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-2 

i 


1 



A MANUAL 



OF THE 



ANATOMY OF VERTEBRATED ANIMALS. 



A MANUAIj 

MOMY OF VEETEBMTED 

ANIMALS..^^, ...... 

aOMAS H. HUXLEY, LL.D., F.B.S. 




LONDON: 
. CHURCHILL, NEW BURLINGTON STREET. 
187L 









UMCDOX: raOfTED BT WILLIAM CLOWES AKD SONS, STAlt?OIU» STREPT 

AJCO CHiL&»0 CBOSS. 



Ht)e 



PBEFACE. 



The present work is intended to provide students of com- 
parative anatomy with a condensed statement of the most 
important facts relating to the structure of vertebrated 
animals, which have hitherto been ascertained. Except in 
a very few cases, I have intentionally abstained from bur- 
dening the text with references ; and, therefore, the reader, 
while he is jnstly entitled to hold me responsible for any 
errors he may detect, will do well to give me no credit for 
what may seem original, unless his knowledge is sufficient 
to render him a competent judge on that head. 

About two-thirds of the illustrations are original, the 
rest * are copied from figures given by Agassiz, Bischoff, 
Burmeister, Busch, Cams, Duges, Flower, Gegenbaur, 
Hyrtl, Yon Meyer, Miiller, Pander and D' Alton, Parker, 
Quatref ages, and Traquair. 

A considerable portion of the book has been in type for 

* Namely, Figures 1, 6, 10, 11, 12, 13, 15, 18, 23, 26, 28, 29, 30, 31, 
36, 39, 41, 42, 46, 50, 51, 54, 55, 56, 57, 58, 59, 60, 61, 75, 79, 82, 101, 
107, 108, 109, 110. 



VI PREFACE. 

some years; and this circumstance must be my excuse 
for appearing to ignore the views of several valued contem- 
poraries. I refer more especially to those contained in 
recently published works of Professors Flower and Gegen- 
baur. 

London, September j 1871. 



CONTENTS. 



-•- 



CHAPTER I. 

PAOB 

A Greneral View of the Organization of the Vertebrata — the 
Vertebrate Skeleton 1 

CHAPTER II. 

The Muscles and the Viscera — ^A Greneral View of the Organiza- 
tion of the Vertebrata 45 

CHAPTER III. 
The Provinces of the Vertebrata — The Class Pisces . . .112 

CHAPTER IV. 
The Class Amphibia. 172 

CHAPTER V. 
The Classification and the Osteology of the Reptilia . . . 193 

CHAPTER VI. 
The Classification and the Osteology of Birds .... 272 

CHAPTER VII. 
The Muscles and the Viscera of the Sauropsida .... 299 

CHAPTER VIII. 
The Classification and Organization of the Mammalia . . . 319 




9' 



'EOJEBRATED ANU 
f 



CHAPTER I. 



, nbollf J 



Tim Distinclive Chmactm-ti of the Verlebratn.—T^t^ Ferte-J 
lia are diBtinguialiecl from all other aniraala by the ci 
mce that a tranaverBe ajid vertical aectioii of the body 
hibita two cavities, completely sepHfated from one another 
& partition. The dura&l cavity contains the cei'ebro -spinal 
rvous system; the ventral, the alimentary canul, the 
art, and, ueually, a double chain of ganglia, which p 
der the name of the ■' sympathetic." It ia probabla<J 
ftt this sympathetic nervous system represents, 
' partiully, the principal nervous system of the Am. 
d MoUvMea. And, in any case, the central parts 
e cerehro- spinal nervous system, viz. the brain and the I 
inal cord, would appear to be unrepresented among 1 
pQTertebrated animals. For these structures are tJie results 
■-of the metamorphosis of a part of the primitive epidermic 
Ewvering of the germ, and only acquire their ultimate 
oaition, in the interior of the dorsal tube, by the develop- 
ent and union of outgrowths of the blastoderm, which 
» not formed in the InverUhrata.* 

» pMsible thst an exoep- tnin resemhlnnee lo a vertetunl 



the Ascidim 



The tolls I 



pliarynx a. 
in Amphl:<^ 



VEfeTEBRATED 

Again, is the partitioii betweShlttie cerebm -spinal and 
visceral tubea, eert!ain structuira, wUiA are not repreeented. 
in invert«brated animals, are contaJhed. During the em- 
bryonic condition of all vertehrateB, the centre of the parti- 
tion is occupied by on elongated, cellular^cvlindroidal masa, 
— the notochord, or chorda dwmlis. An Jfflis Structure p.er- 
eiirtiB throughout Life in some Vertebrata ; but, in moet, i 
more or leaa completely replaced by a jointed',. partly fl.br 
and cartilf^inous, and partly bony, verlebrnl coluTia 

In all Veriebraia, that part of the waJl of the v: 
which liei at the sidea of, and immediatelr h 
month, exhibits, at a certain stage of embryonic dS^lop-l 
ment, a series of thickenings, parallel with c 
and transverse to the axis of the body, which may be fivel 
or mure in number, and are termed the visceral arches.) 
The intervals between these arches become clefts, which' 
place the pharyngeal cavity, tempoi-arily or permanently,) 
in communication with the exterior. Nothing correspond- ■ 
ing with these arches and clefts is known in the JiMjcrie- . 

A Tertebi'uted animal may be devoid of articulated limba,. 
and it never possesses more than two pairs. These 
always provided with an internal skeleton, to which tha 
muscles moving the limbs are attached. The limbs of 
invertebrated animals are commonly more numerous, and 
their skeleton is always entemal. 

When invertebrated animals are provided with masti- 
catory organs, the latter are either hard productions of the 
alimentary mucous membrane, or are modified limbs. Ver- 
tebrated animals also commonly possess hard production^ 
of the alimentary mucous membrane in the form of teeth ; 
hat their jawH are always parts of the walls of the porietes. 
of the head, and have nothing to do with limbs. 

All vertebrated animals have a complete vascular system. 
In the thorax and abdomen, in place of a single p^- 
vieceral cavity in communication with the vascular system, 
and serving aa a blood-sinns, there are one or more si 
These invest the principal viscera, and may or 



I ha 



f THE VKETEBEATA. 

not communicate with tlie exterior — recalling, in the lal 
case, the atrial cavities of Mvlliuea. 

In all Vertebrata, except Amphioxiu, there is 
valvular heart, and all possesB a hepntic peiHal gyetem; the 
blood of the alimentary canal never facing whoUj returned 
directly to the heart by the ordinary veins, but being 
or less completely collected into a trank — the portal 
'hich ramifies through and supplies the liver. 

The Developmeiii of the Vertebrata.— The ova of Vertebri 
have the same primary compoBition aa those of other animaL^ 
conaisting of a germiiutl oegicle, containing one or n 
gaimnal spots, and included within a viteUan, upon 
amount of which the very variable size of the vertebrate 
ovum chiefly dei)endB. The vitellua is surrounded by a 
viteUine meiiArane, and tliia may receive additional inveat- 
menta in the form of layers of aVmmen, and of an outer, 
coriaceous, or calcified ehell. 

The ipermaioxoa are always actively mobile, an 
sijme nixe and exceptional cases, are developed in distini 
individuals from those which produce ova. 

Impregnation may take place, either subsequently to 
extrusion of the egg, when, of course, the whole developmi 
of the young goes on outride the body of the oviparotu- 
. ; or it may occur before the eitruBion of the egg. 
latter case, the development of the egg in the interior 
body may go no further than the formation of a patch 
ary tissue ; as in birds, where the so-called cicutricuia, 
id," which is observable in the new-laid egg, is of this 
Or, the development of theyoung maybe completed 
he egg remains in the interior of the body of the 
but quite free and unconnected with it ; as in those 
Vertebrates which are termed ovomioiparima. Or, the young 
laay receive nourishment from its viviparova parent, before 
Inrth, by the close apposition of certain vascular appendages 
of it« body to the walls of the cavity in which it undergoes 
its development. 
ThtyrasfulBr appeudages in question constitute the d 



1 

the 

% 

:any ^H 

the ^H 

rate ^\ 
7 a 

ini^^H 

M 

■Eg- I 



!■ VBRTEBE4TED 

part of what ia called the p^aeenia, and may be developed from 
the umbilical vesicle (as in Mustelua amon^ Shares), or front 
the HJlantoiB and chorion (as in moat mammalB), At birth. 
they may be either simply detached from the snbatance of 
the parental ortTtniam, or a part of the latter may be thrown 
off along wit]i them and replaced by a new growth. 




the highert vertebratea, the dependouce of tlie young upon 
the parent for nutrition does not cease even at birth ; but 
certain cutaneous glands secrete a fluid called milk, upon 
which the young is fed for a longer or shorter time. 

When development takes place outside the body, it may 

tie independent of parental aid, aa in oidinary fiahea; but. 

^bg some reptiles and in most birds, the parent supplies 



HE VERTE6BA.TA. 



rthe amoant of heat, in excess of the ordinary temperati 
of the air, which is required, from its own body, by 
prgcesB of inetibation. 
TLe first step in the development of the embryo is 
division of the TiteUine substance into cleaBage-maamt 
which there arc at first two, then four, then eight, and 
on. The gerininul vesicle is no longer seen, but ea, 
cleava.ge-mass contains a niicleiiB. The cleavage- 
eventually become very small, and are called enibryo-celU, 
as the body of the embryo is built np out of thi 
process of yelk-division may be either complete or partU 
In the formei- caee, it, from the firBt, affects the whole^ 
yelk T in the latter, it commences in part of the yelk, anfl 
gradnally extends to the rest. The blasiodenri, or em- 
biyogenic tissue in which it results, very early eihibits 
two distingiiishable strata — -an imier, the so-called 

(hypohtoit), which givea rise to the epithelium of 
alimentary tract; and an outer, the eeroua etratum 
tibjastj, from which the epidermis and the cerebro-spinal 
evolved. Between these appeals the 
niedieite atrattim (laeaoblaul) , which gives rise to all the 
iicturea (save the brain and spinal maiTow) which, in the 
included between the epidermis of the integu- 
ment and the epithelium of the aUmentary tract and its 
appendages. 

A lineal' depression, the primitive groove (Fig. 2, A, e), 
makes it^ appearance on the surface of the btaBtodurm, and 
the substance of the mesoblast along each side of tbiG groofe 
grows up, carrying with it the superjacent epiblast. ThoB 
are produced the two doraal tamtme, the free edges of which 
arch over towards one another, and eventually unite, so as 
to convertthe primitive groove into the cerebro -spinal canal. 
The portion of the epiblaat which lines this, cut off from 
structure of 
brain, or EB,eephalon, in the region c 




I 



the spinal cord, < 



Myelon 



1 the 



region 



of the 



WuCest oi the epiblaat is conveiled into the epidermis. 



spin 



The part of the blastoderm which lies eitemal to the dot- 
Bal lamiuffi forma the ventral lamiwe ; and these bend duwn- 
wards and inwards, at a, ahort distance on either side of the 
lioraa! tube, to become the walla of a ventral, or visceral, 
tube. The ventral laminsB carry the epiblaat on their outer 
Burfaces, and the hypoblast on their inner surfaces, and thus, 
in most cases, tend, to coustriut off the central from the 
penpheral portions of the blaatuderm. The latter, extend- 
ing over the yelk, inclosea it in a kind of ba^. This bag is 
the first-formed and the most constant of the temporarj, 
or fiBtal, appendages of the young vertebrate, the wiabUii 

While these changes are occurring, the mesoblast spli 
throughout the regions of the thorax and abdomen, fi 
its ventral margin, nearly up to the tiotoekord (which has, 
been developed, in the meanwhile, by histological differen- 
tiation of the aual indifferent tissue, immediately under 
the floor of the primitive groove), into two latneUm. One ot' 
these, the vieceral laineUa, remains closely adherent to the 
hypoblast, forming with it the spiaweftnopfeure, and eventa- 
ally becomes the proper wall of the enteric canal; while 
the other, the 'parietal lamella, follows the epiblast, forming 
with it the aoniatnpleare, which is converted into the parietes 
of the thorax and abdomen. The point of the middle line 
of the abdomen at which the somatopleures eventually unite, 
is the umbilicuB. 

The walls of the cavity formed by the splitting of thi 
ventral larainfe acquire an epithelial lining, and become the 
great pleuroperitoneal serous membranes. 

Tlie Feelal Ajipendagei of the Vertebraia. — At its outer 
mai^in, that part of the somatopleure which is to be 
converted into the thoracic and abdominal wall of the 
embryo, grows up anteriorly, posteriorly, and laterally, 
ffver the body of the embryo. The free margins of 
this fold gradually approach one another, and, ulti- 
mately uniting, the inner layer of the fold beoorosB 
converted into a sac filled with a clear fluid, the Am- 
. irJule the outer layer either disappears, or coa^ 



I 



« 



S THE ANATOMY OF VEETBBRATED ANIMALS. 

leacea with the ritelline Diembrane, to form the ( 

I Fig. 3). 

Fig. 3. 





Fig. 3.— Later ilagei of the development of the body of a Fowl than 
those represented Id Fig. 2.— E, embryo at the thin! day of incuba- 
tion; g, heart; 'i, eye; i', ear; {, viacerul arches and clefts; /, n, 
imterfor and posterior foldi of the amnitm which have not yet united 
over the body ; 1, 2, 3, Brst, secoud, and third cerebral vesiclea ; la, 
veiieleof the third ventricle.— P, embryo Bt the fifth day uf Incuba- 
tion. The letters as betbre, except k, d, rudiments of the anterior 
and posterior extremities; ^m, amnion ; J/J (the ailantois, hanging 
down from its.pediolo) ; Um, umbilical vesicle.— G, uudcr-vlew of 
the head of the foregoing, the first visceral arch being cut away. 

Thus the atmuon incloBCB the body of the embryo, but 
e umbilical BEtc. At jaoet, aa the constricted ne 



THE VISCERAL AKUHES AND Cl^FTH. 

which uniteH the umbilical sac with the cavity of the futui 
iutestiite. becomes narrowed and elongated into the w 
dw:t, and as the aac iteelf diminishei in relative aize, t 
amnion, increasing in absolute and relative dimensions, ajid>^ 
becoming distended with fluid, is reflected over it (Pig. 1). 

A third fcetal appends^, the AlUmtoig, commences as a 
single, or donhle, outgrowth from the imder-surface of 
the mesoblast, behind the alimentary tract ; bv 
takes the form of a vesicle, and receives the ducts of 
tto printordial kidneys, or Wolffian bodiet. It is supplied 
with blood by two arteries, called kypogattrie, which spring J 
from the aorta ; and it varies very much in its development J 
It may become so large as to invest all the reist of the ■] 
embryo, in the respiratory, or nntritive, prooeaaes of whicli I 
it then takes an important share. 

The splitting of the ventral lamince, and the format I 
tion of a pleuroperitoneal cavity, appear to take plac 
all Verlebraia. Usually, there is a more or less distincbfl 
umbilical sac ; but in fishes and Amphibia there 
umuion ; and the aUantoia, if it is developed at all, remain, 
very small in these two groups. 

Reptiles, birds, and mammals have all these fcetal appei 
dages. At birth, or when the egg is hatched, the a 
burets and is thrown off, mid so much of the allantois a 
lies outside the walla of the body, is similarly eruviated ; 
but that part of it which is situated within the body is veiy 
generaJly converted, behind and below, inta the urinaiy 
bladder, and, in front and above, into a ligamentous cord, 
the uraekvt, which connects the bladder with the front w 
of the abdomen. The umbilical vesicle may either be ci 
off, or taken into the interior of the body and graduallyB 
absorbed. 

The majority of the visceral clefts of fishes and of many 1 
Amphibia remain open throughout life; and the visceral a 
arches of all fishes (eicept J-inpAiouMts), and of all Amphibia, M 
throw out filamentous or lamellar procoases, which r 
branches from the aortic arches, and, as (tranchiir, subservM 



10 THE ANATOMY OP TBBTEBR4TED ANIMALS. 

reHpinition. In other Verf^brata ail the TiBceral oletto 
become cloBed and, with the frequent exception of the fiiat, 
obliterated i and no brunehite are developed upon anj of 
the visceral archee. 

In all vertebrated animals, a system of relatively, or abeo- 
lutely, hard parts affords protection, or support, to the softer 
tisaues of the body. These, according as they are aituated 
upon the surface of the body, or are deoper-Beat«d, are called 
eaioakehton, or endoakekton. 

The Vertebrate Endoakeleton,. — This consists of connective 
tissue, to which cai-tilage and bone may be added in various 
proportions ; together with tbe tissue of the notoehord and 
its sheath, which cannot be classed under either of these 
heads. The endoskeleton is distinguishable into two inde- 
pendent portions — the one aicial, or belonging to the head 
and trunk ; the otber, aj^endicular, to the limbs. 

The axial tndoekeleton usually consists of two aystemH o£ 
skeletal parts, the «pinaZ system, and the cranial eygtem, the 
distinction between which arises in the following way in the 
higher Yertebrata. 

The primitive groove is, at first, a simple straight depres- 
sion, of equal diameter throughout { but, as its sides rise, and 
the dorsal lajoinie gradually close over (this process com- 
mencing in the anterior moiety of their length, in the 
future cephalic region), the one part becomes wider than 
the other, and indicates the cephalic region (Fig. 4, A). The 
notoehord, which underlies the groove, terminates in apoint, 
at a little distance behind the anterior end of the cephalic 
enlargement, and indeed under the median of three dilata- 
tions which it presents. So much of the floor of the enlsu'ge- 
ment as lies in front of the end of the notoehord, bends 
down at right angles to the rest ; so that the anterior en- 
largement, or anteriw cerebral venoU, as it is now called, lies 
in front of the end of the notoehord ; the median enlarge. 
ment, or the iniMle cerebral vesicle, above its extremity ; 
and the hinder enlargement, or the posterior cerebral ' 
vencle, behind that extremity iFig. 4, D and E). Theunderi 



r 



THE PaOTOr ENTEBBE. 11 

aurfaue of the anterior vesicle lies in a kind of pit, in front 
of, and rather below, the apei of the notocliord, uud the 
pituifaty gland ia developed in connection with it. From 
the oppoaite upper aurface of the same veaiole the pineal 
gland ia evolved, and the part of the anterior cerebral vesicle 
in connection with which these remarkable bodies arise, 
ia the future third ventricle. 

Behind, the poaterior cerebral vesicle pasaea into the 
primitively tnbnlar spinal cord (Fig. 4, Aj, Where it doea 
so, the head ends, and the spinal column begins ; but no 
line of demarcation ia, at firat, visible between these two, 
the indifferent tissues which enaheatb the notochord pass- 
ing, without interruption, from one region to the other, and 
y retaining tbe anme character tlironghout. 
< The fii'st esaential differentiation between the akull and 
vertebral column ia effected by the appearance of the 
overtehrw. At regular intervals, commeneiag at the 
anterior part of the cervical region, and gradually estending 
backwarda, the indifferent tiaaue on each side of the 
notochord imdergoea a histological change, and gives rise 
to more opaque quadrate masaes. on opposite sides of tbe 
notochord (Fig. 2, B, C). Bach pair of these gradually 
unite above and below that structure, and send arched pro- 
longations into the walla of the spinal canal, ao as to con- 
stitute a protovertebra. 

So protovertebne appear in the floor of the skull, bo i| 
thai, even in this early stage, a. cleur distinction is drawn •! 
between the akuU and the spinal colui 

Tiie Spiiutl System. — The protovertebraa consiat at first I 
ijf mere indifferent tissue ; and it is by a procesa of histo- I 
logical differentiation within the protovertebral ma 
that, from its deeper parts, one of the ^lud ganglia 
a caTtHagiiunu vertebral eentrum, — from its superficial layer, I 
K tegment of the dorgal invtcles, are prudnced. 

Eondtification extends upwards into the walla of t 
1 tube, to produce the iieural arch and gpine 
bra; and, outwards. Into thu wall of the thoracic a 



OSSIFICATION OF THE YEBTEBBJE. 13 

organs ; dj the infundibalum ; «, the pineal gland ; c, protoverte- 
brae ; /i, notochord ; 1, 2, 3, 4, 5, visceral arches ; V, VII, VIII, the 
trigeminal, portio dura, and ninth and tenth pairs of cranial nerves ; k, 
the nasal process ; /, the maxillary process ; x^ the first visceral cleft. 
A, B, upper and under views of the head of a Chick at the end of the 
second day, C, side-view at the third day. D, side-view at seventy- 
five hours. E, side-view of the head of a Chick at the fifth day, 
which has been subjected to slight pressure. F, head of a Chick at 
the sixth day, viewed from below. 

abdominal part of the ventral tube, to give rise to the trans^ 
verse processes and Hhs. In fishes, the latter remain distinct 
and separate from one another, at their distal ends ; but, in 
most rcptnes, in birds, and in mammals, the ends of some 
of the anterior ribs, on both sides, unite together, and then 
the united parts coalesce in the middle line to form a median 
subthoraeic cartUage — ^the sterntmi. 

When ossification sets in, the centra of the vertebrae are 
usually ossified, in great measure, from ringlike deposits 
which closely invest the notochord; the arches, from two 
lateral deposits, which may extend more or less into the 
centrum. The vertebral and the sternal portions of a rib 
may each have a separate ossifio centre, and become distinct 
bones ; or the sternal parts may remain always cartilagin- 
ous. The sternum itself is variously ossified. 

Between the completely ossified condition of flie verte- 
bral column and its earliest state, there are a multitude of 
gradations, most of which are more or less completely 
realised in the adult condition of certain verfcebrated animals. 
The vertebral column may be represented by nothing but 
a notochord with a structureless, or more or less fibrous, 
or cartilaginous sheath, with or without rudiments of carti- 
laginous arches a7id ribs. Or there may be bony rings, or en- 
sheathing ossifications, in its walls ; or it may have ossified 
neural arches and ribs only, without cartilaginous or osseous 
centra. The vertebrae may be completely ossified, with very 
deeply biconcave bodies, the notochord remaining persistent 
in the doubly conical intervertebral substance ; or, ossifica- 
tion may extend, so as to render the centrum concave on 
one surface and convex on the other, or even, convex «iXj eakSi)cL 
end. 



U THE ANATOMY or ^ 

Vertelira which have centra concave at each end have 
been conveniently termed amphieteloua ; those witii a cavity 
in front and a oonyexity behind, pToccebyas; where the 
position of the concavity and convexity is reveraed, they are 
opUfthocaloue. 

In the Mammalia, the centra of the vertebrte are nanally 
flat at ea«h end, the terminal faces being discoidal ^iphygeg, 
developed from centres of osaification distinct from that of 
the centmm itself. 

The centra of the vertebrie may be united together by 
aynovial joints, or by iigamentoos fibres — the intervertebral 
ligamenU. The arches are connected by ligaments, and 
generally, in addition, by orerlapping articular prooesBea 
called zT/gapophyseg, or oblique processes. 

In a great many Vertebrata, the first ajid second cervical- 
or ailag and luni, vertebne undergo a singular change; the 
central ossification of the body of the atlas not coalescing 
with its lateral and inferior ossifications, but either persist- 
ing aa a distinct oa odontoide'Wm,, or ankylosing with the 
body of the aids, and becoming the so-called odimfoid proceag 
of this vertebra. 

In Tertebrata with well- developed hind hmbs, one or 
more vertebrte, situated at the posterior part of the trunk, 
usually become peculiarly modified, and give I'ise to a 
eacrvmi, with which the pelvic arch is connected by the 
intermediation of espanded and ankylosed ribs. In front 
of the saonim the vertebra are artificially classed as oervieal, 
dorgal, and lumbar. The first vertebra, the ribs of which 
are connected with the sternum, is dtjreal, and all those 
which lie behind it, and have distinct ribs, are dorsal. 
Tertebrp! without distinct ribs, between the last dorsal and 
the sacrum, are Iwniar. TertebrtB, with or without ribs, in 
front of tbe first dorsal are cervical. 

The vertebriB which lie behind the sacrum are caitdal or 
eoeeygeal. Very frequently, downward processes of these 
vertebrte inclose the backward continuation of tbe aorta, 
and may be separately ossified as suicaudal, or chemin, 
bones- 



A SCSMENT OF THE BEELETOV. 

A tolei'ably complete aegment of the Bpinal skeleton u 
be staJied in the anterior part of the thotiii of a urtx 
[Fig'. 5). ItpveaeiitBaprocceIoiiBvertebraleeiiir«m(C),u 
irith which bj the newrooeniral mdvo'e is the n«uraZ ardAfl 
which risea into the neural apine {If.8.). Two proceaBea, thf 
pretygapophyaea {Z), extend fi-om the front part of the arebjl 
and have flat articular aurfacea turned dorsally. Two others 
of similar form, bat having their articular surfaces tiimed 
ventrally, proceed fi-om the poaterior fiice of the neural 
arch, and are the poalzygnpophijieg {Z'). By these, which are 




Fig. S. — A fegment of llie emloski 
of Ihe body of a Crocodile.— C, thf 
JV. S.. theneural (pine ; Z. Ihe pre 



jhytaa; T. 

onlum of the rib {() ; Cp.t, that whicli orticulati 

of the rib(C);); Kr, [lie ossified vertebral ri 

I St, an HTtiflciBli; separated Begrnent ot ihe stei 



thoracic region's 
OP body of the vertebral H 
rsis ; iP, the pottzygapo- 
'ith (he tubcr- 



ften called oblique, or articular, proceeaes, the vertebMifl 
iculatee with the corresponding prooeaaeB of its pr»J 
ecessor or succeaaor in the seriei*. The tfammenf pro>V 
wo on each side, one superior and one inferior^ 
! farmer {TX) articulates with the tubercufunt of th<M 
', the latter {GpX\ with its cajiidihcni, Tliey may, thera 
I, be called captiufar and iufceitniior irajisi'erse pracmaa 
s/S^Ajt £ach rib ia divided by an ai'ticulution u 



16 THE ANATOMY OP YBRTEBfiATED ANIMALS, 

a vertebral [V.r] and a eternal [St.r) part. The former re- 
maisB UBoBsified for a considerable dietance at its diatal 
end {V.r'); tbe latter is more or leas converted, into car- 
tilage bone. The proximal end of the vertehnJ. rib bifnr- 
cat«a into a tubereuhtm {t) and a capitiibim |Cp). The diatal 
end of the sternal rib unites with the more or lese oesi- 
fled but unsegmented cartilage, which forms the Btemum 
(St). A cartilaginoiis,or partly oBsified, uncinafe^ocess {Pm] 
projects from the poateriov edge of the vertebral rib, over 
the intercoBtal epa4.'e. The student will find it convenient 
to familiarise himself with the conception of such a epinfll 
Begment aa this, aa a type, and to consider the modifica- 
tiona hereafter described with reference to it. 

In the majority of the Veiiebrain, the caudal vertebrtt 
gradually diaiinisli in size towards the extremity of the 
body, and become reduced, by the non-development of o 
oiiB processes or arches, to mere centra. But, inmany fial 
which possess well-ossified tmnk vert«bne, no distinct 
centra are developed at the extremity of the caudal i-e^on, 
and the notochord, invested in a more or less thickened, 
fibrous, or cartilaginous sheath, persists. Notwithstanding 
this embryonic condition of the axis of the tail, the superior 
and inferior arches, and the interspinous bones, may be 
completely formed in cartilage or bone. 

Whatever the condition of the extreme end of the spine 
of a fish, it occasionally retains the a-ime diiection as tlLe 
trunk part, but is far more generally bent up, so aato form 
an obtuse angle with the latter. In the former Ci 
tremity of the spine divides the caudal fln-raya into two 
nearly equal moieties, an upper and a lower, and the fish is 
said to be diphycerced (Fig. 6, A). In the latter ca.Be, thv 
upper division of the caudal fin-rays is much smaller than 
the lower, and the fish is helerocercal (Fig. 6, B, C). 

In most oaacouB fishes the hypural bones which support 
the fin-rays of the inferior division become much expanded, 
and either remain sepai'ate, or coalesce into a wed 
shaped, nearly symmetrical bone, which becomes aukylosed 
with the last ossified vertebral centrum. The inferior fin- 



IS THE ANATOMY OF YEKTEBKATED ANIMALS. 

rajB are now disposed in ancli a maimer as to give the tail 
an appearance of symmetry with respect to the axis of the 
body, and such fishes have been called hojnocercal. Of theae 
homooercal fish, some (aa the Salmon, Fig. 6) have the 
notochord unoasified, and protected only by bony plates 
developed at ite sides. In others (ae the Stickleback, 
Perch, &c.), the aheath of the notochord becomes completely 
ossified and united with the centrum of the laat vertebra, 
which then appears to be prolonged into a bony wostyle. 

The Cranial System. — Aa has been stated, no protover- 
tebrse appear on the floor of the skull ; nor is there any 




Fig. T. — The cartiUginous cranium of a Fowl at the sixth daj' of in- 
Cabatioa, viewed ffom below.— i", the pituitary space ; ir, ihe tra- 
betula, uniting in ftont, In the bifurcated elhrnovomerine plate ; Qh, 
the quadrate cartJIage; Sc, the semicicculor canals ; Co, the cochlea; 
A, Ihe notochord imbedded in the basilar plate. 

cranium, nor any developmental stage of a ci-anium, in 
which separate cartilaginous centres are known to occur in 
this region. 

On the contrary, when chondrification takes place, it 
extends continuously forward, on each side of the notochord, 
and usually invests the anterior termination of that body, 
mote or less completely, as a basilar plate. 



THE CBANIAL SKELETON. 19 

The basilar plate does not extend under the floor of the 
pituitary fossa, but the cartilage is continued forwards on 
each side of this, in the form of two bars, the traheculce 
cranii. In front of the fossa, the trabeculse reunite and end 
in a broad plate, usually bifurcated in the middle line — ^the 
ethmovomerine plate. 

On each side of the posterior boundary of the skull, 
the basilar cartilage grows upwards, and meets with its 
fellow in the middle Hne, thus circumscribing the occipital 
foramen, and furnishing the only cartilaginous part of the 
roof of the skuU; for any cartilaginous upgrowths which 
may be developed in the more anterior parts of the skull 
do not ordinarily reach its roof, but leave a wide, merely 
membranous space, or fontanelle, over the greater part of 
the brain. 

Before the skull has attained this condition, the organs 
of the three higher senses have made their appearance in 
pairs at its sides; the olfactory being most anterior, the 
ocular next, the auditory posterior (Fig. 4). 

Each of these organs is, primitively, an involution, or sac, 
of the integument ; and each acquires a particular skeleton, 
which, in the case of the nose, is furnished by the ethmo- 
vomerine part of the skull ; while, in that of the eyes, it 
appertains to the organ, is fibrous, cartilaginous, or osse- 
ous, and remains distinct from the skull. In the case of the 
ear, it is cartilaginous, and eventually osseous : whether 
primitively distinct or not, it early forms one mass with the 
skull, immediately in front of the occipital arch, and often 
constitutes a very important part of the walls of the fully- 
formed cranium. 

The ethmovomerine cartilages spread over the nasal 
sacs, roof them in, cover them externally, and send down 
a partition between them. The partition is the proper 
ethmoid, the lamina perpendicularis of human anatomy ; the 
posterolateral parts of the ethmovomerine cartilages, on 
each side of the partition, occupy the situation of the pre- 
frontals, or lateral masses of the ethmmd of human anatomy. 
The ingrowths of the lateral walls, by which the nasal 



20 THE 1.NAT0UT OF TXBTEBBATED ANIUALS. 

mucouH menibraiie acquires a larger surface, are the Atr* 
binab. 

Riblike cartil^jnous rods appear in the first, Beoond, 
and, more or fewer, of the succeeding, Tiaceral arches in 
bub the lowest Veriebrata. The upper ends of the first and 
second of these become connected with the auditory capsule, 
which lies immediately aboTe them. 

The first Tiaceral arch bounds the cavity of the mouth 
behind, and marks the position of the 'mandible or lower jaw. 
The cartil^e which it contains is termed MeckeVg eartHage. 

The cartilaginonB rod contained in the second Tiaceral 

arch of each side is the rudiment of the kyoidean apparatns. 

Fig. 8. 




Fig. S.~1lDd«r-Tiew of the head of a Fowl at the Beventh day of in- 
cubation.— Ja, the cerebral bemispherea caueing the iaCegument to 
bulge; a, theeyea; g,the olfactory saca ; it, the fronto-naeal process; 
i, the maiillary proceu ; 1, 2, the first and second Tisceral andiea ; 
z, the temains ot the first visceral cleft. 

Like the preceding, it unites with its fellow in the ventral 
median line, where the so-called " body " of the hyoid arises. 
A ridge, continued forward from the first visoeral arch 
to the olfactory sac (Fig. 4, F ; Fig. 8, 1), bounds the mouth 
on each side, and is called the moieUlan/ proeeat. A carti- 
laginous ^lato-ptirygoU rod, dQTelo|)ed in this process. 



r 



THK FOBMS OF THE SKULL. 



becomes connected with Heckera cartilage behind, and with 
the prefronto! cartilage in front. 

The maxillary proceaa is, at firat, sepaxated by a notch 
correBponding with each naaal sac. from the boundary of 
the antero-median part of the mouth, which is formed by 
the free posterior edge of a fronio-nasal proataa (Fig. 4, F; 
Fig. 8, Ic). This sepuratea the naaal sacs, and contains the 
cartilaginous, ethmovomerine, anterior termination of the I 
skull. The notch ia eventually obliterated by the union of I 
the fronto-naaal and maxillary processes, externally ; but it J 
may remain open internally, and then giTes rise to thepo*- 1 
ierior 'nasal a^srtare, by which the nasal cavity ia placed in I 
i^ommunication with that of the mouth. I 

37iB General ModiJUations of the Vertebrnte Shali. — Tha 1 
lowest rertebrated animal, Amphioams, has no skull. In I 
a great many fiahea the development of the skull can-iea I 
it no farther than to a condition which ia eubstantially I 
similar to one of the embryonic st^^es now described ; that J 
is to say, there is a cartilaginous priTtiordial ci'amtivt, with J 
or without superficial grannlar ossifications, but devoid of ■ 
any proper cranial bones. The facial apparatus is either M 
incompletely developed, as in the Lamprey; or, the upper jaw I 
is represented, on each side, by a cartilage answering to the 1 
palato- pterygoid and part of Meckel's cartilage, while the a 
larger, distal portion of that cartilage becomes articulated 1 
with the rest, and forms the lower jaw. This condition is I 
iibservable in the Sharks and Rays. In other fishes, and 1 
in all the higher Vertebratu, the cartilaginous cranium and J 
facial arches may persiat to a greater or leas extent; but I 
bunes are added to them, which may be almost wholly tnem- j 
brane bones, aa in the Sturgeon; or may be the i-eault of i 
the ossification of the cartilaginous cranium itself, from | 
definite centres, as well as of the development of superim- J 
nosed membrane bones, I 

K|3%e Osseous Brain-case. — When the akull undergoes com- I 
^^Ke ossification, osseous matter is thrown down at not J 
^^■W. tiiAii tiiree points in the middle of its cartilaginoiUrJ 



th ^H 

ch ^^ 



22 THE ANATOMY OP TEETEBEATED ANIMALS. 

floor. The oaaific deposit, nearest the occipital foramen, 
becomes the biuti-occipital bone ; that which takea place in 
the fliwr of the pituitary fosaa becomes the baniiipheTund; 
that whicli appears ixx the reunited trabecolse, in front of the 
foBBa, gives rise to the preaphenoid. Again, in front of. and 
outside, the cranial cavity, the ethmoid may be represented 
by one or more distinct ossifications. 

An ossific centre may appear in the caitilage on each 
side of the occipital foramen, and give rise to the ex-occipital; 
and above it, to form the supra-occipital. The four occi- 
pital elements, uniting together more or lees closely, com- 
pose the QC&jntol eegment of the skidl. 

In front of the auditory capsulea and of the exit of the 
third division of the fifth nerve, a centre of ossification 
may appeaj- on each side and give rise to the aligphenoid; 
which, normally, becomes united below with the bafli- 
Bphenoid. 

In front of, or above, the exits of the optic nerves, the 
ortntoapKenoidal osaifications may appear and unite beloir 
with the presphenoid. 

In front of the occipital segment, the roof of the sknll a 
formed by membrane; and the bones which complete thetw 
segments of which the basisphenoid and presphenoid form 
the basal parts, are membrane bones, and are disposed in 
two pairs. The posterior are the parieials, the anterior the 
frrmlals; and the segments which they complete are re- 
spectively called jHineiai axiA. frontal. Thus the walls of the 
cranial cavity in the typical ossified skidl are divisible into 
three segments — I. Occipital, H. Parietal, III. Frontal— 
the parts of which are arranged with reference to one 
another, the aensory organs and the exits of the first, 
second, fifth, and tenth pairs of ci"anial nerves (i., ii., v., 
and X.), in the manner shown in the annexed diagram * : — 



• The naineg of Iho purely 


whlih a 


nailer type, m Babispbe- 


memhraiie booeB in this dinKiam 




are in large cnpitttla, sa P.\.Bl- 
ETAL ; while thou of Che bones 











THE TYPICAL BONY SKULL. 



23 






§• 



a. 

CO 



H 

O 

. § 

< . 6 

3" 



>«( 



Branchial apparatus. 



Hyoidean apparatus. 





I 



H 
Pi 



< 

a: 

9 

< 
en 



Em 



-ft 

I 

X 

S 

»J ^ 
< i=! 



25 
Oi 



Mandibular Suspensorium. 



o 

'A 
CO 



I 






o 

'A 
U 

i 

o 



Prefrontal. 






O 

03 



o 

a 

CO 

-< 
P3 

Ai 






i 



g 

•-3 

• 

Q 



D 

►-9 



}• 







1-3 












1 



24 



THE ANATOMY OF YERTEBBATED ANIMALS. 



The cartilaginous cases of the organs of hearing, or the 
periotic capsules, are, as has been said, incorporated with the 
skull between the ex-occipitals and the alisphenoids — or, in 
other words, between the occipital and the parietal segments 
of the skuU. Each of them may have three principal ossifi- 
cations of its own. The one in front is the pro-otic ; the one 
behind and below, the opisthotic; and the one which lies above, 
and externally, the epiotic. The last is in especial relation 
with the posterior vertical semicircular canal ; the first with 
the anterior vertical semicircular canal, between which, and 
the exit of the third division of the fifth nerve, it lies. These 
three ossifications may coalesce into one, as when they con- 
stitute the petrosal and mastoid parts of the temporal bone 
of human anatomy; or the epiotic, or the opisthotic, or 
both, may coalesce with the adjacent supra-occipital and 
ex-occipitals, leaving the pro-otic distinct. The pro-otic is, 
in fact, one of the most constant bones of the skull in the 
lower Vertehrata, though it is commonly mistaken, on the 
one hand for the alisphenoid, and on the other for the 
entire petro-mastoid. Sometimes a fourth, pterotic ossifi- 
cation, is added to the three already mentioned. It lies on 
the upper and outer part of the ear-capsule between the 
pro-otic and the epiotic (see the figure of the cartilaginous 
cranium of the Pike, infra). 



In some Vertebrata the base of the skull exhibits a long 
and distinct splint-like membrane bone* — the parasphenoidf 
which underlies it from the basi-occipital to the pre- 



* Bones may be formed in two 
ways. They may be preceded by 
cartilage, and the ossific deposit 
in the place of the future bone 
may at first be deposited in the 
matrix of that cartilage; or the 
ossific deposit may take place, 
from the first, in indifferent, or 
rudimentary connective, tissue. 
In this case the bone is not pre- 
figured by cartilage. In the skulls 
of Elasmobranch fishes, and in 
the sternum and epicoracoid of 



Lizards, the bony matter is simply 
ossified cartilage, or cartilage bone. 
The parietal or frontal bones, on 
the other hand, are always devoid 
of cartilaginous rudiments, or, in 
other words, are memhrane bones. 
In the higher Vertebrata the 
cartilage bones rarely, if ever, re- 
main as such; but the primitive 
ossified cartilage becomes, in great 
measure, absorbed and replaced 
by membrane bone, derived from 
the perichondrium. 



THE BONES OF THE FACE. 25 

sphenoidal region. In ordinary fishes and Amphibia, this 
bone appears to replace the basisphenoid and presphenoid 
fnnctionallj, while in the higher Vertehrata it becomes 
oonf oonded with the basisphenoid. The Vomer is a similar, 
splint-like, single or double, membrane bone, which, in like 
manner, underlies the ethmoid region of the skull. 

In addition to the bones already mentioned, a prefrontal 
bone may be developed in the prefrontal region of the nasal 
capsule, and bound the exit of the olfactory nerve externally. 
A poetfrontaZ bone may appear behind the orbit above the 
alisphenoid. Sometimes it seems to be a mere dismember- 
ment of that bone ; but, in most cases, the bone so named 
is a distinct membrane bone. 

Furthermore, on the outer and upper surface of the 

auditoiy capsule a membrane bone, the squamosal, is very 

commonly developed ; and another pair of splint-bones, the 

nasals, cover the upper part of the ethmovomerine cham- 

. bers, in which the olfactory organs are lodged. 

The Osseous Facial Apparatus. — The bones of the face, 
which constitute the inferior arches of the skull, appear 
within the various processes and visceral arches which 
have been enumerated. Thus, the prem/ixilke are two bones 
developed in the oral part of the naso-f rontal process, one 
on each side of the middle line, between the external nasal 
apertures, or anterior nares, and the anterior boundary of 
the mouth. 

Ossification occurs in the palato-pterygoid cartilage at 
two chief points, one in front and one behind. The ante- 
rior gives rise to the palatine bone, the posterior to the 
pterygoid. Outside these, several membrane bones may 
make their appearance in the same process. The chief of 
these is the maaiUa, which commonly unites, in front, with 
the premaxilla. Behind the maxilla there may be a 
second, the jugal; and occasionally behind this lies a 
third, the qaoArato-jugal. 

Between the maxilla, the prefrontal, and the premaxilla, 
another membrane bone, called lachrymal, from its ordinary 



26 THE AJtAIOMT OF TEBTESRATED AMIHAI.S. 

relation to the lachiymal (^anal. is verj generallj developed; H 
and one ur nune gapra-orbital and post-orhital oB^fioatioiu 
may he conaei-ted with the hony houndariea of the orbit. 

When these and the poatfrontal membrane bone are 
aimultjineonalj developed, they form two serioa of bonj 
Bpliata attached to the lateral wall of the skoll, 
above and one below the orbit, which converge to the lacb 
rymal. The upper aeries (iaehvymal, anpra- orbital, potf 
frontal, BquamoBol), terminatea poaterioily over the pn>^ 
mal end of the qiuidrati! bonf, or mandibular ?t^ensi?rtw)L 
The lower series (lachrymal, maxiUary, jugal, qnadraUK 
jugal) ends over the diatal end of that bone, with which 
quadrato-jugal ia connected. The two series are connected 
behind the orbit by the poat-orbital (when it exists), 
more commonly by the VLuion of the jngal with the poaib 
frontal and squiunoBai. The Ichthyosauria. Chelonia, Cro» 
dUia, and some Laeertilia, exhibit this double aeriea of bona 
most completely. 

Each naaal passage, at firat very short, passes betwea 
the premaiilla below, the ethmoid and vomer on the innK 
side, the prefrontal above and extemuUy. and the palatint 
behind, to open into the fore part of the mouth. A 
before the cleft between the outer posterior angle of 
naao-frontol process and the maiillary proceea is cIomA 
this passage cumimmieaces, laterally, with the 
and, posteriorly, with the cavity of the orbit. Whoi 
maxillary and the naao-frontal proceases unite, the 
external communication ceases; but theorbito-nasal 
or laehrymal canal., aa it ia called, in consequence ot 
function of conveying away the secretion of the lacl 
^and. may persist, and the lachrymal bone may be 
veloped in especial relation with it. 

In the higher Vertebratu, the nasal passages no long^ 
municate with the fore part of the cavity of the mouth; 
the maxillariea and palatines, regularly, and the pt«ry( 
bonea, occasionally, send proceases downwarda and in 
which meet in the middle line, and shut otf from the 



THE OSBBOU8 MANDIBLE. 27 

a canal which reoeires the nasal passages in front, while 
it opens, behind, into the pharynx, by what are now the 
posterior narti. 

Two ossificationa commonlj appear near the proximal end 
of Meckel's cartilage, and become bones moveable articulated 
together. The proximal of these is the qwtdrale bone found 
in most Tertebrates, the tnaUeus of mammals ; the distal is 
the 08 articttlare of the lower jaw in moat vertebrates, but 
Fig. 9. 




•c, N; Euatachim 



be, £«. 



does not seem to be represented in mammala. The re- 
mainder of Meckel's cartilage usually persists for a longer 
or shorter time, but does not osaify. It becomes surrounded 
by bone, ariaing from one or several centres in the adjacent 
membrane, andthe ramue ofthemandibh thus formed, articu- 
lates with the squamosal bone in mammal b, hut in other 
Yertebraia is immoveably united with the oe articidare, 
Eoice the complete ramus of the mandible articulates 



? TEBTBBRATED ANIMALS. 

directlj with the skull in mamniale, but onlj indirectlj, « 
through the uitemiediatioB of the quadrate, ixi other Veiit- 
iyrata. In birds and reptUee, the proiimal end of the 
qnadrate bone, articulatea directly Iwith a merely apparent 
exception in (^hidia), and independently of the hyoidea; 
apparatus, with the periotic capsule. In most, if not oi 
fiflheB, the connection of the mandihular arch with the aknll 
IB effected indirectly, by ita attachment to a single cartilage 
or bone, the hyomandihular, which represents the proximal 
end of the hyoideaji ai'ch (see Pig. 24). 

The Qsaificiktion of the hyoidean apparatus va 
raensely in detail, but usually gives rise to bony lateral 
urcbeB, and a median portion, hearing much the some rela- 
tion to them as the sternum has to the ribs. When the 
luterul arches are complete they are connected directly with 
the periotic capsule. 

The proidmal end of the hjoidean arch is often u 
more or less closely, with the outer extremity of the bone, 
o&lled coluimello, av/ri», or Hapea, the inner end of mhich, 
in the higher Vertehrata, is attached to the membrane of the 
fmmttra wait*. 

In ordinary fiahea, a fold of the integnment extendi 
bnckwardB from the second visceral arch over the par- 
Riatent branchial clefts; within this is developed a aeria 
of raytike membrane bones, termed opttrcuirtr and Irroii- 
eldonfegal, which become closely connected witb thehyoidean 
uruh. A uorreeponding process of the skin is developed in 
the Batriiuhiau Tadpole, and grows backwards over the 
br&nchin. Its posterioredge, at first free, eventually unites 
with the integnment of the body, behind the branchial clefts, 
the union being completed much earlier on the right aid^ 
than on the left, 

In most mammuls a similar fold of integument givM 
rise to the pinna, or external cur. 

The hrntuihial skiiliitun bears the same relation to tiu 
posterior visceral arehns that the hyoidean does to Uw- 
r.wcond, When fully ileviOojied. it exhibits ossified lateral 
urcliBB, connected by iumIIuu pioctis, and, frequently, j 



vided with radiating appendages whicli give support to the 
branchial mncons membrane. It is onlj found in those 
Yertebrata which breathe bj gilla — the classes Piice* and 




Fig. 10.— The akull of a Plaice (Plaltna vulgarU), viewed from above- 
liie dotted iine a, b, is tlie true morpboloKiul median line ; Or. Or, 
the paeiti<Hi of the tvo eyes in tbeir orblla ; Elk, etliinoid ; Prf, 
prefrontAl ; J^, left ftvnlal ; Fri, right frontal ; Pa, parietal ; 80, 
iapr«-occipitai ; ^- O, epiotie. 

Am^ibia. In the higher V^tebrata, the posterior of the two 
pairs of cwmna with which the hjoidean apparatus is geue- 
nlly providedi are the onljremaius of the branchial skeleton. 



30 THE ANATOMY OF YEBTEBBATED ANIMALS. 

The skull and face are usually symmetrical in reference 
to a median vertical plane. But, in some Cetacea, the bones 
about the region of the nose are unequally developed, 
and the skull becomes asymmetrical. In the Flatfishes 
[FleuronectidcB), the skull becomes so completely distorted 
that the two eyes lie on one side of the body, which is, in 
some cases, the left, and, in others, the right side. In 
certain of these fishes, the rest of the skull and facial bones, 
the spine, and even the limbs, partake in this asymmetry. 
The base of the skull and its occipital region are compara- 
tively little affected; but, in the interorbital region, the 
frontal bones and the subjacent cartilaginous, or mem- 
branous, side-walls of the cranium are thrown over tQ one 
side ; and, frequently, undergo a flexure, so that they become 
convex towards that side, and concave in the opposite di- 
rection. The prefrontal bone of the side from which the 
skull is twisted sends back a great process above the eye of 
that side, which unites with the frontal bone, and thus in- 
closes this eye in a complete bony orbit. It is along this 
fronto-prefrontal bridge that the dorsal fin-rays are con- 
tinued forwards, just as if this bridge represented the 
morphological middle of the skull. (Fig. 10.) 

The embryonic Plev/ronectidce have the eyes in their 
normal places, upon dpposite sides of the head ; and the 
cranial distortion commences only after the fish are hatched. 

The Appendicular Endoskeleton, — The limbs of all verte- 
brated animals make their appearance as buds on each side 
of the body. In all but fishes, these buds become divided 
by constrictions into three segments. Of these, the proximal 
is called hrachitmi in the fore-limbs, femv/r in the hind; 
the middle is antebrachivmi, or cms ; the distal is marms, or 
pes. Each of these divisions has its proper skeleton, com- 
posed of cartilage and bone. The proximal division, 
normally, contains only one bone, os hwmeri, or hwmeruay 
in the brachium — and osfemorisy or f&m/wr, in the thigh ; 
the middle, two bones, side by side, radius and ulna, or 
tihia and fibula; the distal, many bones, so disposed as to 
form not more than five longitudinal series, except in the 



M 1HE CA&PIie AMD THE fARSUS. 31 

Icklhyonaitria, where marginal bones are added, and some 
of the digits bifurcate. 

The ekeletaJ elements of the manua and pea are divi- 
sible into a proximal set. conatituting the carpus or iarnia : 
and a diatal set, the digits, of which there are normally five, 
articulated with the distal bones of the ca:rpue and tarauB. 
Each digit has a proximal ham-diyital (metaearpal, or meia- 
/iTMuObone, upon which follows a linear aeries at plialanges. 
It is convenient alwaya to count the digits in the same waj, 
tummeneing from the radial or tibial side. Thus, the thumb 
is the first digit uf the hand in man ; and the great toe the 
first digit of the foot. Adopting this sjetem, the digits 
may be represented by the numbers i, ii, iii, iv, v. 

There ia reason to believe that, when least modified, the 
cnrpuH and the tarans are composed of skeletal elements 
"hich are alike in number and in arrangement. One of 
tlieae, primitively sittuited in the centre of the carpus or 
btrsuH, ia termed the centrals ( on the distal side of this ai 
five carpalia, or twrM^lia, which articulate with the several 
luetacarpaJ or metataraal bones ; while, on its proximal ai 
are three bones — one radiah or tUnale, artioulating with the 
i-adiuB or tibia; onuulnaireorfilmlare, with the ulna or fibula; 
and one intetinedLum, situated between the foregoing. Car- 
pal and tarsal bones, or cartUages, thus diaposed are to be 
met with in some Amphibia oaA Chelonia(F\g. 11), but, com- 
monly, the typical arrangement is disturbed by the suppres- 
sion of some of these elements, or theb" coalescence with 
one another. Thus, in the carpus of man, the radiale. in- 
termedium, and ulnare are represented by the aeaphoides, 
lunare, and caneiforme reapectively. The piaiforme ia a 
aeaamoid bone developed in the tendon of the flexor carpi 
utitarie, which has nothing to do with the primitive carpus. 
The centrale is not represented in a distinct shape, having 
probably coalesced with one of the other elements of the ' 
i/aqius. The fourth and fifth carpalia have coalesced, and j 
h farm the single 'inciforme. In the tarsus of man the astra- 
~ a represents the coalesced tibiale and intermedium; the ' 
1, the fibulare. The liaiiiieitlare is the centrale. Like- \ 




THE AHATOMT OP TKETEBSATED ANIMALS. 




Fig. 11.— The riglit forefoot of the Cheluniui Clielgdra. iati the 

hi ntl- foot of the Amphibian Su/umasrfra.— Er. ulnft; It. mdiiu;"/. 

Gbulu; T. tibia. 
Proxima,! carps) bnnsB : r.railiste; i. intermedium ^ H.ulnaie; 

cenlnile is the middle unleltercd lione. 
Proumal tunBl boaea : (. iibiiile ; i. iatermeilium ; /. fHiulare ; e. 

tnilc; ], 2, 3, i, S, distal carpalia aad tanaUsi; i, u, in, i 

57(e Poeitioii of the I/imbe.^-ln their primitive poaitimit 
the limbs are straight, and are directed outwards, at ridd 
anglcB to the aiia of the body ; but, as developnient pro- 
eeeda, they become bent in such a, luaoner that, in the 
firet place, the middle diyision of each limb is flexed down- 
wards and towards the middle IJue, upon the proidmai diTi- 
aion ; wliite the distal diAdsion takes an opposite bendupMi 
the middle division. Thus the ventral aspects of the a 
braehiyiiit and erne come to look inwardly, and the dorsftl 
aapects outwardly; while the ventral aspects of the mt 
and pes look downwards, and their dorsal aspects look up- 
wards. "Wheji the poBition. of the limbs has been no furtier 



■ THE POSITION OF THS LIMBS. 

altered than this, the radiua in the antebrachium, and the 
tibia in the crua, are turned forwards, or towards the head ; 
thi! ulna and the fibida backwards, or towards the caudal e: 
tremity. On looking at these parts with respect to the axis 
of the limb itaelf , the radius and the tibia are pre-axidl, or 
in front of the axis ; while the ulna and £bula are poat- 
aadal, or behind it. The same axis traverses the centre of 
the middle digit, and there are therefore two pre-axial, or 
radial, or tibial digits; and two post-axial, or idnar, or 
fibular digits, in each limb. The most anterior of the 
digits (i) is coiled, poller, in the manua ; and hallvx, ii 
pes. The second digit (ii) ia the index ; the third (iii) the 
iiiedlTia ; the fourth (iv) the OMmdaria ; and the fifth (v) 
the minimit*. 

In miLDy Amphibia and BeptHia, the limbs of the adult do 
not greatly depart from this primitive position; but in 
birds and in mamntals. further changes occur. Thus, in 
all ordinary quadrupeds, the braohium is turned back- 
wards and the thigh forwards, so that both elbow and 
knee lie close to the sides o£ the body. At the same time, 
the forearm ia flexed upon the arm, and the leg upon the J 
thigh. In Wan a still greater change occurs. In the j 
natural erect posture, the axes of both arm and leg are 
parallel with that of the body, instead of being perpendi- 
cnlar to it. The proper ventral Burface of the brachimn 
looks forwards, and that of the thigh backwards, while the 
dorsal surface of thelatter looks forwards. The dorsal sur- 
face of the antebrachium looks outwards and backwards, 
thiit of the leg directly forwards. The dorsal surface of the ^ 
manuB ia estemal, that of the pes, superior. Thus, speafe- 
ing broadly, the back of the arm corresponds with the front I 
of the leg, and the outer aide of the leg with the inner side 
of the arm, in the erect position. 

In Bats, a line drawn from the acetabulum to the foot if 
also, in the natural position, nearly parallel with the long I 
uiia of the body. But, in attaining this position, the l 
IB bent at the knee and turned backwards ; the proper | 
il.ipi i v l surface of the thigh looking upwards and forwards^ 



34 THE AUATOMT or VEETEBR4TED ANIMAIH. 

while the correaponding surface of the leg looks backwafde 
and upwards, and the ungual phalanges are turned bact 
wards. 

The chief modifications of the mauus and pes arise 
fi-om the excesB, or defect, in the development of particular 
digits, and from the manner in which the digits are con- 
nected with one another, and with the carpus or tareuB. Li 
the leMhyosauria and Fleeiosawria, the Turtles, the Cetaeea 
and Sirenia, and, in a less degree, in the Seals, the digits an 
hound together and cased in a common sheath of integn- 
ment, so as to form paddhx, in which the several digits have 
little or no motion on one another. 

The fourth digit of the manus in the Fterosawria, and 
the four ulnar digits in the Bats, are vastlj elongated, ta 
support the web which enables these animals to Qj. In 
existing birds the two ulnar, or post-axial, digits are abort«d, 
the metacarpals of the second and third aa'e ankylosed to- 
gether, and the digits themselves are inclosed in a common 
integumentary sheath; the third invariably, and the sefMnd 
usually, ia devoid of a claw. The metacarpal of the pollei 
is ankylosed with the others, but the rest of that digit is 
free, and frequently provided with a claw. 

Among terrestrial mammals, the moat striking changes of 
the manuB and pee arise from the gradual reduction in the 
number of the perfect digits from the normal number of five 
to four (Sus), three [Bhinoceros), two (most Riiminantia), or 
one (Equidm). 

Tlie Pectoral md Pelvic Arekeg.—'The proximal skdetal 
elements of each pair of limbs (fcwmeri or femttra) arc 
supported by a primitively cartilaginous, peciora?, or pebrie 
girdle, which lies external to the costal elements of iSiA 
vertebral skeleton. This girdle may consist of a simpte 
cartilaginous arc (as in the Sharks and Bays), or it maj bfl 
complicated by aubdivisions and additions. 

The pectoral arch may bo connected with the aVuU, or 
with the vertebral column, by mnseles, ligaments, or dermal 
ossifications, though, primitively, it is perfectly free from 



THE PECT0K4L ARCH. 

and independent of, both ; bat it ia never united with the 
Tertebne by the intermediation of ribe. At first, it consisto^ 
of one continaouH cartilage, on each aide of the body, dia- 
tinguiahable only into regions and proccBsea. and affording 
an articu]a,r anrface to the bonea, or cartilageSj of the limb. 
Bat OBsification usually Beta np in the cartilage, in such a 
way, as to give rise to a dorsal bone, called the scapula, orj 

aboulderblade, which meets, in the articular, 

cavity for the hnmeruB, with a ventral oasification, termed 

the eoraeuid. 
By differences in the mode of ossification of the varior 

parts, and by other changea, that region of the primitiveW 




Pig. 2 b de-v ew of the pcD n a cb and b e i 
{lyuata lubcrca aCa) — ^ Ka.p a supra Boapn! 

tod g f: enoidnJ ca ilj Si tcmum x xiph 9 enii 
TneAuBcepu it p p ecora o d puct mesocoracDid cr 
Qoid, eJ^ohiMole, i.ci, interclavlole. 

I caxiilaginouB pectoral arch, which lies above the g 

carit^i may be altimately divided into a scajmlaajid atuprd-J 

I xapulai while that which hes on the ventral side may pre-^ 

: pot only a coraeoid, but a, preeoraeoid and an i 

eoraeoid^ 

t majjotitiy of the Veriebrata above fiBlie«, tJ 



0¥ VE£TBBBATED ANIMALS. 

coracoids are large, and articulate with the antero- external 
margins of the piiinitiveSy cartilaginous demum, or breast- 
bone. But, in most mammals, tliey do not reach the eter- 
num. and, bepoming anijioaed -with the scapula, thej 
appear, in adult life, aa mere proeeBsee of that hone. 

Numerous Vertehi-ates possess a clavieuio,, or oollar-bone, 
which is connected with the pre-asial margin of the scapula 
and coracoid, but takes no paii in the formation of the 




glenoid cavity, and ia usually, if not always, a membrane 
bone. In many Vertehrala, the toner ends of the claviclea 
are connected with, and supported by, a median membrane 
bone which is closely connected with the ventral face rf 
the sternum. This is the intgrclavicula, frequently called 
epiatemum. 



THE PELVIC ABCH. 

The pelvic, tike the pectorul, arch ut first cuneists of »M 
simple continuouB cai'tilage on each aide, which, in Verts' J 
brala higher than fishes, ia divided by the acelabulm. 
articular cavity for the reception of the bead of the fetnui 
into a dorsal and a ventral moiety. 

Three sepamte oHsificatiunH usually take place i 
cartilage — one in the dorsal, and two in the ventral, moiot^jfl 
Hunce, the pelvic arch eventually consiata of a dorsal powi 
tion. called the ilium, and of two ventral elements, thepid 
anteriorly, and the iBchiv/m posteriorly. All these genera 
enter into the composition of the acetabulum. 

The ilium corrosponde with the acapnia. In the bighai 
Vertebrata the ont«r surface of the latter hone becomi 
Fig. U. 




Fie. 1 



dirided by a ridge into two fossie. The ridge, called the 
ipine of the aeapv-la, frequently ends in a prominent procasa . i 
temied the ocromion, and with this, in Mammalia, the clw 
nole artJonlatea. In like manner, the outer surface of t; 
ilium becomes divided by a ridge which grows out into a 
^rreat crest in Man and other Mammalia, and gives attach^ 
m«nt to niuacles and ligaments. 
The ■«^ ph i" iT ' corresponds very nearly with the c 



in the pedtoiiil arch; the puhis with the pvecorucoid, and 
more or leea of the epiooracoid. 

The pelvis poBseeaes no osaeoua element correBponduag 
with tbo claricle, bat a etrong ligament, the so-called Pim- 
parfs ligament, stretches from the ilium to the pubis in 
many Vei-tebrata, and takes its place. (Fig. 14, Pp.) 

On the other hand, the iimfeupinl bouea of certain mam- 
mals, which are oBsifications of the tendons of the eEternal 
oblique muBcleH, seam to be imrepresented in the pec- 
toral arch ; while thei'e appears to be nothing cleai-ly eorre- 
spoudiug with a sternum in the pelric arch, though lis 
precloacal cartilage, or oeside, of Lizards has much the same 
relation to the iachia as the sternum has to tho coracoids. 

Very generally, though not nniversally, the ilia are cloaelr 
ai'ticulated with the modified ribs of the sacrum. The pubet 
aud ischia of opposite sides nBaally meet in a median 
ventral symphyats ; but in all birda, exoept the Ostrich, this 
union does not take place. 

Tlie Limbs of FishBe. — The limbs of Fishes have an endo- 
akeleton which only imperfectly corresponds with that of 
the higher Vertebrates. For while homologues of the car- 
tilaginous, and even of the bony, conatituenta of the pec- 
toral and pelvic aixihes of the latter are traceable in Fishea, 
the cartilaginous, or ossified, baaal and radial supports ot 
the fins themselves cannot be identified, unless in the moat 
general way, with the limb-bones, or cailalages, of the other 
Vertebrata. 

In its least modified form, as in Lepido»iiren, the endo- 
skeleton of the fish's fin is a simple cartilaginous rod, 
divided into many joints \ and articulated, by its proximal 
end, with the pectoral ai'cb. The SlasmobranckH posaesa 
three basal cartilages which articulate with the pectoral 
arch, and are called, respectively, from before backward! 
— propterygial, meaopterygial, and inetapterygiul baaa^. 
With theae are articulated linear series of radial cartilage^ 
upon which osseous, or homy, dermal fin-rays are super- 
imjoaed. (Fig. 15.) 



THK LIMBS OF FISHES. dS 

Among tbe Ganoid fishes, the fins of Polypterua are, f im- 
dameutallj, like those of the EUismobranchii ; but the pro- 
pterygial, mesopterygial, and metapterjgial basalia, are 
more or less ossified, and are succeeded by a series of elon- 
gated Todialvi, which are also, for the most part, OBsifled. 
JBeyond these follow some small additional radialia, which 



Fig. 15, 




remain cartilaginone, and are embraced by the bases of the 
fin-rays. In the other Ganoids the propterygial basale dis- 
appears, and some of the radialia, pushing themselves be- 
tween the mesopterygial and raetapterygi^ basalia, articu- 
late directly with the pectoral arch. The mesopterygial 



40 THE ANATOMY OF YEBTBBBATED ANIMALS. 

basale is embraced by, and becomes more or less incorpo- 
rated with, the large anterior fin-ray. 

From these Ganoids the passage is easy to the Teleostei, 
in which, also, the mesopterygial basale always becomes 
fused with the anterior fin-ray, whence the latter seems to 
articulate directly with the shoulder-girdle. Four bones, of 
very similar general form, usually articulate with the pec- 
toral arch, beneath and behind the mesopterygial basale 
and its fin-ray. At their distal ends small cartilaginous 
nodules may lie, and these are embraced by the fin-rays. 
Of these four bones, or partially ossified cartilages, the lower- 
most and hindermost answers to the metapterygial basale 
of the Shai'k; the others seem to be radialia. (See the 
figure of the Pike's pectoral fin, infra,) 

The ventral fins have basal and radial cartilages and fin- 
rays, more or less resembling those of the fore limbs. 

In most Ganoids and Teleosteans the pectoral and pelvic 
arches are, in part, or completely, ossified ; the former fre- 
quently presenting distinct scapular and coracoid bones. 
To these, in aU Ganoids and Teleosteans, membrane bones, 
representing a clavicle, with sv^a-clavicular and post-clavi- 
cular ossifications, are added. 

In aU Elasmobranchs and Ganoids, and in a large pro- 
portion of the Teleosteans, the pelvic fins are situated far 
back on the underside of the body, and are said to be 
" ventral " in position ; but, in other Teleosteans, the ventral 
fins may move forward, so as to be placed immediately 
behind, or even in front of, the pectoral fins. In the former 
case they are said to be " thoracic," in the latter " jugular." 

The Vertebrate Exosheleton, — ^The Exosheleton never attains, 
in vertebrated animals, the functional importance which it 
so frequently possesses among the Iwoertehrata, and it varies 
very greatly in the degree of its development. 

The integument consists of two layers — a superficial, non- 
vascular substance, the epidermisy composed of cells, which 
are constantly growing and multiplying in the deeper, 
and being thrown off in the superficial, layers ; and a deep 
vascular tissue, the dermis, composed of more or less 



r 



THE EXOSEELETOH. 41 

Jompletely-formed conneetive tiasue. An eioskeleton may 
l)e developed ty the bardemng of either the epidermis, or 
.he dermis. 

Tlie epidenjMi? exoekelelon, reaulta from the conveTBion into 
lornj matter of the Buperficial cells of the epidermis. The 
lovuj plates thae formed are moulded upon, and follow the 
ionfigumtion of, arete, or proceBsea, of the dennia. When the 
atter are overlapping folds, the homj epidermic ittveatment 
s called ft scale, JijMnma. When the dermic process is papilli • 
orm, and sunk in apit of the dermis, the conioal cap of modi- 
ied epidermis which coats it, is either a hair or a/eaifter. To 
>ecome a hair, the horny cone simply elongates by coutinuaJ 
tddition of new oella to its base ; but, in a feather, the horny 
■one, which also elongates by addition to its base, splits up, 
Eor a greater or less distance iJong the middle line of its 
ander-surface, and then spreads out into a flat vane, sub- 
divided into barbt, barbulet, &c,, by a further pi-oceas of 
splitting of the primary homy cone. 

The epidermis remaina soft and delicate in Fishes and 

A^n^hibia. In Reptilia it sometimes takes the form of 

plates, which attain a great siae in many Chehmia; aome- 

timee, that of overlapping scales, as in Ophidia and many 

JjoeertUia ; but, sometimes, it remains soft, aa in some C/te- 

lonia and is the ChaniffilconB. Epidermic plates in the form 

■ if naiU appear upon the terminal phalangea of the limbs. 

All AveK posaeaa featbera. In addition, the beak ia partly 

[* completely enaheatbcd in bom, aa in aomc Meptilia. 

ified epidermic tubercles, or piatea, are developed on 

LtaiBi and toea, the terminal phalanges of which (and 

mes those of the wing) have nails. Beside these, 

e birds posseaa spurs, which are enaheathed in born, on 

■.legs or winga, 

1 Jfommulia the homy esoakeleton may t4ike all the 

i8 already mentioned, except that of feathers. In aome 

B almost absent, being reduced to a few haira, 

lent only in the ftetul atate. The Pangolin {Sfanie), ( 

t other hand, is almost completely covered with scales, 

■Artnadillos with plates, and most terrestiial mammals J 



42 



TKK ANATOMY OF VEETBBBATED ANIMiLS. 



with a, thick coat of hair. The greater part of the mass of 
the homB of Oxen, Sheep, and Antelopes, is due to th 
dermic eheath which covera the bouj core. Where ti* 
bomy epidermis becomes vei^ thick, aa in the hoof of tlu 
Horse, and in the horn of the Bhinooeros, numerous long j 
papillfe of the dermis extend into it. These papilte, ho** 
ever, are comparable to the ridges of the bed of the BaH, f 
not to the papilla; of the hairs. 

Fig. 16. 




Fig. 16.— A, ouiline oF a Pilte (Esox), tn show the fiiiB : P. pccMrtlj 
J', vonlrnii A, anal; C, caudal; D, dorsal, Bns. Oyi., operculoa: 
/'.0/',,preoperouluin ; Jr.,braQehioBtegalrayB.— B,BCalosol'llied<B 
mal excwkeletan of Ihe sune fish. 



The dermal exosieleion arises from the haidening of 
dermis; in the majority of cases by the deposit of b(n6> 
eai-th, in more or less complet-ely-fovmed connective 
though the resulting hard lissuebaabynomeane alwajBtlu 
atructure of bone. It may happen that cartilage is T 
veloped in tie dermis; and, either in its primary state, 
ossified, gives rise to axoskeletal parts. 

No dermal eioskeleton (except that of the fin-rays) {( 
found in the lowest tishes, Amphioxvs and the Martipo- 
braachii. In most Tehostei the integument is raised up 
into overlapping folds; and, in these, calcification 



THE EXOSKELETON. 43 

place in laminse, of which the oldest is the most superficial, 
and lies immediately beneath the epidermis. As a general 
rule, the calcified tissue of the " scale " thus formed, does 
not possess the structure of true bone in the Teleostei, But 
in other fishes, the dermal calcification may consist of true 
bone (as in the Sturgeon) ; or, as in the Sharks and Rays, 
may take on the structure of teeth, and consist mainly of a 
tissue exactly comparable to dentine, capped with enamel» 
and continuous by its base with a mass of true bone, which 
takes the place of the crusta petrosay or cement of the teeth. 

A form of dermal exoskeleton, which is peculiar to and 
bighly characteristic of fishes, is found in thefrnrrays. These 
are developed in the integument either of the median line of 
the body, or in that of the limbs. In the former case, they 
usually enter into, or support, folds of the integument which 
are termed dorsal, caudal, or anal fins — according as they 
lie in the dorsal region, or at the extremity of the body, or 
on the ventral aspect, behind the anus. Ordinary fin-rays 
are composed of a hornlike, or more or less calcified, sub- 
stance, and are simple at the base, but become jointed trans- 
versely, and split up longitudinally, towards their extremities 
(Fig. 6). Each fin-ray consists of two nearly equal and simi- 
lar parts, which cohere by their applied faces for the greater 
part of their extent ; but, at the base of the ray, the halves 
commonly diverge, to embrace, or more or less completely 
coalesce with, cartilaginous or osseous elements of the exo- 
skeleton. In the median fins, these are the interspinous 
cartilages, or bones, which lie between the fin-rays and the 
superior or inferior spines of the vertebrae. In the paired 
fins, they are radial or basal, cartilaginous or osseous, 
elements of the endoskeleton. 

The Amphibia in general are devoid of dermal exoskeleton, 
but the CcBcilice have scales like those of fishes. Ceratophrys 
has plates of bone developed in the dorsal integument, 
which seem to foreshadow the plates of the carapace of 
the Chehnia ; and the extinct Labyrinthodonts possessed a 
very remarkable ventral exoskeleton. 

The Cfphtdia have no dermal exoskeleton. "M.airj lAiSbC^^ 



ii THE ANATOMY OP VEKTEBKATED 

have bony dermal plates correaponding in form and aiie 
with the epidermal scales. All Croeodtlia have such bonj 
plates in the dorsal region of the bodj and tail ; and in some, 
such aa the Jacares and Caimans, and the extinct TeUo- 
gfljiria, thej are also developed in the ventral region, hi 
these animalB there is a certain correspondence between the 
segments of the exosteleton and those of the endoakeletoii 
Bnt the dermal eioakeleton attains its greatest development 
in the Chelcmia, and will be partiuularlj described nnder tilt || 
head of that order. 

In the Mammalia the development of a deiinal exoalcdfr 
ton is exceptional, and occurs only in the loricated Edejitabi M 
in which the dorsal region of the head and body, and tilt V 
whole of the taQ, may be covered with shields of dermd '^ 

In connection with the dermis and epidermis, the glail- *i 
dular and pigmentary organs of the integument may bl M 
mentioned. Integumentary glands do not appear to ejdit Ij 
in Fishes, hut they attain an immense development in boM 4 
of the Jnip/iibta, aathe Frog. Among Beptifia, Lizards bV ■ 
qnently present such glands in the femoi'al and cloanl U 
regions; and, in Crocodiles, integumentary glands, which | 
secrete a musky substance, lie beneath the jaw. In Birdt 
they attain a considerable size in the uropygial gland ; Mi" 
in Maimmalia, acquire a large development in connection wil 
the saCB of the hairs, or as independent organs, in the fon 
of sweat-glands, musk-glands, or mammary glands. - 

The colom" of the integument may arise from pigr 
granules, deposited either in the epidermis or in ti< 
dermis j and in the latter case, it is sometimes contained ii 
distinct chromatophoree, as in the Chamteleon. 




CHAPTER U. 



i TERTEBBATA. 

'he muscular ajstem of the Verlebrata conaiatB of muscles 
ela,t«d partly to the exoskeleton, partly to the endoskeleton. 
nd partly to the viscera, and formed both of Btnat«d and 
nstriated muBColar fibre. The latter ia confined to the 
eesele, the viscera, and the iDtegument ; the paita of the 
ndoskeletoD being moved upon one another eiclusively by 
triated muscular fibre. The musclee of the endoekeleton. 
oay be divided, like the endoskeleton itself, into one eyatem 
Lppertaining to the truak and head, and another belonging 
x> the limbs. 

The Muscaiar Syglem of the Trmk and Head.— This eon- 
lists of two portions, which differ fundamentally in their 
origin, and in their relations to the endoskeleton. The one 
9 its origin in the protovertebrse ; each protovertebra 
ing differentiiited, as we have seen, into three parts ; 
1 ganglion and a segment of the vertebral endo- 
B plane, and a more superficial sheet 
innscular fibres. These musculai' fibres are consequently 
situated above the endoskeleton, or are epinkelelal. Other 
mufiCular fibres are developed below the endoskeleton, and 
miy be termed hyposkdetal mnsclee. The hyposkeletal 
nneclee are separated from the episkeletal. not only by the 
endoskeleton of the trunk (or the vertebrfe and their pro- 
loDgatious, the ribs), but by the ventral branches of the 
' mi nerves. 
■ the episkeletal muscles are developed out of the proto- 
I, they necessarily, at first, present as many seg- 



! 

I 




46 THE ANATOMY OF VERTEBBATED 

mente as tbere are vertebra, tbe mterapacea between tbera 
appearing as ialeriiiiiscular sepia. The development of the 
hjpoakeletal inusclca has not been worked ont, bnt it appean 
to take place much Inter than that of the episkeletal set. 

In the lowest Verfebrutct — as, for example, in ordinaij 
fishes — the chief mnscolar ayatem of the trtmk conaistB ^ 
the episkdetal muscles, which form thick lateral 
longitudinal fibrea. divided by ti-anaverse intermuacnlB 
aepta into segments (or Myotomen) correaponding with Ui« 
vert«br£e. The lateral musclea meet in the middle line 
below, and divide, in front, into a dorso-lateral mass CO* 
nected with the skull, and a ventro-lateral attached, in pui 
to the pectoral arch, and, in part, continued forwards to tie ^ 
akull, to the hjoidenn apparatus, and to the mandible. Pw ** 
teriorly, the lateral miiBcles are continued to the extrtotuQ 
of the tail. The hypoakeletal miiseular ayatem appean to '^ 
be undeveloped. ^ 

In the higher Vertebrata. both the epiakeletal and hypo- *J 
skeletal mnacular systems are represented by consideralli* ^ 
numbers of more or less distinct muscles. Tlie dono- 
lateral division of the lateral muscle of the fish is r^TO- 
sented by the anperior caudal muacles, and bj the 
epiiiiie i which, as it splits up, anteriorly, and beoomal ^ 
attached to the vertebrte, and to the ribs, and to the skolK ' 
acqniree the names of spinalis, nemiepiiudis. longissimlH 
dorei, saerolvmbalia, inteT'trcmfveraaUa, leuatores 
OMtipleieits, ^leniaa, recti poitid, and recti laterales. 

The ventro-lateral division of the fish'a lateral muscle 
represented, in the middle line of the trunk and head, byi 
series of longitudinal muacles; and. at the sides, by obliqi 
directed muscles. The former are the recti ahdoininu, 
tending from the pelvis to the sternum— the aterna- 
between the stemum and the hyoidean apparatt 
i/enio-hyoidei. which pass from the hyoid to the 
of the mandible. The latter are the obliqui taiemi of 
abdomen — the eitemal intercoslalen of the thorax — the 
olatnua stretching from the first rib to the clavicle; 
geolent from, the anterior dorsal ribs to the cerviutd ribe 



AND HYPOSKELETAI, MUSCLES. 



