryia, but in some other meml)ers of the ]\ephfhi//'d(P, e. g. Spongodes,

only the asulcar (dorsal) mesenteries are continued into the anthosteles of the stem. At

a short distance below the stomodseum the mesenteries are reduced to minute folds or

ridges, and it is hard to distinguish a mesenterial filament on the sulcar and lateral pairs.

But the asulcar pair bears the characteristic ciliated gutter throughout its extent. My

specimens were not sufficiently well preserA'ed to admit of detailed study of the mesenterial

filaments. The longitudinal muscles on sulcar aspects of the mesenteries are poorly

developed, and, as they are not borne ou the longitudinal pleats of the mesogtea, one

cannot speak of muscle-banners. In L. rludjdoia, and particularly in L. perisUjla, the

longitudinal muscles are better developed at the upper ends of the mesenteries, and form

a diagonal Imnd passing from the body-wall to the oral disc. In these species also there

is a considerable development of ectodermic musculature at the bases and along the

inner sides of the tentacles. Slips of muscle-fibres are also given off to the jiiiinules.

These muscles are not nearly so well developed in L. nitida ; and it will be remembered

that in the two first-named species the tentacles can be very tightly infolded into the

oral disc, whereas in L. nitida thev are only li<?htlv folded over. I could find no traces-

of gonads in any of the species which I examined.

Histology.

When specimens have lain for many years in spirit, one cannot expect their histo-

logical details to be faithfully preserved. My example of L. j-habdotn was badly

macerated ; those of L. jjeristyla and L. nitida were better, and I « as able to make out

a few points.

The ectoderm of the oral disc and stomoda^um has already been described, and its

structiire is shown in fig. 21., which is a longitudinal section of a very young anthocodise

In fully -formed anthocodiye the tentacles and pinnules are covered with a cubical

epithelium, continuous witli and generally similar to that of the oral disc. At the bases

of the tentacles the superficial ectoderm becomes flatter, and it is reduced to a single

flattened layer of cells over the greater part of the anthodete. In some places, however,

and especially Avhere new spicules are being lormed and the syndete is being consoli-

dated by the thickening of the external walls of the anthosteles, groups and patches of

columnar ectoderm-cells are found, and these are proliferating rapidly from their lower

extremities. In this manner little nests of rounded cells arc formed, lying on or in the

mesogloca. The mesogloea, as is shown in figs. 22, 23, and 24 (PI. 42), is honeycoml)ed with

irregular spaces, most of which are occupied by spicules. In decalcified sjoecimens, the

organic residue of a spicule may generally be seen occupying the centre of a mesoglceal

space {s.sli. in figs. 22 and 24). Some of the spaces, however, especially those near the

THE BKANCillNG-SYSTEMS OF THE ALCYONACEA. 535

surface of the mesoglcea, are not occupied by spicules, but by groups of rounded or

irregular colls which, as may be seen at scb. in figs. 22 and 24, are clearly derived from

proliferating ectoderm-cells. In sections tliat have been double-stained with saffranin or

picro-carmine and picro-nigrosin the mesogloea is coloured blue, which takes a deeper

or lighter tint according as the structureless matrix is of firmer or softer consistency.

Pigs. 22 and 2i< show that the mesogloea near the surface is full of spaces and is in most

■parts soft and lightly stained. Eurther, that not only are the spaces generally occupied

by cells derived from the ectodenu, but that processes of mesoglcea, marked tiir/', appear

to stretch outward between the ectoderm-cells themselves and to isolate individual cells

or groups of cells. In fact, wo have here the mesogloea in course of formation as an

intercellular substance. The ectoderm-cells proliferate, and while proliferating they

secrete the jelly-substance of the mesogloea. Eventually a honeycomb of mesogloea is

formed, in the cavities of which groups of proliferated cells are enclosed. These enclosed

cells are the scleroblasts, and as they become more deeply situated they give rise to

spicules in the usual manner. In many cases I have found minute spicule-sheaths,

stained deeply by saflfranin and with traces of the organic axis of filaments in their

interiors, among the proliferating cells just l)olow the surface of the ectoderm, but they

are so minute that I have not been able to figure them satisfactorily. It is clear, then,

that the mesogloea increases in thickness during the growth of the anthodete as a result

of the activity of the ectoderm-cells, and that, as it increases, scleroblasts, budded off

from the ectoderm, are enclosed in it and give rise to spicules. I have described a

similar origin of the mesogloea and scleroblasts in Heliopora cccrulea *, but in this case,

as no spicules are formed, the subsequent history of the scleroblasts is different.

The endoderm in the deeper parts of my specimens was so much macerated that I can

say nothing definite about it ; but it was generally fairly well preserved in places

where new growth was taking place, especially in young buds. In all the superficial

parts of the anthodete zooxanthelhe occur al:)undantly in the endoderm, aiid wliere the

latter has undergone extensive maceration they lie loose in the coelenterou. The best

preserved parts of my specimens indicate that the endoderm is much vacuolated, and

that the zooxanthelli^ are contained in tlie endoderm-cells. In some cases (see fig. 23,

zx^ loose zooxanthellae are contained in cells which may be Avandering cells. Zooxan-

thellfe are specially abundant in the cavities of the tentacles aiul their pinnules, and the

more one studies Alcyonarians the more one is strixek by the accumulation of these

organisms in the parts most exposed to the light. One very rarely finds any traces of

food in the coelentera of Alcyonarians ; and its absence and the accumulation of symbiotic

zooxanthelkc in the nutritive layer, the endoderm, point to the conclusion that the

Alcyonaria are, in many cases at least, truly symbiotic organisms depending chiefly, if

not exclusively, on the zooxauthelkie for their nutrition. Mr. Stanley Gardiner's f

recent and conclusive experiments on the evolution of oxygen by corals living expanded

in sunliglit gives weighty support to this view.

* Philosophical Transactions, vol. clsxxvi. (ISiJo).

t Proo. Camhridge Philosophical Society, vol. ix. (189-<», pp. -irS2-4S4. Mr. (jardiiar, however, Joes not attribute

;the evolution of oxyi;en wliolly to the zooxaiithelhc.

536 ME. G. C. BOUENE ON THE GENUS LEMNALIA AND

Finally I have a few words to say on the formation of huds in LemuaUa. A bud,

from which a new zooid grows, is always formed on a solenium which reaches out

towards the surface. An early stage is shown in fig. 22. The solenium, sol., expands

close to the surface to form a wide cavity, the body-cavity of the future zooid. The

endoderm-cells lining the outer wall of this cavity become longer and more columnar

than in other parts ; their nuclei arc more numerous and stain more readily, and

numerous zooxanthellse are accumulated in them. The outer wall of the cavity is only

separated from the ectoderm by a very thin sheet of mesogloea, and outside this the

ectoderm proliferates rapidly, forming a solid plug, which carries tlie mesogloea and

endoderm before it towards the interior of the cavity. This plug is the beginning of the

stomodseum (tig. 23, st.). In the next stage the mesogloeal lamina at the bottom of

the plug is broken through and the ectoderm becomes continuous with the endoderm ;

the centre of the plug becomes hollowed out, and the cells arrange themselves as an

epithelial lining of the tube thus formed. The mesenteries make their appearance at

an earlier stage as folds of the elongate endoderm-cells at the lower end and sides of the

still solid plug (fig. 23, mes.). Shortly after the stomoda.Him has become a hollow tube,

the cells at its lower end are differentiated to form the elongate columnar ciliated

epithelium already described (fig. 24, st."). The oral disc and tentacles are developed

subsequently, the latter as simple digitiform outgrowths of all three layers in the

neighbourhood of the mouth.

I have elsewhere referred to the minute structure of the spicules of LemnaUa * . The

elongate fusiform spicules are excellent objects for study, because of their small size and

transparency. Fig. 17 shows that each has an axial core, from wliich offsets radiate

outward, nearly at right angles to the core, and every such offset forms the centre of

one of the sj)inous projections. In some of my sections tlie organic matrix of the

spicules was well preserved, and stained deeply with htematoxylin. This matrix consists

of an external sheath and a central branching axis of organic fibrils which correspond

exactly to the axial core and its offsets as shown in figs. 17, 8«, and 11 h. The spicules

have, in fact, exactly the same structvu'e as those of Sjwngodcs, described in detail in my

paper referred to above.

The more important points dealt with in this pajierare: — 1. The description of the

branching-systems of the Alcyonacea in general and of LemnaUa in particular. 2. The

restoration and amended description of Gray's genus LemnaUa, with an account of some

new species. 3. The occurrence of a narrowed, uniformly ciliated tube in the lower

part of the stomodseum of LemnaUa. 4. The oi'igin of the scleroblasts and the growth

of the mesoglcea in this genus. 5. The manner in which new zooids are formed from

solenial outgrowths, ti. A new set of descriptive terms applicable in particular to the

Order Alcyonacea.

Oxford, January 14. IbUD.

* " The Stnuture and roiOiiitiou of tlic Cnlcaifoiis Skeletc ii in the Aiitliozoa," Qiuirt. .loiini. Slici-. Scicrico, vol. >;Ii.^

(1899), p. 499

THE BIUNCHING-SYSIEMS OF THE ALCYONAUE.\. -537

EXPLANATION OF THE PLATES.

Plate 40.

Fig. 1. Lemnalia Jukesii. A group of lateral zooids, magniticd lo times.

Fig. 2. Lemnalia rhabdota. A terminal branchlet, x 15. Z^, tcrniiual zooid; Z/., lateral zooid.

Fig. 3. Lemnalia peristylu. A terminal brariehlet, x 15. Zt. and Zl. as in fig. 2.

Fig. 4. Lemnalia nitida. An antliodetc of natural size.

Fig. 5. A terminal branclilet of Lemnalia nitida, x 15.

Fig. 6. Vaxi oi a.\ivs.nc\\\ei oi LeniiHilia lenninalis, x 15.

Plate 41.

Figs. 7, la-Id. Spicules from tiie stem and uutliocodi;e ut'L. Jukesii.

Fig. 8. Lemnalia rhabdota. — 8 a and 8 b. Elongate fusiform spicules from the partitions between the

anthosteles. Sc-Se. Modified double stars from the stem-wall, S^/ being a form intermediate

between the spindle and the double star. 8 b magnified 145, the remainder 240 times.

Fig. y. Lfinnaliaperistijla. — 9 a-9 c. Fusiform spicules from the stem-partitions and branches. 9 d and

9e. Double stars from the stem-wall. 9c and 9d are intermediate in form between 9 a and 9 e.