47 



transreree processes, and the stemo- ujid ehido-ineMtoidei 1 

. from the atemum and clavicle to the skull, 1 

The fibres of all these oblique mnaclea take a direction, 1 

from parts which are dorsal and anterior, to others which I 

are ventral and posterior. 

The trunk muscles of the lower Amphibia exhibit ar- 
rangements which are transitional between those obsei-ved 
in Fishes and that which has been described in Man, and ] 
K'bich Bubstantiallj obtains in all abranchiate Vertebrata. 

The muscles of the jaws and of the hyoidean apparatus 
appear to be, in part, epiakeletal, and, in part, hjposkeletal. 
The mandible is depressed by a muscle, the diguairu:, arising i 
from the sknll, and supphed by a branch of the seventh . 
nerve : it is raised by a muscular mass, which is separable 
into iiWMseier, temporal, and pterygoid muscles, according to 
its connection with the maiillo-jugal hones, the sides of the 
akull, or the palato-pterygoid bones, and is supplied by the 
fifth nerve. 

The proper facial muscles belong to the system of cuta- 
neous muscles, and receive branches from the seventh nerve. 
Tlie hypoakeletal system is formed, pu.rtly, of longi- 
tudinal muscles which underlie the vertebra! column ; and 
puttly, of more or less oblique, or even transverse fibres, 
which form the innermost muscular walls of the thorax and I 
i>f the abdomen. 

The former ai'e the subcaudal intrinsic flexors of the tail ; 

the pyr^oratit.paoas, and other muscles proceeding from the 

Uiferiov faeea of the vertebrfe to the hind limb ; the longua ' 

-■uUi, or intrinsic flexor of the anterior part of the vertebral I 

iijiimn; andtherscti capitU antlci, or flexors of the head ] 

i|iiin the vertebral column. The latter are the obUqwis 1 

iie-mUB of the abdomen, the fibres of which take a direction 

I'lHsing tliat of the external oblique muscle; and the tram- 

' ■ i-.-^tiivi, which lies innermost of the abdominal^piuscles, and 1 

lULs its fibres transverse. In the thorax, the inlereostalea 

^K^ni continue the direction of the internal oblique, and ' 

^^MnoTljmlam eterni that of the trmtsversaUe. The dui- 

^^B^_and the levator ani must also be enumerated among J 



48 THE ANATOMY OF YEBTEBBATED ANIMALS. 

the liyposkeletal muscles. The hyposkeletal muscles of the 
posterior moiety of the body attain a great development in 
those Vertehrata which have no hind limbs, such as Ophidia 
and Cetacea. 

The Muscular System of the Limbs. — The muscles of the 
limbs of Fishes are very simple, consisting, on each face of 
the limb, of bundles of fibres, which proceed (usually in two 
layers) obliquely, from the clavicle and supraclavicle to the 
fin-rays. The pectoral and pelvic arches themselves are 
imbedded in the lateral muscles. 

In the Amphibia and all the higher Vertebrata, the muscles 
of the limbs are divisible into — intrinsic,oT those which take 
their origin within the anatomical limits of the limb (in- 
cluding the pectoral or pelvic arch) ; and extrinsic, or those 
which arise outside the limb. 

Supposing the limb to be extended at right angles to the 
spine (its primitive position), it will present a dorsal a^spect 
and a ventral a^spect, with an anterior, or pre-asdal, and a 
posterior, or post-aadal, side. 

In the Vertebrata above fishes, the following muscles, which 
occur in Man, are very generally represented : 

Exi/riTisic muscles attached to the pectoral and pelvic arches, 
on the dorsal aspec . — ^In the fore limb, the cleidomastoideus, 
from the posterolateral region of the skull to the clavicle ; 
the trapeziums, from the skull and spines of many of the ver- 
tebrae to the scapula and clavicle ; the rhomboidei, from the 
spines of vertebrae to the vertebral edge of the scapula, 
beneath the foregoing. Sometimes there is a tracheh- 
acromialis, from the transverse processes of the cervical 
vertebrae to the scapula. 

On the ventral aspect, the svhclavius, which passes from the 
anterior rib to the clavicle, may be regarded as, in part, a 
muscle of the limb ; the pectoralis minor, from the ribs to 
the coracoid. 

Between the dorsal and the ventral aspects muscular fibres 

arise from the cervical and dorsal ribs, and pass to the inner 

aspect of the vertebral end of the scapula : anteriorly, these 

are called levator angrdiscapulAB ; poBteriorly , ierratv^ m>agnus. 



B THE MCSCLBS OF THE LIMBS. 49 

An omo/tTfOMi muscle frequently connects tlie acapnia _with 
the hjoideau iirch. 

The poet«rior limb doea not seuiu to offer anj muaclea i 
eiacUj homologous with the foregomg/ So fur, however, 

is the recti abdominis, the obliqwua exiernvs, and the fibres I 

of the erector spinte, are attached to the pelvic girdle, they ] 

con'espond in a. general way with the pi-e-asial, or protractor, ] 

Diuscles of the pectoral arch; and the iachio-coccygeal ] 

muscles, when they are developed, are, in relation to the 1 

^^Tic arch, reti-actora, though, owing to the relative fijaty 1 

Hteie pelvis, they act in. protracting, or flexing, the caudal 1 

^Htbe jMocu minor, proceeding from the under-eiirfaceB of I 
^Batcrior doi-sal (or lumbar) vertebra; to the ilium, or pubis, 1 
IB a protractor of the pelvis, hut, as a hyposkeletal muscle, 
has no homologue in the fore limb. 

EetHaidc miiscles aUached to the hanienia or femur, on thti 
doreal aspect, — ^In the fore limb there is the post-axial latissi- 
Tiiiua dorsi passing from spinee of dorsal vertebne to the 
humerus. On the ventrrU aepect, thepectoralis major extends 
£rom the sternum and ribs to the humerus. 

In the hind limb, the ghiiixnis ■mcaAm.'Os, so far as it arises | 
from the sacral and coccygeal vertebne, and is inserted into I 
the femur, repeats the relations of the laiiesimiue dorsi. In 
the absence of anything corresponding with the sternum, or 
the ribs, no exact homologne of the pectorulig major caii be . 
^:ai to exist, though the pectinevs comes near it. The psoon , 
I (Hij'or, passing from posterior dorsalor lumbar vertebi-ai— the i 
liiiriformis tioia sacral vertebras — the /emDro-eoecj/jeti* (when ! 
it exists) from caudal vertebne — to the femur, are all hypo- 1 
fkc'letal muscles, without homologues in the anterior ei- i 
iiviuity. ' 

All the othfr muscles of the limbs are intrinsic, taking 
nir origins from the pectoral or pelvic arches, or from 
'liiiie of the more prosimal segments of the limb- skeleton, 
and having theii" insertion in the more distal segments. 
They are thus arranged in Man and the higher Mammaliii. : 
Ittiriiusic jintscka, proceeding from the pectoral or pelvia I 



50 THE ANA-TOMT OP VBRTEBKATED 



arches to the hutnervs or femur, on the dorsal aspect, — In the 
fore limb, t!ie deltoides proceeds from the clayicle and scti- 
pulato the hunierua. This superficial shoulder-iuuscle cod^ 
tiniiea tlie du'SSt^Ikof the fibres of the trojpeUits ; and, vr 
the clavicle i&ju^neiitaij, the adjacent portion a of the 
nmaeleB co^leaSe mto a, eephdlo-kwrntralU muscle, 
the deltoi^ the Biawo-BpimaiiM, on the pre-axial side of tl* 
Bpine of the acapnia ; the infra-^inatus, and the tereg mt)g9t 
and miiior^io^m post-asial side, run from the dorsal asped 
of the sifewAi to that of the head of the humerus. 

In the i)iWm Hmh, the tensor vagituE femarig, whicli ptiiinn 
from thatViart of the ilium which corresponds -wiai tb^ 
spine and aci'omion of the scapula, to the femur, appeun tt 
onawer better to the deltoid than does the glulxevs maaAum 
which, at first sight, would seem to be the homologne rf 
that 

The ilMfous, proceeding from the inner surface of the 

Q to the smoiler trochanter, answers to the 

N the gtvicBos vtediiis and invaimtis, which arise fan 

\- sui-face of the ilium, to the infra-itpiiiaUis and 

a foro limb, a muscle, the eabeeapjili 

to theminer face of the scapula, and is inserted into the 

fclmm^ruB. No muscle esactly corresponding with tikii 

W>peara to exist in the hind limb. 

\pa t)ie veiiiral a^ect in the fore Hmh. the coracdbrackudit 

paslCs from the ooracoid to the humerus. In the hind limK 

^ a numbi-r of muscles proceed from the corresponding (iachio^ 

Aubic) part of the pelvic arch to the femur. These SI*. 

Jci'Om the outer surface of the pubis, the pectineas, and 

treat oddwttors of the femur ; with the dbturator ea ' 

^S sworn the outer side of the ischiopubio fontanelle, 

V ^vQttirator membrane. The gemelli and the yaadraftw/BWiorfl 

' ^^ y take their origin from the ischium. 

No muscle is attached to the proper inner surface of ti 
ilinm. so that there is no homologne of the s^AscapnUxrit : 
the hind limh. On the other bund, a muscle, the oftfuroter 
iiiiermis. attached to the inner surface of the ischiopnbis 
fontanelle, and winding round to the femur, has no honKK 



THE MUSCLES OP THE LIMBS. 51 

logae in the upper extremity of the higher Vertehrata, tmless 
it be the so-called corcLcobrachialis, which arises from the 
inner surface of the coracoid in many Sav/ropMa, 

Muscles of the Antebrachitmi and Cms. — On the dorsal aspect 
of the fore limb, as of the hind limb, certain muscles arise 
in part from the arch, and, in part, from the bone of the 
proxiinal segment of the limb, and go to be inserted into 
the two bones of the second segment. These are, in the 
fore limb, the triceps extensor and the supinator hrevis ; in 
the hind limb, the quadriceps extensor. 

There is this difference between these two homologous 
groups of muscles — that in the fore limb, the principal 
mass of the muscular fibres goes, as the triceps, to be 
inserted into the post-axial bone (ulna), and the less por- 
tion, as supinator hrevis, into the pre-axial bone (radius) ; 
whereas, in the hind limb, it is the other way, almost the 
whole of the muscular fibres passing, as the quadriceps, to 
the pre-axial bone (tibia), the tendon commonly developing 
a sesamoid patella ; while only a few fibres of that division 
of the quadriceps which is called the " vastus extemus " pass 
to the post-axial bone (fibula). 

On the ventral a^ect, the fore limb presents three muscles, 
arising either from the pectoral arch, or from the humerus, 
and inserted into the two bones of the forearm. On the 
pre-axial side are two muscles ; one double-headed, the biceps, 
arising from the scapula and the coracoid, and inserted into 
the radius. A second, the supinator longus, passes from the 
humerus to the radius. On the post-axial side, the hra- 
ehialis anticus arises from the humerus, and is inserted into 
the ulna. The hind limb has two muscles, the sartorius, 
arising from the ilium, and the gramlis, from the pubis, 
in place of the biceps hrachii, and inserted into the pre-axial 
bone, the tibia, which corresponds with the radius. Two 
other muscles, the semi-membranosus and semi-tendinosus, 
pass from the ischium to the tibia, and replace, without 
exactly representing, the supinator longus. Corresponding 
with the hra^ihialis anticus is the short liead oi V\ife^^^e?^% 
femoris, arising from the femur, and inserted mto ^i^i.e ^o^V 



52 THE ANATOMY { 

axial bone of the leg, the fibula. The long head of the 
ftjceps/emons, which pioceecls from the ischiani, appears lo 
have no representative m the foi-e limb. 

In the fore limb, a muscle, the pronator teres, j 
obliquely from the post-anal condyle of the LumernB to 
the radius In thp hind limb, a corresponding mascle, the 
poplUaua, proceeds from the poat-aiial condyle of the 
femur to the tibia. The pronator qwadrahis, which pasaei 
from the xdntt to the radius, has its analogue, 
Marsapialia and B^tilia, in muscles which extend fron 
the fibula to the tibia. 

The Musclea of the Digits. — The remaining muscleB cf 
the two limbs are, primarily, muscles of the digits, and or 
attached eithei- tothebaBi.digital(inetuc3rpa]or metatarsal! 
bones, or to the phalanges, though they may acquire 3> 
dary connections with bones of the tarsus or carpus, 
plan upon which they are arranged, when they oi-e most 
pletely developed, wdl be best understood by commenciiig 
with the study of their insertion in any one of tboae digits 
which possesses a complete set ; such, for example, as the 
fifth digit of the manus, or little finger, in Man and the 
higher Primoies. 

Oa the dorsal aspect this digit presents : first, attached to 
the base of its metacarpal bone, the tendon of a distiDCt 
muscle, the extensor carpi idnaris. Secondly, spreading oot 
ovei- the phalanges into an apon'eurosis, which is principallT' 
attached to the fii-st and second, is a tendon belonging to 
another muscle, the extettsor ■miniaii digiti. Thirdly, en' 
ing the same expansion is one tendon of the extenaor o 
mwma iUgitorwn, 

Oa tlie ventral aspect there are : first, attached to tiu) 
base of the metocarpsl, the tendon of a distinct muscle, the 
jlexor carpi ulnaris ; secondly, ^sing from the sides a 
ventral face of the metacarpal, and iuseited into either nSe 
of the base of the proiinial phalanx, two muscles, the mi 
assei ; thirdly, inserted into the sides of the middle phalani 
by two slips, a tendon of the_fe«ir perforaias ; and fourthly. 
passing between these two slips, and inserted into tli« b 



THE MUSCLES OF THE LIMBS. 53 

of the distal phah^px, a tendon of the flexor perforans. Thus 
there are special depressors, or flexors, for each segment of 
the digit. There appear, at first, to be but three elevators, 
or extensors, but, practically, each segment has its elevator. 
For the tendons of the extensor commwnis and extensor* 
mmimi digiti are attached to the middle and the proximal 
phalanges ; and the distal phalanx is specially elevated by 
the tendons of two little muscles, which, in Man, are 
usually mere subdivisions of the interosseif and pass upwards, 

Fig. 17. 




Fig. 17.— Part of the middle digit of the manus of an Orang with the 
flexors and extensors of the phalanges:— mcp., metacarpal bone; 
Ph. 1, PA. 2, Fh. 3, the three phalanges ; Ext. I, the deep long ex- 
tensor tendon from the extensor indicts ; Ext. 2, the superficial long 
extensor tendon from the extensor communis'^ I.e. the interosseous 
short extensor ; I.f. the interosseous short flexor ; F.pns. the deep 
long flexor (perforans) ; F.pts. the superficial long flexor (perforatus). 

joining the extensor sheath, to be finally inserted into the 
distal phalanx. 

The fifth digit of the pes, or little toe, sometimes pre- 
sents the same disposition of muscles, namely : 

On the dorsal aspect ; first, the peronoeus tertius for the 
metatarsal bone ; secondly, one tendon from the extensor 
digitanmi hrevis, but this last is commonly absent in Man ; 
thirdly, one tendon from the extensor digitorum lonqus. 

On the ventrdl aspect: iJrst, the perowBUs brem«, *dXX»R)cife^ 



54 THE ANATOMY OF VERTEBRATED ANIMALS. 

to the base of tlie metatarsal; secondly, two interossei; 
thirdly, a perfoi'ated flexor; and fourthly, a perforating 
flexor, like those of the manus. The divisions of the inter- 
ossei, which send tendons to the extensor sheath on the 
dorsum of the digits of the foot in Man, are hardly distinct 
from the ventral divisions of those muscles. 

In addition to the muscles which have been mentioned, 
the fifth digit has an (ibductor and an adductor, which may 
be regarded as subdivisions of the interossei, arising within 
the manus or pes, and inserted into opposite sides of the 
proximal phalanx ; and an opponens, a muscle attached to the 
ventral face of the carpus or the tarsus, and inserted into the 
post-axial edge of the shaft of the metacarpal or metatarsal. 

Finally, a lumbricalis muscle proceeds from the tendon 
of the perforating flexor, on the pre-axial side of the digit, 
to the extensor sheath. 

None of the other digits of the manus, or of the pes, has a 
greater number of muscles than this ; in fact, all the others 
have fewer muscles, some of those enumerated being sup- 
pressed. What are often regarded as muscles special to man, 
such as the extensor proprius indids and extensor minimi 
digiti, are only remains of muscles which are more fully 
developed in lower mammals, and send tendons to all four 
of the ulnar digits. 

Only the pollex has an opponens* Only the pollex and 
halliix have adductors and abductors. Some of the digits 
lack one or more of the ventral, or of the dorsal, muscles. 

The correspondence between the muscles which have been 
mentioned, at their insertion in the digits, is clear enough, 
but some difficulties present themselves when the muscles 
are traced to their ongins. 

In Man the flexors and extensors of the digits (except the 
interossei) of the fore limb, arise in part from the humerus, 
and in part from the bones of the forearm, but not within 
the manus. On the contrary, none of the flexors and ex- 
tensors of the digits of the pes arise from the femur, while 
some of them arise within the pes itself. The origins of 

* I have seen an opponens in the haWux. o? an Otan^. 



HE MUSCLES C 



the inueelea seem to be, da it were, higher up in the foi 
lini >> tlian in the hind linih. Nevartheleaa, Beveral of 
muscles coireepond rfiry closely. Thus, on the dorsal 
aspect, the extensor oun-i metacarpi poUicu paBses froi 
post-asial aide of the proximal region of the antebrachiwiu 
obliquely to the trapezium aJid the meta^jarpal of the pollex, 
just as its homologiie, the tibialig antieae, passes from the 
post-aiial side of the upper part of the leg to the ento- 
cuneiform and the base of the metatarsal of the hallus ; 
tlie two muscles correspond exactly. But the extensors of 
the phalanges of the pollex, and the deep BstanaorB of th^ 
other digits of the manua, arise on the same side of tli«j 
antebraehiimt, below the exteneor onaU Tnetaearpi polU 
while, in the leg, one of the deep estenaors of the hal 
and al] those of the other digits, arise atiil lower down, 
from the caloaneum. 

Not less reuiarkable is the contrast between the r 
Biiperficial seta of extensors in the two limbs. In the foi 
limb, proceeding from the pre-aiial to the post-axial 
the following extensor muscles arise from the external 
pre-asiaJ. condyle of the humerng ; the exteasor carpi 
alia hnufoa to the haee of the second metacarpal \ the esttt 
carpi radialU brems to the base of the third metacarpal 
exlensor eamimanis digUorum to the four ulnar digits; the* 
atengctr minimi digiti to the fifth digit ; the extensor earpi 
idnaria to the base of the fifth metacarpal. In the hind limb, 
there are no homologuea of the first two of these muscles. 
Ti» homologne of the extensor comnnmie is the long extensor, 
^~ ' " ' es, not from the femur, hut from the fibula. 

ut teriius,* passing- from iho dorsal face of the flbi 
1 metatarsal, is the only repreaentatiTe of 
•r cor^ ulnaris. 
\ the veatral aspect of the human fore limb, two c 
reloped in other Ma 



9 

tb<. I 





56 THE ANATOMY OF VERTEBRATED ANIMALS. 

flexors arise from tlie radius, ulna, and interosseous mem- 
brane, and run parallel with one another, though discon- 
nected, to the digits. These are, on the pre-axial side — ^the 
flexor pollids longus, to the distal phalanx of the pollex; 
and the flexor digitorum perforans, to the distal phalanges 
of the other digits. 

In the hind limb, two homologous muscles, the flexor lud- 
luds longus and the feasor digitorum perforans, arise from the 
tibia and flbula and interosseous membrane, and their ten- 
dons are distributed to the distal phalanges of the digits. 
But, before they divide, the tendons become connected to- 
gether in such a way, that many of the digits receive tendi- 
nous fibres from both sources. 

In the fore limb, there are no other deep flexors, but the 
internal, or post-axial, condyle of the humerus gives oiigin 
to a nimiber of muscles. These, proceeding from the pre- 
axial to the post-axial side, are the^jcor carpi radialis to the 
base of the second metacarpal ; the palmaris longus to the 
fascia of the palm, the flexor perforatvs digitorum to the 
middle phalanges of the four ulnar digits ; the fl>exor carpi 
ulnaris to the base of the fifth metacarpal. The sesamoid, 
pisiform bone is developed in the tendon of the last muscle. 

The only muscle which exactly corresponds with any of 
these, in the hind limb, is the plantaris ; which, in Man, is 
a slender and insignificant muscle proceeding from the outer 
(post-axial) condyle of the femur to the plantar fascia — and 
answers to the palmaris longus. In many quadrupeds, as 
the Rabbit and Pig, the plantaris is a large muscle, the ten- 
don of which passes over the end of the calcaneal process 
ensheathed in the tendo-achilliSf and divides into slips, 
which become the perforated tendons of more or fewer of 
the digits. The flsxor carpi radialis is also roaghly repre- 
sented by the tibialis posticus — a muscle which passes from 
the tibia and interosseous membrane to the entocuneiform, 
and therefore differs in insertion, as well as in origin, from 
its analogue in the fore limb. The flexor perforates digi- 
torum, of the foot takes its origin sometimes from the calca- 
jieum; sometimes, in part from the calcaneum, and in 



^■rt from the perforating flesor; or it maj be rlosely 
BKbnectcd with the tendone of the planiarig. The peroamv* 
Pi Luis repreeenta the flexor earpi ulnaris by its inaertioa, 
but it arieeH no higher than the fibula, and has no eesEunoid. 
Two moat important miiBcIes yet remain to be con- 
sidered in the leg. The one of these ie that which is in- 
serted bj the teiido-achillii into the oalcanenm, and ariaes 
l>y four beads, two from the condyles of the femur (called 
gtistrocnemiita), and two from the tibia and fibula (called 
«oJew«). The other muscle is the peronang longue, arising 
•from the fibula, paHHmg behind the external malleolus, and J 
-then croBBing the foot to the base of tho metatarsal of lie I 

The latter muscle does not appear to have any represen- 
:. [live in the fore limb. The gastroenemius and «)(ei« may 
1 .1 rsaibly represent the crural part of the perforated fleior, 
•iince in many of the Vertebrata, the tendo-achillia is but 
b«-iaely connected with the calcaneum, and passes over it i 
into the plantar fascia and the perforated tendons. A. I 
pecttliar adductor muscle of the hallux in Man and Apes ia 1 
the tranmersaHii ped!*, which is inserted into the basal I 
ihidauj of the hallus, and arises from the distal enda of 1 
:!]..■ metataraala of the otherdigita. The muscle Bometimes 1 
Usa an analogue in the manus. I 

^KBptectrieal Organn. — Certain fishes belonging to the genera I 
^^fpedo (amoDg the Elamiiobranehii], Gymnotan, Malap- I 
^BinM, and Momiyrtis (among the Teleostei), possess I 
^Buts vrhich convert nervous energy into electricity, just 1 
^^niucI«B convert the same energy into ordinary motion, I 
^^B therefore may well be mentioned in connection with I 
^H^ nervous system. The "electrical organ" is always J 
^^vposed of nearly parallel lamells of connective tissue, 1 
^^Hosing sDinll cbambei-B, in which lie what are termed the ■ 
^Ktrical pUitee. These are cellular stmcturea, in one facQ m 
^Hirhich the final ramifications of the nerves, which ar» I 
^K^ed to the organ by one or many trunks, are dis- I 
^Hfanted, The face on which the nci'ves ramify is in all] 



5f THE ANATOUY OF TXBTEBRATED ANIMALS. 

the plates the same, being inferior in Torpedo, where the 
lamellte are disposed parallel to the tipper aad lULder surfaces 
of the body; posterior in Oymnotms, and anterior in Malap- 
terurus, the lamellie being disposed perpendicularly to the 
axie in these two fishes. And this surface, when tbe die- 
chaise takes place, ia always negative to the other. 

Fig. 18. 




Fig IP.— The Torpedo, with Its eleotriosl appnralus displayed.—*, 
bninchis ; e, brwn ; e, electric organ ; p. cnmium ; m e, spinal nud : 
n, nervea to the pectoral fins ; nl, Btroi Uiterala ,- rp, branche* of 
the pneumogaBtrio nerves going to the eieotrio organ; o, eye. 

In Torpedo the nerves of the electrical organs proceed 
from the fifth pair, and from the " electric lobe " of the 
medidla oblongata, which appears to be developed at the 
origin o/ihejwieiiinogaBtrica. Tntte ottw e^ectiYialfiatea 



THE ENCEPHALON. 59 

the organs are supplied by spinal nerves ; and in Malapte- 
rwu8, the nerve consists of a single gigantic primitive fibre, 
which subdivides in the electrical organ. 

The ordinary Bays possess organs of much the same 
structure as the electrical apparatus, at the sides of the tail. 

Hie Nervous System: the Encephalon, — In all vertebrated 
animals except Amphioxus, the brain exhibits that separa- 
tion into Sifore-brainy mid-brain, and hind-brain, which results 
from its embryonic division by two constrictions, into the 
three thin-walled vesicles — ^the anterior, middle, and pos- 
terior cerebral vesicles — already mentioned. The cavities 
of these vesicles — ^the primitive ventricles of the brain — 
freely communicate at first, but become gradually dimi- 
nished by the thickening of their sides and floors. The cavity 
of the anterior vesicle is, in the adult human brain, repre- 
sented by the so-called third ventricle ; that of the middle 
vesicle, by the iter a tertio ad quartwm veiitriculum; that of 
the posterior vesicle, by ihe fourth ventricle. 

The floor and sides of the posterior vesicle, in fact, thicken 
and become the medulla oblongata ; together with the pons 
varolii, in those animals which possess the latter structure. 
The posterior part of the roof is not converted into nervous 
matter, but remains thin and attenuated ; the epend/yma, or 
lining of the cerebral cavity, and the arachnoid, or serous 
membrane which covers the brain externally, coming nearly 
into contact, and forming, to all appearance, a single thin 
membrane, which tears with great readiness, and lays open 
the cavity of the fourth ventricle. Anteriorly, on the other 
hand, the roof becomes converted into nervous matter, and 
may enlarge into a complex mass, which overhangs the 
posterior division, and is called the cerebellum. The pons 
varolii, when it exists, is the expression of commissural 
fibres, which are developed in the sides and floor of the 
anterior part of the posterior cerebral vesicle, and connect 
one half of the cerebellum with the other. 

Thus the hind-brain diflfers from the posterior ceT^bx^ 
vesicle in being' differentiated into the medoliiXa. o\A.OTi^^"a. 



' TEETEBRATED i 



{ormyeleacephalon)heUa(i,waA tte cerebellum witli the p 
varolii (wbicli together constitute tUemefeJwiepAa^'Un. trout ■ 




Fig, 19. — Diagrammttlic hotiaintnl section of i. \'ertebralo brain. Th» I 
tbllowinK letters serve for both this figure and Fig. 20 :— Jlffi, Mid- 1 
br&in. What liea in front of tliis Is the fure-braln, and wbmt &■■ 
behind, the hind-braio. Z,. 1. the lamina terminalis ; Off, the ri-l 
ftctory lobes: Htnp, the h em i spheres ; Th.E, the tbatuneiH- 

Shaloa ; Fn, the pinenl gland ; Pg. the pittiitary body ; FM, I 
iramen of Munto; CS, the corpus striatum ; Th, the opUo tL 
lam us ; CQ, ths corpora quadngemina ; CC, the crum cenMt I 
CT, the cerebellum; FY, tbe pons varolii; MO, the m-'-^ ■ 

oblongau: /, olfaotoril ; //, optloi; ///. point of exit fto 

brain of the motorea oculoruim ; /)', of the pathetici ; VI, at ttfll 
ftbducenles ; V-XII. origins of the other cerebral nervei. 1, rff 
toiy ventricle; S, tsteral ventricle; 3, third ventricle; 4, fbn 
ventricle; +, iter a tertiuad qvarttm seiitrictilum. 

The floor of the middle cerebral vesicle thicfaeiiB, a 
beoomes converted into two great bundles of longitodiadj 



THE ENCEPHALON. 



61 



fibres, the crura cerebri. Its roof, divided into two, or f om% 
convexities by a single longitudinal, or a crucial, depression, 
is converted into the "optic lobes," corpora higemina or 
quadrigemina. And these parts, the optic lobes, the crura 
cerebri, and the interposed cavity, which either retains the 
form of a ventricle, or is reduced to a mere canal (the 
iter a tertio ad quarttmi ventricuhmi), are the components 
of the mid-brain or mesencephalon. 

Fig. 20. 




Fig. 20.— A longitadinal and vertical section of a Vertebrate brain. 
The letters as before. The lamina terminalis is represented by the 
strong black line between FM and 3. 

The anterior cerebral vesicle undergoes much gi-eater 
changes than either of the foregoing ; for, in the first place, 
it throws out from its anterior lateral parietes two hollow 
prolongations, the hemispheres (or prosencephala), and each 
of these again protrudes from its anterior end a smaller 
hollow process, the olfactory lobe (or rhinencephalon). By 
the development of these processes the anterior vesicle 
becomes divided into five parts — one median and posterior, 
and four anterior and paired. The median and posterior, 
which remains as the representative of the greater part of 
the original anterior cerebral vesicle, is the vesicle of the 
third ventricle (or thalamencephalon). Its floor is produced 
into a conical process, the infundibulum, the blind end of 
which is connected with the pituitary body, or Fiajpoplv\j«ia 
eer^ri. Its sides thicken, greatly, acqmre a ^aaai^O'mft 



62 THE ANATOMY OF VEBTEBRATED ANIMALS. 

structure, and become the optic thalami. Its roof, on the 
other hand, resembles that of the fourth ventricle, in 
remaining very thin, and, indeed, a mere membrane. The 
pineal gland, or epiphysis cerehri, is developed in connection 
with the upper wall of the third ventricle ; and, at the sides 
of its roof, are two nervous bands, which run to the pineal 
gland, and are called its peduncles. 

The front wall of the vesicle, in part, becomes the so-called 
lamina terminalis, which is the delicate anterior boundary 
of the third ventricle. In certain directions, however, it 
thickens and gives rise to three sets of fibres, one trans- 
verse and two vertical — the former lying in front of the 
latter. The transverse fibres pass on either side into the 
corpora striata, and constitute the anterior corrnnissv/re which 
connects those bodies. The vertical fibres are the anterior 
pillars of the fornix, and they pass below into the floor of 
the third ventricle, and into the corpora mam/millaria, when 
those structures are developed. 

The outer and under wall of each cerebral hemisphere 
thickens and becomes the corpus striatum, a ganglionic 
structure which, from its origin, necessarily abuts against 
the outer and anterior part of the optic thalamus. The 
line of demarcation between the two corresponds with the 
lower lip (tcenia semidrcularis) of the aperture of communi- 
cation (called the /orameti ofMunro) between the third ven- 
tricle and the cavity of the cerebral hemisphere, which is now 
termed the lateral ventricle. In the higher Vert^ata, the 
upper lip of the foramen of Munro thickens, and becomes 
converted into a bundle of longitudinal fibres, which is con- 
tinuous, anteriorly, with the anterior pillars of the fornix 
before mentioned. Posteriorly, these longitudinal fibres are 
continued backwards and downwards along the inner wall 
of the cerebral hemisphere, following the junction of the 
corpora striata and optic thalami, and pass into a thicken- 
ing of the wall of the hemisphere, which projects into the 
lateral ventricle, and is called the hippocarnpus major. Thus 
a longitudinal commissural band of nervous fibres, extend- 
ingfrom. the £oor of the third ventricle to tViat oi tla.^ laler^l 



fibres, the emra eerebrL Its roof, dhided into two, or four, 
OQnvexities by a siiigle longhndmaL or a cmciaLdepvcaBioii. 
is conTerted into the "opdc lobes," corpom hi^emima or 
quadrigemina. And these parts, the optic lobes, the cnm 
cerebri, and the interposed caTitx. which either retains the 
form of a ventricle, or is redaced to a mere canal the 
iter a tertio ad quartum vemtnadum^r are the cc»np*3n£nts 
ot the mid-brain or meaemeepkaiom. 

Fig. 30. 




Fig. 20.— A longitadixial mad Totieal sectnm of a Tertebnte brain. 
The letters as before. The lawuna termimalis is represented by the 
strong black line between FMund 3. 

The anterior cerebral vesicle nndergoes mnch greater 

clianges than either of the foregoing ; for, in the first place, 

it throws oat from its anterior lateral parietes two hollow 

prolongations, the hemispheres (or prosencephala j, and each 

of these again protrudes from its anterior end a smaller 

hollow process, the olfadary lobe (or rhineneephalon), "By 

the development of these processes the anterior vesicle 

becomes divided into five parts — one median and posterior, 

uid four anterior and paired. The median and posterior, 

which remains as the representative of the greater part of 

the original anterior cerebral vesicle, is the vesicle of the 

third ventriele (or thalamencephalon). Its floor is produced 

into a conical process, the infundibidum, the bUnd end of 

which is connected with the pituitary body, or hypophysis 

cerebri. Its sides thicken greatly, acquire a ganglionic 



oeeipUal, and temporal lolies — wtile, on the outer aide of the I 
a/rpui striatum, a central lobe |Uie insula of Heil) lies a I 
the midst of these. The lateral Teatricleii are prolonged I 
intn the frontal, occipital, and tempond lobes, and acqnin I 
what are termed their anterior, posteri/yr, and d" 



Purthermore, while, in. the lower vertebratee, the tpurfaoe 
of the cerebral heniispherea ia aiaooth : in the higher, it be- 
comes complicated by ridges and fnrrows, the gyri and nuid, 
which follow particular patterns. The superficial vSiBCulK 
layer of connective tissue which covers the brain, and ii 
called pia mater, dips into these sulci : but the aracknoii 
or delicate serous membrane, which, on the one biuid, covere 
the brain, and, on the other, lines the cranium, passes from 
convolution to convolution without entering the sulci. Tl« 
dense periosteal membrane which lines the interior of the 
sknll, and is itself lined by the parietal layer of the arach- 
noid, goes by the name of the dm-a mater. 

The general nature of the modifications observable in Ih* 
brain as we pass from the lower to the higher niamraalia 
is very well shown by the accompanying figures of the brain 
of a Rabbit, a Pig. and a Chimpanzee ^Figs. 21 & 22). 

In the Babbit, the cerebral hemispheres leave the Offle- 
helium completely exposed when the brain is viewed inn 
above. There is but a mere rudiment of the Sylvian flsmit 
at 8y, and the three principal lobea, frontal (A), occipital (S\ 
and temporal (C), arc only indicated. The olfactory nerrw 
are enoruioua, and pass by a broad smooth tract, which 
occupies a great space in the lateral aspect of the biaia, 
into the natiform protuberance of the temporal lobe (C), 

In the Pig, the olfactory nerves and tract are hardly lesa 
conspicuous ; but the natiform protuberance is more aliar{d]' 
notched off, and begins to resemble the unciform gyroa in 
the higher jtfawimaiia, of which it is the homolog^e. The 
temporal gyri (C), though still very smaU, begin toenlai^ 
downwards and forwards over this. The upper part; of the 
cerebiul hemisphere is much enlarged, not only in tin 
frontal, but also in the occipital region, and to a great extent 




ig. 21.— toteral viewaof the braina of aKabliil, a Pig. and H Chim- 
panzee, drawn of ncnrly Ihe same alisolalB siie. The Rabbit's br»<n I 
a >[ lbetDp7 tbe Ple% in (lie middle, Uie Chiinpsn;tcc's, IsHeat 1 



liG THE ANATOMY OF VERTEBKATED 

01, iheolfBctory lolici ^., the rronlBllnbe-, B, the ciccipiuU lotHil 
CtheleraporallobB; J^.,thaSjlvianBB9iire; lit., the IqbuI«; S, Or, 
tupraorbilal ; S.F., M.J'., I.F., superior, TnidJle, and inferior ftiraal 
(Ori; A.P , aiitero-pnriclal ; P.P., pcialaro-pHrietnl By'; H, ral«« 
of aoUndo; F.Pl, pMtero-parielfll lobule; O Pf., cxiemal perlW- 
dioularor oecipito-tempnral sulcus; ,4«, anpilar e>'™s; 2.S,*.«* 
nectent ityri; A.T., M.T., P.T. the Ihrea temporal, and S.ft,. 
31.0c., I.Oc. ihc tlicee occipital gyri, 

hides ihe cerebeUum when the brain is viewed from abort 
What in the Babbit iraa a mere imgulation at I 
Pig has become a long buIcub — the Si/Juion, jt^eam, tb | 
lipa of which are formed by a gyrus, the Syio ion, or anyuhr, 
gyrus. Two other seta of gyri, more or leas parallel n" 
this, are visible npon the outer aurfaee of the bemigphtM; 
and at the entrance of the Sylvian fissure, at Zn, there is tt 
eleration which answers to the instiia, or central lohe. 

In the Chimpanzee, the oUactury nerves, or rather lobe^ 
are, i-elatively, very small, and the tracts which connect then 
with the uncinate gyri {subdantiix perforatcB) are completdj 
hidden by the temporal gyri (C). The Sylvian fiEanrB i> 
very long and deep, and begins to hide the inguJa, on wlud 
■A few fan-shaped, gyri are developed. The frontal lobee sn 
very large, and overlap the olfactory neiwea for a loiqf 
distance ; while the occipital lobe8_ completely cover and 
extend beyond the cerebellum, so as to~faide it coniplete|f 
from an eye placed above. The gyri and salci have now 
iittain^d an arrangement which is characteristic of all tht 
highest Manvmalm. The fissure of Bolando [R) divides tlrt 
antero-paiietal gyrus [A.P) fi-omthepostero-parietal {FS).m 
These two gyri, with the poetero-parietal lobule {P.PI,), tu 
part of the angular gyms [An), constitute the Parietal MtM 
The frontal lobe, which lies anterior to this, tie oociptfel lot».l 
which lies behind it, and the temporal lobe, which liett b ~ 
it, each present three tiers of gyri, which, in the ca.se of tl 
fi'ontal and occipital lobes, ai'C called superior, middle, audi 
inferior — ^in that of the temporal lohe, anterior, middkil 
iind posterior. The inferior eurface of the frontal lod*,,^ 
which hes on the roof of the orbit (S. Or.), preaenta nuun 
small sulci and gyri. 

On the inner face of the cerebral hemisphere (FJA^ 




Liul lu'mUplicrc6 ul' Die lialiiiit, 

;:hin>pBii£ee, ilrnivn ns bet'ori?, iiiiil plucoil in the some orilsr 
— flahe; C ir. oorpui (inlloEiun ; d.c, anleriorcommlsBHre ; 
— 1 _..... .,^^ unrinale; Jtf. merglniil; C, c»llo9»l (Hri , 



68 THE ANATOMY OF VEETEBEATED ANIMALS. 

the only sulcus presented by tlie Rabbit's brain is that 
deep and broad depression (H), which runs parallel with the 
posterior pillar of the fornix, and gives rise, in the interior 
of the descending comu of the lateral ventricle, to the 
projection which is termed the hippoca/mpus major. In 
the Pig, this hippocampal sulcus (H) is much narrower and 
less conspicuous ; and a marginal {M) and a caUosal {C) 
gyrus are separated by a well-marked calloso - marginal 
sulcus. As in the Rabbit, the uncinate gyrus forms the in- 
ferior boundary of the hemisphere. In the Chimpanzee, the 
marginal and callosal gyri are still better marked. There 
is a deep internal perpendicular, or occipito-parietal, sulcus 
{I.p). The calcarine sulcus (Ca) causes a projection into 
the floor of the posterior comu, which is the hippocampus 
minor ; while the collateral sulcus (Coll) gives rise to the emi- 
nence of that name in both the posterior and descending 
comua. The hippocampal sulcus (JS") is relatively insigni- 
ficant, and the lower edge of the temporal lobe is formed by 
the posterior temporal gyrus. 

In the Rabbit, the corpus callosum is relatively small, 
much inclined upwards and backwards; and its anterior 
extremity is but slightly bent downwards, so that the so- 
called genu and rosbmm are inconspicuous. The Pig's 
corpus callosum is larger, more horizontal, and possesses 
more of a rostrum : in the Chimpanzee, it is still larger, 
somewhat deflexed, and very thick posteriorly; and has a 
large rostrum. In proportion to the hemispheres, the 
anterior commissure is largest in the Rabbit and smallest 
in the Chimpanzee. The Rabbit and the Pig have a single 
corpus mammiUare, the Chimpanzee has two. The cere- 
bellum of the Rabbit is very large in proportion to the 
hemispheres, and is left completely uncovered by them in 
the dorsal view. Its median division, or vermis, is straight, 
symmetrical, and large in proportion to the lateral lobes. 
The flocculi, or accessory lobules developed from the latter, 
are lai'ge, and project far beyond the margins of the lateral 
lobes. The ventral face of the metencephalon presents 
on eaeh side, behind the posterior xdaTgni ol \>aft ^cyas 



THE MYELON. 69 

varolii, flattened rectangular areas, the so-called coi'pora 
trapezoidea. 

In the Pig, the cerebellum is relatively smaller, and is 
partially covered by the hemispheres ; the lateral lobes are 
larger in proportion to the vermis and the flocculi, and 
extend over the latter. The corpora trapezoidea are smaller. 
In the Chimpanzee^ the relatively stUl smaller cerebellum is 
completely covered ; the vermis is very small in relation to 
the lateral lobes, which cover and hide the insignificant 
flocculi. There are no coipora trapezoidea. 

In all the characters now mentioned the brain of Man 
differs far less from that of the Chimpanzee than that of 
the latter does from the Pig's brain. 

The Myelon. — The spinal canal, and the cord which it 
contains, are lined by continuations of the three mem- 
branes which protect the encephalon. The cord is sub- 
cylindrical, and contains a median longitudinal canal, the 
canalis centralis, the remains of the primitive groove. It is 
divided by anterior and posterior median fissures into two 
lateral halves, which are, usually, connected only by the 
comparatively narrow isthmus, which immediately sur- 
rounds the canalis centralis. The cord may, in the adult, 
extend through the whole spinal canal, or it may come to 
an end at any point between the caudal extremity and the 
anterior thoracic region. 

The distribution of the two essential constituents of 
nervous tissue, ganglionic corpuscles and nerve-fibres, is 
very definite in the spinal cord, ganglionic corpuscles being 
coidBned to the so-caUed " grey matter " which constitutes 
the isthmus, and spreads out into two masses, each of which 
ends in an anterior (or ventral) and a posterior (or dorsal) 
horn. Nerve-fibres also abound in the grey matter; but 
the so-caUed " white matter," which constitutes the external 
substance of the cord, contains only the fibrous nervous 
matter, and has no ganglionic corpuscles. 

The spinal nerves arise in opposite pairs from the two 
halves of the cord, and usually correspond in number with 



70 THE ANATOMY OE VEETEBKATED 

Fig. 23. 




w of the Chief Trunks of U 
^rvouB SysleiDB of Sa 

J of nalure). I. The miacioiy nerves. 

0. II. The optic n»rve. O. The eye. L. op. 



THE CESEBSAL NERVES. 71 

the chiasma, behind which lies the pituitary body. III. Oculomo- 
tor itu, IV, Fattuticus. Y. The trigeminal, m ith which the a6£fucf:>7» 
(VI.), facialis (Vll.), and the upper end of the sympathetic ( VS.), 
are closely connected. Branches of this nervous plexus are V.a, 
the nasal and ophthalmic branches of the fifth and the abdvcene. 
1 ', by Cj d, the palatine, maxillary, and mandibular branches of the 
fifth. V, e, the tympanic branch into which the proper facial nerve 
( VII.J enters, and, with a brancli of the vagus, forms the so-called 
facial nerve of the Frog, F. VIII. The auditory nerve. X., with 
its branches Xi, JT^, X*, X*, represents the glossopharyngeal and 
the vagus. The medulla oblongata (^Myelencephalon) ends, and the 
medulla spinalis {Jdyelon) begins, about the region marked by the 
letter M, M 1-10, the spinal nerves. M 2, the brachial nerves, 
M 7, 8, 9, the ischiatic plexus, from which proceed the crural 
(N. c.) and ischiatic (N. a.) nerves. S. The trunk of the sympa- 
thetic. S.M. The communicating branches with the spinal ganglia. 
S I-IO. The sympathetic ganglia. 

:lie vertebrae through, or between, which they pass out 
Fig. 23). Each nerve has two roots, one from the dorsal, and 
ane from the ventral, region of its half of the cord. The 
former root has a ganglionic enlargement, and only con- 
Dains sensory fibres ; the latter has no ganglion, and ex- 
slusively contains motor fibres.* After leaving the vertebral 
canal, each spinal nerve usually divides into a dorsal and a 
ventral bi'anch; but, in the Ganoid fishes, each of these 
branches is a distinct nerve, arising by its own proper roots. 

Tlie Cerebral Nerves. — The greatest number of pairs of 
nerves ever given off from the vertebrate brain is twelve, in- 
cluding the so-called oKactory nerves, and the optic nei*ves, 
vhich, as has been seen, are more properly diverticula of 
the brain, than nerves in the proper sense of the word. 

The olfactory "nerves" (olfactmnij constitute the first 
oair of cerebral nerves. They always retain their primary 
3onnection with the cerebral hemispheres, and frequently 
3ontain, throughout life, a cavity, the olfactory ventricle, 
sv^hich communicates with the lateral ventricle. 

The optic " nerves " fopticij are the second pair of cere- 
bral neives. In the Lampreys and Hags (Marslpobranchii) 
liese nerves retain their embryonic origin from the thala- 

* Amphloxua appears to be an exception to this, as to most other, 
rules of Vertebrate anatomy. 



^ THE ASATOITT OF VEETEBBATED AJTmjlI^. 

meDcepbaion, and each goes to the eje of it« < 
In other Veriebrala, the nerrea cross one tmoUier at lb 
base of the bf&in iTtleiateij, or are fosed tc^ctber iatot 
ekMUiaa f^Gaiundei, Elaiimobranekii, and all the higher Virtl- ii 
hratoj. Ii]thchigherF«^bnita,ag3iii,theEbresof theoptil 
nerres become connected chieflj with the xaesencephalou, 

An the other cerebral nerves differ from these in aridsg; 
not as divertiimla of anj of the cerebral reaicles, but bj 
histological difiereutiation dt the prinutiTe brain-case, or i| 
laatina dorsalea at the BknU. 

The third (motore» ocuhrumj and ff/urth fpatheticij [ 
of nerves are distribnted to the muHcles of the eje; tbs | 
third to the m^ority of these mnsclea, the fourth to th$ 
saperior obliqae mnscle^ The third pair of nerves ii 
trmn the cmra cerebri, or inferior division of tbe metes' 
cephalon, npon the base of the brain ; the fourth pair, trma. 
the forepart of the npper dirieioii of the metencephalcoi 
immediate^ behind the optic lobes, npon ihe sopeniff 
anr&ce of tbe brain. This region is known as the Valve of 
Vieiuaetts in the Mammalia. 

All the other cerebral nerres originate in the poitteriat 
division of the htTid-bram — the mjelencepkolon. The great 
fifth pair (tri^eminij passes ont from the sides of the n 
cephalon, and supplies sensory nerves to the intcgnment at 
the head, and motor nerves to most of the mnsclee of IJ 
jaws, by ite three divisions — the ophllmlmie, the tu/perior 
maasSlary. and the inferior maxillary, t 

Of these divimons the two latter are, very genemUf, 
closely connected together, while the ophthalmic divisioil 
remains distinct. The ophthahnic division passes to tbs 
cleft between the trabecula and tbe maxillary process (whid 
nearly corresponds with the orbit, and might be termed the 
OTbitfi-natal cleft), and is dietribnted to the inner and tlif 
nuter iiide of that cleft. Hence its main biunchea a 
iind lachrymal. The two maxUlary nerves, on the otlier 
band, arc distribnted to the inner and outer s 
rior and pogtcrior Ixiuudaries, of the buccal cleft. HenM' 
the superior maxillary belongs to the posterior, i 



THE CEBEBSAL NEBYES. 73 

side of the maxillary process, while the inferior maxillary 
appertains to the anterior region of the first visceral arch. 
The superior maxillary commonly unites with the outer, 
or lachrymal, division of the ophthalmic ; the inferior maxil- 
lary with the anterior division of the facial. 

In the higher Vertehrataf the trigeminal nerve usually 
has two very distinct roots, a dorsal sensory, provided with 
a ganglion (the Casserian ganglion), and a ventral motor, 
non-ganglionated. The fibres of the latter pass almost ex- 
clusively into the inferior maxillary division. In addition, 
the ophthalmic division may have a ganglion (ciliary) ; the 
superior maxillary another (sphenopalatine or Meckelian), 
and the inferior maxillary a third (otic). 

The sixth pair (abducentesj issues from the inferior sur- 
face of the brain, at the junction of the myelencephalon 
with the metencephalon. It supplies the external straight 
muscles of the eye; with the muscles of the nictitating 
membrane, and the retractor hulhi, or m/asculus choanoides, 
when such muscles exist. 

The seventh pair ffadalesj supplies the superficial facial 
muscles, and ultimately divides into two branches, one of 
which is in relation with the mandibular, and the other with 
the hyoidean arch. 

The five nerves which have just been mentioned are often 
intimately connected together. Thus, in the Lepidodren, 
the three motor nerves of the eyeball are completely fused 
with the ophthalmic division of the fifth.* In the Myxinoid 
fishes there are no motor nei'ves of the eyeball ; but, in the 
Lamprey, the rectv;8 extemus and inferior , and the obliquus 
inferior, are supplied by the ophthalmic, while the oculo- 
motor and the pathetic unite into a common trunk, which 
gives branches to the rectus superior and intemus, and 
obliquus superior. The oculomotor, the pathetic, and the 

• lamgreatlydisposedtothink portions of the nerves of the or- 

that the motor nerves of the eye bito-nasal cleft, the third and 

more nearly retain their primary fourth appertaining to the inner 

relations in Leptdosiren than in division of the ophthalmic^ thfi 

any other vertebrated animal ; sixth to its outei dVvVsvoTL, 
snd that tbey are really the motor 



74 THE ASATOMT OP VEBTEBEATED ANIMALS. M 

abduc«na, are more or lesa confounded with, the ophthalmic 
in the Amphibia ,- but in Teleoetei, Qanoidei, Elofmobran^ii, 
and in all the higher Vertebrata, the nervea of the muscles 
of the eje are dietinct from the fifth pair, eicept where the 
oculomotor unitea with the ophthalmic into the cilJuiT 
ganglion. 

The facial and the trigeminal nerres have ctimmon rooU i 
in fiahea. In A^iyphibia, though the roota are distinct, the , 
facial may be completely united with the ganglion of the 
trigeminal, ae in the Frog. In all abranchiate Yertebntk i 
the two mervea are quite distinct. i 

Whether the nerrea are distinct or not, a palatine, at 
vidian, nerve (which, in the higher Vertebrata, ia espcciallj i 
connected with the facial) runs through, or bemaith, tls i 
base of the skull, parallel with its long axis; and, aftet 
vinjting with the superior maxillary, and usually eontri- 
buting to form the sphenopalaHne, or Meekelia'n. ganglion, is 
distributed to the mucous membrane of the roof of the 
mouth; and the mandibular division of the seventh, or 
chorda tympani. unites with tlie inferior maxillary divisiiui 
of the fifth nerve. 

The eiglUh pair fatiditoriij is formed by the nerves of tli« 
organ of hearing. 

The mntk pair fghsgopharyngeij ia especially distributed 
to the pharyngeal and lingual regiona of the alimentaif 
canal, and, primarily, supplies tlie boundariea of the second 
visceral cleft. 

The tenth pair ('pneujaogoBtrici or vagi) consista of very 

I remarkable nerves, which pass to the gullet and stomaok. 

I the respiratory and vocal organs, to some parts of the 

' int^ument of the body, and to the heart. In the leklkyop- 

sida they give off, in addition, long lateral nerves to the 

integuments of the sides of the body. In the higher VerU- 

braia, these lateral uei-ves are represented only by smiB 

branches distributed chiefly to the occipital region. Tfc( 

ninth and tenth pairs ai-e both motor and aenaory in fuM- , 

'W>, and are often ao intimately connected aa to form tdmot 



THE EXITS OF THE CEBEBSAL NERVES. 75' 

The eleventh pair faccessoriij are cerebral only by courtesy, 
as these nerves take their origin from the spinal cord, by 
roots which issue between the proper anterior and posterior 
roots of the spinal nerves, and, joining together, form, on 
each side, a nerve which passes out with the pneumogastric, 
partly joining it, and partly going to muscles which arise 
from the head and anterior vertebrae, and are inserted into 
the pectoral arch. 

The spinal accessory exists in no Ichthyopsid vertebrate, 
but is found in all Sati/ropsida, with the exception of the 
Ophidia, and in the Marmnalia. 

The twelfth and last pair fhypoglossij are the motor nerves 
of the tongue, and of some retractor muscles of the hyoidean 
apparatus. 

In the Ichthyopsida the first cervical nerve supplies the 
distributional area of the hjrpoglossal ; but in all the abran- 
chiate Vertehrata there is a hypoglossal, which traverses a 
foramen in the ex-occipital, though it often remains closely 
connected with the first cervical, and may rather be re- 
garded as a subdivision of that nerve, than as a proper 
cerebral nerve. 

Thus the nerves arising from the hind-brain, in all the 
higher Vertehrata, fall into three groups: 1st, a sensori- 
motor, pre-auditoiy, set (3rd, 4th, 5th, 6th, 7th) ; 2nd, the 
purely sensoiy auditory nerve (8th) ; 3rd, the sensori-motor, 
post -auditory, set (9th, 10th, 12th). 

The apertures by which several of these nerves leave the 
skull, retain a very constant relation to certain elements 
of the cranium on each side. Thus : 

a. The filaments of the olfactory nerve always leave 
the cranium between the lamina perpendicularis, or body 
of the ethmoid, and its lateral or prefrontal portion. 

h. The optic nerve constantly passes out behind the 
centre of the orbitosphenoid and in front of that of the 
alisphenoid. 

c. The third division of the trigeminal, or fifth nervcj, 
always leaves the skull behind the centre of the aliai^hftTiovC 
and in front of the pro-otic. 



76 THE ANATOMY OF VERTEBRATED ANIMALS. 

d. The glossopharyngeal and pneumogastric always make 
their exit behind the centre of the opisthotic, and in front 
of the centre of the ex-occipital. 

The apertures for the exit of the cranial nerves denoted 
in the paragraphs, a. 6. c. d., when surrounded by bone, and 
well defined, are called respectively : a, the olfactory foramem, ; 
6, the optic foramen ; c, the foramen ovale ; d, the foramen 
lacerum jposterius. The adjacent bones may take equal shares 
in bounding these foramina, or the foramina may be alto- 
gether in one bone ; but their positions, as here defined, 
never change. 

Another point to be especially considered respecting the 
general disposition of the cranial nerves, is the relation 
which some of them bear to the visceral arches and clefts, 
and which has already been incidentally mentioned. Thus, 
the seventh nerve is distributed to the posterior part of the 
first visceral arch, and to the anterior part of the second 
visceral arch, its two branches inclosing the first visceral 
cleft. In like manner, the ninth (glossopharyngeal) nerve 
is distributed to the hinder pai't of the second arch and to 
the front part of the third, its branches inclosing the 
second visceral cleft. The first branch of the pneumo- 
gastric has similar relations to the third and fourth arches 
and to the third cleft; and in branchiate Vertehrata, the 
other anterior branches of the pneumogastric are similarly 
distributed to the successive branchial arches, the two divi- 
sions of each branch inclosing a branchial cleft. 

The second and the third divisions of the trigeminal are 
distributed, in an analogous manner, to the anterior region 
of the first visceral arch, and to the posterior or outer 
region of the maxillo-palatine process — the gape of the 
mouth representing a visceral cleft between the two. The 
inner and outer portions of the first division of the tri- 
geminal are similarly related to the inner, or anterior, 
region of the maxillo-palatine process, and the outer side 
of the trahecula cranii — the orbito-nasal fissure representing 
the cleft between the two. 
Considerationa of this kind suggeat t\iat t\i^ iTc^fe^Ml^ 



THE SYMPATHETIC NERVES. 77 

and the maxillo-palatine processes may represent pre-oral 
visceral arches, which are bent forward ; and, in the case of 
the trabectdoe, coalesce with one another. Such an hypothesis 
would enable us to understand the signification of the naso- 
palatine canal of the Myxinoid fishes, which would be simply 
the interspace, or passage, between the trabeculsB (which 
most have originally existed if ever they were distinct 
visceral arches) not yet filled up ; and the anomalous process 
of the roof of the oral cavity, which extends towards the 
pituitary body in the embryos of the Vertebrata in general, 
might be regarded as the remains of this passage. 

On this hypothesis, six pair of inferior arches belong to 
the skull — ^namely, the trabecular and maxillo-palatine, in 
front of the mouth ; the mandibular, the hyoidean, and two 
others (first and second branchial), behind it. For, as there 
are three cranial nerves embracing the first three visceral 
clefts which lie behind the mouth, there must be four 
post-oral, cranial, visceral arches. 

Supposing that the occipital segment in the brain-case 
answers to the hindermost, or second branchial, cranial, 
visceral arch, the invariable attachment of the proximal 
ends of the mandibular and hyoidean arches to the auditory 
capsule leads me to assign the parietal and the frontal 
segments to the maxillo-palatine and trabecular visceral 
arches. And thus the ossifications of the auditory capsule, 
alone, are left as possible representatives of the neural 
arches of the three anterior post-oral visceral arches. 

But these speculations upon the primitive composition of 
the skull, however interesting, must not, as yet, be placed 
upon the same footing as the doctrine of its segmentation, 
which is simply a generalisation of anatomical facts. 

The Sympathetic, — A Sympathetic Nervous System has 
been observed in all the Vtrtehrata except Amphioxus and 
the Marsipobranchii, It consists, essentially, of two longi- 
tudinal cords, placed one upon each side of the inferior 
face of the cranio-spinal axis. Each cord receives coTooixsL- 
nicatio/^ £breB from the spinal nerves of its o^im. «vi<&, ^scA', 



78 THE ANATOMY OP VBETEBBATED ANIMALS. I 

when complete, from all the cranial nerves eieept those of 
the apecjal senses of houring, sight, and smell — the Ti " 
nerves constituting the anterior terminations of the sympa- 
thetic cords. At the points of commonication gajiglia 
developed, and the nerves which emerge from these ganglia 
are distributed to the mueclea of the heart and veaaela, and 
to those of the viscera. These peripheral nerves of the 
sympathetic system frequently present sniaU ganglionJO 
enlargements. 

In the Marsi/iobronchii, the place of the sympathetic 
appears to he takeji.toagreateitent.hjthepneumogaBtric! 
ind, in Mymine, the two pnemnogastries unite upon the in- 
testine, and follow it, as a single trunk, to the 

The SeiiBory Organs. — The organs of the thr-ee highs 
aensea— Smell, Sight, and Hearing — are situated, 
been already described, in pairs, upon each side of the akoll, 
in all vertehrat* animals eicept the lowest fishes ; and, ill 
their earliest condition, tliey are alike involntione of tka 
integument. 

The Olfactory Apparatus acquires no higher complication 
than thia, being either a single sac (A7nphioxua (Pj 
branehii), or, more commonly, two, the anrfacea of wiJdii 
are increased by plaiting, or by the development of torlniid 
cartilages, or hones, from the lateral poitions of the eth- 
moid. Upon these, nervous filaments arising from the oUai^ 
tory lobe of the brain are disti-ihiited. The cavities of Vbt 
olfactory sacs may be placed in communication with Hulk 
of the mouth hy the nasal passages ; or, aa i 
majority of fishes, they may have only an eitemal aperttm 
or apertures. 

In Beptiles, Birds, and Mammals, a peculiar nasal ghtni 
ia fi'equentJy connecfed with, and pours its secretion into, 
each olfactory chamber. 

The/ornimno iticieiva. loft between the premaiiUajies aai 
the palatine plates of the maiiUaries in Mammalia, 
sometimes closed by the mucous membranes of the nasal 
ss, and sometimes not. In the latter case 



THE EYE. 79 

are the canals of Stenson, and place these two cavities in 
communication. Glandular diverticula of the mucous mem- 
brane, supplied with nervous filaments from both the 
olfactory and the fifth pair, may open into these canals. 
They are called, after their discoverer, the " organs of 
Jacohson" 

The Eye is formed by the coalescence of two sets of 
structures, one furnished by involution of the integument, 
the other by an outgrowth of the brain. 

The opening of the integumentary depression which is 
primarily formed on each side of the head in the ocular 
region becomes closed, and a shut sac is the result. The 
outer wall of this sac becomes the transparent cornea of 
the eye; the epidermis of its floor thickens, and is meta- 
morphosed into the crystalline lens ; the cavity fills with 
the aqueoiLs humour. A vascular and muscular ingi*owth 
taking place round the circumference of the sac, and, 
dividing its cavity into two segments, gives rise to the iris. 
The integument around the cornea, growing out into a fold 
above and below, results in the formation of the eyelids, and 
the segregation of the integument which they inclose, as 
the soft and vascular conjtmctiva. The pouch of the con- 
junctiva very generally conmiunicates, by the lachrymal 
duct, with the cavity of the nose. It may be raised, on its 
inner side, into a broad fold, the nictitating membrane, moved 
by a proper muscle or muscles. Special glands — ^the lachry- 
mal externally, and the Ha/rderian on the inner side of ^he 
eyeball — ^may be developed in connection with, and pour 
their secretion on to, the conjunctival mucous membrane. 

The posterior chamber of the .eye has a totally distinct 
origin. Very early, that part of the anterior cerebral vesicle 
which eventually becomes the vesicle of the third ventricle, 
throws out a diverticulum, broad at its outer, and narrow 
at its inner end, which applies itself to the base of the in- 
tegumentary sac. The posterior, or outer, wall of the diver- 
ticolum then becomes, as it were, thrust in., axLd ioxc^^ 
towards the opposite wall, hy an ingrowth, oi t\Le «A^2JC«ii\. 



80 THE ANATOMY OF VERTEBEATED ANIMALS. 

connective tissue ; so that the primitive cavity of the diver- 
ticulum, which, of course, communicates freely with that of 
the anterior cerebral vesicle, is obliterated. The broad end of 
the diverticulum acquiring a spheroidal shape, while its 
pedicle narrows and elongates, the latter becomes the optic 
nei-ve, while the former, surrounding itself with a strong 
fibrous sclerotic coat, remains as the posterior chamber of 
the eye. The double envelope, resulting from the folding 
of the wall of the cerebral optic vesicle upon itseK, gives 
rise to the retina and the choroid coat: the plug, or in- 
growth of connective tissue, gelatinises and passes into the 
vitreous humour , the cleft by which it entered becoming obli- 
terated. 

Even in the higher Vertehrata the optic nerve is, at first, 
connected exclusively with the vesicle of the third ventricle, 
and makes no decussation with its fellow. But by degrees 
the roots of origin of each nerve extend over to the opposite 
side of the brain, and round the thalamus, to the mesen- 
cephalon on that side, and the trunks of the two nerves 
become intermixed below the third ventricle, in a close and 
complicated manner, to form a chiasma. 

In Amphioayus and Myxiney the eyes are very imperfectly 
developed, appearing to consist of little more than a rudi- 
mentary lens imbedded in the pigment, which encloses the 
termination of the optic nerve ; and in Myxine, this rudi- 
mentary eye is hidden by muscles and integument. It ap- 
pears doubtful whether in these fishes, and in the Lampreys, 
the eye is developed in the same way as in other Vertehrata. 

In all other Vertehrata, the eyes have the typical structm^e, 
though sometimes, as in the Blind-fish {Artiblyopsis) and the 
Mole, they have no functional importance. In the Ichthy- 
opsida and SaiJi/ropsida, but not in Mammalia, the sclerotic 
is often partially ossified, the ossification usually forming a 
ring around its anterior moiety. It becomes enormously 
thickened in the Cetacea. 

Except in Amphioxvs and the Myxinoid fishes, the eye- 
ball is moved by six muscles ; of these, four, proceeding 
from the interior of the orbit to the periphery of the eye- 



THE EAB. 81 

ball, and erarrounding the optic nerve, are termed superior, 
inferior, internal, and external recti. The other two are 
connected with the npper and the lower margins of the 
orbit respectively, and pass thence to the outer side of the 
bulb. These are the mpenor and -the inferior obliqui. In 
many Reptiles and Mammals a continuous funnel-shaped 
sheet of muscle, the m/usmltis choanoidea, Hes within the four 
rectif and is attached to the circumference of the posterior 
moiety of the baU of the eye. It would appear, from the 
distribution of the nerves, which has already been described, 
that the rimscuLus choanoideSf the external rectvs, and the 
nictitating muscle, constitute a group of eye-muscles mor- 
phologically distinct from the other three recti, the ohliqui, 
and the levaior paJ^hroe superioris. In many Reptiles, and 
in the higher Vertehrataj the eyelids are closed by circular 
muscular fibres, constituting an orbicularis palpehrarwm, 
and are separated by straight fibres proceeding from the 
back of the orbit, usually to the upper eyelid only, as the 
levator palpebroe superioris; but sometimes to both lids, 
when the lower muscle is a depressor palpebroe inferioris. 

The Harderian and lachrymal glands are not found in 
fishes; but the former is met with in the Batrachia, and 
both are of common occurrence in the Satt/ropsida and 
Mammalia. 

In LacertUia, Crocodilia, Aves, and many Fishes, a pecu- 
liar vascular membrane, covered with pigment, like the 
choroid, projects from near the entrance of the optic nerve, 
on the outer side of the globe of the eye, into the vitreous 
humour, and usually becomes connected with the capsule 
of the lens. This is the pecten, or marsvpivmi. 

The Ear, — The first rudiment of the internal ear is an 
involution of the integument into a small sac, which is 
situated on each side of the posterior cerebral vesicle, just 
above the end of the second visceral cleft. The mouth of 
the involution soon closes, and a shut sac results. The sac 
enlarges, and, by a remarkable series of changes, \t& m^^^c 
part becomes (ordinarily) converted into three aetaxcwcublwiv 

a 



82 THE ANATOMY OP VEBTEBRATED ANIMALS. 

canals — the anterior and posterior vertical, and the external 
or horizontal canals of the memhranoiLs labyrinth. The body 
of the sac remains, for the most part, as the vestibule; but a 
caecal process, which eventually becomes shut off from the 
vestibule, is given off downwards and inwards, towards the 
base of the skull, and is the rudiment of the scala media of 
the cochlea. This may be called the membranous cochlea. 

In the anomalous vertebrate, Amphioxus, no ear has yet 
been discovered. The Hag (Myxine) has only one, and in 
the Lampreys (Petromyzon) there are only two, semicircular 
canals ; but, in fishes in general, all three are developed, 
and it is a question whether the cochlea is not also repre- 
sented. 

In fishes, the periotic cartilage and its ossifications in- 
close this membranous labyrinth, externally, and present 
no merely membranous gaps, or fenestrce, towards the first 
visceral cleft, or the space which represents it. 

But in higher Vertebrata {Amphibia, Savropsida, Mam- 
malia), in which the membranous labyrinth is always in- 
closed within a complete bony periotic capsule, the outer 
wall of this capsule invariably remains unossified over one 
or two small oval areae, which consequently appear like 
windows with membranous panes, and are termed the 
fenestra ovalis and the fenestra rotunda. 

The fenestra ovalis is situated in that part of the periotic 
mass which bounds the chamber containing the membranous 
vestibule externally ; and it is always found that when both 
the pro-otic and the opisthotic bones exist, they contribute 
nearly equal shares to the formation of its boundaries. In 
fact, the fenestra ovalis is situated in the line of junction of 
these two bones. The fenestra rotwnda, on the other hand, is 
below thefenestra ovalis, and lies altogether in the opisthotic. 
It forms part of the outer wall of the cavity in which the 
membranous cochlea is lodged. 

In the Sauropsida and Marrvmalia, this membranous 
cochlea, become fiattened and bandlike, and its communi- 
cation with the vestibule obliterated, is lodged in a conical 
cavity, in such a manner as to divide \\ia.t ca:TL\rj m\/i \j^q 



THE EAB. 83 

called scalcBf wliich only communicate at their 
rHe base of the one scala, called scala vestibuli, 
the cavity which contains the membranous vesti- 
t of the other, scala tynvpani, abuts against, and is 
stopped by, the membrane of the fenestra rotunda. 
;y of the membranous cochlea stretched between, 
Ing to divide, these two scaloe, is called the scala 

>tiles, Birds, and Omithodelphous Mammals, the 
i only slightly bent or twisted upon itself. But, in 
T MamvmaMa, it becomes coiled in a flat or conical 
one-and-a-half {Cetacea, Erinacem) to five {CcbIo- 
a) turns. 

mbranous labyrinth is filled with a clear fluid, the 
I, and usually contains otolithes of various kinds, 
the membranous labyrinth and the walls of the 
the periotic mass in which it is contained, lies 
tear fluid, the 'perilymph, which extends thence into 
vestibvZi and tynvpani. 

mimals which possess a fenestra ovalis, its mem- 
es attachment to a disc, whence an ossified rod, 
Toceeds. Where the former structure obtains, as 
nost Reptiles, and some Amphibia, the bone is com- 
led colv/mella av/ris; when the latter, as in most 
, stapes. But there is really no difference oi, im- 
jetween stapes and colwmella, and it is advisable to 
rmer name for the bone under all its forms. 
majority of Vertebrata of higher organization 
9, the first visceral cleft does not become wholly 
i, but its upper part remains as a transversely 
cavity, by means of which the pharynx would be 
communication with the exterior, were it not that 
te sides of the canal grow together into a mem- 
uiition — ^the Tnerribrana tympani. So much of the 
es external to this is the external auditory meatus ; 
b lies internal to it, is the tympanwm, or drum of 
ad the Ihista>chian tube, which places the tympa- 
mmmiication with the phar3mx^ While the outer 



bi 1 

wall of the tympanum ia the tjTiipaiiic memhrane, its inner 
wall is the periotic maaa with its ^fene$t^<B ; and, in »11 
Vertehraia below MaminalB, the out<3' end of the atapet is 
either free, or, more commonly, is flied to the tympanic 
membrajie, and tlius the latter and the membrane of tbx ' 
fenestra ovalU become mechanically connected. In all these ' 
animals the mandible ia connected with the skull by the 
intermediation of an ob quad/ratum. 

But, in the Maminalia, the mandible is ai-ticulated directlj 
with the sqnamosal, and the qvadratum is converted into 
one of tiie so-called os^cula audUAs, and named the malltiu. 
The malleus becomes attached to the tnemhrana tympmu, 
by a apecial proeesB ; while its otber extremity, which wu 
continuous with Meckel's cartilage in the embryo, is con- 
verted into the proeesaua gracUU, or Foliantig, and lice b 
tween the tympanic, the squam.osal. and the periotic bonet 

In the singular lizard Sphenodtm [A, Pig. 24), the antenv 
oomu of the Lyoid is continuous with the distal end of die 
stapes, aiid the latter sends a cartil^inous process npwai^ 
which passes into the wall of the periotic capsole, juat bo- 
hind the proximal end of the os quadralwn,. Thus the stapei 
stands out at right angles to the hyoid comu, and the latter 
becomes divisible into a sa^a-stapedial part, and a part 
which lies below the stapes, and answers to the styloid 
process, or atylohyal, of the Mdntnutlia. The supra-8tq)e- 
dial part is represented by cartilage, or ligament, in otliet 
Sauropeida, but seems not to ossify. In the MammaUt 
(B, Pig. 24) the snpra-atapedial part ossifies, becomea the 
iiieu«, and its proiimal end is usually articulated by > 
synovial joint with the mtdleug ( = guadratuiii). A. ^'MiTHtt 
ossification, the os wbiettlaTe, usually arises at that put 
of the hyoidean cartilage in which the stapes and the Hum 
unite. That part of the hyoidean cartilage which is coaraUi 
into the styloid process is generally connected with the ortie* 
tare by muscular fibres, which constitute the atapediut tavtok 
On the other band, the posterior, or short process of the mo^i 
is connected by ligament with that part of the periotic mflt 
into which the styloid process is directly continued, a^0 



S" THE VISCERAL AECHES. 

i3 hard to say whether the styloid part of the hyoid is ■ 
tinued into the inens by these ligamenta or by the etapedim, J 
But, howerer this may he, the maiieiw and the ineaa are thfl 
pruximal ends of the mandibular and hyoideaa wchea 
respectirely. 

In OBseooH fishes (0, Pig, 24). which have no fenestra oi 

or stapes, the siipra-stapedial part of the hyoid becomes ti 

large bone — the hyamartdibulm: On the other hand, tbc 

proximal eiti-emity of the quadrate cartilage atrophiea 

Fig. S4. 

-i*r,J 




Fig. 24.-Dia.grtai of the skeleton of the first and s 

ar'^hei in a Lizard (A], a Mammal [B), and no OaBeona Fish (C). 

Tbe skeleton of (be Snt vlaoeTa! arch it shaded, tlial of the aefond b 
left nearly unshaded. 7. Fint yiaceral arch. Met. Meckel's car- 
ti1a(^. Art. A.rticu1are- Qh, Qaadratam. Mpl. Metaptcrygoid ; 
JU. MalleUB; p.ff., Prooeisui graoilia. II. Second viaoorftl aroh, 
Hy. Hyoidean eoma. Si. JI. Sniohyal. 8. StapedinB, Stp. Stapei, 
5. Sfp. Snpra-atapedisl. HM. Byomandibulnr. Theamnrindicates 
iheBratTiseeralcleft. Pc. The periotle cnpaale. Pljp. The pterygoid, 

'As direct connection with the poriotic caj«ule, and beeomea 
^^stincUy ossified, as the ■meiapierygoid. In the Sharks, 
^Kkh tbe ascending, mctapteiygoid, part of the quadrate. 
^Boet. 

^^pTbe qtittdrate and anpra-stapedial portions of the firat 
,' and second visceral arches coalesce in the ChvBUEra, Dipnoi. 

ind many An^hSiia, into a single cartilaginouB plati;. 

In the Mammalia, and to some extent in Aires, oBsentte 

matter is deposited in the fibrons tissue which suiTOunds 

the sides and hose of the tympanic membrane, and gives 

, .lia&ta ft ■qj^i"! fyn^antc bone. In most Maia^ialia, oasifi- 



86 THE ANATOMY OP VEETEBBATED ANIMALS. 

cation extends into the sides and floor of the tympanum 
and external meatus; and a process of integument, chiefly 
derived from the second visceral arch, is converted into a 
concha^ or external ear. 

The Organ of Taste is the mucous membrane which covers 
the tongue, especially its posterior region, and probably also 
a part of that lining the fauces. When the sense is well 
developed, the mucous membrane is raised into numerous 
papillae of various forms, and is well supplied with filaments 
from the glossopharyngeal nerve. 

The sense of Touch is diffused over the integument and 
over the mucous membrane of the buccal cavity, which is, 
strictly speaking, a part of the integument. 

As special organs of touch in the higher Vertehrata, the 
nervous papillae, containing " tactile corpuscles/' and the 
long facial hairs, the papillae of which are well supplied with 
nerves, termed vibrisscBf may be mentioned. 

In most, if not all Fishes, the integument of the body 
and of the head contains a series of sacs, or canals, usually 
disposed symmetrically on each side of the middle line, and 
filled with a clear gelatinous substance. The walls of the 
sacs, or canals, are abundantly supplied with nei-ves, and 
the terminations of the latter enter rounded papillae, which 
project into the gelatinous contents. These sensory organs 
are known as the " organs of the lateral line" or " mucous 
canals ;" and they were formerly supposed to be the secre- 
tory glands of the slimy matter which coats the bodies of 
fishes, and which is really modified epidermis. 

The Alimenta/ry Canal. — This part of vertebrate organi- 
zation always exhibits a differentiation into mouth, pharynx, 
oesophagus, stomach, and intestine ; and the last has always 
a median, or nearly median, aperture on the ventral surface 
of the body. It may open by itseK ; or into a cloaca, or 
chamber common to it, the urinary, and the genital organs. 

The intestine is generally distinguishable into smaU and 
large ; and, at the junction of the two, one or two cceca are 
frequently developed from the former. 



THE 1IVE2 AND THE TEETH. 87 

The stomach, and inteatijie are invested by a peritoneal 
mbrajie. And coimected, bj irtesogastrie and mexeiilerictoldB 
that membrime, with the median dureal w>iil of the abdo- 
imity. Glands appertaining to the lymphatic system 
quently abound in the meHentetii! folda, and a Jiighly 
Kulaf gland of this aystem, the spleen, is alnuja (except 
An^hiacus, Mymne, and the Iieptocephalidi:^) developed 
bloBe proximity to the stomaeh. K pancreatic gland very 
teraUy pours its Becretion into the anterior end of the 
eatjne. Balivary glanda very commonly open into the 
■ and, in the higher Vertebrata, anal glands are not 
Eienally developed in connection with the termination of 
S rectam. 

3 atniotnrea connected with the alimentary canal of 
tebrate animals, which are most characteristic and pecn- 
e the liver and the teeth. 



e JAver. — In invertebrate animala this organ is always 
tmately resolvable into cacal tubes, the ends of the 
atio ducts, which are lined with an epithelium, and not 
Culated ; and it has no receptacle for the bile. In most 
fiebrata the ends of the hepatic ducts have not been 
actorUy traced, nor is it certain that the immense pro- 
^onal mass of hepatic corpuscles is contained in tubes 
la with them; if such be the case, the tubes must be 
oalated. The ducts of the vertebrate liver very f reciuently 
r the bile, directly or indirectly, into a receptacle, the gall- 

. .JmjiAioxiJs stands alone among vertebrated. 
luTing a ciEcal diverticulum of the intestine for a Uver. 

Teeth. — Teeth, in MoUubixi and Amvulosa, are always 1 

" cutieular, or epithelial Btraotures. In Verte- 
tme teeth are invariably " enderonio," or developed, I 
tbe epithelium of the mucous membrane of the I 
canal, but from a layer between this and the I 
deep substance of the enderon, which a 

the integument. The homy " teeth" of the 
and of Omiihorh^ickm, appear to he ecderouio I 



I 

I 




S8 THE ANATOMY OF VERTEBKATED ANIMALS. 

atnictures, homologoits with the "balerni" of the Cetatna, 
with the palatal plates of the Sirenia, or the beaks of Bird* 
and Beptilei, and not with true teeth. 

The dense calcified tissue called define, characterised 
by the olose-aet parallel tubnli which radiate thi-ough il, 
branching as they go, conatitntea the chief mass of true 
teeth; bnt the dentine may be coated with ordinary bony 
tissue, which then receires the name of ceiaenta/m, and its 
crown may be capped with imperforate, prismaticaUy fibrou& 
enamel. 

The teeth ai'e moulded upon papilliB of the mucous man- 
brane, which may be exposed, but are more iiBUully suiik in 
a, fold or pit, the roof of which may close in so as to form A 
deiUai Aim. And there may he one set of teeth, or Bevetal ; 
the sacs of the aew teeth, in the latter case, being developed 
either as diverticula of the old ones, or independently of 

In the majority of the Mafovmaiia the teeth are limited ii 
number, as well aa definite in their forms and their mode of 
snoeeBaion. There are two seta of teeth, forming a first, i/eri- 
dMMW, or mtiA (fcnii/ion, and a second, or permanent deniituM. 
The decidnons dentition, when most completely developed] 
conaiata of iimiaor, canine, and molar teeth. The incison ai 
diatingnialied from the rest by the lodgment of the upper M 
in the pr pnia.-dll ig, und the coiTcspondence of the lower set 
with the upper. Their number and form vary. The dis- 
tinction between canines and molars is one of form and 
position in regard to the remaining teeth ; the most anterica' 
of the teeth behind the premaiillo-maxiUary suture, if it ic 
sharp and projecting, receiving the name of canine. Iben 
are never more than four canines. The other teeth are molara, 
and ordinarily do not exceed four upon each side, above and 
below. What is called a dental fonaala is a convenient 
combination of letters and figurea for making the nnmbM 
and disposition of the teeth obvioua. Thus, let di, de, t 
represent, respectively, the deciduous, or milk set of ineisors, 
canines, and molars. Then, by placing after each of these 
B^^.ged so as to show the number (f 



DEKTAL FORMULA. 89 

teeth of the kind symbolised, on each side of each jaw, we 
shall have the dental formula of a given animal. The 
dental formula of a child over two years of age is thus — 

di, — - dc. = — - dm. -li = 20 : which means that the 

child should have two incisors, one canine, and two molars 
on each side of each jaw. 

The neck of the sac of each deciduous tooth gives off a 
diverticulum, in which one of the permanent teeth is de- 
veloped; as it grows, it causes the absorption of the fang 
of the corresponding deciduous tooth, which thus becomes 
shed, and is replaced from below by the permanent tooth. 
The same letters, but without the prefix d, are used for the 
permanent incisors and canines ; but the permanent teeth, 
which replace the deciduous molars, are called premolars, 
and have the symbol jpm. Furthermore, three or, it may be, 
four permanent grinding teeth, on each side of each jaw, are 
developed altogether behind the milk molars, and thus come 
into place without replacing any other tooth from below. 
These are called molars, and have the symbol m. Thus the 
formula of the permanent dentition in Man is written : 

2-2 1—1 2*2 3*3 

**9^ ^' 1 — T ^^' ^^'^i = 32 ; there being two incisors, 

one canine, two premolars, and three molars on each side 
above and below. It is a rule of very general applica- 
tion among the Mammialia, that the most anterior molar 
comes into place and use before the deciduous molars are 
shed. Hence, when the hindermost premolar, which imme- 
diately precedes the first molar, comes into use by the 
shedding of the last milk molar, the crown of the first molar 
is already a little ground down ; and this excess of wear of 
the first molar over the adjacent premolar long remains 
obvious. The fact that, in the permanent dentition, the last 
premolar is less worn than the first molar which imme- 
diately follows it, is often a valuable aid in distinguishing 
the premolar from the molar series. 

No vertebrate animal has teeth in any part of the ali- 
mentary canal save the mouth and pharynx — except a 



OF VEBTEBBATED ASIMAL3. 

Bnake (.Bach toiion), which L3.B a aeriea of whi),t must be termed 
teeth, formed hy the projection of the inferior spinous pro- 
ceHBee of numerouB anterior Tertebi-se into the oesophagus. 
And, in the highest Yertebrata, teeth are confined to the 
premaxilliE, masillaj, and oittudible. 

The Circulatory Orgam. — The heart of the vertebrate em- 
bryo is at first u simple tube, the anterior end of whidi 
passes into a cardiac aortic trunk, while the posterior wi 
is continuous with the great veins which bring back blood 
from the nmbilical vesicle— the omphaiomeaeraie vei-ns. 

The cardiac aorta immediately divides into two brancheai 
eack of which ascends, in the first visceral arch, in the 
foiin 6f a forwardly convex aorlie arch, to the nzider nda 
of the mdimentary spinal colTinin, and then runs, paralld 
with its fellow, to the hinder part of the body, as a pri- 
mUive eabv^tebral aorta. The two primitive aartt^ verj 
soon coalesce throughout the greater part of their length 
into one trunk, the definitive suhvertebral aorUi; but the 
aortic arches, separated by tke alimentary tract, remaJA 
distinct. Additional arterial trunks, to tbe number of four 
in the higher Yertebrata, and more in the lower, are succes- 
sively developed, behind the first, in the other visoeral arohes. 
and further connect the caj'diac and aubvertebral aortee. 

In the permanently brancliiate Yertebrata, the majority o! 
these aortic arches persist, giving off vessels to the br^icbial 
tafts, and beeoming converted into afferent 
trunks, which carry the blood to and take it from these 
tufts. (Fig. 35, A, B, C, D, B.) 

In tbe higher Amphibia, which, though branchiate in the 
young state, become entirely air-breathers in the adnlt con- 
dition, such as the Batrachia (Fig. 25, P> and CxciUa, ibt 
permeable aortic orchcB are reduced to two (the middle pair 
of tbe three which supply tbe external gUls, and the foortk 
pair of embryonic aortic arches) by tbe obliteration o£ tht' 
cavities of the dorsal ends of the others. Of the 
arches, the remains of thi' fifth and sixth become the 
which give off the pulmuuui'y arteries, and, in tbe JafracM^ 



MODIFICATIONS OF THE AOBTIC ABCHES. 



91 



Fig. 25. 
,. Hfn. Ey. Br^ Br.^ BrJ Br.^ Br.^ Bk^ Bn^ 



A. 



O](0]@[0][0](0J@[0 



p^i 



ZAC. 



I nmivvvi-viivmix: 




lU IV" V VT VTT. Vlff K 



'ig. 25.— A diagram intended to show the manner in which the aortic 
arches become modified in the series of the Vertebrata. 

L. A hypothetically perfect series of aortic arches, corresponding with 
the nine postoral visceral arches, of which evidence is to be found in 
Bome Sharks and MarsipdbranchiL A.C. Cardiac aorta ; A.D. Dorsal 






!J2 THE ANATOSir OP VERTEBRATBD AtflMAXS. 

or subverlcbral aorta, i.— ii. the aortic arches, coirespondii 
Mn., the mandibular ; /7j-., the hjoidean, and Sr.i " - -'- 
brancLial visceral arches, i, ii. in. iv, v. vt. vii.. tl 
clefla. The first vlsc^ml clefl ia left unnumbered, 
added lo the number of each branchial deft to gii 
the series of visceral clefts. 
B, Uynothedcsl diagram of the aortic archeain the Shark IfrpU 



ss 

visceral clett bb ihi 

C. Jjrpidotirm. — The first arch has disappeared as such, and the Qol 
visceral cleft is obllteraied. Internal branch^ie ere developed in 
connection with the second, fifth, sixth, aud seveuth aortic ar'- 
external branchis in connection with the fonrth, fifth, and 
PA. the pulmonary artery. The posterior two visceral cleft» an 

D. A Telcusl'ean Fish— The first aortic arch and fint visceral uldl 
are obliterated, as before. The second aortic arch bears the paeaio- 
brancliia (_Fs.B.), whence issues the ophthalmic artery, it) terminitt 
in the choroid ghind (CT.) The nest four arches bear gilla. Tbt 
seventh and eighth arches have been nbaerved in the embrjro, bot 
not Cheninth.andthcincluderlcletts are absent in the adult. 

E. The Axolotl (Sirerfon}, a perennibranchlate amphibian. Thedilrd, 
jbnrth, fifth , and sixth aortic arches, and the anterior Tour braneliU 
clefts, persist. The first visceral olefi is obliterated. 

F. The Fru».— The three anterior aortic arches are obliterated in tbl 
nduh. The place of the third, which is coimected with the antetinr 
external ^ill in the Tadpole, is occupied b; the common carotid ind 
the rt(e mirabik (carotid yland, t7u.C,) which lerminstes it. Tht 
fourth pair of aorlio arches persist. 'I'ho fifth and siith p^ loM 
their cunnections with the subvertebral aortic tmnlt, and becomf 
the roots of the cutaneoua and pulmonary arteries. The fini 
visceral cleft hecomca the tympanum, hut all the others are obllt*' 
rated in the adolt. 

eutaneous branches. The anterior, or third, primitive aortic 
arch becomes the common carotid ti-nnk, and ends in the 
carotid gland, whence the internal and eirtemal carotidi 
arise. In those Vertebrata which never poaseee gills, thA 
arches become reduced either to two pair, as in aome Laear- 
iilia ; or to one pair, as in other Meptilia ; or to a sin^ 
arch, as in Aues and Mamtaiilia. The aortic archee thw 
retained are, in the Lizards in question, the third and. tllA 
fourth pairs in order from before backwards ; but ths 
fourth pair only, in other Reptiles ; in Birds, the right : 
onlj of the fourth pair ; and in Mammals, the left arch oatf 
of the fourth pair. The fifth pair of arches give t ~ ' 
pulmonarj arteries, the so-called " duetiia arterioett»" 



: DETELOPMBST OF THF 



SYSTEM. ^3 I 

Wing the remaiiiB of the primitive comiectioii of these I 

a with the fourth paii' and the eulivert«hral aorta. 1 

B doreal enda of the first, second, and third arches become 1 
(ilfliterated ; but theii- cardiac ends, and the brancheg which 
ihey give off, become the arteriee of the head and upper 



The embryonic iiorta gives oiT 07iyiAaIorocsBroic branches i 
(Pig. 26, o) to the umbilical vesiclei and ends, at first, in the i 
hypogagtric arteries (which are distributed to the allantois J 
in the abranchiate Vertebraid), and a median caudal ( 
tinnation. The blood from the umbilical vesicle is brought 
back, as before mentioned, by the umphalomeseraic v< 
(Fig. 26, o'), which unite in a dilatation close to the head ; the 
dila.tatioa {siwit vetiowits) receives, on each side, a short J 
transverse venous trunk, the itefu* Oumieri (Pig. 26, HC), 
which is itself formed, upon each side, by the junction of I 
the anterior and posterior cardinal vm,ni, which run back- 
wards and forwards, parallel with the spine, and bring back ] 
the blood of the head and of the trunk. 

The blood of the allantoia ia returned by the i/TuMlical 1 
vein, or vein* (Pig. 26, u'), which are formed in the anterior 
wall of the abdomen, and open into the venoiia sinus before i 
mentioneiL The blood of the posterior esti-emities and I 
li'ineys is, after a while, brought to the same point by a 
■I ■■".■ill median vein, the wenffl oava inferior (Fig. 26, cu.). 
The development of the liver effects the first great change 
•d ibe arrangements now described. It, aa it were, in- 
i.rrupta the coui-ae of the omphalomeseraic vein, which is 
□rit iinly the vein of the lunbilical sac but also that of the 
iiitcstine, and converts it into a meahwork of cimalB, which 
I'ommtmicBte, on one side, with the cardiac part of the vein, 
dad, on the other side, with its inteatiual part. The latter 
K thus converted into the vena porttE (Pig. 26, iJp.), dis- 
tribating the blood of the stomach and intestines to the 
, I.T; while the former becomes the Aepafe vein (ch). carry 
■n; hepatic blood to the inferior cava, and thence to the 



94 THE AHATOKY OF VEBTEBBATED ANIHAXS. 

The Tuubilical vein further givea a, branch to the liver; 

while, on the other hand, it communicateB directly with the 

venous sinus {now almost merged in the vena cava vaferiar) 

by a tronk called dMciag venosat (Fig. 26, Du.). 

Fig. 26. 




Fie, 26.— Diaei'siii of ^^ arrangement of the principal veseela in s 
human fiEtUB. H. the heart; T.A. the aortic trunk or oardlao 
oorla ; '. the common carotid ; c' the eilcrnal carotid ; c" the Internal 
oorotid i I. subclavian ; o. vertebral artery ; 1, 2, 3, 4, 5, the oorUc 
Brohea— the perfliBlent left aortic arch is hidden ; A.' subvertehral 
aorta; D.ompiiBlomeseiafcarter^.goin; to the umbilical vesicle 0, with 
Ita vitelline duct jv. ; 0, omphalomeseraic vein; rp, the venaportEe; 
L. the liver ; «u, the hypogastric or umbilical arteries, with their 
placental ramlticatioaa, u'^u" ; u' the umbilical vein; Z>e, the ductus 
venoaus ; nh, the hepatic vein ; to, the vena cava inferior ; cii, the 
iliac veina ; oz, a vena aiygoa; cc', a vena cardinolis posterior; 
DC. a dudns Cuvieri! the anterior cardinal vein is seen com- 
mencing in the head and running down to the ductusCuvieri on the 
under side of the numbers 1, 2, ^ 4, 5 ; F, the tunga. 

When the umbilical reside and aUantoia ceaae to have any 
farther import, as at birth, or beiore, the om-gtaioTi 



THE MODIFICATIONS 



i VAfiCDLAK STBTEM. 



arterieB have become intestinal arteries, and the omphali 
meseraic vein, the vena porta. The hypogastric art<?rieB a 
obliterated, except so mnch of them na is converted into th^fl 
1 iliac aiteries. The umbilieal vein, or veins, abK>l 
ir are represented by mere hgamentH. 

Of the three veioBwhichopen into the venoae sac — viz.,fchfl^ 
inferior cava, and the right and left ductag Otivieri. — all may 
persist, the latter receiving the title of right and left tntpetuor 
cavtB. Or, as vety often happens in the higher Vertebrata, 
the left dtwrfiM Cwiieri becomes more or lesB obliterated ; the 
(eina which properly open into it acquiring a connection. J 
with the right duciu*. which then remains as the Bolal^ 
gvperior cava. The posterior cardinal veins give off a 
tomosing branches, which are converted into the t 
azygog ; the anterior cardinal reina become metamarphosed I 
'a and vents iiuwiitinaite. 

and the cardinal veins persist I 
thronghout life; but the anterior cardinal veins, whiebj 
bring back the blood from the head and from the amteriof J 
eitremities, are called vencBJagulures, 

The eandal veins are either directly continued into tJififl 
cardinal veins, as in Marsytobranchii and Elasiiiobranckii, oi 
branch out into the kidneys, as in many Teleoetm. In either! 
case the effei'ent renal veins open into the cardinal v 

Tbe portal veins, conveying the blood of the chylopoietic 
viscera, and sometimes that of other organs and of the abdo- 
minal waJla.may be one ormany. In AwphioxTisajiAMyxi'ae 
the vein is rhythmically contractile, and forms a portal 

In most Amphibia and BepUlia the dwis venoeus persiatB. I 
.ind LB rbythmicaily contractile, valves being placed at its I 
upoaing into tbe right auricle. 

Tbs anterior cardinal veins are represented by jugnlaC 1 
tttus. tb£ posterior cardinal by vertebrtU veins; these, and j 
veins of the anterior extremities, when they i 
snt, pour their blood into the daekie Cwien, which aro I 
tr termed anterior vencB eaucB, 

: tj^erior takes its origin chiefly by the 



9f; THE ANATOftTY OF VBETEBEATED 

coaleBcence of the efferent vejna of the Iciineja and n 
productive organs, and doea not always receive the wbole 
of tlie hepatic veina — more or fewer of the latter opening 
independently into the ainus venoeas. 

The blood whii;h leaves the kidneys by its efferent vi 
ia supplied, not only by the renal arteriea, but by the t 
of the caudal region, and of the hinder extremitiea, whioh 
branch out like a vena porbs in the eitbetance of the 
kidneya. This renal portal system ia leaa developed i 
Sepfilia than in Ainphibia. Ail the blood of the posterior 
extremitiea and caudal region does not traverse the kidntT*. 
however, more or leas of it being led away by great brancW 
of the iliac veina, which run along the anterior wall of the 
abdominal cavity, either aa two tninta, or nnited into oi 
These venm ahdcminales anteriores are eventuaJIy distri- 
buted to the liver, along with the branchea of the proper 
vena portis. 

In Birds, the «na» •eewmia is not distinct from the right 
auricle, and there are two anterior venm cavm. The o 
cava mfeiHor arises, as in Mam-maJa. by the union of tin 
two common iliac veina. It receives both the right sai 
the left hepatic veins, and, in addition, the anterior abdfr 
minal vein no longer entera the portal ayatem, but pssaM 
up the anterior wall of the abdomen and through tfi( 
hepatic fissure to join the inferior cava 

The caudal and pelvic veina unite into three prindpl) 
trunks, of which one is median and two are lateraL Tin 
median entera into the portal ayatem. The lateral bninchM 
paaa along and through the kidney, receiving v 
it, but giving none to it ; and eventually, after receiving tbt 
ischiatic veins, nnite with the crural veina to form the ooiB> 
mon iliaca. Thus there ia no renal poi-tal ayatem in bird*, 

In Mum/malui, the siwia venomu ia not diatinct from tlie 
right anricle. The anterior cavm are frequently reduced t 
one. the right. The veaa cava inferior commeneea in tb 
caudal region, and receivea all the blood of the postencT 
moiety of the body, except so much aa is carried a,\raj by 
the azjgous veina. The anterior abdominal veins are repra- 



THE MODIFICATIONS OF THE HEABT. 97 

sented only during foetal life, by tlie umbilical vein or 
veins. The efferent- veins of the kidneys open directly 
into the trunk of the inferior vena cava, and the portal 
vein is composed exclusively of radicles proceeding from 
the chylopoietic viscera. 

Many of the veins of Amphioxm, the portal vein of 
Myxine, dilatations of the caudal vein in the Eel, the vena' 
cavee and the iliac and axillary veins of many Amphibia^ 
the veins of the wing of Bats, possess a rhythmical con- 
tractility, which, in combination with the disposition of theii* 
mlves, assists the circulation of the blood. 

In Vertebrata of all classes, and in very diverse parts of 
the body, both veins and arteries occasionally break up into 
numerous branches of nearly equal size, which may or may 
not unite again into larger trunks. These are called retia 
mirabUia. 

Modifications of the Heart. — Great changes go on in 
the structure of the heart, pari passu with the modifica- 
tions of the rest of the circulatory system, in the develop- 
ment of the highest Vertebrata. The primitively simple tube 
becomes bent upon itself, and divided from before back- 
wards into an aortic, or ventHcular, and a venous, or a\iri- 
cuHar, portion. A median septum then grows inward, divid- 
ing the auricular and ventricular chambers into two, so that 
a right auricle and right ventricle become separated from 
a left auricle and left ventricle. A similar longitudinal 
division is effected in the cardiac aorta. The septa ai*e so 
disposed in the auriculo-ventricular chamber that the right 
amide communicates with the venous sac and the tmnks 
of the visceral and body veins, while only the veins from 
the lungs enter into the left auricle. And the cardiac- 
aorta is BO divided that the left ventricle communicates 
with the chief aortic trunk, the right with the pulmonary 
artery. Valves are developed at the auriculo-ventricular 
apertures and at the origins of the aortic and pulmonary 

: tnmks, and thus the course of the circulation is determined. 

\ The septum between the auricles remains incomplete for a 

\ H 

1 

I. 
i 



98 THE ANATOMY OP VERTEBRATED ANIMALS. 

much longer period tlian that between the ventricles — and 
the aperture by which the auricles communicate is called 
the foramen ovale. 

In the adult state of Aves and Mammalia^ the foramen 
ovale is closed ; there is no direct communication between 
the arterial and venous cavities or trunks; there is only one 
aortic arch ; and the pulmonary artery alone arises from the 
right ventricle. In the Crocodilia, the auricles and ven- 
tricles of opposite sides are completely separate ; but there 
are two aortic arches, and one of these, the left, arises from 
the right ventricle along with the pulmonary artery. In all 
Beptiliat except Crocodiles, there is but one ventricular 
cavity, though it may be divided more or less distinctly into 
a camim venosum and a cavum arteriosum. The auricles are 
completely separated (except in some Chelonia), and the 
blood of the left auricle flows directly into the cavwni arteruh 
sum, while that of the right passes immediately into the 
cdvum venosum. The aortic arches and tiie pulmonary artery 
all arise from the cavwm venosum (or a special subdivision 
of that cavity called the cavum pulmonale) ; the ostium of the 
pulmonary arteiy being fartiiest from, and that of the right 
aortic arch nearest to, the cavum artemosum. 

Jn all Am^phihia, the spongy interior of the ventricle is 
undivided, and the heart is trilocular, though the auricular 
septum is sometimes small and incomplete. In all Pisces, 
except Lepidosireny there is no auricular septum. In Am,- 
phioxus the heart remains in its primitive state of a simple, 
contractile, undivided tube. 

In the Ganoidei, the Elasm^ohranchii, and the Amphibia^ 
the walls of the enlarged commencement of the cardiac 
aorta, called the hulhus aortce, contain striped muscular 
fibre, and are rhythmically contractile. 

The Ganoidei and Ekismohranchii possess, not merely the 
ordinary semilunar valves, at the junction between the 
ventricle and the cardiac aorta, but a variable number of 
additional valves, set, in transverse rows, upon the inner 
wall of the aortic bxdb. 

The change of position which the heart and the great 



THE BLOOD-COEPUSCLES. 99 

'easels of the liighest Vertehrata undergo during embryonic 
if e is exceedingly remarkable, and is repeated as we ascend 
a tlie series of adult vertebrates. 

At first, the heart of a mammal lies under the middle of th(^ 

lead, immediately behind the first visceral arches, in which 

he first pair of aortic arches ascend. As the other pairs of 

Lortic arches are developed the heart moves backward ; but 

lie fourth pair of aortic arches, by the modification of one 

>f which the persistent aorta is formed, lies, at first, no 

farther back than the occipital region of the skull, to which, 

3is we have seen above, the fourth pair of visceral arches 

belongs. As the two pairs of comua of the hyoid belong 

to the second and the third visceral arches, the larynx is 

probably developed within the region of the fourth and 

fifth visceral arches ; hence, the branches of the pneumo- 

gastric, with which it is supplied, must, originally, pass 

directly to their destination. But, as development pro- 

ceedSy the aortic arches and the heart become altogether 

detached from the visceral arches and move back, until, at 

length, they are lodged deep in the thorax. Hence the 

elongation of the carotid arteries ; hence also, as the liiiynx 

remains relatively stationary, the singular course, in the 

adult, of that branch of the pneumogastric, the recurrent 

laryngeal, which primitively passed to the laryngeal region 

behind the fourth aortic arch, and consequently becomes 

drawn out into a long loop — the middle of it being, as it 

were, prilled back, by the retrogression of the aortic ai'ch 

into the thorax. 

The Blood Corjpuscles, — Corpuscles are contained in the 
blood of all Vertehrata, In Amphioxiis they are all of one 
kind, colourless and nucleated. The genus Leptocephalus, 
among the Teleostei, is said to possess the same pecu- 
liarity ; but in all other known Vertehrata, the blood con- 
tains corpuscles of two kinds. 

In Ichthyopsida and Sauropsida, both kinds are nu- 
cleated; but one set are colourless, and exhibit amajboid 
movements, while the others are red, and do not display 



IW THE ANATOMY OF VEETEBEATED ANIMALS. 

eonti-actilitj. Except in the Marsipobranckii, wliicli hare 
i-oimd blood-corpuBclea, the red corpuscles are oval. They 
attain a larger size in the perennihraochiate Amphibia 
than in any other Tertebrates. 

In MaviTnalia, tho hlood-oorpnacles are alao of two 
coloitrleBB and red, the colourleBs poasesHiiig, and the red 
being devoid of. nuclei. It ia but very rarely that a 
cleated corpuacle, with a red colour enpeciajly developed 
about the nucleus, ie seen in Mammalian blood; but saA 
cases do occur ; and, from thia and other circiunatances, it 
is probable that the Mammalian red corpuscle is a free- 
coloured nueleuB. 

The colourless coi-pusclea of Mammalia are spheioidtkli 
and exhibit anuubuid movementa; the red corpuscles art 
flattened, usually circular, but sometimes oval (Camelidai 
dieos, devoid of contractility. 

The I/yT>iphatic System. — This eyatem of vessels consiati^ 
chiefly, of one or two principal trunks, the thoraeie (iud, of 
diicU, which underlie the vertebral column, and commiillfc' 
oate. anteriorly, with the saperior vena caTte, or with Urt 
veins which open into them. 

From these trunks, bi-anches are given off, wliich tuhoSJ 
through ull parts of the body, except the bulb of the eyti 
the cajrtilagea, and the bones. In the higher VerldnvtOi 
the larger branchea are like small vmns, provided wiA 
definite coats, and with valves opening towards the largsf 
trunks, wbile their terminal ramiflcationa form a capillsQ 
network ; but, in the lower Vertebrates, the lymphalic ' 
channels aaaume the form of large and irregular siniueii 
which not unfrequently completely enrroimd the great 
vessels of the blood syatem. 

The lymphatics open into other parts of the venooi 
system besides the affluents of the supenor cavs. In Fisfaci 
there are, usually, two caudal lyraphiitic suiuaea which c^w^i 
into tlie commeacemeut of the caudal vein. In th« Vre^ 
four such sinnaes communicate with the 
coccygeal, and two in the scapular, region. The walla. 




THE BESPIBATOBY ORGANS. 101 

these smuses are muscular, and contract rhythmically, so 
that they receive the name of Lymphatic hearts. The pos- 
terior pair of these hearts, or non-pulsating sinuses cor- 
responding with them, are met with in Beptilia and Aves. 

Accumulations of indifferent tissue in the walls of some 
of the lymphatic sinuses are to be met with in Fishes ; 
but it is only in the CrocodUia, among Reptilia, that an 
accumulation of such tissue, traversed by lymphatic canals 
and bloodvessels, is apparent, as a Ijynvphatic glands in the 
mesentery. Birds possess a few glands in the cer\'ical 
region ; and, in MammaMa, they are found, not only in the 
mesentery, but in many parts of the body. 

The Spleen is substantially a lymphatic gland. The 
Thymus — a glandular mass with an internal cavity, but 
devoid of any duct — ^which is found in all Vertehrata except 
AmphioxuSf appears to belong to the same category. It is 
developed in the neighbourhood of the primitive aortic 
arches, and is double in most of the lower Vertehratay but 
single in Mammalia, 

The nature of two other " ductless glands," the Thyroid 
gland and the Suprarenal capsules, which occur very widely 
among the Vertehrata, is by no means well understood. 

The thyroid gland is a single or multiple organ, formed 
of closed follicles, and is situated near the root of the aoi'ta, 
or the great lingual, or cervical, vessels which issue from it. 

The suprarenal capsules are follicular organs, often 
abundantly supplied with nerves, which appear to occur in 
Fishes, and are very constant in the higher Vertehrata, at 
the anterior ends of the true kidneys. 

[' The I/ymph Corpuscles, which float in the plasma of the 
'- lymphatic fluid, always resemble the colourless coi-puscles 
'< of the blood. 

■ 

The Respiratory Organs. — Yertebrated animals may possess 
either branchiae for breathing the air contained in water, or 
hngs for atmospheric respiration ; or they may possess both 
kinds of respiratory organs in combination. 

/ 



Ul2 THE ANATOMY OP VEETEBEATED AMIMALS. . 

Except in Amphioxtig, the branekUB are always lamellar, 
or iilamentous, appendages of more or fewer of the visceral 
iu'chea ; being aometimes developed only on the proper bran- 
chial ai'clieB, sometimea extending to the hyoidean arch, or 
( as would appear to be the cose with the Bpiraciilaj- branduB 
of some fishes) eren to the mandibular iircb. The brtmcUv 
are always enpplied with blood by the divisiouB of the 
oardiac aorta; and the different trunks which carry the 
aiirated blood away, unite to form the subvertebral aorta, 
ao that all vertebrated animals with exclnsively bralicbial 
i-espiratioa have the heart filled with venous blood. 

In the early life o( many branohiated Verlebrata, tlH 
branchite projeut freely from the Tieceral archee to whick 
they are attached, on the exterior of the body; and in Bomo 
A-ayphihia, such as the Axolotl {Siredon), they retain their 
form of sel^rnal phimelike appendages of the necV throngh- 
out life. But in the adult life of moat Fiahea, and in the 
moiv advanced condition of the Tadpoles of the higher 
Ampkibirt, the biuncbife are internal, being compoeed <i 
shorter procesaes, or ridges, which do not project beTonJ 
the enter edges of the branchial clefts ; and, genera]ly> 
Ijecome covered by an. operculum developed from the second 
visceral arch. 

The lungs of vei-tebnited a.nimn.lw are eaes, capable of 
being filled with air, and developed from the ventral wall ct 
the phuiynx, with which they remain connected by a shorter 
or longer tube, the trachea, the division of thia for enob 
lung being a bronehua. Venous blood is conveyed to than 
directly from the heart by the pulmonary arteriea, nnd' 
some* or all of the blood which they receive goes btu^.ao 
less dii-ectly, to the eame oi^n by the pulmonary veins. 

The vascular distribution thus described conatitates n 
essential part of the deSnitiou of a lung, as many ftdiat 
posaess hollow sacs fiUed with sii'j and these saca are dS" 
veloped, occasionally, from the ventral, though more ooill- 
nionly from the dorsal, wall of the pharynx, (esophaguo, « 

* GeneTally all, liut in soma of tlic blood supplied to the tBt|Rl 
Anqihibiu, auet bb I'rotcut, part enlera the genenl ciceiilar' " " ^ 



THE OBGANS OP VOICE. 103 

stomach. But sucli air-sacs — even when they remain per- 
manently connected with the exterior by an open passage or 
pneumatic duct — are air-bladders, and not lungs, because they 
receive their blood from the adjacent arteries of the body, 
and not direct from the heart, while their efferent vessels 
are connected only with the veins of the general circulation. 
The wall of each pulmonic air-sac is at first quite simple, 
but it soon becomes cellular by the sacculation of its 
parietes. In the lower pulmonated Vertehrata, the sacculation 
is more marked neai* the entrance of the bronchus ; and when 
the lung-sac is long, as in many Amphibia and in Snakes, 
the walls of the posterior end may retain the smooth con- 
dition of the embryonic limg. In Clielonia and Crocodilia, 
the lung is completely cellular throughout, but the bronchi 
do not give off branches in the lungs. In Birds, branches 
are given off at right angles ; and, from these, secondaiy 
branches, which lie parallel with one another, and eventually 
anastomose. In Mamvmalia, the bronchi divide dichoto- 
mously into finer and finer bronchial tubes, which end in 
sacculated air-cells. 

BUnd air-sacs are given off from tlje surfaces of the huigs 
in the Chamadeonidoe, and the principal bronchial tubes 
terminate in large air-sacs in Aves, 

The Larynx and tlie Syrinx. — The trachea is commonly 
kept open by complete, or incomplete, rings of cai-tilage, 
and the uppermost of these undergo special modifications, 
which convert them into a Larynx, an organ which, under 
certain circumstances, becomes an instrument of voice. 

When completely developed, the larynx presents a ring- 
like cartilage called cricoid, which lies at the summit of the 
trachea. With the anterior and dorsal edge of this, two 
arytenoid cartilages are moveably articulated, and a thyroid 
cartilage of a V-shape, open behind, is articulated uiove- 
ably with its sides. Folds of the mucous membrane, con- 
taining elastic tissue, termed the vocal cords, stretch from the 
arytenoid cartilages to the re-entering angle of the thyi-oid 
cartilage, and between them lies a slit-like passage, the 
glottis. This is covered by a cai-tilage, the epighttisy attached 



Vli THE ANATOMY r 

to the re-enteviog angle of tlie thjToid, luid to the base of 
the tongue. Folds of mticotis membrane, extending from the 
epiglottis to the arytenoid cartilagei, are the orygrtjiottw 
ligaments. TheinnerBnvfacaaof these endbelowiutlie/iiiM 
vocal cords, between which and the traeckordce i'oco(e», liere- 
cesaea of the mucous membrane, the vfTttriclai of the hujnx. 

The chief accessory cartilages are the cartilages of San- 
torini, attached to the summits of the aJTtenoid cartilages, 
and the cartUagea of WrUberg, which lie within the ary 
epiglottic ligaments. 

Birds possess a larynx in the ordinaiy position ; bnt it is 
another appai-atits, the lower Uirynx or gyriiur, develppei 
either at the end of the tnwhea, or at the commencetncnt 
of each bronchus, which is their great vocal organ. 

Tim Mecha-niam oj Bespiration. — The mechanism by which 
the aerating medium is renewed in these different reE^iiar 
tory organs is very various. Among branchiated Vertebrato, 
Aitiphioxns stands alone in having ciliated branchial organs. 
whichformanetworkvery similar to the perfoi-ated phaiyo- 
geal wall of the Asciflians, Most Fishes breathe by taldng 
aerated water in at the mouth, and then shutting the oral 
aperture, and forcing the water through the branchial cleftft 
when it flows over the branchial filaments. 

Puhtionated Vertebrain which have the thoracic skeletcm 
incomplete (as the Amphibia), breathe by distending thsir 
pharyngeal cavity with air ; and then, the mouth and nostnla 
being shut, pumping it, hytheelevationof the hyoideannp- 
paratas and floor of the pharyns, into the lungs. A Frc^ 
therefore, cannot breathe properly if its mouth is kept wiit 

In must BeptUio, and in all Avea and Sfammalia, the 
sternum and ribs are capable of moving in such a way, m 
ultimately to increase and diminish the capacity of 1^ 
thoracico- abdominal cavity, and thereby to give rise to m- 
inspiratory and expii'atory flow of air. 

In the Seplilia, the elastic lungs dilate with the inspii** 
tory, and contract with the expimtory, act ; but in Avtt, 
the air rushes through the principal bi-onchiul passages 



THE BENAL ORGANS. 105 

he fixed and little distensible lungs, into the Tery dilatable 
nd compressible air-sacs. From these the act of expira- 
ion expels it back through the principal bronchial pas- 
ages to the ti*achea, and so out of the body. 

Both in JReptilia (e. g. Chelonia) and in Aves, muscular 
ibres pass from the ribs to the surface of the lungs beneath 
;he pleuroperitoneal membrane, and this rudimentary dia- 
phragm acquires a very considerable development in the 
RcttUce, or struthious birds. So far as the contraction of 
i^ese fibres tends to remove the ventral from the dorsal 
oralis of the lungs, they must assist inspiration. But this 
diaphragmatic inspiration remains far weaker than the 
stemo-costal inspiration. 

Finally, in the Mcmimalia, there are two equally important 
respiratory pumps, the one stemo-costal, the other dia- 
phragmatic. The diaphragnit though it makes its appear- 
ance in Say/ropsida, only becomes a complete partition 
between the thorax and the abdomen in mammals ; ^nd 
as its form is such, that, in a state of rest, it is concave 
towards the abdominal cavity, and convex towards the 
thorax, the result of its contraction, and consequent flat- 
tening, necessarily is to increase the capacity of the thorax, 
and thus pump the air into the elastic lungs, which occupy 
a large part of the thoracic cavity. When the diaphragm 
ceases to contract, the elasticity of the lungs is sufficient to 
erpel the air taken in. 

Thus, mammals have twO kinds of respiratory mechanism, 
either of which is efficient by itself, and may be carried on 
independently of the other. 

The Benal Organs. — The higher Vertehrata are all provided 
with two sets of renal organs, the one existing only during 
the early f cetal state, the other persisting throughout life. 

The former are the Wolffian bodies, the latter the true 
Kidneys. 

The Wolffian bodies make their appearance very early, on 
each side of the ventral aspect of the spinal region of the 
embryo, as small transversely-disposed tubuli, opening into 



106 THE ANATOMY Ol' VEBTEBKATED ANIMALS. 

a duct wbiith lies upon theiv outer aide, and enters, poste- 
riorly, into the baae of the allantoie, and tLence int« the 
primitiye clonca, with which that Btmcturo ia connected. 
The Wolffian duct is one of the first-formed Htmctures in 
the embryo, and precedes the tnbuli. 

The Kidneys appear behind the Wolffian bocHes, and, appa- 
rently, independently of them ; their dncta. the vireleri, W* 
also distinct, but likewise terminate in the pelvic part of Qtt 
aUantoix. Thus the urinary secretion pasaes into the aBni!- 
toie, and it ia that portion of tbia organ whieb lies witluB 
the abdomen, and becomea shut off from the rest by the 
constriction and obliteration of the cavity of an intciaD^ 
diate part, and its conyersion into the v,rachva, that gim 
rise to the wrinary bladder. The ultimate aeereting tahrU 
of both the Wolffian body and the kidney, are alike »■ 
markable for ending in dilatations which embrace ea^ 
Toluted capillaries — the ao-called walpighiau tufts. Neitlur 
Wolffian bodies nor kidneys have been observed in Amphi- 
oxws. It is doubtful whether true kidneys are deTet<Qied 
in lehihyopaida, or whether the so-called kidneys 
animals are not, rather, persistent Wolffian bodies. 

The Beproiiactive Orgam. — These, in vertebrated 
are primitively similar in both sexes, and ariae on t 
side of the Wolffian bodiea, and in front of the kidn^a, im. 
the abdominal cavity. In the female the organ become! M 
auariwrn. This, in some few fishes, sheds its ova as eo^M 
they are ripened into the peritoneal cavity, whence Uitg 
escape by abdominal pores, which place that cavity in dinai 
communication with the exterior. In many flelies, tikfe 
ovaries become tubular glands, provided with continoosl 
ducta, which open externally, above and behind the 
But, in all other Viaiei>rata, the ovaries are glands witJMSt 
eontinuouH ducts, and which discharge their ova from t 
the Qraafian foUiclea, sueceasively developed in theii" ( 
substance. Nevertheless, these ova do not fall into 
peritoneal cavity, but are conveyed away by a special a] 
ratua, consisting of the FaUu^ian Men, which i-esiilt 



THE EEPEODTTCTIVE OBGANS. 107 

the modification of certain embryonic strnctures called tlie 
Miillerian ducts. 

The Miilleriaji ducts are canals which make their appear- 
ance alongside the ducts of the Wolffian bodies, but, through- 
out their whole extent, remain distinct from them. Their 
pTOxinial ends lie close to the ovary, and become open and 
dilated to form the so-called ostia. Beyond these ostia they 
generally remain narrow for a space, but towards their 
hinder openings into the genito-urinary part of the cloaca, 
they commonly dilate again. In all animals but the didel- 
phons and monodelphous Mammalia, the Miillerian ducts 
undergo no further modification of any great morphological 
importance ; but, in the monodelphous Mammialia, they be- 
come united, at a short distance in front of their posterior 
ends; and then, the segments between the latter and the 
point of imion, or still farther forward, coalesce into one. 
By this process of confluence the Miillerian ducts are 
primarily converted into a single vagina with two uteri 
opening into it ; but in most of the Monodelphia, the two 
uteri also more or less completely coalesce, until both 
Miillerian ducts are represented by a single vagina, a 
single uterus, and two Fallopian tubes. The didelphous 
IfanuiuiZia have two vaginae which may, or may not, coalesce 
anteriorly for a short extent; but the two uteri remain 
perfectly distinct. So that what takes place in them is, pro- 
bably, a differentiation of each Miillerian duct into Fallo- 
pian tube, uterus, and vagina, with or without the union of 
the two latter, to the extent to which it is effected in the 
earher stages of development in Monodelphia, The Wolffian 
ducts of the female either persist as canals, the so-called 
i tanaU of Chertner, which open into the vagina, or dis- 
appear altogether. Remains of the Wolffian bodies consti- 
tute the parovaria, observable in certain female mammals. 



In the male vertebrate embryo, the testis, or essential 

reproductive organ, occupies the same position, in front of 

tiie Wolffian body, as the ovary; and, like the latter, is 

^ eompoeed of indifferent tissue. In Amfphioxvs and in the 



I 



108 THR ANATOMY OF VERTEBBATED AHIMAl 

MareipobranEkU, thin tisane appears to pass directly int* 

spermatozoa ; but, in most Vertebrnta, it acquires a saccolac 

Fig. 27. 




a the gE^nertl plan (tho middle fieure) "f iheie at 
the higgler Verltbrala. 

0/, the clowft; B, the ractom ; fl', the arlnory bladjer j ( 
ureter; £, (he kidney; Uh, theurethrn; G. the ^nilal glnnd. ova. 
testis; tK. the WDllfliin body: ITd, the Wolfflitiiducti JI/.theHuSt 

duflt i Pif. proilftte glaiid ; Qi, Cowpar's glnnd ; C>p,theoi " 

gioBum; CV, the corpus (Svernosuin. 

In the female, I', the vngina ; Ij't, the uterus; f>j, the Fill 
tube; C(. Caertnor'silueti P.r,tliepBrovsrium; J, the i- - ■" 
the nliCoHs. In The male. Cup, Cc, the penis ; Ut. Ibe 
Uaui ; 1 1, vesicuin geminallB ; I'J, Iha vag deferens, 

or tubular structure, and from the epithelium of the ai 
tubulii thep — 4^a are developed. At firat, the U 



MODIFICATIONS OF THE EEPBODUCTIVE ORGANS. 109 

as completely devoid of any excretory canal as the ovary ; 
but, in the higher vertebrates, this want is speedily supplied 
by the Wolf&an body, certain of the tubuli of which become 
continuous with the tubuli seminiferif and constitute the vasa 
recta, while the rest abort. The Wolffian duct thus becomes 
the vas deferens, or excretory duct of the testis; and its 
anterior end, coiling on itself, gives rise to the epididymis, 
A vesictda seminalis is a diverticulum of the vas deferens, 
near its posterior end, which serves as a receptacle for the 
semen. 

If the Wolffian bodies, the genitalia, and the alimentary 
canal of a vertebrate embryo, communicated with the exterior 
by apertures having the same relative position as the organs 
themselves, the anus would be in front and lowest, the Wolf- 
fian apertures behind and highest, and the genital apertures 
would lie between the two. But the anal, genital, and uri- 
nary apertures are found thus related only among certain . 
groups of fishes, such as the Teleostei, In all other Verte^ 
hraia, there is either a cloaca, or common chamber, into 
which the rectum, genital, and urinary organs open ; or, the 
anus is a distinct posterior and superior aperture, and the 
opening of a genito-urinary sinus, common to the urinary 
and reproductive organs, lies in front of it, separated by a 
more or less considerable perincBv/m, 

These conditions of adult Vertehrata repeat the states 
through which the embryo of the highest vertebrates pass. 
At a very early stage, an involution of the external integu- 
ment gives rise to a cloaca, which receives the allantois, the 
ureters, the Wolffian and Miillerian ducts, in front, and the 
rectum behind. But, as development advances, the rectal 
division of the cloaca becomes shut off from the other, and 
opens by a separate aperture-— the definitive anu^s, which thus 
appears to be distinct, morphologically, from the anus of an 
osseous fish. For a time, the anterior, or genito-urinary part 
of the cloaca, is, to a certain extent, distinct from the rectal 
division, though the two have a common teTinma.^\oTL\ «sA 
tbj8 condition is repeated in Aves, and in oTm\^cA<^^oA\& 



no THE A.NATOMY OP VEHTEBHATBD ANIMAXS, 

MamiriaUo, where the bladder, the genital duota, and tha 
uretera, all open separately from the reetnm into a genito« 
minary sinuB, 

In the male sex, aa development advances, this genito- 
urinary einuH beeomoB elongated, muscular, and anrronnded, 
where the bladder passes into it, by a peculiar gland, tlia 
proetate. It thus becomes converted into what are termed the 
fii/ndas.aai neekqflhe bladder, v/ith the prostatic and»w»- 
branotu portions of the urethra. Concomitantly with tbeM 
changes, a procesB of the ventral wall of the cloaca i 
ite appearance, and is the rudiment of the introndttait 
organ, or penis. Peculiar erectile vascular tisane, devdopefl. 
■within this body, gives rise to the median corpus spon^ 
and the lateral corpora cavernosa. The penia graduall; pro- 
trudes from the cloaca ; and wliile the corpus spon^iomB 
terminates the anterior end of it, as the gtana, the corpcn 
<javerno8a attach themselves, posteriorly, to theiacftid. ~ 
uiider,' sr posterior, surface of the penis is, at first, eiinplf 
grooved ; by degrees, the two aides of the groove unite, and 
form a complete tube embraiced by the corpus spongiosum. 
The penial wrethra is the result. 

Into the posterior part of tins peniot urethi'a, which ia frer 
qnently dilated into the ao-called bnlbiig mrethrce, glaadft 
lialled Covspefs gla'iids, commonly pour their aecretion; 
tbe peuial. membranous, and prostatic portions of tJiB 
urethra (genito-urinary sinus) uniting into one tube, tlla 
male dijimlive vrcthra is finally formed. 

In sundry birds and reptiles, the penis remaina i 
condition of a process of the ventral wall of the cloacai 
grooved on one face. In omithodelphous mammals tlul 
penial urethra is complete, but open behind, and diatijMt 
from the genito-uiinary sinus. In the Didslphia the penial 
urethra and genito-urinary sinus are miited into one tuhei 
but the corpora cavernosa are not directly attached to tbi 

Certain Rejitilia possess a pair of eversible copulatoij 
organs situated i» integumentaiy sacs, one on each aide 
the cloaca, but it doea not appear in what maoner Uie 



MODIFICATIONS OF THE BEPBODUGTIYE ORGANS. Ill 

penes are morphologicallj related to those of the higher 
Vertebrata, 

In the female sex, the homologue of a penis ireqnently 
makes its appearance as a clitoris, but rarely passes beyond 
the stage of a grooved process with corpora cavernosa and 
corpus spongiosum — ^the former attached to the ischium, and 
the latter developing a glans. But, in some few mammals 
(e, g. the LemuHdoeJ, the clitoris is traversed by an urethral 
canaL 

In no vertebrated animal do the ovaries normally leave the 
abdominal cavity, though they commonly forsake their 
primitive position, and may descend into the pelvis. But, in 
many mammals, the testes pass out of the abdomen through 
the inguinal canal, between the inner and outer tendons of 
the external oblique muscle, and, covered by a fold of peri- 
toneum, descend temporarily or permanently into a pouch 
of the integument — ^the scrotum. In their course they be- 
6ome invested with looped muscular fibres, which constitute 
the eremaster. The cremaster retracts the testis into the 
abdominal cavity, or towai'ds it, when, as in the higher 
mammals, the inguinal canal becomes very much nan*owed 
or altogether obliterated. In most mammals the scrotal 
sacs lie at the sides of, or behind, the root of the penis, 
bat in the Didelphia the scrotum is suspended by a narrow 
neck in front of the root of the penis. 

In most mammals the penis is inclosed in a sheath of 
integument, the preptititun ; and in many, the septum of the 
corpora cavernosa is ossified, and gives rise to an os penis, 

I In the female the so-called labia inajora represent the 
KTotal, the labia minora the preputial, part of the male 
organ of copulation. 
Organs not directly connected with reproduction, but in 
^ Tarious modes accessoiy to it, are met with in many Vcrte- 
] (rata. Among these may be reckoned the integumentary 
' pouches, in which the young are sheltered duidng their 
development in the male Pipefish {Syngmithus), in some 
female Amphibia {Notodelphys, Plpa), and Marsupialia ; to- 
gether with the mammary glands of the Mammalia. 



112 THE ANATOMY OF VBETEBBATBD ANIMALS. 



CHAPTER III. 

THE PROVINCES OF THE VERTEBRATA — THE CLASS PISCES. 

The Vertebrata are divisible into three primary groups or 
provinces : tlie Ichthyopsida, the SawopMa, and the Mam- 
malia, 

I. — The Ichthyopsida 

> 

1. Have the epidermic exoskeleton either absent, or very 
slightly represented. 

2. The spinal column may persist as a notochord with a 
membranous sheath, or it may exhibit various degrees of 
chondrification or ossification. When the vertebrae are dis- 
tinct their centra have no epiphyses. 

3. The skull may be incomplete and membranous, more 
or less cartilaginous, or osseous. When membrane bones 
are developed in connection with it, there is a large para- 
sphenoid. The basi sphenoid is always small, if it be not 
absent. 

4. The occipital condyle may be absent, or single, or 
double. When there are two occipital condyles they belong 
to the ex-occipital region, and the basi-occipital region is 
unossified or very imperfectly ossified. 

5. The mandible may be absent, or be represented only 
by cartilage. If membrane bones are developed in con- 
nection with it, there is usually more than one on each side. 
The articular element may be ossified or not, and may be 
connected with the skull by the intermediation of a quadrate 
and a hyomandibular element, or by a single fixed plate of 
cartilage representing both these and the pterygo-palatine 

areli. A stapes m-dj be present or absent. 



THE SAUBOPSIDA. 113 

6. The alimentary canal may or may not terminate in a 
cloaca. When there is no cloaca the rectum opens in front 
>f the urinary organs. 

7. The blood-corpnscles are always nucleated, and the 
leart may be tubular, bilocular, or triloculai*. 

8. There are never fewer than two aortic arches in the 
idult. 

9. Respiration takes place by branchiaB during part, or 
Jie whole, of life. 

10. There is no thoracic diaphragm. 

11. The uriiiary organs are permanent Wolffian bodies. 

12. The cerebral hemispheres may be absent, and are 
aever united by a corpus callosum. 

13. The embryo has no amnion, and, at most, a rudi- 
ootentary allantois. 

14. There are no mammary glands. 

n. — ^The Sauropsida 

1. Almost always possess an epidermic exoskeleton in the 
form of scales or feathers. 

2. The centra of the vertebrsB are ossified, but have no 
terminal epiphyses. 

3. The skull has a completely ossified occipital segment, 
and a large basisphenoid. No separate parasphenoid exists 
in the adult. The pro-otic is always ossified, and either 
Temains distinct from the epiotic and opisthotic through- 
out life, or unites with them only after they have anky- 
loBed with adjacent bones. 

4. There is always a single, convex, occipital condyle, into 
▼liich the ossified ex-occipitals and basi-occipital enter in 
Tarious proportions. 

5. The mandible is always present, and each ramus con- 

littB of an articular ossification, as well as of several mem- 

Imne bones. The articular ossification is connected with 

the skull by a quadrate bone. The apparent " ankle-joint " 

b ntnated, not between the tibia and the astragalus, as in 

^Mammalia, but between the proximal and the distal divi- 

taoDB of the tarsus. 

I 



11-1 THE ANATOMY OF VEETKBKATED AHIUALS. I 

6. The alimentary canul tenntiiatoB in a cloaca. 

7. The heart is trilocular or quadiTlocular. Some of tlic 
blood-corpusclea are always red, oval, and nucleated. 

8. The aortic arches are losually two or more, but tnnj b« 
reduced to one, which then helonga to tbe right side. 

9. Reapii-ation is never effected by means of branchis, 
liut, after birth, is performed by lungs. The bronchi 3o 
not branch dichotomoualy in the lungs. 

10. A thoracic diaphragm may exist, but it never f omu 
complete partition betwefin the thoracic and the abdominl 

11. The Wolffian bodies are rejilaced. functionally, hj 
permanent kidneys. 

12. The cerebral hemiapherea are never united by a corpus 
callosuni. 

13. The reproductive organs open into the cloaca, 
the oviduct is a Fallopian tube, which presents an uterine 
dilatation in the lower pai-t of its course. 

14. All are oviparous, or ovoviviparous. 

15. TUe embryo has an amnion, and a large rt-spiratury 
aliantois, and is developed at the eixwi^e of the 
vitellus of the egg. 

16. There are no mammary glanda. 

III.— The Hammalla 

1. Always possess an epidermic exoskeleton in the lona ot 

2. The vei-tebne are ossilied, and [except in the Oi-nttiwt 
delphia) their centra have terminal epiphyses. 

3. AH the segments of the bratn-caae are com.pl«te|f 
ossified. No distinct parasphenoid exists ii ' 
The pro-otic osaifies, and unites with the epiotic and opi^ 
thotio before these coalesce with any other bone. 

4. TTiere are always two occipital condyles, and the baai- 
occipital is well ossified. 

5. The mandible is always present, and each i-amna cwn- 
sists (at any rate, in the adult] of a single membrane bom 
which articulates with the squamuaal. The quadrate boo^ 



" THE CLASS PISCES, 115 ' 

Lnd ibe supra-Btapedial element of tlie hjoidean arch, t 
onverted into a. malleua imd lui incus, so that, with the 
tapes, there are, at fewest, three on^ieuia audiltis, 

1). The aJimectar]' canal tnaj, ur muy not, terminate in a 
:loaca. When it does not, the rectum opens behind the 
fenito-ttrinary organs. 

7. The heart ia ijaudrilocular. Some of the blood-eor- 
iiisclea are olwajs red and non-nunleated. 

8. Tliereia onlyone aortic arch, which liesou the left aide. 
0. Beapiratiou ia never effected by means of hranchia;. 

■lit, aft^er birth, ia performed hy lungs, 
ll). There is a complete diaphragm. 

11. The Wolffian bodies are replaced by permanent 
kidneys. 

12. The oerebral hemispheres are united hy a corpus cai- 

13. The reproductive organs may, or may not, open into 
a cloaca. The oviduct is a FiUlopian tube. 

14. The embryo has an amnion and au allantois. 

15. Mammary glands supply the young with nourialiment. 

Tlic Ichthyopsida, — Class I, — Pisces. 

The class of Pishes contains animals which vaiy so mneh 
ia their grade of organization, and iu their higher forms 
-I flosely approach the Amphibia, that it is difficult to 
■Liw up any definition which shall be at once character- 
-L'.' and diagnostic of them. But they are the only ver- 
■'iiited animals which possess meiliau fins supported by 
Ill-rays; and in which the limbs, when present, do not 
'■'hihit that division into brachium, antebrachium, and 
ninus which ia found in all other Verlebrata. 
The presence of the peculiar integumentary organs eon- 
'!iitingwhat is known as the system uf mucous canals and 
i"':-:^an3of the lateral line (supra, p. 86), ia highly charac- 
■i^tic of Fishes, though these organs cannot be said to 
l^^l in the entire class. 

'■'he cUes Pisces is diviaible into the folluninj 



on no skull, brain, oudUa 



i of the body. Then 



3 ASATOMY or VEETEBEATED i 



JIUALS. 



higher Veritbrota. The heart is a simple tube, Mud the UtB 
saccular. (Leptocahdia, Haeckel). 
1 . — Fliaryngobranchii. 
B. Th(! nolochord ends behind.the pitailar)' (bsBtt. A skull, br«iii. 
ditory, and rcoal organs are developed. The hear! is divi 
into aiuicular and ventricular chambers. Tlic liver hu tht 
ordinary atructure (Pachycahdia. Hck.). 
a. The nasal sac is siaele, and has a median extenul 
aperlure. NellheT mandibles nor limb arches aredtci- 
loped {Monorhma. Hck.). 
II.— ManijivbraiuJiU, 
b. TherearetwonasalsacBwUhBepBrBlo apertures. MandibM 
and limb arches are developed. (^w/iftirAina. U 
a. The nnasl passages do not communicsle with the cavilf 
of the mouth. There are do lungs, lad tbi "- — 

a. Tho skull Is devoid of membrano bones. 
p. Membrane hones are developed in relatie 



!, The optic nerves i 



VI,- Dijmoi. 

I. The Phakyngobeanchii,— This order contains 
one Bpeciea of fieh, the remarkable Lancelet, or AmphU 
lanceolatua, whieh lives ia Hand, at moderate depths in 
Hea, in many parts of the world. It ia a email 
parent creature, pointed at both ends, as its aajue implin 
and poBseBsing no limbs, nor any hard epidermic or 3aB 
covering. 

The dorsal and caudal regions of the body preBcnt 
low median fold of integument, which ia the sole repTMCtf 
tfltive of the system of the median lins of other fishes. '~ 
mouth (Fig. 28, A, a) is a proportionally large othI t^ 
ture, whi:;h lies behind, as well as below, the anteriw 
mination of the body, and has ttH long axis directed 1« 
tudinally. It« margins arc produced into delicate 
tentacles, supported by semi- cartilaginous filaments, w] 



THE PHARysaOBKANCHlI. 



1171 



are attached to a hoop of the same texture placed around 1 
the margiiiB of the mouth (Fig. 29,/. g). These probably I 
represent the labial cartilages of other fishes. The ural''! 
aperture leads into & large uud dilated phaiyux, the widlB> I 
of mhifh are perforated by nunieroua clefts, and richly J 
ciliated, bo that it resenibleB the pharynx of an Aacjdian •] 
B, /, g). This great pharyni is connected witb 
mple gastric cavity which passes into a straight intes- i 




—Aa^hkaiu laaceolalu: — a, nioutli; b, pharyngobranchiul 
ler ; e, tnua-, il, liver; e, nbdinnlnul pore.— B, the hcul en- 
: o, the naluchord; b, tho repreaeutiitives uf ucurat Bpliie 
-TBJV: s, the jolnled oral fing; rf, Ihe Hlamentary apiiendng' 
mouth; F, the ciliated lobea of the phiirjFQx-,/, jr, part uf tt 
lial nc J A, the spiaii cord. 

tine, ending in the anal aperture, which is situated st th6 ■ 
root of the tail at a little to the left of the median line 9 
iFig. 28, A, e). The mucous membrane of the intestine ia J 

1 aperture called the abdominal pore (Pig. 28, A, e),\ 
' 1 front of the anus, leads into a relatively spaciowi 



118 THE ANATOMY OF VERTEBBATED ANIMALS. 

cavity, which is continued foi-warde, on each side of the 
phaiynx. to near the oral upei-tlire. The water which is 
constantly propelled into the pharjni by its cilia, and ihoee 
of the tenta^ea, is driven out through the branchial defts. 
and makes its exit bj the abdominal pore. 

The liver (Fig. 28, A, d) is a saocnlar divertifnlnm of the 
inteatine. the apes of which is tumed furwarda. 




5^- 




Kip, W.— AnlBiior end of the body of Awphiaxtit :— Ch, notoiJiaril 
Jl^, Tuyelon, or ipinal ehoid : a, position of olfutorj (i')9»c; b, cfilM 
nerve ; c, fiAh (?) pair; d, spinal nerves; e, representative* ofnMI- 
nil spines, or fln-raja ; f, j,, oral (keleion. The ilehler and duka 



Tlie existence of distinct kidneys Sh doubtful ; and the pb- 
productive organs ai'e simply quadrate gland»ilv mamc 
attached in a row, on eaeh aide of tlie walls of the viscer 
cavity, into which, when ripe, they ponr their contenta. 

The heart retains the tubular condition which it poseesMl 



THE PHAKYNOOBEANCHII. 119 

in the earliest embryonic stage only, in other Vertehrata. 
The blood bronght back from the body and from the ali- 
mentary canal enters a pulsatile cardiac trunk, which runs 
along the middle of the base of the pharynx, and sends- 
branches up on each side. The two most anterior of these 
pass directly to the dorsal aorta ; the others enter into the 
ciliated bars which separate the branchial slits, and, there- 
fore, are so many branchial arteries. Contractile dilata- 
tions are placed at the bases of these branchial arteries. 
On the dorsal side of the pharynx the blood is poured, by 
the two anterior trunks, and by the branchial veins which 
carry away the aerated blood from the branchial bars, into 
a great longitudinal trunk, or dorsal aorta, by which it is 
distributed throughout the body. 

Notwithstanding the extremely rudimentary condition of 
the liver, it is interesting to observe that a contractile trunk, 
which brings back the blood of the intestine, is distributed 
on the hepatic sac after the manner of a portal vein. The 
blood is collected again into another contractile trunk, which 
represents the hepatic vein, and is continued into the cardiac 
trunk at the base of the branchial sac. The corpuscles of 
the blood are all colourless and nucleated. 

The skeleton is in an extremely rudimentary condition, 
the spinal column being represented by a notochord, which 
extends throughout the whole length of the body, and ter- 
minates, at each extremity, in a point (Fig. 28). The in- 
vestment of the notochord is wholly membranous, as are 
the boundary- walls of the neural and visceral chambers, 
so that there is no appearance of vertebral centra, arches, 
or ribs. A longitudinal series of small semi-cartilaginous 
rodlike bodies, which lie above the neural canal, represent 
either neural spines or fin-rays (Fig. 28, B, 6). Neither is 
there a trace of any distinct skuU, jaws, or hyoidean appa- 
ratus ; and, indeed, the neural chamber which occupies the 
place of the skull, has a somewhat smaller capacity than a 
segment of the spinal canal of equal length. 

There are no auditory organs, and it is doubtful if a 
ciliated sac, which exists in the middle line, afc \^ifc i^oti^ 



120 THE ANATOMY OP VEETEBBATED ANIMALS. 

part of the cephalic region (Fig. 29, a), ought to be con- 
sidered as an olfactory organ. 

The myelon traverses the whole length of the spinal 
canal, and ends anteriorly without enlarging into a brain. 
From its rounded termination nerves are given off to the 
oral region, and to the rudimentary eye or eyes (Fig. 29, 
6, c). 

According to M. Kowalewsky,* who has recently studied 
the development of Amphioitus, the viteUus undergoes com- 
plete segmentation, and is converted into a hollow sphere, the 
walls of which are formed of a single layer of nucleated cells. 
The wall of the one moiety of the sphere is next pushed 
in, as it were, until it comes into contact with the other, 
thus reducing the primitive cavity to nothing, but giving 
rise to a secondary cavity, surrounded by a double mem- 
brane. The operation is, in substance, just the same as that 
by which a double nightcap is made fit to receive the head. 
The blastodenn now acquires cilia, and becomes nearly 
spherical again, the opening into the secondary cavity being 
reduced to a small aperture at one pole, which eventually 
becomes the anus. M. Kowalewsky points out the resem- 
blance, amoimting almost to identity, of the embryo at this 
stage with that of many Invertehrata. 

One face of the spheroidal blastoderm becomes flattened, 
and gives rise to lamince dorsales, which unite in the charac- 
teristically vertebrate fashion ; and the notochord appears 
between and below them, and very early extends forwards, 
beyond the termination of the neural canal. The neural 
canal remains in communication with the exterior, for a 
long time, by a minute pore at its anterior extremity. The 
mouth arises as a circular aperture, developed upon the 
right side of the anterior end of the body, by the coalescence 
of the two layers of the blastoderm, and the subsequent 
perforation of the disc formed by this coalescence. The 
branchial apertures arise by a similar process, which takes 
place behind the mouth ; and they are, at first, completely 

* * Memoires de rAcademic Imperiale dcs Sciences de St. Peters- 



THE HASSirOBRANCHlI. 121 

>d on the anrface of the body. But, before long, a 
admal fold is developed upou each side, and jrrowB 
ibe bi-aachial aperturea. The two folds eventually 
be on the ventral eide, leaving only the abdominal 
}pen. One cannot but be Btmck with the i-esem- 
► of tbeae folds to the proceaaea of integument which 
over the hvanchise of the amphibian larva ; and, in 
tanner, incloae a cavity, wUich conimunieatea with the 
w only by a single pore. 

: great many of the characters which have been enu- 
id — as, for example, in the entire absence of a distinct 
fnd brain, of auditory organs, of kidneys, of a eham- 
ieart; in the presence of a saccular liver, of ciliated 
tueand alimentary eanal; and in the extension of the 
tord forwards to the anterior end of the body — Aiitfhi- 
Sffera from every other vertebrated animal. Hence 
teor Haeckel has proposed to divide the Verlehraia 
two pnmary groups — the Leptocairdia, containing 
!oa«i«,- and the PixeKycardia, comprising all other 
rata. The great peculiarities in the development of 
knFiM, and the many analogies with invertebrate ani- 
partifiularly the Ascidiana, which it presents, lend 
Support to this proposition. 
toBsil form allied toAmphioxus is known. 

rhe MABSiPOBEAHCHn. — In this order of the class 
the integument is devoid of scales or bony plates. 
spinal column consists of a thick persistent notochord 
>ed in a aheath. but devoid of vertebral centra. The 
arches and the riba may be represented by carti- 
nd there is a distinct skull presenting cartilage at 
its base, and retaining many of the characters of 
btJ cranium of the higher Yertebrata. The notoebord 
bt«s in a point in the base of this cartilaginous skull 
the pituitary body; and the skull ia not moveable 
spinal column. There are no jaws; but the palato- 
oid, the quadrate, the hyomandibular, and the hyoi- 
;U8,of higher Yertebrata, are imperfectly repre- 



sejited(rig. 30,/ g, h). In some genera abasket-Uke carti' 

laginoni apparattiH strengthens the walls of the or&l cavitji 

while, in others, such a framework aupporte the giU- 

The MantipobTtmchii poHseBs neither tJie pectoral 



the 




Fig. 30.-A, the skull uf a Lamprey, viewed fri.m tiie aide; B, from 
above 1— o, the ethmovomorine plate ; b, liie olfoolory lapsule ; c, tha 
oudiCury capaule; tf, the neural arches of the epliiul iMiliimn j e, the 
pjilato-pterygoid pordoE,/, probably, the metapterjemd, or superior 
qnadrate, portiou, and g, the inferior ijuadrate portion, of Ibe 
■ubooular arch; A, styluhyal procesa; i, lingual cartilage; i, in- 
ferior, I, lateral, prolongation of the cranial cartila^ ; 1, 3. 3, 
acceBEory Inbial CBrtllagcB; m, hninchial skeleton. The spares ou 
either side of I are closed by membrane. 

pelvic pair of hmba, nor their arehea. Horny teeth may be 
developed upon the roof of the palate, or upon the tongue, 
or maj be supported by peculiarly developed labial carti- 



THE MABSIPOBBANCHII. 123 

lages. The aHmentary canal is simple and straight, and 
the liver is not sac-like, but resembles that organ in other 
Vertebrata. 

The heart has the usual piscine structure, consisting of 
a single auricle preceded by a venous sinus, a single ven- 
tricle, and an aortic bulb, 'all separated from one another by 
valves. This heart is contained in a pericardium, the cavity 
of which communicates with that of the peritoneum. 

In Myxine the portal vein is rhythmically contractile. 

The cardiac aorta, which is continued from the bulb, 
distributes its branches to the respiratory organs. These 
consist of antero-posteriorly flattened sacs, which commu- 
nicate, directly or indirectly, on the inner side, with the 
pharynx, and, externally, with the surrounding medium. 

In the Lamprey there are seven sacs, upon each side, 
which open externally by as many distinct apertures. Inter- 
nally, they communicate with a long canal, which lies beneath 
the oesophagus and is closed behind, while anteriorly it com- 
municates freely with the cavity of the mouth (Fig. 32, Pr). 

The kidneys are well developed, and have the ordinary 
vertebrate structure, while the ureters open behind the 
rectum. 

The brain, though very small, is quite distinct ' from the 
myelon, and presents all the great divisions found in the 
higher Vertebrata — that is to say, a fore-brain, mid-brain, 
and hind-brain. The fore-brain is further divided into 
rhinencephala, solid prosencephalic lobes, and a thala- 
mencephalon; the hind-brain, into metencephalon and mye- 
lencephalon (Fig. 31). 

The auditory organ is simpler than in other fishes, possess- 
ing only two semicircular canals and a sacculated vestibule 
in the Lamprey. In Myxine the whole organ is represented 
by a single circular membranous tube, without further dis- 
tinction into canals and vestibule. 

The Ma/rsipohranchii differ remarkably, not only from the 
fishes which lie above them, but from all other vertebrate 
animals, in the characters of the olfactory organ, which 
consists of a sac placed in the middle line of the head, and 




iT Pctromi/iDn jiuviali 
mbranous iBbyriDtb 
. ThefiillnnlDgletlerBreferdi theSeureBofthefanin: 
I, Ihe olfBctory nerves, oarrcm anlerior prolotiKBtiona of the i^iM 
cephslon (A) ; B, the prosencephalon ; 0, the Ihalnmenceidialon i 
the meiencepbslon ; 1., the medulla oblongata ; F, the ioiirtb n 
triole \ t, the nsrrotr band wliich b all that reprneiita (he oeiebdhn 
G, the ipinal cord; Tl. the optic; III. the oeulomnturius; IV. the p«] 
HciU'iV.thetrigemiuiil; VI. Ihe ahduccna; VII. thetaHal, udl 
aaditory; VIII. the gloiinptaaryngeal «nd piieumognslrie ; IX. I 
bn'ogl'i*^! nerves; 1, 1', 2, V, senioTy and niittiir roots of tM ft 
two^nal nerves. In the flgure ol' the raembranotia labTrinthl 
the auditory nerve; a, the reatlbule; c. the lwi> leml circular oaM 
which correiponil with the inlerior and posterior rertlcal cuuk 
other VerUbrtita ; d, Iheir union aud lommon opening into tfce V 
tlbule; t, the ampullE. 



THE HARSIPOBKANCHII 



125 1 



Buigte, median, extemul aperture. la tUl other I 
iebrata there are two naaal BiuiB. Ill the Lamprejs, the 1 
t terminatee blindlj below and behind, but In 
Hags [Myxine), it opens into the pbai-ynx. In no other | 
fishes, except Lepido»ireti, doea theoliaetorj apparatus m 
miinicate with the cavity of the month. 

The reproductive organs of the Marsipobranchii are solid 
plates suspended beneath the spinal cohimn, and the? have 
no ducts, but shed their contents into the abdomen, whence 

Fig. 38. 




[. 38— Vertical and lonKiludinal secljon of the anlerior pi 
lodj i>f k LUDprey (Petronycon nariniu) : — A, the crsni 
"l Goutained brain ; a, wction of the edge of the cartilage marked i 
io F^.30; Olf. entrance into the olfactory chamber, which li ] 

roloDged into the cebchI pouch, d ; Ph, the pharyni; Fr, tho 

SDtduki Bhunnel. with the inner Bp«rtureB of the brandliiul saos ; 

I, Ihe Mvity of the mouth, with Irs horny teeth ; 2, the cartilage I 

Ueh supports the tongue; 3, the oral ring. 

J pass out by an abdominal pore. In the early atages o£ \ 
ir developiiient the Lampreja present some singular 
kUsnoes to the Amphibia. Thej aleo undergo a mettuuor- I 
leia, the young Peiramysoti being so unlike the parent, ■ 
t it was, until lately, regai-ded as a diatiuct genus — I 
But the yonng Lampreys never poa, 
branchial filamenta or apiracula. 
!he Marsipobranckii are inhabitants of both fresh and J 
( water. The Mysinoids are remwliahle for their parasitio |l 
Hag boring ite wfty into tlie bodies ot oth 



126 THE ANATOMY t 

fiahes, Buch ae tte Cod. No fossil Marmpobranchii lae 
known. Thia circiimBtauce may, in part, be due to the 
perialiableneaa of their bodies ; thuugh homy teeth, like 
those cif the Lampreys, might hava been preserved under 
favourable circtimBtancea. 

III. The EiASMOBRANCHii. — This order contains the 
Sharka, the Rays, and the Chimaera. 

The integument may be naked, and it nerer possesses 
acalea like thoae of ordinary fishes ; but, very oommonlj, it 
is developed into papilhe, which become calcified, and give 
rise to toothlike stracturea : these, when they are veiy 
email and cloae-aet, constitute what ia called shagreen. When 
larger and more scattered, they form dermal plates or 
tubercles; and when, as in many cases, they take the form 
of spines, these are called dermal defences, and. in a faeail 
state, iohtkyodondites. All these constitute what has been 
called a "-placoid exoaJtehton ;" and, in minute struetnre. 
they precisely resemble teeth, as has been already explBined. 
The protruded surfaces of the dermal defences are fre- 
quently ornamented with an elegant sculpturing, which 
ceaaes upon that part of the defence which is imbedded in 
the skin. The dermul defences are usuaJly implanted in 
front of th^ dorsal fiua, hut may be attached to the tail, or. 
in rare cases, lie in front of the paiiiid fina. 

The apinal column exhihita a gi'eat diversity of atructUM: 
from a persiatent uotochord eihibiting little advance upon 
that of the MaraipobrancMi, or having mare oaseoiis rinei 
developed in ita walls, to complete vertebne, with deqi 
conical anterior and poaterior (wncavitiea in their centra. 
and having the primitive caj-tilage more or less complete 
replaced by concentric, or ■■adiatiug. lamelhe of bone. la 
the Rays, indeed, the ossification goes so far aa to convert 
the (Ulterior part of the vertebral column into one con- 

The neural arches ai'e sometimes twice as numerous as 
the centra of the vertebne, in which case the added i 
are termed intercrural cartilages. 



THE ELASMOBBANCHII. 127 

The terminal part of the notochord is never enclosed 
within a continuous bony sheath, or wrosdyle. The ex- 
tremity of the vertebral column is generally bent up, and the 
median fin-rays which lie below it are, usually, much longer 
than those which lie above it, causing the lower lobe of the 
tail to be much larger than the upper. Elasmobranchs with 
tails of this conformation are truly heterocercal, while those 
in which the fin-rays of the tail are equally divided by the 
spinal column, or nearly so, are dvphycercal (p. 16). The 
Monkfish (Squatina) and many other Elasmohranchii are 
more diphycercal than heterocercal. 

The ribs are always small, and may be quite rudimentary. 

The skull is composed of cartilage, in which superficial 
pavement-like deposits of osseous tissue may take place, 
but it is always devoid of membrane bone. When move- 
able upon the spinal column, it articulates therewith by 
two condyles. 

In its general form and structure, the cartilaginous skull 
of an Elasmohranch cori'esponds with the sktdl of the verte- 
brate foetus in its cartilaginous state, and there are usually 
more or less extensive membranous f ontanelles in its upper 
walls. The ethmoidal region sends horizontal plates over 
the nasal sacs, the apertiu*es of which retain their em- 
bryonic situation upon the under-surface of the skull. 

Neither premaxillsB nor maxillse are present, the " jaws " 
of an Elasmohranch consisting, exclusively, of cartilaginous 
representatives of the primary palato-quadrate arch and of 
Meckel's cartilage. 

The former of these, the so-called upper jaw, may either 
be represented, as in the Chimcera (Fig. 33), by the anterior 
portion {B, D) of a triangular cartilaginous lamella, which 
stretches out from the sides of the base of the skull, and is 
continuous with the representative of the hyomandibular 
suspensorium ; or there may be, on each side, a cai-ti- 
laginous bar moveably articulated in front with the fore 
part of the skull; and, posteriorly, furnishing a condyle, 
with which the ramus of the lower jaw, representing Meckel's 
cartilage, articulates. 



128 THE ANATOMY OF VESTEBRATED AKIMALB. 

Iq the latter caae, which la that met with in the Shaitfl 
and Rays (Pigs. 34 & 35), a single cai-tUaginoua rod (j) ii 
moveahly artieuiated with the skull, in the r^on of the 
periotic capsule, upon each side; and, by it^ opposite ei- 
tremity, is connected by ligamentous fibres hotL with tie 
palato-quadrate (h), and with the mandibular or Meckeliui 
eartilage (Mn). This caiiilaginoua sitspeneoriam repreaent* 




Tig. 33.— VETllcal scclion i>f (he ahull of Clilmaa moiulroat, wilhmit 
the Ubial and nasal CBrtllBgee :— il, tbe basi-occipilal region; P, 
the piCuituy fo>sa ; Na, partition jjelween the oltai^iory Met; B, 
BlTeolna for the unterior upper jaw tooth ; C, D, the Tegiaii ortlw 
trluiguiar ciirlilage which answers to Che hyinandibalBr aad qtttd* 
rute; D, B. that which aniwers to the quadrate, ptcrvBind, Ud 
palatiae ; Mt, the mandible ; tOr. the Inlerorbital septum ; <1M ud 
ptc, the anterior and posterior aeiniclrcular canals; I., II., v., TUL. 
exits lit the oltactory, optic, fifth and eigtith pairs of nerves. 

the hyomandibular and the b jmplectie bones of the TtUodti, 
and gives attachment to the hyotdean appiuutua (Hy). Tlw 
latter consiHte of a lateral arch upon each side, united witb 
its fellow, and with the branchial arches, by the intermedii- 
tion of medial basal elements below; and it is suoce^M 
bj a variable number of similar arches, which support Um 
lu'aachial appariituB. 