9 a and 9 b magnified 145, the remainder 240 times.

I'ig. 10. Lemnalia nitida. — 10 «-10 c and 10/. Fusiform spicules from partitions and branches. 10 d, 10 e,

and lOy-10/. Irregular spicules and double stars from the stem-wall. Note the intermediate

forms \Qd, \0,q, 10 A. 10 </ and 10 i magnified 115, the remainder 2i0 times.

Fig. 11. Lemnalia terminalis. — ll«-llc. Fusiform spicules from partition- walls and branches. \\ d

and lie. Doul)li^ stars from the stem-wall. Note the a\ial cord ax and the radial cords ra,

in 116. Magnified 240 times.

Fig. 12. Scale-like spicules from the tentacles and pinnules of L. Jukesii, x 420.

Fig. 13. Bilobed scales from the tentacles ami pinnules of L. rhabdota, x 420. 13 « is a scale viewed

under the polariscope.

Fig. 14. Vai-iously shaped spicules from the tentacles and pinnules of L. peristyla, x 420.

Fig. 15. Scales from the tentacles of L. nitida, X 420.

Fig. 10. Scales from the tentacles of L. terminalis, x 420.

Fig. 17. A spicule of L. rhabdota showing the a.xial core ai\, from which cords ra. radiate outward

and emerge on the spines, x 240.

Plate 42.

Fig. 18. Lemnalia nitida. Terminal aiithoodiye of a branclilet which has been decalcified, stained, and

rendered transparent. T., Tentacles ; or., oral disc ; M., moutli ; st.', upper nou-ciliated wide

moiety of the stomodaium ; st." , its lower tubular ciliated part ; mes., mesenteries.

Fig. 19. Transverse section of a branch of L. nitida, x 35. The mesoglcea is represented in grey, and

the mesenteries are indicated ; all other details are omitted, mm., Solenial connections

between chief anthosteles and lateral anthosteles ; nn., lateral anthosteles giving oft" solenia

from which new zooids will be formed. For the remainder of the lettering in this and the

next figui'e see text, pp. 531 & 532.

SECOND SEKIES — ZOOLOGY, VOL. VII. 74

538 ON Tin: BRANCHING-SYSTEMS OF THE ALCYONACEA.

Fig. 20. Transverse section of a branchlet borne on the branch of whieli a section is represented in

fig. 19. X 60. a., A young- authocodia.

Fig. 21. Transverse section of the lower end of the storaodceum of L. nitlda, showing the uniform lining

of columnar ciliated epithelium, mes., Mesenteries ; t:n., endoderm. Zeiss' ^ Horn. Innn.

Comp. Oc. 4.

Pig. 22. Transverse section through a soicuiium of Leiiiaulia nitida in which a zooid is beginning to be

formed, X 4)20. ec. Ectoderm ; ew., endoderm ; m^., mesogloea; so/., solenia ; s/., thickening

of ectoderm forming the primordium of the stomodasuiu ; sch., scleroblasts budding off from

the ectoderm; s.sh., spicule-slieath.

Fig. 23. Vertical section through another zooid bud, showing the formation of the mesenteries, mes,.

Mesenteries ; zx., a zoo.xanthella enclosed in a cell. Other lettering as in fig. 22. Zeiss' ^.^

Horn. Imm. Oc. 2.

Fig. 2-1. Vertical section through an older zooid bud. st.', Non-ciliated upper, and st.", ciliated lower

regions of the stomodteuni ; mg.' . mesogloea in course of formation between ectoderm-cells.

Other lettering as before. Zeiss' jV Horn. luim. Oc. 2.

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ANA'l'OMV AND HISTOLOG-V OF LEMHALIA.

LINNEAN SOCIETY OF LOiNDON.

MEMORANDA CONCERNIiNG TRANSACTIONS.

The First Series of the Transactions, containing both Botanical and Zoological contributions, has been completed

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The Second Series of the Transactions is divided into Zoological and Botanical sections. The prices of the

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wrapper ) ; —

Second Series. — Zoologv (continved).

Voliinie

2nd Ser. ZOOLOGY.]

[VOL. VII. PART 11.

AUG 10 1900

THE

ryy

rEANSACTIONS

OF

THE LINNEAN SOCIETY OE LONDON.

TITLEPAGE, CONTENTS, AND INDEX.

^LONDON:

PRINTED FOR THE LINNEAN SOCIETY

BY TAVr.OK AND FRANCIS, RKI) LION COURT. FLEET STREET.

SOLD AT THE SOCIETY'S APARTMENTS, BURLINGTON-HOUSE. PICCADILLY. W.,

AND BY LONGMANS, GREEN, AND CO., PATERNOSTER-ROW.

March 1900.

I N D E X.

[Note. — Synonyms and Native Names are printod in italics. A star is added to names which appear

to be used for the first time.]

Aard-vark, African, 294.

Aard-varks, 279, 292-294.

Abralia, mentioned, 1.

andamanica, Goodrich *. 9 ;

mentioned, '2'A.

lineata, Goodrich *, \0 ; men-

tioned, 23.

Acanthias, mentioned, 152.

sense-organ in, 1.52.

Acanthogammarus, ^tehbiny *, 430.

armatus, Di/hou'skif, 430.

Cabanisii, Dijhoii'sL-ij, 430.

Godlewskii, JJi/bowsky, 430.

parasiticus, Dyhoivsky, 430.

Rodoszkowskii, Dijhowslcy, 430.

Zieukowiczii, Dyhowshy, 430.

Accipitres, 208.

diurnas, mentioned, 266.

Accipitrinso nocturna\ mentioned,

266.

Acipenser, mentioned, 146. 147.

^goceras, Waayen, emend. Zittel,

95 ; mentioned, 76.

capricornum, ScMotheim, 95,

112.

laqueolum. ScJdocnbach. 96, 112.

Portlookii, Mriyht, 97.

.ffigoceratidas, Neumai/r, emend. Zit-

tel, 76, 93.

yEpyprymnus, 510.

Alcyonacea, On the Genus Lemnalia,

Cr-ray ; with an Account of the

Branching-systems of the Order,

by Gilbert C. Bourne, 521-538.

Alcyonaria, 533.

Alcyouidie, 523.

Alcyonium, -524.

digitatum, Bicksoii, 521 : ana-

tomy of, 521.

SECOND SERIES. — ZOOLOGY,

Alcyonium terminak', Quay 4' Gaim-

ard, 520, .527.

Alcyonum <ej-)nj>ia/(',UuoyitGaimard,

530 ; mentioned, 532.

raiiiosiiiii. Quoy & Gaimard, 530:

mentioned, 526.

Allorchestes, Dana, 398.

ansiralis, Bate, 410.

/mstrdlis. Dana, 410 ; men-

tioned, 411, 412.

com/iressa, Dana, 410.

compressus, Dana, 410 : men-

tioned, 431.

dentatus. var. graciUcornis,

Fo.ciin, mentioned, 408.

(Taijiiardli. Bate. 410 ; men-

tioned. 412.

Gaiiiiiirdii'!, Dana, 410; men-

tioned. 411. 412.

humiJis, /A/uf/, 413; mentioned,

432.

hinndix, Bate, 413.

longistilus, Fa.roH, mentioned,

408.

malleolus. Stcbbiny *, 409 ;

mentioned, 431,

phimicornis, Heller, 412; men-

tioned, 4.32.

rectus, G. M. Thomson, 402.

(Hyale?) compressa, Delia Vidle,

410.

Amblyopoda, 392.

Ambly stoma, 140.

Amaltheida;, 0. Fisclicr, 76, 85.

Amaltheus, Montfort, 86; mentioned,

76.

spinatus. Brtiyuierc, 86, 111.

Amatliella, Gray, mentioned, 423.

Amathia, Kathlr, 423.

VOL. Vtl.

Amathia Sabinii, Bate, 423.

Amathilla, Bate Sf Westw., 423.

Amia, 116, 119, 1.35, 145, 146, 147,

149, 151 •, 171, 172, 180-184, 191,

196, 199.200.

lateral-line scale in, 149.

Amiunis, 132 ; mentioned, 149, 169,

180, 189.

auditory nerves of, 1 95.

sense-organs of, 149

catus, 131.

Ammonites. 76, 85.

bicurvatus, Trantschold, 71.

discus, J. Sdwcrby. mentioned,

85.

stcraspis, 71 .

[ = Oppelia] steraspis, mentioned,

101, 108.

Ammonoidea, On the Muscular At-

tacliment of the Animal to its

Shell in .some Fossil Cephalopoda.

By G. ('. Crick, 71-11:',.

Ammotliea, .526, 527.

nitida, Verrill, 529 : mentioned,

.525, 526.

virescens, Sav., 526.

Amphibia, 323, 375.

Amphdayns. Pomel, 435, 43(i. 438,

439.

anfiquHs, Schlosser, 436, 440.

Amphioxus, 151.

Amphipoda from the Copenhagen

>luseum ana other Sources. By

Rev. Thos. E. R. Stebbing, Part I.,

25-45 : Part II., 395-432.

Amphithoe (iayi, Nicolet, 425.

jiidiescms, Dana, 426.

Anamixis, Stebbing *, 35, 45.

Hanseni, Siebbiny*, 36, 45.

75

640

INDEX.

Anastomosis, lateral-line, 147.

^forpbolog}- of Jacobson's, 14.5-

148.

somatic sensory, 147.

visceral sensory or true Jacob-

son's, 147.

Ancyloceras, il'Orhii/ni;, SO ; men-

tioned, 73, 74, 70.

Matheronianum, d'Orhic/m/, SO,

110.

Andania (tbi/s.s(iritiii, Stebbing, '■'>!.

Andaniotes, iStehliinr/ *, 30.

corpulentus, Thomson, 31, 4i).

Arioema, Konig, 449.

n-nin</eiii/i.s, Kiinig, 4-50.

Anomalurida% 473.

Anonifx corpulenttts. (1. M. Thomson,

31.

Anseril'ormes, feathers of, 205.

Ant-eater, Great, 292-374.

Little, 282.

Ant-eaters, 27S-374.

Anthropoid Apes, 332.

Apocrangonyx, Stehhiiir/ *, 422.

lucifugus, Ifaij, 422.

Archa'omys, Fraas, 44!', 4.")it.

SteinJieimensis, Fiaiis. 4.'51 : luen-

tioncd, 450.

Archegosaurus, itnoto 5()7.

Arctopithecus, 352.