1 the bjoidean and from the branchial ai'chea cui'ti- 
la filameuts pass directly outwards, and support the 
a of the branchial sacs. Superficial cartUagea, which 
lie piiraUel with the branchial ai^^hes, axe sometiiuea super- 
ioip^jsed upoa theae. There are do opercular bones, though 
cartilaginoua filaments which take their place (Fig. 34, Oj>) 
inaj be connected with the hjomaikdibutar cartilage; and. i 
in the great majority of the EUumobrarmhii, the apertures 
of the giU-aaca are completely eipoaed. But in one group, 
the CkinuBra, a great fold of membrane eitenda back from | 
the BUBpeuBorial apparatus, and hidea the external gill- 
Large acceaaorj cartilages, called laiial, are developed at 
the sidea of the gape in many jElasmatranckii. iFiga, 34 & 
35, i, k, I.) 

The pectoral arch canBiats of a single cai-tilage on each 
side. The two become cloaely united together in Uie ventral 
median line, and are not directly connected with the skull. 
The pelvis is also represented by a pair of cartilagea, which 
inay coalesce, and are invariably abdominal in poaition. 

There are always two pairs of lateral fins corresponding 
with the anterior and posterior limbs of the higher Verte- . 
hrala. The pectoral fins, the structure of which has already I 
Iweu described, are always the larger, and sometimes attain 
B enormons size relatively to the body. 

a these fiahes, teeth are developed only upon the mucous 
tnbrane which covers the palato-quadrate cartilage and 
k mandible. They ai'e never implanted in suoketa, and 
J vary greatly in form and in number. 
BtheBharke they are alwaya numerous, and their crowns ' 
« DBoaUy triangular and aharp, with or without serrations 
and lateral cusps. As a rule, the anterior teeth on each aide 
liave more acute, the posterior more obtuse crowns. In the 
Port Jackson shark (Cegtradon). however, the anterior teeth * 
% acut« than the most obtuse teeth of the others, 
; middle teeth ac<juire broad, nearly flat, ridged 
s. and the hindermost teeth are similar but smaller. 




r 

130 






















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ffif 




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Ill 



ie Rays uaoa.llj' have Eomewliat obtusely-pointed teath, but 
Myliobateii,ihe middle t«etU httve trausvereely elouguted, 
d the lateiul ones Lexagoual. fla.t crowns, and the variouB 
teetli are fitted ploaely by their edges into a. pavement. In 
Aetobatis only the middle tranaveraeiy elongated teetli re- 
main. In the Sharks and Bn.ya the teeth are developed from 
papilla, or ridges, situated iLt the bottom of a, deep fold 
within the mucona membrane of the jaw. The teeth come 
to the edge of the jaw, and, as they are torn away or worn 
down by use, they are replaeed by others, developed, in ene- 
ceasive rows, from the bottom of the groove. No such 
successive development takea place in the ChimtEra, 

As in other fiahea, there are no aaJivary glands. The 
wide oiaophagiia leads into a stonuieh which is usually 
spacious and Hac-Uke. bnt sometimea, aa in Chimeera, may 
be hardly diatinct from the rest of the alimentary canal. 
No diverticulum filled with air, and constituting a swim- 
ming-bladder, as in Ganoid and many Teleosteun fishes, is 
'.'■nnet'ted with either the cosopbagus. or the atomach, 
(ihougli a rudiment of this Btructui'e baa lately been dia- 
□e iEUaaniobrancbs. 
: intestine is short, and usually commenced by a, 
latioB separated from the atomach by ii pyloric valvei 
is duodenal segment of the intestine is usually known aa 
ft Bursa Bntiana. It receives the hepatic and pancreatio 
(s, and, in the foetna, the vitelline duct. Beyond thin 
I. the absorptive area of the maeoua membi-ajic of the 
intestines is increased by the production of that 
iiiembrane into a fold, the so-called spiral valee, tlie fined 
<;i Ige of which nsually runs spirally along the wall of the 
inteetine. In some al^i'ka [Garcliuriag, Baleoeerdo) the fixed 
e of the fold rans sti-aight and parallel with the aiia of 
B intestine, and the fold is rolled up npon itself into a, 
lical spiiiil. 
e abort rectum terminates in the front part of a cloaca, 
pci) is common to it and the ducta of the renal and the 
idtictiTe organs. The peritoneid cavity 

1^ «£ tUe paricmrdiom in front, and. behind, opi 



I 



132 THE ANATOMY OP YEBTEBRATED AS 

externallj by two abdominal pores. The heart presents a 
single aYiricle, receiving the venona blood of the body trom 
a. airnia venoeus. There is a. Bingle ventricle, and the walls 
of the aortic bulb contain etriped muscular fibres, ajid are 
rhythmically contractile, pulsating as regularly as those of 
the auricle and ventricle. 

The interior of the bulb exhibits not merely a single row 
of valvea at the ventricnlo-bulboiiB aperture, but several other 



Fig. 36. 




B of eemilonar valves, which are attached bi 
the walls of the bulb itself, and at its junction with the 
:u>rta. These valves mast be of gi'eat importance in 
giving full effect to the propidsive force exerted by the 
muHcular wall of the bulb. 

In a good many ElaaTriobranehii there is a epiraele, or aper- 
ture leading into the cavity of the mouth, on the npper ai ' 
of the head, in front of the suHpensDrium, From this 
aperture (which, according to the observations of Professor 
Wyman, is the remains of the first visceral cleft of the 



THE ELASHOBRA-NCHIl. 



13S| 



embryol. as well as from the proper branchial cleftH, long I 
br&nchiaJ tUamente protrude, in the fcetui state. These I 
disappear in the adult, the reapiratoi'y organa of whiclt I 
are flattened pouches, with tranHTeraely-plaitod walla, front I 
five to seven in number. They open by eitemal cleft* I 
apon the sides (Sharks and ChimuBrd), or under-siirface 1 
fcaye), of the neck, and, by internal apertures, into the | 



, The anterior wall of the anterior sac \s supported by the I 
r.hjoidean arch. Between the posterior wall of the first, ajid I 
the anterior wall of the second sac, and between the ad- J 
jacent walls of the other saca, a branchial arch with it« | 
radiating cartilages is interposed. Hence the hyoidea 
arch supports one series of branchial plates or lamina 
while the succeeding branchial arches, except the last, bear 
two aeries, separated by a septum, consisting of the ad- 
jacent walls of two sacs with the interposed branchial 
skeleton. 

The cardiac aorta, a trunk whicb is the continuation of '] 
the bulb of the aorta, distributes the blood to the vessels of | 
these aacs; and it is there aerated by the water which ii 
taken in at the mouth and forced through the pharyngeal ,1 
apertures, outwards. 

The kidneys of the Klaamohratichii do not extend s< 
forward as those of most other fishes. The ureters gene- 
rally become dilated near their terminations, and open I 
by a common urinary canal into the cloaca behind the I 
rectum, 

e brain is well developed. It usually presents a large 1 

□ overlying the fourth ventricle, the side-walls of J 

I (corpora reniiformia) a*e singularly folded (Fig. 37, j 

i) ; and moderate-sized optic lobes, which are quite dis- I 

t fraia the conspicuous thalamencephalon, or vesicle of I 

d ventricle. The third ventricle itself is a I'elativelj 1 

e and short cavity, which sends a prolongation forwards, 1 

1 side, into a large, single, transversely-elongated I 

J. 37, a), wliieh is usually regarded aa the result o' 

al^cence of the cerebral heuiispherea, but is, perbajs, jl 



134 THE ANATOMY OF i, 




Fie. 37. -The brain of the Skala {Itaia talii). A. From ■ 
B. ApcFTtlon of thovcntrsl KBpcctenlnrgedi -«, (he olfactory bL.. . 
a, the cErebral hfrnisphetes which are united in the midalc Um; 
6, the thalamciicephalon : c, Iheniesenrephalon ; i/, the cerebellnni; 
EH, tlic plaiCcil bands torrned by the ciirpora reBliformia; i^ 11^ 
IV., v., the cerebral nerves ol' the correBponding |iBir» ; /, Ihe me- 



ary tody ; 



n i(..- cA, tl 



' cliligma of 



B of tl 



©re properly, to be conBidered 

D of the primitive eucephuJoi 

nalie and the hemiapbereH 

e large olfactotj lobes are uauaUj proli 
Ides, whicli dilate into great gangH 



the thickened termi 

1 which tlie lamina 

■ hardly differentiated. 

.ged into pe- 

where they 



ited.^^ 



) contact with the olfactory saeH (Pig. 37, A., 
le latter alwaya open npon the imder-Burfiice of the head. I 
eieft, which estenda from each nasal apertnre 
a of the gape, is the remaine of the euibryonii 
I between the naso- frontal proceaa and the maiilla-f 
ftlatine proeess, and representa the naso-palatine paes 
( the higher Vertsbrata. The optic nerves fuse into a ooia-| 

« chi&anui (Pig. 37, B.. eh), ae in the higher Verlebrata 
B some Sharks, the eye ie provided with a third eyelid o; 
ictitating meuibrane, moved by a aingle muecle. or by tffQtJ 
mselee, arranged in a. ma.oner Bomewbat similar to tlukt'>| 
lieerved in birda. In both Shai'ka and Rays, the posterii 
Face of the aclerotic presents an eminence which aTticnJ 
8 with the extremity of a cartilaginous stem prooeedinj 
n the bottom of the orbit. 
Eicept in. CAwiuBra, the labyrinth ia completely inclose 
I cartilage. In the Baya the anterior and poster' 
aemicircuUr " canals are circular, and open by distil 
r ducts into the veatibnlar sac. In the other Ela. 

i they are ajranged in the ordinary way. 
_ i leading from the vestibular aac to the top of thai 
bill, and opening there by a valvular aperture, representaj 
m canal by which, in the vertebrate embryo, the auditoryj 
ITolution of the integument is, at first, connected with tl 
[terior. 

The testes are oval, and are provided with an epididymia I 
dcferena, aa in the higher Vertebraia. The i 
of each aide opens into the dilated part o 
Attached to the ventral fins of the male are 
appendages, termed elaspers. 

ovaria are rounded, aolid organs. There are usually 
it in some caaes, as iji the Dogfishes and nictitating 
,^he OYHry is single and symmetrical. The oviducts 



13() THE ANATOMY OF VERTEBKATED 

are true FaUopiaa tubes, which conimimicate ft'eelj mtii 
the abdoiuinBJcavitjattlieir proximal ends. Distalljr, tliey 
dilate into uteiine chambers, which unite and open intotbt 
cloaca. 
The egga are very large, anil comparatively few, 
The Dogfishea, the Raya. and the Cliimmra are ovi- 
parous, and lay eggs enclosed in hard leathery caHes; th« 
others are yiviparoua, and in certain species of Jtfusleliu 
l&ms} and Coi'cAorwis, a rudimentai-y placenta ia formed, 
the vaBcular walls of the umbilical aac becoming plaited, 
find interdigitating nith similar folds of the wall of tiw 

The emhryoa of moat Elaamobi-ancha are, at first, pro- 
vided with long external branchial filamenta, which proceed 
from the periphery of the spimcle, as well as from moat of 
the branchial ai-chee. These disappear, and are function- 
aUy replaced by internal gills aa development advances. 

The Etasmohrwachii are divided into two groupa, tUi' 
Holtxephali and the Plagiogtomi. 

In the Holocepkali the palato-quadrate and suBpensorial 
cartilagea are united with one another and with the skull 
into a. continuous cartilaginous plate ; the branchial clefts 
ai-e covered by an opercular membrane. The teeth are 
very few in number (not more than aix, four of which are in 
the upper, and two in the lower jaw, in the living specieB) 
and differ in stracture from those of the Plagiostomi. Thii 
suborder contains the living CMmcera and CallorhyntK**, 
the ertinct ULenozola Edaphodon and Pasaalodop,; and, my 
probably, some of the more ancient ElaamobranohB, Ike 
teeth of which are S'l abundant in the Carboniferous lime- 
stones. 

In the PlagUietomi, the palato-quadrate and enspensorial 
cartilages are distinct from one another, and are moveable 
upon the akull. The branchial clefta are not covered by 
any opercular membi'ane. The teeth are usually numerona. 

The PlagionlmiU are again subdivided into the Shaiia 
(Selachii or Sqwili), with the bronchial apertures at the 



THE OANOIDEI. 137 

■ tbe bodj, the anterior ends of the pectoral fins not ci 
Cted with the skuU bj cartilages, and the akull with ft9 
1 facet for the &v»t vertebra ; and the Hajs [Bajie), ' 
bh the bi-ancliinl cltifta on the under-surface of the bodj, 
i pectoral fine united by cartilages to the akull, and no 
a articular facet upon the occiput for the first vertebra. 
The SlaemrAratickii are eseentiallj marine in their habita j 
lough Sharks are said to occur very high up in some 
le great rivet's of Soath America, 

Both divisions of the Plagiostomi occur in the Meaozi 
^8. In the Fulfeozuic epoch, dermal defences and teeth 
! EJaxawbranckii abound in the Permian and Carboni- 
s formations, and are met with in the Upper Silurian 
IB. But, except in the case of PfBuroeanfAus (a Selachian), , 
1 impoBeible to be certain to what special divisions tlief d 
iBong. 

IV. The Ganoidei.— In former periods of the world's 
istory thiti was one of the largest and most important of 
8 of fishes; but, at present, it comprises only the 
leTBi—Lepidodeue, Fvlypterm, Calanioieklhyg, Amia, _ 
', Scapirhytmhus, and SpatiiJaria, which are eithea: 
BtiaUy, or wholly, confined to freah water, and are foundl 
iJy in the northern hemisphere. These fishes differ verjTj 
ddy from one another in many points of their organizo*! 
, but agree in the following cliai'actera, some of whioh 1 
r poBseas in common with the Elatmobranchii, 
nrB with the Teleostei, Thus : — 

a. The buHms aortix is rhythmically contractile, and pro- 1 
ded with -several rows of valves, as in the EUismobranehii. I 

b. The optic nerves unite in a chiasma, as in the Elasmo- I 



I 

I 
I 



B. There is a well-developed spiral valve in the intestine I 
in lh6 Ela*mobraitJ:hii, in all but Lepidosteua, which pos- f 
»68 only a rudiment of such a valve, 
On the other hand — 
a. The branchial processes are not fi.ied throughout their I 
to tbe wall of a branchial sac, which extends b^oiu' 



138 THE ANATOMY OP VEBTBBRATED ANIMALS. 

them, aa in the Elasmdbranchii ; but their eitremities project 
freely beyond the edge of the Beptum which separatea eadi 
pair of branchial clefts, as in the Teleostei ; and, as in Uu 
Teleostei, they are covered by a bony operculuin. 

h. There is a large air-bladder connected by a, permv 
nentty open pneu'iimHc duct with the ceeophagus, am in. many 
Tehoatei. 

c, Ajs in the Teleodei, there is no cloaca. 

The ventral fins are always abdominal in position. The 
tail is diphycercal, or heterocercal, and the terminal XH>rtion 
of the notochord is not ossified. The cavity of the abdomen 




J Dieienoephslun ; 5. . 
ft, the pituitary body ; I, the lobi inferiorei 
factory ; II., uptio nerves. 



carebral hemisphere*; 



is placed in communication with the exterior by abdomin^ 
pores, PinaUy, the ducts of the reprodnctive organs ccan> 
municate with those of the permanent urinary appantoa. 
which is, in part, an Elasmobrancb, in part, an AnipMbion, 
character. 

The exoekeleton presents the most extreme variations in 
the Ganoid^. Bpatidaria is nalied ; Accipeneer and Sctgri- 
rhyneliiis develope ntimeruns dernial plates composed of true 
bone; Amia is covered with overlapping cycloid scnleB: 
J>pt(iffriW»I!di'o%pfenuhaveBolid,rhonifaoidal, enamelled . 



THE GANOIDEI. 139 

scales, whicli not only overlap, but are fitted together by 
pegs and sockets, where their anterior and posterior edges 
come into contact. 

The endoskeleton is not less diversely modified ; and it is 
worthy of remark that no sort of relation, either direct or 
inverse, is traceable between the completeness of the endo- 
skeleton and that of the exoskeleton. Thus Spatularia, 
SeapirhynchtbSf and Accvpenser have a persistent notochord, 
in the sheath of which mere cartilaginous rudiments of the 
arches of vertebrae appear. The ribs, when present, are 
partially ossified. Polypteinis and Amia have fully ossified 
Fertebrse, the centra of which are ainphiccelous. Lepidosteus 
also has fully ossified vertebrae ; but their centra are opis- 
thocoelous, having a convexity in front and a concavity 
behind, as in some Amphibia. 

More or fewer of the anterior vertebrae, or their cartila- 
ginous representatives, are united with one another, and 
with the posterior part of the skull. And the cranium may 
consist principally of cartilage, membrane bones being super- 
added; or the primordial cartilage may be largely super- 
seded by bone, as in the Teleostei, 

Spaiulariaf Scajpirhyrichvs, and Accvpenser have skulls of 
the former description. The cranium is one mass of car- 
tilage, continuous behind with the coalesced anterior spinal 
cartilages, so as to be immoveably connected with the spinal 
column. The notochord enters its base, and terminates in 
a point behind the pituitaiy fossa. In front, the cartilage 
is produced into a beak, which, in Spatularia, is very long, 
flattened, and spatulate. In the perichondium of the base 
of the skidl, median bones, answering to the vomer and to 
the parasphenoid of Teleostean fishes, are developed ; and, 
in that of its roof, ossifications, which represent the parie- 
tab, frontals, and other membrane bones of the Teleostei, 
appear. 

The framework of the jaws in Spatularia is very similar 
to that in the Elasmohranchii, There is a partly carti- 
laginous, and partly ossified, suspensorial cartilage {Aj B, 
Tig. 39), which gives attachment belo'w, 3ai^vi\\^, \.c> \)afc 



liO 



r VEBTEBRATED 



hjoidean arch (Hy) and, indirectly, to the jawa. The }att& 
conaiet of a palato-quadrate cartilage {D) united hj liga- 
ment with, its felltiw. and with the prefrontal region of Uw 
skull at F. ; and presenting, at its posterior end, a ooa- 
vex articular head to the cartilage of the mandible, or 
Meckelian cartilage, Mn. It is obvious that A, B corre- 
sponds with the hjonumdibular. or Buspeneorial, cartilage 
in the Sharks and Bays \ B, with the palato-quadrate carti- 

Fig. 39. 



] 




eipoiett ;— ^H, auditory ctiBinber ; Or, the orbit witb the eye; 
(he naenl ebc ; Ng, the Qyuidcan appnrstus ; Br, the TepreieoOl 
of flic braneliioiiteg»l rays; C(p, oiierculnm; jHn, mandible; J, i(, 
guspensorium ; D, paUto-quaiirale cartilage; J?, maiilla. 

lage, or so-called " upper jaw," and the cartilage of tie 
mandible with the lower jaw in these animals. But, i 
the Ganoid lish, an osseous operculum i^Op) is attached t 
the hyomandibular ; and a branchiostegal raj (Brj to lb 
moi-e strictly hyoidean part of the skeleton of the aecond 
visceral arch ; while a membrane bone (£) repreaeuting the 
maxilU, and another {Mn) the dentary, of the lower jaw in 
Teleostei, are developed in connection with the polato-qtiad- 
rate and mandibular cartilages. 



THE OANOIDEI. 141 

In tlie Sturgeon (Fig 40) the membrane bones of the 

rocrf of the Bknll are more nnmeroua uid distinct than in 

^oMarta and large dermal bones {J K L) are nnited 

wiUi them to form the great cephalic shield. The sugpen- 

Fig « 




fig- 40.— Tbe csrtilagintnie skull of a Sturgeon, with the cnniat bones. 
TIm Gurnet » tbaaed, and suppoeed to be aeen through the IstUr, 

which are F*'^ nna>IAflA<l . ^ J^Ano f.^wn<ut hi7 tIkA bninnnm nPAAADOA* 

Ai, porttion of the auditory orgMi; JVa, pi._. 
(fr.Uiat of orbit. Themembrane bones of the upper gurftca are : A, 
the analogue of the gupra-ocoipital ; S, B. of the ejnotios ; E, of the 
ethmoid; G, C, of the poatfruntalB ; /f, i/, of the prefrontBla ; C,C, 
tha parietalB ; D, J} are the frontale, and F, F the squamoBaJa ; K, 
the Ulterior dermal acute : /. / and L, L, dermal ouificatioBB con- 
□eeting the peot«ral arch with the ikull. 




Pig. 41.— Side-view of the carlilaginom cranium of .icc^miMr;— a, ros- 
trum: b, DBsal chamber; Or, orbit; c, auditor; region ; d, eoa- 
lesaed anterior vertebrs ; t, ribs;/, y. A, suspensoriiun; ^.palato- 
maxillary apparatus ; JIfii, mandible. 

soriaai ( f, g, k. Fig. 41) is divided into two portions, to the 
lower of which (at h) the proper hjoid is attached ; and the 
paUto-fosdrate cartilitgea, with their nibeidiax^i»Bific«.tMTui, 



aie so looady conneotad with the floor of the skull, t 
the jaws can be protruded and retracted to a coasiden 
exteot. 

In Lepidoiteag, Folyplenis, and Amio, the skull pi 
not only membrane bonea, but, in addition, basi-oceipii 
ex-occipital, and pro-otic osaifieationa of the primordial 
lage. to which others may be added. The vomers ; 
aa in the Amjihibia (P Polypterus). The apparatus of 
jaws has become mudified in accordance with the Tt" 
tean type of structure. The suapensorium conaietB ot 
ossifications united by a carttlaginoua interiDediate 
tion. The upper — broad, and moveably articulated 
periotic capsule — is the kyomandibular ; the lower, 
the syniplfctic of osseons fiaLes. The cartilaginc 
quadrate arcade is, in pai't, replaced by a series of 
the palatine lies in front, and is connected 
frontal region of the skull; behind it, lie ri 
of the pterygoid, the metapterygoid, the ectopl 
ajid, moat posteriorly, of the quadrate bone. The 
nishea a condyle to the articidar element of the 
The symplectic is either loosely connected with the 
rate, as in Lepidoateue, or more closely united with it, B«!b 
the other genei-a. 

In L^idoutetis and Amia, a stiMUg and long membrKiie 
bone, the prec^erculam, is developed on the outer side fd 
the hyomandibular and quadrate bones, and connectd them 
atill more firmly together. 

The maitilla ia repreaented by a aeries of email eeparatu 
ossifications ia Lepidosteiia. The pi-oiimal end of the 
mandibular cartilage ossifies, and becomes a diafinct flrtt- 
culture. A detiiary element is added on the outer, and 
«pleaial one upon the inner side of the cartilage; and in 
Lqiidosieas, angular, mipra-angular, and cryronary elements 
are added, so that the components of the mandible skk* 
numei'ous as in reptiles. LepidoBtetia and Amia have 
chioBtegalraya, hutPo^KpiertighiLsnone— at any rate, of the 
ordinal^ kind. A single ji'ffu^ar plate is developed between 
i of the mandible in Amia, and there are two suicb 



THE GANOIDEI. l^S 

plates in Polypierusy which may possibly represent branchio- 
siegal rays. 

In Accvpenser, Spatularia, and Amia, the pectoral arch 
presents two constituents : one, internal and cartilaginous, 
answers to the cartilaginous pectoral arch of the Elasmo- 
hranchii, and to the scapula and coracoid of the higher 
Vertehraia ; the other, external, consists of membrane bones 
representing the clavicular, supra-clavicular, and post- 
clavicular bones of the Teleostei. In Lepidostevs one centre 
of ossification appears in the cartilage; in Folypterua, 
two. The upper represents the scapula, and the lower the 
coracoid. 

It has been already stated (p. 39) that Polypterus comes 
nearest to the Elasmohranchii in the structure of the rest 
of the limb. The numerous dermal fin -rays, all nearly 
equal in size, are connected with the rounded periphery of 
the broad and elongated disc formed by the skeleton of the 
fin ; and the scaly integument is continued to the bases of 
the fin-rays, which thus seem to fringe a lobe of the integu- 
ment. Hence the fin is said to be lohate. In the other genera, 
only two of the basal cartilages are present, and some of the 
radialia come into contact with the shoulder-girdle between 
them. In addition, the anterior dermal fin-ray is much 
larger than the others, and becomes directly connected with 
the anterior basal cartilage. Thus, in the structure of their 
fins, as in so many other characters, the Gunoidei ai'e inter- 
mediate between the JElasmobranchii and the Teleostei. 

In certain Ganoids, as LepidosteuSy Accipenser, and many 
fossil genera, the anterior margins of the anterior fin-rays 
of the dorsal fins, bear a single or a double series of small 
scales, or spines, caJledfuUsra, 

In Acdpenser and Polypierusy spiraculay or openings which 
communicate with the mouth, lie on the top of the head, in 
front of the suspensorium, as in many Elasmobranchs. 

LepidosteuSy Acdpenser ^ and Scapirhynchusy have branchiae 
attached to the hyoidean arch, as in the ElasmohranchiL 
They are now called opercular gills. 

In Polt/!pte9iis the air-bladder is do\i\)\e aaa.^ ^^^acviX^X-^^, 



144 THE AN4T0MY OP TEBTEBKATED ANIMALS. 

and the pneumatic duct opene upon the ventral aspect of 
the tesophagua. The air-bladder thus becomes exceedinglj 
like a lung; but its vessels ore in communication with 
tl]i>ae of the adjacent parts of tie body— not with the heart, 
us in a trua lung. 

In L^idoeleite, the ducts of the male and female repro- 
ductive organs are continuous with those bodies, and eaok 
duet opens into the dilated uret«r of its side. In the otiter 
Fig- 43. 




Fi}!. ■12.— The femnle rpproduciii 
npen ends of (he penital duels 
left divlBione of tlie urinary 1 

nreters into tbe blaililer;/, the bdus; p, g, the abdominal porn; 
A. Ibe urogenital apeTture. 

Uanoids the proximal ends of the genital ducts, inboth aexn, 
open widely into the abdominal cavity. In Pohgatonu the 
united uretei's open into the cavity of the oonflnenl ori- 
ducts. whUe, in the other Qanotds, the oviducts op«i into tte 
dilated ureters. (Fig. 42.} 



146 J 

Tien the fossil, a^ well as the eiisting Ganoidei, a 
u into account, thej form a, large order, divisible j 
} the following suborders ; — 1. Aniad<e, 2. LepiAoaleidis, ] 
iroaecplerygidiE, 4. Clumdroateidce, all of which have living 1 
reaentatives; whiletheotherthree— viz.,5. CephalaapidCB, ! 
Vlaeodermi, and 7. AcardhodidcB — have been eitinct Binoe 
I Palwozoic epoch, and ai'o only ranged among the Gaaoida 
tvisionallj', inasmuch as we have no knowledge of their | 

il anatomj. 
. The Amiadm have a single living representative in 

s of North America — Ainia calva ; and it is not certain | 
it any member of the group occurs in the foasil Btat«. 1 
cycloid Bca.le3, preoperculum, single median jugular I 
g, branchiostegal rays, non-lobate paired fins, and 
terocercal tail, diagnose the suborder. 
IL Hhe ■ Ly>idasteid(B have rhomboidal enamelled acales, 
preopercnlnm, brajichiostegal rays, non-lobate paired I 
, and heterocercal tail. These are represented in 
iTB of North America at the pi-esent day, and in tertiary 1 
s, by Lepidostitus ; in the Moaozoic rocks, by a great I 
detyof genera — Lepidotas,(Ech7nodus,Dapediiis, Sx-i and, | 
the Palffiozoic epoch, by Paieffnwcws in the Carboniferous, 
3 probably by CkeirolepiB, in the Devonian, formation. 
1. In the CrOBBopt^gidtB the scales vaiy in thickness and j 
a and may be thin and cycloid or thick and :j 

F g «3 B«» B not Hoi p eh m 




aboid. The dorsal fins are either two in number, o: 
le, very long, or mtiltifid. The pectoral fins, and usually I 
~ I, »xe lobote ; they ar<^ sonietimes rounded, a 



146 THE ANATOMY OF VEETEBttATED J 



iaPolyiyttrms — sometimes greatly elongated and almost fili- 
form, as in Holoptychim (Fig. 43). TUero are no branchio- 
stegal raya, but two pi-iucipal, and somctimea many amaller 
lateral, jngular plates. The tail may be either diphye«realor 
beterocercal. 

The only living representatives of this suborder are 
Polypteriia and CalwmoicMhys, which inhabit the rivers o( 
North Africa. Neither of these are known to occur in the 
fossil state. The only family of the suboi-der at present 
known among Mesozoic fossils is that of the dsIaoaiUkini, 
a remarkable group of fishes with a pei'sistent notochord. 
rudimentary ribs, an air-bladder with ossified walls, and a 
single interspinoUH bone for ea:Ch of the two dorsal fins. 
The Ctelaeantkini also occur in the Carboniferous formSr 
tion; and tie great majority of the Crogsoplerygitke are 
found in tliis and the Devonian formations [(hteole^. 
Hiplopterae, Glyptoliemms, MegalichthyB, Holoplyckiv», Bhi- 
zodvM, TH-pterns, Phaneropleuron, jLC.). Megalieklhyg, IH- 
ptents, and probably a few other of these fishes, have partially 
ossified veitobral centra; the i-est possessed a persiBtent 
notochord. It ia by the Croesopierygid/E that the Ganoids 
are especially connected with the IHpiioi, and, through 
them, with tie Amphibia, 

4. The Ckondroiteiilee are either naked, or have dermal 
plates of bone in the place of HOalea. Neither the pectoral 
nor the ventral fina are lobate. The branehioategal rays 
iire few or absent, the tail is beterocercal. There are no 
cartilage bonea in the bi'ain-case. The teeth are very smaU, 
ur abseiLt. 

The Sturgeons [Accipetiter] — which inhabit the nortlieni 
rivers of Europe, Asia, and America, occasionally migtatuig 
to the aea — Spatularia, aai ScapirhyTichna (found in the rive™ 
of North America), ai-e the recent members of this gronp, 
which is represented, in the older Mesozoic rocks, by Chon- 
d/rontejis, 

6. The C^halaspidaa are remarkable fishes, prubuhly 
allied to the ClKindroiteiiliB. which occur only in the Lower 
Devonian and the Upper Silurian rocks, and are aotau vt 



THE GANOIDEI. 147 

the oldest fisli at present known. The head is covered by 
a continnous shield, which has the structure of true bone, 
in C&phalaspis, but more resembles certain piscine scales, 
in Pterajpsis. The shield is prolonged into two horns 
at its posterolateral angles, and a median dorsal back- 
ward prolongation usually bears a spine, in CephdUispis ; 
the body is covered with flat bony scales or plates, and 
possesses two large pectoral fins. The characters of the 
body and fins of Pterapsis are unknown. Notwithstand- 
ing the excellent preservation of many of the specimens of 
these fishes, they have, as yet, yielded no evidence of jaws 
or teeth. Should jaws be absent, the Cephalaspidce would 
approach the Marsvpobranchii more nearly than any of 
the other amphirhine fishes do. 

6. The Placodermi, comprising the genera Coccosteiis, 
Pterichthys, Asterolepis, and some others, are known to occur 
only in the Devonian and Carboniferous formations. In 
these fishes the pectoral region of the body is incased in 
great bony plates, which, like those of the skull, are orna- 
mented with dots of enamel. The caudal region was covered 
with small scales in Pterichthys, while in Coccostetis it appears 
to have been naked. The pectoral member of Pterichthys is 
exceedingly long, covered with suturally-united bony plates, 
and united with the thoracic plates by a regular joint. In 
Coceasteus the pectoral member seems to have had the ordi- 
nary construction. The bones of the head and thorax of 
06cco8^efi« nearly resemble those of certain Siluroid fishes 
(e.g. CloHas) in their form and arrangement, and it seems 
probable that the Placodermi were annectent forms between 
the physostome Teleostei and the Ganoidei, 

7. The AcanthodidcB, on the other hand, seem to have 
connected the Gkmoidei with the JElasmohranchii. The scales 
of these fishes of the Devonian and Carboniferous formations 
are very small, and similar to shagreen ; spines, resembling 
the dermal defences of the Elasmohranchiiy are placed in 
front of more, or fewer, of the median and of the paired 
fins. The skull appears to have been unossified, and the 
pectoral arch seems to have consisted of a single bony hoop. 



148 THE ANATOMY OF VEBTEBKATED ANIMALS. ■ 

Tlie Fy<ModoniidiF, v/hiah. are commoiily groaped among 
the &aiioide, are fishes with much-compressed bodies, like the 
John Dory or the Filefishes, covered with lurge rhomboidal 
enamelled acalea, from which bony ridges projected inter- 
nally, and were imbedded in the integnmeot. The noto- 
chord is peraistent, but the neural arehea and tte ribs 
are ossified. Theproiimal ends of the riba, imbedded in the 
aheath of the notochord, are bnt little expanded in the more 
aocient membera of the gi-oup, while, in the more modern 
speciea, they enlarge, and at length unite by aerrated sn- 
tnres, giving riae to spurious Tertebne. The skull is high 
and narrow, as in BaUnles; the preinaxills are small, and 
there are no teeth in the niaiills, bnt aeveral longitudinal 
series of crushing teeth (the vomer and paraaphenoid ?) 
are attached to the baae of the akull. Theae biba between 
the rami of the mandible, which ai* also armed witli aeveral 
rowB of similar teeth. The teeth of the Pycnodonts have no 
veitical successors. The pectoral fina are small, the ventral, 
obaolete. The Pycnodonta are all extinct, but existed. 
formerly, for a very long period of time — their foaail remains 
occurring in rocka from the Carboniferous to the (dder 
Tertiary formationa, incluaively. They present corioiu 
features of reaemblance to the plectognath Teleoelei. 

The remains of Ganoid fishes began to appear in the 
Upper Silurian i-ocka at the same time aa those of tbe.£^bu- 
taobranehii, with which they constitute the oldest T»te- 
brate Fauna ; they abound in the Devonian formation, and 
constitute, with the Elasmobranehii, the whole of the Pabw- 
zoic Fish Fauna. We are in ignorance of the true affinitiea 
of TharsU and Tliriestyps, and of the Sophpleuridat ; bot 
unless some, or all, of these are Teleosteana, Ganoida and 
Elasmobranchs, alone, constitute the Fish Fauna of tlie 
Uesozoic formations, as far aa the bottom of the Cre- 
taceona aeries. 

V, The TELEoaTEi. — -The oaseous fishes are occasionallj 
devoid of any exoskeleton. Sometimes they present HCiat- 
tered dermal plates of true bone ; or, as in 



THE TELEOSTEI. 

\Ostracion), the body may be incased in a, complete c 
n-htcli iscalcified, but ha^ not the etnicture of boni!. Agaiivl 
as in the Filefisbes [Balistes). the akin may be beset v ' ~ 
innumerable Bmall epines, somewhat like thoae wbiuh for 
i.1ie ehagreen of the Elasmobrancbs in appearance, thougl^'l 
they differ from them in. structure. But, uBuoUy. the 
akeleton of the Teleoateans takes the form of overlapping 
acales, which rarely exhibit the lacuna eharaeteriatic of tinje 
bone. The free portions of the BCalea are sometimes smooth, 
and rounded at the edge, when they are termed cycloid ; or 
they are roughened with ridges and minute spines, whes 
Irliey are called ctenoid. 

The Bpinal column always presents ossified rertebra 
centra, and the primordiul cartilage of tbo akuU is mor^ 
or leaa i-eplaced by bone. Tbe centra of the vertebrte axen 
usually biooncave, each face presenting a deep cunicat'T 
liollow. In certain Ecla {Symbranckiu), the centra of moEit<1 
of the vertebrae are tiat in front and concave behind, the | 
most anterior poaaeasing a convexity in front, In many 1 
Silnroid lishes a certain number of the antei-ior vertebrw I 
are ankylosed together, and with the skull, int<) c 
as in the Ganoids. 

The vertebne are diatingnishablc only into thoae of the 
trunk and thoae of the tail. The latter are provided with 
complete inferior arches, traversed by the caudal artery 
and vein. The former usually possess ribs, but these do 
not unite with one another, nor with any sternum, in the 
ventral median line, imd they enclose the thoracico-ohdomi- 
nal viscera. The vertebrie ai'e commonly united by zjgfcj 
pophyses, or obUquc processea, placed above the centra ; iltfl 
I addition to which, the lower margins of the centiu ar^9 
^HBot nnfrequently, nnited by additional articular processeAfl 
^^mtftaiMrene processes commonly exist, but the ribs are articii- 9 
^Hped with the bodies of the vertebrm, or with the bases otiM 
^^Pie transverBe processes, not with their extremities. J 

I When a doraal fin exists in the trunk, its ruys are articu- 

lated with, and supported by, elongated and pointed bones 
— lh« inlerepinoMi bones, which are developed around pra- 



150 I 

existing cartilages, and lie between, and are connected with, 
the spines of the vertebne. The fin-rays maj be entire 
and ooraplotely oaeified, or they may be trausvei'sely jointed 
and longitudinally subdivided at their eitremitieB. 
unfreqnently, tbe articulation between the fin-rays and the 
interspinoiiB bone is effected by the interlocking of two 
rings — one belonging to the base of the fin-raj and it« 
included dermal curtilage, and the other to the eummit of 
the interapinons bone — lite the adjacent links of a chain. 

In all Teleostean fishes the eitremity of the spinal 
uolumn bcnde up, and a far gi'eater number of the caudal 
fin-iftys lie below than above it. These fishes are, therefore, 
stiicUy speaking, heterocercal. Nevertheless, in the great 
majority of them (as hits been already mentioned, p. 16), the 
tail seems, npon'a superficial view, to be symmetrical, the 
spinal column appearing to terminate in the centre of a 
wedge-shaped hypural bone, to the free edges of which the 
caudal iin-rays are attached, so as to form an upper and a 
lower lobe, which, are equal, or Bubequal. This characteris- 
tically Teleostean stmcture of the tail-fin has Ijeen termed 
homocei-cai — a name which may be retained, though it 
originated in a misconception of the relation of thia struc- 
ture to the heterocercal condition. 

In no Teleostean fiah is the bent-up teimination of the 
notochord replaced by vertebra;. Sometimes, as in the 
Salmon (Fig. 6, p. 17), it becomes eneheathed in caiiiloge. 
and persists throughout life. But, moi-e usually, its sheath 
becomes calcified, and the nrostyle thus formed coalesces 
with the dorsal edge of the upper part ot the wedge-shaped 
hypuTiJ. bone, formed by the ankylosis of a series of ossieles, 
which are developed in connection with the ventral face of 
the sheath of the notochord. 

In the caudal region of the body, interspinous bones arc 
developed between the spines of the inferior ai-chea of the 
verte'(>rai, and bear the fin-rays of the anal and, in part, of 
the caudal fin. 

The TeUoglei differ very much in the ejctent to which tlie 
primordiiil cranium persists throughout life. Bometimea, j 



THE TBLEOHTEI. ISti] 

1. the Pike (f iga. 44 & 45), it grows with the gi-owth of 
e flah, and only becomes partially ossified ; in 
I alnioat disappears. A baai- occipital (B.O.). es-oceipital 
E.O.), and supi-a- occipital [8.0.) hone arc developed i 




1 

Df 



OF VERTEBRA.TED ARIlt 



times ai-e and sometimes are not developed. 
Fig, 45. 





THE TELEOSTEl. 

read tt^g.c.^ anterior^ HDd p.B.c,, poetarior flemif^irc 
parasphecoid ; ^, Ihc bodisphenoid ; Fo, tiiu vonie 

Bphenoidal and orbitoaphenoidal r^ous commonJj, but- 
not alwajs, i-emain unoBBified. 

In most oBseuus fishes, the haae of the Bkull in front of 
the baeispheaoid is greHtlj compressed from side to Bide, 
und forms an iaterorbital septum {I. Or.). The anterior 
moiety of the craniaJ fiavity ia consequently reduced to a 
comparatively mirj-ow pasBuge above the septum (Fig, 45). 
In the SUuroid and Cyprinoid fishes, however, this aeptnm 
is not formed, ajid the cranial cavity is of nearly equal si26 
throiighont, or gradually diminishes forwardB, The ethmoidal 
cartilage usually remains unoseified, but sometimeB, as in 
the Pike, ossification may take place in it. (Fig. M, 3, 3.) The 
antorbital, or lateral ethmoidal, processes of the primordial 
cranium ossify, and give rise to the pi-efrontaJ bones {Pr/.). 
The postorbital processes also ossify aa postfrontalB 
{Ptf.). The upper and posterior part of the primordial 
cranium exhibits five processes — one postero -median, two) 
postero-lateral, and two postero-extemal. The postero-{ 
median ossifies as part of the supra- occipital [8.0.) The 
postero-lateral ossifies as part of the epiotio {Ep.O.), which 
lies upon the suoimit of the superior vertical semicircular 
canal. Tbe postero-eiternal closely corresponds with the 
aqniUDOsal of the higher Vertebrata in position ; but, aa a 
Cartilaige bone, it corresponds with an ossification of the 
capsule of the ear, called pteroUc in the higher Vertebraia, 
Not unfvequently, as in the Cod, for example, the opisthotic 
lOp.O.) is a distinct bone, and enters into the formation of > 
tbe poatero-extemal pi'ocess. The pro-otic (Fr.O.) is alwaye 
a well -developed bone, and occupies its regular place. iiT 
front of the anterior vertical semicircular canal, and behind 
tbe exit of the ti-igeminal nerve. 

In addition to these cartilage bones, the brain-case of 
__9Meou8 fishes is additionally defended by numerous mem- 
e bones. These are, on the roof of the skull — 
, ,T1>£ parietal bones (Fa.), which aometimes meet 



I 



I 154 THE AKATOMY 

Kflagittol Buture, as in moet of the liighH' Vefi 
Tvei^ generally aeparated bjthejuiictionof th^ 
Kthe suprai-occipital. 

2. The large frontals (Fr.), which may o 
|jmto one. 

3, The naaal bonea (Na.), apparently replace* 
■ ty the bonea 1 and 2. 



156 THE ANATOMY OP VBETEBRATED ANIMALS, 



TLe palato- quadrate and Ljomandibular have essentiBlly 
the. same stnicture and an-angement as in Leptdoeieite 
and Amia, The boinolugue; of the suspenBorium of the 
Elastnobranckii ia artii;ulated witli a surface fumialied to it 
by the postfronta], pterotic, and pro-otic bones. UanaUj it 
moves freely upon that aurfaee, but, in the PUdoynathi, it 
may be fixed. It oasifies ao aa to give riee to two bonee : an 
upper broadft.jo)jwnwfi(nttariff.4r.). with which the operculum 
articnlatea; and a lower styliform aympleetie [By.), which 
fita into a groove on the inner and posterior surface of the 
quadrate, and ia firmly held there. 

The palato.quadrate arch is represented hy several 
bones, of which the most conatant are the palatine \Pl.\ 
in front, and the quadrate (Qu.) behind and below. BeaiJea 
these there may be three others ; an external, ecti^lerygoid 
[Ecpt), an interna], enlopierygoid (Ept), and a metaptenj- 
goid {Mpt,), The laat envelopes the upper and poaterior 
portion of the pi'imitive quadrate cartilage ; and, fixing 
itaelf againat the hyomandibular, contributes to the firm- 
nesa of the union already efiected by the symplectic. 

Meckel'a cartilage [Mck.] persists throughout life, but the 
ossification of its proximal end gives rise to an os artietdare 
in the lower jaw. To theae an angular (.An.) and a dentary 
(D.) membrane bone are commonly added (Fig, 47). 

The hyoidean arch ia usually composed of two targe 
comua— connected with the cartilaginous interval between 
the hyomandibular and the symplectic by a ttylokyal ossi- 
fication, and abutting, in the middle line below, upon one or 
more median pieces, the anterior of which {mUoglotsat} sup- 
ports the tongue, while the posterior ^urohyal) extends ba«k 
to join the median elements of the branchial apparatus. 
The cornua themselvea are usually ossified into fonr pieces ; 
an upper (epihyal) and a lower iceratohyal) large ossification, 
and two small ones {basihyalt) connected with the ventral 
ends of the lower large ossification. 

There ai-e usually five pair of branchial arches connected 
by median ventral ossifications. The poaterior pair are 
single bones, which underlie the-flixir of the pharjnx, bear 




THE IKLEOSIEI. 157 J 

■Itu branchial filomentB, but commonly support teeUi, anS' 
■e called hypopli/infngeal bonca. In certain osseous fiehe^ 
(hence culled Pharyngognathi, tliej anijloae together istO' 

e bone. Tbe anterior four pair are composed of sevend 
KlntH, and the uppermost articulatione of more or fewer 

leually expand, bcarteeth.andform theepip/tarynifsal 
bonee. Sundiy important membrane bones are connected 
with the mandibular and byoidean urches. The preoper- 
tulitm {F.Op.), operculmm [Op.), and branchiogtegal raja (Br. j, 
already met witb among the QaTiaidm, are the moat constant 
of these. Beneath the operculum, lies a mibopercitlmn(8 " 
and below thia an interoperiralum il.Op.), which is 
nected by ligament with the angular piece of the lower jaw, 
and is also united to the out^r face of the hyoidean arch, 
may be altogether ligamentous, as in the Siluroids. 

The branchiostegal rays are attached partly to 
and partly to the outer, snrface of the hyoidean arch. Thej 
support a membrane, the bra/nchiostegal ineinbrane, wiiicl 
serves as a sort of inner gill- cover. 

Most Teieoutei pOBseas two pair of limbs, the pectoral 
the ventral fins. But the latter are often absent, and the 
former ore occasionally wanting. When the pectoral fins 
are absent, the pectoral arch naunily remains, though it 
maybe reduced to little more than a filament, as inJtfi(rml> 
ophU. The ventral fins are frequently situated in their n( 
mal position beneath the posterior part of the trunk; hut 
considerable groups of those fishes they are immediatt 
j><behind the pectoral fins {thoracic), or even in front of theaB< 
In the asymmetrical FiearoneetidtE one pectoral 
[n may be larger than the other, or nlay iJone remain, ea 
& SEonoekirus. 

f 'The pectoral arch always consists of a primarily cartila* 

jscapalar portion — which usually ossifies in twa 

8, a coracoid below, and a scapula above — and of aundiy 

mbiune bones. The chief of these membiune bones iB 

t davicula {CI. ), which meets its fellow in the middle lin^: 

^<ji«0al^ joined to it by ligument, but sometimes. 




158 



THE ANATOMY OP VERTEBRATED ANIMALS. 



in tlie Siluroids, by sutural union. By its inner surface it 
gives attachment to the coraco-scapular — and sometimes 
above them, to a stylif orm bone which extends back among 
the lateral muscles — the post-clavicula (p.cl.). 

Attached to the dorsal end of the clavicle, there is 
usuaUy a second much smaller bone, the supra-ckivicnla 

Fig. 49. 




Fig. 49.— The bones of the pectoral arch and fore -limb of the Pike 
{Esox lucius). A, a semi-diagrommatic view of these bones, to 
show their relative natural position. The clavicle ( CI) is supposed 
to be transparent. S.cl^ supra-clavicula ; p.cl, post-clavicula ; c, «/, 
the posterior and anterior ends of the outer margin of the scapulo- 
coracoid. — B, the scapulo-coracoid and limb separate and on a larger 
scale ; Sep, scapula ; O, coracoid ; a, basal cartilages ; b, fin-rays ; 
c corresponds with c in the foregoing figure. 

(S.elX and this is very generally connected with the skull 

^j^ a suporhcial membrane bone, the post-temporal, which, 

j'n front, becomes forked, and attaclnea itseVi \i^ o\ie ^^oxi^ 



THE TELEOSTEI. 159 

to the epiotic bone, by the other to the pterotic, or lower 
down to the side of the cranium. The base of the fin 
contains a series of not more than five, more or less ossi- 
fied, cartilages, which are placed side by side and articn- 
late with the coraco-scapular ; to these succeed one or more 
rows of small cartilages, paiiiially hidden by the bases 
of the exoskeletal fin-rays. The most anterior of these 
basal cartilages (the mesopterygial basale) is inclosed by 
the base of the anterior fin-ray, and effects that articula- 
tion with the shoulder-girdle which is so remarkable in 
many Siluroid fishes. The posterior cartilage, or bone, is 
the metapterygial basale, and the intermediate three are 
radialia (p. 40). 

Most Teleostei possess teeth, and, in the majority of these 
fishes, teeth are very widely distributed over the surface of 
the walls of the oral and pharyngeal cavities. The teeth 
vary very much in structure; ordinaiily, they consist of 
dentine, capped with structureless enamel. The parietes 
of the tooth are not unfrequently longitudinally folded 
towards the base, but this folding never goes so far as in 
the Ganoids. The different kinds and modes of arrange- 
ment of the teeth may be classified as follows : — 

1. Isolated, more or less pointed teeth, developed from 
papillae of the mucous membrane, which do not become in- 
closed in sacs — ^frequently ankylosed to the subjacent bone, 
but not imbedded in alveoli, nor replaced vertically. 

The great majority of ordinary osseous fishes have teeth 
of this kind. 

2. Isolated teeth, which become imbedded in sockets, and 
are replaced vertically. 

Such teeth are seen in the premaxillse of Sargiis, where 
they curiously simulate the form of human incisors ; and, 
imbedded in the coalesced hjrpopharyngeal bones, in Labrus. 

3. Isolated teeth, imbedded in the substance of the bone 
which supports them. The teeth and the suppoi-ting bone 
wear away in front, and are replaced by new teeth developed 
behind the others. This stinicture is Reea. Vn \\ifc oa^J^^'aRfe'^ 
hypophaijngeal bones of the Parrot^aVi i^Sconrua^, 



4. Beak-like compound teeth, attiiched to the premaxillEe 
and dentary bones of the mandible. 

These are of two kinds. In the ParrotfiBh (Seams) the 
beak is formed by the union of numerous separately de- 
veloped teetb into one maas. But in the Gymnodonte 
{Tetrodoa and Biodon) the beak ia produced by the coalea- 
cence of bi'oad calcified horizontal lamelUe thrown off from 
a subjacent pulp, 

5. In the Cai-p and its allies the basi- occipital eenda down 
a median pi-ocess, which expands at the end, and supports a 
broad, thick, horny tooth. 

Tlie stomach ia usually wide and sac-like, but sometimes 
(in Scoiiibereeoceg, Cyprinoidg, and others) is not wider than 
the intestine. Occaaionully, as in Mug^il, it acqairee thick 
walls and becomes gizzard-like. The commencement of 
the small intestine is verygeneraUyniarked by the presence 
of more or lesa numerous ciecal diverticula, thepyloric aeoa. 
The small intestine hae no spiral valve, though the mucous 
membrane may be raiaed into large tranaverHe folds. The 
rectum docs not terminate in a cloaca, and almost always 
opens quite separately from the uiinary and genital ducts, 
and in front of thetu. 

In many Teleostean fishes an air-bladder underlies the 
vertebral column, and ia connected by an open pneumatic 
duct witli the dorsal wall of the (Esophagus, or even with 
the stomach, as in the Heiiing. In other T^odei, the air- 
bladder occupies tie aame position, but is closed, the dnct 
by which the air-bladder is primitively connected with the 
alimentary canal becoming obliterated. In a comparatively 
amaU number of the Tekoetei — the Blen/aii, the PlewoneC' 
tidiE or Flatfishes, the Sand-eel (Ammodyten), the Loriearini, 
and Synibranchii, and some members of other families — 
there ia no air-bladder. In tiioae Teletmlei in which it is 
present, it may be divided into two parts by a, constiiction; 
or it may be prolonged into diverticula; or reiia mirabilia 
may be developed in its walla. Sometimes the air-bladder 
ia brought into direct relation with the membranous laby- 
rinth, as in Myriprietix and Sjiiiriis, and the Herring, Shad, 



^■sjid Anchovy— prolongationa of the oue organ being s( 
^^Tated from the other only by a membranous fenestra ii 

vhII of the akull. In the Silmroidei, Cyprinoidei, and CAsiu 
1-aei.ni, and in the Gynmotitd. the anterior end of the M(9 
bladder is conneeted with the membranous vestibule by (J 

intermediation of a aeries of bonea attached to the rertebra 

column, some of which are moveable. 

Tho voBselH of the air-bladder are deiived from, and emptW 
themselvee into, thuee of the adjacent parts of the body, i 
■which respect, and in the dorsal position of the (BSophaj 
apertare of the pneumatic duct, this atrncture differs fi 
ft lung. 

The heart consiBts of a single auricle, receiving its blood 
ttroia a venous sinus ; and of a single ventricle, separated by 
K single row of valves from the iiwHitts iiorto, which is not 
ThythmicaUy contractile. 

The cardiac aorta divides into trunks to form the branehial 
.arteries, which run upon the outer, or uonvex, side of the 
brsncbial arches, anil are distributeil to the branchial fila- 
jnents. The blood is millected thence into a branchial 

in, which also lies on the oonvei side of the arch; and. 
increasing towards its dorsal end, opens into one of the 
trnnks of the oi'tginal dorsal aorta. Of these there are 
I right and a left, which pass backwards and meet in 
"trunk of the dorsal aorta under the spinal column. 

The anterior branchial vein gives off, at its dorsal 

ination. a considei^ble carotid trunk, which passes for- 
wards under the base of the skull; and this is united with 
Ita fellow by a transverse branch — so that a complete arterial 
Dircle, the ei/rculus eephalieaa. w formed beneath the base of 
the skull. Below, the anterior branchial vein gives off the 
byoidean artery, which ascends along the byoidean arch, 
and very generally terminates by one branch in the cephalic 
■circle, and by another enters a rete miroMle, which lies 
in the inner aide of the hyomandibular boie, and some- 
times has the form of a giil. This is the pseadobranchia. 
The branches of the rete mirabile unite again into tht 



iiphtlialuuc artery, which pierces the eclerotic. and breaks 
lip into another rete mirabUe, the elioroid gland, befoi-e beinK 
(iuaUy distributed. 

In the Lumpvej, as has been Been, the respiratory orgvis 
iirc- ponchea, the anterior and posterior wbUb of which are 
raised into vascular folds. The walla of adjacent pouches 
are distinct and but loosely connected together; and con- 
siderable spaces of integument aapaj'ate their rounded outer 
Hpertitres. 

In the ordinaiy Elusmobrant:hii, the bi-auchial pouches 
Jive more flattened trom. before backwards, and their outer ■ 
apertui'es are more shtUke. The integumentary spaces 
Iwtween the slits are correspondingly nan-ower, and the 
adjacent walls of successive pouches are more closely ap- 
proximated, so tiiat they are divided only by septa; but 
the vascular plaits of the surface of the respiratory mauous 
membrane do not reach the outer edges of these septa. 

In Ckifnmra, the free edges of the septa ai-e exceedingly 
nai-row, and the apices of the branchial processes extend 
outwards to them. 

In the Sturgeon, the sejitum. is not more than three-fourths 
iiB long as the branchial processes, the apices of which are 
consequently free, 

Tlie process of reduction ia carried still further in the 
Tdeostei — the septum not attaining to more thim one-thii'd 
tlie length of the branchial processes ; and, as in the 
Gianoids, each process is supported by an osseous or cartila- 
ginous skeleton. 

The Telaoatei have no functional hyoidean, or opercular, 
gill ; and, aa a genei-al rule, each of their four branchial 
arches possesses a double aeries of branchial pi'ucesses, 
making eight in all. Not unf requently ( Coihts, Cyehyptemn. 
Zeut. &c.), the number is reduced to seven ; the fomth bran- 
chial arch having only one series, the anterior. In this 
case, the gill-cleft, which should lie between this arch and 
tbe fifth, is closed. Sometimes thei-e are only six series of 
branchial processes, the fourth aivh l)eiuy devoid of any 



THE TBLEOSTEI. 

(e.g., Lophiug, Diodon). In MoMhasa the miDiliei' ia reduci 
to five, only the anterior series of the third ari:h beingf^ 
fleveloped ; snd in Annphipaoim euehia only the second braii*- 
rohial ai-ch puaseases branchial filaments, the first, 
isd fonrth heing devoid of them. 

Many Teleoatean fiahea poBBeaa accessory respiratory 
)rgBDB. These may take the form of arhorescent appendages 
10 the upper enda of some of tae branchial archea, as in 
[JIaftoji, Melm-ohranehus. and Hderotis; or, aa in the Climb- 
^ Ferok (Anabas) and its allies, the epiphai-ynffealhouea 
nay enlarge and acquire a lahyrintMc honeycombed 
itructwre, and support a large surface of vaacnlar muoou«j 

Ls in the Clupeoid :l>!rfoiieira chanoe), 
ioceaaory gill may be developed in a curved ci 
icm of the branchial cavity. Finally, in Saccobranckus 
iagio and in Ampliipnous cuchia, the membrane lining the 
iranchial chamber ia prolonged into saca. which lie at the 
ides of the body, and receive the blood from the diviaiona 
t the oardiac aorta which supply the branchise, whiie they 
etnm it into the dorsal aorta. 

All these fishea (except Lntodeira) are remarkable tot. 
iieir power of suataining life out of the water. Many in^' 
labit the marahea of hot countries, which becom.e 
eaa desiccated in the dry aeiison. 

The tidneys of Teleoatean fishea receive a great part of ij 
lieir blood from the caudal vein, which ramifiea iu them. .T 
!hey vary greatly in length, scimetimea extending along,! 
be whole nnder-aurface of the vertebra! column, fi'Oi 
ead to the termination of the abdomen. TUe uretare pas* 1 
ito an urinary bladder which opens behind the rectiim. 
The brain in the Tehostei has solid cerebiul hemisphere 
and, when viewed from above, the thalameiicephalon is 
hidden bytheapproiiniationtothe bemiaphereaof the large 
and hollow optic lobes of the meaeaeophaloa, which haa a 
inferior enlargements, lobi in/erioret 
ity about the atructure of the optic lobes, which b 
je to much diversity of interpretatio) 



4 



164 THE ANATOMY OP VEaiBBBATED ANIS 

of the brain in osseoua fishes. The poaterioi' wall of these 
lobea, where it passe s into the cerebelluni, or in the 
region which nearly answers to the Talve of Tieusaens in 
mammals, ia thrown forwards into a deep fold which lies 
above the crura cerebri, and divides the iter a tertio ad 
qmxrtmn ventricvlum from the ventricle of the optic lobes 
throughout abnoat the whole extent of the latter. This fold 
is the " fomii " of Gottsche. On each aide of it the floor 



Fig. 50, 



;. SO.-Bniin of 




of the ventricle of the optic tobes is raised up into one or 



inencBB, which have the 
lobea BB the corpora sUriaia have 
veeicle. 

The optic nerves simply cross om 
chiasma. The cerebellum is usually large. 

The cephalic pert of the sympathetic ne 
in the higher Vertebraia. 



relation to the optic 
the proseucepbalic 



another, and form i 



ebe nasal eaas ueuall; upena extemallj bj two- 1 
In some G^mnodoiitB a solid tentacle ie said t<V J 
. ^.^je of a nasal sac. I 

The eyea are sbortiye in the Blind-fish of the caves of "I 
Kentucky iAmblyopsis spekeiw). A fihrous hand often J 
la from the hack of the orbit to the sclerotic, and re- J 
mts the cartilaginous pedicle of the BlaBmobranebftrM 
o nictitating membmiie, bat immoveable eitenial .1 
^elids may he developed. The choroidal gland, mentioned J 
, suiToimda the optic nerve between the aclerotio J 
and the choroid. Very generally, a falciform procegs of thf J 
latter membrane ti-aversea the retina and vitreous humour to I 
the crystallijie lens. This represents the pecten of hipiher ' 
Vertebrata. As in either fishes, the lens is spheroidal, and 
the ooraea flat. The saeculus i>f the auditory orgMi con- 
tains large solid otoliths, which ai-e usually two in number 
—the larger, anterior one, is termed SagiUa : the amaller, 
osteiior, Aeteriscvs. There are always three large semi- J 
X canalH. 1 

L The reproductive organs are either solid glands which J 
it into the abdominal cavity, whence their reprodnctivfJ 
ments are conveyed away by ahdoiainal pores ; or, as is j 
mal, they are hollow organs, and are continued backiJ 
s into ducts which open beside, or behind, the nrinmyJ 
"aperture, I 

Some few Teleostei are ovoviviparona (e.g.. Zoarcee viol- J 
pants), the e^^ being retained in the interior of the ovary, ,1 
and hub^hed there. In the male Syiignatkue, and other- 1 
Wfffipkohrittuikii, integumentary folda of the abdomen grov 1 
^Bown and form a pouch, into which the eggs are received; ,1 
Hnd in which they remain until they are hatched. I 

^K The young of oascuiia Hahea are not known to undergo j 
Buiy nietamorphosia, nor in-e they provided with external I 
Hgdlls. nor with spirocula. I 

H The elasaiiication of the Teleostei isnot yet in a thoroughly "1 
BlUiafactory state, and the following arrangement m<iat ha J 
^BK<ir4ed »s proriaional : — ^J 



1S6 THE ANATOMY OF YEKTEBBATED ANIMAIM. 



1. The Pliysoatomi. — This group contaiiiB the Siliiroidei, 
the Cyprinoidei, the Cliaradni, the Cyprinodfmtes.ihe Solwton- 
idm, the Bcopelini, the EBOeini, the Miyrmyvi, the GiUamai, 
the Cliipddce, the Seteropygii, the Mitrmnaidei, Symbranehii, 
and GymnoUm. The air-bladder is almost always present, 
and, when It exiats, has an open pneumatic duct. The aUn 
ia either naked, or provided with bony pLites, or cycloid 
scales ; the ventral fins, when present, are abdominal in 
position. The fin-raya (except in the pectoral and dorsal 
fina of sundry SUwroidei) are all soft and jointed. The 
inferior pharyngeal bones are alwaya distinct. 

In all other Teleostean flahes the air-hladder ia either 
absent, or devoid of an open pneumatic duct. Hence they 
are termed, collectively, Pliysocliati by Haeckel. 

2. The AiMcantkiai.—Tha body has cycloid or ctenoid 
scales, or is naked. The ventral fine, if present, are jugulaa' 
in position. The fin-rays are all articulated. The inferior 
phaiTngeal bones are distinct. {Opkidini, Gadoidei, Fleuro- 
imctldce.) 

The PleurmiectidcE are the most aberrant of all Teleoatean 
fiahes, on account of the disturbance in the bilateral sym- 
metry of the body, skuU. and fins, to which reference has 
already been made (p. 30). 

3. The Aeaiiih^teri have generally ctenoid scales, thoracic 
or jugular ventral fina, entire fin-rays in aome of the fins, 
ajtd distinct inferior pharyngeal bones. The Percaidei, Cata.. 
jjhraeti, Sp'iroidei, Seutitoidei, Liibyrvnthiei, Mitgilmdei, 2fota- 
eanlhini, 8comb«roidei, Squamipennee, Tamioidei, Gobioidei. 
Bletmioidm, Pedtealati, Theuthyes, and Fiatularee, belong to 
ttiis great group. 

4. The FharyngogTtathi is the name given by Muller to a 
somewhat artificial assemblage of fishes, the only cummun 
characters of which are the ankyloais of the inferior pha- 
langeal bones and the closed pneumatic duct. They have 
cithei- cycloid, or ctenoid, scales. The ventral fins may be 
iibdominal or thoracic. The anterior dorsal and ventiiil 
tin-niya maybe either un jointed, as in the Labroidei, Poiiia- 
eeatridfe, Chrmn-idts j or articulated, as in the SomAeresoeeg. 



THE DIPNOI. 



169 



: The two I'emainmg gi-oupa are very peculiar; but I li 
H I do not aee upon what ground tlieyciin be regarded ft 
ardina] value- 

; 5. The Lopliabynnehii, — The body is tiivei-ed with bony ■ 
The ventral fins are almost always abaent. The | 
•T pharyngeal bones aie distinct. The branchial pro- 
s have a, olava,te form, being larger at the free than at 
B attached ende, and are in this respect nnlike those of | 
Biy other fiahea. [Fegasid^, Synjwot/iidte.) 
L 6. The Pleetognathi. — Tlie body is covered with platea u 

le ventral ims are absent, or represented only ] 
r spines. The inferior pharyngeal bones are distinct. | 
■ B premasilliB and, naually, the hyomandibular, 
)veably united with the sltull — a character of rai 
e among other fishes. [GywirtodontidcE, Ontraciontidie, .1 

The greater number of Teleostei are marine. No Anacan- J 
'., Pleetognalhi, or Lnphobranchii, and only one faniily 1 
of Pharyngognnthi (the ChromidfE), inhabit completely fresh I 
water. Oojnparatively few Aeanthopteri ai'e flnviatile. 
the other hand, by far the greater number of the Pkysoiitoa 
i, either temporally or permanently, freshwater fish. 
If the Leptolepidm {ThrUgops, Leptohpui, ThartU] i 
moida, the Teleostei oiv not known before the Cretaceo 
poch, when both Phymstcmi and Atanihopteri make theii, 

, under forms, som.e of which (e.g.. Ben/icl a 
snerically identical with fish living at the present day. 

[ TI. TheDiPNOi.— The "Mudfishes" of the rivers of the 
it and weat coasts of Africa and of eafitem South America 
B nearly transitional forms between the Pieces and the 

~he eel-like body, covei"ed with overlapping cycloid ■ 

es, tapers to a point at its caudal exti'emity, and ii 
rovided with two pairs of long, ribbon-like, pointed ei 
iremtties, and with a caudal fin, 
\ The spinal column consists of a thick notochord, in 
1 cartilaginous slieath, without any osseous or e 



ginous vertebril centra. The proximal enda of oBaified 
nenral arches, of ribs, and, in the caudal region, of inferior 
LiroheB, are imbedded in the sheath of the notochord. 




'ic. ; 


i2.— Skull o' 


tt^-pid, 


itirt 


nmnaten$!- 


-A, the porieto-froi.tal 1 


B. 


the eupri-o 


rbiU.1; 


C. 


Ihe oaEol ;' 


A th 


V»'rheL*n^ibl«: 


the 


vomerine teeth: E.O.. 


Iheen-occii 


pimi ; 


thahyoid; Br, 


. tbo bn 




ioa legal raj 


■Lii 


, the opercular plil 


the 




,id;y,l 


:he 


pliaryngo-l.i 




llie 


■iidltory ab 




; iV, 


. (he nasDl bi 


IC. 





Fin-raya aupport the median fin. The Bkull. tbe palato- 
•|iiadrate, and euBpensorial appai-atUB. form, as in Chiwiera. 




THE DIPKOI. 

e oontinuonB cartilaginoua Taaaa, into the base of whitdl 

i notochord penetratea, terminating in a point behin 

e pituitary foisa. 
► Ho cartilage bone is developed in the place of the basi" 1 
Bcipital, supra-occipital, basiaphenoid, or presphenoid j S 

d there are only two Buch oaaiflcationB, which repreaeat ~ 
the ei-occipitak {E. 0.) in the aide-walla of the cranium. 
A large jKiraBphenoid (a) underlies the base of the akull. 
Upon its i-oof a great Btngle bone (A), answering to the 

jietals and frontala, extends frum the occipital to the 
moidal regions. In front of thia are two nasal bonea {C)J 



,f>' ■ 



raS" 



pig, S3.— LiiogitudinBl aiiil mrlioal seotio 
E The cflrtilfige ia dotted^ the membrnnoi 
[ shaded with linos. A, B. C, D, E, Ug, as iu 
f x,2.Che{>iiratpheiioid; P.8'. cartilaginoiupn 
1 nntnchoni ; Ati, aiiuation nf BniiltorTchanibai 
" ■«; //., v.. VIII., esits bf optic, 
; a, quBciCBto-mnndihUiarnrUculBtion. 



if the skull ui Ltpidotirt»,.A 
iu the fiteeediiig flguroiJ 



Therg is no alisphonoid, but the fronto-parietal and pars*'4 
aphenoid send procesaea towarda one another, which units n 
in front of the exit of the third liivision of the fifth nerve. !l 
There is no interorbitai septum, and the cuvity of the J 
akull remains of tolerably e^'en. diameter throujjhout. 
front of the exit of the optic nei-vea. however, it ia Ion 
tudinally divided by a membraaouB septum. 
~ The ethmovomerine uartilage is continued to the anteTio]^ J 
mity of the aJrall. It bears teeth, but no diatinc^lj 



170 THE ANATOMY OF VEBTEBEATED ANIMALS. 

A great palato-pterygoid osseous arch (D) extends from 
the middle line along the upper and the under surface of 
the palato-quadrate aijch on each side to near the articular 
surface of the mandible. In the middle of the roof of the 
mouth, divergent, cutting, dentary plates are developed upon 
it. An osseous nodule lies in the articular head of the palato- 
quadrate cartilage, and is continuous with the bone F. 

The mandible presents dentary plates corresponding with 
those of the palate, and biting between the latter. The 
hyoidean arch is attached to the posterior and lower edge 
of the suspensorium — which bears a bony ray representing 
an 6perculum — while the hyoidean arch itself carries a 
single branchiostegal ray (Br, Fig. 52). 

The pectoral arch is composed of a median cartilaginous 
part, with two lateral portions of cartilage, at once separated 
from, and connected with, the median cartilage by bone. 
The bone is separated from the cartilage by a layer of 
connective tissue, and seems to represent the clavicle, while 
the cartilage answers to the coalescent coraco- scapular 
cartilages of other fishes. 

The filiform fin is supported by a many-jointed cai-ti- 
laginous rod, articulated proximally with the coraco-scapular. 
Upon this are disposed fine fin-rays like those of the Elas- 
mobranchs, which support the marginal fringe of the fin. 
The ventral fin has the same structure as the pectoral. 

The intestine possesses a spiral valve, and the rectum 
opens into a cloaca. The lungs have remarkably stiff walls, 
and extend through the greater part of the body, beneath 
the spine. The glottis, opening upon the ventral wall of 
the gullet, places them in communication with the cavity 
of the mouth, into which the nasal sacs open by posterior 
apertures, which lie inside the upper lip and constitute true 
posterior nares. The heart has a small, but distinct, left 
auricle, into which the blood which has been aerated in the 
lungs is returned. In addition to lungs, Lepidodren pos- 
sesses both internal and external gills, but the latter are 
rudimentary in the adult. 
The different species seem to differ in fhe maTnieY m which 



THE DIPNOI. 171 

the primitive aortic arches are metamorphosed : but it may 
be said, generally, that the first has disappeared; the second 
supplies an internal branchia developed upon the hyoidean 
arch ; the third gives off the anterior carotid artery, and 
supplies neither internal nor external branchia ; the f oui-th 
supplies only the first external branchia ; the fifth and sixth 
supply both internal and external branchiae; while the 
seventh is connected only with an internal branchia. The 
pulmonary arteiy seems originally to have been given off 
from an eighth aortic arch. 

It is a remarkable circumstance, that while the Dipnoi 
present, in so many respects, a transition between the piscine 
and the amphibian types of structure, the spinal column 
and the limbs should be not only piscine, but more nearly 
related to those of the most ancient Crossopterygian 
Granoids than to those of any other fishes. 



172 THE ANATOMY OF YBBTEBBATED ANIMALS. 



CHAPTER IV. 

THE CLASS AMPHIBIA. 

The IcHTHYOPSiDA. — Class II. — Amphibia. 

The only clearly diagnostic characters of this class as 
compared with Fishes are the following : — 

1. Amphibia have no fin-rays. 

2. When limbs are present they contain the same skeletal 
elements as those of the higher Vertehrata. 

Certain other structural peculiarities are common to the 
whole of the Amphibia, and are very characteristic of them 
without being diagnostic. Thus : — 

1. The body is usually devoid of any exoskeleton, and 
when scales, or scutes, are present in recent Amphibia, they 
are concealed within the skin (Ccecilia, Ephippifer). In the 
extinct Labyrinthodonta, the dermal armour is confined to 
the ventral region of the body. 

2. The vertebral centra are always represented by bone. 

3. The sacrum rarely consists of more than one vertebra, 
though there are individual exceptions to this rule, as in 
Menopoma. 

4. The suspensorial apparatus of the mandible is con- 
tinuous with the skull, which has two occipital condyles, 
and no completely ossified basi- occipital. 

5. There are no sternal ribs. 

The Amphibia are divisible into the following groups : — 

A. A distinct and often long tail ; the vertebi ee amphicoelous or 
opisthocoelous ; the proximal elements of the tarsus not 
elongated. 
A. Two or four limbs ; no scutes or scales. 

I. Saurobatrachia or Urodela. 
a. External branchiae or giU-c\eiU pemalewt, or disap- 



THE AMPHIBIA. 173 

pearing only in advanced age ; no eyelids ; vertebrae 
ampbicoelous ; carpus and tarsus cartilaginous. 

1. P rote idea. 

h. No branchiae or branchial clefts in the adult; eyelids 
present; carpus and tarsus more or less ossified; 
vertebrae commonly opibtbocoelous. 

2. Salamandridea, 

B. Limbs absent, or all four present. Three large pec- 
toral osseous plates and an armour of small scutes on 
the ventral surface of the body ; vertebrae amphi- 
ccelous ; walls of the teeth more or less folded. 

II. Lahyrinthodonta. 

B. Tail obsolete in the adult. 

A. Limbs absent; numerous minute dermal scutes im- 

bedded in the integument of the serpentiform body. 

III. Gymnophiona. 

B. All four limbs present, and the proximal elements of 

the tarsus much elongated ; the body short, and the 
integument devoid of small scutes, though dermal 
osseous plates are sometimes developed in it. 

IV. Batrachta or Anura. 

The integument in most Amphibia is soft and moist, as in 
the Frog, where numerous glands open upon its surface. 
The Gymnophiona are exceptional, among existing Amphibia, 
in possessing small, rounded, flexible scales, like the cycloid 
scales of fishes, imbedded within the wrinkled integument. 

In certain Batrachia (Ceratophrys dorsata, Ephippifer 
awraniiacm), flat dermal bony plates are developed in the 
dorsal integument, and become united with some of the 
subjacent vertebrae. Many of the extinct Lahyrinthodonta, 
and probably the whole of the members of that group, pos- 
sessed an exoskeleton which appears to have been confined 
to the ventral surface of the body. Under the anterior part, 
of the thorax there is a sort of plastron composed of one 
median and two lateral plates. The median plate is rhom- 
boidal. The lateral ones are somewhat triangular, and unite 
with the anterolateral margins of the median plate by one 
side, sending a process upwards and backwards from their 
outer angles. The outer surfaces of all these plates exhibit 
a sculpture, which radiates from the centra ol >5)afc xcifc^^s^ 
plate and from the outer angles o£t\ie\8A)et«\''^\«a. ^Y>aft.'aft. 



174i THE ANATOMY OF VEBTEBBATED ANIMALS. 

plates are in close relation with tlie pectoral arcli, and 
probably represent the interclavicle and clavicles. 

Minute bony plates cover the surface of the throat in a 
small African Labyrinthodont, Micropholis. I have not met 
with dermal ossicles in this position in other Labyrinth o- 
donts. But in Archegosaurus, Fholidogdster, Urocordylus, 
Keraterpetoviy Ophiderpeton, Ichthyerpeton, the integument be - 
tween the thoracic plates and the pelvis presents regularly- 
disposed rows of small elongated ossicles, which, for the 
most part, converge from without, forwards and inwards, 
towards the middle line. No trace of these appears upon 
the tail, nor in any part of the dorsal region of the body, nor 
on the limbs. 

The endoskeleton of the Amphibia is least complete in 
Archegosaunis, where the centra of the vertebrae are repre- 
sented only by bony rings, the ribs and the neural arches 
being well ossified. In other Labyrinthodonts of the same 
(Carboniferous) epoch, however, such as AnthrcLcosawti^, the 
centra of the vertebrae are completely ossified biconcave 
discs, very like the centra of the vertebrae of Ichthyosaums. 

In the existing Froteidea, and in the Gymnophiona, the 
vertebral centra are amphicoelous. In the Salamandridea 
they are opisthocoelous. In Pipa and Bomhinator they are 
also opisthocoelous, but in other Batrachia they are, for the 
most part, procoelous, but vary in different regions, some 
being biconvex and some biconcave. 

The first vertebra, or atlas, presents two articular cups 
to the condyles of the skull, but there is no specially modi- 
fied axis vertebra. 

The transverse processes may be simple, but in the Laby- 
rinthodonts, and in the existing Salamanders, they are 
divided into two processes — an upper tubercular, and a lower 
capitular^ process. When the transverse process is thus 
divided, the proximal end of the rib is correspondingly split 
into a capitular and a tubercular process. 