Ardea cinercn, mentioned, ftnote

231.

Arietites, Neuniiii/r, emend. Ziltel,

93 ; mentioned, 76.

obtusus, J. Sowi-rhy, U'.'t ; men-

tioned, 94, 112.

raricostatus, Zieten, 94, 113.

Armadillo. Blind, 358.

Giant, 350, 374.

Great, 282, 502.

Armadillos, 278.

Asio, mentioned. 227. 242, 247, 24S,

253, 255, 256, 262, 264, 269,

270.

aceipitriuus, I'dll., 228 ; men-

tioned, 223, 234, 242, 245,

255, 262, 265, 270, 273, 274.

adult, down-feathers of, 257.

otus, Linn., 225, 234, 254, fig.

254 : mentioned, 202, 270,

274.

Asionidse, 269, 270.

Asioninae, 269.

Aspidoceras, Xittd, 10:j ; mentioned,

76.

sp., U«, 112.

Aspidoceratidaj, Zitkl, 76, 102.

Asjjidophoreia dleinencnsis, Haswell,

410; mentioned, 411, 412.

(Hyale ?) ditmenengis, Delia

VaUe, 410.

Asteroceras obtusum, J. Sowerhy,

ftnote 93.

Athene, mentioned, 226.

brama, mentioned, 224.

noctua, mentioned, 259.

Auchenaspis, 151, 170, 171, 172.

184.

Auditory (Jrgan of Fishes, 194-

199.

Axelboeckia, Stehbimj *, 423 ; men-

tioned, 425, 428.

Carpenterii, Di/howski/, 424.

spinosa, Snrs. 424.

BacuUtes, LamarcJr, 77 ; mentioned,

73-76, 108.

ovatus. Say, 77, 109.

vagina, Forbes, 78, 110.

IJaikalogammarus, Stehbiny *, 425.

pullus, Dybows/.y, 425.

Barbus Huviatilis, 169.

vulgaris, 169 ; mentioned, 137,

167.

Bat (iliniopterus Schreibersii), Coro-

nal section through the right

liil)pocampal formation, 68.

Hippocampal llegion in, 58-61.

Bathyergus, 498.

raaritimus, 496.

Bats, 307.

Beard's branchial Sense-organs, 150.

Beluga, 500, 501.

Birceima, (li'dton, 421 ; mentioned,

414.

fulvus, Cluhuii, mentioned, 421.

" Blind Armadillo," 358.

Boeckia, Sars, 423.

Bone. Lachrymal, 123.

Bon}- Palate in the Lagomorphine

.Skull (Forsyth Major), 485-487.

Bourne, Gilbert C, on the Genus

Lemnalia, Gray ; with an Account

of the Branching-systems of the

Order Alcyonacea, 521-.j38.

Brachyuropus, Stcbblny *, 424.

Grewingkii, Dybuwsky. 424.

Beichertii, Dybowshy, 424.

Bradypodidoe, 293-295, 307-390.

Bradypus. 282 284, 306-346.

tridactylus, 282-346.

Brain in the Edentata, by G. Elliot

Smith, 277-394.

Brain System in Edentata, 353.

Brandtia, Bate, 424.

fasciata, Stebbiiu/ *. 424.

lata, Dybowsly, 424.

latissima, GerstfeJdt, 424.

Morawitzii, Dyboivslcy, 424.

smaragdina, Dybowsky, 424.

tuberculata, Dybowsky, 424.

Bubo, 270; mentioned, 224, 226,

240, 243, 256, 260, 264, 269.

ignavus, Forst., 235, 270 ; men-

tioned, 224, 239, 241, 260.

lacteus, Stejdi., 239, 270 ; men-

tioned, 234, 259.

niaculosus, Bjk, 238 ; mentioned,

235, 241, 260, 270, 274.

maximus, mentioned, 240.

nycterus, Linn., 241, 270 ; men-

tioned, 259, 260, 274.

torquatus, Daud., 240, 270 ;

mentioned, 224, 241, 264.

virginianus, Sw. i|- Rich., 236,

270; mentioned, 224, 239,

260.

Bubonidae, mentioned, 226, 206.

Buboninic, mentioned, 226, 227.

Buccal Trunk, 158-161.

CaUichthys, 184.

CaUiteuthis, 1.

reversa, Verrdl, 16.

Caloceras liasieum, d'Orbigny, ftnote

96.

raricostatum, Zieten, ftnote 94.

Canal, Hyomandibular, 126, 130,

182.

or Operculo-mandibular,

161-164.

infra-oi bital, 1 2:'. 1 26, 1 30, 1 58-

161, 1S2.

Lateralis, 127-130, 164, 183.

sensoiy, 120-129.

supra-orbital, 122-126, 130,

156-158, 182.

Canals, innervation of the lateral

Canals in Gadus, 156-166.

Lateral or Sensory Canals, Phy-

logeuy of, 187-194.

Belation of Sensory Canals to

the Skull, 131-1.33.

Sense-organs on the Lateral-

line Canals, 129-131.

Sensory Canals in ;^eiieral, 120-

122.

INDEX.

541

Canals, Sensory, of the Skull, 131-

133.

Cancer (Gammarellus), Herhst, 423.

( ) homari, Herhst, 423.

Cauis, 33S.

Caprimiilgida!, mentioned, 2G7.

Caprimulgus, meiitioued, 23.3. 257,

259, 267, 273.

europ£eu3, down-feather of, 257;

pre-penna of, 257.

Caprolagus, 487, 4S9, 511-515.

hispidus, y'('«»-.,514: mentioned,

ftuote 4(54, 465, 466, 468,

469, 479, 486, 490, 492. 493,

499, 506,508,516,517.

Lacosti, Foiiiel, 51 7.

Net&cheri, Sehler/. 4' Jent., 50S.

sivalensis, Maj., 514, 517.

valdarnensis, IVeiih., 514.

(Caprolagus) hispidus, h'lirs.,

519, 520.

(Nesolagus) Netseheri, Sclder/. (Sf

Jeat., 493, 517, 519, 520.

(Oryctolagus) crassicaudatus, /.

Oeoffi:, 518, 520.

( ) cuniculus, Linn., 515-

519.

(Romerolagus) Nelsoni, Alerr.,

517.

(Sylvilagus) hrasiliensis. Linn.,

516, 518, 520.

( ) Xelsoni, ^Jel^l•., 530.

( ) palustris, Biichm., 517.

( ■) sp., 518.

Cardioceras, Neumai/r i.\- ihlvj, 86 ;

mentioned, 74, 76, 89.

excavatum, J. Soverhij. 75, 78,

86, 111.

funifenim, ./. Phillips, 88.

SutherLindia>, J. dc C. ,'^nw,'rbii.

88.*

sp., 8!», 111.

Carine, mentioned, 227, 244, 264-

266, 27<t, 271.

brama, Tfiiini., 'Job : mentioned,

2(;(i.

noctuii, Scii^i., 25U ; mentioned,

255, 265, 266, 271-

Carinogammarus, Stehhin;/ *, 42it.

atchensis, Brandt, 430.

caspius, J'ldldx, 430.

cinnamomeus, Bi/howsJn/, 4l!9.

Huviatilis, liosel, 430.

macrophthalmus, SlinijjMn, 43u.

mucronatus, Saif, 43t*.

pulchellus, Diilioiusk;!, 429.

Carinogammarus rhodophthalmus.

DiihowsL-ii, 429.

Seidlitiii, Dybowsk;/, 429.

subcarinatus. Bate, 430.

Wagii, Di/howsJiif, 42!t.

Carnivora. 277, 280.

Castor. 502.

fiber, mentioned, ftuote 227.

Cat, brain of, 329.

Cathart-c, 268.

Ceina, Delia Valle. 397.

Centi'tida-, 508.

Cephalopoda, Report on a Collection

of, from the Calcutta Museum. By

Edwin S. Goodricli, 1-24.

Cephalopoda (Ammonoidea), On the

JIuscular Attachment of the Ani-

mal to its Shell in some Fossil

Cephalopoda. ByC C. Crick, 71-

113.

Ceradocus, A. Costa, 42().

fasciatus, 0. G. Costa. 420.

fasciutus. Delia Valle, 426.

orchestiipes, A. Costa, 426.

rubro-maculatus, Stimpsnn,

426.

semiserratus, Bate. 426.

Torelli, Goes, 426.

Ceratites semipartitus, 71.

Cercopithecid*, 508, 509.

Cerebellum in Edentata, 360.

Cerebral Commissures in Edentata,

301.

Ceryle torquata. mentioned, ftuote

231.

Cetaoca, 325.

Cha>tostomus, 171. 172, 184.

Cheiroptera, 280, 330.

Cheiroptera, The Origin of the Corpus

Callosum : a Comparative Study of

the Hippocampal Region of the

Cerebrum of Marsupialia and cer-

tain Cheiroptera. By G. Elliot

Smith, 47-69.

Cheiroteuthidw, 12.

Cheiroteuthis. mentioned, 1, 12, 14,

15.

lacertosa, Verrill, mentioned,

13.

macrosoma, Goudrieh. *, 12 ;

mentioned, 13, 23.

jiellucida. Goodrich*, 14: men-

tioned, 23.

I'icteti, Joiiliiii, mentioned, 12,

13, 14.

Veranvi, Jmdnn, mentioned, 13.

Chelonidium, 396. '

Chiltonia, Stehhimi *, 408 ; mentioned,

397.

miMwaka, Chilton, 408.

Chimtera, 116, 131, 140, 144,

1 53-1. V). 173. 184, 191, 201,

203.

Chiroptera, 375.

Chlamydophorus, 281 , 283-301, 303-

349.'

truncal.us, 282.

Choloepus, 282-302, 306-327.

didactylus, 2S2, 283.

Hoffmauni, 284-327.

Choristoceras ammonitiforme. ftnot«

72.

Chrysochlurida', 49s.

Clmsochloris. 377, 497, 498.

aurea. 498.

Trevelyani, 498.

Circus, mentioned, 2(i6.

Cirrhotenthis paeifica, Hoi/le'!, 19.

Cladodns. mentioned, 193.

Cladoselache, mentioned, 193.

Clarias. 151, 170, 171. 172,

184.

Clymenia. Minister, 105 : mentioned,

"73, 74. 76.

undulata, Miinster, 105, 113.

Coccosteus, 120, 184.

Cole, Erank J., Observations on the

Structure and Morphology of the

Cranial Nerves and Lateral Sense-

organs of Fishes : with special

reference to the Genus Gadus,

115-221.