In the Gymnophiona, the Saurobatrachia, and the Lahy- 
rlnthodonta, the number of the vertebrae in the trunk is con- 
siderable, and the members of the two latter groups have 



THE AMPHIBIAN SKELETON. 175 

long tails. But in tLe Batrachia, the total number of verte- 
brae does not exceed eleven, of wbicb eigbt belong to tbe pre- 
sacral region, one to the sacrum, and two (modified vertebrae) 
to the coccygeal region. The transverse processes of some of 
the presacral vertebrae are usually very long, but there are 
no separately ossified ribs. The transverse processes of the 
sacral vertebra are very large and expanded, and its centrum 
has usually a single concavity in front and a double convexity 
behind. 

The coccyx consists of a long, cylindroidal, basal bone 
proceeding from the ossification of the sheath of the termi- 
nation of the notochord, and corresponding with the urostyle 
of the Teleostei ; and of two neural arches, which lie over its 
anterior end, and become ankylosed with it. The anterior 
face of the coccyx usually presents two concave facets for 
articulation with the posterior convexities of the sacmm. 

The cavity of the cranium is not narrowed anteriorly by 
the development of an interorbital septum in any Amphi- 
bian. All existing Amphibia have ex-occipitals developed 
in the walls of the cartilaginous cranium; but it is not 
certain that any such ossifications existed vaArchegosaurus, 
though they are present in other Labyiinthodonts. 

No Amphibian possesses a complete basi-occipital, supra- 
occipital, basisphenoid, alisphenoid, or presphenoid car- 
tilage bone. In existing Amphibia, a pro-otic ossification 
appears to be very constant. The constant existence of 
distinct opisthotic and epiotic elements is doubtful. 

The Frog's skidl is characterised by the development 
of a very singulai* cartilage bone, called by Cuvier the " 08 
en ceinture" or girdle-bone. This is an ossification which 
invades the whole circumference of the cranium in the 
presphenoidal and ethmoidal regions, and eventually as- 
sumes somewhat the form of a dice-box, with one-half of its 
cavity divided by a longitudinal partition. The latter, cor- 
responding with the front part of the bone, extends into 
the prefrontal processes in some frogs, protects the hinder 
ends of the olfactory sacs, and is perforated by the nasal 
division of the fifth neiTe. The septum, therefore, answers 




Fill. 3d. -Sknil of Rana iicultnta, A. fram uhove ; B, I'r 
C, from th« left Bide: -TipaiBsphenoidj ji, girdle-bone ; Z,the 
pont-BotUili." 



THE AMPHIBIAN SKDLL. 



Ilo the ethmoid, the anterior haJf oE the girdle- bone to the pre- 
frontals, or part of them, and the posterior half of the girdle- 1 
bone to the orhitosphenoids of other Vertebrata. Turbinal I 
oBsificationB are developed is the cartilage bonndiiig the I 
nasal capsulea in aame Ainphibia. 

The membroite bones of the Amphibian akoll i 
B'L Frontals and parietala, which, in the Batraehia, muy be I 
d together into one bone. 2, Nazals are generally pre. ■ 
3. The Tomera, always present, are two in number, .] 
e for each side, in all Avi^hibia but Pipa, Sactylethra 
^elobatea. 4. A great parasphenoid covers the base of thS' 1 
11 from the occipital to the ethmoidul region, aa \aTrlfoiit^.'\ 
ind Ganoidei. 5. A membrane bone (Z), called "tempore- ■ 
toid" by Dnges, liea on the outer aide of the snapen- 
1, exteudiug from the aide-wullB of the skull to the 
rtioolai head for the lower jaw. The relations of this 
~ a its upper part ore eimilar to those of the aquamosal 
t the higher Verlebnita, in its lower part to those of the 

n Jjepidosiren. to the preopercnlum of fishes, and j 
p the tympanic of the higher Vertebrala. 

y Two premaxillfe are always developed. The maxillaa are J 
usually present, and maybe connected, as inmost Batraehia^ J 
by C[uadrato-jugal ossifications with the outer side of the end d 
of the euapensorium, in which an OBsification representing 
e quadrate bone is often developed. But the quadrato- 
mgals (and even the maxillte) may be t'epresented simply 
r less ligamentous fibrous tissue, as is the case in 
me UTodela. Pterygoid bones are developed in aU Awphibia, 
kid distinct palatine hones in most, but not all, of the Ba- ^ 
mekia. The enspensorium, which is inclined downwai 
Ind forwards in the lower Urodela. passes almost directly^l 
lownwords, or a little backwards, in the higher 
iraei'tui slopes greatly backwards; and it undergoes the ^ 
e modifications in direction, during the progress of any 
E the Batvachia from the larval to the adult state. 
f In the mandible, the proximal end of Meckel's cartilage ia 

rer, completely converted into a bony articular ! 
iement, but the distal moiety is ossified in some Batracliia. _ 



178 T 

The membiune bon^ of the mandible are a dentary aud 
a Bpleniftl piece, with, perhaps, an angular element. 

The hyoideau M'ch is, in moat Amphibia, connected with 
the Hnspenaorial cai-tilage — sometimeB quite close to its 
origin, BOmetimes near its distal end, in the Urodela. Its 
comuit are stout and well ossified in the Proteidea. In the 
Batrachia they ai-e slender, aai their proximal ends may 
be free. DiBfally. they are connected with a broad lamellar 
body, from the poBterior margin of which two procesees which 
embrace the laryra are nsually giren off. In the peren- 
nibranoiuate Proteidea, the hyoidean arches are ujiited by 
narrow median eutoglosaal and nrohyal pieces, as in Fiahes. 

In the Batrachia, the branchial arches disappBiir in the 
adult; bnt in the Gyvmopkicna and in the Urodela, more 
or fewer of the larv^il branchial arches peraist throughout 
life. 

In the Proteidea there are three or four branchial arches, 
each UBuaJly consiBting of two cartUaginoaB, or oasified. 
pieces on each side. In the Balamandridea, there are, primi- 
tirely, four branchial archea, but of these, portions of only 
the two anterior remain in the ndnlt. Ponr are developed 
in the Cmeilin, and three of these are permanent. 

Some peenlinritieB exhibited by the BkullB of the Gywno- 
phiona, and by the Labyrinihodonia, are worthy of especial 
notice. 

In the former, e.g. in lekthyophU gliiiinosa, the sknll is 
covered by a complete bony roof, formed, mainly, by the 
ex-occipitala, parietala, frontale, prefrontaJB. nasals, and aa- 
oending proceasen of the premaxillariea. Between the ei- 
oocipituls, the parietal, and the frontal, above, the maxilla. 
in front, and the quadrate, behind and below, liea a. bone 
which ttppoara to answer to the bune [i) of the Frog, and to 
its quadrato-jugal. Between the nostril and the maxilla. 
the nasal bone and the premaxiUo, there is a bone which 
seems to be an ossification of the cartilaginous ala nasi. 
Another bone nearly encircles the orbit, and, aa a aupra- 
and postorbital bone, haa no analogue among existing 
Amphibia. The palatine bones surround the posterior and 




t The Labjiinthociont Bkull is furtliev chujacteriHed by th« 
welopment of distinct pointed epiotica, like thoae of' 
•hes, and of paired ossifications, which tiake \he place of J 
p.aapm-ocoipital,aaiamaiiy Ci'anotdei. lamaajliahji' 



18U THE ANiTOMY 

thodonta tbe articalar element of the lower jaw is iK>m- 
pletely osBified. 

Arehegotaitmg poaeeeaed bianohial arebes when young,. 
and there can be little doubt that the other Labjrintho- 
donta reBCmbled it in thia respect, > 

The limbs and their arches are completely absent in tbe^ 
Gymnophiotia, and, apparently, in the extinct Ophiderpetont 
of the Carboniferous formation. In all other J inpAtKo the' 
pectoral arch and limbs are present, and, in all but Siren, 
the pelvic arch und limbs. The anterior and posterior- 
limb arches consist of a continuoos cartilage on each sidey 
divided by an articular surfai^e into a smaller dorsal inoietj^ 
and a more expanded ventral portion. The doraal moietiea' 
are, respectively, the scapula and the ilium. The ventral 
moietiM are divided by notcbea, or fontanelles, into two 
portions — an anterior, precoracoidal, or pubic part, and ^ 
posterior, coracoidal, or ischial part. 

In the Urodela the scapula osaifles, and iU osBificatioa 
may be prolonged into the coi'acoid and precoracoid, but' 
thei'e is never more than one osseous maas. The claviclS; 
is not developed. In Siredon, the Derolrcnuita, ajid Sola-' 
laandridea. the coracoids are received into grouves of the 
anterolateral edges of a cartilaginous stemuuj. 

The pectoral arch of the Labyrinthodonta seems to Lavo 
possessed representativeB of clavicles in the lateral tborai^id^ 
shields. The structure of the rest of the arch is not clear^ 
but ossified coraco-acapular pieces seem to have existed. { 

In the Batratiiia, the coraco- scapular cartilages a; 
times, aa in the common Prog, firmly united in the 
line, and Bend forwards a median proccsa, which becom 
osaified, and is the oniorfemum (Fig. 57, oM.). 
the coracoids articulate nitb a well-developed sternnm (« 
Distinct oseificatious arising on either side of the glee 
cavity represent the scapula (se.) and the coi-acoid (or.), s 
the upper moiety of the scapula may be distinctlj o 
fied aa a aupra-scapula (g.itc.). The coracoid is divided h 
large membrauoTiB spate or /ontiintlh into a proper o 
ooid (cr.), which lies behind the f ontanelle ; 



THE LIHBS C 



AMPHIBIA. 



s epiatracoid {e.er.], whifh Lounila it internally, J 
d a, precaraetnd, which iimita it in front. Closely applied^ 
f the precoraeoid is an oaaificatiou in membrane, whiol 
presents the clavicle, 
^ The pelvic arth ia attached (except in Proteug) to tht 
oity of the sacral rih. An iliiw ossification is alwayl 
sveloped ; an iachial. in all bnt Prtitein. The pubis does notB 

Fig. 57. 




:. 57, —The 5lerniim and pcotoral urchea of a Frog, ae 


en from above.. 


'he led siiprn-Biapula is removed:—"!, acupula; i.ic. 


Bupra-Boapul«t 
aid; cr/.con- 


i.». prpHcapiilorprooeaB; er. coracoid; e.ir. epieoraei 




ia the preoora- ' 




aternam ; i.tt. 


iphUternum. 





appeal' to be regularly represented by a distinct ossification, J 
In the BairncMa the applied flat faces of the expanded^ 
ventral divisions of the pelvic arch iioaleace into a disc, 
^r In the genus Amphiuma, the limbs have each either two j 
pthree digits. In Siren, the anterior limbs, which alona 1 
, we three or four-toed. In Proteua, the anterio)^ 



182 THE ANATOMY OF VEETEBEATED ANIMALS. ^^ 

limbB are tridactyle, the posterior didactyle. Menobranehv» 
has tetradactyle feet, while in the other Vriidela the ajiterior 
limha are tetradactyle, the posterior pentada«tyle. The 
Batraehia have four digits, with or without a rudiment of 
another, in the fore-limb, and five in the hind-limb. In 
the pereunibranchiatu Urodela, the cartilageB of the carpus 
and tarauB, which, except in Proiev*, present httte deiiation 
from the typical number and arrangement (Fig. 11, p. 32), 
remain nnossified ; in the other Urodela, and in the EatTaebia, 
they are for the most pait ossified. 

In the Satrachia, the posterior limbs ai-e much longer 
than the anterior. The radius and the ulna in the fore- 
limb, and the tibia and fibula in the hind-limb, are fused 
together into one bone. The caipal hones no longer prearait 
the typical arrangement ; and, in the tarsus, there are two 
proximal, gi-eatly elongated, cylindrical bones, which take 
the place of a e^caneum and an astragalus, while the distal 
series is reduced. 

The limbs of the Labyrinthodonts were feeble in com- 
parison with the size of the body, In the genera Arehego- 
taitras, Keraierpeton, Uroeordylus, LepterpeUm, each foot 
1 five digits, and the carpus and tarsus were Jm- 



The Amphibia usually possess teeth on the vomere, pre- 
roarillm, maiillaa, and dentary pieces of the mandible, but 
rarely on the palatine and pterygoid hones. Thepremaiillary 
and vomerine teeth are disposed in concentric semicircles, 
an aiTangement which is very characteristic of the group. 
In the larvae of the Batraehia, and in Siren, the premaxilke 
and mandibles are ensheathed in homy beaks, as in the 
Chelmtia and Aves. In addition, Siren has teeth in the 
vomers, and on the splenial piece of the mandible { Meao- 
hranchui and Siredmi have pterygoid teeth. Many of the 
Labyrinthodonts possess palatine teeth. In some Gymno- 
phiona the mandible lias a double row of teeth, and there is 
an approximation to this stmcture in the Labyrinthodonts. 

The teeth usually become onkylosed with the adjacent 



^P THE HEART IN THE AMPHIBIA. ISI^^^H 

^ft bones. In exlating AmphibUi their structure is simple, bat ^^H 
^^in tLe Labp-inthodonta, the parietes of tlie teeth, at n ^^^B 
certain diatanee below the Bummit, become longitudinally "^^1 



^tho 



folded, and each fold miLj be again longitudinallj plaited, 
HO that the transverse section of the tooth acquires a. Tery 
complicated structure, the pulp-cayity being Hubdivided 
into a great many radiating and branching segments. The 
structure is Himilar in principle to that cshibited by the I 
teetb. of many of the Ganoidei. In many of tlie Lahyrin? I 
ihodonts, again, two of the anterior mandibular teeth tak«~l 
m the form of long tusks, which are received into fossse, « I 
mina, of the upper jaw, as in most existing CrocodiliCi.,A 
tongue is fixed to the floor of t!ie mouth in Vroilela and' 
Oymnopliiona, and remains undeveloped in the genera 
Fipa and DaaiyhOtra, which hare thence been termed 
Agloam, In other Batrachia, the tongue, which, is naually 
long, and fixed by its antenor end to the symphysis of the 
unandible, can be i-apidly protruded and used as an orgui . 
mot prehension. No distinct salivary glands have been ob» I 
Vfierved in the Amphihia. Many male SatToehia have thei ■ 
^nuiMJus membrane of the floor of the mouth produced intoj 
pouches which can be distended with air. 

The simple alimentary canal is usually short, and mucb I 

longer in the larvffi (which are vegetable feeders) than ia 1 

ft'tho adults. A gall-bladder is always present. 

Hi The Leart presents two auricles, a single ventricle and&il 

Mulbus arteriosus. A venous sinus, the walla of which g 

rthytlimically contractile, receives tie venous blood from the 

I' body, and opens into the right auricle. InProtsiw, Metiobrim- 

f e/nis, and Sireii, the septum of the auricles is less complete 

than in the other Amphibia, The left auricle ia much smaller 

than the right, and a single pulmonary vein opens into it. 

The interior of the ventricle is more like a sponge than a 

chamber with well-defined parietes. The walls of the long 

bulbuB arteriosus contain striated muscular fibres, and are 

rhythmically contractile. Valves arc sometimes placed at, I 

each end of it, and it may be imperfectly divided into t 




im 'H4H ADAVtJMV or vaUTKnuATED AMnUI£. 

/WMJo \'y 'III lii<i>iiiil>lctn loiigitudinal pattitioo. It u 
lU^mi, i«|Mni Mi'Oi mIiIii. In oillior tbrc^i?, or four. tninkB. i 
MtWd iip'ili III" lirniiiililMl HrchoR. The moBt a 
Mtrnui liCillihi iflvD i>ir IliK I'unitid iivtorica, the a 
Mm |»iliiiiiliMrj' iii'trrliw. btiiI iirtt'ries to the inte 
til* HlM'llo lii'iliikB riirlii t\lf [ii-innipul mote of tl 

III I'mtti; wlini'tt l>lii>ii> un< blirua liranchiaJ arches, tfe 
liillli iif I'liii i\"V\\v ■gillU liitji two tninks; each of theae 
/II^M"*! til ItWi. Iill" I'W" I'lwii'huB, imd then the poet«ii<ir 
('CMtiiibt 'III OMiIi mIiIo. H([iiiil auhdividea into two othen. 
'I'llllli llll'iiK |ial|Hi iif itorlii' ti'iiukit v.\ii formed, which asoeitd 
M|<"ti Mm liVith<dlU1 iMi'lixi. Tli« two miterior pairs of aoitic 
ICIixIki !"!'<)■ •lli'Ki'llv Into the i\>otH of the dorsal aorta, Intt 
nAi'li ultiiH ••II' II viioBiO nlii>'1i«ii1i<rii one of the external gilb, 
l.llit lili^tiil ri'uiii wlili<li 10 Uhoi^'lit Uy iiii efferent canal into 

II liltfl^i'r i<»<i "1 IliK " iioi'tii' iiii'h. The third aortic 

II'iikIi, ••II iwili i>lili>, !■ liiliHTiipti'd, it8 lower part becoming 

I III, lilt hill I iii'|..ii7 i>r II KiU'tufl. Thi? blood is carried out 

<\t IIiIh I'I'iiiii'IiI'i b^ >i vi'iikiih Iniuk, wliinh opens into tlie 

I'liiil. iif I lii> ihirniil Ill, itni! Ih. iii ii'iiUly, mi?rely the upper 

Nil<1'l< iif Hill Milril iiiii'lic Iniiik. 'nio titctfl may he eipreaaed 

III iiiiiilJii'i' wii,v, li,Y ■iijiiiK (bill the bust's of the hraachiol 
NI'liXI'V iiii'l villi! iMKiol^iitiLiHi' ill tlio Unit two gillE. but not in 
Ml" tlilril, 

'I'liu iLiliilli Axnlotl iStiWon) hiiB foni- pairs of aortic 
(j'linlia (il'ltf, ItO, B. p. !t1)i tliu hindcrmost pail' (vi.) ^ves off 
llw iiiiliiiniiKry iirtiTioH, tlie three next (7,, iv., iii.) supply 
liliH uiljtniul lirunoliini i and the anterior trunk passes, ahoTe, 
luto itti iirtery which divides into hjoidean. and carotid 
brunnheii. 

In Bulaiwaidra there are four pairs of aortic tninka in 
thn luliilt, but the upper moiety of the fii^st, on each side, 
tl obliterated, and remains aa a mere duclua Botalli. The 
fourth trunlf gives off the pulmonary artery ; some twigs 
for tbo tBsophagna, and a few cardiac branches, neit arioe 
from it; and it then unites with the second and third to form 
the root of the dorsal aorta. The basal moiety of the firflt 






trunk enlarges at ite extremitj, close to the angle of the ] 
tuandible, into a spongy organ, the. eantid gland, from I 
which the carotid artery, and that for the supply of the I 
ityoidean and oral regions, are given off. 

In the adult Frog, the aortic bulb ia separated by b 
bicomplete longitudinal aeptum into two passages ; an 
Kt its extremity, divides into two trunks, each of which 
partitioned internally into three passages. The middle, 
gy»lemic, passage pasaoB directly into a trunk, which 
litea with it« fellow beneath the spinal eohunn into the 
torsal aorta. The anterior, or carotid, passage ends, as in- ■ 
nSoIaniatuira, in a carotid gland and diictus Botalli ; carotid, .1 
Lyoidean.andoral branches beinggiven off from the former. ' 
The hindermost, or puVmo-dLtaneoue, passage ends in tho •! 
pulmonaiy and the cutaneous arteries, the anastomoses of 1 
these with the I'Oots of the doTsiil aorta being obliterated. T 
The middle pair of aortic trunks thus exclusively constitute J 
origins of the dorsal aorta, and are the permaaeni aorHo T 
;ftes. The right aortic arch ia wider than the left, aspe- 
'ly towards their junction ; aa the left gives off, just before ■ 
point, a large cceliaQO -mesenteric artery to the ab- 
Ikiminal viscera. Each aortic arch gives off llie sabclavian 
id vertebral arteries of itg aide. Only venous blood 
_ les into the pulmonary arteries of a Frog; while mixed 
blood entere the aortic arches, and ia of a brighter arti 
hue at the end, than at the beginning, of the syst£>le. 
blood in the carotid passages is always bright. The n 
obanical arrangements by which this is brought i 
been beautifully analysed by Briicke, who shot 
that the spongy interior of the ventricle contains, 
I base, a transversely elongated cavity, into which 
the auricles open, and which, by its right extremity, com- 
municates with the ventricular opening of the aortic bulb ; 
secondly, that the aortic bulb is imperfectly divided by a 
longitudinal septum, the upper left edge of which ia : 
lower right edge ia free; thirdly, that, oft 
;o which the aortic bulb is thus divided, t 
nan the ligLt side of the septum ends in a chamber. 



1«6 



whicli the eai'otid aud ajate 
that oa the left side eimilarlj leads to the entrance to the 
pulmo-cutaneuus pii:Saages; fotu-thljr, that the carotid gland, 
in which the carotid pciaaage ends, presents a mechanical ob- 
atocle to the flow of thehlood through it; fifthly, that there 
is a valmlar fold open towards the heai-t, in each systemic 
passage, which also offers a certain amount of mechanical 
reaiatajice to the blood ; and, euithly, that after the blood hEW 
begun to flow through the bulb, it will gradually force tbe 




Fig. S8.-Tlie AiDlotl (8!redm). 

septum over to the left side, and ao impede the flow into the 
pulmo-cntaneous paaaage. 

Thus, when the auricular systole takes place, the right 
auricle aends its venous blood into that division of the ventri- 
cular cavity which lies nearest the opening of the bulb; jmd, 
when the ventricle contracts, the blood first driven into the 
bulb is wholly venous. This blood fills the passages on both 
sides of the aeptum, but finds a. very much greater roaistance 
to its exit on the rigbt than on the left side. It therefore 
flows, at first, eiclusively into the left division, and makes 
a way through the short pulmonary arteries into the lasg». 



[ 



' AMPHIBIA. 



III 



the pulmonary veesela till, the pressure on the two 

idea of the septum l>ecomeH equalized, and the ajBtomic 

pasBageB.which offer the next leitBtreaiBtance, fiU with blood. 

which, ia now mixed, as it comes from the middle of the 

Tentricle. Neit, the eeptmii, being driven over to the left 

aide, prevente any mure blood from going into the pulmo- 

Ltaneous passage. At the end of the systole, the blood 

out by the venti-iele ia almost wholly that of the left 

iricle ; and, hy this time, the resistance in the systemic is as 

that in the carotid passages. Hence the latter fill, 

id send arterialized blood to the head. 

The oi^ns of respiration of the Amphibia, in the adult 

Lte, are either external branchiee. combined with lungs, atr- 

the perennibrauchiate Urodela; or lunge rmly, as in ths 

Urodela, the Biitrachia, the Gynmophiona, and, pro- 

lably, the majority of the Labyrint}iod-imta. 

In the perennibranehiate Urodela, the branchial arches 

some of them) are separated by open clefts (the number 

which varies from four to twol. throughout life, and 

three, branched, gills are continued bj single stems into the 

integument, at the dorsal ends of the branchial arches. 

opercular fold of the integument, in fi-ont of the gill-ctefta.^ 

attains a considerable fe-ize in Sixedon (Fig. 58), but does not 

ooTcr the gUls. The branchial archee themselves bear 

branchial filaments. Othei' Urodela are devoid of externa] 

gills, but (as ia the case in Meji-qpoma, and Amph 

present one or two small gill-clefts on each side of the 

neck, and are thence called Derotremata. The rest of tbt 

Urodela, and all the Batrachia and Gymnophiona, are devoid'- 

of both external gills and gill-clefta, in the adult state. 

In all the Amphibia, a glottis, placed on the ventral wall 
of the (Esopha^uB, opens into a short laTjngo-tracheal cham- 
ber with which two pulmonary sacs are connected, either 
directly, or by the intermediation of bronchi {i 
Aghead], or by a trachea (as in the Gymnophiona). The 
%alls of the pulmonary sacs are moi-e or less sacculated. 
tnost AmpkUna the lungs are eq\tal in t 



187 ^H 

tondc ^^^H 



the J 
Ihe ^fl 

ted. ^H 



188 T 

snake-like Oymnopkiona, the light is much smaller than the 
left. In Proteus, the pulmonary blood is not all returned 
to the heart, aome of it entering the veins of the tnink. 
Aerial respiration is effected, in the Amphibia, by pumping 
the aiv fi-om the oral ouvity into the Inngs. To this end 
the mouth is kept shut, and ingress and egress to the air is 
given bj the nasal passages, which always open immediately 
liekind the vomers, at the anterior part of the roof of 
the mouth. Thflse passages being open, and the byoidetui 



Fig. 59. 




Fig 59.~Thc brain of How rKnlmt;. 
timet \~L. ol; liio rhlnencephalon. or 
olfactory nerme; Re, the cerebral he 
mencephnlon with the pineal glonil, Ph. ; L oi>., optic loh«-, C., 
cerebellum ; S. rh., the fiiurth ventricle ( J/u., medulla ohlorgala. 

npparatiw depresBecl, the air fills the cavity of the mouth. 
liie external nostrils are then shut, and the hyoidean appa- 
ratus being raised, the air is forced, through the open glottis, 
into the lungs. 

AIlJinpAifrta possess an urinary bladder, which opens into 
cloaca, and does not receive the ureters. The kidneys of 
Aavgkibia appear, like those of fishes, to be persistent 
USsB bodies. 



^ 
r' 



S KEPBODTTOTITE OBGANS OF 

In the braiii of the Amrphibia the cerebellum is uiwajii 
Bmall, and represented by a mere band ; the cerebral 
spberes aie elongated, and contain TentricleB. 
i(etw the mesencephalon is verj indistinctly marki 
optic nerves form a cfaiaama. 

fishes, the pneumogastiin ^ves off a lateral nervM 
whicb nma along the sides of the body. 

The ejea are Tery email, and covered by the iutegumenl 
Proteus, the Qifmiiiyphiima, and t 

rennibranebiate and derotreme Urodela have no eyelidsf. 

Lt most Bairaehia have not only a well-developed upper 

'elid, bat a niotitating membrane, moved by speciiil musclea. 

AUilmphibta possess a fenestra oriiliB with a cartil^>inouB, 

OBseooB, oohuneUifurm stapes, the eitpaoded proximal 

end of wbicli is fixed to the meuihrane of the fenestra. la 

many Sairaehia, if not in all, there ia a fenestra rotunda,, 

though the presence of a distinct cochlea has not been as- 

The Urodela, the Gymnophiomi, and the Peloba- 

•.a, among the Batrachia, have no tympanic cavity, nor 

lembrane. In the other Biitrachia there are tympanic 

muuicating freely with the throat. Each is 

ised externally by a tympanic membrane, with which the 

iter extremity of the ateni of the stapes is connected. 

the Aglossa, the two tympanic cavities communicate 

with the month by a single Eustachian aperture; and the 

onter end of the atapea expands into a great cartilaginon* 

plate eoextenaive with the tympanic membrane. 

The ducts of the i-eproductive organs of the Amphibia, 

^ke those of the Ocnoidei, always communicate directly wifll 

urinary ducts : and, as in most Ganoidei and all Elimno- 

' "itheproximal end of the oviduct ia open, andcomniu- 

ites with the peritoneal cavity. The male haa no penis. 

papillary elevation of the waU of the cloaca may 

ipresent such an organ. The testes of the male Amphibia 

composed of tubules, and vata effereatia convey the con- 

ita of these away. In the JJrodela. the iiago effereiitia of 

:aach testis enter the inner aide of the corrcapondiag kidney; 

ttftverBe it, leaving its outer side to enter a 



I 



arima'nj duel, which lies on the outer aide of the kidn^, 
ends hliudlj in front, and opens behind into the cloaca. 
The iiriniferouB tubvili alBO paea directly from the outer mar- 
gin of the kidneys into the genito-nrinary duet. In the 
BatTOchia there is likewise a genito-urinarj dnct. and the 
VOJM effereatia run to the inner edge of the kidney Eind 
enter it. In Bontbiaaior it/neug and Digcoglotxas picina, the 
genito-urinary duet receivea the urinary products aiLd the 
spermatozoa, in the same way as in the Urodeta. But, in the 
Frogs and Toads, the urinary tnbuli are gathered together 
into aspeciul small amal nhiuh opens into the gen i to- urinary 
dnct near its lennination in the cloaca, and the vaaa effe- 
rentia pour their contents into this caaal. Under these 
circumatancea, the part of the genito-urinary dnct which 
lies beyond the renal canal may become obliterated, as in 
the Frogs ; or may persist, and play the part of a vexicula sitni- 
nalis, OB in the Toads. 

In the female Amphibia, the kidneys have, aa in the male 
Frogs and Toads, a renal canal which opens into the lower 
part of the oviduct. 

It would appear from these facts that the oviduct in the 
female, and the genito-nrinai'j ducts in the male. Amphibia 
represent both the Wolffian uud the Miilleriajt ducts of the 
higher Yerfebratn. 

In moat Amphibia the ova are impregnated and hatched 
outside the body, hut internal impregnation and incubation 
occur in some of the Vrodela. In Pipa the eggs arc hatched 
in pouches of the dorsal integument, while the male Alytea 
carries them twisted in strings round his legs. 

When hatched, the young are devoid of respiratory organs 
and of liiuhs, and are provided with a long tail, by means 
of which they swim about. Branchial clefts soon make their 
appearance; and ciliated external branchial plumes, like tboee 
of the perennibranchiate Vrodela, are developed. A pair of 
suckers are sometimes formed upon the under-surface of 
Uiemandibular region, and the jawaacquire homj sheaths. 

S. broad opercular membrane is developed in front of tha 



THE DEVELOPMENT OP AMPHIBIA. 191J 

branchial aperture, and, in the Batrachia. extends ove 
erentnally corers the gillB, a, rounded aperture persisting I 
•for a certain time on!j on the left side. The anterior pair I 
;of limha is developed before the poBterior, but in the Frog, I 
■thej are not BO soon visible, being hidden by the opercula».| 
membrane. ^ 

The lungs make their appearance as divertieula of the J 
tentralwall of theoeaophaguB. ThenasalBacsareatfiratmeF^ i 




eye; n,ear; ib, bronchi te ; m, iiiouth ; i, horny jaws; «, (uckori 
if, operoular fold. 
L. a more HilvsucBd Frog's Isrvn ; y. the rudiment of the hind limb ; A 
Iha riiiglB bninohlal aperture The figure has not been reverseil. i 
tbaltblB mieriurc oiipmra to lie on Ihc rijihtsido Instead of Iho lef 

■snrjil iTiTnlutinns of the intemunent. but naeal naasaces nun 



Irft. ■ 

csBcal involutions of the integument, but nasal passages eom- 

municating with the month are soon formed, and both 

aerial and aquatic respiration are completely eatubliahed. 

In the Satraehia. as development proceeds, the eitemal 

I tttanchia) disappear, and are succeeded, functionally, b 

IK^ort branchial filaments developed upon the whole lengt 

^^^f each of the branchial arches, of which there are four. 



192 THE ANATOHry OF I 

Before the development of the InngB the heart has only 
a single auricle ; afterwards, the auricle beeomes divided into 
two. The aortic aa-chea, at first, pass aJong the lisceral and 
liiunchial arehcB to the dorsal aorta, as in other vertebrate 
embryos. When external giUs are developed, each receives 
a loop from the correaponding arch, much as in Proteus. 

When the internal gills of the -BniracAia appear, each aortic 
arch which belongs to a branchial arch splits into two tranka, 
— one which remains directlj connected with the cardiac 
aorta, and another which opens into the dorsal aorta. The 
vessels of the branchial filaments constitute loops between 
these afferent and efferent trunks, which always rem^n 
nnited bj anastomoses. When branchial respiration ceaaes, 
and the branchial processes and their vessels disappear, 
the anastomoses dilate ; the direct communication between 
the afferent and efferent trunks of the second pair of in- 
ternal branchis is i-e-establjsbed ; and they become the 
permanent arches of the aorta. The anterior branchiaa are 
replaced by the carotid glands, and theii' afferent vessel is 
the carotid passage of the adult. The afferent and efferent 
trunks of the third pair of branchite are converted into the 
stem of the cutaneous artery, and the afferent trunk of the 
fourth pair of branchi* into that of the pulmonaiy artery. 
The diagram (Pig- 25, p. 91) is intended to make these 
changes, and the relations of the various trunks to the 
embryonic aortic arches, intelligible. 

The alimentary canal of the Tadpole is, at first, long, and 
coiled up into a close spire, like a watch-spring, in the 
abdomen, but its length becomes relatively less as age ad- 
vances. At the same time, the diet changes from vegetable 
to animal— the young tadpole being chiefly herbivorous, the 
adult, insectivorous. 

In the Urodaia the tail persists, and developes complete ver- 
tebne; but, in the Batrachia. the caudal part of the spinal 
column disappears, for the most part, together with the 
rest of the tail, and only the basal portion of the notochord 
becomes converted into the urostjle, which eventually 
ankyloses with the two hindermost neural arches. 



CHAPTER V. 



11 ReptUia, eo far as tlieir organization ia known to u 
e dietinguiahed from Atiei) by the following characters ;— 
~. The exoekeleton is compoet^ of homj platee (ecaleeU 
1' bonj plates (ecutee), never of featliere. 
2. The centra of the vertebrffi may be amphicailoi. 

IB, opiBthocffllonB, or may have neaily flat artieular 1 
; but theae faces ai'e apheroidal or oval, and are n 
g'lindroidal, even in the cei'vical region.* 

When reptiles poBseas a sacrum, the aacral vei-tebiH 
) large expanded i-iba, with the ends of which the ilil 
pBrticulate, 

4, The sternum is rhomboidul ; and, when many ribs a 
connected with it. the bindermost of these are attached tu 
a single, or double, median backward prolongation (except, 

erhapH, in the Pteroeauriu). The sternum may be con 
tterted into cartilage bone, but Iwith the possible exceptii}: 
t the Fteronawia) is never replaced by membrane Ixmi 
d does not oiaify from two, or more, definite centres. 
t 5. "When fln interclavicle eiiats, it remains distinct from 

e clavicles. 
i 6. The mauus contains more than three djgita i? Dino 
ffivria), and the three radiul digits, at fewest, have claws. 



• ThD 
Kverlebnc or i 



■icular 






ery much tlongad 



UH THE iNATOSTT OF VEETESRATED 

7. In all ensting reptiles, the iiia are prolunged further 
hehmd the a^etabuiiun. than in front of it^ ani the inner 
wall of the acetabnlum ia wholly, or ajmost completelj, 
tjBsified. The pnbes are directed downwards and fcir- 
warda, and. like the iacbio, meet in a. rentral aymplijata. 
In the eitinot DinoganTia. the pelvis eshibitH fonnB tran- 
sitional between the reptilian and the ornithic ortang^. 

1^. The di^ta of the pea are not fewer than three ; and 
the metatarsal bones are not ankjloeed together, or witli 
the distal tarsal bones. 

9. Ia existing reptiles not Fewer than two aortie arches la 
right and a lii^) persist. Two arterial tmnks are giv«a 
off from the right ventriele. or the part of the siii|^ 
ventricle which answers t>> ii. The Ti^noaa and nrberiMl 
carrentB of the blood are connected, either in the heart 
itself, or at the origins of the aortic arches. 

10. The blood is cold. There are usunlly tw>j semiloaar 
valves at the origins of the aortic and palmonury tmnks. 

11. The corpora higemina lie upon the apper aurface of 
the brain. 



icutea. ^"^n 



In Avea, on the eontrary; — 

1. The e:[oskeleton consists of feathers. OsaificaJ 
the dermis are rare, and never take the form of scntea. 

2. In all recent birds, the centra of the cervical Tertefane, 
at least, have aabcjlindricol articular faces. If . as in some 
birds, the faces of Che centra of the other vertebre are 
spheroidal, they are opisthocceloua, which is the rarest 
arrangement among reptiles. 

3. The proper sacral vertebwe of birds — that is to saj. 
those between, or throngh, the arches nf whii;h the roots of 
the sacral plema paa& — have nu expanded ribs abatting on 
the il JT* 

4. The atemnm has no i!ostiferons median bairkward 
prolongation, all the ribs being attached to its sides, Th« 
cartOaginoas sternum is replaced, in the adult, by mem- 

e bone, and ossifies from two. to Sve or more, centres. 




THE DIVISIONS OF THE REPTILIA. 195-1 

•31 an interclavicle exiata it iB confluent with, the ^ 

C. The manuB does not contain more ihaa three dlgita, : 
e than the two radial digits have claws. 

7. The ilia are greatly prolonged in front of the aceta- 
Plniloiii, the inner wall of which is memhranoue. The pubes 

and iBchia are directed backwards, more or leas parallel i 
with one another, and the ischia never meet in a ventral 
Hjmphyais. 

8. The astragalus sends up a proceBS on to the front face ' 
of the tibia, and early ankyloses with the latter bone, 
this character, Birds differ from all existing Eeptilee. The 1 
foot contains not more than four digits. The first meta- 

^ tarsal is, abnoat always, free, shorter than the rest, and 
incomplete above. The other three are ankjlosed together, 
^d with the distal taj-aal bone, to form, a tarso-metatarsas. 
Some of the eitinct Dinosawria closely resembled birds 
in the form of the tibia and astragalus, the immoveable 
union of the two bones, and tlvo reduction of the num.h 
of the digits. 

9. Only one aortic arch, the right, is present. Only o 
terial trunk, the pulmonic, is given off from the rigb^ 

^ventricle. The arterial and venous currents c 
nly by the capiUaries. 

10. The blood is hot. There are thi-ee semilunar ralrea 
Wat the origins of the aortic and pulmonary trunks. In all 
■ existing birds the extremities of the chief pulmonary 
Cpaseages terminate in air-sacs. There is a, rudiment of this 
■.structure in the Obamsleons, and the extinct Fterodactyles 
m Tei7 probably possessed such sa«s. 

11. The corporit biyemina are thrown down to the sides | 
l.and base of the brain. 



The Septilia. — This class is divisible, by well-defined I 
jharacters, into the following groups :- 

The doranl Turtebne (which, like all Ihfi other vertehrit 
1 of transverso procesaeal nre not moves 
■8 the ribs moveshle u 



VERTEBKATKD ASIMALB. 



bvrmBi linnu, uaiinlly nine I 
■yiiiTnatria*), And Iho nti^eri U 
vnntrnl wnlli uf th« thorui uiid 



.ber, one of vhich i> ne^ui aBil 
md jmlred, are developed in iha 

nsn, forming a.plaiinm. 



B. Thedowul vorlobrlr(whWi Imveoilhori 
tniUTerie prncusseii), ata movMlilo u|H>n o: 
iipnn thrm, 'I'liBra U no jilaiitnjri. 

n. The ilorMl vernliriB havo trnniverae proaeMCS, which sie 
either entire, nr iiiily very imperl'actly divided into tenaioal 
faeett ( ISrpiilotponiij/tiii'), 
a. The tnmivecBe pnipoiao»»ro long; tjie limbs well developed, 
with the ill|rlla unlteil liy [he Integument into a paddle ; the 
iternum and iternal rlbt me abaont ur rudimenrary. 
\l.-PI.>imauria. 
A. The tranaverie proomca ue abort, ond somelime* nidi- 
mentary ; the lliiiba pruicnt or aliaenC ; when Ihey are ftill7 
<levelo|Hnl. the <ll|{lti> nrv Tree, and tbece ia b well-devrioped 
alernum wltli atenisl rlba. 

a. A poolortti aroh and urinary bladder. 

m.- ■Luu.rlUla. 

b. No peutorol ardji, and no urinary bladder. 

bs are paddle- 

V.— /c/i%o"i 
:. The anterior dnraal vuitelirie have elongated utd divided traiu- 
veise prucctica, the lubcrcularbolni- longer than the cafll 
divieion {SudvapniidiiUa). 
a. With only (wo vertabriD In the «aoram. 

VI — Crarorfi/in. 

n. With wore thnii iwo verlebr(o in the saoram, 

a. TliB manu« without a prolonged ulnar digit. 

1. The hind li.nb saurian. 

Wl.-DlcynodoHlia. 



^^^ 



1 aliall describe the exoskeletal. eudoakt'lutal. and dental 
uystema of the chief gruups of tlie Jte^tUia, uuder the 
several heads here entiwerated, and 1 shall then give 



I 



account of these systetaa in Anes. But modifioLtiona it 
myology, neurology, splancbology, and development of t 
two claaaes may be conveniently considered together, un ' 
those Beveral heads, in another chapter. 

I. The Chelonia..— The Tortoieea and Turtles are th 
reptiles which njoat nearly approach ihe Amphibia, thoi 
thej depart veiy widely not mei'ely from the amphibian, 
from the ordinary vertebrate type, in Home respects. 

A horny epidermic exoskeleton is absent in the soft 1 
toiaea {Trionyx), the bodies of which are covered by a i 
integument; but, intbeother CAeJonia.the epidermie ia mi 
fied into homy plates, whicli constitute the so-called "1 
toiseshell," and have in general a very definite arraogemi 
The dorsal surface of the body presents three series 
central plates, of wiich five are in the middle and four u 
each Bide (4, 5, 41. The margins of the dorsal shield a 
guarded by twenty-four or twenty-five plates ; one or 
middle line in front, called nmohal; one or two behind, j^ 
and eleven on each side, margiwd. The ventral shield k 
times presents an anterior median scale ; but, more usu 
: pairs, disposed symmetrically. It will be se 
lently, that these epidermic plates by no meai 
I spond with the bony dermal ossifications. In addition t 
these principal plates, smaller scule-like patches of lioni 
epidennis are developed on other paj'ta of the body, &. 
the limbs. 

The dei'mal ossifications may best be described in 
aeotion with the endoskcleton. 

The presiusral veiiebnu are few in number. Ii 
■Qreea Turtle (Chelone midaa) there are eight cervical, a 
ten dorsal, in front of the sacrum, which is composed c 
two vertebiTB. In all the cervical vertebrfe the neurocentral 
autnres persist; there are no trajisverse processes, or ribs. 
and the spines ai-e low or obsolete. The first vertebra, or 
ringlike bone, composed of three pit 
;wo superolateral. The second is a 1 
e ceati-al partof the centrum of the atl 



THE ANATOMTT C 



ANIMALS. ^^^^ 

hing itself to the 



ing apart, as an odontoid bone, and attaching itself t 
front face of the centrum of the aecond vertebra. 

The other cervical vertehrffl are remarkable for the singular 
variety in the disposition of their articular cups and balls. 

Fig 61. 




Thns, the third is opistboccelona ; the fourth, biconTex ; 
the fifth, proccelous ; the siirth, alao proc<BlouH, but the 
poBterior face is nearly flat, and very broad ; in the seventh, 
both the anterior and the posterior faces are Tery broad 
and flattened, the poateiior being the more conrex. The 
eighth cervical vertebra is proccElous, and diflers from the 
rest by the expansion of its neui-al spine, and by the 
HTching backwards of its poatzygapophysea over the convex 
prezjgapophyBes of the first doi"Bal vertebi-a, npon which 
the former play backwards and forwards. 

All the cervical vertebrso are very freely moveable upon 
one another, and confer great fleiibility on the neck. In 
striking contrast with thia arrangement, the ten following 
vertebrsB have flattened faces, firmly united by cartilage. 
If any one of tbeae vertebrte, from the second to the ninth, 
be examined, it will be found that the elongated centrum is 
only looaely united with the neural arch, and that the 
Biinuuit of the neural arch is continuous with a broad flat 
plate of bone, which forma one of the eight median elementa 
of the carapace, or iienral platea (Fig. 62, V). 

There are no transverse processes, but a rib la orticul 



> 



THE CARAPACE OP THE CHELONIA. 

between the centrum and tlie neural arcb. At a short d 
tance from its attachment, this rib passes into u 
plate of bone, which extends upwards to unite auturalljla 
with the neural p]ate; and, in front and behind, becomer ■ 
similarly connected with preceding and succeeding eoittd f 
plates. The rib may be traced along the under-surfaoerj 
of the costal pUte, beyond the outer margin of which y 
protrudes; and its free extremity is received into a pit ii 
an elongated prismatic dermal ossification, which forms 01 
of a series of wargmal plates (Fig. 62, M). 

The firat dorsal vertebra differs from the others ii 
respects. The anterior (ace of its centrum is conca 
looks downwards and forwards, while its prezygapophyse 




Fig. ea.— Trsnaverse section of the skeleton of Cliehaf midaa ii 
Joreal region; — C", ciotrura ; I' expanded neural pluto; C, 01 
plate ; H, rib ; M, mBrginal plale ; P, Iftleral element ol' 

plWtNO. 

e much prolonged, in order to articulate with the coi 

C^sterior face of the centrum and prolonged postzygapc 

T physes of the last cersical vertebra. The spinous pro 

»,of this vertebra does not pass into the bonj michal plate (^ 

L'the carapace, which lies above it (Fig. 63, Nu), and its r " 

expand into a costal plate, but becomes conn 

Ifith the costal plate of the second dorsal Tertehra. 

jural arch of this vertebra ia shorter, from before bacbj 

mrds, than its centrum ; and the neural arch of the si 

lorsal vertebra extends forwards and overlaps the centraiq 

if the first, for the space thus left unoccupied. The rib a 

^e second vertebra is also carried forward, and articulate 



200 



THE ANATOMY OF VBETEBEATED ANIMALS. 



^^H 



not imly with its own eantmm and neural arcii, but with the 
posterior edge of the centrum of the iirat verbebra. 

These arrangementB are repeated by the other dorsal 
vertebrtB and ribs, up to the ninth inclueiye ; but, in the 
tenth, the neural arch occupies onlj the anterior half of the 
centrum of its own vertebra, and the rib ia very small, and 
has no costal plate. 

The imion of the neural and toafa! plates of the eight 
Fig. 63. 




File. Rl.— Doresl view of the campBOB 

pJute; M, marginiil plates ; R.ribs; 1— 8, ncura] platce; CI— CB, 
CDBlal pUlea ; Fy, pygBl platea, 

dorsal vertebra), from the second to the ninth inclusivelj, 
gives rise to the principal part of the carapace, or dorsal 
luuietj of the bonj shell of the Chelonian. The first and 
the tenth dorsal vertebra contribute nothing to the cara- 
pace, theii' smull riba merely becoming attached to the 
i-ristal plates behind and before them. 

In front of the flrat nemul plate, and joined with it hj a 



^■iKiTated sutare, lies a large nuchal plate {Fig. 63, ^h)^H 
^nrliich forms tbo anteiior median boundaiyof the carapaoO^I 
This nucbo] plate eenia down fromita under-surface sS 
median proceaB, which is joined by ligament with the ei- J 
panded nenral spine of the eighth cervical vertehra. Be- m 
hind the eighth ueni-al plate, three other median ji^^af platea-fl 
(Fig, 63, Fy) succeed one another. The anterior two of ■ 
these are naited by sutures with the eighth neural and'B 
costals, and with one another; but the third is (Connected ■ 
externally only with the marginal plates. All three are -■ 
perfectly distiuot from the iubjacent vertebrs. I 

The aides of the carapace are completed, between tlie '■ 
nuchal and pygol plates, by eleven mn.rg inn.l plates (Fig. fl 
WS3, Mj on each side. Eight of these receive the ends c^^^ 
i ribs of the second to the ninth dorsal vertebne. tu tbe^f 
ray already described. H 

i is no doubt that the nii<iha1, the pygal, and thft^| 
p marginal plates of the carapace are membiTtne bones, de-^H 
[ yeloped in the integument, quite independently of eith^^| 
■ ihe vertehrie or the ribs. But it appears that the neura^H 
plates and the costal plates exist, as expansions of th|^| 
cartilages of the neural spines and ribs of the primitiT^^H 
vertebrse, before oasifloation takes place. This being th^H 
case, the neural and costal plates are vertebral and no^H 
dei'mal elements, however similar they may aeem to be t^H 
the nuchal, pygal, and marginal plates. But this ultimat^H 
similarity of bones of totally distinct origin is not moTtf^| 
remarkable here, than in the case of the skull, where th&fl 
parietal and frontal bones stand in the same relation to th&^ 
Bupra-occipital bone, us the nuchal and pygal platea do to 1 
the neural plates of tbe carapace. ^ 

There are no sternal ribs, and no trace of a true stenium 

has yet been discovered in the Chelmtia. The plastron is 

wholly composed of membrane bones, which are developed 

in the integument, and lie, in part, in front of, and, in part, 

Lt^ind, the umbilicus of the ftetua. The latter, at leas^^^ 

Khereforo belong to the abdomen, and the plastron is i^M 

■^beracico-abdumioal structure. j^| 



202 



THE ANATOMY OP VBETEBRATED 




In the Tiu-tle the plaetron conaiatH of nine pieces — one 
median and anterior, four Literal and paired (Fig. 64). These 
pieces may be named — the median, eatoplastron; the first 
lateral, epiplantroni the second, ft joplosfron ; the tisiri, hypo- 
plastron ; and the fourth, lei^hiplasiron.* The entoplastrmi 
and the two epiplaatra correspond with the median and 
lateral thoracic plates of the Lahjrinthodont Ampkihia, 




Fig. 6^,— The pUatron of the Green Turtle (Chiloie mi. , . .... 

inMrclaviole ; cl, clavicles; //y.p., hyoplaatron; JIp.p, hypopla* 
Iron; Xp, liphlplaatton. 

and very probably answer to the int^rclayicle and clavicleB 
of other Vertebrata. 

The sacrum consiBtH of two vertebne. The expanded 
sacral ribs are not ankylosed with the centra and arches 
of their Tertebrai. 

The tiul is flexible, and conBista of pToctslous rertebne. 
The anterior caudal vertebne have no transverse processes. 



■ Believing i 



I pbatron to pisstro 
mum of other hyoclrn 
have riphhti 



(but posaeee ribs wliioli may not become ankyloeed witli 
the centi-a. ThnB the tail and the neck are the only regions^ 
of the apinal cohinm of a Cheloniaji which are fle^ble. 

In the itulla of the Ckehnia all the bones, escept the 
mandible and the hyoidean arch, are immovaablj « 
together. 

I In the occipital segment of the adnlt, the anpra-oceipitial \ 
n united with the epiotic, but the ei-oceipital oauaDy re- j 
maina perfectly distinct from the opisthotic. The biiai- 




^& 



sphenoid ia large and distinct. The aliaphenoidal r^oi^l 
remains unoasified; hot the hirge parietals send down KM 
prolongation on each side, which plays the part of i 
aliaphenoid. Neither the preaphenoid nor the orbito- ] 
ephenoids are represented by bone, but there are large ' 
frontals. In the periotic capanle the large pro-otio ajid 1 
the opisthotic (Cuvier'a oedpiiale exienie) remain distinct | 
bones, bnt the epiotic nnitea with the aupra- occipital. 
Xhe BEwo-ethmoidal cartilage largely persists j 



THE CHELONIAN SKULL. 



■, and jcH 



205 
I the pala- 



FiK. 67. 



JKil plat^ which expands below, 

Ijbe of the palatme biine. 

JB the posterior and upper part of the orhit lies a, 

ntal, and. behind this, a squamonal ia placed at the 

! the periotic capsule, and above the large quadrate 

JThe poatfrontal and eqnamoBal occnpj the upper 

t the temporal region of 

jjl. Below these, a quad- 

jpU and a jagal connect 

tdrate bone with the large 

lu 

pie genei-a, as Ckelone and 

te, the skiiil poasesBee a, 

l^alae roof, formed by the 

ton of a median ridge, de- 

Ifromthe parietal bones, 

iroad plate, which becomes 

^ nnited with the poet- 

S and equamosals. 

qnadrate bone ia fii-mly 

(the sides of the periotic 

Voi the skull, and ends 

m a strong condyle for 

lodibles. The long and 

jfcerygoid hones unite with 

bther in the middle line, 

^ firmly fixed to the base BoW 
in Plsaioeaitriii 

tecodUia. They imite 
hthe upper part of the Fig- G7,~The left half of die 
shorn. n.« in till. laMpp undeniidB of the skull of a 

B none, as m tne laCler Tiirtle; AfSpcrateriornarea, 

latines are fii'mly united with the pterygoids. 
I with the vomer above and in front. They 
j;ed downwards, and develope a short palatine 
hich unites with the produced and expanded lower 
fr, to bound the posterior nares. (Fig. 67. 




206 THE ANATOMY OP VEBTEBRATED ANIMALS. 



The dentary pieces of the two rami of the mandible a 
represented by one bone, as in Birds. 

The hjoideau apparatus conHists of a, broad plate of euf- 
tilage with two longei' anterior, and two shorter posteriw, 
oasified eomua. The comua baye no direct connectioii 
with the skull. 

The pectoral and pelvic arches appear, at first aight, t 
have a very aTtomaloua position ia the Chelonia, inaamnch 
as they seem to be situated inside, and not outside, the 
skeleton of the trank. But since the plastron does not 
answer to the sternum of other Veiiebrata, bat to part of 
the dermal skeleton, the anomaly does not really exist on 
ventral side. And, aa to the dorsal side, the pectoral and 
pelvic ai'cbea of the fcetal Chelonian are at first 8ituat«d in 
front of, or behind, and external to, the ribs, as in other 
Vertebrata. It is only as development advant^es, that the 
first costal plate extends over the ecaptda, and the hindpr 
costal plates over the ilium. 

The pectoral ai'cb ia ossified in such a manner that the 
scapula and preeoracoid form one bone, while the coracold 
i-emains distinct. The free ends of the coracoid and pre- 
eoracoid are usually connected together by a fibro-carti- 
laginous band, representing the epicoracoidul cartilage in 
Laeertilia. There ia no clavicle, unless the epiplastra and 
entoplastron represent that bone. 

The carpus of the Chelonia contains nine primary ossicles, 
as in the (Jrode^o— three in the proximal row, one central, 
and five distal — and these ahnoat always remain distinct. 

There are five digits, the numbers of the phalanges of 
which present no constancy. 

The pelvis contains the usual bunea. The pubea (which 
are very large) and the ischia meet respectively in a long 
symphysis ; and, sometimes, the /ofo miaa obturatoria are 
completed, internally, by the meeting of the bony pubee and 
ischium of each side in the middle line. 

The pelvis is not usually united with either the carapace 
or the plastron, but in Chelyf, Chelcdina, and some other 



THE DIVISIONS OP THE CHELONIA. 

genera, the ilia unite by BynchondroBie, or ankyloais. with 
the last oastal plate, and the pubis and iBchium with the 
xiphisternal plates, so that the pelvie becomes firmlj fixed 
between the carapace ajid plastron. 

The proximal row of the tarsal bones consists usually of 

an aatragedvs, formed by the union of the Uhiale and in- 

termedivaa. and of a fibvlare' ov calcaneum,. In Clwlyih'a 

thei-e is a centrale. In Chehne, Emtja, Testudo, and 

Trionyx, the oenirale is united with the antragalax ; and in 

Emys, the cakanewm coaleaees into the astragaluB, so 

L that the proximal portion of the tarsus consists of one 

I bune. In the distal Beries the two fibular tai-aals ai'e united 

I into a caboid bone. There are five digits, and the fifth 

metatarsal has a peculiar form, as if bent upon itself at i 

right angles, in the middle of its length. 

In the Tesl'odinea there are only two phalanges i 
digit of the pes. 

The Chdonia ai'e divisible into the Testudiniea, thfrj 
Bmydea, the Trionychoidea, and the Euereta. 

1. The Tutudinea have the homy jaws naked and cuttinf 
or denticulated. The eyes ai'e lateral, the tympanic 
brane is exposed, the short and thick limbs have the toi 
(all of which have nails) bound together by the integumenl 
The homy plates of the carapace and plastron art 
developed. 

The Land Tortoises belong to this division. The 
pace is usually very convex, and sometimes (as in the geniuri 
Pyxia) the anterior part of the plastron is moveable, ao4! 
can be shut up like a lid. In Cinj/niis, the hinder part of'j 
tlie carapace is similarly mobile. 

3. The Emydea have, usually, homy cutting jaws, 
fovered by lips; the tympanum exposed, and the limbs i 
slender than iu the Terftidinea, with five-clawed digits 
which are only united by a web. The homy plates of the 
carapace and plastron are well developed. 

These ai-e the Eiver and Marsh Tortoises. They are furthes^ 
divisible into two groups, in the one of which, the Terrapi 



Lgits, 

! the ^1 

rthes^^H 



208 THE ANATOMY OF VEaiEBKATED ANIMALS. 

the pelvis is free, the neck bends in n vertical plane, and the 
bead is almost completely hidden by the carapace vrhra 
retracted (Emyg, CUtudo, ChdyHra), In CUtiido, Cinode- 
«um, and Stavrotypm. the hinder part of the plastron ii 
mobile. In the other division, the CItelodinee, the pelvif 
is fixed to the carapace and plaatron, the neck benda side^ 
ways, and the head cannot be completely retracted under 
the carapace [Cheb/i. Ckdodina). 

3. In the Trionychoidea (Mnd or Soft Tortoises), the jai 
have an extei-nal cutaneons lip; the nasal oi^an is pri 
longed into a kind of snout, and the head is covered by s 
aoft skin without any visible tympanic membrane. The 
limba are flattened, somewhat finlike, and pentadactyle : 
bnt only three digits have nails. The integnment deveilopea 
no horny plates, but is quite soft. The costal platee are 
shorter than in other Cieioniu, and the marginal oseiclea 
lire either rudimentary or absent. 

The genera Oymnopua, Cryptopus, and Cydoderma, c 
stitnto this division; they all inhabit the fresh waters of 
hot latitudes. 

The Eae-retn, or Turtles, have an exposed, hooked, horny 
beak, with a blunt snout. The tympanum is hidden by tlw 
integument. The limbs, of which the anterior pair are 
much the longer, are converted into paddles, the digits being 
much flattened and elongated, and immoveably united 
together hy the integument; only one or two nails are 
developed. The skin of the body is either rugose (Spliargit), 
or covered with thick epidermic plates (Ctefoiie). 

The two genera composing this group inhabit the seas of 
warm elimatea. 

The Cheloma are first known to occur, with certainty, in 
the Lias. Tlie older forms are, in many respects, int^ine- 
diate between the Euereta and the Triottyelimdea, fant preMttt 
no approximation to any other order of ReptUia. 

n. The Ple SI DBA PR I A.— In some of the Piesiosawria. 
the head, not moi'e than one-twelfth or one-thirteenth of 
the length of the body, is moonted upon a neck as long, i 



THE PLESIOSAUBIA, 209'" 

proportion, as that of a, Swan; but in others, thu head is 
lat^ and maasive, auil tht; Deck innch shorter. The hind 
limba are longer than tha fore limbs, tuid there is a compa- 
ratiyelj short tail. The integument was certainly devoid -I 
of any eeutea; and was, probably, emootJi and posaeaaed no I 
scales. 

Tlie eeiTical vertebne may exceed forty in number, though I 
they are generally fewer ; and aa none of the ribs appear to J 
have been connected witli the sternum, or if sach c 
tion eriated it cannot now be traced, it becomes difficult ta4 
distinguish between cervical and doi'sal vertebrw, and o: 
obliged to have i-ecourae to some method of eeparatiiig tbc 
two, differing from that already adopted. Now, in these I 
animals, the neurocenti'al suture persists for a consideiN'fl 
able period, if not thronghont life ; and the Burfacea for | 
the articulation of the oervioul ribs, which are at fii-st alto- J 
gether below the neurocentral sutures, gradually r 
the posterior parts of tlie neck, nntil they firat are cut by.-l 
and then rise above, the auture. It ia very convenient, anil- 1 
harmonizes very well with aome facts to be mentioned by- I 
and-bj in the structure of the CrocoiUUa, to take the last J 
I of the vertebra in which the costal articular amfaee 
out by the neurocentral suture, as the last of the cervical | 

The two anterior, cervical vertabrte, as thus defined, oon- 

Htttute the atlas and axis, and are frequently ankyloaed 

i together. The centra of the other cervical vertebrffi have 

■lightly concave anterior and post-erior surfaces; well-de- 

loped neural arches ; anterior and posterior oblique prn- 

ir zygapophyses, o£ the ordinary chai'acter; and stout, 

mt somewhat abort, spinous proceasea. The centrum pre- 

mta, upon each side, an oval rugoae pit, aometimea more 

T leas divided into two facets. This is the coatal articular 

', which has been already adverted to. Into it fits 

e thickened head of a costal rib, which may have coire- 

mding facets, but is otherwise undivided. The rib is 

mtlnued 1>ack wards into a short and straight budy, and 

p Mi|^ oi the part at which the neck aud the body of 




showing the itrucl _ .^_ 

of the skeleton of PiMiosaBra*.— A, theakull: An, hmbI Bportore.- 
B, the left fore limb : II. humoruB ; U, ulna : K, rttditia ; r. i.t 
rediale.intennediuai, and ulnars, in the prDximil row uf carpal bone. 
I, 2, 3, distsl carpal boaei; Mc, metacarpus; Ph. phaJangcs.^ 
" a dorsal vertebra witli ribs (H.), and ventral oa>IflcBtions( r.o). 
n (ha Isfi hinii limh ; i^, femuT ; F, tibia ; /',fit>[>I>- ' ■' '' t;tii_i_ 



THE PLESIOSAUBIA. 





ire, in Ihe proximal row of toraal bonetl 


1, 2, 3, distill tarsal l)oi 


lapula ; Ca corac^did ; o, clavicles and intar- 


Ihe pectoral arcli : &, ec 


si»vicle(?>.~-F, thepelv 


ic arch : Fb, pubis | Tl, ilium ; Is, ieotiium. 



the rib join, is produced forwarde, bo that the cervical 
of the Plesioeauria have a strong general reHemhlance 
tboae of the Croeodilia. In the posterior part of the m 
and tha ajiterior part of the doraal region, the ribs becoi 
somewhat longer, andloae their ajiteriorprocesBes,graduallj 
Hioqniring the rounded and curved form of ordinary 
Tbeir proximal ends remain simple, and the faceta, 
which they artiaulate, become raised, and thrown ontwi 
am transverse proceBses, developed from the arches of 
vertebrse. (Fig. 6S, C.) 

In the anterior dorsal vertebrffi, these transvei-ae processei 
rapidly acquii'e their full length; and they are continued 
under this form, descending somewhat lower upon the axcbea 
of the vertebrtE towards the aacrum, to the end of thedurs^.] 
region. The neural spines acquire greater length, tfaS', 
zygapophyses are well developed, and the articular sur«i 
"ices of the centra retain the form which they poeaeesetl ■ 
1 the cervical region. There are usually between twenty 

iand twenty-five doraal vertebrEe. The aacral vertebrffi are 
two, and resemble the others, except that the sacral 
riba are laj^e and broad for the attachment of the ilium. 
The caudal vertebrje. usually between thirty and forty 

I number, become, as usual, reduced to little m 
centra at the end of the tail ; but, in the fore part of the 
tail, thej have well-developed spines and articular pro-" 
cesses, with ribs which become ankjlused to the bodies at- 
the vertebree, only late in life. Well- developed chevron 
aes are attached between the ventral margins of 
e centra of the caudal vei'tebrs. 
I As bas been mentioned, there appear to be no sternal 
t there is a well-developed system of ossifications of 
U of the abdomen, arrandted in ti-ansveree rows from 
; backwards; each row conaiats of a median bone. 
f bent npon itoelf, thick in the middle, and thiu at 



I 



212 THE ANATOMY OF VERTEBRATED ANIMALS. 

eact end — and of six other bones, three on each side, 'wbich 
are elongated and pointed at each end, and so dispoeed 
that their pointed ends overlap one another. (Fi", 68, O.) 

In some Fleeiosimria, ae ali-eadj stated, the akull (Fig. 68, A) 
IB Tery small in proportion to the body, not haying more tlian 
a twelfth, or a thirteenth, of the length of the latter; but, in 
other species, the skull is much larger. The snout is taper- 
ing and depressed, and the nasal apertures are situated, 
not at its extremities, hut just in front of the orbits— the 
latter, like the eupi-a-temporal fossse, being wide. The 
occipital condyle is almost whollj developed from tbe stout 
baBi-oocipital. The ei-occipitals give off elongat^l parotic 
processes, and the hasispheuoid is a thick bone, which ends 
in front in a long rostrum. 

There is a well-marked parietui foi'araen, and the pafie- 
tals send off comparatively short processes backwards, which 
become connected with the large squamosals. Tbe latter 
unite with the postfrontala, which separate the orbits from 
the temporal fossa, and the orbit is completed behind by 
the junction of the postfrontaJ with the jugal. The jngal 
bone is continued backwards into a slender bar, which 
eitends as far hack as the lower end of the quadrate, and 
probably contains a quadi'ato.jugal, so that there is a 
distinct infra-temporal fossa. The most obvious circam- 
atanoe in which the skull of PlesioBaurvs differs fi-om. that 
of most Bepiilia is in the great size of the premaxillaries, 
which constitute a large pi-oportion of the snout. 

The under-surface of the sknll is rarely well exposed in 
its anterior part; posteriorly, it exhibits a broad and long 
expansion, formed by the pterygoid bones, which unitd >i 
the middle line, and send processes outwards and backwards 
to the quadrate bone. On each side of the middle line at 
this region of the skull, is seen an ovoidal fossa or deprea- 
sion. The pterygoids ai'e continued forwards, and are 
united externally with transverse bones, and 
teriorly with flattened palatine bones. When the forepart 
of the under-snrface of the skull is eiposed, two other foaaee 
are Tiaible, one on each aide of the middle line, bonndo^ i 



THE FLESIOSACTRIA. 



behind bj the palatine bones, and separated by what app< 
to be the Tomei's. I conceive that these are the true 
terior nares, and that the posterior apertures are simply 
spaces left between the pterygoid hones and thefiasie 

At the sides of the base of the skull, speciiuens of Ple- 
iweatirjts occasionally exhibit two atylif orm bones, which lie 
parallel with the axis of the skull ; these may he parts of 
the hyoidean apparatus. No trace of any sclerotic ring has 
been found. 

The teeth of tiie Flesioiauria are sharp -pointed, curve^ 
and the outer surfaces of their crowns stiiated. iEafiU 
tooth ia lodged in a distinct alveolua, with which, aa in thd 
Crocodilia, it does not become ankyloeed. I 

.The pectoral arch (Fig. 68, B) ia one of the most remarM 
able parts of the organization of the Fleeiosauria, It conJ 
siats, in the first place, of two veiy large coracoids. the lonn 
axes of which are parallel with one another, while their iiwl 
ner edges meet, without overlapping, throughout the greater' 
part of their extent. lu this respect they differ from any 
of the LacerUlia, which are provided with well-developed' 
limbs. In these the long axes of the curacoida always cut 
one another at a large angle, open posteriorly — a circiini- 
Ctance which results from the manner in which the cora- 
coids are received into gi'oovea in the anterolateral edges of 
the rhomboidal part of the sternum. Hence it woulAl 
appear that the Pleniotawria, like the Chelonia, did nofl 
possess anything corresponding to this rhomboidal part ofl 
the sternum, but that the inter^^racoid pai't of the atemunfl 
either absent, or reduced to a mere baud, as in soniS 

'itrachifa, .1 

The scapnlce are unlike the corresponding organs in ann 
other reptile. The glenoidal end, stout and strong, iai 
continued horizontally forwards and inwards, as a. bonyi 
priasi, with a somewhat concave inner edge, and flat inferior *i 
surface. The outer surface, rising up at right angles toi 
the ventral sui-face, gives rise to a well-defined edge: aU 
a short distance from the glenoidal end, the part of tha 
hgjiit wbieh bears this suxfao^ is produced upwards ^M 



2I^^H 

ipeaJ^^H 



— the I 
Haris 

■pata 
^ Tl 



'214 THE ANATOUY OF VBBTEBBATED ANtMA.I.S. 

backwards, into a low recurred plate. This part appears to 
represent the proper body of the acapala in other E.eptiles. 
while the horizontal prolongation anewers to that pre- 
glenoidaiproceaa of the scapula, which extends forwardsand 
inwai-ds as a free bony bar in many Lacerlilia — for example, 
TffuatM. 

In weU-preaerved Bpeeimena, a broad hoop of eubatance 
(Fig. 68, E. a), which seems to have been bnt imperfectly 
ossified, extends across the middle line of the body, from 
the preglenoidal process of one scapula to that of the 
other, and is continued ba«ltwardB in the middle line, to 
the junction of the two ooracoids. This corresponds Teij 
nearly in form and position to the epicoraooidal OBsifioft- 
tiona of the Laeertilia. combined with the clavicleB and 
interolaviclea ; but I have never been able to detect any 
distinct clavicular, or interclaviculeir. elements in any Pbno- 
eaurui'. though they appear to have been well developed in 
NothonailrtiB. 

The humerus is a stoat tone — prismatic, and witli a 
rounded head at its proximal end, flattened and broad 
diatally. (Fig, 68, B.) Its anterior margin is nearly straight, 
oi" even slightly convex, while the posterior is concarei 
Distally, it presents two facets, meeting at an angle, with 
which the broad and short radius undulna articulate. The 
ulna diffei'B in shape from the radius, being convex pos- 
teriorly, and concave in front. The two bones ai-e of equal 
length, and much shorter than the himierus. There are 
six rounded carpal bones,* arranged in two rows; and to 
these succeed live digits, composed of metacarpals and 
phalanges, which are elongated and constricted in. tiie 
middle. The middle digits have numerous phalanges. 

The pelvic arch has very large dimensions, in eorreapon- 
denoe with the size of the hind limb, which is usually longer 
than the fore limb. ^Fig. 68, F and D.) The ihum is a 



THE PniBSIOBAUEIA. 

vevtically elongated bone, narrower below than above, J 
where it becomea connected with the iacral ribe. 
feriorly, it unit<a with the pubia and with the ischium, to 
form the acetabulum. The pubea are very broad quadrate 
bonei, m.uch larger than the iscbia, and thej meet in n 
median eymphjeia. The iachia. triangular and expanded. 
jiIbo unite in a ventral Bjmphyaia. The femur resembles the 
humerus in its general form, although both its sides are 
straighter, and the other bones of the hind limb are so .' 
those of the fore limb, as to need no special descriptioii 

There can be little doubt that all the bones of the limbs | 
like tbose of the Ceiacea, enclosed within a 
lAeath of integument, so as to form a paddle. 

Such is the general organization of the skeleton of the 
Pknotauria, which are long ejitinct animals, entirely o 
fined to the Ifesozoic Rocka, from the Triaa to the Chalk, 
inclusive. They may be divided into two gronps, according 

they ai'c Triaseic, or Post-Triaasic, in age. 

The Post-Triasaic group contains the genera Pleaio»awiu | 
Pliosaarus, the different 8i>ecie8 of which appear to ' 
differ in little more than the proportions of the head to the 
trunk, and the relative length and degree of excavation of 
the centra of the vertebrsB. In the species which have been 
named Pliosav/ma. the vertebrte are wide in proportion to 
their length, and deeply excavated in front and behind, 
FHogavrwi attained gigantic dimensions, paddles of some 
individuals reaching a length of not leaa than aix feet. 

The Triaseic genera, Ifotkosawnia, Simotannrus, Pitto- 
tmurus (for a knowledge of the organization of which w 
chiefly indebted to the laboiira of Hermann Yon Meyer),, I 
appear to have differed from Pksiosannu principally ii 
'wing respects : — 

The connection of the neural archea with the centra d 1 
'ertebrffi seems to have been looaer. The aupra-tem- I 
'al foaaee in the skull appear to have been lai'gei* in 1 
proportion. In these animals, the imder-surface of the I 
skull has the same structure as in Pleaioaaiiirae, but appa. I 
jceai^ lai^ tha poaterioi' iaaas ; while there ii 



216 THE ASATOMY OP 

whatsoever that tlie true posterior narea are eituB,ted (ar 
fornardB, in the poHition aaBigned to them in Plesioaavtut. 
The jiectoiul arch of Nolhosaunis, again, presents a very 
intereating deviation from the PleaioBanriiin type. The 
coraeoida, indeed, are greatly expanded, and meet by their 
inner edges, so that the rhomboidal part of the sternum 
seems to Lave been wholly absent, and the Beapnlee have A 
horisontal prolongation, not quite so long as in Pleiio- 
eaiiras, with an upstanding proper soapular part of corre- 
sponding sbapa But then the ends uf these preglenoidal 
processes are connected together by, and indeed eutiitallj 
united with, a, stout, cnrved, transverse bar of bone, oon< 
aisting of three pieces, one small and median, and two verj 
lai^ and lateral, aU united firmly togethei* by euturea. 
There can be little doubt that the conatitueuta of this bony 
bar correspond with the interclavicles and claviolea dt 
LaeerUlia and IckthyosaTiria. 

III. The Lacehtiiia. — Some few Laeertilia, like the Cha- 
mtuleons and the AmpkigbiBnm. are covered by a soft int^u- 
meut; but, in the majoiity, there is an epidermic exoskeleton' 
composed of hoi*ny plates, tubercles, or spines, or oreiv 
lapping scales. In some forms (e.g. Sdncag, Cyclodtu) the 
dermi beneath the homy scales is ossified, and the body 
has a. complete armour of bony scutes, corresponding in 
form with the scales. The dermal ossifications of the head 
may coalesce with the subjacent bones, but this unicm of 
dci'mal bones with subjacent parts does not occur in other 
parts of the body. 

The apinal column always contains a considerable number 
of vertebra ; and, except in the Amphiebfsnii: and some few 
otber Lizards, the tail is long. Those Lizai'ds which poBoeaa 
hind limbs have a sacrum, into which not more than three 
vertebrffi. and rai-ely more than two, enter. The presacral 
vertebne are distinguishable, when stei-nal ribs are present, 
into cervical and dorsal. All those vertebra; which lie in 
front of the first sternal rib are cervical ; and if. as sometimes 
happens, the last two or three dorsal vertebra: are devoid of 



THE LACKBTIIIA. 217 V 

Tiba, they become lumbar. Not move than nine vertebra J 
are met with in tbe ceiTical region of existing Lacertilia, * 
and tbia number is rare. Tbe number was greater in some 
estinct Lacertilia. 

The atlaa is composed of three pieces, one inferior and 
two anperolateral. The odontoid bone ia eloaely united with 
the aecond vertebi-a, and its anterior face may be cylin- 
droidal. A separate oaaification ia sometimes formed oQ I 
the under-surface of the spinal Golumn at the junction of J 
each pair of vertebne. Such a separate ossification, or sub- I 
■iiertebral med^e-bone, ia commonlj developed beneath and I 
between the odontoid bone and the body of the second I 
Tertebra. 

The centra of tbe vertebrse are either procrelous, or amphi- 
cfElons; tbeformerbeingbyfarthemoreoommon condition 
in existing Lacertilia, all of which, except the Geckos ' ivH 
Bphenodon, have prociBlaus vertebra. The cups and balls 
are usually ellipsoidal, the long axis of the ellipsoid b uing j 
tranave^ie. In the Geckoa, the centra of the vertebne anfl 
oonin&Uy excavated at each end ; and, except in the centre c^H 
each vertebra, where it is ossified, the notochord persiatflB 
throughont the spinal enlunm. H 

The sacral vertebra of existing Lacertilia are not ankWM 
losed togetber, nor are their artit^ular f aees modified, the twol 
being connected by a free cup-and-ball articulation. ThAil 
movements of the two vertebrEs, however, are restrained by 1 
the strong ligaments which connect their neural spines and.J 
arches, and by the fibro-cartilage which connects and coveiaJ 
tbe free ends of their expanded ribs. fl 

In the anterior part of the tail of the Lacertilia thera araj 

usually well-developed subvertebral chevron hones, whioS^ 

are commonly attached to the bodies of the several verte- 

br», and not in the intervals between adjacent vert^bne. 

In many Lacertilia {Lacertce, lyuatiis, Geckon) the caudal 

▼Eortebra have a very singular atnicture, tbe middle of each 

B^eingtraverBedby a thin, unossified, transverse aeptum. Thc^ 

■vertebra natui-ally breaks with great readinesa through tbofl 

H^u« of the septum, and ■whsai such Lizards are - seized ||fl 



218 THE A.NATOMY OF VEBTEBKAIED AHIMA.1^. 



the tail, that appendage is pretty cei-tain to part at one rf 
these weak points. 

The archea of the vertebite of the ItocerHlia are articnlated 
together by the ordinary oblii|tte proceaBea, or zygapophjsea. 
In the Igvaiiix they are additionally connected by a proceu 
of the front part of each arch {zygoepheae), which fita into 
a foesa on the posterior face of the preceding arch {%ygan- 
invm). These Lacertilian vertehriB thua neariy approach 
the vertebra of the Opkidia. 

The transverse proceBses of the vei-tebrffi are very short. 
and ore, at most, divided into two indistinct facets, -with 
which corresponding facets on the proximal ends of the ribs 
artictdate. 

Ribs may he developed in all the cervical vertebre except 
the atlas, and they nsually increase in length towards the 
dorsal region, where more or fewer of tbem become con- 
nected with the sternum. The dorsal moiety of the primi- 
tive cartilage of the rib becomes ossified, and the primitiTe 
cartilage bone is finally repla^red by membrane bone. The 
ventral moiety becomes converted only into cartilage boBe, 
and may pass directly and without articiUation, on the one 
hand into the sternum, and on the other into the rertebral 
rib. Pi'oeosseB are sometimes developed from the posterior 
mai^ina of cei-tain of the ribs, which are termed protxanu 
vnidnati. The sternum, when fully formed, consists of a 
rhomboidal anterior portion, from the posterior angle of 
which a single, or double, backward prolongation is con- 
tinued into the wall of the abdomen. Two or three pain 
of the sternal ribs are connected with the posterolateral 
edges of the rhomboid, while the rest may be attached to 
the abdominal prolongations; or, behind these, they maybe 
continncd into one another, to form complete hoops acron 
the wall of the abdomen (Geckos, ChaiiiffiIc>onH. Scincoids), 

The Flying Lizard (I>ri«:o voIans\ is remarkable for the 
elongation of many of its posterior i-ibs, which are con- 
tinued into, and support, the parachute-like expression of 
the integument by which it is enabled to perform its 
tlights. 



■ tl 



i lulCBBTILIA. 



The skull of tbe LaoertUia reeemLka that of tlie Chelrmia , 
the development of an intei'orbital Beptuia (except u 
the AviphUbceme), and in the absence of alisphenoidB, or o 
amy complete ossification of tlie preaphenoidal or urbito- 
sphenoidal regions. The premaxUlte and maxills are fijmly { 
uitited with one another and with the ekiill, and there are 1 
two Tomera. An lutoHsified apace, the parietal foramen, ( 
nsually lemaina in the runf of the skull in tlie course of the ] 
sagittal suture or betwLtn the purietale and the frontala. 




rrig. S9.-Ttie skul 



longitudinalty biaec 



L Jn the principal group of the Laaertilia, a columu-li 
tnembraDe bone, called the columella (but which is not t 
be, hy any lueana, uonfuuuded with the tiapee, to which t 
«iUU9 uajue is often applied in Septiles), extends from t 



'i'lO THE ANATOMY OF VEETEBRATED AXIMAL8. ^B 

parietal to the pterygoid nn eacli aide, in eloae ewM 
with the memVjranonB or cartilaginons wall of tlie aWl 
Hence they have been culled " Kionocrania," or "coloal 
slnills." This eolumella (Fig. 69, Co) appears to eorrespnri 
with a small independent osaification, ■pchich is eonneelrf 
with the dencending proceaa of the parietal and with * 
pterygoid, in aome CTwIonia. 

In the great majority of the Laeertilia fas in the ChelaaA 
tlie side-wiJls of the akull. in the region of the ear, are pi» 
duced into two broad and long parotic proceaseB, intotb 
compoaition of wbieh the opisthotic, ei-occipilal, and pw 
otio hones enter. Bach qnadrate bone ie articulated withiU 
outer end of oneof theseproceaaes (in which a, amall aeparan 
p(eri>(tc oBaifieation aometimea appeaTB),andis uauallruioTf 
able. TheparietalboneBdotiot unite euturally with theowa- 
pita] eeginent of the skull, or with the pro-otic bones, liW 
are connected with them only by fibrous tiaeue. And aa tin 
prt>Bphenoidul region remains unosaified, or tncompletdj 
oiiified, it follows that the fi-onto-patieial portion of tiu 
skull ia, in moat Lizarda, slightly moveable upon the ofd' 
pito- sphenoidal part. 

Each parietal bone is pi'olonged backwards into a prooM> 
which articulatea with the upper part of the parotic prc- 
longation of the skull ; and to the outer aide of th« posterior 
extremity of the parietal process the sqnamosal is attached. 
The squamosal may be continued fonrard to the post- 
fn>ntal, which ia sometimes subdivided into two. The post- 
frontal may unite below with the jugal, and thus botmd tii« 
orbit. Only in Sphetiodmi, amon^ recent Lizards, is the 
jugal connected with the distal end of the quadrate hj 
bone. As a goner^ rule the quadrato-ju^ ia represented 
only by a ligament, 

In consequence of the structiu-e which has been described, 
the posterior region of the ordinary Laeertilian skull pre- 
gents a numVier of diatinot fosste in the dry state. A nupn- 
temporal fossa lies between the parietal, the postfrontal, 
and the squamosal, on the upper face of the skull ; B.posi-teM- 
pored, between the parietal, the occipital, and the pi 



THE I.ACBKTILIA. 

Ipliysis on the posterior face; a laieral-teijiporal, between 
i aquaniOBal mid poBtfrontaJ above, thejugul and quad- \ 
1 front and behind, and the quadrato-jugal ligament 

f The palatine and pterygoid bonea 
i fiiToly connected both with the 
I bonea, and with the floor of 
3>6 Bkull. Thus the baeisphenoid 
3 off two basipterygoid procesaea, 
3ie outer ends of which aiiicuhite 
|Hth the inner sideH of the pterygoid, 
e poBterior ends of the pterjgoida 
J uBiially connected with the inner 
!B of the diatal ends of the quad- 
e bones. Their anterior ends are 
aly united with the palatines ; and, 
a the junction of the two, a trans- 
free bone (Fig 70 3V) usually paasea, 
i unite the palatine and pterygoid 
b the maxilla 
e anteritr enda of the pilatinea 
Bite with the maxiUje and the vomera ; 
n existing Lacei-tUio they do not 
one amothei or c ime into conta:Ct 
'^rith the basisphenoid or preephenoid i 
in the middle line. The palatine aper- 
tures of the nostrils are placed between 
the palatine bones, on the outer side, Pig. 70,- Under-viBw o 
<«da.e.omer,onll„ime,-. In oal, %'^^S''t^ 
a, few LaeertiUa do the palatine bones aperture. 
send down proceases which bend to- 
wards one another in the middle line, and ao form a posterior 1 
nasal passage, partially aeparated from the oral ci 

The two rami of the lower jaw are usually, though not i 
invariably, firmly oonneoted at the symphysis — and each ie J 
jonipoBed of five oasificattona in addition to the ariiculare. 
•,!rhe hyoidean apparatus conaista of an elongated meditrag 
Lpjtbe ttuterior pact of whicli supports the base of t 




222 THE ANATOMY OF YEBTEBBATED ANIMALS. 

tongue ; and, usually, of two long comua on each side of 
this. The cephalic ends of the anterior comua maybe per- 
fectly free, and lie upon the sides of the neck, as in Pscem- 
mosaurus ; or they may be traceable to, and be connected 
with, the stapes and the parotic processes, as in Sphenodon, 

The limbs may be completely developed ; or only one pair 
(either the anterior or the posterior) may be present; or they 
may be entirely absent. "When present, they may be mere 
styliform rudiments, or may possess any number of digits 
from two to five. Even when the limbs are altogether 
absent, the pectoral arch remains, though the pelvic arch 
seems to vanish. When the pectoral arch is complete, it con • 
sists of a suprascapula, scapula, coracoid (with precoracoid 
and epicoracoid elements), and two clavicles, united by an 
interclavicle, which lies in a groove of the sternum. (Figs. 
12 & 13, pp. 35 & 36.) 

The coracoids articulate with grooves in the anterolateral 
edges of the sternum, and usually more or less cross and 
overlap one another, in front. 

In the genus Lialis, in which not a trace of a fore-limb is 
discernible, there is a small sternum, consisting of a flat, 
somewhat pentagonal, plate of cartilage, in which there is a 
little coarsely granular calcareous deposit ; but this sternum 
is connected with no ribs, nor, though it lies between the 
coracoids, does it articulate with them. Each coraco- 
scapular arch is a continuous cartilage, narrow in the 
middle, but expanded at its dorsal, and still more at its 
sternal, end, where the right overlaps the left, and both are 
connected by fibrous tissue with the sternum. The narrow 
middle part of the coracoid is invested, and in part replaced, 
by a sheath of membrane bone, which expands above and 
below, and represents both scapula and coracoid, though it 
presents no trace either of division, or of a glenoidal cavity. 
Beyond the extremities of this central ossification the carti- 
lage merely presents scattered granular calcification. Along 
the front edge of each coraco- scapular arch, and closely con- 
nected with its ossified part, is a long curved clavicle, en- 
tireJjr composed of membrane bone, au^ 'om\ft^^\>j>a.V\Al^Qr« 



THE LACBBTILIA. 223 

in the ventral median line, by ligamentous fibres. There is 
no interclavicle. The pectoral arch in other snakelike 
Lizards, such as the Blind Worm {Anguis) and the Shelto- 
pusik {Psevdopvs), is in much the same condition as in Lialis. 

When the hind limbs are well developed there is a com- 
plete pelvis. The ilia are moveably articidated with the 
fibro-cartilages which cover the ends of the sacral ribs. 
The pubes and the ischia meet in median symphyses, and 
the anterior margin of the pubis usually, as in the Chelonia, 
gives off a strong curved process. In many Lacertilia a 
partially ossified or cartilaginous rod {os cIocmxb) is con- 
tinued back from the symphysis of the ischia, and supports 
the front wall of the cloaca. 

In most Lacertilia the manus possesses five digits ; and, 
when this is the case, there are usually eight bones in the 
carpus — one for each metacai'pal on the distal side, one 
radial,. one ulnar, and one central. As a very general rule, 
the pollex has two phalanges, the second digit three, the 
third four, the fourth five, and the fifth three (2, 3, 4, 6, 3). 
The pes, also, generally possesses five digits, which increase 
in length to the fourth, the fifth being smaller than the rest, 
and divergent in direction. Two large bones, very closely 
united, or completely fixed together, represent the calca- 
neum and the astragalus, and are articulated, in a manner 
which allows of very little motion, with the tibia and fibula. 
In the distal row there is usually a large bone, representing 
the cuboid. The fifth metatarsal*^ is bent, as in the Chehnia, 
and may articulate with the calcaneum as well as with the 
cuboid. One or two of the cuneiform bones may be present, 
or the inner ones may be represented merely by fibrous 
membrane, or by cartilage ; in which latter case the inner 
metatarsals appear to articulate dii*ectly with the astra- 
galus in the skeleton. The number of the phalanges is 
very generally the same as in the manus for the four tibial 
toes, but one more for the fibular (2, 3, 4, 5, 4). 

* The bone thus named may metatar8a\,but^«QQiTt«i?^T!k.^ca!L% 
perhaps contain a tarsal element, distal tartale. 
Bnd represent not oaly the fifth 



'^'^ THE ANATOMY OF VERTEBRATED 1 

The Lacertilia all possess teeth, which may be confined 
to the premaxille, maiilla), and duntary piece of the man- 
dibles ; or may, in addition, he developed on the palatine and 
pterygoid bones. These teeth are aiiuple in atmctnre, and 
their crowns have very variona foi-ms, bein^ sometimes 
shai-p and conical {Monitor] ; or bladelike, with serrated 
edges {Iguana) ; or with broad, crashing, and spheroidal 
crowns {Cyelt>dne). Aa a general iiile, the teeth become 
ankylosed to the adjacent bone with age; and in the 
upper and lower jaws they thus become attached, either by 
their aides to the parapet of the jaw, when the dentition is 
said to be pleurotUynt ; or by their bases to the summit ol 
the parapet, when the dentition is aerodont. The extinct 
Proioromuria are said to be thecodiml, or to have the teeth 
lodged in alveoli. New teeth are usnally developed at the 
baaea of the old onea. 

IS groups, the leading dig. 



The Laarrtilia are divii 



litpd in Ihe following 
il septum lu 



I.— The pterygoid 
4 colnroelln and an int 

a. AmpiiiciElouB vertcbnc (K. Ampluatlia.) 

a. Deiilition aerodont or pleurodout. 

1. Aiealatota. 

3, Rhj/nchocfphula. 

3. HoiiiiBOMivria.'* 

b. DenlitioE thecodont (?). 

4. Prolonuauria* 

h. Pnicieluus verlebriB {K. procalia,') 
" ■ re IhBJi nine cervlc 



. The 1 
5. Ptati/nota. 



■ingle. 



>1 bonea, two. 
The iiileBumeiit of the head n 
covered wilh epidermic plkte 



I 



* The columella has il 



THE RHYNCHOCEPHALA. 225 

B. No columella ; no interorbital septum. 

12. AmphisbiEnoida. 

II. — The pterygoid and quadrate bones disunited. 

13. CfianuBleonida. 



1. The Ascalahota. — The Geckos, which constitute this 
group, are Lizards of small size, which inhabit the hotter 
parts of both the Old and the New Worlds, and have always 
attracted attention by theii* habit of running with exceeding 
swiftness along the walls and ceilings of rooms. They are 
enabled to maintain their hold under these circumstances, in 
part by the sharpness of their curved, and, in some cases, 
retractile claws ; and, in part, by laminated expansions of 
the integument of the under-surfaces of their digits, which 
appear to act in somewhat the same fashion as the sucker 
of the Bemoraj or Sucking-fish. 

The most important and distinctive characters of these 
Lizards are :— 

Their vertebrae are amphicoelous. 

Neither the upper nor the lower temporal arcades are 
ossified, the postfrontal being connected with the squa- 
mosal, and the maxilla with the quadrate, by ligament. 

The jugal is rudimentary, and the squamosal very small. 

There are no eyelids, but the integument becomes trans- 
parent as it is continued over the eyes. The integument is 
soft, or coriaceous, not scaly. 

2. The Bhynchocephala. — This division contains only the 
very remarkable genus 8phenodon (otherwise Hatteria, or 
Rhynchocephalus). The vertebrae are biconcave. Some of 
the ribs have recurrent " uncinate " processes, as in Birds 
and Crocodiles. The sternal and vertebral ribs are con- 
nected by an articulation, and there is a very peculiar 
system of abdominal ribs. The infra-temporal arcade is 
completely osseous in this, but in no other recent, lizard. 
The quadrate bone is immoveably fixed, not merely by an- 
kylosis with the squamosal, quadi'ato-jugal, and pterygoid, 
but by the ossification of the strong membrane, which, in 
Lizards in general, extends between the quadrate, the ptery- 



^id, a^nd the skuli. and IjouudB tbe frost walls of tlie 
tyinpauum. The dentarj pieces of the mandible are not 
aaturally united. The premaxilla! are not ajikylosed to- 
getlier, and, as in eome other Lizarda (e. g. Uromagtiai), bave 
a heak-hke form, the large prema-iillary teeth hecouiing 
completely fused with the bony substance of the pre- 
maiillffi. There is a longitudinal aeries of teeth upon the 
pala,tine bone running parallel with those on the maxilla, 
and the mandibular teeth are received into the deep longi- 
tndinal groove which lies between the maxillaiy and the 
palatine teeth. By mutual attrition, the three series of 
teeth wear ono another down to the bone in anch a way, 
that the mandibular teeth are ground to an edge, while the 
majtillary and palatine teeth are worn upon their inner and 
outer faces respectively. 

The extinct Lizarda of the Triassic age, Bhyndtoeattnu 
and Hyp^odapedon, appear to have been very closely allied 
to Sphenodan. 

3. The HonuEOBOuna. — The remains of Lizards of small sise, 
and agreeing in the most impoitant points of their osteology 
with the ordinary Lacert'dia, but having amphiccsloua rer- 
tebrffi, have been found in tbe older Mesoaoio rocks, from 
the Solenhofen slates to the Trias inclusively. They cannot 
be identified with either the Bhynckoeephala, or the Aacdla- 
boia, and may be provisionally grouped as EoiiuBoaatBria. 
The genera Somceosanrae, SaphiBOtiaumg, and Telerpebm 
belong to this group, 

4. Ttw Proiorosaitria. — These are the oldest known Boat- 
ropgida. their remains occumng in the Kapferschiefep rf 
Thuringia, which is a part of the Permian formation, and 
in rocks uf corresponding age in this country ; but no morft 
modem represeatjitives of this group are known. 

The Thuringian Lizard (Protoroaauras) does not appear to 
have attained a length of more than mx or seven feet 
The neck is remarkably long, the cervical region being 
equal to the dorsal in length, and it bears a skull of moda- 



THE PROTOROSAUBIA. 227 

rate size. The tail is long and slender, and the limbs well 
developed, as in the existing Monitors. Notwithstanding 
the length of the neck, it contained not more than nine, 
possibly not more than seven, vertebrae, which, except the 
atlas, are remarkably stout and strong. There are about 
eighteen or nineteen dorsal, two (or not more than three) 
sacral, and more than thirty caudal vertebrae. In all these 
vertebrae the neurocentral suture is completely obliterated, 
and the centra are slightly concave at each end. The side 
of each cervical vertebra, after the atlas, presents, near its 
anterior edge, a small tubercle, with which the head of a 
slender styliform rib articulates. The transverse processes 
of the dorsal vertebrae are very shoi*t, antero-posteriorly 
flattened, plates, and the strong ribs are articulated with 
them by imdivided heads. The sternum has not been 
preserved. In the abdominal region of some specimens, 
numerous short and filiform bones appear to represent, 
and correspond with, the abdominal ribs of PUsiosauria 
and Crocodilia, 

The spinous processes of the caudal vertebrae, up to near 
the middle of the tail, have the ordinary structure ; but 
beyond this point they bifurcate, so that each vertebra 
seems to have two spinous processes, a peculiarity unknown 
in other Ldcertilia. a 

The large chevron bones are articulated between the 
bodies of the caudal vertebrae, as in the Crocodilia, but also 
as in some Lacertilia, such as the Geckos. The skull is 
preserved in one specimen only, and in that it is in such an 
imperfect condition that the details of its structure cannot 
be made out. The teeth, however, are nearly straight, 
conical, and sharply pointed, and seem to have been im- 
planted in distinct sockets, though there may be some doubt 
upon this point. 

The pectoral and pelvic arches are large and strong. The 
fore limbs are shorter than the hind limbs, and each limb 
bears five digits. The manus contains certainly eight, pos- 
sibly nine, cai*pal bones, five of which correspond with the 
metacarpals. The number of phalanges is exactly the same 



228 THE ANATOMY 

as in most esieting LacerUlia (2, 3. 4, 5, 3). In the pes, again, 
the number of the phiilangea is characteristically Lacertiiiaii 
[2.3, 4, 5.4), andsoiathoformof thefifthmetatarsal; bat the 
two proximal taj'Bul honee appeal' to have been less dosely 
Dounected together than in exietiug LacerUlia, and there 
were, at fewest, three distal tarsal bones with which the 
metatarsals articulated, and by which they were completelj 
separated from the proximal tarsals. Among existing 
Lacertilia an arrangement similar to this is met with only 
in the Aicalabota. 

5 — 9. The great majority of existing Lanertilia belong to 
the proccelouH ffionocrunia, with not mure than nine cerrical 
vertehrfB, and they deviate but little in their osteology troja 
the general type of oi^anization which has been described. 

The skull in the PMynota, or Monitors of the Old Worid, 
with the Ameiican genua Seloderma, differs from that of 
any other Lncertilia in the circnmstance that the naaal 
bonea are represented by a single narrow ossification. 

In the genus Lacerta the hones of the roof of the BkuL 
become continued into dermal ossifications, which roof 
over the aupra-tcmporal fossfe. In the Chalcidea aoid jS'om- 
eoidea, in which the bi>dy sometimes becomes elongated and 
sna^elilie, and the limbs rudimentary, the supra- andinfn- 
tempural arcades are apt to be ligamentous, and the post- 
frontak and squamosals small. 

10, 37(6 DoUchoaa'aria. — A very singular Lacertilian found 
in the Chalk, and resembling an eel in form and size, has been 
described by Professor Owen under the name of Dalicko- 
eav/ma. It possesses an exceedingly elongated body, but is 
provided with limbs and with a distinct sacrum, consisting of 
two vertebrse. Its most remarkable pectdiarity, however, 
lies in the number of its cervical vertebne, which were not 
fewer than seventeen. 

11. The Mosuaauria. — The cretaceous rocks of Eurt^ 
^uid America have yielded another remarkable lon^-bodud.. 



THE MOSASATTfilA. 229 

jnarine Lacertilian, which attained a great size. This is 
the genus Mosasaurus, remains of which were first obtained 
from the Chalk near Maestricht. 

Eighty- seven vertebrae belonging to one individual of this 
genus have been discovered, and when put together had a 
length of thirteen- and-a-half feet. But there were certainly 
many more vertebrae than these, as those of the end of the 
tail are wanting, and there are gaps in the series of the 
rest. The centres of all these vertebrae are concave in 
front and convex behind; but the concavities and con- 
vexities are less marked in the posterior, than in the an- 
terior, vertebrae. The atlas and axis are not well preserved 
in this series of vertebrae, but the nine following all have 
inferior spinous processes, which become shoi'ter in the 
posterior vertebrae, and, in the last two, are represented 
only by a pair of low elevations. They have short trans- 
verse processes, each terminated by a simple costal facet. 
It is probable that these are cervical vertebrae. In the 
dorsal vertebrae, of which there must have been at fewest 
twenty-four, the transverse processes, which are strong in 
the anterior, gradually diminish in size in the posterior, 
vertebrae. There are no inferior processes. All the verte- 
brae which have been mentioned hitherto have the circum- 
ference of the centrum rounded, and are articulated to one 
another by zygapophyses. But a series of eleven, which 
follow them, have no zygapophyses, and the centra assume 
a more or less triangular prismatic form. The transverse 
processes of these are long, thin, and bent a little downwards 
and backwards. These seem to have been lumbar vertebrae. 
No sacrum has been discovered, but there are numerous 
caudal vertebrae with transverse processes, pentagonally 
prismatic centres, and chevron bones attached to the middle 
of the under-surf ace of each. In the nine posterior of these 
caudal vertebrae the bodies are cylindrical, the transverse 
processes are obsolete, and the chevron bones, ankylosed to 
the undersides of the centra, are long, inclined backwards, 
and overlap one another. And, in the hindermost caudals, 
the spinous processes and the chevron bones disappear. 



' VEETEBKATED ANIMALS. 

There were strong ribs, but nothing is known with a 
tainty of the steraum, limb-arches, or other bonea. 

The very complete specimena of the skull that have been 
diacovered prove that its strQCture was very aimilar to that 
of the Old World Monitors in the large size of the nasal 
apertures, and the fusion of the nasals into a na 
But sharp recurved teeth are ankylosed by their baaea, 
not only to the premaMllary, muKDlai^, ajid dentary bones, 
but also to the pterygoid bones ; and these pterygoid 
hones are unlike those of other LacerUlia, not only in 
form, but because they articulate together in the middle 
line for a eonsideraUe distance behind the poHterior nasal 
aperture. 

12. Tlie Amphkbmnoida.—These Hzarda have eomplatdj 
snakeliku bodies; one genus of the group iChirotea) has 
a pair of small pectoral members, but the rest ai-e apodal. 
The integument of the body is not scaly, but its surface is 
divided into small rectangular arete arranged in trausrerse 
rows. The tail is exceedingly short, so that the vent is 
close to the end of rhe body. 

The numerous procieloua vertebra? have less flliptioal 
articular faces thaii those of the typical Lacert'dia. There 
is no sacrum, and all the precaudal vertebral, except the one 
or two of the moat anterior, have ribs. The representativeB 
of the chevron bones in the tail are £rmly united with the 
centra of the vertebwe. The vertebriB have no zygantmm 
nor zygosphene. jlmp^uikBnahaBnosternani. Chvroteg'hiM 
a Btemnai. but it is iiot united with the ribs. 

The skull, unlike that of LacerfiKa in general, developes no 
interorbital septum. In this respect, and in tie complete 
closure of its anterolateral walls by bone, it resembles the 
Ophidian cranium. There is no columella. Postfrontals 
are absent, and the squamosal ia very small. The quadrat« 
PMBte is small, and inclined not only downwards, but for- 
ner unknown in other Jjacertilia. The two 

mi of the mandible are firmly united by suture. 

'iAwpliislieitii the premaxilke bear two rowi 



THE CHAMffiLEOSIDA. 



ffne beUnd the oiher, and wuu tooth liea upon the eyiuph; 
e premoxills. 



, X3. TAe Clianusleowida. — The ChamEeleons are diatin- 
fuiahed from the Kianocrania not oiily by the negative 
Siaractcr of the absence of the cohimella, which they share 
Wtli the preceding gi'oup, hat by a nnmber of very im- 
mt positive features. Among these I may mention 

e soft and tuberaulat«d skin, witJi its changing hues ; the 
!>Bence of any tympanum; the prehensile tail; and the 
irerj peuuliarly modified feet. The digits are arranged in 
ibundlea of two and three, the nmnns having the poUex, the 
^dex. and the mediuH, syndactylous and turned inwards; 
'Vliile. in the foot, it ie tlie hallux and index only which are 
'tbns united and turned inwarda, the three other toes being 
jitimLlarly connected together bj integument, as far as the 
^gual phalanges, and directed outwards. To these cha- 
^Xacters may he added the remarkable tongue, capable of 
iprotruaion and retraction with almost lightning rapidity. 

The vertebrm of the GbauiiBleons are similar in their 
Iftharaetera to those of the proccelous Kionocrania. The 
igacrum ia composed of only two vertebrai, Only a few of 
t^he anterior ribs are united with the stei'num. A large mini- 
■ber of the posterior ribs, as we have already seen to be the 
n the Gecko, unite together in the mid-line, and foiiu 
contdnuouH hoops across the ventral wall of the abdomen. 

But it is in the structure of the eraniimi that the 
Chamaleonida depart most completely from the ordinary 
~ acertilian type. The parietal bone is not moveable 
mpon the occipital, the supra-occipital sending up a median 
indge, which unites with the base of a corresponding ci-est 

' process extending backwards for a considerable dis- 
Ifljice from the middle line of the parietal bone. The 
■nmmit of this sagittal crest is joined by two curved pro- 
longations of tie squamosal, the three giving the occipital 
TCgion of the Ghomsleon its remarkable casque-like form. 
The frontal bone is comparatively small and single, and 
iiie DOBals are very narrow, and do not bound any part of 



1 



tLc anterior nasal apertoreB. IlheBe apertnree, in fact, an 
aituated upon the aides of the forepart of the akull, a 
scpara.ted from the nasal bones, in part, bj a mciubraiu) 
which Btretchea ontnarda from the nueol bonea ; &ad eitemal 
to tliis by a prolongation forwarda of the prefrontal Looe, 
which unites with the maxilla, and in aome Bpccimena ot 
Ohamffileons ia prolonged forwards into a great oBaeonshom, 
projecting from the sides of the front part of the anout. 

The orbit is eloeed behind bj the aaeending process of 
the jngal bone, but there ia no (jnadrato-jngaJ. The quad- 
rate bone itself is not, as in most other Lacetiilia, move- 
able upon the sides of the stull, but is finnjj aukylosed 
with the bones which He adjacent to its upper end. The 
pterygoid bonea are produced downwards ; and, by a, veij 
exceptional pecnliaritj, do not articulate with the quadrate 
bones, but are connected with them only bj fibrona tie8a& 
In the lower jaw, the dentary piece takes up a very nauch 
larger pi*oportiou of the ramus than ia the cuae in other 
LaeeriOia. The baanl portion of the hyoid ia represented 
by a long median cjlindrica! entoglosaol bone, and its pos- 
terior comua ai'e much stronger and longer than the anterior 
pair. In the pectoral arch the scapula and con 
remarkably longer and narrower than in other Laeer^ta. 
There are no claviclea, and the interclaviele ia wanting, the 
sternum being represented only by its rhomboidal ossified 
cartilage. Again, in the pelvic arch, the ilium is long and 
narrow, and its long axis is directed nearly TertieaUy to 
that of the trunk — in which respect the Ohamiuleona differ 
very much from the ordinary Lacertalia. There ia no M 
daaoee. 

The carpus and the tarauB have a very aingular atructnre. 

In the carpuB there are two proximal bones, articulated witb 

radiua and the ulna respectively. A single spheroidal 

le ia articulated with these, and with the five proximal 

LstituentH of the digits. Besides these, there is an oaeicle 

representing the pisiform. In the tarsus there are also four 

mes, two articulated with tbe tibia and fibula reapectivelj. 

Uiird below and between them, and a fourth distal b 



THE OPHIDIA. 233 

articulating with the five proximal bones of the digits. In 

both manus and pes the number of the phalanges, count- 
ing from the preaxial to the postaxial side, is 2, 3, 4, 4, 3. 

lY. The Ophidia. — This order of Reptiles has been 
divided as follows : — 

A. The palatine bones widely separated, and their long axes 

longitudinal ; a transverse bone ; the pterygoids united 
with the quadrate bones. 

a. None of the maxillary teeth grooved or canaliculated. 

1. Aglt/phodontia. 

b. Some of the posterior maxillary teeth grooved. 

2. Opisthoglyphia, 

c. Grooved anterior maxillary teeth succeeded by solid teeth. 

3. Prcteroglyphia, 

d. Maxillary teeth few, canaliculated, and fanglike. 

4. Solenoglyphia. 

B, The palatine bones meet, or nearly meet, in the base of the 

skull, and their long axes are transverse; no transverse 
bone ; the pterygoids are not connected with the quadrate 
bone. 

5. Typhlopid(P. 

All the Snakes possess a scaly epidermic investment, 
which is usually shed in one piece, and reproduced at defi- 
nite intervals. As a general rule these scales are flat, and 
overlap one another; but sometimes, as in Acrochordus, 
they become more tubercle-like, and do not overlap. In the 
Rattlesnakes {Crotalus) the body is terminated by several 
loosely-conjoined rings of homy matter, which consist of 
the modified epidermis of the end of the tail. 

The derm does not become ossified in the Ophidia, 

The number of the vertebrae in the snakes is always con- 
siderable, and in some cases becomes very great, amounting 
to more than four hundred in some of the large Pythons. 
The spinal column is divisible only into caudal and pre- 
caudal regions, as there is no sacrum, nor any distinction 
between cervical, dorsal, and lumbar vertebrsB. The atlas 



234 



THE ANATOMT OF VERTEBKATED 



ami the odontnid vertebra are Bimilai' to those of the 
Lizards, and the atlua is the only priscaudiLl vert«bra nhicb 
IB devoid of ribs. The centra have nearly hemiBpherical 
articular Burfacea, and thus differ from those of ordinaij 
LucerUlia, -while the superadded articular proceesea found 
only in certain Lizards attain a great development in 
Snakea. The zygapophyaea are broad and flattened, and the 
outer eiu-facca of the anterior pair ai-e commonly prolonged 
into a pi-ocesa. The anterior anrface of the areh above the 




neural oanal is produced into a strong wedge-shaped zygo- 
aphene, which fl.tB into a corresponding zygantrum of the 
next preceding vei'tebra ; and, on the posterior surface of 
the arch, there is a xygantrum for the zygosphene of the 
next preceding vertebra. (Fig. 71.) 

The tranaverae processes are short and tubercle-like, i 
the beads of the riba which articulate with them are simple. 
Sach rib naually givea off a short upward procesa at a, little 
distance from ita head; it is curved, usually ho]low, am 
!«rminatea, inferiorly, in a cartilage which is always free, u 
vace of a sternum existing. Strong descending proeeoses 
OK given off from the undersides of many of the preawin(<i 



THE OPHIDIA. 335 

rtebre. In tlie caudal region, eLmgated tranaverse pro. 
H take the pluce of the riba, Chen-an bones, like thoafi 
f the LacertUia, do not eiiet, hat the caudal vertebrte poH- 
3 bifurcated descending processea, which bear ainiilar 
elationa to the caudal veaaelB. 

The akull differs from the ordinarj Lacertilian cranium 
a the following pointa :— 

1. That yertical elevation and lateral compresaion of thft 
I preaphenoidol region, which, give rise to the intei'orbital 
l aeptum, ia wanting ; the floor of the cranium being nearly 
' flat, and the Tertical height of its cavity diminishing gra- 

ditaUy in front, so that it remains spacious between the 
eyes, and in the frontal region generally. The periotio 
region is not produced into parotic proceaeea. 

2. The boundary- walls of the fi-ont half of the cranial 
cavity are as well ossified as those of its posterior moiety, 
ajid the bones which constitute the bi-aJn-cttse are firmly 
united together. 

3. On the other hand, the naaol aegment ia less com- 
pletely ossified, and may be moveable. The premaxillse are 
iiaually represented by a, single amull bone, which very 
rarely bears teeth. It is connected with the maaiUte only 
by fibrous tissue. 

i. Tlie palatine bones never unite dii-ectly with the 
or with the base of the akull, but they are usually con 
with the maxilla! by tranaverae bonea; and, by the ptery- 
goids, with the mobile quadrate bones. Hence the conneo- 
tiou of the poJato-m axillary apparatua with the otho: 
bones of the akuU ia always less close in Ojihidia than in 
Laeertilia, and sometimes it is exceedingly lax. 

5. The two rami of the mandible are united at the aym- 
phyaia only by ligamentoua fibrea, which are often extremely 
elastic. 

6. The hyoidean apparatus ia very rudimentary, eonaiat- 
ing only of a pair of cartilaginous filaments, which are 
united together in front, and lie parallel with one another 
beneath the trachea. They have no connection with 
stuU. 



I th^^J 



236 THE ANATOMT OF 

These are the moat appiirent difTerencee between tLe I 
Ophidian a,nd the Lacertilian Ekull. But there are othen. 
of a leas obvious but more remarkable chai'acter, bj whidi 
the aVnlls of the Ophidian depart not only from that of the 
Lizard, but from that of other Vertebrata. Thna the I 
sphenoid passes in front of the sella turcica, into a great 
roBtrum, which eitenda f oi-warda to the ethmoidal region. 
and probably reanlts from a paraBphenoidal oBeificatitm, ii 
many adult (}plddia two cartijaginous rods lie in grooves ob 




the upper fEice of this rostrum, and pass behind into the 
basiaphenoid, -while in front they are continued into the 
cartilaginouB ethmoidal septum. These rods are the tra- 
tecwie eraiiii of the fretua, which do not heoome united IB 
Snaltea, its they do in all the other abranchiate Vertebraia. 
The roof and side-wHlla of the Ophidian akull are com- 

'fleted in front of the occipital segment, by two pairs of 
fecroes, which appear to be parietalB and frontale. lb* 

j^btmkal" bonea not only completely wall in ' 



THB OPHIBIA. 237 

the frontal region, bat extend inwards below, and meet in 
the middle Une, above the basisphenoidal rostrom and the 
persistent trabecnlsB. The " parietals " unite sntorally 
with the basisphenoid. These relations are not usual 
in true frontals or parietals (though the latter imite with 
the basisphenoid in Chdania, and the frontals imite in 
the middle line of the floor of the skull in some Mammals) ; 
and as there are only two bones in the place of four in 
this region of the skull, it becomes a matter for inquiry 
whether the two bones, on each side, respectively repre- 
sent orbitosphenoids + frontals, and alisphenoids + 
parietals; or whether they represent overgrown frontals 
and parietals only ; or whether, lastly, they are the result 
of an excessive development of the orbitosphenoids and 
alisphenoids, true frontals and parietals being absent. 
According to Rathke's elaborate investigation into the 
development of the skull in Coluber natrix, the two bones 
on each side are formed from single centres of ossifi- 
cation, which appear in patches of "cartilage," which 
are situated, at first, in the superolateral regions of the 
skull, in the place normally occupied by orbitosphenoids 
and alisphenoids, and that these grow up and meet in the 
middle line. In this case the bones in question are orbito- 
sphenoids and alisphenoids, and Ophidia have no true 
frontals or parietals ; but the existence of so remarkable a 
deviation from the ordinary construction of the vertebrate 
skull cannot be admitted until the development of the 
Snake's skull has been carefully re-examined. 

The Ophidia usually possess well-developed postfrontals, 
and they have large membrane bones in front of the orbit, 
which lie upon the cartilaginous nasal chambers, and are 
ordinarily regarded as lachrymals. Large nasals lie upon 
the upper surface of the nasal capsule between the lachry- 
mals ; and, forming the floor of the front part of the nasal 
chamber, on each side, is a large concavo-convex bone 
( TZ, Fig. 72), which extends from the ethmoidal septum to the 
maxilla, protects the nasal gland, and is commonly termed 
a turbinal, though, if it be a membrane bone, it does not 



23S THE ANATOMY OP VERTEBKATED ANIMALB. I 

truly correspond with the turbinals of the higher VerU- 
brata. The squanioBalB are uBually well developed. Then 
IB no jugal, or quadrato-jugal. 

Though the genei'al conformation of the skull i 
Ophidia is that which has now been desciibed, it preswii 
remarliahle modifications in different members of tbe 
order, eBpeciidly in the form and disposition of the boiMi 
of the jaws. In the great majority of the Ophidia, &e 
elongated palatine bonea have their long aiea longitudinal, 
lie on the out«r eidea of the internal naaal apertui 
do not enter into tte formation of the posterior }>oim^iTies 
of thoBo apertui-es. Each is connected by a tmnarerBe bone 
with the maxilla, which lies at the side of the oral cavity; 
and the pterygoids diverge posteriorly towards the quadrate 
bones, with which tlioy are connected by ligftments. 

But, in the remarkable group of the TypMupida, the 
slender palatine honea meet iipon the base of the skoU in 
the middle Une, and are directed transversely, in suoh a 
manner as to bound the posterior nasal apertures behind. 
as in the Batrachia. There is no transverse bone. Thi 
pteiygoids lie parallel with one another under the base « 
the skull, and are not eonnected with the quadrate bones. 
The maxilla are short plates of hone which are connected 
with the outer extremities of the palatine bones, and a 
dii-ected obliquely towards the middle line of the oral caritj, 
into which theii' free edgea, armed with teeth, depend. 

Again, the first-mentioned, or typical, form of Ophidiaa 
skull eihibita two extreme modifications, between which lie 
all intermediate gradations. At the one end of the scak 
are the non-venomous Snakes, and especially Pythot 
Toririas (which belong to the division Aglyphodontia) ; &t tb 
other the poiaonons Snakes, and especially Crotulvs (JSotmo. 
glyphia). 

Thus, Fytlwii (Figs. 72 & 73) has well-marked premaxills, 

large maxillary bonea, palatine bones which are firmly nnited 

with the pterygoids, and transverse bones whieh bind tie 

maiillaTiea and palato-pterygoid bars into one solid fi 

_ work. 






-JtfjT 



THE OPHIUIA, 

I The maxillariea give attachment to a loi^ a 
Wrved t«eth, which are not very nneqnal in 
h/tlioa (likft Tortrix. but unlike all other Ophidia) poa- i 
PseBaes t^eth in the premaxilliB, 

The aqnamoaal bonea are very long, and adhere to the | 

I sfcull, upon which thej are slightly 

jveable, only by their anterior 

I ends: and the quadrate bones are 

I borne upon the posterior enda of 

[ tbe squamosale, and are thua, as 

re, tliniBt away from the 

I walla of the akull. The rami of the 

y mandible are loosely connected by 

elastic symphysial ligament. 

IB, not only can theae rami be 

ridely separated from one another, 

Bbnt the Bqnamosal and quadrate 

m constitute a Mnd of Jointed 

3Ter, the Btraiglitening of which 

^ermita of tbe separation of the 

I Tnandiblea from the baae of the 

Bkiill. And all these arran^menta. 

taken together, allow of that ini- ; 

mensQ distension of the tbroat 

which is requisite for the passage 

of the lai^e and undivided prey of 

the serpent. 

In Taririx, this mechanism does 
not eiiat, the short quadrate bone Fig. 
being directly ai-ticolat^d with the '^'\ ''ft l"iit t>f thesknIL J 
skull, while the squamosal, Uke the i/,g„^ 
poatfrontal, ia rudimentary. The 
maiillary bonea are also almost fixed to the skull. 

In the Rattlesnakes {Crotalvs, Pig. 74), the premaxillae > 1 
ai'e vei'y small and toothless. The maxillary bone baa I 
no lunger the form of an elongated bar, bnt is shi 
Hubcylindrical, and hollow; its cavity lodges the fo 
f'.rmed by the integument in front of tbe eye, which is 




- Under-i 



240 THE ASATOMT OF VEETEBKATED ANn 



a tliese, ajid Enndiy other, poiaonous Snalcet. 
The upper and inner part of the maxilla articulates withi 
pnllejliite eiirface famished to it bj the lachrymal, so thit 
the uiaxiUa plays freelj backwards and forwards upon ti>*t 
bone. The lachiymal. again, haa a certain amount ot moliaB 
npon the frontal. The npper edge of the posterior waQ of 
the maxilla ia articulated hj B, hingelike joint with tbe 
anterior end of the transreree bone, which has the form of 
an extremely elongated and flattened bar connected poa- 
teriorly with the pterygoid. 




e skull of Cnlalm, viewed from the left aide: B,» 
ition Isken nl tbe point 1} in Fie. A, showing T, U* 
pergietent cartilaginouE trnbeculx. The maiilla is supposed to b* 
trunapnrent, and tlie anterior half of Iho pslatine boae ii 



The latter is long and stoiit, and, as ubuoI, is iiiut«^ ht 
hind, with the distal end of the quadrate hone. Li front 
and internal to, its union with the tranHverae it is prolonged 
forwarda, and bocomea united, by a moveable joint, -with 
short palatine bone, which ia flattened from aide to 



pd lies on. tte outer side of the posterior nasal apertura, 
B anterior eud is connected only by fibrous tissue with the. 
e of tie skuil. The inferior edge of the palati 
» amall teeth, and other sharp, recurved, solid teeth aifli 
M)hed to the uader-surface of the anterioi' nioiety of j 
e pterygoid. 

I "When the mouth is shut, the axis of the quadrate bone 
^ inclined dovrawaniB and backwards. The pteiygoid, 
B far back as it can go, straightens the pterygo- 
hJatine joint, and oausea the axes of the palatine and 
terygoid bones to coincide. The tranByei-se, also carried 
tck bj the pterygoid, similarly pulls the posterior part of! 
laiilla, and causes its proper palatine face, to which i 
i great channeled poison-fanga are attached, to look 
backwards. Henoe these fangs lie along the roof of the 
mouth, concealed between folds of the niueoiis membrane. 
But. when the animal opens its mouth for the purpose of 
striking its prey, the digastj'ic muscle, pulling up the angle 
of the mandible, at the same time thrusts the distal end 
of the quadrate bone forwards. This necessitates the 
pushing forwai'd of the pterygoid, the result of which 
twofold: firstly, the bending of the pterygo-palatine joint j 
secondly, the partial rotation of the manllary upon 
lachrymal joint, the hinder edge of the maxillaiy being; 
thrust downwards and forwards. In virtue of this rota- 
tion of the maxillary, through about a quarter of a cii-cfe 
the dentigerons face of the maxilla looks downwards, and 
even a little forwards, instead of backwards, and the fangs 
are erected into a vertical position. The snate " strikes ;" 
by the simultaneous contraction of the crotaphite muscle, 
pai-t of which extends over the poison-gland, the poison 
is injected into the wound thmugh the canal of the fang; 
and. this being withdrawn, the niouth is shut, all the pr^' 
vious movements are reversed, and the parts return to! 
their first position. 

Ko Ophidian possesses any trace of anterior estremitiea, I 
but the Tij]>ltlo^id<B, the Pythons, Boas, and Tortricee, I 



H 



rndimeute of a pelvie, and tlie latter Snakes even p 
Tery short reprcBeatatiTeB of hind limbs teniiuiat«d bj 

The teeth of the Ophidia iii-e short and oonic-al, and 
become ankyloaed to the hones by which they are anp 
ported. Tiiey may be developed in the premaxilluriea, moi- 
Ularies, palatinea, ptei^goids, and the dentary piece of the 
mandihle. hut their preaenoe in the pretnaxillarieia is excep- 
tional. In UropeliU and some other genera, there a 
palatine teeth ; ajid in the egg-eating African snake, Madtio- 
don, the teeth are small and rudimentary upon all the bonea 
which uBuallj bear them. But the inferior spines of eight 
or nine of the anterior vertebra are long, and tipped, at 
their apices, with a dense enamel-like substance. These 
project through the doreal wall of the {esophagus into its 
cavity, and the eggs, which are swallowed whole, are thus 
broken in a poBitioQ in which all their oontents must neoea- 
saiily he saved. 

In the majority of the non-venomoua Snakes the teeth bm 
simply conical, but in the others, and in all the poisonous 
Snakes, some of the maiillary teeth (which are nsiially 
longer than the rest) become grooved in front. In. the 
SoleHogb/phia. or Tipers and Rattlesnakes , the maxillaiy 
teeth are re-duced to two or three long fanga, the groove in 
the front of which is converted into a canal open at each 
end. by the meeting of its edges. The teeth of the Snakes 
are replaced by others which are developed close to the 
bases of the old ones. 

Ophidia are nut known in the fossil state before 
idder tertiaries. 

V. The IcHTHYOSAUEU.. — In its general form Idithy»- 
miunig presents a good deal of resemblance to a CetaeeiB. 
The head is enormous, and passes at once into the tnii&, 
so that there is no more appearance of a neck than i 
Porpoise, and the body tapers off behind, much as would 
happen in the latter animal were it devoid of a caudal fin. 
Indeed, there is some reason to suspect that the tail of 



THE ICHTHTOaAUKIA. 

Ichthyoeav/ni* may have been proiided with a sort of finlik© I 
espanaion. of the mtegument. This fishlike body was pro- ] 
peUfd, like that of the Flesioswume, by four padiUee ; 
the anterior paddles were plu^^elI close behind the head, and I 
were, generally, veiy maoh larger than the posterior one 




The spinal column is only distinguished into two regions, 
caudal and precaudal, inasmuch astheribe, beginning at the 
anterior part of the neuk, are continued, without being 
connected with the sternum, to the posterior end of the 
body ; and there is no aaerum. The candal region, however, 
is distingnished by the cheyron hones which ai-o attached 
beneath its Tertehrte. The Tertebra of Ichtkyosav 
general have certain characters by which they difier from I 
those of all other Vertebrata, (Fi;". 76, C.) Not only are 
the centra flattened discs, very much hroailer and higher 
than they ai-e long, and deeply biconcave (circumstances 
in which they resemble the vertebre of some Labyrintho- 
donts and Fishes), but the only ti-ausveree processes they 
possess are tubercles, developed from, the sides of thesa . 
centra ; ajid the ncni'al arches are connected with two flat 1 
surfaces, one on each side of the middle line of the upper ] 
surface of the vertebra, by mere Bynchondroses. The neural J 
arches themaelves are forked bones, with only rudimi 
zygapophyseB. and in the greater part of the body do not 1 
become articulated with one another at all. 

In the cervical region, if one may call " neck " the n 
anterior part of the vertebral column, the front part C 
tbe lateral surface ol each vertebra presents two separata 




— OiSerent partB of (lie akeleton of Tchlli^aiavm tHlrrmti/in, 
drawn 10 ihe tame >calti. A, thu skull; B, the fnte limb:— H, 
humerus; R, radius; (A, ulna; r. i. «., radUle, iDtrrmeduiin, DlaBFCi 
Qi, oarpalia ; 1, 8,3. 4,S, digilE; m.r. m.B. radial iniiuluar raipglntl 
OMiclcB.— C, ft dorisi Terlebra, with the rlbi (H) and ventral OMdS- 
o»tioni(F.O).-D, Ihe hind limb: F.fcmur; T, tibia; /£,(ibtdB( 
t, I,/, libiale, intermedium, fibulare; 7V. tststilia; Jl/f, mettttaTMlto ; 
j°A, phalanEeB ; m, II; tibial marglniil oseiclci.— E, the pectoral uril, 
leea trotn the ventral side; F, the sama aspect of the pelvieMjjh^^ 



Ivieimh: 



elevations, orai-ticiiJarsurfaeea.whieb are at firat situated in | 
the upper half of the lateral Burfaoe. Towards the poater 
half of the dorsiil region thej descend, and, gradually 
approaching one another, coalesce into one in the caudal 
vertebne. The form of the proximal enda of the ribs c 
i-eaponds with, the arrangement of these tMbercles ; for, 
where they are aepai-ate, the prosimal end of the rib i 
forked. The lower fork, or capitulum, goes to the capitulat, I 
or lower, tubercle, and the upper branch, or tuberculnni, to 1 
the upper, or tubercular, elevation. In the caudal regios, 1 
where the articular surface ia single, the proximaJ end of . { 
thti rib is also undivided. In the caudal region the riba arft 1 
abort and straight, but in the precaudal region they a 
stout and curved, and much longer in, tUe middle than at 
either end of the series. The atlas and axis resemble the 
other vertebrae in their general form : but a wedge-shaped 
bone is, as itwere, let in between their opposed lower edges; 
and a similar bone, attached to the under-part of the ei 
care face of the centrum of the atlas, aei'ves to complete ths A 
cap for the oecipitai condyle. 

The skull of Ichthyoaaurua (Pig. 76, A) is remarkable for 
the great elongation and tapering form of the snout, the 
huge orbits, the great snpra-temporal f ossie, and the closing 
over of the infra- temporal fossie by plates of bone. Again, 
the two rami of the mandible are united in a Bymphyais, 

' ■which, for length, is comparable to that observed i. 

' modem GJavials and in the ancient Tehoaauria. The basi- 
ocoipital bone furnishes the rounded articular condyle to ^ 
the first vertebra, and becomes very stout and thick in front, j 
It appears to have be«n ankyloaed neither with the bari* ■, 
sphenoid nor with the baai -occipital- The latter bones are 
adapted to its sides, and, together with the supra-occipital, 
which IB interposed between them above, circumscribe the 
occipital foramen. The basisphenoid, a deep and atout 
bone, is produced in front into a long and slender p 
sphenoidal rostrum. There do not appear to have I 
any ossified aliephenoids. The parietals remaij 
tiuvoghout life; and, in some ipeeiMi, not m^^y preae 



d 

N 

e 

y 



OF VEBTEBEATED ANIMA.L8. 

a great parietal foramen close to the coronal Hutwe, Lut 
are completely divided by a median fiHaure. Oasiiied pre- 
sphenoids and orhitoBphenoida appear to have been aixio- 
gfether absent, and tlie frontal bones are relatively small, 
Tbe pro-otic bones are, as nsnal. situated in front of the 
es-occipitaU ; and between the lutter and tbeia there may 
sometimes be discerned a conical bone with a broad base, 
which appears to be fitted in between the es-occipital and 
the pro-otic. If this bone were not so large, it might wdl 
be regarded as a stapes, hut it is possible that, as Covier 
suggests, it answers to the separate opisthotic of the 
Ohehnia. 

In the naso-premaxillary segment, the nasal bones, con- 
tinning the direction of the frontala, atlain considerable 
size, but the premaiillie make up by far the greater part 
of the snout. The maiilhe are reduced, ss in birds, to 
comparatively small and slender rodlike bones, bounding 
only a fraction of the gape. The vomers are elongated, 
and situated in the middle line on the undei'side of tlu 
snout. 

The nostrils are small apertures close to the orbita, 
bounded by the nasal, lachrymal, and prewaxillary bones. 

On each aide of the frontul thei-e is a large prefrontal, 
which passes back above to meet the postfrontal, and thna 
bound the orbit. Below, the maxilla is connected with a 
j'ugal. iProm the postfrontal to the jngal, the postarim' 
margin of the orbit is constitnted by a distinct, curvedi 
postorbital bone (Pig. 76, A, Ft.O). A broad and flat 
quadrato-jugal {Q.J.) passes from the end of the jagal to 
the lower end of the quadrate, and coders in the lower 
and posterior part of the infra-temporal fossa. The apaOfl 
between this bone, the postorbital, the postfrontal, and 
the squatnoaal is occupied by another flattened bone (Fig, 
76, A, St.), which Cuvier calls the temporal, but wbidt 
does not appear to have any precise homologuo amona 
other Beptilia, The squamosal bone is very large and 
stoiit, and forms the postero- external angle of the sknlL 
from this point it suuds a process forwards to me^. 



THE ICHTHTOHADEIA. 



^n 



i 



poatfrontal, inwards to unite with the parietiil, and dowit* 
wards to become connected with the pterygoid. A strong; 
and atout quadrate hone is connected with the exterior of' 
the skull, and presentB apuUey-Uke surface to the articular 
piece of the mandible. 

On the undev-Burfaue of the skidl the long and slender 
palatine bonea ai-e seen, bounding the posterior nares, which 
ai'e situated fai* forwards. Behind, and eeparated hy an 
interval traversed hy the rostrum of the basisphenoid 
bone, the very large pterygoids commence, hy slender and 
pointed ends, which lie on the innei' side of the palatine 
bones at the level of the posterior nares. They then widen. 
and passing backwai'ds with a alight outward curvature. 
on each side of the sphenoidal rostrum, end in three pro- 
cesses — one of which connecte itself with the basiaphenoid, 
another passes outwards and backwards to the quadrati 
while the third runs iipwurds to the squamosal bone. 

The lower jaw is composed of two rami, which 
anteriorly, in a very long symphysis. Each ramus i 
posed of the normal six pieces, the aplenial being 
ably long, and entering eitensively into the Symphysis. 

We have no very clear knowledge of tie structure of 
byoidean apparatus in this reptile. 

The pectoral arch {Pig, 76, E) conaista, upon each sid^^r 
of a narrow scapula (Sc), having the directien usual in 
Jjaeertilia, and a broad coracoid [Oo.), the inner edge of 
which does not overlap its fellow, but meets it throughout 
in the middle tine, as in Plenioeavrug ; so that, in this genua 
also, the rhomboidal part of the sternum appears to have 
^een absent or very small. 

But there is & very distinct T-shaped interclavicle (I.Cl.). 
the backward prolongation of which is received between 
the anterior ends of the coracoids, while its horizontal bar 
is Tary closely united with the inner ends of two stout 
clavicles (CL), the outer extremities of which 
closely 




I. of the 



e of each scapula. This ai-range- j 



et of the clAViolea and iuterdaviale preaents interestii 



^48 THE iNATOMT OF VEBTEBEATED ANIMALS. I 

conditiona intennediate between those obserred in Nothamm- 
nis, on the one hand, and those common in the LaeertUia, OB 
the other. 

The scapula and ooraooid give rise by their jnnetion U> ft 
glenoidal cavity, into which the thick head of the Terj short 
prismatic humenie (Fig. 76, B, Hj is received. The diata] 
end of the humcaTiB presents two facets, which artioulal* 
with a couple of short flattened polygonal bonea, which 
represent the radius and the nlna (if, V), To these succeed 
two rows of smaller polygonal ossicles in the place of a 
carpnH: three, representing the radUile, intermediwm, tatd 
uhmre (r. i. it,), lie in the proximal row, and three or four 
eairpalia (Cp.) in the distal row. With the distal carpal 
bones are connected, by means of the metacarpal OBaictea 
(Jtfc), longitudinal series of very numerous polygonal bonea, 
adapted together by their edges, ajid becoming ^raduallj' 
smaller towards the distal exti-emity of each series. The 
number of complete series does not exceed five, and may be 
reduced to three— so that the paddle may be pentadaotyJe, 
tetradactyle, or tridaotyle. An apparent multiplication of 
the niunber of digits arises from two causes; first, the 
occasional bifurcation of some of the digits ; secondly, the 
Bupei-addition of margitial 6onee* to the radia! and to the 
ulnar edges of the manus (m.M., ni.r.). There is thus formed 
a paddle, which is unlike either that rif a Cetacean, or that 
of a Pi«iui«auni«, or that of a Turtle— departing more than 
any of these struotures from the ordinary form of verto- 
bi'ate limb. 

There is no trace of any sternum behind the pectoral 
arch, bnt the abdominal walls wei'e sti'engthened by a num- 
ber of transverse arcuated bones, similar to those observed in 
the Flegio$av/ria, though not so strong. Each is composed lA 
a median piece with pointed ends, and of some three, or mors, 
lateral pieces, overlapping each other's ends, on each aide. 
(Fig. 76, C, V.O.) 



The pelvis (Fig. 76, F) is not connected by bone witt 

vertebral column. ItconBists of an ilium [It.), an ischiumr 

{laX and a, pabiB (Fb.), uniting together tu form, an ac«ta- 

I balum, nliilc the pubis and ischium of each eide meet 

I the middle line. The ischium ia a narrow and almost rod- 

' like bone, the pubia is somewhat broader, especially at its 

Bymphyaial end. 

The hind limb (Fig. 76, D) hae aubatantially the Bama 
etractnre ae the fore limb, but ia always smaller, and geue- 
1 rally of much less size. 

L The only other bony structure appertaining to Ichthyo- 
I taunm that need be noticed, ia a circle of plates developed' 
' in the sclerotic of the enormous eye, which is frequently 
met with in a very perfect state of preservation. 

It is possible that the Ichtkyoaav/ria occur in the Trias; 
they abound in the Lias and in other rocks of MesozoiA> 
date, up to, and including, the Okaik. 

Some attain gigantic dimensions, and many species hare 
been founded by the differences in form and proportion rf« 
the body and of the teeth; bat no one form is enfficienl 
different from the rest to justify its separation as a distinct 
genus. They may be roughly grouped into such as have 
relatively short saouts and short paddles, with fow carpalia 
(I. intermedUts, coiwamnia. &o.) ; and such as have longer 
snouts, long paddles, and three carpalia (I. longiroatris, 
tewiriroelris, platyodtni) , 

VI. The Cbocodilia. — Orocodiles, the highest Hviog I 
Beptilia, are LacertiUan in form, with long tails and fonB 1 
well-developed Kmbs, the anterior pair being the shorter, J 
and possessing five complete digits, while the hind feet are I 
four-toed. With a single eiception, the living species ha'rd 1 
nails on the three preaxial (radial and tibial) digits, 
that two digits are without nails on the forefoot, and ond \ 
on the hind-foot. The feet arc webbed, but the degree to 
which the web is developed varies greatly. The nostrils aj 
sitaated at the end of the long snout, and can be closed. 
The tympanic membraiiee oi-e expoaed, hut a cutaoeona 



249^ ^H 

ths'^H 

eta- ^^ 



250 THE ANATOMT OF YEBTEBBATED ANIMALS. 

valve, or earlid, lies above each, and can be shut down 
over it. All are partially aquatic in habit, and some (the 
Gavials) are completely so. None of the existing genera 
are marine, though many ancient CrocodiUa inhabited the 
sea. 

The dermal armour is composed of scutes covered by 
epidermic scales of corresponding form. When the armour 
is complete — as in Caiman and Jacare alone among existing 
Crocodilia, in Teleosaurus and StagonoUpis among extinct 
forms — it consists of transverse rows of quadrate bony plates, 
disposed so as to form a distinct dorsal and ventral shield, 
separated by soft integument, in the trunk, but united into 
continuous rings on the tail. The scutes of the same row 
are united sut\u*ally ; those of each row overlap their suc- 
cessors, which present smooth facets to receive their under- 
surfaces. In existing Crocodilia, in the extinct Crocodiku 
Hastingsioef and in Stagonolepis, each ventral scute consists 
of two pieces, a small anterior and a large posterior, united 
by a suture. The scutes always exhibit a pitted sculpture, 
and those of the dorsal region are ridged longitudinally, 
while the ventral scales are always flat. More or fewer 
dorsal scutes exist in all crocodiles, and those upon the 
neck sometimes form distinct "nuchal" and "cervical" 
groups, distinct from the dorsal shield. The dorsal scutes 
do not always overlap, and the ventral scutes are absent, or 
incompletely ossified, in most existing Crocodilia, 

In these reptiles the vertebral column is always thoroughly 
ossified, and marked out into distinct cervical, dorsal, lumbar, 
sacral, and caudal regions. The number of the presacral ver- 
tebrae is twenty-f om' ; that of the sacral, two, in all the recent 
forms, and probably in the extinct genera also. The num- 
ber of the caudal vertebrae varies, but is not less than 
thirty-five. The number of the cervical, dorsal, and lum- 
bar vertebrae varies ; but there are usually nine of the first, 
eleven or twelve of the second, and foui% or three, of the 
third description. 

In existing Crocodilia all the vertebrae, except the atlas 
and axia, the two sacvals, and t\ie ^at c».u^\iV,«jc^^xQQ,cBlous. 



THE CROCODILIA. 251 

The majority of the pre-cretaceous Crocod4Ma have the cor- 
responding vertebrsB amphiccelous, the concavities of the 
centra being very shallow. One genus, Streptospondylvsy 
which is perhaps Crocodilian, has the anterior vertebrae 
opisthocoelous. It is characteristic of the CrocodUia, that 
the centra of the vertebrsB are united by fibro-cartilages, 
and that the neurocentral sutures pei*sist for a long time, 
or throughout life. 

The atlas is composed of four pieces, an upper median 
piece — ^whichis sometimes divided into two, and is developed 
in membrane apart from the rest — ^being added to the 
three pieces found in LacertUia and Chehnia, A large 
odontoid bone is closely united to, but not ankylosed with, 
the anterior flat face of the second vertebra. A pair of 
elongated, single-headed ribs are attached to the inferior 
piece of the atlas, and another similar pair to the os odon- 
toidum and to the second vertebra, by distinct capitular 
and tubercular processes. The other cervical vertebrae all 
possess ribs with distinct and long capitula and tubercula — 
the latter attached above the neurocentral suture to the 
neural ai*ch, the former to the centrum below the neuro- 
central suture. The body of each cervical rib, after the 
second, and as far as the seventh or eighth, is short, and 
prolonged in front of, as well as behind, the junction of the 
capitulum with the tuberculum; and the several ribs lie 
nearly parallel with the vertebral column, and overlap one 
another. The ribs of the eighth and ninth cervical vertebrae 
are longer, and take on more the character of the dorsal ribs, 
the ninth having a terminal cartilage. 

The points to which the capitula and tubercula of the 
ribs are attached are raised into tubercles ; and, by degrees, 
these become elongated into distinct capitular and tuber- 
cular processes, between which, in the third to the ninth 
vertebrae, the neurocentral suture passes. But in the tenth 
and in the eleventh vertebrae, the capitular process, which 
lies nearer the neurocentral suture in the posterior than 
in the anterior cervical vertebrae, risett ut^otl \\i^ Vi^-^ <A 
the vertebra to the level of the neuxocentraX svstox^, V^ 



25a THE ANATOMy OF VEBTBBEATED ANIMALS. 

which it ia traversed, and the tubercular process beoomee 
longer than it. (See Fig. 5, p. 15.) The terminal cartilarge ia 
nnited with the Btermtm by a ateraal rib, whici. may be- 
come more or lesa completely converted into a. cartil^ 
bone, and is articulated with the vertebral rib. 

In the twelfth vertebra a sudden change in the charactK 
of the transverse processes takes place. There is no longw 
a capitular, distinct from a. tubercular, process, but one 
long '■ transverse process " takes the place of both. A sOT 
of step in the base of this process bears the capitnhm 
of the rib, and answers to the capitular process of the cer- 
vical vertebrtB, while the outer end of the pruceas articulat^e 
with the tuberculum of the rib, and represents the tubercukx 
process. The neurocenti-a! suture, in this and the succeed- 
ing dorsal vertebne, lies below tbe root of the transverse 
process, which, therefore, is wholly a product of the neunl 
arch. Neither the capitular pi-ocesses, nor that part of Ihe 
dorsal transverse process which represents them, have dis- 
tinct centres of ossification.* 

In the succeeding dorsal vertebra the "step" of Qie 
transverse process gradually moves outwards, until at lengdl 
it becomes confounded with the tubercular facet, and a cor- 
responding change takes place in the proximal ends of tite 
ribs, in the hindermost of which the distinction betwoei 
capituliun and tuberculum is lost. 

The lumbar vei'tebrss have long transverse processes wbifii 
arise from the neural arches, i.e., above the neurooentnl 
suture. 

The centra of the two sacral vertehne have their applied 
and firmly united faces flat, their free faces concave ; cm 
quently, the first has the anterior face concave and die 
posterior flat, while the second has the anterior surface flat 
and the jjosterJor concave. Each sacral vertebra bas t 
strong rib expanded at its distal end ; and wedged in, at 

• TLua, if (t be m part of the pBr( of the definition of & " p 

tlefinitiDa nf a ^^ panijuyphj/ah,'* pophyni *' Lhat il arifle&trom the 

that It is ttiilogeiiua«. tliere are centrum, Iha doraal verlebrK of 

larapophyses in the vertebnc Ilie Criicadilia have no parmM- 



lO pari 
f tbe 



CroaodUiai and, if it b« phyies. 



I THE CaOCODHlA. 253 

proximal end, between rough sutural surf u^ea fiimiHiied by 
the neural arch above and the centrum below. 

The first caudal vertebra is biconvex, bat all the others are 
pi-occslona ; those of the anterior moiety of the tail have long 
riba fixed in between the neural archea and eeuti'a, as in ' 
saovum, and becoming ankylosed in that position. Chevron 
bonea are attached to the posterior edges of the centra of 
the vertebrce, except that of the first, and those of the pos- 
terior part of the tail. 

From seven to nine of tho anterior dorsul riba are united 
with the sternum by sternal ribs, the form of which vai 
a good deal in different Crocodilia, being aometimea narri 
sometimes bi-oad and flattened. An elongated plate of 
cartilage, which may bo partially converted into cartilage 
bone, is attached to the hinder margin of several of the 
most anterior ribs, above the junction between the ossified 
and the cartilaginons part of the vertebral rib. (Pig. 5, P.m. 
These are the so-called "oncinate processes," which also 
exist in Hatteria, and reappear in Birds. 

The sternum consists of a rhomboidal plate of cartilage 
bone, with the posterolatenil edges of which two pairs of 
sternal ribs ai-ticnlate. The posterior angle of the plate is 
continued into a median prolongation, which, at length, 
divides into two curved divergent comna. From five to 
seven pairs of sternal ribs are united with the prolongation j 
and its comua. A long and slender interclavicle lies in a 
groove of the middle of the ventral face of the rhomboidal . 
part of the stemiun. 

In the ventral wall of the abdomen, superficial to the 
recti muscles, lie seven transverse series of membrane bonea, 
which are termed "abdominal ribs;" though it must be 
recollected that they are quite distinct from true ribs, and 
i-ather coiTespond with the dermal ossicles of the Labyrin- 
thodanta. Each series is composed of four elongated and 
more or leas curved ossicles, pointed at each end, and so 
disposed that inner ends of the inner pair meet at an 
angle, open ba^;twarda in the middle hne, while tlieiv outer 
^■ nr l° overlap the inner ends of the outer pair. The mo|d 



254 THE ANATOMY OF VESTEBKATED AHUIA.LB. ^H 

poBterior of theae OBsictes are Btronger than the othera, and 
are closely connected with the pubic cartilages. 

In the Crocodilia,!! akull the following are tKe cliief peco- 
liaritiea which are worthy of especial notice: — 

1. There is an intei-orbital Beptum, and the prespheaoidil 




Fig. TT.— I.ongituilinfll and . ... 
skull of a Crocodile :— £«, Flueti 
P, pituitary fossa. 



1 cartilaginous, i 






and orbitoaphenoidaJ regions 
incompletely ossified. 

2. All tjte bones of the skidl (except the omndible, st^pv, 
and hyoid] are firmly united by sutures, which pa»Bt 
throughout life. 

3. There ai'e large pai-otic proceases. Both the upper 
and the lower temporal arcades are completely ossified, 
formed by postfrontal, equamoBal. jugaJ, and quadrato-ji 



post-tempoinl ^^^| 
their relatJTS' ^^^| 

^loiip Tuiliitinp ' 



THE CBOCODILIA. 25S 

i Bupni- temporal, lateral-temporal, and post-tempoinl 
■e formed, as in the Laeeriilia, though their relatiTa' 
e very different. 

4. The m^illary and the palatine bonoB derelope palatine 
Palates, which unite suturallj in the middle line, and aepa- 
r rate the nasal pasangea from the cavity of the mouth, as in 

Mammalia; and in all existing Crocodiles, but not in Telso- 
saurug or Behdon, the pterygoids are also modified in the 
same way (as in Mymereoplinga among MammalB), bo that 
the posterior nares arc situated very far back beneath the 
base of the ektdl. 

5. In consequence of the development of these palatine 
plates of the maxillaiy and palatine hones, the two vomen^ 

' 1 most Crocodiles, invisible upon the nnder-surfacd 
I of the bony roof of the mouth. 

6. There are large alisphenoids, but the orbitoephenoids 
ire absent or rudimentary. 

7. There is no parietal foi-amen. 

8. The quadrate bone is very large, and fixed immoveabl 
to the walls of the skull, as in the Chdonia ; and, as i 
latter, the pterygoid hone ia firmly connected with the 
of the skull, and united only with the upper and iunei 
face of the quadrate bone, 

9. The pterygoid sends down a large free process, agai 
the broad outer edge of which the inner surface of 
mandible plays, 

10. The tympanic cavity is completely bounded by bom 
The pro-otic and opisthotic (which ia united with th) 
ex-occipital) form its inner walla, the quadrate its outer' 
wall, the squamosal and postfrontal its roof, and the quad^ 
rate, the basi-occipital, and basisphenoid its fioor, Tba 
two tympana ore placed in communication with the cavity 
of the mouth by three canals — one large, opening in the 
nuddle line ; and two smaller ones at the sides, on the base 
of the skull, behind the posterior narea. The large canal 
passes up between the basisphenoid and bast- occipital, and 
divides between those bones into a right and left lateral'i 
canal. Each lateral qanal Bubdividea into an anteri( 



' TEETEBEATBD ANIMALB. 

brancb, which traverees the basisphenoid, and a posterior, 
which pftaaes up in the ba si -occipital. The posterior bramoh 
ivceives the nairow latei'al 'canal of its side (which roai 
vertically i:p to it), and then opens into the poBterior part 
of the floor of the tympanum. The anterior branch openB 
into its anterior walL 

The tympanic cavities of embryonic Crocodiles communi- 
cate with the mouth by wide and simple aperturea, and the 
complicated arrangement of canals just described reaoltB 
from the great downward development of the baeispbeitoid 
and basi-OGcipital, and their encroachment upon these aper- 
tures on the inner side, while the quadrate bone narrows 
them on the outei-. 

In adult Croeodilia, air-pasaages ertend from each tym- 
panum to that of the opposite side, through tUe bones 
which form the roof of the posterior region of- the BkuIJ, 
On the other hand, they eseavate the quadrate boue, from 
whence the air passes through a membranous tube into the 
hollow articular piece of the mandible. The hyoideao 
apparatus is greatly simplified, consisting only of a broad 
plate of cartilage, which may become partially ossified, 
and of two ossified comua which are not directly connected 
with the skull. A minute stjliform cartilage, which lies in 
close proximity with the portio dura, on the upper part of 
the posterior face of the quadrate bone, represents the styZo- 
hyal, or proximal end of the hyoideon arch. 

The pectoral arch has no clavicle, and the coracoid baa no 
distinct epicoracoidal element, nor any fontanelle. The 
carpus consists prosimally of two elongated and somewlul 
bonrglaas-abaped bones, articulated respectively with the 
radius and the ulna. The I'adial is the largei', and ie par- 
tially articulated with the ulna. Behind these, and directed 
transversely, lies another carved ossification, the ttpp«r 
concave face of which articulates with the idna. It ie onited 
with the latter bone on the one hand, and with the fifth 
metacarpal, on the other, by stiong ligaments, and represeuta 
a pisiform bone. Pistully, there lies on the ulnar side the 
so-called lentieviar bone, an oval ossicle interposed between 



THE CEOCODIUA. 25^ 

itlie nlnnr proximal cai-pul and the second, third, fourth 
and fifth metacarpals, the three hist of which it supporti 
■altogether. On the radial side, a disk of cartilage, which ' 

1 never becomes completely oaaifled, is connected hy ligament 
with the hitticulaTe, and is interposed between the radial 
;pvximal bone and the head of the metacarpal of the pollei. 
jJTrom the ulnar side of the head of this bone a cartUagi- 
jlona HgamentouB band pi'oeeeda, over the head of the 
,'flecond metacarpal, to the radial side of the leaticalare. 

The three radial digits are much etronger than the two 
ulnar, and the numbers of the phalanges are 2, ~ 
oounting from the radial to the ulnar side. 

The polvis (Fig. 78, C) possesHes large Qia, which are finuljj 
itmited with the expanded ends of the strong ribs of t 
I sacrum. The iechinm nnites with its fellow in 
ventral eymphyaia, and, with the ilium, forms almost the 
■ whole of the acetabulum. 

The pubes take hardly any share in the formation of the 
' btter cavity in the adult. Their asea are directed forwards 
and inwards, and they coalesce in the middle line; but as the 
inner, or median, moiety of each pubis remains tiartUaginoua,— 
or imperfectly ossified, the bones, in imperfectly prepa 
skeletons, appear as if they formed no symphysiB. 

The tarsus presents, proximally, an aatragalo-n 

bone and a calcaneum, which are less closely united than ii 

the Inzards. The latter bone has a. largo calcaneal process 

on its poateriorfaee, the OrocodUe being the only Sauropaid 

Tertebrate in which suchaprocess is developed (Pig. 78,0. Ca.) 

Two rounded distal tarsal bones, of which the fibular is 

ich the lai^r, lie between the calcaneum and the third. 

>urth, and rudimentary fifth, metatarsals. A thin plate of 

I is interposed between the distal end of the astra* -m 
icular and the second metatarsal, and unites v 
le head of the first metatajsal. 

le manus, the three, pre-oiial, clawed, digits a 
inger than the others. The fifth is represented only bjfi 
imperfect metatarsal. The uumhers of the phalanges a; 
4, 4, counting fi-om the tibial t« the fibular side. 



258 THE 

Tn the CTOcodilia the teeth are confmeJ to the premaxills. 
maxilla!, and dentiiry part of the mftndible. Thej are 
Bimple in Btrocture, have large pulp cavitiea, are lodged in 
distinct alTeoli, and are replaced hy others developed upon 
their inner sides. The development of the new tooth caases 
absorption of the inner wall of the base of the old one, and 
the replacing tooth thus comas to lie within the pulp cavity 
of ita'predecessor. The teeth vary much in shape, having 
either long, curved, and«ente, or short "Sja^btuse, or almost 
globular and straight; crowns. t^fiif^Ken they poasesa 
sharp anterior and posterior edges, which may be finely 
serrated. 

The Crocodilia are to be fonnd in the rivers of all con- 
tin<mts and the larger islands in the hotter parts of the 
world. None of the existing species are truly marine, 
though many of the extinct species were. They are first 
known to occur in strata of Triasaic age, and abound, 
under forms which differ but little from some of tbooe 
which now exist, in the Mesozoic and Cainozoic formatians. 

They may he divided into the following groups : — 

A. With proccBloua preEacral vertebrie, Bud posterior nam bonndeil 
tiolow bj the pterygoids. (All eslBlin^' Crocalilh, end tlie fosiil 
fomiB of CFetuceaus Bad Inter fonnalioDB, uro includeid in ttoi 
division.) 
a. The naEala enter into the farmstinn of the nasal Bperlucc. 

a. The bead sliort and broad. The teeth very uneqnal ; th« 
flrat nnd fonrth of the mandibles biting into piu of tbr 
upper jaw. The premaiillo-niBiillarj snture straight « 
Gunvei I'urwards. 'I'bc manilibular Bymphjsig qbt e^ 
tending beyond the fifth tooth, and (he tplenjal ^»- 
ment not entering into it. The cervical scutei dlsltMl 
from the tacgal. 
1. AWgalorida. 

Ailigator. Caiman. Jacare. 
ft. The head longer. The teeth unequal. The fi? 

bular tootUbiiinginlo a fossa; tie fonrth. into. ,,^ , 

01 the sidoof the upper jaw. The premBiillo-raaiilliiy 
suture straight or convex bnekwarda. The niandibukt 
EyuiphjsJB nipt cxlendinir beyond the eighth tooth, and 




TBE I 

b. The nasals are eiolurteiJ from (he Bitei 
head verj lonp; the teeih subtqual. 

fourth mondibular teelh bite into groovfis „ - - j 

upper j«w. Thopremajiillo maxillary suture nuutely angulalrf ' 
backwards. The mnndibnlar aymphyalB exteniJa to at leuD J 
the fourteenth lootli, and the Bplenials enter into it. , Tha \ 

3. Gapiallda. 

JihyncliOBucliia. Gttniala, 

B. With the pregacrai Tertebrgo amphicocloas (the anCeiior vertebnt I 

Ecimelimes opisthocofloua (?) ); and the postcrinr aareg bounded I 

by the palBlinea, tlia ptorygoida not being united below. (All. J 

these Croc-'-' -■- •" - -- ' ■ 

*. With the e: 



and pro 



4. Tel^ 



iriOa. 



Str^tofytondj/lut. Siayanalq;/!/. CalcsanntB 
I external narcs on the upper part of tlio base of th«| 



There ia e, laxge number of extinct Hcptilia which re-1 
Bemble the CrocoHiUa in the characters of their pre-Baorall 
vertebrffi, but differ from them, and resemble Latertilin J 
Chclonia, or Birda, in other reapecta. 

Theae are the IHcynodonUa, the Omithomxlida, and the J 
Pteronanria . 