Columba^ 265.

Condylarthra, 388, 392.

Condylura, 508.

Conger vulgaris, 180.

Contour-feathers, 256.

Conurus, mentioned, 231 .

CoraciiE, 268.

Coraciidic, 268.

Corophiidie, mentioned, 420.

Corpus Callosum, The Origin of the :

a Comparative Study of the Hip-

pocampal Region of the Cerebrum

of Marsupialia and certain Chei-

roptera, by G. Elliot Smith, 47-

69.

Cosmoceratidic, Zittcl, 76, 103.

Cottus, 180.

Crangonyx, 423.

siditerraneus, Vejdovsky, 423.

Creodonta, 385-392.

75*

54i2

INDEX.

Crick, George Charles, On the Mus-

cular Attachment of the Animal

to ita Shell in some Fossil Cepha-

lopoda (Ammonoidea), 71-113.

Crioceras, Lh'eilU. 79 ; mentioned,

73, 74, 76.

quadratum (Bean MS.), Grid-*,

79 ; mentioned, 74, 110.

Ctenomys, 497, 498, 509.

Cuculi, 268.

CuniculuB, .513.

Cycloturus, 282-295, 298-316, 318-

382.

didactylus, 283.

Cyprinus, 168, 174, 194, 199.

barbus, 137, 167.

carpio, 168, 169, 174.

Dasypodidae, 293, 298-390.

Dasypus, 282-298, 317.

sexcinctus, 282-303, 307-317.

viUosus, 282-295, 297-317.

Dasyurus, 56, 58 ; cerebrum of, 66.

viverrinus, 55 ; mesial waU of

cerebral hemisphere of, 68.

Decapoda Myopsida, 2.

Didelphys, 301, 509.

Dikerogammarus, Slebbinrj *, 428.

fasciatus, Sai/, 428.

Grimmi, Sars, 428.

haemobaphes, EicMuald, 428.

macrocephalus, .S«cs, 428.

Verreausii, Bnte, 428.

Dionyx, 382.

Dipnoi, 288, 323, 375.

Distichocerns, Mimier-CJialmas, 100;

mentioned, 76, 101, 109.

Baugieri, trOrhvjny, 100, 113.

Dog, brain of, 333.

Doratopsis, mentioned, 15.

vermicularis, RuppeU, men-

tioned, 14.

Dorsale SchedelhoJileiiast (Stannius),

166.

Down-feathers, adult, of Asio, Speo-

tyto, and other Owls, 257.

Dulichia, mentioned, 35.

Ear, External, 259-263.

Earth-Pig, 388.

Echidna, 56, 330, 496.

Echinogammarus, Stehhimj *, 421.

aheneus, TJi/hotvsl-i/, 429.

Berilloni, Catta, 429.

capreolus, Dybowski/, 429.

cyaueus, Dybowsl-y, 429.

Echinogammarus Czerskii, DylMivsky,

429.

fuscus, Dybowsky, 429.

ibex, Di/boii'sly, 429.

leptocerus, Dybowsl-if, 429.

lividus, Djibowsky, 429.

Maackii, (ierst/ddt, 429.

murinus, Dybowsl-y, 429.

mutilus, Abildgaard, 429.

ochotensis, Brandt, 429.

Parvexii, Dyboivsky, 429.

Petersii, Dybowsky, 429.

polyarthrus, Dybowshy, 429.

saphirinus, Bybowsl-y, 429.

sarmatus, Dyboiuslif. 429.

scharaanensis, Dybowsly, 429.

Sophia", Dyboirn/i-y, 429.

stenophthalmus, Di/bmraky, 429.

testaceus, Bybowxhy, 429.

toxophthalmus, Dybowsky, 429.

TJzzolzewii, Dyboirsk-y. 429.

verrucosus, (Jerstfeldl, 429.

violaceus, Bybowsl-y, 429.

viridis, Dyhowd-y, 429.

vittatus, ByJioivd-y, 429.

Edentata, 302, 502.

Edentata, The Brain in the, by G.

Elliot Smith, 277-394.

Elasmobranch, Sensory Canals of an,

120.

Elasmopus, A. Costa, 426.

Boeckii, J/aswell, 426.

crassimanus, Miers, 426.

Miersi, Wrzemiowshi, 426.

suensis, Haswi'17, 426.

viridis, Ilaswell, 426.

Elephant, brain of, 388.

Embryo, Pterylosis of the. 254-256.

Emydidie, 496.

Emys lutaria, embryo of, 501.

Euoploteuthis Hoylci, Pfiffer, 11.

Equus, 330.

Erinaceus, 292, 502, 508.

europajus, 50.3.

Eryops, ftnoto 507.

Esox, 119, 136.

Eucrangonyx, Stebbiny *, 423.

antennatus, Paclard, 423.

gracilis, Smith, 423.

mucronatus, Forbes, 423.

Paekardii, SmitJt, 423.

Vejdovskyi, Stebbiny *, 423.

Eulagos, 513.

Judaete, 513.

mediterraneus, T>\'\.

Euornithse, 272.

Eusiridae, 39.

Eusiropsis, Stebbiny *, 39, 45.

Riisei, Stebbiny *, 39, 45.

Eutatus, 298, 381.

Eutheria, 277.

Falco, 266.

tinnunculus, 2.53, 257, 259 ;

plumule of, 257 ; pre-penna

of, 257; pre-plumula of,

257.

Falconidje, 268.

Faleoniformes, 268.

Feathers, structure of (Pyci-aft), 256-

259.

Felis, 341.

pardus, 338.

Fierasfer, 180, 187, J 94.

accessory lateral nerve in, 169,

171. "

acus, 180.

dentatus, 180.

Filoplumes, 257.

Fossil Cephalopoda (Ammonoidea ),

On the Muscular Attachment of

the Animal to its Shell in some,

by G. C. (Vick, 71 113.

Gadus, 1 16-119, 132, 150, 155, 181-

184, 199-205; compared with

other Forms, 179-185; innerva-

tion of the lateral canals in, 156-

166; innervation of the .sensory

canals in, 156-166.

aeglefinus, 136.

callarias, 118, 137, 145: nerves

of, 118.

carbonarius, 119, 155.

lota, lis, 167, 168, 169 ; brain

of, lis, 119 ; trigeminus and

cephalic sympathetic of, 118.

morrhua, 118, 122, 172, ftnote

176, 182, 203 ; sense-organs

on the lateral-line canals

in, 129-131 ; sensory canals

of, 122-131, 145.

virens, 117, 119, 121, 125, 127,

129, 136, 155, ftnote 176,

180, 182, 194, 203 ; sense-

organs on the lateral-line

canals in, 129-131 ; sensory

canals of, 121-129.

Gadus, Observations on the Structure

and Morphology of the Cranial

Nerves and Lateral Sense-organs

of Fishes ; with special reference

INDEX.

543

to the Geuus Gadiis, by Frank J.

Cole, 115-221.

GaUiformes, feathers of, 265.

Gammarelhis, Uerhst, 423.

angulosus, liuihle. 423.

carinatus, Hathhe, 423.

homari, ./. C. Fahricw^, 423.

Gammaridffi, 396, 422.

Gammarus, J. Q. Fahricius, 428 ;

mentioned, 396, 425-427, 429.

aheneus, Dyhowshy, 429.

albiilus, Di/howskii, 429.

armatus, Difbowsl-y, 430.

asper, Dana, 422, 426.

asper, Dybowsky, 422.

bifasciatus, Dijhowslcy, 429.

brauchialis, JJybowsky, 429.

Cabanisii, Dybownky, 430.

capellus, Dqhoivsly, 429.

capreolus, Bj/howshy, 429.

cyaneus, Dyhon'slif, 429.

Czerskii, /)i/hoirs7:y, 429.

fasciatus, 0. G. Costa, 426.

Flori, Dyhowsky, 429.

van albula, Dyhowsky,

429.

fuscus, J>yhou'sky, 429.

Godlewskii, IJybowsl-y, 43il.

ibex, Dybowsky, 429.

ignotus, Dybowsky, 429.

indiciis, JJana, 426.

ischnus, Stelibiay *, 42S.

Kriiyeri, llatJd-e, 426.

Krdyeri, Bell, 426.

Jcwgensis, (ierstfeldt, 426.

leptocerus, Dybowsky, 429.

lividus, Dybowsky, 429.

Loveni, BruzeUus, 422.

Lovenii, Dybowsky, 422.

marinus. Leach, 428.

marinus, Risso, 428.

montanus, 0. f/. t'os/n, 425.

murinus, Dybowsky, 429.

mutilus, Ab'ddyaanl, 429.

parasiticus, Dybowsky, 430.

Parvexii, Dybowsky, 429.

Petersii, Dybowsky. 429.

polyarthrus, Dybowsky, 429.

puteanus, Moniez, 425.

Rodoszkowskii, Dybowsky, 430.

saphirinus. Dybowsky, 429.

sarmatus, Dybowsky, 429.

schamanensis, Dybowsky, 429.

Sophiie, Dybowsky, 429.

Sophianosii, Dybowsky, 429.

spinosus, &'o''*, 422.

Gammarus spinosus. Lamarek,

422.

Stanislavii, Dybowsky, 429.

stenophthalmus, Dyboimky, 429.

tenellus, Dana, 428.

tenellns, 8ars, 428.

tenuicornis, Stltnpson, 42.5.

testaceus, Dybowsky, 429.

toxophthalmus, Dybowsky, 429.

Uzzolzewii, Dybowsky, 420.

violaceus, Dyboivsky, 429.

viridis, Dybowsky. 429.

vittatus, Dybowsky, 429.

zebra, if(/;/(7,'(;. 424.

zebra, Dybowsky, 424.

Zienkowiozii, Dybowsky, 430.

Ganglion,

Morphology of the Facial Gan-

glion, 136-145.

Trigemino-facial Ganglionic

Complex, 133-136.

Ganodonta, 278, 387, 392.

Ganoid, 120.

Genetta, 348.

tigrina, 337.

Geomyid;p, 452.

Geomys, 488.

Georychus, 509.

Glaucidiuin, mentioned, 226.

Glyphioceras, //(/f!?<, lOfi; mentioned,

76.

creuistria. .7. P/nlli/is, 106, 113.

truncatuni. .A I'hUI'qjs, 108, 113.

Glyptodon, 282-298, 351, 381.

Gmelinopsis, mentioned, 425.

Goniatites, 76, 106.

Goodrich, Edwin S., llcport on a Col-

lection of Cephalopoda from the

Calcutta Museum, 1-24.

Graia. G'dniher, mentioned, 423.

Grayia, mentioned, 423.

imbricata. Bate, 423.

Ground-sloths, 278-298.

Grus australiensis, mentioned, ftnote

231.

cinerea, mentioned, ftnote 231.

Gymnasio. mentiooed, ftnote 227.

Gymnura, 503, 508.

Gypaetos, mentioned. 267.

Hakonboeckia, Stebbiuy *, 425.

.Strauchii, Dybowsky, 425.

Hamites, Parkinson, 79 ; mentioned,

73, 74, 76, 108.

maximus, J. Vowerby, 79, 110.

Haplodontia, 452.

Hares, 488.

Assam, 512.

Brazilian, 513.

Common, .512.

Forest (Indian), 511.

Hispid, 492, 511, 512.

Indian, 511, 512.

Jackass, 491.

Oriental Black-necked, ftnote

4,S9.

Red-tailed, 511.

Sumatr.a, 493.

Timid, 511.

Variable, 511.

Ifarpinia, ? Stebbing, 32.

pinyuis, Ste))bing, 33 : men-

tioned, 34.

HarpoceratidK, Xeinnayr, emend.

Zittel, 98 ; mentioned, 76.

Hecticoceras, BonarelU, 98 ; men-

tioned, 76.

hecticnm, Rehiecke, 98 : men-

tioned, 100-113.

Hedgehog, 292.

Heliopora cajrulea, mesoglcea and

scleroblasts in, 535.

Hemiganus, 387.

Heptanchus, mentioned, 200, 201.

Heterooeras, d'Orbigny, 84 ; men-

tioned, 76.

polyplocus, lioeviei; 84, 111.

Heterogummarus, Stebhiny *, 429.

albulus, Dyboivsky, 429.

bifasciatus, Dybowsky, 429.

branchialis, Dybowsky, 429.

capellus, Dybowsky, 429.

FloH, Dybowsky, 429.

,var. aJbida, Dybowsky ,429.

ignotus, Dybowsky, 429.

Sophianosii, Dybowsky, 429.

Stanislavii, Dybowsky, 429.

Heteroglaux, mentioned, ftnote 227.

Hexanchus, mentioned, 139.

Holocephalau, 120.

Homo, 368, ftnote 495.

Hippocampal Formation in Edentata

(G. Elliot Smith), 310.

llegiou of the Cerebrum of

Marsupialia and certain Cheirop-

tera, a Comparative Study of, by

G. Elliot Smith. 47-69.

Hippopotamus, brain of, 388.

Histiopsis, Hoyh, mentioned, 1, 16.

atlantica, Uoyle, mentioned, 16.

Hoy lei, Goodrich *, 15 ; men-

tioned, 24.

MA

INDEX.

Histioteuthis, meutioned, 16.

Hysena striata, 338.

Eyale, Bathl-e, 398.

diplodactylus, StMing *, 40."> ;

mentioned, 404, 431.

Galatea, Stehbiiig *, 402 ; men-

tioned, 403, 431.

macrodactylus, Stehbinr/ *, 404 ;

mentioned, 431.

maroubrae, Stebbincf *, 405 ;

mentioned, 431.

media, Dana, mentioned, 405.

Perieri, Lucas, mentioned,

405.

Prevostii, Delia VaUe, 412,

413.

Hyalella, S. I. SwM, 398: men-

tioned, 422.

inermis, »S'. /. Smith, mentioned,

408.

Lubomirskii, Wrzesniowsl-i,

mentioned, 407.

Meinerti, Stebbiiig *, 407 ;

mentioned, 431.

inihiwal-a, Chilton, 408.

Warmingi, Siebbin</ *, 406 ;

mentioned, 431.

Hyalellopsis, Slebblng *, 422.

Czvmia'iskii, Bijbowshi/, 422.

Hybris, mentioned, 225.

(Strix) flammea, mentioned,

225.

Hydrolagus, 513.

aquations, 513.

palustris, 513.

Hylobates, ftnote 495, 496, 498,

509 ; Carpus of. 494.

agilis, 495.

lar, ."iOi).

leuciscus, 494, 495.

Miilleri, 495.

syndactylus, 495.

Hyomaiidibular canal of Fishes,

'l82.

or (Jperculo-mandibular canal,

161-164.

Trunk, 161-164.

Hj^eroodon, 500.

rostratus, 5ilO.

Hystrix. 502.

Ichthyophis, mentioned, 189.

Icilius, Dana, mentioned, 420.

Icridium, Grube, 416.

frt.ici'm. Grube, 417-

leroglaux, mentioned, 226.

Iguana, cerebrum of, 66.

Infra-orbital canal, 182.

Inioteuthis, 1.

japouica {TUesins, MS.), Ver-

rill, 3.

maculosa, Goodrich *, 2 ; men-

tioned, 22.

Morsei, Verrill, 2, 3.

Insectivora, 280-300, 389, 502,

508.

primitiva, 389.

Inuus, 494, 495.

ecaudatus, 494.

Invertebrates and Vertebrates,

Lateral sense-organs of, 185-

187.

Iphigenia, G. M. TJumison, men-

tioned, 42(».

typica, G. M. Tlwiimon, men-

tioned, 420, 421.

Iphinotus, Stehbiiuj*, 419; men-

tioned, 414, 421.

Chiltoni, Siebbing *, 414 ; men-

tioned, 421, 432.

Iphiplateia, Stebbing *, 414 : men-

tioned, 417, 419.

V\'hiteleggei, Sfehbing *, 415 ;

mentioned, 432.

Jackass Hares, 491.

Jacobson's Anastomosis, Morpho-

logy of, 145-148.

Kaiiffaroo. brain of. 380.

Lachrymal Hone, 123.

Lajmargus, 116, 151, 183, 184.

sense-organs of, 159.

Lai/odiis, Pomel, 435, 436, 437,

438, 439.

Fontaniicsi, Depc'ret, 444, 445.

liicoiden, rome), 435, 436, 437,

440, 443.

Lagomorpha, On Fossil and Recent,

by C. I. Forsyth Major, 433-

520.

limb - skeleton of (Forsyth

Major), 487-493.

lower molars of, 480.

Lagomorphous liodentia. Lower

Molars of, 473.

Lagomyida\ 433, 451, 463, 469

474, 494. 502. 506-515.

Tooth-change and Tooth- i

formula in the (Forsyth

Major). 4'!3.

Lagomys, 433-437, 440, 448, 452,

457, 460-4 fJ3, 471-476, 481-

487, 493, 499. 505, 508, 510^

511, 514.

alpinus. ftnote 461, 476.

Corsica II im, It. Wagner, 456,

458.

foxsilis. It. Wagner, 455.

loxodvs. Gervais. 457.

melauostomus, 508.

Meyeri, v. Tschudi, 450.

nepalensis, ftnote 461, 476.

wningcn^ls, H. v. Meyer, 450 j

mentioned, 444, 451, 460,

462, 481, 482.

(fniii.gensis, Waterh., 450.

ogotona, 486.

pusillus, 437, 493.

rufescens, Gra;/. 499, 508, 518,

519, 521 ».

rutilus, Scrirtzoff, 476.

sausaniensis, Lirrtet. 438, 450,

451.

sardus, Lydekker, 456.

sardits fassilis, K. Wagner,

455.

tibetanus, 48(i.

vents, Fraas, 444, 451.

wjvfs, Heusel, 460, 481, 482.

vixeiioi'iensi)!. Lydekker, 436.

[yhnjihi/af/ii/i) antiqinis, Pomel,

4:((;.

(Lui/o/'.iis) II iiiiigiiini)!. Schlosser,

444. 46(t.

( ) vcri's, Schlosser, 444,

460.

( ) Mriis, Hensel, 444.

{Myolagus) Meyeri, H. v.

Meyer, 451.

( ) Meyeri. Tschudi, 450,

451.

( -) sardus, Schlosser, 456.

{Frulai/us) corsicanvs, Deperefc,

457'.

( ), Meyeri, Deperet, 451.

( ) sansaniensis, Pomel,

451.

Lagomys, (i. Guvier, 449.

Lagojiu/s, Lydekker, 436.

Lagomys, Pomel, 436.

Lagomys. Schlosser, 436.

INDEX.

545

Lagopsis, SMossir, 4:53, 430, 448,

400-403, 472-477, 481, 511.

CEuingensis, H. i: Meyer, 482.

leninijeiniis, Schlosser, 400.

' venis, Jleiiael, 460 ; mentioned,

444, 401, 402, 475, 470, 481,

482, 507. 510-518, 520.

venis, Schlosser, 460, 461.

Lagorobestcs, ftnote 485.

Lateral-line system. Metamerism of,

• 148-156.

or Sensory C':in;ils, I'hylogeny

of, 187-194.

Sense-organs of X'ertebrates and

Invertebrates, 1 S5- 187.

Lateralis Cunal. 104-106, 183.

Nerve, Jlorphological Value of

the, of Petromyzon, ITS,

17it.

Trunk, 104-100.

Lemnalin, (li-aii ; On the Ueuns,

with an Account of the Branching-

systems of the Order -Ucyonacea,

by Gilbert C. Bourne, 521-53S.

Lemnalia, ^Trai/, emend. Bourne,

527 ; mentioned, 531, 530.

Jukesii, Grai/, 528 : mentioned,

520, 527, 532, 537.

nitida, rerrlll, 520 ; men-

tioned, 520, .531, 532, .533,

534, 537, 538.

idtkia, (iray, 520.

peristyla, (r. C. Bourne *, 529 ;

' mentioned. 531, 533, .534, I

537.

polystyhi, mentioned. 532,

533.

" ramosa, Quoii tV (immanl,

530.

rhabdota, G. C. Bourne *, 528 ;

mentioned, 520, 531. .532,

533, 534, 537.

■ terminalis, Quoij ij- Indmard,

530 ; mentioned, 520, 532,

537.

t terminal Is, Gray. 530.

Lemur nigrifrons, 331.

Lepidosteus, mentioned, i 47. 199,

200.

Leporidffi, 4.33, 470, 480, 480-489,

494, .502-514.

Upper Incisors of, 405.

Leporine incisors, .Vnterior cmd of

upper, 408.

Leptoptilus javaiiicns, mentioned,

ftnote 231.

Lepus, 323, 373, 433-441, 448,

452, 403, 400-480, 484-489,

499, 505, 510-515.