VII. The DiCTHODOHTiA, — Bieyiiodon and Oittfenodowil 
are lacertiform fuiimala. BOinetimes of large size, with 1 
crocodilian vertebwe, four or five of which are ankyloaed'l 
together to form a strong aacrum. The akull ia 
and lacertilian in most of ita charactera ; but the jaws tiFaiJ 
like those of the Chelmda, and were doubtless cased in 
homy beak. Nevertheleas, ino?t of the species poBseas two .1 
great taska, which grow from peiBiatent pulpa, lodged ii 
a. deep alveolus of either maxilla. The limba appear to | 
have been snbeqnal and massive, with short and stout feet. 
The scapula and coi-acoid are simple and eijianded, and i 
there scemH to have been no clavicle. The pelvia is vei^ 
strong, with widely expanded ilia, ischia, and pubes. The 
two latter meet in a median ventral sympliyais, and th« 
pabie and ischiuin of each side meet and obliterate tiie 



THE OENITHOSCELIDA. 26 

ImvB Leon bo murh raised. The Crooodile'a limit is purposely repn 
sented in an tinnatuiBl positioti. In natare, Ihe feoiur woald b 
turned nut nesrlj' aC riglil angles to the middle TCrticnl plane iif tb 
body, and the metatanua would be liorlzontHl. The letters nro th 
same thronghout, //, ilium ; is, iBohium; Pi, pubis; a, anieriot pec 
eeae, b, poslerior process, of the ilium ; Tr, inner trochanter of ih 
femur ; T. tibia; F., fibula ; As, astragalus ; Co, calcaneam. I., II 
7//., /r., the digitB. 

Remains of these Reptiles taye iiitberto been foniid only 1 
in stiuta, which prohahlj belong to the Triasaic formation, 
in India and South Africa, and the Ural motmtains. 

Tin. The OenithosceIiIDA. — The very remaj-kable ex- ' 

f tinct reptiles which constitute this group, present a. larg* ■ 

seriea of modifications intermediate in Htriicture between \ 

existing Meptilia and Avis. 

Thia transitional character of the Omithoscelidan ekeleton | 
is most narked in the pelvis and hind limbs. 

If the pelvis of any existing reptile be compared with J 
that of any existing bird, the following points of diSerenoB J 
will be obeerved :— 

1. In the reptile (Pig. 78, C.), the ilium is not prolonged 
in front of the acetabulum ; and the acetabulum is eithei" 
wholly closed by bone, or presents only a moderate-sized 
fontaneUe, as in the Crocodilia. 

In the bird (Fig. "8, A,), the iliiun is greatly prolonged 

in front of the aeetabnlum, and the roof of the acatabulaS', 

cavity is a wide arch, the inner wall of that cavity re-, 

f jnaining membranous. The anterior pier of the arch, o* 

B prs- acetabular process, extends further downwards thant. 

Kilhe posterior pier, or post-aceta,bular process. 

But, in all the Oi-nUhoeeelida, the ilium extends far ia 
I ^TJnt of the acetabnlum., and furnishes only a widely arched 
iMiof to that cavity, as in birds. It retains a reptiliai 
■ fiharacter in the further proportional extension of the post- 
lacetabular process downwards (Fig. 78, B.). 

2. The iacJiium, in the reptUe (Fig. 78, G.) is a moderately 
■Slongated bone, which becomes connected with the pubis in 
1 the acetabulum, and extends downwai'ds, inwards, and Bomaj 



i 




262 THE ANATOMY OF YESTEBSATED ASTIMAIiS. 

what backwards, to unite with its fellow in a median ventral 
symphysis. The obturator space is not interrupted by 
any forward process of the outer and anterior half of the 
ischium. 

In all birds (Fig. 78, A.), the ischium is elongated and 
inclined backwards, the backward direction being least 
marked in Apteryx, and most in Bhea. The ischia never 
come together directly in a median ventral symphysis, 
though they unite dorsaUy in lihea. The anterior edge of 
the external, or acetabular, half of the ischium very gene- 
rally sends off a process which unites with the pubis, thus 
dividing the obturator space. 

In all the Ornithoscelida (Fig. 78, B.), in which I have been 
able to identify the bone ( lliecodontosaunis, Teratosaurus, 
Megahsaurus, Iguanodon, Stenopelyx, Hadrosaurus, HypsUo- 
phodon)y the ischium is greatly elongated. In Igtianodon it 
has the obturator process characteristic of the same bone in 
Birds; and I imagine that the game process is seen in 
Compsognathus, In Hypsilophodon there can be no mistake 
about the matter, and the remarkable slendemess and pro- 
longation of the ischium give it a wonderfully ornithic 
character. In Iguanodon the slendemess and prolongation 
are even t;arried beyond what is to be seen in Birds. I am 
disposed to think, however, that, as was certainly the case 
in H^ailophodon, the ischia united in a median ventral 
symphysis in all the Ornithoscelida, 

3. In all reptiles the pubis is inclined forwards, as well as 
downwards, towards the ventral median line. In all, except 
the Crocodile, it takes a considerable share in the formation 
of the acetabulum ; and the ossified pubis unites directly 
with its fellow in the middle line. 

The pubes of Corrvpsognathus are, unfortunately, obscured 
by the femora. They seem to have been very slender ; and 
to have been directed forwards and downwards, like those 
of lizards. Some lizards, in fact, have pubes which, if the 
animal were fossilized in the same position as Compsogna" 
thuBy would be very similar in form and direction. HypsUo- 
j}hodo7i, however, affords unequivocal e\AAgn.c«& ot ^l\xrthftr 



THE OSNITHOSCEIilDA. 263 

step towards tlie bird. The pubes are not only as slender 
and elongated as in the most typical bird, but they are 
directed downwards and backwards parallel with the ischia, 
thus leaving only a very narrow and elongated obturator 
foramen, which is divided by the obturator process. 

It remains to be seen how far the hypsilophodont modi- 
fication extended among the Omithoscelida. The remains 
of Compsognathus and of Stenopelyx tend to shew that it was 
by no means universal. 

As to the hind limb, in existing reptiles : — 

1. The proximal end of the tibia has but a very small, or 
quite rudimentary, cnemial crest, and it presents no ridge 
for the fibula on its outer side. 

2. The fiattened sides of the distal end of the tibia look, 
the one directly forwards, or forwards and inwards; and 
the other backwards, or backwards and outwai'ds. And 
when the posterior edges of the two condyles of the 
proximal end of the tibia rest on a fiat surface which looks 
forwards, the long axis of the distal end is eithoj^early 
parallel with that surface, or is inclined obliquely JRtai in 
front and without, backwards and inwards. 

3. There is no depression on the anterior face of the^tibia 
for the reception of an ascending process of the astragalus. 

4. The distal end of the fibula is as large as, or larger 
than, the proximal end, and articidates largely with a facet 
on the outer part of the astragalus. 

5. The astragalus is not depressed and fiattened from 
above downwards, nor does it send a process upwards in 
front of the tibia. 

6. The astragalus remains quite free from the tibia. 

In all these respects the leg of any existing bird (see 
Fig. 78), is very strikingly contrasted with that of the reptile. 

1. The proximal end of the tibia is produced forwards and 
outwards into an enormous cnemial crest, in all walking and 
swimming birds (Fig. 78, A.) ; and, on the outer side, there 
is a strong ridge for the fibula. 

2. When the posterior edges of the condyles ol ^^ \r5c\sv» 
reet mpon a flat surface, the one ^at iaAie oi >iJSife ^^\fi^ ea.^ 



•2U 1 

of the bone looks otttwarils as well aa forwards, and tte 
otlier inwards us well its backwards. Farther, the long axis 
of the diataJ end is inclined, at an. angle of 45° to the flat 
aurface, from within and in front, backwarde and outwarda, 
thua exactly reversing the direction in tlie reptile. 

3. There is a deep longitudinal depression on the anterior 
fitce of the distal end of the tibia, which receives anaecend- 
ing process of the astragalus. 

4. The distal end of the fibula is a mere style, and does 
not articulate with the astragaius. 

5. The astragalus is a much- depressed bone, with a con- 
cave proximal, and a convei, pulley-like, distal, surface. A 
process ascends from its front margin in the groove on tiie 
front face of the tibia. This process is comparatively short, 
and perforated by two canals for the tibinlig rintieuB and 
extensor commutiw, in the Fowl ; while in the Ostrich and 
Emeu it is extremely long and not so perforated. 

6. The astragalus becomes ankylosed with the libia 
(though it remains distinct for a long time in the Ostricli 
und Bkea, and in some breeds of fowls}. 

In the Ornitkosedida : — 

1. There is a great cnemial crest andaridgefor the fibula. 

2. The disposition of the distal end of the tibia is literally 
that observed in the Bird. 

3. There is a fossa for the reception of the ascending pro- 
cess of the astragalus. 

4. The distal end of the fibula is much smaller than the 
proximal, though not so slender as in Ave8. 

5. The astragalus is altogether similar to that of a bird, 
with a short ascending prouesB. 

6. The astragalus appears to have remained distinct from 
the tibia throughout life iu I^nanodoii,, M^gaiomitna, and 
many other genera ; but it aeema to have become ankyloeed 
in Coiiip$agiMtkM, Ornithotarens, and Easlceloeaiinu. 

The reptiles bdon^ng to this group are for the most part 
of very large size, and some of them, aa the Iguanodon, are 
among the lar'gost of known terrestrial animals. They 



THE OBNITHOaCELIDA. 265 i 

occw througliout the whole range of the Mesozoic form*- i 
tionB, being vepreaijntad by Tliecodontosaurus, Podeosai*- I 
rus, Teratogaivrvs, Plakeosaurua, and other genera i 
Trias; bj Scelid^iMwarw in the Lias: by Megalog, 
Poikiliipleuron, EusJteloaa'aras, HyUeosaarus, PolaeaiUhiu, i 
AeanthophoUe, Iffiumodon, MadrosaToiiB, Traehodon, aad'| 
XiOelapB in the middle iind upper Meaozoic strata. 
> There ia no evidenos that MegaUnaurug, or lyuanod 
lifosaeBsed any dermal armour; but several genera, (e.i 
'Scelidosaimts, SyTiBQ«awtta, and AcatiihophoUa) had o 
i^rmal scutes, sometimea produced into prodigious spines. ■ 

The faces of the centra of the vertebrse are slightly I 
vMnphiciBlous, or neai'ly Hat ; but those of the anterior dorsal J 
■nd cervical regions aeem, in some cases, to have been opifl- J 
thocraloua. The aacrom aeema to have consisted of at ■ 
fewest four vertebras, vrhich in aome {Bcelidosamrnsj are cro-] 
oodilian, in others {Mngaloeaunis) take on a somewhat o 
jiithic character. The caudat region had many and lonffV 
:'»ertehr». between which the chevron bones are attached 
The rami of the chevron bones have tlieir vertebral e 
■united by bone. 

The thoracic vertebral riba are very strong ; but tkcJ 
sternal ribs and sternum are nnknown. However, there iq 
some reason to think that the Btemum waa broad and e 

► panded. Abdominal dermal ribs are developed in son 
Bpeciea, if not in all. 
The alructure of the atull aeema to have been interme- 
diate, in m.any reapecta, between the crocodilian and the 
lacertilian types. In Igvanodon and Hypsilopliodon, the 
extremities of the premaiillEe appear to have been edentn- 
lous and beak-like ; and the symphysis of the miindibie is 
excavated to receive the beak, almost as in the mandible of 
a Parrot. 

The teeth vary extremely, from the sharp, recurved, ser- | 
rated fangs of Megahmurus, to the broad grinders, wearing 
.down by mutual attrition, of Tgnanodon. Their mode of 
iplantation varies, but they are not ankylosed to the jaws. 
The scapula is rerticaUy elongated, narrow! and devoid of 



aaj ELoromial process ; the coracoid roimded and without 
fontanelles or procesaes. 

No OmithoacelidBJi is biiowii to have possessed a clavicle. , 

The foi'e-Umb is Bhorter, wid often nmoh ehorter, thuu j 
the hind-limb. The Btmctnre of the manus is not certainlj { 
known. 

The femur usubJIj baa b, strong inner trochanter ; and its 
distal end is partiouJarly bird-like, in the development of a 
strong ridge, which plays between the tibia and the fibnia. I 

The nieta.titrsak are elongated, and fit together in ancb a i 
way that tbey can hardly, if at aO, move on one another. 
The inner and out«r digits are either shorter than the rest, 
or quite mdimentary ; and the third digit is the longest, as 
in birds in general. 

The Oraithoscelida are divisible into two anb-ordera, the I 
Dinoaav^a and the Compsognatka. The type of the Iatt«r I 
division ia the wonderfid little extinct reptile, Compsogna- 
tiau, which differs from the Diaoaavria in the great length 
of the centra of the cervical vertebne, and in the femur 
being shorter than the tibia. It has a, light bird-lilce head 
(provided with numerons teeth), a very long neck, amall 
anterior limbs, and very long posti^rior limbs. The astia- 
galns appears to have been ankyloeed with the tibia, as in 
birds. A single specimen only of this reptile has been 
obtained, in the Solenhofen slates. 

IX. The Ptbkosauma.— The flying Eeptilea. which be- 
long to this group, and are commonly known aa Ptero- 
dactyls, are, and long have been, extinct, their remains 
occurring only in Uesozoic rocks, from the Lias to the 
Chalk inclusively. 

They ai'o all remarkable for 'their proportionally long 
heads and necks, and for the great size of the ajihenor 
limb, the ulnar fiuger of which, enormously elongated and 
devoid of a claw, appears to have snpported the outer edge 
of an expansion of the integument, like the patagium of a 
Eat (Fig. 79). 

The vertebi'al column is distinctly divided m\o cervioal^ 



THE PTEK03ACBU. 




left pre-pubio bone: on the right side tk 
■he ilium it exposed. 

e ankjloaed together, at least in the cretaceons 



The other cervical Tert«bne, apparently not b 



OP VERTEBKATED ANIMAXa. 

or aeven in !iimil>er. have low, or obsolete, Bpinous proceaees ; 
and, like the vertebriE of the rest of the Bpine, are procoelons, 
and huve the nenro-central suture obliterated. The esMb- 
ence of cervical ribs is doubtful. From fourteen to sixteen 
vertebne intervene between the cervical and tbe sacral 
regions ; and not more than one or two of the hindermoBt 
of them, if any, are devoid of riba. The number of vertebrsB 
antjlosed together to form the sacrum, is not fewer than 
three, nor more than six. 

The tail ia very short in Fterodaetijlue, and, in this genua, 
all the vertebrffl are moveable upon one another; but, jn 
Bhmiifihorhynchtts, it ia extremely long, &nd the vertebra are 
immoveably fixed by what appear to bo ossified ligamentoni 

The vertebral ribs are slender, and the anterior ones, at 
any rate, have distinct capitula and tubercula. There sat 
ossified Btemal riba, and splint-Uke abdominal ribs. The 
atemnm is broad, and, imlike that of other Repiilia, is veiy 
completely ossified, and bears a strong m.edian creat o 
anterior part of its ventral surface. So median posterior 
prolongation has been observed in connection with it. 

The brain case ia more roimded and bird-like than in t 
other Beptilia, and, in many other respects, the slciill e 
proachea that of birds. Thus, tbe occipital condyle ia 
the base of the skull, not on its posterior face ; the cranial 
bones ankylosed very early; the orbits are very large, and the 
external nares are situated close to them. The premaxUlB 
are very large, the maiilliB slender, and the dentary pietKs 
of the mandible are fused together into one bony mass, witb- 
oot any trace of a symphysial suture. 

The resemblance to birds ia still further increased, is 
some species, by the preaence of wide lachrynio-nasal fosBS 
between the orbits and the nasal cavitiea, and by the pro- 
longation of the extremities of the premaxillte and of tbe 
aymphysial part of the mandible into sharp, beak-like pro- 
oeases, which appear to have been covered with homy 
aheatha. But the reptilian type is kept up by the x>T%8enoe 
of a distinct postfroutal, which unites with the squsLittoad^ 



i PTBKOSAUKIA. 



sW^^ 



I 



and thnB gives rise to a eupra -temporal fossa. The post- 
^Mntal and the jugol unite behind the orhit, in Lacd'tilian. 
'jashion; ajid Loth the upper and the lower jawa contain 
The Bclerotic ia etipported hj a ring of bonea, as in 
ly other Sauropsida. 

The Bcapula and the eoracoid are wholly unlike these 
stmcturea ia any other Baiiropstda, hut are eitremely 
BimUar to the same parts in birds, and indeed to the 
ahoulder girdle of the leas reptihan CarinatcE. The scapula 
is slender aud blade-Uke, axid its long axis is inclined, at 
lesa thai a right angle, to that of the CMruooid. The 
glenoidal surface is cylindroidal, concave from ahove 
wards, conves from side to side. The eoracoid, elongated 
and comparatively nan-ow, ia devoid of fontacelle, epico^ 
racoid, or procoracoid. 

No trace of any clavicle has been discovered. 

The hnmema has a great deltoid ridge or process. Th»1 
radios and ulna are equal in size and separate. There 
four distinct metacarpal bones, that on the ulnar side being 
very much stronger, though not longer, than the others. 
Another stjliforro bone attached to the carpus doea not 
appear to have belonged to the metacarpal acrioa. The 
radial metacarpal bears two phalanges ; the second, three 
the third, four, so that these represent the poUeK 
the succeeding digits of the Lizard's nianus. The 
minal phalanx of each of these digits is atrong 
curved, and was doubtleae enaheathed in a homy elai 
The fourth, like the corresponding digit in the Crocodile;" 
baa four phalanges, the last of which ia straight and bears 
^laiL But theee phalanges are enormously elongated and of 
p'eat relative strength. A strong process projects from the 
^rsal side of the proximal end of the firat phalanx, and 
'doubtless gave attachment to the tendon of a correspond- 

j'ly powerfid extenBor muscle. The ai'ticnlar surface 
lelow and behind it, is concave, and plays ove 
[distal pulley of the fourth metacarpal. 

The pelvis is remarkably small. The ilia are elongal 
lea, produced both anteriorly and posteriorly, aa in . 



'g 
at 

and^^^J 



but the rest of the pelyis is not at all ornithic. The flat 
and broad isohia appear to bo united with the pubes into 
wide bony plates, which pasa, a.t right angles with the ilia, 
to their median ventral Bjmphyaia. A large Hpatnlate bone 
articulatea witii each pubis near the ajmphjsis, aud seems 
to be an exaggeration of the pre-pubio process of LacertUia 
Bind Ckehnia, Or it may be (though I do not think thia 
veiy probable) that the broad flat plates correspond almoflt 
altogether to the ischia, and that the spatulate oaaifiuationa 
are the pubeaj in whiuh case the structure of the pelvis 
woidd be a sort of eitreme csaggeration. of that observed in 
the Crocodilia. 

The hind limb ia amall oompared with the fore limb. The 
libula ia imperfect, and appears to coalesce with the tibia at 
its diatal end. The atructure of the taraua requires fur- 
ther elucidation. In some Pteroaauria there seem to beonly 
four digita, with, perhaps, a ruditnent of a fifth, in the pes; 
but others, such as BkamphorhyncfiuB Gemmittgi, have five 
digits ia the foot. Where there are only four, each digit ia 
terminated bj a curved and pointed ungual phalani, and 
the number of the phalanges from the tibial to the fibular 
aide ia % 3, 4, 5. Those digits, therefore, are the hallux, and 
the three which immediately follow it ; and the radimentaij 
digit ia the fifth. 

The long bones of the Plerosauria have thin walls, in- 
closing a large cavity, which appears to have contained air, 
as ia many birds j and pneumatic foramina are visible on 
the aides of the vei-tebrte. 

The remains of more than twenty speciea of Pleroaauria 
have been discovered. Some of them are exquisitely preserved 
in the fine matrix of the lithographic stone of Solenhofe a. 

They are thus grouped into genera ; — 

A. With two joints in the ulnar digit of the 

Omithoplcraa. 

B. With four joints in the uinnr digit. 

usuBlly longer Ihnn half the length of the 
Pie ■ - ■ 




THE FTKBOBAU^IA- 271 

b. The extremities of dx ja^ra produced imlo moclikss beaks 
|nt>bably ensheathed in be m. !!:« tail Texy kmp. The 
metacarpus shcxter than balf the lei^thof the ante> 
brachium. 
a. All the mandibular teeth similar. 



b. The poBteiior teeth for the most part very short. 
The anterior long. 



I am much inclined to suspect tliat tlie fossil upon which 
the genus Omithopterus has been founded, appertains to a 
true Bird. 



272 THS ASAT03CT OF VERTBBRATED 



CHAPTEB TI. 






THE CIASSIFICATlOn AJTD TSE OSTEOLOGY OF BmDB. 

The class Aves — Though tliis clasB contains a, great 
DDmber of specific forms, the structural modifications which 
they present are of comparatiTely little importance; i 
two birds which can be selected differing from one another 
far less than the extreme types of the Laeertilia. and hardly 
more than the extreme forms of the Chelonia, do. Hence the 
characters by which the following groups are separated 
appear almost insigm£cant when compared with those hj 
which the diviaions of the Bej/tUia are indicated. 
A. The mctuarpslg not snkjlosed tosether. The tul longer 



B. Thema'BCBrpatBBDkyloBed together. The tailconsiderablyrt 



he wing with a nidimeiilarj', or very short, hna 
and with not more than one uDgnal pbalanz. 

2. Aptf^rygidx (The Kiwi.). 
0. No hallux. 

3. Dhomilhld-e (The SIobb). 



b. The win); with a loi 
u. The ischia u 



ting immediately benealli tlis 



' The keel ia rudimontary in the lingular Parroc S, 



CLAasIFICATION OP BIRDS. 





d behind, an 
the palnin 


din 
es, 


orpofline betwee 
ad (he baaisph 


T. Tinanu 


««■/,*« (Th 


Ti 


amouB). 


rhe vomer narrow behind:! 


;^se;l£ 



1. The maxlllo-palntineB free." 



i'ft. 



C/iaradrftiinor/iAo; ( 
Cecomarphie (The 
f^AcnMconoRiftffi (The Penguins). 
Uerimamorpkc (The Cranes), 
rarjiii'imofjjAfe (The Uemipuda). 
Alictonmiorp/iie Clbe Fowls). 
Pleroclomorplia (The SniiU-BrouBe). 
FtriHtromorpluHne PieeoHs). 
Heteromorpluc (The Uoaiin). 
ii. The vamer truncated lu fraot. 

Coracoinurplue (The FsBaerinea). 
Ci/pieinaorphicJ'riie Bwifta). 
CekomorpfuB {the Woodpookers). 
It. The mBxillo-pftlalinDB anited. 



•rey). 

a). 

3B, Klng- 



]. Aftomo^ha (The Birds d1 



!. Coarygomtirpb 

i. Cieiu^jdia frhe'Anserine Birdt). 
1. AmpliinaTphre (The Eluniinpiea). 
i. Pnlvsmmrpha (The Storkis). 
i. Dj/ipimimiiphie (The CormomT 



i)-t 



• With the BKaeption of Didiolophai and some species of Crux. 
T Tne subjoined Table, which shows with which of the above groups 
he nid orders of Sirds eorrespond, maj' be ueelul to the student :- 



irpha, Coccj/i/oiuor 

(in perl). 




27i THE ANATOMY OP VEHTEBaATED ANIMALS. 

The enoskeleton of Birds coneiata almoet entirely of epi- 
dermic atructurea in tiie form of homy abeatlis, Bcalea, 
plates, or feathers. No bird posaeaseB deiTual oesificationB, 
unless the spui-s whicli are developed upon the lege and 
wings of aome apecies may ba regarded as such. 

The feathera are of Tajious kinda. Thoae whioli exMbit 
the must complicated atructure are called peniUE, or coniow 
featheri, because they lie on the aurface and determine \ha 
contour of the body. In every penna the following parta 
are to be distinguished : — 1. A main stem {eca/pufi) foradng 
the axis of the feather, and divided iato a proximal hollow 
cylinder, partly embedded in a aao of the derra, called the 
ealamua, or quill ; and a diatal 'Hexilluifii, or vane, conaisting 
of a fonr-aided solid shaft, the racMa. which extends to the 
extremity of the feather, and beara a number of lateral pro- 
ceasea, the barba. The calamns has an inferior apiertnre 
(wmfciiMflMin/erior), into which the vascular pulp penetratea; 
and a. superior apeiiure (wnbilisas superior), situated on the 
under surface of the feather at the junction of the calamus 
with the soapua. The barba ai-e nan'ow platea, tapering to 
points at their free ends, and attached by their bases on 
each aide of the rachis. The edges of theae barba are 
directed upwards and downwards, when the vtaeUlunt of 
the feather is horizontal. The interstices between the 
barbs are filled up by the barbuks ; pointed proceeaeB, wliich 
stand iu the same relation to the barbs, as the barbs do 
to the rachis. The barboles themaelvea may be laterally 
serrated and terminated by little hooks, which interlock wiUi 
the hooka of the oppoaed barbulea. In very many birds 
each qoill bears two vexilla ; the aecond, called the aflerthafi 
{liijporach.it], being attached on the under aide of the first 



IV.—GAiajvx (niUi CaiMasxi^Atrti 



AmphiiaOTpha, Pcla 
, = Ctconiorphit. Sphaiuc 






TH& FEA'DHSKS OP SIBDS. 27^^ 

close to the anperior mnbilicue. The afterstait is generally 
mucli smaller tlian tho eljiof Texillum ; but in some birds, i 
as the Caauai'idiE, the two are of equal size, or nearly ao. ] 
Muscles pass from the adjacent integument to the feather 1 
aac, and by their contraction erect the feather. The other 
kinds of feathen differ from, the pennte, in having the barbs I 
Bof t and free from one another, when they constitute penno- , 
pla-mai, or plu/muke (down), according as the scapns is much ! 
or little developed. When the scapua is very long, and the 
Texillum very amall or rudimentary, tlie feather is termed 
afilopbima. 

The contour feathers are disti-ihuted evenly over the body 
only in a few birda, as the Batitw, the PenguinB, and some 
! others. Generally, th.e pennte are arranged in definitely 
I circumscribed patches or bands, between which the intega- 
f meat is either bare, or covered only with down. These 
' series of eontoni- feathers are termed pterylce, and their 
interspaces, apleria. 

In some birds, eueh as the Herons, plumula of a peonliarJ 
kind, the summits of which break off into a fine dust, O 
powder, as fast as they are formed, are developed upon J 
certain portions of the integument, which are termed powdBr] 
doum, patchsi. 

The integument of birds is, for the most part, devoid of 
glands; but many birds hare a peculiar sebaceous gland 
developed in the integument which covers the coccyx. This 
vropygial gland secretes an oily iluid, which the bird 

i spreads over its feathers by the operation of " preening."- 
^e eicretion passes out by one or two apertures, commonljij 
situated upon an elevation, which may or may not 1 
provided with a special circlet of feathers. 

In various birds {e.g., the Turkey) the integument about I 
the head and neck develops highly vascular and somotimea 
erectile processes (oojiiAs, viaUhs). 



The spinal colmnn of birds contains numerous and well 
ossified vertebra, a considerable number of which (m 
than six) are anlQ'losed together to form a sacmm. Of 



276 THE ANATOMY OP TEBTEBEATED A 

the vertebne "wliich enter into the coin position of thie com- 
pks bone, however, not more than from three to five can 
be regarded aa the homologiiea of the eaeral verfcebriB of a 
Orocodilian or La^ertilian reptile. The rest are borrowed, in 
front, from the lumbar and dorsal regions ; behind, from the 
taQ. The cervical region of the epine is always long, and 
ita rertebrffi, which are never fewer than eight, and may 
be aa many as twenty-three, are, for the moat pai"t, large ir 
proportion to thoae of the reat of the body. 

I'he atlas is a relatively amall, ring-like, bone; and the 
transvei'ee ligament may become ossified and divide i 
aperture into two — aa upper, for the apinal cord, and a 
lower, for the odontoid proceaa of the aiia vertebra. The 
OS odontoidewm ia alwaya ankyloaed with the aecond Ter> 
tebra, and constitutes a peg-like odontoid proceea. 

The spines of the succeeding cervical vertebra) are often 
obsolete, and are never very prominent in the middle region 
of the neck. The anterior faces of their elongated vertebral 
centra are cylindroidal, slightly excavated from above down- 
warda, and conves; from aide to aide; while the poeterior 
faoes are conves from above downwards, and concave from 
aide to side. Hence, in vertical section, the centra appear 
procoelous ; in horii^ontat section, opiathoeceloua ; ajid this 
fltructure ia exceedingly charaGteriatic of birda. The n 
surfaces of the centra frequently give off median inferior 
processes. In the Satiia:, it is obvious that the cervical 
vertehne have ahoi-t transverse processes and riba, disposed 
very much aainthe Crocodilia. For, in young birds, the ante- 
rior end of the lateral face of each vei'tebra bears two umall 
proceases, on upper and a lower ; and the expanded head of 
a styliform rib ia articulated with these by two facets which 
represent the capituluia and the tuberculum. "With i 
the cervical ribs may become completely ankylosed ; i 
then they appear like transverse processes, perforated at Uie 
baae by a canal, which, as in the OrocodUia. contains the 
vertebral artery and vein, and the main trunk of the sympa- 
thetic nerve. The cervical ribs and transverse proeease* 
Ar« similarly disposed in very young CaruuUiEj but is ^ 



THE VEETEBKJE IN BIRDS. 277'^ 

birds their form frequently becomes mucli modified ii 
adult ; and they develope prulongatioiiB, which oitend down-'' I 
words and tuwurds, and protect the cnrotid artery ( 
arteries. 

The neoral arches have well derelopeiJ pre- and poat- 
zygapophyaea. The riba of one or two of the posterior 
cervical vertehrie become elongated and freely moveable ia 
the CwincUis, ae in the BatUw. 

The first dorsal vertebra is defined as such, by the u: 
of its ribs with the sternum by meane of a eternal rib;., 
■which not only, aa in the Crocodilia, becumes articulatei 
■with the veiiebral rib, hut ia converted into complete bont 
and ie connected by a true articidiLtion with the mi 
the Etemum. 
I The number of the dorsul vertelntB (reckoning under that 
I head all the vertebra, after the first doraal, which i 

distinct ribs, whether they ba fixed or free) varies. Thfl^ 
centm. of the dorsal vertehne either posseSH cylindroidal 
articular faces, like those of the neck, as is usually the 
case ; or, more or fewer of them may have these faces 
spheroidal, as in the Feugtuns. In this cose, the con' 
face is anterior, the concave, posterior. They may, or n 
not, develope inferior median procesaes. Theyusnally p 
aess well marked spinous processes. Sometimes they a 
slightly moveable upon one another; sometimes they be^ 
come ankylosed together into a solid mass. 

It is characteristic of the dorsal vertebra of Bii'ds thatl 
the posterior, no less than the anterior, vartebi-a) present ft.fl 
facet, or small process, on the body, or the lower part of tha 
arch, of the vei'tebra for the oapitulum of the rib, while 
the upper part of the neural arch gives off a more elongated 
transverse process for the tuhercnlum. Thus the trana- 
vei-se processes of all the dorsal vertehne of a bird resemble 
those of the two anterior dorsals of a crocodile, and no 
part of the vertebral column of a bird presents transverse 
processes with a step for head of the rib, like those of t' 
great majority of the vertehne' of Crocodilia, THnoaaun 
ZHcynodontia, and Pleroaauria. 



LSlB THE ANATOMY OF VERTEBEATED 

The diBcriminaticm of the proper lumbar, aacral and 
anterior caudal vertebrffi, in the ant jlosed mass which consti- 
tutes the so-called '■ aacrum " of a bii'd, ia a matter of consider- 







ahle difficulty. The general arrangement is as follows^ 
The most anterior limibar vertebra has a broad transTerae 
pi*ocesB, which corresponds in form and position with the 
tubercular tranaverae procesa of the last dorsal. In tie 
Bueceeding lumbar vertebra} this process extends down- 
wards; and, in the hindermost, it is continued from the 
centrum, as well as from the arch of the vertebra, and 
forms a broad mass which abuts against the Uium.* Thia 
process might well be taken for a sacral rib, and its ver- 
tebra for the proper aacral vertebra. But, in the first 
place, I find no distinct osaification in it; and, secondlj, 
the nerves which issue from the iiitervert«bral foramina ix 
front of and behind this vertebra enter into the lumbar 
plems, wliich gives origin to the crural and obturator ner 
and not into the sacral pleins, which is the product of the 
nerves which issue from the intervertebral foramina of the 
proper sacral vertebne in other Veiiehraia. Behind the last 
lumbar vertebra follow, at moat, five vertebrw, which hflTe 
no ribs, but their arches give oif horizontal, lum pilar, trs 
vei-se proceasea, which imite with the Uia. The nerves which 
issue fi-om the intervertebral foramina of these vertebna 

• It would be more proper lo cess, like other prucesses, exUli 

nay thai osaiflcsliou cxlendB inlo befurc the centrum is diffe 

It from tbe centiuin ts ncll sa tialeii from the lucli by oi 

(rom the neuml arch. The pro- cation. 



THE VEKTEBB^ IN BIEDB. 279 

unite to form the Ha*;ral plexue, whence the great aciatic 
nerve ia given, off; a,nd I take them to be the homologuea 
of the Hacral vertehras of Beptilia. The deep f oaste betvreen 
the ceutra of these vertebre, their traoieverse processes, and 
the ilia, are occupied by the middle lobcB of the kidneys. 

If theae be the true aacrol vertehne, it followa that their" 
encceasoTS are anterior caudal. They have expanded upper 
tranaverae proceeaea, like the proper sacral vertebne ; but. 
in addition, three or four of the most anterior of these ver- 
tebra poaaesa riba which, like the proper aacral riba of rep- 
tiles, are auturally united, or ankylosed, prosimaUy, with, 
both the neural archea and the centra of their vertehne, 
while, diatally. they expand and ahut againat the ilium. The 
ankyloeed caudal Tertebi-ffl may he diatingniahed aa uro- 
sacral. The caudal Tertebne which succeed theae may be- 
numerous and all distinct from one another, ae in Archceop- 
teryx and Rkea ; but, more generally, only the anterior caudal ' 
vertebra are dietinct and moveable, the test being ankyloaed 
into a ploughshare- ahaped bone, orpygostyle, which eupporta 
the tail feathers and the uropygiol gland, and aometim.es, 
in the Woodpeckers and many other birds, eipands below 
into a broad polygonal disc. 

The centra o£ the moveable presacral vertebrie of Bi 
are connected together by fibro- cartilaginous rings, whi 
extend from the cii-comference of one to that of the ni 
Each ring ia continued inwarda into a disc with fi 
anterior and posterior facea — the meniscus. The 
thins towarda ita centre, which is alwaya perforated. The' 
aynovial apace between any two centra ia, therefore, divided 
by the meniscna, into two very narrow chambera, which com- 
municate by the aperture of the meniscus. Sometimes the 
I meniscua is reduced to a rudiment ; while, in other cases, it 
h may be united, more or leas extensively, with the faces 
I of the centra of the vertebrsE. In the caudal region, the 
■ union is complete and the meniscus altogether reaemhlea an 
^h ordinary intervei'tebral cartilage. 

^B, A ligament traveraes the centre of the aperture in the 
^K meniscus ; and, in the chick, contains the intervertebral por- 



4 





280 THE ANATOMT OF TEKTEBBA.TED 

titm of the notochoi-d. Ah Jiiger* has shewn, it i 
Lomologue of the odontoid ligament in the cranio-spinal 
articulation ; and of the pnlpy central part of the interrer- 
tebral fihro-cartUagea in Mammalia. 

All the vertehral ribs in the doraal region, except, per- 
haps, the very last free riba, have widely separated capitula 
and tnbercula. More or fewer have well ossified nncinate 
procesaea attached to their posterior margins, as in the 
Oroeodilia. The vertebral ribs ore completely oBsified up to 
their junction with the eternal ribs. The Btemnm in birds, 
ie a brood plate of cartilage, which is always more or less 
completely replaced in the adult by membrane bone.+ It 
begins to oasiEj by, at fewest, two centres, one on each aide, 
OA in the BiUiiw. In the Carinalm it nsually begins to 
OBBify by five centres, of which one is median for the keel, 
and two are in pairs, for the lateral parts of the st«niQm. 
Thus the stemnm of a chicken is at onetime separable into 
five distinct bones, of which the central keel-bearing oaai- 
fication (r. to m.x. in Fig. 81| is termed the lophosteon, the 
ajitero-lateral piece which articulates with the ribe, pleit- 
roaieon [pi. o.}, and the posterolateral bifiirca.ted piece, met- 
osteon. 

Though the Htemum, in most birds, seema to differ very 
much in form from that of the ifepiiiia, it is rhomboidal in 
the Caeuarida, where it differs from the reptilian stemnm 
chiefly in the greater proportional length of its posterior 
aides, the absence of median backward prolongations, and 
the convexity of ita ventral aurface. Butinotherbirda, and 
notably in many Carinatte, the antero-lateral edges, which 
are grooved to receive the coracoida, form a much more 
open angle than in the Reptilia, while the poatero-lateral 
edges become parallel, or diverge ; and a wide, straight or 
conven, transverse edge takes the place of the posterior 
angle. Two, or four, membranous fontanelles may remain 

* " Dag WirbelkArpergelenk Bternum, like Ihoee further on 
dcr VBgel." Siliungaberiobte trmchiuff the skull, do not Kppir 
dor Wiener Akademie, ISas. to Arharpitni, in which all these 

I These statemenls respecting purls are unkoowu or imperfectlj 
the vectobrul column, ribs, sod *' 




in the posterior moiety of the Bteranm when ossificatioH. I 
takes place, and give rise to aa manj holes, or deep notclias,. T 
separating slender proeessea in the 1I17 skeleton. All tLeea I 
oorreHpoud with so man j diyiaions of the xiphoid prooeaK I 
of the Bternum in Mmii'inalia, and hence are called middle t 




Fig. 81.— Front and eide views of the gtemum 1 
ormanulirium ; c. p.,coatiitpT<icaa; pi. o..pli 
the letter goea to tile point of jnnction between tlie pleuroatean 
the metoslaon) ; n, z., the middle xiphuid praceea; ca., tbe caiii 



mtemal, BxiAextemai xiphoid proeessea, Somotimea, a mediaa- 1 
process, ronlrwn or mateahriuvi (r., Pig. 81), is developed from [ 
the anterior angle of the sternum, and its antero-laterfd I 
angles are frequently produced into costal proceaaeB (e.ji^J 
'. I'ig. 81), which nuij bear the articular surfacca for moie <^ 





282 THE ANATOMy OF TEETEBEATED AMIMALS, 

fewer of the ribs. The two last-named stmctures are very 
dintinct in the Coraeomorpha;. oi- Pasaerine Birds. 

The eitent to which the keel of the lophoateon ia de- 
veloped in tho carinate birds varies Terymuch. In Stri^opt 
it ia rudimentary ; in birds of powerful flight, as weU aa in 
those which nae their wings for Bwimming, it ia eiceedinglj 

In the bird's skull (Fig. 82), tie brain-case is more arched 
and epa<;ious, and is larger, in proportion to the f ai3e, than 
in any Septula, with the esception of the Pteroauuria, 
There is a well-marked interorbital septum, bnt the eitent 
to which it is ossified varies greatly. Ab a general rule, 
the superior temporal bar is incomplete, and there is no 
distinct post-frontal bone. The inferior temporal bar, 
formed by the jngal and quadrato-jugal, on the other hand, 
ie always complete. There are no long parotic proceesee, 
nor any post-temporal fossse, the whole of each parietal 
bone being, a/i it were, absorbed in the roof of the ekulL 

The nasal apertures are almost always situated far back 
near the base of the beak. In the dry skull (above Mx. 
in Fig. 82), there is a lachrynao-nasal fossa, or interval 
unoccupied by bone, between the nassi, lachrymal, and 
maxillary bones, such as exists in some Teleoeauria, Ditio- 
aauria, and Pterosavria. 

The posterior nares lie between the palatines and the 
vomer; and the nasal passage is never separated from the 
cavity of the month by the union of palatine plates of the 
palatine or pterygoid bones. 

The Eustachian tubes generally traverHe the baaisplienoid, 
and have a common aperture upon the middle of the under 
surface of the skull. 

The bones of the brain-case, and most of those of the taoe, 
very early become ankylosed together into an indistiugnisb- 
able whole in most birds, bnt the sutures remain diBtingnj^- 
able longer in the Clienomorphce and SpheniseomorpJuB; and 
especially in the Ratitce. 

All the constituents of the occipital and parietal aeg- 
ments of the skull ore represented by distinct bones, but 



THE SKULL IN I 



tlo frontal segment varies a good deal in thia reepect. 
The Ijttsispbenoid has a, long roatrum, whieli represents 
partof the paraaphonoid of tlie -TeW^opRuia. Large frontal 




Flit. 82.— Lnlere 



Es of tbe miuidlble. 



bonea always exiit, but the pre-BphenoidaJ and orbito-'l 
apbenoidal regions are not so regularly ossified. 

Tbe ethmoid is ossified, and frequently appears upon tl 
surface of the skull, between tbe nasal and the frontaI_] 



2S4 TDK ANATOMY OP 

bones ; and the intemasal septum, m front of the ethmoid, 
may present very various degrees of ossification. Very 
frequently, the interBpaoe between the ethmoidal and the 
int^masal ossifcationa is simpiy membranous in tbe adult, 
and tiie beak ia held to the skull only hy the ascending 
proceaaes of the premaiillary bones, and by the nasal 
bones, which are thin and flexible. By this means a sort 
of elastic joint ia eatabliahed, conferring upon the beak a 
certain range of vertical motion. In the Parrota, and soma 
Other birds, this joint is converted into a true ajticulatjont' 




Fig. 63.— A longiludiDL. „ 
the Bkull of aa Ostrich, 



u cuulIs of 



and the range of motion of the upper beak becomea veij 
extenHive. 

The periotic capsule is completely ossified, and, aa in 
other Sicuropxida, the epiotio and the opisthotic are anky- 
loaed with the ocoipital segment before they unite with tlie 
pro-otic. In the primordial skull of the bird the olfactory 
organs arc surrounded by cartilaginous capsules, the lateral 
wallB of which send in Uirbinul processes of very various 
degrees of complexity. When the posterior wall of tliia 



THE SKULL Uf BIBDS. 285 

capsule is ossified, the bone thus formed represents the 
prefrontal, or lateral mass of the ethmoid, of the mammal. 
It is largely developed in the Apteryx, in the CastunridcB, 
and many other birds, but is absent in the StruthionidcB ; and, 
in other birds, is often represented by a mere bar of bone 
standing out from the ethmoidal ossification. 

The lachrymal is, usually, a distinct and large bone articu- 
lated with the nasal and frontal above, with the prefrontal 
internally, and with the maxilla, below ; byt sometimes it 
becomes undistinguishably fused with the prefrontal. Some- 
times, on the contrary, as in the Parrots, it acquires a large 
size, and sends a process backwards beneath the orbit, 
which may join with a post-orbital process of the frontal, 
and so circumscribe the orbital cavity. Opisthocomus ex- 
hibits the peculiarity of the complete ankylosis of the nasal 
with the lachiymal, which is quite free from the frontal 
and moves with the hinged beak. A supra-orbital bone, or 
chain of bones, may be developed in connection with the 
orbital margin of the frontal bone ; and, occasionally, infra- 
orbital bones, appear below the orbit, pai*allel with the jugal 
arch. A post-orbital process may be developed from the 
frontal, or from the alisphenoid ; and, in the latter case, 
may be sepai^ately ossified. 

The squamosal is closely applied to the skull, and is, 
usually, ankylosed with the other bones. It often sends a 
process downwards over the quadrate bone, and it may be 
united by bone with the post-orbital process of the frontal, 
as in the Fowl. 

The frame of the tympanic membrane not unfrequently 
contains distinct ossifications, which represent the tympanic 
bone of the Mammalia. 

The premaxillsB are modified in a manner which finds 
a partial parallel only among the Beptilia, They are 
tri-radiate bones of great size, which, usually, give off 
three processes; an ascending process to the frontal; a 
palatine process, along the middle of the palate, to the 
palatine bones; and an external, or maxillary process, 
which forms the greater part of the margin of the beak^ 



2S4 



THE ANATOMY OF VEBTEBEATED ANIMALS. 



bones ; and the intemaaal eeptmn, in front of the ethmoid 
may present very varioua degrees of oBBificat.ion, Tery 
freqnently, the interBpace hetween the ethmoidal and the 
intemasal oesificatiana ia simply membranous in the adult, 
and the beak is held to the skull only by the ascending 
proceasea of the premaxiliary hones, and by tLe nasal 
bones, which are thin and flexible. By this means a, sort 
of elastic joint is established, conferring upon the beak a 
certain range of Tarticat motion. In the Parrots, and some 
otlier birda, this joint ia conrerted into a true articuk,tion. 




Fig. 83. — A longitudinal (mil vorl a aec 
tbB ikull of an OBtnch P the p u ary foBM; aM.,p«:., antorioi 
and poeterinr vectioul semicareular canala of the ear. 

and the range of motion of the npper beak becomes very 
extenaive. 

The periotic capaule is completely osaified, and, as in 
other Saarapgida, the epiotic and the opisthotic are anky- 
losed with the occipital segment before they unite with the 
pro-otic. In the primordial skull of the bird the olfactoij 
oi^ana are ann'ounded by cartilaginous capsulcB, the lateral 
walls of which send in tvrbhuil proceaaea of very variooB 
degrees of complesity. Wlien the posterior wall of thia 



THE 8KU1J. IN BISDS. 

capsule is OBsifled, the bone thus formed represents the 
prefrontal, or lateral mass of the ethmoid, of the 
It ia largelj developed in the Aptery^r, in the Casual 
and many other birds, bnt is absent in the StrutTitonuIce ; 
other birds, ia often represented by a mere bar of 
standing out from the ethmoidal oaaification. 

The lachrymal ia.uBually. a distinct and large bone articn- 
]&t«(I with Uie nasal and frontal above, with tlie prefrontal 
internally, trnd with the maiilla, below; bft sometimeB it 
■becomes undistiaguishablyfuaed with the prefrontaL Some-j 
times, on the contraiy, aa in the Parrots, it acqnirea a 
and sends a process backwards beneath the i 
-which may join with a post-orbital proeesB of the front 
and ao circumscribe the orbital cavity. OpUiiwanmis ex- 
hibits the peculiarity of the complete ajikylosia of the nasal 
with the laehiymal, which ia quite free from the frontal 
and morea with the hinged beak. A supra-orbital bone, or 
chain of bonea, may be developed in connection with the 
orbital margin of the frontal bone ; and, occasionally, infra- 
orbital bones, appear below the orbit, pai-allel with the jugal 
arch. A post-orbitnl process may be developed fi-om 
frontal, or from the alisphenoid; and, in the latter c 
niay be separately ossified. 

The squamosal ia closely applied to the skull, and il 
naually, ankyloaed with the other bones. It often sends a 
process downwards over the quadrate bone, and it may be 
nnited by bone with the post-orbital process of the frontal, 
as in the Fowl. 

The frame of the tympanic membrane not unfrequent 
contains distinct oasiflcations, which represent the tympt 
bone of the Manvmalia, 

The premaxillte are modified ia a manner which finds 
a parti^ parallel only among the Repiilia. They nre 
tri-radiate bones of great size, which, naually, giye off 
three processes; an aacending proceas to the frontnl 
palatine process, abng the middle of the pala(«, 
palatine bones; and an external, or maxiUufy i,ro( 
which forms th«gieftt«r ^ut QJE' tin margi 



boi^^H 






286 THE A.N4T0MY OF VEETEBKATED ANIMALH. 

and unites with the maxilla. The two bones ai-e very early 
repi-esented hy one continuous oaaification. 

The Tomera vary more than almost any other bones of the 
Hknll. They underlie and embrace the inferior edge of the 
ethmo-preaphenoidal region of the basia cranii, and, is all 
birde in which they are distinctly developed, except the 
Ostrich, thej are connected behind with the palatine bones, 
In moat birds, they early nnite into a single bonej bnt 
they remain laag distinct in some CoraamwrphaB, and seem 
to be always separate in the WoodpeckerB. The coalesced 
vomers constitute a very large and broad bone in moat 
£alit<E, BJid in the Tinamomorpltai; anarrow elongated bone 
pointed in front in ScJiimgnothcB ; a broad bone deeply cleft 
behind, and abruptly truncated in front, in Coracomorpha. 
In most Desmognathee the vomer is small ; and, som.etimee, 
it appears to be obsolete. 

The ninvilln- of birds are usually slender, rod-like bones, 
articulating by squamous suture, in front, with the pre- 
maxUlffi, and, behind, with the equally slender jngale. Tn 
the great majority of birds the maxilltt sends iuwards a 
maxillo-palatine process (Pig. 82, Duep.), which, sometimes, 
is mere thin lamella of bone, sometimes, becomes swoUen 
and spongy. In the Xtiitit<E and the Besmognathoi (Fig. 84), 
the maxillo-palatine processes unite with the vomer, or with 
one another, and form, a complete bony roof across the 
palate. In the Schimgnaths [Fig. 82), and MgithogTudius, 
the maxillo-palatines remain quite distinct both from one 
another and from the vomer. 

The qnadrato-jugal is usually a slender rod of bone, die 
hinder eitremity of which presents, on its inner side, an 
articular head which fits into a fossa in the outer face of 
the distal end of the quadrate bone. 

The palatine hones are generally long and concave on 
their palatine faces. In front, they pass beneath {i.e., on 
the ventral side of) the maxiUo-palatines and unite with 
the premaiille, sometimes by a squamous suture, some- 
times by ankylosis, rarely, as in the Parrots, by a flexible 
joint. Posteriorly, they always nnite with the pta^r 



goida. In moet birda, tlie palatines converge, pOBteriorly, 1 
towarils the baai-splieiniidal rostrum, and unite with it hjm 
an articular surface, which allows of a, eliding motion of the 
palatines upon the rostram. Such on articulation does not 
exist ta Batiiee, or in the Tinamous, among the CarmaUe. 
In theae, (with the exception of Straihio), the palatines are, 
aa it were, home off from the rostrum by the divergent 
endfl of the great vomer, and the disposition of the parta 




Fig. 84.— The uncier mrftce of I)ic eniniiim of tho SecrcWry bird ( Gjt-M 
pogerantts), sa aii eianiple of Iho Deatnugnmhoua armngement. Jlap,^ 
maxillo-palatlne process | Bpl., Ijasi- pterygoid procesflCB. 

is more lacertillian than in other birds. The onter, ( 
posterior, end of the pterygoid bone presents a fossa for s 
articular head, which is developed npon the inner aide of 
the distal end of the quadrate. The inner, or anterior, tindfl 
of the pterygoids meet iu almost all birds, and may become . 
■rticulated with the basi-sphenoidal roatmnL In all e 
bryonic birds, in all the Batitm, and in many CarinaiiE. b 
U«B the TinamtmiorphiB, CharadriomorfiuB, Alet 



288 THE ANATOMY OP 

Periileromorphw, C'tWMMiwwy/uB, longer or aliorter pro- 
ceaaea eitend from tlie baai-Bplienoid, and presont tenmnal 
aiticular facets to correBponding facets upon the inner 
Bides of the pterygoids. Theee ai'S boH-pterygoid pro- 
cesses, similuj' to those which occur in LacerHlia and some 
ppftidia. 

The qnadrate bone is almost always moveahle npon the 
Bkull, artioulating with the pro-otic, aliaphet 
Bqnamoaal, by a single, or double, head. The distal head 
artieulatea with the mandible below, the quadrato-jugal oi 
the outer, and the pterygoid on the inner, side. Henct 
when the ethmo-nasat joint ia developed, any forward moTC- 
ment of the distal end of the qnadi^te, Buch as must take 
place when the mandible is depressed by the dignstrii; 
muscle, causes the maiillo-jugal bar to thrust the pre- 
maxiUa upwards and forwards^ the palatine and pterygoid 
bones, at the same time, eliding forward upon the rostrum 
of the basisphenoid. Thus it cornea about that the npper 
jaw of such a bird as a Parrot rises, when, in opening the 
mouth, the mandible ia depressed. Each ramus of the man- 
dible consists primitively of six pieces, as in other fiau- 
ropsida, but the dentary pieces of each side are, as in the 
Chehnia, very early nnited, if indeed they are not oastfied 
from one centre. Very often, a fontanelle remains Itetween 
the dentary and the other elemente, as in Crocodilia; and 
the dentary long remains readily separable from the rest ; 
or, as in the Groatsuckers, ia united with the others only by 
fibrous tissue, so that it is moveable. The angle of the 
mandible may be truncated or produced backwards into a 
long earred process, as in Fowls (Fig. 82), Ducks, and 

The hyoid is composed of basal elements, the anterior of 
which, usually composed of two portions, lies in the tongnej 
and of two short, anterior, and two long, posterior, conrntk 
which are never united with the periotic region of the 
skull, and commonly remain quite free. In some of the 
Woodpeckers, however, the long posterior comua are im- 
mensely elongated, and curve upwards and backwards over 



THE PECTORAL AKCH 1 



the skull (the frontal bones being grooved to receive them); 
ajid their free ejida are iiiaerted between the ascending axiM. J 
I masillary proceaaca of the right premniilla. 




(Sc), and coraoold (Co.) of a. Fowl ; , 
t right clavicle, Dt iighC biilf of the ft 



The pectoral arch presents a long, narrow, and n 
acapnia {8c. Fig. 84*1, without any snpracapnla; and. e 
coracoid (Co.), fitted by its proximal end into the giaovi 
in the anterolateral edge of the etemum. The inn 
of the coracoids oGcasionaJly overlap, aa in Laeertilia 
wise, the shoulder girdle ia nnlilte that of any of I 
BepUlia, except the Pterosauria. The coracoid is \ 
completely oasified, and preaciits no fontanelle. There ii 
no diatinet epicoracoid. The two bones take nearly equal 1 
sliaree in the foi-mation of the gloaoidal cavity, and usually ] 
rexuain nnaakyloeed and distinct iu this region. 

In the EatitiK the long asia of that part of the seapnla ] 
which lies near the glenoid cavity ia parallel or coinoidi 
with that of the coraccHd, and the two bones become eo 
jpletely ankylosed. But, in all the CarinaUe, the long a 
1 the acapnia forms an aente, or only slightly oTitnse I 
Bigle (Oeydrimius, Didus) with that of the coracoid. 
mall bone, the aeapvia aecemoria, is developed on the ai. 



290 THE AHATOMY OF VEKTBBBATED ANIMALB. 

Bide of the sbonlder-joiat m most Coraeomorplue and 
Cefeomorp/iiE. 

In the CariiuU<B, the glenoidal end of the acapnia ia 
dmdedinto two portionB; a glenoidal proceaa.'vihich expands 
to form the upper part of the glenoidal cavitj, and to Tinite 
with the coracoid — and an acromial process, which gives 
a.ttB4ihment to the outer end of the clavicle. The glenoidal 
end of the coTacoH is in like maniier divided into two por- 
tions; a gleamdal process, which unites with the scapoia, and 
& elatneular process, which articulateB with the outer surface 
of the clavicle, near its outer end. 

ThecIavicularprocesBof the coracoid prohahly representa 
the procoracoid of Laeeriilia. In the EatittB there ia no 
distinct clavicular process, hut the anterior part of the 
coracoid, near the glenoid cavity, maj be produced and 
separated hy a not«h, or fontanelle, from the rest, aa a 
lacertilian procoracoid. There is no ti-aee of clavicles in 
the Apteryx and in some Parrots. In the Emeu, and in 
sundry CarinatiE {some Parrots and Owls), the clavicles 
remain distinct from one another, or connected only by 
iibroua tissue; but, in the majority of birds, they are veiy 
early ankylosed together, and with the representative irf 
the interclayicle, in the midiile line, into a single bone, the 
furcaVmR,, the strength of which bears a pretly close re- 
lation to the exertion required of the wings in flight, or 
in natation. In the passerine hii-da the scapular end of 
the clavicle is usually expanded, and ossifies separatelji 
aa an epicieidiiun. A median process (hypo<:leidiii.mJ is 
frequently developed from the interclavicular part of the 
furculum, and this may be united with the carina of the 
sternum by strong fibrous tissue, or even by continuouB 
ossification. In Opiethacomus. the furculum is ankylosed 
with the manubrial part of the sternum, on the one handt 
and with the coracoids on the other. Ankyiosis of the fnr- 
ciilum with the coracoids has also been observed in Hidue. 

The fore limb of a bird, when in a state of rest, exhibits a 
gi'eat change of position if it be compared with that of an 
ordinary reptile ; audthischangeis of a character similar to, 



THE FOEE LIMB IN BIEDS. 

but in some reapccts greater than, that which the arm of 
man presents, when compared with the fore-limb of a quad- 
■rapedal mammal. The hiunems lies parallel with the 
of the body, its proper ventral surface looking outwards. 
The fore arm is in a position midway between pronation and 
Bnpination, and the manus is bent back upon the nlnar aide 
of the fore arm, in a position, not of flexion, but of abdue-. 

In ordinary birds, the proximal end of the humerus ii 
expanded, and its articular head transversely elongated 
ventral face is convex, and provided with a strong prea 
ridge, which gives attachment to the pectoral mnHcle. 
proper dorsal face is concave from side to side, especii 
towards the poatasial margin, where the pneumatic aperture 
occurs in those birds which have the humerus hollow. The 
distal end is expanded, and the articular surface for 
radius is a convex facet, directed obliquely inwards, on 
ventral face. In this reepeetthe bird's humerus exaggerate^ 
a feature of that of the Lizards. 

In the SatilcE these peculiarities are very feebly. 

at all, marked, the h\imenia being a slender, cylindrical, 

slightly curved, bone. In the CamMrid(E, IHtwmithidts, 

and Ajpterygidre, the fore-limb is eitraordinarily reduced, 

and may become rudimentary. In the Penguins and, to a 

less degree, in the great Auk, the bumems becom.eH flat- 

I tened from side to side ; the proximal end is singularly 

J modified, and, at the narrow distal end, the articnlar sur- 

I &ce for the I'adius lies completely in front of, and rather 

ibove, that for the ulna. 

The ulna, which ofben presents a aeries of tnbercb 

I indicating the attachment of the secondaiy quill feathi 

* ) usually a stronger, and a longer, bone than the radinBii 
j.There are only two carpal bones, one radial and 

In the ApterygidcB and in the Casuaridre, there ia bul 

)om.plete digit in the manus. It appears to answer to thi 

F-Beoondof thepentadactylelimb, and is provided with a claVi' 

a. ihs StruthionidiB and Rlieidte, and in all Carinatic, there i 



The 

the J 

, its ^1i 

ate«^^H 

ical, ^^^ 
iJ™ ■ 



f TEETEBEiTED ANIMALS. 

tJjreedigitBintlieinainiSjwliieh answer to thepollex and He 
aeeond and ttird digits of tlie pentadactyle fore limb; ajid 
the metacarpal bones of these digits are aniySosed together. 
„. „^ Ah a rule, the metacarpal of the poUes is 

much Bhorter than the other two ; that of 
the second di^t ia strong and straight, 
that of the third ia more slender and 
bowed, 80 as to leave an interspace be- 
tween itself and the second, which is 
often filled up by bony matter, The 
pollex baa two phalanges, and tbe second 
' of them is, in many birds, pointed, curved, 
and ensheathed in a homy claw. The 
second digit has three phalanges, and 
the terminal phalanx is aimilarlj pro- 
vided with a claw in aiindry birds. In 
the ostrich, both thepollei and the second 
ifFdigit are nnguiculate. The third digit 
never posBefisea more than one or two 
pbalangea, and is always devoid of a 

It is a singrdar circumstance that the 
relative proportions of the bumems and 
the ntanua should preaent the most 
marked contrast in two grottps of birds, 

f which are alilce remarkable for their 

powers of flight. These are the Swifte 
and Humming-birds, in which the hu- 
) merus is short and the manna long ; and 
the AlbatruBses, in which the hmnerus is 
■ long and the maniis relatively short. 
In the Penguins, the polles baa no 
So ligkt fireiimb ^'^6 phpJjmgea, and its metacarpal bone 
of a Fowl. The seems to be ankylosed with that of the 
K'of boih^'tlm ««"""! ^Sit. The tbiid metacarpal ia 
Hist Bail tlie le- slender and straight. The bones of the 
oond digitB were manus are singularly elongated and 




Fig.85.—Tlie radio 
W;ulnaM;ra 
dial sod ulnar cor 
p»l boDBH (r', u') 
with the three di 
frits (i.ii.,iii.), of f 



Thepelvi8ofabird(Fig. 86) IS m kabi for the g 

dongation, both, antei'iorly and p n ly of tlie i 

fconea {H.), which unite with tli wh 1 1 ngth f the edge 

if the Bocrom fsm.J and even extend forwdrda, over the pot^ 

Fig. 86. 




r riba of the dorsal regioa. Below, each iliac bone 
taawidearohovertbeupperportof theacetabuluni('ln)i 



294 THE ANATOMY 

the centre of which ia always closed by fibrooB tissue, BO th«^ 
in the dry skeleton, the bottom of the acetabulum ia pa^ 
forated by a wide foramen. An articular mirface on the 
ilinm , on which the great trochanter of the femur playa, is 
colled the antitrochanter. In all ordinary birds, the iBchinm 
(Pig. 86, is.), which broadens towards its hinder end, eitendH 
back, nearly parallel with the hinder part of the ilium, BJid 
is united with it by osaification, poaterioi'ly. The ilioaciatic 
intervalia thus converted into a foramen. The pubis (Pb.) 
enters, by ita doraal or acetabular end, into the formation of 
the acetabulum, and then passes backwards and downwards 
as a comparatively slender, curved, hone, nearly paraLel 
with the ischium. It ia united with its fellow only by 
fibrotia tisaue. Neither the iachia, nor the pubes, unite 
directly with the sacrum. Very few birds present any im- 
portant deviation from this structure of the pelvis. In 
Tiiia/nws, Casuarius, Drmiueue, Apleryx, JJiJiorMis, the iacbiuro 
is not united with the backward extension of the ilium bj 
bone. In Shea, the iachia imite with one another beneath 
the vertebral column, and the vertebne in this region are 
very slender and imperfectly ossified. In Stmtkio, alone, 
among birds, do the puhea unite in a median ventral sym- 
physis. Another, not less remarkable circumstance, in the 
ostrich, is, that the 3Ist to the 35th vertebnc inclusively 
(counting from the atlas) develope five lateral tuberosities. 
The three middle tuberosities are large, and abut against 
the pubis and the ischium, in these vertebne, as in the 
dorsal vertehne of Chelonia, the neural arch of each ver- 
tebra ahifta forward, ao that half ita baae a^ti<^ulates with 
the centrum of the neit vertebra in front ; and the tube- 
rosities in question are outgrowths, partly of the neural 
arch, paitly of the juxtapoaad vertebral centra, between 
which it ia wedged. Hence, in young ostriches, the face of 
each tuberosity eihibits a triradiate suture. 

The upper articular head of the femur ia rounded, and ita 
axis is almost at right angles with the body of the boue ; a 
structure which is not found in ordinary BeptUia, but exists 
in the Iffuaaodott, and other Ornithoecelida. The shaft is »- 



THE HIXD LniB IN BIBDS. 293 

lativelj short and thick, and the two tenmnal condyles axe 
large and elongated antero-posteriorly, A prominent ridge, 
which pliija between the proximal ends of the tibia and the 
fibula ia apparent upon the posterior and inferior surface 
of the onter condjie. A similar ridge is faintly developed 
ome Laeertilia, and ia well marked in the Dinoaaurian 
reptiles. A patella is nanally present, but it ia sometimes 
absent, and may be double. yI". S'. 

The fibula of birds is always im- cn ck 

perfect, ending in a mere style 
Ijelow. Generally it )s decidedly 
shorter than the tibia, but it hua 
same length as that bune m 
} Penguins. The tibia or ' 
rather tibio-largut, is a highly cha 
racteristio bone. Its proximal end 
a expanded and produced ante 
iorly, into a great cnemial process 
(which may be variouelj subdi 
Tided) as in Dinotauria. The distal 
end is terminated by a well-marked 
puUey-liie articular surface whieh 
"iclined somewhat forwards as 
well as downwards. Not unfre- 
quently there is an obliqne bar of 
on the anterior face, jiist 
above the pialley, beneath whii;li 
the long extensor tendons pass. 

The extremity of the cnemial 
process in Stnithw and Rkea is 
ossified as an qilphjsis ; and, iu 
young birds, the whole of the dis- 
tal artienlar end of the bone ia 
separated from the rest by a su- 
ture, and also appears to be an epi- 
physis. But it ia, in fact, as Professor Gegoiibaur has 
proved, the proximal division of the tarsus (apparently 
representing only the astragalus of the other Yerlebrtii' 




fig. 87.— Tha riglif libiit 
and fibula of a Fowl. A, 
front view; B, extotnil 
lateml view. T,, tibia: 
F„ fibula; Ca., knemM 
priMiOBs; Ai., aaliugslus. 



Fig, 88. 




aJB THE ANATOMY or TEETEBKATED ANIMALS. 

whioli esista in the embryo as a separate cartilage, and, as 
it oBsifiea. ankyloses with the tibia. The so-called tibia rf 
11 bird is therefore, properly speakitig, a ft&i'o-farsMs (see 
p. 263. Fig. 77, A, and Fig. 88). 

In all birds, evea in Archaaipteryx, the fifth digit of the 
pea remainB undeveloped ; and the second, third, and fonrth 
metataraiila are ankylosed together. 
and, by their proximal ends, with a 
bone, which ia a diatinct cartilage in 
the fcetua, and represents the distal 
division of the taraus. Thus a iarm- 
vietatargim is formed. The distal enda 
of the metatarsals remain separate, and 
ofl'er convex articnlar aurfacea to the 
proximal phalanges of the di^ts. 

In the Penguins, large apertures lie 

between the sevra^ metatarsals of the 

adalt iarao-iKetatarsus i and, m other 

' 'end'nr7hB"lefl"dbra l^irdS' more or leaa coneiderable pas- 

{ 7*.) with the at- Bilges persist between the middle and 

i™^'i.t^B'jr.w ^"^ l»*e™l metataraals proiimallj, and 

Fowl, Viewed from the middle and the outer, distallj. In 

in tVont, ond from moat birds, the middle metatarsal doet 

not remain parallel with the others, Init 

its proximal end inclines a little baekwards. and its dutaJ 

end a little forwaj'da. Hence the two apertures on each side 

of ita proximal end may lie at the bottom of a foaaa, or nm 

into one, in front, while they remain distinct behind. 

Again, in most birds, the posterior face of the proximal 
end of the middle metatarsal, and the adjacent surface of 
the tarsal bone, grow out into a process, which is commonly, 
but improperly, termed " calca.newl." The inferior enrfae* 
of this 'i^po-fiirKus is sometimes simply flattened, sometjmes 
traversed by grooves or canals, for the flexor tendons of the 

Wben a halltii exists, its metatarsal bone ia nsnallf 
incomplete above, and is united by ligament to the inner, 
oi- the posterior, surface of the tarso- metatarsus. In ^hft 



r rs BiEDS. 




igate-bird (Fhaelhon) and m StealomU, tbe h: 

metatarsal is remarkalilj long. The genns Phaethon 

twras 1 know, in liaving the g;^, gg. 

allneal nietatareal aukylosed with 
e others. 

In many of the AkctoromoTphtc, a 

{calear), consigting of a bony 

e eusheathed in horn, is developed 

I the inner side of the metatarBua, 

ind becomes ankylosed with the me- 

^taraal of the second digit. In a fen 

aimilar apurB (Pntowa/ea), or 

LB excrescences {Pe^^}phap^), are 

' developed in relation with the meta- 

Tho normal nnmber of the pedal 

phalangea in birds is (as in ordinary 

Lacertilia) 2, 3, 4. 5, reckoning from 

the hallux to the fourth digit. Among 

tte few birds which constitnte eicep. 

tions to the rule are the Svrifts, in 

I -which the third and fourth toe have 

I xmly three phalajiges each ('2, 3, it, 3). 

I ajid the Ooatauckera and the Sajid- 

E grouse, in which the fourth t«e only 

I IxsM the numl>cr thus reduced (2, 3, 4,3). 

Many birda have only three toes, by sTipproaaion of tlij 

In the Ofltricli, not only the hallux, but the phi 
mges of the second digit, are suppressed; and the dii 
md of the second metataraal is reduced to a, mere rtidimeni 
PCence the ostrich haa only two toes (which answer to th( 
iiird and fourth of the pentadactjle foot), with four pha-' 
the inner and five in the outer, though the 
e is far the longer and the stronger. 
In most four-toed birds the hallui is turned more oi 
mpletely backwarda, and the other three digits forwarda.i 
a many .lieionwiyhiF (especially the Owla), the outer toe( 
u betnnted outwards, or evea backwards, at will. And 



1 









consisting of 






' TBETEBaATBD 

the Parrota, Toucans, Cuckoos, Woodpeckers, and other to- 
called *■ Bcansorial " birds, the outer toe ia permsiicntlj re- 
versed. Under these circmnatancea the distal end of the 
outer metatai-aal may be divided into two distinct articuki 
Hurfafiee. In the Trogons, there are two toes in front and ta 
behind, a,9 in the Parrots, but it is the second toe which ia 
turned backwardfi. Lastly, in the Swifts, the Dyapm-omorpia 
und the SplutniscomorphcE, the halloz is directed more or 
forwards, so that all four toes are turned to the front. 

As a, general rule, the osseous tissue of birds is rem: 
ably dense and hard. Before hatching, the bones are eoli^ 
and filled with vascular medulla; but, after birth, : 
fewer of the bones are always eicavated by prolongations 
of cavities containing air, which lie in their neighbonrhood 
Such air cavities are always found in the skull, i 
tion with the nasal and auditory passages, and they may 
extend through all parts of the skull, with the exception 
the jugal arch. In many birds, such as the Apteryx, Pen- 
guins, Divers, GuUb, and the smaller song-birds, no otitet 
bones than those of the aknU are pneumatic ; 
birds, theairsucs of the lungs send off prolongations into the 
bones of the rest of theskeleton, and thus the whole skeleton 
in some cases (as in the Hombills) becomes pneunialu. 
It is proper to remark, that the amount of pneumaticity of 
the bones by no means foUowe the development of tlw 
power of flight. In the Ostrich, for e:cample, the bones an 
far more extensively pneumatic than in the GulL 

In some cases, prolongations of the air sacs extend Iwy 
neath the integument. 




r 



B MUSClBa AND THE 




CHAPTEE VII. 



, important deviations from the ordinary ar- 



gement of the imiHcnIar systein occor, its niigbt be 
Bpeeted, in the Ophidia, in the CheUmia, and in Avea, In 
firBt-mentioned group, the numeruns masclca of the 
imba are, of course, absent, and the mobility of the J 
rertehne, ribs and jawa, ia accompanied by a corre* I 
Iponding differentiation of the musclea of those part8> 4 
rhe epiakeletal muBcles form o, contiauona series (divia- 
[e into ipinaU$, seminpinalit, longigaimug dorgi. leealaret 
iianim, and other muscles) from the end of the tail to 
e head ; and, in the region of the back, constitute a thick 
isB which extends ontwarda to the enda of the caudal ribs J 
le so- called tronsTerse procesaea), and over the dorsal tbirdsl 
the other ribs. Beyond these points it is continued, as afl 
layer of muscular fibres, over the ventral half of the ' 
ul and trunk, passing from rib to rib in the latter region, 
rhere the more dorsal fibres are directed obliquely, only a 
mgitndinal band running along the extremities of the ribs 
nd representing areefusaAdoiimtu. This musole is continued 
:>rwardB to the hyoidean appaj^tua, and thence to theman- 
ible. Superficial mascnlar bundles paas from the ribs to 
he BcolcB. The hyposkeletal mnscles are better developed 
han in most other Vertebrata, and also extend from the head 
o the end of the tail. A median dorsal set are connected with 
he subvcrtebral prooeBsea in the tnmk, and with the bases 
f the representatives of the chevron bones in the tail, i 
lase to the caudal and dorsal ribs. One set of these, in 
anink, act as retractors of the ribs. The muacles wbioi 



300 THE ANATOMY OF VEKTEBBATED ASIMAIi. wM 

correspond witli the trajisuermig ahdominw, commence in the 
tail bj tranBversely directed bimdleB of flbrea, which anM 
from the roots of the caadal ribs (tranSYeree processeel aal 
meet in a median aponeurDsie. In the trunk, eimilar btmdlei 
ariee from the nnder suriaoee of the ribs, and form t«o 
layers of oblique fibres, which also meet in the middle line. 
In the Chelonia, the epiekelelal musclea are alwaye weaklj 
developed, and may be altogether abortive in the donal 
region, while those of the abdominal walla are small. Tht 
recti are very weak, but muaclee answering to the pyrowt 
dales extend from the pubea to the inner surface of ihi 
plaatron. A muscnlflr expansion ajialogona to a diaphra^ 
may he attached to the bodies and ribs of the third mi 
fourth dorsal vertehiie, whence it expands over the surfnoe 
of the lungs. No muscles pass from the bead to tig 
shoulder girdle. The pectoral arch is protracted, ani 
the neck retracted, by a muscle attached to the cervinl 
vertehrEB and to the procoracoid. There is also a aingk 
retractor of the pectoral arch, apparently repreaenting I 
Berraiua nwyjHM, and passing from the first costal plateto 
the scapnla. The pectoralie mojar arises from the iiuur 
surface of the plastron , The representative of the M» 
siimis dorsi arises from the inner side of the first ooatd 

The cutaneous muscles of birds are well developed, md 
foi-m broad expansions in various ports of the body. Spedil 
bundles of muscular fibres pass to the great quiUfeathenct 
the tail and wings, and others to \ii& patagium, a fold of i>- 
t^fument which extends between the trunk and the braduo* 
behind, and between the brachium and ante-brachinm il 
front. In correspondence with the shght mobility of tiK 
dorsal vertebra, the episkeletal and hyposkeletal musdix d 
the spine attain a cunsiderable development only in tk 
neck and in the tail. Owing to the great size of Um 
sternum, the abdominal muscles are nsually small, and tin 
internal oblique may be absent. A diaphi-agm, conaistiDg 
of bundles of muscular fibres, which pass from the ribs to 



NBUBOLOGY OF THE 8ATJBOPSIDA. 301 

the aponeurosis covering the ventral face of the lungs, is 
developed in all birds, but attains the greatest degree of 
completeness in the Batitce, and especially in Apteryx. 

The muscles of the limbs are remarkably modified by the 
excessive development of some of those found in other 
Vertebrata, and the suppression of others. 

Thus in all birds possessing the power of flight, the 
pectorcdis majors as the chief agent of the downward stroke 
of the wing, is very large and thick, taking its origin from 
the whole length, and a great part of the depth, of the keel 
of the sternum. 

The elevation of the wing is chiefly effected by the 
jpectoralis tertiusy which arises beneath the foregoing muscle, 
and passes over the inner side of the scapulocoracoid 
articulation, as over a pulley, to reach the humerus. The 
muscles of the forearm and digits are reduced, in accordance 
with the peculiar modification of the skeleton of these parts. 
In the hind limb of most birds there is a singular extensor 
muscle, which arises from the pubis, ends in a tendon which 
passes to the outer side of the knee-joint, and terminates 
in the leg by uniting with the flexor digitorv/m perforatibs. 
The result of this arrangement is, that the toes are flexed 
whenever the leg is bent upon the thigh, and, consequently, 
the roosting bird is held fast upon his perch by the weight 
of his own body. 

In all the Sauropsida the cerebro-spinal axis is angulated 
at the junction of the spinal cord with the medulla oblongata, 
the latter being bent down towards the ventral side of the 
body. The region in which the nerves of the anterior and pos- 
terior extremities originate may be enlarged in reptiles, as 
in birds ; but, in the former, the posterior columns of the 
cord remain parallel in the lumbar enlargement, while, in 
the latter, they diverge and give rise to the sinus rhom- 
hoidaliSf which is a sort of repetition of the fourth ventricle, 
the dilated central canal of the spinal cord being covered 
merely by a thin membrane consisting chiefly of the 
ependyma and arachnoid. 



F VEKTEBKATED ANIMALS. 
Fig. BO. 




Fi|;. 9(1.— A, C, the bruin of a Lizard (i>sRwnio(i»rHa bengaltia. 

B, D, of a bird {Mehlagra galioptma, tlie Turkej'), drawn u ifcliti 
were of equal lengths. A, B, viewed Irnm nbove ; C, D, fniinth«ltjl 
aide, off.. Olfactory lobes; Pn., Pineal gland; Ump., oerebni 
hemisplieres : Mb., optic IoIms of the mid-brain; Cb., ccrebellnn ; 
jtf. O., medulla oblongata; ii.,ic., ei'., second, fourth, and sixth p 
of cerebral nerves ; Py., pituiiac j hody. 

The brain (Pig. 90) Hie the carity of the akull in t 
higher Sawropsida, and presenta o, well -developed cerebeUnni; 
a mesencephalon divided above into two optic lobes ; and 
relatively large proeencephalio hemiapherea, which attain 1 
considerable size in CrocodiUa and Avee, but never coacc^ 
the optic lobeB. In Crocodilia the cerebellum presents i 
distinct vermie, with transverse fiaBurea. In birds the 
latter are more distinct, and the lateral appendages of the 
cerebellum, or Jloceuli, become well defined, and are lodgedi 
aa in many of the lower Manmialia, in cavities of tlie mk 
walla of the akull, arched over by the autei-ior Tertical 
aemicircvUar canal. 

There ia no potis Varolii, in the sense of tranaverBe Shie$ 
connecting the two halves of the cerebellum, visible upon 
the ventral surface of the mesencephalon. The optic lobei 
contain ventricles. In Btplilia, the optic lobes usually lis 
eloae together u^Kin the doi-sa,l aide of the mesencephalon. 