-Vltaieus, 468.

Americanus, 512.

aquaticus, 513.

.Vudubonii, 512, 513.

brachyurus, 512.

brasiliensis, 491.

ealifornicus, 512.

callotis, Wdijti., 466, 407, 491,

512.

campestris, 512.

capensis, 467, 409.

cumanicus, Tlios., 408, 469.

euniculus, .512.

dayanus, f[ih/end., 406, 467.

408.

europajus. Pall., 464, 466,

469, 480, ftnote 484, 485-

488, .505, 506, 512, 516.

glacialis, 512.

hainanus, ftnote 4(i0, 407,

468.

hispidus. Pearx., 441, 511,

512.

.Judffiae, Grai/, 46S, 400, 513.

kurgosa, Gray, 467, 408.

h)Xodu!t, Gervais, 4.57-

mediterraneus, 513.

melanotis, Mearns, 407.

raexicanus, Lichtenst., 400,

409, 484.

!Netscheri. Schle;/. 4' Jerd., 44,

ftnote 493.

nigricollis. /''. Cuv., 464, 405,

40(), 407, 4li8, ftnote 489,

51(1.

palustris, .513.

pcguensis, Bh/tli, 407, 468.

ruticaudatus, 405, 467, 408,

ftnote 400, 512.

ruticaudatus (kurgosa. Gray),

408.

sasatilis, F. Cur.. 407, 468,

484, ftnote 485.

sinaiticus, 468, 469.

sinensis, (rruii. 468, 469.

sp., 457. 407, 408, 480,

510.

sylvaticus, .512, 513.

transitionalis, 487.

tibetauus, Waterh., 409.

tiraidus, Linn., 4(>y, 489, 500,

.512, 513, 510,519.

Trowbrid^ei, 512, -513.

Lepus valdarnensis, Weith., 441,

487.

variabilis. Pall., 408, 409, 489,

510.

(altaicus), 408.

Victoria, Thos., 407, 408.

vulgaris, ftnote 484.

Whytei, This., 407, 408.

yarkandensis, GuiiiJi., 465,

468, 469.

(Macrotolagus) callotis, 468.

( ) melanotis, Mearm,

468.

Leuciscus rutilus, 108.

Leucothoe, mentioned, 35, 36.

fiirhui, Chevr., 35.

imparicornis. Norm., mentioned,

35.

incisa, Ruherts-on, 35, 45.

Lilljeborgii, BoecJc, mentioned,

35.

spinicarpus, Ahildgaard, men-

tioned, 35.

Leucothoidai, 35.

Limnolagus, .514.

aquaticus, 514.

palustris, 514.

Limorogale, 508, 509.

Loliginei, 5,

Loligo indica, Pf''fftr, 7 ; men-

tioned, 6, 22.

marmora, 0.

Pealei, 6.

Loliolus, 1, 6.

luvestigatoris, Goodrich *, 8 ;

mentioned, 23.

Lopbius, 183.

Lota, mentioned, 118, 157, 180.

vulgaris, 118, 119, 167, 169,

173.

. lateral sense-organs of,

118.

Lutra, 508.

LysianassidtB, 28.

Lysianax cinghalensis, Siehbiny *,

28, 44.

cubensis, Stebhing *, 29, 44.

Lytoceras, Suess., 91 ; mentioned,

76.

cornucopia;, Touny 4' -Bird,

01, 112.

fimbriatum, J. Soiverby, 01,

112.

quadrisulcatum, d'Urbiyny, 92.

Lytoceratidae, Neiimayr, emend.

Ziftel, 70, 01.

546

INDEX.

Macropus, 58, 301, 330-380.

Macroscaphites, Meek, 81 , mentioned,

73, 74, 76.

gigas, J. dc C. tiotverby, 81,

110,

Macrotherium, mentioned, 279, 388.

Macrotolagus, 467.

Maera, Leach, 426.

asper, Dana, 426.

confervieola, Stinqison, 425.

indicus, Dana, 426.

Krdyeri, Rathle, 426.

kiirgeusis, Gerstfcldt, 426.

Mastersii, Uaswell, 426.

Miersi, ]yrzemwwsl:i, 426.

pubescuns, Dana, 426.

Westwoodi, StelMng *, 426.

Major, C. I. Forsyth, on Fossil and

Eecent Lagomorpha, 433-520.

Malapterui'us, lateral sense-organs of,

195.

Mammal, t'ossorial, 488.

Mammalia, 504.

brain of, 277.

Manidae, 373, 391.

Manis, 279, 282-290.

javanica, 389.

Marcuinomys, Croizet, 437.

Marsupial, Hippocampal Region in,

50-58.

Marsupialia, 310-320.

brain in the, 280.

Marsupialia and certain Cheiroptera,

The Origin of the Corpus Callosum

in ; a Comparative Study of the

Hippocampal Kegiori of the Cere-

brum of, by G. Elliot Smith, 47-

69.

Megamoera Boeckii, Haswell.

426.

Mastersii, Haswell, 426.

snensis, Haswell, 426.

Megaphyllites obolus, ftnote 71.

sandalinus, ftnote 71.

Megapodius uicobariensis, mentioned,

231.

Megatherium, 282-29iS.

Melita, Leach, 425.

confervieola, Sthnjison, 425.

Gayi, Sicolet, 425.

insequistylis, Dana, 425.

tenuicornis, Stimpson, 425.

teaaicorim. Dana, 425.

Melphidippa serrata, Stehhiwj, 422.

spiuosus, Goes, 422.

Melphidippidae, 396 ; mentioned, 422

Meuidia, 184.

notata, 174.

Menobranchus, mentioned, 147.

Metamerism of the Lateral-line Sys-

tem, 148-156.

Metatarsus and Tarsus, Remarks on

the, of Lagomorphous Rodentia

(Forsyth Major), 504-510.

Metatheria, 281.

Metopa, mentioned. 35.

Microgale, 508.

Microprotopns, mentioned, 35.

Microtus, 477.

Micruropus, StehhiiKj *, 424.

Fixsenii, Dijhoii'sh-ii, 424.

glaber, Dijhoirsky, 424.

inflatus, Dyhowshtj, 424.

Klukii, Di/bowd-i/, 424.

littoralis, Dyhuu'slij, 424.

pachytus, DyhoivsTcy, 424.

perla, Dybowsl.y, 424.

puella, Dyboirdy, 424.

rugosus, Dybowsky, 424.

talitroidos, Dybowsky, 424.

vortex, DybuH'sky. 424.

Wahlii, Dybowsky, 424.

Miuiopterus, 48, 58, GO.

Schreibersii, 47.

Moera crassimaua, Mlers, 426.

viridis, Haswell, 426.

Molars, Lower, of Lagomorjjhous

Rodentia, 473.

Mole, brain of, 384.

Monodon, .500, 501 .

Monotrcmata, 277-2N0. 310 315.

brain of, 277-28<i.

Morphological N'aluc of the Lateralis

ICerve of Petromyzon, 178-179.

Morphology of the Facial (liauglion,

136-145.

of Jacobson'.s Anastomosis. 145-

148.

of the Ramus lateralis accesso-

rius, 166-178.

Moschus, 345-350, 387.

moschiferus, 345-350. 387.

Murida:, 473.

Mus, 497, 498, 508.

agrarius, ftnote 479.

decumanus, ftnote 227, 228,

ftnote 479.

mimitus, ftnote 479.

musc-ulus, ftnote 479.

rattus, ftnote 479.

sylvaticus, ftnote 479.

Musk-deer, brain of, 345.

Mylodon, 284, 298, 348.

Myogale, 508.

Myolatjus, Hensel, 434, 438, 449.

450, 464, 469, ftnote 484.

elsanvs, Forsyth Major, 457,

459.

Meyeri, Hensel, 451, 452.

sansainens'ts, Filhol, 451.

sardus, Hensel, 45(i.

Myopsida, 6.

Myrmecophaga, 282-292, 301-307.

jubata, 292.

Myrmecophagida% 285-31 13, 306,

390.

Myxine, mentioned, 189.

Nautilus, 73.

pompilius, 73.

Necturus, mentioned, 152, 191,

203.

Sense-organ in, 152.

Neobule, Hasnell. 397.

Neohela serrata, Stebbiny, 422.

Neoniphargus, Stebbmg *, 424.

puteanus, Monicz, 425.

Thomson i, Stehh'my *, 425.

Neossoptiles or Nestling-down, Dis-

tribution of the, 253-258.

Nephthya Cordieri, Audouhi, 526.

Nephthy id. Branching-system of, 525.

Nophthyida>, 524, 525, 534.

Nerf fiteriyo-dorsnl, Desmoulins &

Magendie, 16(i.

Nerve, Lateralis, of Petromyzon,

AForphological value of, 178-179.

Nervus accen.wrins Wcberi, in part,

Haller, ICd.

lateralis trigemiiii. Stannirig,

172.

latendis acccKSorius, Weber,

166.

Weberi, Goronowitscli, 166.

Nesolag'us, Forsyth Major*, 514;

mentioned, 505.

Netscheri, Schley. c|' Jeat., 514;

mentioned. 486, 499, 505,

.30(1, 517, 519, 520.

Nestling-down, Distribution of the

Neossoptiles or, 253-258.

Neumayria, -Nlkiiin, 89 ; mentioned,

76.

catenulata, Fischer, .S9.

Sicca pin iiiicornis. Heller, 412.

Ninox, 224, 264, 269, 271.

novie-zealandiif, Gm., 244—260,

271, 275.

INDEX.

547

Nijihargus, niciitionefl, 424, 425.

Moiiie/.i, ]Vr:einwwsJi'i, 425.

montaiuis, G. M. Thomson, 425.

Nomarthra, 301.

Notoryctes, 58, 364, 373.

typhlops, ftnote 59.

Nyctala, 271 ; mentioned, 226, 227,

264, 269.

Tengmalmi, Gm., 247, 255, 261,

271, 274.

Nyctalin», 264, 269.

Xyctea scandiaea, 241.

Xyctophilus, 48, 60, 62, 307, ftnote

391.

timoriensis, 47. 48.

Nyctornis, mentioned, 207.

Octopoda, 19.

( >ctopodid.T, 10.

Octopus, 1.

acnleatus, (TOrh., 20.

globosus, AppdVdf, 1 0 ; men-

tioned, 24.

Sranulatus, Lam., 19.

Jannarii, Stp., 19.

levis, Hotjle ?, 20.

niacropus, Risso, 20.

maculosus, Hoi/le, mentioned, 1 9.

microphthalmns, Ooo h-tch *, 20 :

mentioned, 24.

piotus (Bi-oclc), v.).

, var. fasciata, HoiiJe, 19 ;

mentioned, 24.

vulgaris. Lam.. 19.

Odontogammarus, Stehhiiif/ *, 427.

calcaratus, Di/hoivxkif, 427.

margaritaceus, Difhowshf, 427.

' Kcotraustcs, Waagen, 99 ; mentioned,

76.

crenatus, Bnir/uih-c, 9!), 113.

Oigopsida, 9.

Ommatogaramarus, Stffihin;/*, 427.

albinus, Di/ljoii'ski/. 427.

amcthystinus, Dyhowsl'i/, 427.

carneolus, Di/hoivsJri;, 427.

flavus. Di/howsJci;, 427.

Oniscus testudo, 396.

Onycliii, 9.

Onyehoteuthis, 6.

Banksii, Leach, 11.

Operculo-mandibular Canal of Fishe.s,

101-104.

Opisthocomus, mentioned, 2.5.3.

cri.status, 272.

Oppelia, mentioned, 10], 109.

steraspis, mentioned, 101.

SECOND SERIES, ZOOLOGY. — VOL. VII.

Oppelina", mentioned, 101, 109.

Orchestia, Leach, mentioned, 395,

397, 399, 400.

Deshaycsli, Audonin, 400.

gammarelhis, Pallas, mentioned,

402.

grillus, Bosc, 402.

liawuiensis, Dana, 402.

8ulensoni, StchhiiK/*, 400 ; men-

tioned, 431.

sylvkola, Dana, 402.

fiHiiix, Dana, mentioned, 402.

traskiana, mentioned, 398.

tucurauna. Frit: Midler, men-

tioned, 401.

OrchestiidEB, 2(>, 395, 397.

Orehestoidea, Ximlet, 397.

Organs of Fishes.

.Auditory, 194-199.

Lateral Sense-, 194-199.

Sense-organs, on the Lateral-

line Canals, 129-131.

Other Sense-organs belonging

to the Lateral-line System.

131.

Ornithorhynchus, 55, 50, 57, 322-

325 ; cerebrum of, 60.

OrycteropodidsE, 391.

Orycteropus, 279-.307.

Oryctolagus, 514, 515.

crassicaudatus, Geoffr.. 4S(), 490,

499,506, 514,518, 520.

cuniculns, Linn., 404, 466, 490,

515, 510, 518, 519.

Oryzoryctes, 508.

OsVesalianum in human carpus, 501.

Otus, mentioned, 226.

Ovis aries, 328.

Owls, a Contribution towards our

Knowledge of the Morphology of

the, by W. V. Pycraft. 223-275.

Owls-

Barn, 224-226.

Down-feathers of, 257.

Hawk-, 224.

Long-eared, 226.

Short-eared, 220.

Snowy, 224.

Tawny, 226.

Tengmalm's, 224, 226.

Ural, 224.

O.xynoticeras, A. Ifijatt, 85 ; men-

tioned, 76.

sp., 85, 111.

ralseolagus, 433, 440-443, 403, 464,

470-473, 477, 478, 484-4.S7, 510,

514, 515.

Haydeni, Leid., 443, 470-473,

477, 478, 510.

triplex, 443.

Palamedea cornuta, mentioned, ftnote

231.

Pallasca, Bate, 422.

baikali, Utehhitnj *, 422.

Brandtii, Di/hotnski/, 422.

cancelloides, GerMfeUlt, 422.

cancellus, Pallas, 422.

Dybowskii, Stehhiruj *, 422.

(ierstfeldtii, Di/howsli-tj, 422.

Orubii, Di/howski/, 422.

Kessleri, Dyhowsl-y, 422.

(piadrispinosn, Sars, 422.

lleisnerii, iJi/lioirskif, 422.

Pallium in Edentata, 324.

Paudion, 268.

Pangolins, 298, 370, 279.

Papio, 494.

Paraceradocns, Stchhini/ *, 426.

Miersii, Pf^fer, 420.

Paracommissural Bod}- in Edentata,

322.

Paracrangonyx, Sleliliiar/ *, 422.

compactus, Chiltun. 422.

Paramicruropus, Stehhiag *, 423.

Solskii, Dijhowsl-ii, 423.

Taozanowskii, Di/lioirshi/,

423.

Parapallasea, Stehbing *, 429.

Borowskii, Di/bowsJeg, 429.

Lagnwskii, DghowsJci/, 429.

Piizyllii, D.jhmvskii, 429.

" Paratheria,"' 279,381.

Pardalisea, Delia Valle, 38.

ahijssi, Delia Valle, 38.

Pardalisoidaj, 38.

Pardaliscoides, Stehhinq, 38.

tenellus, Stehhing, 38, 45.

Parbyale, Stehhing *, 26, 44, 397.

fasciger, Stehhing *, 26, 44.

Parkiusonia, Bagle, lOS; mentioned,

76.

Parkinsoni, J. Soiuerhif, 103.

Parorchestia, Stehhing *, 402 ; men-

tioned, 396, 397.

hawaiensis, Dana, 402.

recens, (r. M. Thomson, 402.

sylvicola, Dana, 402.

tenuis, Dana, 402.

Peltoceras, Waagen, 102 ; mentioned,

76.

76

518

INDEX.

I'elloeeras, sp., 102, 112.

Pelycodoid type, 472.

Pelycodus, 449, 472.

helveticus, Eiit., 449, .515.

Perameles, 51, 55, 56, 57, 58, 380;

cerebrum of, 66,

nasuta, 50, 51 ; coronal section

through the fore-brain of, 68 ;

hippocampus of, 50.

obesula, 508.

I'erca, mentioned, 147, 184.

Pereionotus, Bate 4' Westw., 414, 416.

Thomsoni, Stehbing*, 417; men-

tioned, 419, 432.

testudo, Montagu, mentioned,

417,418.

Perelonotvs, Delia Valle, 417.

Pereionotus, Stebbing, 417.

Perisphinctes, Waugen, 102 ; men-

tioned, 76.

Achilles, <rO,-Ugny, 102, 112.

Perissodactyla, 388.

Petromyzon, 185 ; mentioned, 205.

Lateralis nerve of, 148.

Morphological value of the

Lateralis nerve of, 178-179.

Phascolarctos, 56, 329-333, 510 ;

cerebrum of, t~'6.

cinereus, 57 ; brain of, 57 ;

sagittal section through part of

the anterior portion of the

mesial wall of the cerebral

hemisphere of, 68.

Phascolomys, ftnoto 485, 495.

Phliadida;, 396.

Phlias, G' !/('(•{», 414 ; mentioned, 417.

serratus, Overin, 417.

Photodilus hadius, mentioned, 272.

PhoxocephalidsB, 32.

Phreatogammarus, Stebbing *, 427.

fragilis, Chilton, 427.

Phylloeeras occultum, ftnote 72.

Phylogeny of the Lateral or Sensory

Canals, 187-194.

Picas, 513.

" Pichi-eiego," 358.

Pig, brain of, 345.

Pinacoceras, mentioned, h)().

humile, ftnote 72, 106.

insectum, ftnote 72, 106.

mvophorum, ftnote 72.

transiens, ftnoto 72.

Placentalia, 277.

Plakarthrium, CliiUon, 396.

Platyischnopus, mentioned, 35.

Platyodon, Bi-avard, 437.

Plesiadapis, 449, 470, 472.

Daubrei, Lem., 515.

Plesiogammarus, Stebbing *, 426.

Gerstaeckeri, Dijhowshy, 426.

Plumuloe, 256.

Podargus, 268.

Poekilogammarus, Stebbing *, 428.

araneolus, Dybowshy, 428.

orchestes, Uybotvsky, 428.

pictus, Dybowshy, 428.

talitrus, Dybowshy, 428.

Polypterus, mentioned, 146, 147,

171, 203.

Pontharpinia, Stebbing *, 32.

pinguis, Haswell, 33, 45.

Priodon, 282-284, 349-351, 374,

503.

giganteus, 502.

Prionotropidse, Zittel, 76, 104.

Prolagus, Pomel, 433-438, 448, 449,

451-462, 469, 471-478, 482-486,

499, 508, 509, 511 ; molars of,

446.

elsanus, Forsyth Major, 459,

460, 477.

loxodus, Gerv., 457.

Meyeri, Depe'ret, 451.

oeningensis, Koniij, 435, 450,

452, 453, 454, 455, 461-463,

471-477, 482, 483, 499, 507,

515-518, 520 ; deciduous

upper teeth of, 455, 456.

sansaniensis, Pomel, 450 ; men-

tioned, 438.

sardus, R. Wagner, 435, 453-

459, 472, 476, 483, 499, 505,

507, 515, 520.

, var. corsicanus, 458, 476,

477, 507, 517, 520.

(Myolagus), 460, 469.

Proteles, 335.

cristatus, 330.

Protopterus, 116 ; mentioned, 141,

146, 169, 173, 184,288.

annectens, mentioned, 146.

Prototheria, 310, 361.

Pterichthys, 120.

Pterolysis, read Pterylosis of the

Adult in Owls, 228.

Pteromys, 447, 497.

magnificus, 497.

melanotis. Gray, 519.

nitidus, Desm., 520.

volucella, 497.

Pteropus, 330, 342.

medius, 339.

Pteropus poliocephalus, 330.

Pteroti, 19.

Pterylography, 223.

Pterylosis of the Adult in Owls, 228 ;

of the Embryo, 254—256.

Pycraft, W. P., A Contribution

towards our Knowledge of the

Morphology of the Owls, 223-275.

Eabbit, 491, 511 ; brain of, 380.

Burrow, ftnote 488, 491.

Bush, ftnote 488.

European, ftnote 489.

Grey, 490.

Marsh, 491.

Rook, ftnote 490.

Wood, 491, 492.

Raia, 116, 184.

hatis, 184.

Ramus cutaneus quinti of Fishes,

T. J. Parher, 166, 172.

vcntrales, 151.

lateralis aecessorius, Weber,

structure and morphology of,

166-178.

trigemini, Weber, 166.

vagi, 151, 172.

opercularis facialis, 202.

profundus lateralis vagi, 180.

quartus s. lateralis nervi trige-

mini, Bensdorff, 166.

recurrcns facialis, Stannius, ]6fi.

trigemini et facialis, Stan-

nius, 166, 172.

superficialis lateralis vagi, 180.

Rana, mentioned, 201.

Anastomosis in, 14(i.

Roptilia, 288, 323.

Rhea, mentioned, 233, 273.

Ehynchocyon, 389.

Eodentia, 278-283, 502.

Remarks on the Metatarsus

and Tarsus of Lagomorphus

(Forsyth Major), 504-510.

Romerolagus, 513, 514.

Nelsoni, Merr., 441, 492, 514,

517, 520.

Salmo, 152, 180, 181.

Sancho, Stebbing *, 42, 45.

platynotus, Stebbing *, 42, 45.

Saroophyton, forms of, 524.

Sauropsida, 375.

Scaphites, Parhinson, 81 ; mentioned,

73, 74, 76.

sequalis, J. Sowevby, 82, 110.

INDEX.

549

Scaphites biiiodosus, A. Iloemer, 81,

110.

Scelidotherium, 298, 348.

Sceloglaus, 200 ; mentioned, 223,

224, 245, 204, 271.

albifaeies, Graij, 244, fig. 245 ;

mentioned, 223, 200, 271,

272.

aliico, 271.

uralense, 271.

Schloenbachia, Nemtunjr, 104 ; men-

tioned, 70.

Goodhalli, ./. Suwerh;/, 104.

Sciuropterus fuscocapillus, Blyth,

519.

volucella, 497.

xanthipes, Milne-Edw., 520.

Scops, mentioned, 224, 225, 244,

255, 200, 209, 271.

gill, Scop., 243 ; mentioned, 200,

271.

leucotis, Temm., 242; mentioned,

243, 244, 200, 271, 274, 275 ;

filoplume of, 258.

Scyllium, mentioned, 190.

embryos, cranial nerves of, 142.

Semnopithecus, 457.

moiispessulanus, 457.

Sense-organs of Fishes, 194-199.

Lateral, of Vertebrates and In-

vertebrates, 185-187.

On the Lateral-line Canals, 129-

131.

Sensory Canals in general, 120-122.

Phylogcny of, 187-194.

Eelation of, to the Skull, 131-133.

of Gadus morrhna, 122-129.

of Gadus virens, 121.

Sepia, 1. 3, 4.

aculeata, von Hasselt, 3.

officinalis, 4.

Rouxii, d'Orh., 4.

singalensis, Goodrich*, 3; men-

tioned, 4, 22.

aingaporensis, Pfeffcr, 3.

Sepiadarii, Stp., 3.

Sepiadarium Kochii, 8tp., 3.

Sepiarii, Sip., 3.

Sepiella inermis (v(tn Hasselt, MS.),

5.

Sepiola, 2.

Sepiolini, 2.

Sepioteuthis, 1, 5, 7.

Bluinvilliana, Fer., 5, 0.

indica, Goodrich *, 5; mentioned,

22.

Sepioteuthis mauritiana, Q. i5' G., 5,

0,7.

Auditory Sense-organs in, 152.

Sero]ida>, 390.

Serranus, mentioned, 152.

Sharks, mentioned, 193.

Sheep, brain of, 328-330.

Silurus, 119.

glanis, 107, 172.

Siphoneus, 488.

Siphonogorgia, 524, 527, 528, 534.

GodefFroyi, 524.

Siphonogorginfe, .52.5, 520, .527.

Siren, mentioned, 147.

Skull— The Bony Palate of theLago-

morphinsB (Forsyth Major), 485-

487.

Relation of the Sensory Canals

to the Skull, 131-133.

Sloths, 278-280.

Two-toed, 345.

Smith, G. Elliot, The Brain in the

Edentata, 277-394.

The Origin of the Corpus Cal-

losum : a Comparative Study

of the Hippocampal Region of

the Cerebrum of Marsupialia

and certain Cheiroptera, 47-

09.

Sonninia, lldijle, 98 ; mentioned, 76.

sp., 9S,\l3.

Spalax, 4SS.

Speotyto, mentioned, 224, 225, 227,

247, 248, 251, 253, 257, 259, 204,

270, 271, 274, 275.

Adult, down-feathers of, 257.

cunicularia, Molina, 249 ; men-

tioned, 253, 257, 271, 274,

275 ; plumule of, 257 ; pre-

penna of, 257 : filoplume of,

258.

cunicularia bypoga'a, 272.

Spongodes, 534, 5.30.

Sijualus, mentioned, 152.

Squamata, 391.

Steatornis, mentioned, 207, 208,

272.

Stebbing, Rev. Thos. R. R., Amphi-

poda from the Copenhagen Museum

and other Sources, Part I., 25-45 ;

Part II., 395-432.

Stegooephalidai, 30.

Sterjocephalus ahyssorum, Delia Valle,

31.

Stephanoeeras, \Vaa(jen, 101 ; men-

tioned, 70.

Stephanoeeras Banksii, J Sowerhy,

101.

Stephanoceratidse, Neumayr, emend.

Zittel, 70, 101.

Striges, mentioned, 207, 268.

Strigida;, mentioned, 225, 267, 268,

272.

Striginae, mentioned, 225.

Strix, mentioned, 224, 220.

aluco, 274.

bubo, Z(ii;i ., mentioned, 224, 225.

flammea, Linn., 251, 255; men-

tioned, 225, 254, 263, 260,

207, 272, 274, 275.

otus, mentioned, 225.

Structure and Morphology of the

Ramus lateralis accessorius, 100-

178.

Submammalia, 323.

Superficial Ophthalmic Trunk of

Fishes, 156-158.

Supra-orbital Canal of Fishes, 150-

158, 182.

Surnia, 209, 271.

ulula, Linn., 248, 271, 274.

Sus, 345.

Sylvilagus, 505, 513, 514.

artemisia", 491.

brasiliensis, Linn., ftnote 464 ;

480, 487, 489, ftnote 491,

499, 505, 500, 508, 514, 510,

518, 520.

palustris, 491, 493.

sp., 518.

sylvaticus, 491, 513, 514.

(Limnolagus) aquations, 514.

( — ■ — ) palustris, 514.

(Romerolagus) ]S^elsoni, Merr.,

480, 514.

(Tapeti) brasiliensis, 514.

Syrnia, raentioued, 220, 227.

ulula, mentioned, 231.

Syrniiua;, mentioned, 225, 226.

Syrnium, mentioned, 225, 220, 240,

264, 209.

aluco, Linn., 245 ; mentioned,

241, 247, 202, 274.

lapponicum, mentioned, 264.

perspicillatum, in</t., mentioned,

240, 204.

uraleuso, Fall., 247 : mentioned,

262, 204.

Talitrus, Latrtille, 397 ; mentioned,

395.

yrillus, Bosc, 402. ^

550

INDEX.

Talorchestia, Dmia, ;397 ; mentioned,

.395, 397, 399, 400.

Deshayesii, Audoitin, 400 ; men-

tioned, 430.

Deshayesi, Chcvreux, 400.

iiovae-hollaudia;, Stebhing*, 399 ;

mentioned 400, 431.

pravidactyla, IlaswelJ, men-

tioned, 399.

tridentata, Stehh'mg *, 398 ;

mentioned, 430.

Talpa, 377, 384, 498 ; cerebiu of, 60.

Tamandua, 282-293, 303-305.

tetradactyla, 282, 382.

Taonius, 1.

abyssicola, Goodrich*, 17; men-

tioned, 16, 24.

(Megaloeranchia) maximus,

Pfeffer, mentioned, 18.

Taonoteuthi, 12.

Tapeti, 511, 513,514.

hrasiliensis, 514.

Tarsins, 5(:t9.

Tarsus of Lagoraorphous lUidcntia,

llemarks on the (Forsyth Major),

504-510.

Tatusia, 279, 2S2-297.

novemcincta, 297.

Teleostean, 12U.

Tetrapoda, 499.

Theriodesmus phylarchus, ftnotc 496.

Thylacinus, 320.

Tillodonta, 392.

Tinamou, feathers of, 265.

Tinea, mentioned, 147.

Tissotia, Boiivillr, 90 ; mentioned,

76.

Ewaldi, .■. B,t,f!, 90, 111.

Titanomys, H. v. Meyer, 436 ; men-

tioned, 433-435, 437, 438, 440,

446-453, 461, 462, 463, 471-482,

510, 511; teeth of. 484, 486,

493.

Fontannesi, Dtperet, 444 ; men-

tioned, 435, 436, 447, 448,

472-482, 507, 515-520 ; upper

teeth of, 462.

oeningensis, H. v. Meyer. 460.

«/v7o';H«,Gervais, 430; mentioned,

437, 438, 439, 475.

visenovicQsis, //. v. Meyer, 436 :

mentioned, 435, 437-448,

472-482, 484,486,511,516-

520 ; mandibnlar teeth of,

443.

( Lagodus), 446.

Tolai, 511.

Tolypeutes, 282-284, 298, 303, 308,

349.

tricinctus, Garrod, 308.

Torpedo, 187; mentioned, 190.

Trichomycterus, 170, 172.

Trichosurus vulpecula, 57.

Horizontal Section through part

of the anterior portion of the

mesial wall of the cerebral

hemisphere of, 68.

Trigemino-faoial Ganglionic Complex,

133-136.

Trigla, mentioned, 202.

Trunin, Bucoa], 158-161.

Hyomandibular, 161-164.

Lateralis, 164-166.

Superficial Ophthalmic, 156-

158.

Tubulidentata, 279, .391.

Turrilites, Lamarck; 83 ; mentioned,

73, 74, 76, 84.

Mantelli, »%aj-jo«, 83; mentioned,

111.

tuberculatus, Bosc, 83; men-

tioned, 84. 111.

(Heteroceras)polyplocus,iJo«JH€r,

84, 111.

Unguicnlata, 385-388.

Ungulata, 277-280, 344, 385, 386,

387.

Urodela, 496.

Urothoc, Has well, 32.

pinyuh, Has well, 33.

irrostrata ?, Delia Valle, 33.

Ursus arctos, 508.

Ventral surface of Cerebrum in Eden-

tata, 286.

Verania sicula, mentioned, 17.

Vertebrates and Invertebrates, Lateral

Sense-organs of, 185-187.

Xonarthra, 278, 390, 391.

Xenia, .522.

Xeniidffi, 522, 523.

Xenurus, 282-298, 320.

unicinctus, 308.

Ziphius, 500.

oavirostris, .500, .501.

(Hypcroodon), 500, 501.

Zoantharian Zooids, 534.

Zooids. Anatomy of the, .5.33.

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