KBPKOIOGT OP 1 

rat in Ave$ (Fig. 90 B, D) they iire thrown down to the 
iidea of the htiae of the brain, and are conuected over the 
IjwtedurfiM Sixfoil by u, broad coinmisBural band. 
Each proBencephalic lobe contains a lateral ventricle 
Fig, 91. 



fj£ 




upper figure repreaenU tlie lizard's brain ; the lower (tsken, like 



r wall of the third venlrlele ; /. M.. tbraoien of 
1IIUUI1I-, u., luitorlor Eommiasure ; TVi. £., tholnnioncephalDii ; 
«., soft commiMnre; p., posterior commigsure ; ip,, indientca tiip 
eiBCt point of exit of the fourth pair from timt part of tUe brain 
whicb uuwen to the Talvi of VieosaeDS. 



d 



30t THE ANATOMY OF TERTEBEATED 

(continuouB tlironi;li the foi-amen of Munro witli the thiri 
ventricle), which ia little more than a fisBure between lie 
very thia inner wall of the lobe and its thick outer part, 
which contains the corpus atrisituni. The corpora striati 
are united hy an anterior cominissnre, which ia not of Isige 
size. The thinning of the inner wall of the lobes, from ti« 
margin of the foramen of Munro backwards, Vfliich gives 
rise to the IJasure of Bichat in the Maminalia, extends for. 
very short distance in the Sauropxida, even in birds. 

The olfactory lobes are usually elongated, and contwn 
ventricles continuous with those of the prosencephalit 
hemispheres. 

In all iSaiM-ops-iin the motor nei-vea of the tongue paa 
through a foramen in the ei-occipital bone. Hence, twdre 
pairs of cranial nerves are present, except in the Ophidia. 
which posaesa no spinal accessory nerve. 

The lateral ontaneouB branches so generally sent to the 
trunk by the pnenmogastric in the lehthyopeidu. are absent. 
but the pneumogastric gives a recurrent branch to tJte 
larynx. The third, fourth, and sixth neir-es arise quite 
independently of the fifth. 

The sympathetic is well developed, except in the Ophi^, 
where it is not distinct tram the spinal nervea, in tiw 
greater part of the tnmk. 

The Ophidia. many Sauria, and Aves, poaaeae 
glands, which, in birds, attain a large size, and lie 
usually upon the frontal hone, or in the orbits, than i 
uasal cavity. 

The eye, rudimentary in some Oplddia and LaeertUia, is 
usually large ; and, sometimes, as in many birds and in the 
extinct Ichlhyosaiiria, attains very great absolute and rela- 
tive dimensions. 

In the Ophidia and some Laeerlllia (the AinphithiBMidtii, 
some Saincoidea, all Atealobata), the integument is exm- 
tinned over the eye, and becomes transparent. Tbiem 
reptiles are commonly said to possess no eyelids; but it 
must be remarked that this is not true of them in the 



305 J 



ETHE 1 
.Be in which it is true of must oBseous fiaheai : 
nsparent covering of the eye really repreaenta th&J 
I eyelids of the higher VertebnUa, and ia Beparated m 
from the oyebaU by a chamber lined by coiyunctiv^ 1 
irhich commmiicatea with the nose bj a, iBichrymal canal. 1 
In the other SoMTopsida two lida are developed, and each i 
generally poeaesaes a special palpehml muscle, which 
acta as an elevator of the upper, and a depressor of the 
lower, lid. In some Seincoidea the middle of the lower lid 
is tranaparent. In manj liacei'tilia it contains a cartilage 
OF an oaaification. 

Moat lizards, all Chelonia, Crocodilia, and Avea, poeeess.l 
a nictitating membrane moved by epeoial muacles, which 1 
present three different arrangements. 

In the lizards a short thick muscle {bursaUsJ ia attached I 
to the inner and posterior wall of the orbit, and a 
fibrous aheath. A tendon, one end of which is attached to 1 
the presphenoidaJ region of the inner wall of the orbit, - 
passes backwards through the sheath, and then forwarda to ■! 
be attached to the niotitating membrane. When the muscle I 
contracts, it necessarily pulls the latter o ' 

Harderian gland is always developed, and alachrymal gland I 
very generally, though not always. 

In the Chdonia. muscular flbres (forming the so-called \ 
pyramidalia muscle) arise from the inner side of the eye- f 
ball, and, arching over it and the optic nerve, are inserted 1 
partly into the outer edge of the nictitating membrane, | 
partly into the lower eyelid. The Crotodilia have a -py- 
ramidaiwmuscle taking the same origin and course,- but it I 
sends no fibrea to the tower eyelid, ita tendon being inserted f 
altogether into the nictitating membrane. 

The third arrangement, which in a manner combines 
together the fii-at and the second, is that aeen in birds, i 
pj/raiHMiiiitsmtiBcle, arising from tlieinner and under Hurfac 
of the eyeball, soon ends in a tendon which sweeps i-ound 
the upper and outer eurfacea of the sclerotic to the nicti- 
tating membrane, as in the crooodilea. But there is also a J 
bwratdix muscle, which however i 



' VEETEBEATBD ANIMAI.S, 

from, tlie wall of the orbit, but from the upper auriuM 
of the sclerotic itself, whence it paHHea backwat'da i 
ends ia a fibrous eheath which incluBea the tendon of 
the pyramidalU. The contraction of thia muscle neces- 
sarily tends to draw the tendon of the pyramidalw awaj 
from the optic nerre. A tubercle is sometiinea developed 
from the sclerotic above the entrance of the optic nerve, 
and prevents the tendon of the pyramidalia from ahifting 
forwurda and inwai-ds. 

The eyeball ia alwa3^ moved by four recti and two 
obliqui. The auperior oblique does not pass over a pulley. 
The Ohelonia and moat LacertUia have h, more or lees ooni- 
pletely developed retractor, or choonoid, muscle. 

A ring formed of bony plates is developed in the fore 
part of the sclerotic in LaEcrfilia, Cliehmia, Ichthyosavria, 
Dicynodontia, Pteroeavna and Aves, but not in C^liidia, 
Pleewtawria, or CrocoAUia 

The iria and the tensor choroidei contain striated n 
cular fibres. 

A peeten ia very generally developed. It attaina a large 
size, and becomea much plaited, m moat Aves. 

Only Crocodilia and Aves pos 

The Ophidia and the Ampkisbcenoidea have no tympanic 
cavity. In some Clielonia, in Sphenodoa, and in the Chame- 
leons, the tympanic membrane ia covered by the int«gn- 
ment, but a tympanic cavity exists. In LacertUia, tlie 
tympanic cavities communicate by wide openings with the 
pharynx ; but in Chelotda, Crocodilia, and Aves, the ootU' 
municating puasagee, reduced in size, become Eustachian 
tubes. In the CheUmia, these curve backwards, downwaida, 
and inwards, round the quadrate bones, and open eeparatelj 
on the roof of the mouth. In the CroeadUia there are, u 
has been described above (p. 255), three Eustachian tubes 
^-one median and two lateral. In Aves, there is but one 
Eustachian aperture, answering to the median of the CrooO' 
dilia ; and, as in the latter group, each Eustachian tube 



I THE AUMENTAET CANAL IN SACKOPSIDA. 307 

nsuftllj ti-aversee the OBseous base of the akuU, to join -with 
its fellow in the common aperture. 

The stapes is a columelliform bone, the outer end of which 
is attached to the tympanic membrane, where the latter is 
dereluped; but lies among the muaclea when there is no 
tympanic cavity, 

AH Sauropeida posaees a fenestra rotimda, as well as a 
fenestra ovalw, and all have a cochlea, which is never coiled 
spirally, and is more mdimentary in the Chelania than in 
other groups. Three eemieircular canals, an anterior and 
posterior vertical, and an estemal horizontal, are connected , 
with the membranoua Teatibnle. In Aues, the anterior I 
vertical canal is very large in proportion to the others, and i 
the adjacent crura of the two vertical canals overlap before j 
they unite with one another. 

Labial and buccalglands are developed insomeSawt-opsida, 
and one of them, on each side, attains a lai^ development is I 
the poison glands of the venomous snakos. Well -developed .1 
sablingnal, suhmaiiDary, and parotid glands appear i 
Sirda,andthe sublingual glands attain animmense size in tl 
Woodpecker. Tho tongue varies greatly, being Bometimes 
obsolete, as in the Crocodile and some birds {e.g. the Peli- 
cans), sometimes horuy and even spinose, sometimes fleshy. 
In the snakes, and some lizards, the tongue is forked, and 
capable of retraction into a basal sheath. In the Cha- 
meleons, it is clubbed at its exti'emity, and can be retracted 
or protruded by the invagination or inversion of its hollow 

I The alimentary canal of the Sawopeida is generallj 1 

divided into an {esophagus, a simple stomach, a smaJl I 

intestine and large intestine, which last always terminates ] 

in a cloaca. It is invested by a peritoneal coat, whioh 1 
generally follows all the cui'vatures of the intestine. But 

in the C^hidia, the folds of the small intestine are united 1 

Jij fibrous tissue, and enclosed by a common sheath of | 

ritoneum. 
L The stontach is usuaUy a. simple dilatation of the a 



308 THE ANATOMY OF VEETEBEATED ANIMAXB. ^1 

tury canal, the cardiac and pyloric apertorea o( irhiuli aM 
veiEote from one another ; but, in the Crocodiles, and in 
most Birds, the pyloi-ic HJid CH<rdiac aperturea are appron- 
mated. In many Croeodilia and Avee, there is a pjloric 
dilatation before the commencement of the dnodenmn. 

In the Croeodilia, and in Avea, the weJIb of tlie Btonutdi 
lU'e veiy muacular, and the mnacnlar fibres of eacli side 
radiate frum a central tendon or aponeurosis. The tliick* 
ening of the muscular tunic of the atomach attains itfi 
maximuni in the graminivorous birds ; and it is eccom- 
panied by the deyeiopment of the opithelinm into a dense and 
hard coat, adapted for crushing the food of these ajumala. 
Birda commonly aid the triturating powei- of tliis gaatrifl 
mill by swallowing stonea ; but this habit is not confined to 
them, crocodiles having been observed to do the same tiling. 

Birda ai'e further remarkable for the development of ft 
broad zone of glands in the lower part of the ceaoplu^iu, 
which is naually dilated, and forms a proverttricuiiu. 
connected by a narrow neck with the above-menticoied 
muBcolar stomach or gizzard (gigeriwm). 

Some Opiiidia have a ccecum at the junction of the smaS 
intestine with the largo ; and two such cteca, wbich some- 
times attain a large size, are Tei-y generally developed in 
Avee. In this clase also, the small inteatine, not nnfre- 
quently, presents a ctecal appendage, the remRJns of tite 
vitelline duct. The duodenum of Birda constantly makes 
a loop, witiiin which the pancreas liea, aa in Mammalia. 

The liver in the SaurqpHda almost always possesaeB ft 
gull bladder, which ia usually attached to the under suxfaM 
of the right lobe, but in the Ophidia ia removed to Bome 
distance from. it. 

A peculiai- glandular sac, the Bursa Fabricit, opeiiB into 
the anterior and doraal region of the cloaca in birds. 

Three forma of heart are found in the Sauropsida. The 
first ia that obaerved in the Chelonia, Laceriilia, and Ophidia; 
tbeaecond, that in the Croccdiliat and the third, that in ^wk 

1. In the C/wioitia, Laceriilia, and Ophidia, there are 



THE HEABT IN SAUK0P8I0A. 

fcuricleH. Generally, a distinct ffi'niw tiBTujsMs, with contractile I 
.Is, Eind communicating by a, vaJviilar apei'tnre with, the 

fcuricle, receives the hlood from the veiue oavce, and pours 
b into the right aniicle. The pulniouai7 Teina usually 
n hy a common truni into the left auricle. 
The interam'icular septum is rarely (iu Bome Ckelonia) 
perforated. Its ventricular edge Bpreads out on each side ■ 
into a broad memhi-anons valve, the edge of which, during ■ I 
the systole, fiapa against a ridge, or fold, developed, on one, 
or both, sides, from the margin of the anriculo-yentricnlar 
aperture, and constituting a rudiment of a second valve. 
The ventricle contains only one cavity, but that cavity is 
impei-fectly divided into two or three chambers, by septar 
developed from ita muscular walls. 

In the Turtle (Fig. 92), a paiily musculai', and partly i 
cartilaginous, septom extends from the front wall of the 1 
ventricular cavity towards its right-hand end. It 
perfectly divides the common ventricular cavity into uJ 
right small, and a left large, moiety. The latter of theeAV 
receives the blood from the auricles. la consequence dt'« 
the elongated form of the ventricular cavity, and the pro's 
jection into it of the large anrioulo- ventricular valvaa,* 
eapecially of that of the right side, this left and larg^fl 
moiety of the common ventricle is virtually divided intoiM 
two, a left and a right, at the time of the auricular systole; 1 
The left portion hecomes filled with arterial blood from the I 
left auricle, and is distinguished as the cavum arteriommt j , 
the right receives the venous blood from the right aur" 
and is the eavam TenosTiin. 

No arterial tmnk arises from the camiari, arteriosvm,, bnt tw» "J 
arterial trunks arise from the right-hand end of the ca 
venoswin ; these are the two aortic arches. One of these I 
passes to the left and the other to the right side, and they I 
cross one ajiother as they do so, because the origin of the • 
left arch lies more to the right, than doea the origin of the 
left arch. The oatia of both arches are guarded by s. 
lunar valves; and that of the left arch is placed below and 
to the right of that <tftbe fight wch. As no arterial trtmk 



THE HEAET IN SATTttOPSIDA. 3Hl 

The rigiit, comparatively small, moiety uf the ventricle 
is Bepai'ated from the cavam, VBitoswm by the already 
juentioned septum, which ia attached between the origin 
of the left aortic ai'ch, and that of the pulmonary ari^ery, 
its free edge looking towarda the dorsal face of the heart. 
Thus thf pulmonary artery arises from what is, vb-tiually, 
separate Hubdiviaioa of the ventricle, or 
momUe. 

When the systole of the ventricle takes place, the pi 
tioal result of these arrangements is, that the pulmonaiyi 
artery, and the aortic arches, at first, receive wholly venous 
blood from the eavum, vetiommn and cavwm puhnonole. Bst 
as the arterial blood of the cavwn aHerhawn, ie driven into 

cavum venosimHf, the venous blood of the latter tends 
be excluded from the mouths of the aortic arches, 
to be driven into the canum, jaiilmoiude, while the 
arches receive urterialiBed blood. The left arch ri 
a larger proportion of venous blood than the right, . 
ventricle contraota, the free edge of the muscular s 
approaches the dorsal wall of the ventricle, and gradually 
ciosea the access to the cavifin pulmoiuxlo, which thus final^, 
espela the venous blood which it received from the 
venosam, but admits none of the ari«rialised blood; 
Bequently none of this reaches the longs. 

2. In the CraEodiiia, the cavmn. venoman and the 
arteriogwm are converted into perfectly distinct right and 
left ventricles. The right ventricle gives off the pulmonary 
artery, and, in addition, an aortic arch which ci'oeses over 
to the left aide. From the left ventricle only a single truni 
arises, and this, crossing to the right side, becomes the 
right aortic arch, of which the dorsal aorta ia the direct 
continuation. The walls of the two aoHic arches 
contact whei'c they cross one another ; and, at this poiaf 
.a small aperture, situated above the Bemilunar valves, pli 
the cavities of the two arches in communication. 

Thus, in the Crocodilia, the venous and the arti 
currents communicate onlyoutaide the heart, not within 
as in the foregoing groups. 



aUy.a ■ 

:pra<i^^H 
lonai^p^^^H 
enons I 

Bst 
linto 
idsta^^J 

Uthe I 




312 THE ANATOMY OP VEKTBBBATBD 

The septnm of the cawini- pahnonate reinaine as a email 
muaonlar banti, and the fold of the outer lip of each 
anricnlo-ventricular apertiu'e, haa hecome a distmct mem- 
hi'anoua valye. 

3. In Aveg, the venoiia and arterial blood cunvaits, com- 
municate only iu tlie pulmonarj' and ejstemio capillariea. 
The auricular and ventricular aepta are complete, a« in 
the Grocodilia ; hnt the right ventricle givee off only the 
pulmonary ai-tery, the left aortic ai-ch having disappeared. 
The septum of the cavum pulmonale becomes a. great 
muBoular fold, and takes on the function of an auricolo- 
Tentricular valve. At the origin of the pulnionaiy artery, 
and at that of the aortic ai-ch, three semilunar Talvee aw 
developed. 

In Reptiles there are usually only two aortic archea, one 
on each side, answering to the fourth pair of archea of the 
embryo. The right gives off the carotid and Bubclaviaii 
aileries, and pasaea directly into the trunk of the dorsal 
aorta. The left commonly gives off viaoeral arteries, and. 
becomes a good deal diminished in faze befoi-e joining' the 

In m.any Lacevtilia, four aortic arches, (anewering to tJifi 
third and fourth paira of the embryo,) persist, two anteriiw 
arches, from which the carotida are given off. springing, by 
a common trunk, from the right ordinary aortic arch. 

In the Reptilia, moat of the blood of the hind limba and 
tail pasaea through one or other of two " portal eyetema" 
before reaching the heart, the one portal system lying ia 
the kidney, the other in the liver. The portion which goes 
to the Lver ia carried to it mainly by the anterior abdominal 
veins, which are represented by two trunks in most MeptiUa, 
by one in the Opiiidia. 

In Ams there ia no renal portal aystem, and the anterior 
abdominal vein opens into the inferior vena cava clos6 



to the heart. Nevertheleas a median trunk, which i. 






off from the caudal vein, carries a considerable proportion 
of its blood directly into the hepatic portal system. 



THE LABYNX IN SAXTBOPSIDA. 313 

All the Sauropsida possess a larjmx, a trachea, and one 
or two lungs. The bronchi do not divide dichotomously, as 
they do in Marrumalia, 

In Chelonia and Crocodilia the larynx consists of a 
circular cartilage, apparently coiTCsponding with both the 
thyroid and the cricoid of the higher Vertebrata ; and of 
the arytenoid cartilages, articulated with its anterior and 
dorsal edge. 

The Lacertilia have, for the most part, a similar larynx, 
buu the circular cartilage is often interrupted by round, 
or elongated, membranous f ontanelles. In the Chamseleons, 
the mucous membi*ane of the larynx between the circular 
cartilage and the first ring of the trachea protrudes in the 
form of an air sac. 

In the Anvphishcenoidea, and in the Ophidian the skeleton of 
the larynx consists of two lateral longitudinal bands of carti- 
lage, united by from four to sixteen transverse bands. In 
other words, the structure which answers to the circular 
cartilage is greatly elongated, and has many transversely 
elongated fontanelles. There is a single arytenoid car- 
tilage, which is sometimes represented by a process of the 
anterior dorsal margin of the circular cartilage. An 
epiglottis is rarely present. 

In Birds there are distinct thjrroid, cricoid, and arytenoid 
cartilages, which may be more or less completely ossified. 
Sometimes an epiglottis is added. 

The voice of Birds, however, is not formed in the larynx, 
but in the syrinx, or lower larynx, which may be developed 
in three positions : — 1. At the bottom of the trachea, from 
the trachea alone. 2. At the junction of the trachea and 
bronchi, and out of both. 3. In the bronchi alone. The 
syrinx may be altogether absent, as in the BaMtoB and the 
CkUhartidce, or American vultures. 

The commonest form of syrinx is the second mentioned 
above, or the broncTio-tracheal syrinx. It is to be met with 
in all our common song birds, but is also completely deve- 
loped in many birds, such as the crows, which have no song. 
In its commonest condition this form of syrinx presents 



314 THE ANATOMY C 

the iollowing characters. The hindermoat rings ol tke 
traciea ooaleace, and form a peculiarly shaped chamber, 
the (tfmpanum. Immediately heyond this, the broncli 
diTCi^e. and fi'om their posterior wall, where one bronchnfl 
paasea into the other, a vertical fold of the lining ruembraiM 
rieea, in the middle line, towards the tjmpunum. ajid forms 
a vertical eepiam, between the anterior apertures of the twu 
bronchi. The witerior edge of this Beptnm is a free a 
thin inemhrana sevdlwuiris, but in its interior a car- 
tilaginous or osseous frame is developed, ajid becomes 
nnitt'd with the tympanum. The base of the frame ii 
hrood, and sends ottt two comua, one along the ventnl, 
and the other along the dorsal, edge of the inner wall tA 
the bronchus of its side ; which, in this part of its extent, 
is membranons and elastic, and receives the name of the 
memhrana tympanifomtis interna. 

The bronchial "rings" opposite this are necessarilj' in- 
complete internally, and have the form of arches embradng 
the outer moiety of the bronchus. The second and third 
of those bronchial arcs are freely moveable, and i " 
tissue accumulated upon their inner surfaces, gives rise to 
a fold of the nmcons membrane, which forms the outer 
boundary of a cleft, bounded, on the inner side, by the ti 
l/rana aem/Uuinaris. The air forced through these two olefU 
from the lungs sets their elastic margins vibrating, end 
thus gives rise to a musical note, the ubaracter of whioli il 
chietly determined by the tension of the elastic marginB bdi 
the length of the tracheal column of air. The nmscles, b, 
the contraction of which these two (actors of the voice an 
modified, are extrinsic and intiinsic. The former ai 
sessed by birds in general, and are usually two pair, pi 
from the trachea to the furcnla and to the ateramn. 
birds possessing a, hroucho-trachcal syrinx such as hat 
described, as the Alectoromorjilta:, Chenomorphfe, and Djl- 
gporvrru/rph^. have no intrinsic muscles. Most others haw 
one pair, attached, one on each side, to the rings of tlie 
trachea above, and to the tympanum, or the proxinul 
bronchial area, below. The majority of the Coraemao^m 



THE BESFIBATOBT OBG&NS IN SAnKOPSIDA. SIS I 



r six pairs of intrinsic ajringeal muscles, which 
pasB from the trachea and its tjmpaniun to the moveable I 
bivmchial arus. The Parrots have no septum, and only I 
three pairB of intrinaic nmaclea. 

The trach£al e^na occurs only in eoiue American Cora- I 
coMuwyfttp, The hinder end of the trachea ia flattened, and J 
a of its ringB above the last are Interrapted at I 
tbe sideH, and held together by a longitudinal iigamentoua I 
band. These rings are eicessivety delicate, so that this J 
part of the trachea ia in great part membranonB. 

The hroncldal ayrinx occurs only in Sleatomis and Croto- 1 
phaga. 

In the genus Cinyiaa, among the Chelonia, and in o 
apeciea of Crouodiiue (C, ocuhw.e.jf.) the trachea is bent upon 
itself. Similar flsEures attain an extraordinary devtilopment 
in many birds, and may lie outside the thorax under tlie in- 
tegument (Tetrao mrogalhiM, some species of Crax, and Pene- 
lope) ; in the cavity of the tborai (aome Spoonbills) ; on the 
est-erior of the sternum (aome Swans and Cranes) ; or even 
in a sort of cup formed by the median process of the 
furcula (the Guinea-fowl). In the Emeu aome of the rings 
of the ti-achea are incomplete in front, and bound the 
apertui-e of an air sac which lies in front of the trachea. 
Some birds {Apteiwd/^lee, Proeellaria) have the trachea 
divided by a longitudinal septum, as in SpkargU among the 
Clielo'iiia, The tracheal tympanum is greatly enlarged in 
Citp'wfcipterus, and in many Ducke, Geese, and Divers ; and 
in these aquatic birds the enlai^ment is more marked in 
the males, and is nsuaOy asymmetrical, the left side being 
generally the larger. 

In the Ophidla, the bronchus opens at once into the lung ; 
and the latter ia an elongated sac, the walls of which are 
produced into numeroos septa, which i-ender the cavity 
highly ceUtilar near the bronchus, while, at the opposite end, 
^tbsy become smooth and but little vascular. In this latter 
□ the lung may receive its blood from the systemic and 
lot from the pulmonary circulation. The lungs are always 
a size, and the left is imually the Huialler. Yery 




31G THE ANATOMY OF VEBTEBEATED ANIMALS. 



frequently, eepeciallj among the poisononB snakes, one lung 
IB mdinientaj'y or altogether abaeat; and the posterior 
portion of the trachea may take on the structure of a lung. 
The lungs of Lizards much reacmblo those of the Ojpladin, 
and tbey are elongated and unequal in aize in the snake- 
like hacertilia. In the ordinary hzards they are more 
rounded and the trachea and bronchi are shorter. In many 
Chanudcons, and in some Geckos, the posterior half of 
each lung is produced into narrow diverticula, which lie 
among the abdominal viscera, and foreshadow the aii' sacs 
of birds. 

In the Orocodilia each bronchus traverses its Inng, and 
at first retains, but soon loses, its cartilaginous rings, 
lateral apertures in the walla of the bronchua lead into 
sacculated ponches^each of which resembles the lung of an 
ordinary Lacertilian, 

The Chelonia have similar lunga ; hut whUe, in the fore- 
going groups, the two Innga are free and iuveeted on all 
sides by the peritoneum, in this they are fixed against the 
inner peiiosteum of the carapace, and are covered bj peri- 
toneum on their ventral face only. This resemblance to 
the arrangement of the lungs in birds is increased by the 
presence of a muscular diaphragm., the fibres of which 
spread over the ventral faces of the hmgs. 

In Avea the lungs are firmly fixed on each side of the 
vertebral column, the dorsal surface of each lung being 
moulded to the superj acent vertebne and ribs. The muBCoIar 
fibres of the diaphragm arise from the ribs outside the 
margins of the lungs, and from the vertebral cotunm, and 
end in an aponeurosis upon the ventral surface of the 

Each bronchus enters its lung nearer the centre than 
the anterior edge ; and, immediately losing its cartilaginous 
or bony rings, dilates, and then traverses the lung, gradually 
narrowing, to the posterior edge of that viscus, where it 
terminates by opening into the posterior air sac, which 
generally lies in the abdomen. From the inner side of the 
bronchus canals are given off, one near its disttkl °^^^^ >W^. i 



otliors near its entrance into the lung, which pass directly 
to th(! ventral aurfaco of the lung, and there open into other 
air sacs. Of these there are four. Two, the anferiiw and the 
posterior thoracic, lie on the ventral face of the lung in the 
thorax. The other two are situated in front of ita antt'rior 
end, and are eitra-thoiucic. The external and superior is 
the ceniieal, the internal and inferior, the inteyelavicuhir. 
This last unites into one cavitj with its fellow of the oppo- 
site lung. Thus there are altogether nine air aoca i two 
poflterior or abdominal, four thoracic, two cervical, and 
one interclaTicular, Other large canals given off from the 
bi-onchua do not end in air-aace, but those which pass from 
the inner aide of the bronchua, ran along the ventral sur- 
face, and those on the outer side, along the dorsal surface, 
of the lung. Here they give off. at rig-ht angles, series of 
eecondary canals, and these similarly emit stOl smaller ter- 
tiary caDals ; and thus the whole eubetonce of the lung he- 
onmea interpenetrated by tubtili, the walls of the finest of 
which are minutely sacculated. The different systoma of 
tubiili are placed in communication by perforations in their 

In most birds, the air-saca (except the anterior and pos- 
terior thoracic, which never communicate with any cavity 
but that of the limgs) are in connection with a more or leas 
extensively ramified system of air passages, which may ex- 1 
t«nd through a great many of the bones, and even give offl 
Bubcutaneous sacs. Thus the inten-la,vicular atr-sao gene- I 
rally sends a prolongation into each axilla, which opena J 
into the proximal end of the humeiTia, and causes the 1 
cavity of that bone to be full of air. When the sternum, 4 
the riba, and the bones of tlie pectoral girdle are pneumatic, .1 
they also receive their air from the interclavicular air-eaca. I 
The cervical air-aaca may send prolongations along the ver- I 
tebral canal of each aide, which supply the bodies of the •% 
cervical vertebras, and communicate with elongated air- J 
chambers in the spinal canal itself. When the dorsal ver- ] 
tebrse are pneumatic, they communicate with the system of ■ 
the cervical air-aaca. The abdominal air-saca send prp-J 



f VEKTEBRATED ANIMALS. 

longations above the kidneys to the sacral vertebne and 
to the femora, whence theao bones, wLen they are pneit' 
matic, receive theu" air. 

The pulmonary air-aacB and their prolongations do not 
comnmnicate with the air cavitiee of the aknll, which re- 
ceive their air from the tympana and tbe nasal chambers. 
In Bome birda, the air ia conducted from tbe tympanmn 
to the articular piece of the mandible by a special bonj 
tube, the siphoniwn. 

In all Saiiropsida, the uretera open directly into the 
cloaca, whicli is provided with a urinary bladder in tie 
JjacertUia and the Chelonia, hut not in other BcpitJia, nor is 
Avea. 

Organs of copulation present themBelves under three 

1. In the Clidonia, the Crocodilia, and the Ostrich, > 
simple solid penis, grooved upon its jwsterior aspect, is at- 
tached to the anterior wall of the cloaca, and contains 
erectile tissue. In the ostrich this penis lies in a sac of tk 
cloa:Ca, into which it can be retracted somewhat as in the 
Menoiremata. 

2. In many birds, such as the Rheida:, Ceuaaridit, 
Apteryffidte, Timammnorphm ; Penelope, and Crof-, among flw 
AlectoromwphfB ; and in many aquatic birds, there is also 
a single penis attached to the front wall of the cloa«, 
grooved on its doraal aide, and supported by two fibrtiiu 
bodies coated with more or less erectile tissue. But the 
distal end of the penia ia invaginated, and the involution 
held in thia position, except duiing erection, by an elastic 



In Lacertilia and Ophidia, two coptdatory organs are 
developed at the aides of the cloaca. The integument u 
prolonged jnwarda, on each side, into a bhnd sac, whidi 
lies upon the inferior caudal muscles. The inner mntace 
is often armed with spiny developmenta of the epidermis, 
and presents a groove, which is continued on the pariet« 
of the cloaca to the aperture o( the raa deferens. The 
wall of the blind aac contains erectUe tissue, and it "•>" be 
j^rected or reti-acted by appropriate musclee. 



319 



t 

i 

CHAPTER YIIL 

THE CLASSIFICATION AND ORGANIZATION OF THE 

MAMMALIA. 

The class Mammalia is divisible into the following 
groups : — 

A. There are large and distinct coracoid bones, which articulate 
with the sternum. 

The ureters and the genital ducts open into a cloaca, into 
which the urinary bladder has a separate opening. 

The penis is traversed by an urethral canal which opens into 
the cloaca posteriorly, and is not continuous with the cystic 
urethra. 

There is no vagina. 

The mammary glands have no teats. 

I. Ornithodelphia. 

1. Monotremata, 

B. The coracoid bones are mere processes of the scapula in the adult, 
and do not articulate with the sternum. 

The ureters open into the bladder ; the genital ducts, into an 

urethra or vagina. 
The cystic urethra is continuous with the urethral canal of 

the penis. 
There is a single or a double vagina. 
The mammary glands have teats. 

A. The embryo does not become connected with the 

wall of the uterus by an allantoic placenta. The 
vagina is double. 

II. DlIilXPHIA. 

2. Marsupicdia, 

B. The embryo has an allantoic placenta. The vagina 

is single. 

III. — MOMODELPHIA.'l' 

a. Median incisor teeth are never developed in either jaw. 

* The manner in which the Monodelphia are here subdivided must 
be regarded as merely provisional. 



' TEaTEBRATED ANIHAI^ 



ediaii 


bod 


or teeth are 


aim 


Bt alwaj 




The 


4 
B 


derelopes n 
Ungulata. 

Siroiia (?) 
Crtacfa. 


odo 


idutt(jVo 


i-iK^iAialo). 


The 






decidua Cn-c 


i/uBfa). 


a. Th 


•"; 




J- 










Probotriilira. 










Camkom. 








$. ThepiHceDtBiBdiBc 


idal. 








11 


Hodentia. 










la 












13 












14 


Primata. 









I. The ObnithodelphiA axe tliose mammals wluei 
approacli nearest to the Bavropaida, althoiigh separated 
from them by all the eaaential characters o£ the MamTnalio 
which have already heeu defined. 

The two genera Echid/iia and Ormitkarynchvs, whicli eoa- 
stitute this diyiaion, agree with one another, and differ from 
all other Mammals, in the combination of the following 
characters: — 

In tiie spinal colnmn, the centra of the vertebrae are 
devoid of epiphyaeB. The os oHontoidewm, or ao-caHed 
" odontoid procesB " of the second cervical vertebra remaiiu 
for a long time, if not througbont life, nnanlijlosed witli 
the body of that vei-tebra, as is the case in many Reptiles. 
And Bome of the ceiTical ribs, in like manner, long persist 
in a separate condition. 

A atriiing Sanropsidan and Amphibian feature, peculiar 
to the Omithodelpkia, is seen in the fact that the coracoid. 
which IB a large bone, articulates with the sternum directly. 
In front of it is another conaidenible ossification called the 
epieoracoid, which corresponds in position, though not in 
the manner of its ossification, with the ossified cartilage so 
termed in i-eptiles. In these manunala alone, again, there 
ia a T-shaped interclavicle, which stipportfi the claTiclee. 

*' The plu«ntatiaa of tho Toiodoatia and Sircnia U onLnown. 



THE OBNITHODELPHIA. 



321 



e central portion of the acetabulum remainB unoBsified, 
lud hence, in the dry Bkeleton, appears perforated, aa in 
I, OmithoBoelida, and Crocodilia. 

The inner tendons of the external oblique muscles are . 
saified for a considerable dietance; and these ossificatioaB I 
Appear in the dry skeleton as bones, which are articulated I 
■with the inner portions of the anterior margins of each 1 
pubis. These hones correspond with those which eiiat in I 
a. Like position in the Videlpkia, and are called marsupial I 
bones i though the term is peculiarly inappropriate, i 
much as they have nothing to do with the marBvpiwrn, I 
or pouch, in which the young are sheltered in most of the | 
JXdelphia. 

In the upper view of the brain the cerebellum is left J 
completely imcovered hy the cerebral hemispheres. Th& 1 
latter are connected by only a. very small corpus callosum. I 
The anterior eomnjiaaure, unlike that of any of the Sawop- 
sida, attains a very great size, and the hippocampal sulcus 
is prolonged forwards to the corpus caUosum. 

In the internal ear, the cochlea is only slightly bent upon 
itself, not coiled into a, spiral, ax in other Mainmalia. The 
stapes is imperforate and columelliform, and the malleus is- J 
very large, while the incus is singularly small. 

There is a. spacious cloaca common to the rectum, genital l 
and urinary organs, as in the Saiiropsida and many Ickthy- 
opidda. In both sexes a long urogenital canal opens into 
the front port of the cloaca. At its anterior end there are 
five distinct apertures — one in the middle line for the 
bladder, and two on each side, which are the openings of 
the genital ducts and of the ureters. Thus in these JftuH- ' 
malia, and in theee only, the ureters do not open into the I 
urinary bladder. The testes remain in the abdomen through- 
out life. The penis is attached to the front wall of the ■\ 
cloaca, and is not united directly with the ischia, I 
traversed by an urethral canal, which opens into the cloaca 
posteriorly, but is not directly connected with either the 
aeminal or the urinajy passages. It is probable that during 
copulation, the posterior aperture of the penial urethra is 



322 THE 4NAT0HY OF VBBTEBB*.TSD J 

applied to the anterior aperture of tbe urogenital canal, bo 
aa to form a continuoua pa.asage for the semen. 

The ova of the female are Terj largu and project from the 
aurf ace of the ovary, as in the Saitre^iida. The mouths of 
the Fallopian tubes are not fimbriated. There is no Taguu 
distinct from the urogenital chamber. The manaaiaj 
glands are situated, one upon each side uf the middle line. 
in the hinder part of the abdominal walL 
duota of the gland open upon a smalt area of the integu- 
ment which is not raised up into a teat, ao that, in the 
strict etymological sense of the word, these ajiimala a 
Jfammalia. The mammary gland is compressed by the 
pannicuhis caraosas, and not by any prolongation of tlie 
cremaster. 

There is no aufficient evidence of the nature of the fcetal 
appendages; hut the embryo is born in an imperfect o 
dition, and may be provided with a knob or caa"uncle upon 
the premaiilke, such as is found in the Sauropaida. In the 
adult the heart exhibits a/o88o ovaUs. 

Both genera of the Omithodelphia are restricted to Aus- 
tralia, including Tasmania under that na 

The one of them, Echtdna, has the body covered with 
spines, like a porcupine. It possesses strong digging feet, 
and a nai-row toothless mouth, fiom which the long ton|fne, 
with which it licks up the ants upon which it preys, i 
protruded. 

The other genus, OmitharhynehTit. has soft fur ; a flattened 
muzzle resembling the beak of a duck, and covered with a 
leathery integument; and clawed, but sti-ongly webbed feet, 
fitting it for its aitogether aqnatic mode of life. The Omi- 
thorhynchug, in fact, frequents fresh water pools and rivers 
very much like a wuter rat. eleepiug and breeding in 
burrows excavated in the bank. 

In these animals the angle of the mandible is not in- 
flected. They ai'e devoid of any external ear ; and ia the 
males, a kind of spur, which is perforated, and gives exit to 
the secretion of a gland, is attached to the astragalus, 
function of thia organ is unkiiuwu. In each getnu 



luB. I^^ 



THE DIDELPHIA. 

heai-t is provided with two superior caTte. In Echid/na the 
right aoriculo-Tentricle valve in membranone, bnt, i 
nithoThyiichuB, it is more or less fleshj^. 

The hemispheres of the brain are abundantly convolnted 1 
in Echidna, but are emooth in OrniihorhynehuB. The I 
ovaries are of equal eize in Eclddma ; but, in Omitliorhynchua, | 
the right is much smaller than the left, as in Birds, As j 
has already been stated, Echidiui is entirely devoid of teeth, 
while Omii}it)rhynchii4 has four large homy teeth. 

II. The DiDBLPHiA. — In the Bidelphia, the " odontoid J 
proceas" early becomes completely ankylosed with the body ( 
of the second vertebra ; and, usually, all the cervical ribs I 
speedily lose their dietinctnesB, as in Mammala in general. 

The coracoid is reduced to a mere process of the scapula 
and does not come near the etemum. Tiiere is i 
coracoid, snch as eiiste in the Omithodelpkia. Ther 
X-shaped interdavicle, but the clavicles, which are always 
present (except in PeramoIeB) artiouhLte with the manu- 
brium of the sternum, in the same way as in ordinary Mam- ', 
inalia. The floors of the acetabula are completely oaaified, I 
and consequently are impei-forato in the dry eteleton. The 1 
cochlea is coiled upon itself. 

There is a shallow cloaca, the sphincter muscle beingf ] 
common to the urinary and genital apertures, but there is 
no such urogenital chamber as in the MarwtFmrutta, The | 
ureters open directly into the bladder. 

In the male, the urogenital part of the urethra, snd that 1 
which traverses the penis, form one continuous canal, which | 
opens ontwards only at th.e oitremity of the penis. 

In the female, the vaginal, is perfectly distinct from the I 
urinary, passage. The mouths of the Fallopian tubes are I 
fimbriated, and the ova are not larger than those of the I 
Moiu>delpkia. 

The mammary glands are provided with !ong teats. 

I In aU the preceding characters the Didelphia, agree with 1 
e Monodnlphia, and differ from the Omithodelpkia 
But they agree with, the OmiUhodelphia, and differ from; J 



324 THE ANATOMY OF YEBTEBBATED ANIMALS. 

the Monodelphia in possessing either bones, or cartilages, 
attached to the pubes, in the position of the so-called 
marsupial bones of the Omithodelphia. 

Again, the brain, the cerebral hemispheres of which may 
or may not have a convoluted surface, is provided with a 
very small corpus callosum, and a large anterior com- 
missure. The hippocampal sulcus is prolonged forwards 
over the corpus callosum. 

The crura of the corpus cavemosum of the penis are not 
fixed to the ischium. 

The embryo does not become connected with the parent by 
villi developed from the aUantois, and it is bom in a very 
imperfect condition. 

Certain characters are peculiar to the Didelphia. Thus, 
the testes of the male pass into a scrotum, which is sus- 
pended in front of the penis. In the female, the cremaster 
muscle is largely developed, and spreads over the surface of 
the mammary gland, which it compresses, so as to drive 
the milk out of the projecting teat. There is no fossa 
ovalis on the right side of the septum of the auricles. 
Very generally, though not invariably, the Didelphia possess 
what is termed a marsupial pouch, which is a sort of bag, 
formed by a fold of the integument of the abdomen, into 
which muscular fibres of the panniculus carnosus extend. 
These support the ventral wall of the pouch, and are 
capable of closing its mouth, which may be directed either 
forwards or backwards. The mammary glands lie in the 
dorsal wall of this pouch, into which the teats project. 

There is no direct communication between the female 
generative organs and the pouch ; but the minute young 
are transported, in the blind and imperfect state in which 
they are bom, into the interior of the marsupium, and each 
becomes attached to a nipple, which exactly fills its mouth. 
To this it remains attached for a considerable period, the 
milk being forced down its throat by the contraction of the 
cremaster muscle. The danger of suffocation is averted 
by the elongated and conical form of the upper extremity 
of the larynx, which is embraced by the soft palate, as in 



THE DIDELPHI4. 



3 Cetacea ; Brad thua i-espiration goes on fi'eely, while 
ses, on ea«li side of the larjngeul cone, into 

aoph^us. 
t It vei^ commonly happens among the Didel^hia that the 

o long vaginee are bent upon themaelyeB, their proximal 
IQdB becoming applied together and dilated, and these 

lated portions not nnfrequently communicate. Another 
y general peculiarity of the Didelphia is the inflection 
E the lower margin of the angle ot the mandible inwards 
into a strong horizontal process. In the genus Taraipi 
however, this process is absent. 

There are further anatomical characters which are 
worthy of notice, though they are not so important aa 
foregoing. 

The integument is always furry, never spiny or scaly, nor 
provided with dermal seutes. The pinna of the external 
ear is well developed. In the Hkull the carotid arteriea 
pierce the basiaphenoid to enter the cranial cavity, 
tympanic cavity ia, in front, bounded by the aliaphenoidj 
and. very generally, the jugal furnishes part of the arti( 
surface for the mandible. 

Many of the cranial sutures, especially in the occipil 
region, persist throughout life; and the squamosal, 
united periotic oBsifications, and the tympanic I 
distinct from one another. 

The Jaws are always provided with true teeth 
nsually, these teeth are readily diatinguiahod into in 
canines, false molars, and true molars. The canines, hoi 
ever, are absent in aome genera, either in both jaws 
the mandible. There are usually four true molar 
and, as Professor Flower has recently discovei'ed, only oi 
grinder aucceeda another vertieaOy. It represents the li 
premolar. The molars never possess a complex structure. 

No didelphotis mammal has three incisor teeth upon ei 
side above and below ; and none but Phascolmnyg has 
equal number of inciaora in each jaw, the number of 
upper being, usually, in eicess of that of the lower jaw. 

The number of the dorao-lonLbar vertebne is ahn^ 



I 



326 THE 

alwajrs nineteen ; and, of tbeae, six are UBiiailj doraaL The 
atlas is generaliy inciompletely osaified 
median line, TUe tnanus naually poaseaaea five digite, bnt 
in Feratnales and ChcEropat the outer digits become mo- 
mentary. 

The fibula is always complete at its distal end. In h 
cases it becomes ankyloscd with the tibia, while in 
Wombat [Pkascolomys), the Phalangers iFlialangigtida), and 
tlie OposBUms (Dide^kidce), it is not onlyfrec, but is capable 
of a rotatory movement upon the tibia, similar to the move- 
ment of pronation and supination of the radius npon tbe 
nlna in Man. The rotation of the fibula towards the ventral 
side of the tibia is effected by a muscle which, in great 
measure, occupies the place of the interosaeouB ligajnont, 
and is analogous to the pronator quadratus in the fore limb. 
This muscle is antagoniaed by the extensors of the digiU, 
BO far as they arise from the fibula. 

The digits of the pea Taiy remarkably in their form and 
relative development among the MareupMia ; the different 
aubdivisiona of tbe order being very well distinguished by 
the modifications of the hind foot. 

Thus in the eapeeially carnivorous marsupials— the Didd- 
phidm, of America, and the Datyvridie, of the Auatralian 
province — the second and third digits of the pes are not 
united together by the integument. In the Didelphidm, ttid 
hallux is niul-lesa, but large and opposable, so as to convert 
the pes into a prebenaile organ like that of many Primaiet; 
in the Dasyuridas. on the other hand, tbe hallux ia rudi- 
mentary or absent. In all tbe other marsupials, the second 
and tbii'd digits of the pes are ayndactyle, or united togetliex 
by integument. In the Wombat, the fourth toe is bonnil 
together with the other two, and the small baUux is devoid 
of a nail. In the Fhalangers, only the second and third 
toes are syndaetyle, and they ai-c slender, compared with. 
the other digits, while the hallux is well developed and 
opposable. In the Permiielidm (.Bandicoots) and Macro- 
podidm (Kangaroos), the m.etatarauB is much elongated, aod 
the second and third digits united and slender, while the 



THE DIDELFHIA. 337 I 

is very large. The hallux is reduced to its I 
letatarsal bone in the PeraainUdiE. and the fifth digit is ■ I 
r rudimentarf. In the £angaj-aos, the hallux dis- I 
(ppears altogether, hut the fifth digit remuina well da- 1 
eloped, though not bo large as the fourth. 1 

I There is a great range of variation in the characters . 

the hrain. The camiTOi'ous marsupiiLlB {Didelpkys, 

iaity^intB, Thylacin/us) exhibit the lowest tjpe of cerebral 

factnre, the olfactory lobes being very large and com- 

_ letely exposed, ■while the cerebral hemispheres are com.- 

Kparatively Hmull and quite smooth. In the Eangaroos, on J 

■ tiie other hand, the cerebral hemiBpheres present nnmerouK I 

r convolutions and are much larger in proportion to tbd I 

olfactoiy lobes, which they cover. I 

The stomach may be simple, as in most Marmtpialia, or I 

provided with a cardiac gland (PhancolaTcioM, Phaacolo7H/ya). 1 

In the Kangaroos, it becomes immensely elongated, with. ■ 

longitudinal muacolar hands and transverse sacculationa. ,1 

BO_that it resembles the human colon. The ccecum, which i» j 

large in the Kangaroos, but absent in the DasyvriAcB. i*>l 

provided, in the Wombat, with a venniform appendix lilca^ 

that of Man. fl 

The liver always possesses a gall-blaflder. There are twojH 

iMJKE cavcB aupenores, and they receive the vence axygos (^S 

their respective sides. The tricuspid valve in the heart UTm 

membranous. There is no inferior mesenteric artery, and I 

the external and internal iliacs arise separately fixim the I 

There are no vesicuhe seminales, and the glans penis i» 1 
biforcated in many species. The marsupial pouch is absent ■ 
in some Opossums and DasywridtE. When it is present, its I 
mouth is usually directed forwards, but in Tltylaa.nM and I 
in some Perainelidm it looks backwards. In Thylannus aSao I 
the " muTBupial bones" I'cmain cartilaginous. The con- I 
dition of the fffitus is known only in the Kangaroos, and I 
fni-ther observations on the eiubryotogy of the IMdelphia 1 
are much needed. The fcetus is said to possess a lat^.fl 
umbilical sac, the vessels of which extend on to the plaitejj 



3'28 THE ANATOMI OP 

chorion ; and a. small aUantotE ; and to be devoid of a. thyma 

The IHdelphia ore at present confined to the AuBtndiai 
find the AuBtro-ColtunbiBji provinces, some few speciet 
stretching beyond the borders of the latter into the aorthHi 
parts of Sorth America. The Didelphidte alone arc found 
in Austro-Coliiuibia, all the other groups being Anstraliiui. I 

Gigantic, Kangai-oo-liie, or Phalangistic, forma (WirfolV- I 
riwwt, JWyroioA™, 11 j/iacoifio), have been found in post- tertiar) 
deposits and caves in Anstralia. In Europe, IHdelphiia 
occur in Socene strata.; IHde^hidce, Datyn/ridte, and Jfn- 
rropodidae (FhagcolotheriKm, AmphUheriuw, Ptagiaulcai}. i 
middle Hesozoic rocks ; and Maeropodida (?) (MicroleeUi) in 
the Trias. 

m. The MoNODBLPHiA. — In the Jtfonodelphia 
odoataidev/in very soon becouiea anfcyloaed with the second 
cerrica] vertebra, of which it appears merely as the odontoid 
process; and the cerrical ribs early beconie inseparably 
united with, their vertebrffi. The coraeoid is reduced to a 
mere process of the scapnla, and there is no epicoraooid 
similar to that of the OridthodelpliM 

Claviclea may be 'present or absent. When completelr 
developed they articulate directly, or by the int«rmediatiyn 
of more or lees modified remains of the sternal end of the 
coraeoid, with the sternum, and not with any iuterclavicle. 
The acetabula are imperforate. The pelvis is devoid of 
marsupial bones ; though, in some Camivora, there are small 
cartilages in the inner tendons of the eKtemal obUque 
muscle, which have a correspoDding form and relations. 

The anterior commissure and thecorpns callosuni, no less 
than the cerebral hemiaphercH themselves, vary greatly, the 
braina of aome Edentata very closely approaching those of 
the Didelphia in respect of the corpus callosum and an- 
terior commissure; while, as regards the hemispheres 
themselves, they may either be so smaU as to allow the cere- 
bellum to be completely exposed on the dorsal aspect, or so 
large, as completely to cover it and project beyond it. Thc 



r 



HUE UONODfiLPHIA. 



external aurface of the hemisplierea again, may be either 
perfectly aniooth. or citremely convoluted. 

The cochlea lb coiled spirally. The reprodnctive and 
nrinary apertiirea, as a general rule, open qnite separately '■ 
from the rectum. The ureters always open into the bladder. ¥ 
The testes may remain in the abdomen throughout lifsi I 
or may pass into a scrotal pouch. But, when this Bcrotmn I 
forms a distinct sac, it lies at the sides of, or behind, the 1 
penis, and not in front of it. The cystic urethra is always I 
continuoas with that part of the uretkra which ti-averses 
the penis. 

The ova are small, and the mouths of the Fallopian tubes 
ore fimbriated. The vagina is a, single tube, which miiy 
however be partially divided by a longitudinal partition. 
The cremaster has no relation to the mammary glands, 
Arhich are provided with distinct teats. 

The allantois is always well developed, and gives rise to a 
placenta; and the yoimg are bom of large size, and . 
active. I 

The great majority of the Monodelpkia, as thus defined, '. 
are divisible according to the characters of their placenta 
into tum-d^cidaata and dedduata. 

In the non-decidnata the fretal villi of the placenta are, 
at birth, simply withdrawn from the uterine foaste, into 
which thej are received, and no part of the maternal 
substance ie thrown off in t^e form of decidua, or maternal 
part of the placenta. In the deciduata, on the other hand, 
the superficial layer of the mucous membrane of the utems 
undergoes a special modification, and unites, to a greater i 
or less extent, with the villi developed from the chorion 
of the fcstus ; and, at birth, this decidual and mate 
part of the placenta is thrown off along with the ftetus, ] 
the mucous membnuie of the uterus of the parent being I 
regenerated during, and aft«r, each pregnancy. 

There are, however, two orders of existing monodelphot 
Mammalia, the natnre of the placentation of which is n< 
yet fully madn out. One of these is the Sirenia, the pla- 
oentation of whioh is unknowiu The other is the ill-de&ied J 



330 THE ANATOMT OP TEKTEBEATED ANIMALS. 

and heterogeneouB asaeiabluge called Edentata. Some ol 
the members of this gronp certainly poBseaa decidnate pl>- 
centsB, wtile, in others, it appears questionable whethr 
the deeidna is, or ia not, developed. Aad as this gnraf. 
the Edentata, ib decidedly the lowest of the whole diTiaion, I 
Hhall take it firat in order, while the Sirenia are arrangei 
proviaionally, among the Non-di!cid\iata. 

The Edentata, or Bkuta, — In these ManimalB tin 
teeth ai-e hy no means always wanting, as the name o( tii 
gronp would seem to imply ; but, when teeth are preeeiA 
inciaora are either idtogether abaent, or, at any rate, tin 
median inciaora are wanting in both jaws. The teeth 
always devoid of enamel, consisting merely of dentine mi 
cement. As they grow for aa indefinite period they 
form roota; and, ao far as our knowledge at presenl 
eitendH, thoae which first appear are displsiced by % 
second set only in some of the ArmadilJos. The nngtul 
phalanges of the digits support long and atrong claws. 

There are maramse upon the thorax, and aometimes, in 
addition, on the integument of the abdomen ; or, in tie 
inguinal region. 

The bi-ain varies greatly, its hemispheres being some- 
times quite amooth, with a veiy small corjius callosum and 
large anteiior commiaaare ; while, in other cases, the cor- 
pus callosum is much larger, and convolutions appear npon 
the surface of the brain. 

The Edentata are divided into the Phytophaga, or vege- 
table feeders, and the Entomopjiaga, or insect- eating fonm. 
leaves are the chief food of the former group, while tlu 
latter delight chiefly in anta, though some take, in additjooi 

1. In the Phytophaga the long hones are witbont me- 
dullaiy cavities. The lateral part of the zygomatdo arch 
Bends down a romarfcable vertical procesa. The acromial 
process of the scapula coaleaces with the coracoid. In the 
carpus, the scaphoid and the trapezia! hones ankylose and 
form one. The iacliia become united with the 



.ndal vertebne, and these ankjloae with the proper aacral» I 
I form the long aacnim. 
The anTila joint has the character of a peg and socket J 
id the hind foot ia, more or lese completely twisted, I'eat* I 
,g upon ita outer edge, and not upon its sole. 
Vaacular canals connected with the pulp cavity traver 
le dentine of the teeth. 

The Fhytophaga are divisible into two groups, t 
ig, aiid the other extinct. The former consists of tha| 
btha, or Tardigrada; remarkable animals, which are ci 
ned to the great foresta of South America, where th^J 
ad a purelj arboreal life, suspended by their strong, hook-fl 
ke, clawB to the branches of the trees. 
Their dietinctive charactera are theae : — The tail is ahort, 
id the limba exceedingly long and alender, the anterior, 
longer than the poaterior, pah-. In both the fore and 
le hind limba the internal and the extei-nal digits are 
idimentary, but the hind foot always baa the three middle J 
es completely developed ; while, in. the fore foot, it s< 
mcB happens that only two remain. The ungual pho* 
ngea are very long and hooked. 
The y.ygomatio arch ia incomplete poateiiorly, not b 
united by bone with the aquamoaal. The cervical vertebra 
in thia remarkable group eometimea exceed, and aometimeS 
fail short of, the number (aeven) which ia so characteristii 
of the Maminalia in general ; some apeciea of Sloths havii 
nine, and others only six, vertebrte in the neck. 

The pelvis ia exceedingly spacious, and the acetabula a 
directed backwards as well as outwards. The femur ii 
void uf a ligameiilvm terei. The distal end of the fibul 
sends inwards a process which fits into a fossit situated 
upon the outer suiface of the astragalus, giving rise to thsbj] 
kind of peg and socketankle-joiutwhioh ispeeuUai' tothea 

A good deal of confusion prevails respecting the structui 
I ctf the ankle-joint in the Sloths. Cuvier (' Ossemens fosaile8,'i| 
viii. p. 143), writes of the Ai, or three-toed Sloth : 
" In the greater number of aniiuals, the principal articib 



? TEBTEBRATED AHIHAI^. 

lation of the astragaliiB conneivta it with the tibia. bjmeuB 
of a more or ieaa loose gingljmua, which allowe the foott* 
be bent on the leg. But here the principal and Bnperiu 
facet of the aatr^;alu8 is a coucal fosaa, into which li: 
pointed extremity of die fibula penetratee, like a pit* 
(See PI, 208, fig. 2a.) The inner edge of this foBsa tunii 
agninat a very Hmall facet, which ocoupiea only a third li 
the lower head of the tibia. The result of this arrange 
ment is that the foot turns on the leg. like a wealheroxk 
on its support, but that it cannot be Sexed. It furth* 
follows that the plane of the Bole of the foot* ia alraoK 
vertical when the leg ia so, and that the animal can oiilj 
place the plaatar surface of its foot on the groiuid Ij 
apreading out the leg bo aa to make it almost horizontaL" 

Meckel.t has already justly remonstrated agaixiHt CnTira'i 
aasei'tioa that only ahduotion and adduction are poaaiblt 
to the pea of the Ai. affirming that it is capable 
and eitenaion, though only to a limited extent. J 
follows Meckel, but Rapp (' Edentaten,' p. 46) adopt" 
Ottvier'a atatement in its fulness: " Extension and fieiiw 
of the foot cannot take place, but only abdnctiou and 
adduction." However, it is easy to demonstrate c 
uninjured dead animal, or still better, on the limb trDO 
which the muscles have been removed, while the ligamenb 
have been left intact, that the pes of the three-toed Slolh 
is capable of eitensive motion in three directioiiB; lst,iD 
abduclJon and adduction ; a movement in azimuth, when 
the leg is vertical ; 2ndly, in flexion and extenaion ; a mott 
extensive movement in altitude, under the same cir 
atancea ; and 3rdly, in rotation upon its own axis, by u 
of which the sole can be moved through 90° from a pos 
perpendicular to the axis of the leg to one parallel with it 

The anatomical arrangements upon which the eseontiOB 
of these movements depend are the following. The aatnt|^ 

* Cuvier's ffords are : " II en nSsnlte enoora quo le plui, le cofpi *i 
pied, est presqufl vertical quand la jambe I'eal." 

t 'Syatem der verglelchenden Auatomio,' Ste Theil,, Ste AUfed- 



THE ANKLE-JOINT OF THE SLOTH! 

8 presents two facets to the bonea of the leg, one of which J 
a tie pes is in the position usuiU in other quadrupeds) I 
(oke inwards and upwards, while the other lookB outward^ ] 
jid upwards. The former, convei from before backwarda, 
f AS well as from side t« side, is bj no means a mere rim, 1 
^ough it is not so wide as the other. It is the propei* 
posimal surface of the aatragalua, and articulates with the 
The other surface is eicavated by a deep conical pit- 
^to this is received a correspondingly conical process of 
e distal end of the fibula, which is directed from above 
without, downwards and inwards — not vertically, there- ■ 
!, but very obliquely. Hence, even if the pivot fitted I 
s socket qnite accurately, there would still be abundant 
^portnnity for flexion and eitcnaion, though the movement 
i the pes would be obliquely inwards, as well as upwards, in 
ler case ; and obliquely outwards, as well as down- 
irds, in the latter. But the socket fits the pivot loosely, 
and hence, as experiment demonstrates, the movement 
of the pee in flexion and extension is hut very slightly 
oblique. 

The tme movement of abduction and adduction is bo 
much less extensive than the movement in flexion and 
extension, because it is checked by the short and strong 
internal and external lateral ligaments of the ankle-joint. 

With respect to the rotation of the foot on its own axis- 
it is to be observed, in the first place, that the ealfan^uiiih'l 
ciiboidus, namcvJare, the three aineiformia, the thi-ee c 
plete and the three rudimentary metatarsals, and the thros.'J 
basal phalanges of digits it., Hi., and iv., are anfeylosed to- W 
gether into one bony mass; while, as in the manus, therft^] 
ia hardly any motion between the basal and the middle,] 
phalanges. Practically, in fact, the only bonea of the pea T 
which are movable upon one another are: 1. The distal I 
phalanges, which have a movement of extension and flexion | 
through ISC' upon the middle phalanges, 2. The tarso- 
phalangeal synostosis above described ia freely movable 
the astragalus; and the joint ia disposed in such a 
m to allow the sole of the foot to be rotated from the 



334 THE ANATOMY OF VEETBBBATED ANIMALS. 



plantigrade i>ositioti in wliicli it is perpendicnLir tfl flu 
axiB of the leg, to the Hcanaorial position, in wbich it lia 
parallel with the axis of tlie leg. It may be douhted, hw- 
ever, whether the furmer position can be given to the M^ 
bj the living animal. The UbiMtis aaticua and the taiaiti 
hallvcU Umgas are estremelj atrong moscloe, and hftve M 
efficient aalagoniats; so tliat their tonic contraction nud 
pull the navicular metatarsal tuberosity into which Ihejaw 
inserted as far npwarda as it will go, causing tbe tor» 
phalangeal aynostosiB to rotate upon the astragalos. aal 
thns obliging the sole of the foot to look inwards. 

In the two-toed Sloth, or TJnau {C/wttepus), tbe 
Btmcture of tbe ankle-joint is tbe same, but tbe focsa of 
the astragalus loolifi almost dii-ecUy outwards, and tbe pirol 
of tbe fibula is more nearly horizontal, when the leg ' 
vertical. The tibial facet of the astragalnB looka directlj 
upwards. Hence, tbe movement of the pes is more ei- 
clusively one of flexion and extension than in tbe AL No 
ankylosis of tbe tarsal, metatarsal, and phalangeal bones 
occurs, but tbe rotation of the distal moiety of the taraiu 
upon tbe astragalus is much more complete and permanent 
than in the Ai. The calcaneuni is twisted round under tlie 
astragalus, in such a manner that its proper external too) 
becomes inferior, while tbe ai'ticular surface for tbe cnboid 
is not only below, but is partially internal to, tbe navicnkt 
facet of the astragalus. As a result of this position of the 
cuboid, the outer metatarBals, which it supports, are plaicei 
directly beneath the inner ones, and tbe pea rests absolute 
upon its outer edge, the plane of tbe sole being vertieaL 

The Sloths, it thus appears, are naturally club-footed; 
but neither in the Ai, nor in the Unau, doea tbia depend in 
any way on the structure of the ankle-joint. On the con- 
trary, it results, in tbe Unau, from the manner in whid 
the calcaneum and navieitlare articulate with the aatragalusi 
and, in tbe Ai, from the action of tbe muscles on the tarao- 
pholangeal synostosis. Neither in the Ai, nor the Unan. 
is there anything to interfere with free flexion and extea- 



THE EDEKTATA EKTOUOPHAOA. 335 il 

The teeth, are five in nnmber on each side above, snd 
T below, and become Bhajpeaed bj mntiukl attrition into 
I chisel-like form. The etomach ia reroarkablj complex. 
The Oravigrada are, for the most part, like the Sloths, 
inth Americaa forms, but thej are entirely extinct ; and 
rliile, in most respects, tbej resemble the Sloths, in others 
y present an approximation to Ant-eat«r8. 
The jngal arch may be complete or incomplete. The 
iticular anrfacea of the dorsal vertebra; are Bometimee 
iomplicated in a, manner similar to that observed in the 
■nt-eatere. The tail is very long and strong. The limbs 
re short and sub-equal, while the fore foot has the ulnar 
digit imperfect, as in the Ant-eaters. The fibula ha« 
so inward process, and the astragalus is consetjiicntly de«v 
TOid of any fossa upon its outer surface. Bu 
*Mnd of peg and socket ankle-joint is produced by t 
interlocking of the surfaces of the tibia and of the a 

e great extinct animala, Megatherium, Mylodon. i 
gattmyx, &c., the remains of which have been found abni 
'wholly in later tertiary deposits of America, belong to 

2. The Byitomopkaga. — In this group of Edentata the zyJ 
. goraa sends down no process from its lateral region? 
although, in some rare cases, the anterior part of the arch 
3, descending prolongation. The acromion and the 
coracoid do not become united. The scaphoid and the 
zium remain distinct ; and the sole of tht hind foot 
rests upon the ground by a greater or lesser extent of 
Tvhole surface, and not merely by its outer edge. 

The insectivorouB edentates are divisible into four grouj 
— a. the Mutiea, b. the Sqvamata, c. the TubiUideniaia, 
d. the Larieata, 

a. The group of the Mutiea contains the genera My 

caplinga and Cyelothurnt, the Ant-eaters of South America, 

The bodies of these animals are covered with hair, and they 

j are provided with very long tails, which are sometimes pre- 

I tensile. The skull ia greatly elongated, and the small pre- 




336 THE ANATOMY OP TEKTEBHATED ANOLiLS. 



1 



inasilte are bnt loosely connected with it. The jugal B 
ia incomplete. In Myrnieeqphaga, the pterygoids, wbidiiR 
rery long, atretch back to behind the level of the tjapflw 
bnllffl, with the whole inner edges of which they are nnilri 
either hj hone or by membrane ; and as, at the same tiiw. 
they unite in the middle line, the roof of tho palate ia greallj 
prolonged, and the posterior cares are bounded below M^ 
at the fiideH, by the pterygoid bonca. This arrangemaU 
is to be found in no other Mammala, except some CetaW 
nor in any other Tertebrata, except the Crocodiles. B* 
mandible ia vei"y alender, the ascending ramus, coronoidpTO 
ceas, and angle o£ the jaw, being obsolete. The ^linilir 
surface of the condyle ia flat. The hyoid is placed far hii 
beneath the posterior cervical vertebwe, and is connected wid 
the skull only by mueclee. The thyroid and the cricoid tai- 
tilagea are oaaified. The dorso-lumbar vertehrte are com- 
plicated by the presence of accessory articular proceesw 
Well-developed clavicles are present in the climbing Cycl* 
thwug didaetyluB, hat they are incomplete, or absent, in 
the other species. In the maaus, the outer digit, or digitt 
are devoid of claws, and the weight of the body, whas 
the animal walks, is supported upon its outer edge, wliidi 
is frequently thick and callous. Tho pes has five di^t*- 
each provided with a strong nail, and the sole rests upon 
the ground. 

The tongue ia extraordinarily long and protra^itile; 
not connected to the hyoid by the ordinary hyo-gUtam 
muBcles; but long muaclea. which are attached ti 
num {stemoglossi), retract it, while it is protracted by tbt 
genio-gloesi and etylo-hyoidei. 

Immense submaiillary glands extend back over the Uw 
rax, and cover the tongue with a viscid accretion, when it 
thrust into the nests of the ants, upon which the Mip-m*- 
copliaga preya. The insects, entangled by thousands IB 
this substitute for birdlime, arc then dragged back into the 
mouth of the Ant-eater, and awaUowed, The pyloric 
portion of the stomach ia ao exceedingly thick and t 
cular as to be comparable to a gizzai-d. The brain presents 



THE EDENTATA SQUAMATA. 337 

numerous convolutions, and has a large corpus callosum. 
The anterior commissure is also remarkably large. In the 
female, the uterus is simple, but has a double os uteri. 
The placenta is said to be discoidal in form in Myrme- 
cophaga diddctyla, 

b. The group of the Squcunuda contains the single genus 
Mania, species of which are found both in Africa and 
Southern Asia. In these singular animals, the body is 
covered with overlapping, homy scales, and they have the 
power of rolling up like hedgehogs. In walking, the long 
claws of the fore foot are bent under, so that their dorsal 
surfaces rest upon the ground, while the weight of the 
hinder part of the body is thrown upon the flat soles of the 
hind feet. 

The skull is elongated, the premaxilla is small, and the 
zygoma usually incomplete. The pterygoids are much 
elongated and extend backwards beyond the bullate tym- 
panic bones, but they do not unite in the middle line. The 
mandible has no ascending ramus, and its condyle is flat. 
Air passages in the walls of the skull place one tympanum 
in communication with the other and extend into the 
squamosal bone. There are no clavicles. The " xiphoid " 
extremity of the sternum is large, and may be produced 
into two long comua, as in Lizards. The mouth is toothless. 

The large salivary glands extend on to the thorax. The 
stomach is divided into a thin- walled cardiac sac, lined by a 
dense epithelium, and a thick muscular pyloric portion. It 
is always found to contain numerous stones. The placenta 
appears to be difluse and non-deciduate. 

c. The Tuhulidentata sure also represented only by a single 
genus, Orycteropris, which is a native of South Africa. The 
body is hairy, provided with thoracic and inguinal teats, 
and the ears are long, not short or rudimentary, as in the 
preceding genera. In both the fore and the hind limbs, 
the foot rests evenly upon the ground and mainly upon the 
plantar surfaces of the strong claws. The fore foot has 
only four digits, in consequence of the absence of the 
pollex, while the hind foot is pentadactyle. 



338 THE ANATOMY OP 

The skull has a complete zygtinia and weU-developod pn- 
masilto. The laohrymal bone ia large, and the laetrjiiii 
foramen ia situated upon the face. The tympimic kme v 
annular, and the jeriotic masa ao large, and enwra p 
much into the lateral walla of the skiill, as to remiDduw 
of ita proportions in the Sawopdda. The mandible bt 
an ascending' ramus. The clitvides are complete. 

The jawH are provided with teeth, the aubstanoe of wlud 
is traversed bj a great number of parallel vertical canili 
These teeth are rootleaa molara, and the greatest niuria 
which has been obaerred ia — , but the ainall anterior ona 
fall out, reducing them to ^. THe hindennoet, and lb 
email anterior onea, are aimple cjlinders, but the midJk 
teeth present a longitudinal graoye, on each side. 

The eubmasillary glanda are very large. The stomaii 
is divided into a right and a left portion ; the foniio 
having very thick and muacular walla, The intestini 
baa a ccecum. It is stated that the dudAis arteriotua long 

The two uteri open separately into the vagina. The pU- 
ceuta ia deciduate and diecoidal 

d. In the Loricata, the dorsal region of the body it 
covered by a carapace, compoaed of epidermal acalea, aid 
of auturally united quadrate, or polygonal, scutes, irhi^ 
are dermal oaaiflcationB, so that the whole atmctnra ii 
strictly comparable to the dorsal shield of a crocodile. That 
are the only mammals in which such scutea exiat. Whee 
fully develojied, the dorsal armour of one of theae animali 
preaentafivediatinct ahielda, the edgea of which permit of i 
ceri;ain amount of motion between them. One of tiiOt 
covers the head, and is called cephalic; another, nadtid. 
protects the back of the neck ,' a third, scapular, coren 
the ahoulders like a great cape ; a fourth, osually consietiiif: 
of a numbei' of free and movable segments, cover* tb* 
posterior dorsal and lumbar region, us the Ihorato^ 
dominal shield; and the fifth, the pelvic, is attached ^>I* 



THE EDENTATA LORICATA. 339 

deeper siirface to the ilia and ischia, and arches over the 
rump like a half dome. The tail may further be invested 
by a series of incomplete bony rings and scattered scales ; 
and scutes are distributed over the limbs. In one genus, 
Chlam/ydophortbs, the scutes are developed only in the pelvic 
region. 

In the skull the premaxillsB are well developed, and the 
zygoma is complete. The mandibular ramus usually has a 
weU-developed ascending portion and coronoid process. 
Clavicles are present. The fore and the hind feet rest 
upon the ground evenly, and indeed the hind limbs are 
usually plantigrade, or nearly so; but, in the singular 
genus Tolypeutes, the fore foot is supported upon the ex- 
tremities of the long nails. The pollex is always present 
in the fore foot, but the fifth digit sometimes becomes rudi- 
mentary. There are always five toes in the hind foot. 

In the genus JEvphractes, each premaxilla contains a 
single tooth, which, consequently, is an incisor. 

This group contains two divisions, the Dcusypodidce and 
the Glyptodontidoe ; both are South American, but the 
former is chiefly composed of living animals, while the 
latter only contains an extinct genus. 

The Dasypodidoe sure what are commonly known by the 
name of Armadillos, In this division the thoraco-abdominal 
shield, when present, as it is in all the genera except Chla- 
m/ydopJwms, consists of, at fewest, three, and, at most 
thirteen, transverse movable zones of scutes. 

In the skull, the ends of the nasal bones project beyond 
the level of the premaxillse, so that the nasal aperture looks 
more or less downwards. The premaxillae have a consider- 
able size, and articulate largely with the nasals. The 
anterior part of the jugal arch offers, at most, a rudimentary 
downward prolongation. The mandibular symphysis has 
but a moderate length, and the posterior alveoli of the 
mandibles do not extend along the inner face of the 
ascending poition of the ramus of the jaw. 

The teeth of the upper and lower jaws alternate, and 
hence their grinding surfaces wear down into ridges. 



340 THE ANATOMY OP VEETEBKATED ANIMALS. I 

The odontoid Tertebra ia aakjloseJ with a greater or 
Binaller number of its Bucceasors. The cervical vert«bn 
wbicb follow these have peculiar acccBsory articular em- 
faces; and the binder dorsal and the lumbar vertebra art 
also provided with aeceaBory articular facets and procefiB* 
A number of the anterior caudal vertebrse are al*sj» 
ankjloBed with one another, luid with tbe true BS^TaKin 
form the long sacrum ; and the trajiBTerBe processes vt 
Bome of these caudal vertebrm abut against th e inner ear 
faces of the iscbia. and become onkjlosed tberewith. 

The first rib is broad and flattened, and the anterior piect 
of the sternum ia eipanded. The succeeding vertebral riU 
are connected by ossified sternal ribs with the Bternnm. 
and these are articulated, not only with tbe Btemmn, but 
wibh one another. 

In the carpus, the cuneiform bone bends round the nnd- 
form, and articulates with the fifth metacarpal, when that 
bone ia present. The nngual phalanges of the manus are 
long and pointed. The femur Las a third trochajiter. ant! 
the four inner metatarsals are much longer than they are 

The division of the Glyptodontidm contains the single 
genua Glyptodon, which is essentially a large armadillo; 
but it departs, in some respects, not only from all thcae 
auimiils, but from all other Mammialia, and even stands 
alone among the Vertebrata. 

The carapace covers the whole body, but presents no 
movable thoraco- abdominal zones, inasmuch as it consista 
of polygonal plates firmly united together, and fringed bj 
a mai^^in of scutes with raised conical surfaces. 

The nasal bones are abort and brood, and their fwe 
ends do not project so far as the premarilte; whence tlie 
anterior nasal aperture looks slightly upwards as well a« 
forwards. Tbe premaiillEe, however, are veiy small boneft, 
and if they imite with the nasals at oil, do bo for averr 
short distance. The anterior portion of the jugal arch 
gives off a great downward process. The mandibular sym- 
physis is very long, and the posterior alveoli of the 





THE UNGULATA. 341 

Ible M-e situated upon the inner face of the very high per- 
jndicular part of the ramus. The teeth are trilobed, two 
Bep grooves excavating their kmer and their onter enr- 
And, as the crowna of those of eaoh jaw are placed 
(posite each other, thej are worn flat. 

y The last cerrical and the anterior dorsal vertehi-ffi are 

ankyloaedtogetherinto a single" tri-vertebral" bone, which 
movea by a hinge joint upon the third doraaL This and 
the succeeding dorso-Iumbar vei-tebne are immoTahly 
united, and, for the most pai-t, ankylosed, together. The 
head of the first rib is engaged in the Bocict furnished to 
it by the tri-vertehral bone in such a manner as to be 
immovable, and the rib is nut flat, but rounded and co- 
in the carpus, the cuneiform bone aitiGnlnites vrith the 
fourth, a9 weU as with the fifth metacarpal, the hitter hone 
being entirely supported by the cuneiform. The metacarpals 
and phaUngea are all very ahort and broad. The pollei ia 
rudimentary, while the fifth digit is fully developed. 

The Bupra-oondyloid ridge of the femur is nut distinct 
from the third trochanter, even if the latter caai be said to 
exist at alL The metatarsal hones are as bruad as they are 
long, or broader ; and. us in the fore foot, the majority o£ 
the phalanges are comparatively abort and truncated. 

The Nos-dkciduatb Mammalia. — I. Unhulata. — A 
large number of the non-deciduate Mammalia are con- 
veniently comprehended imder the title of the Ungulata, 
though it may be open to question whether the group 
thus named represents a single order, or more than one. 

In all the Uagulata the placenta ia either diffuse, that is 
to say, the villi are scattered evenly over the surface of the 
chorion J or it is cotryledonary, in which latter case, the villi 
are accumnlated in distinct patches on the chorion. Those 
patches are called colyledong. 

AH JJiiguiata have milk teeth, succeeded vertically by 
teeth of the permanent aet. The teeth consiat uf enamel, 
dentine and cement, and the grinders have broad crowns, 
with tuberculated, ridged, or folded e n a m eL 



I 



3i2 THE ANATOMY OP VEKTEBKATED 



ClayicleB are never present. The liiabs have not mo 
than four complete digits. The ungual pbahmgea & 
clothed in obtnae homy Bbeatha, whii;h are oommonly verj 
thick and go by the name of hoofs. Upon these the w 
of these quadrupeds ia UBnally supported, whence theyhma 
been called ungvligrade. Some few, however, rest the 
weight of tlio body upon the under surfaces of the phi- 
langes. or ai'e digitigrade. The metacai'pal and metatanai 
bones oi-e elongated, and take a vertical, or much iuctinri 

In the female, the mauuuEe are either few i 
when they are inguinal in position; or nnmerous, wheo 
they are disposed in two rows along the abdomen. 

The intestine ia very generally provided with a ctECUO 
of C 

The cerebral hemiapheres always exhibit convolutions, 
which are usually very numerous ; and, when the brain e 
viewed from above, the surface of the cerebellum is largely 
uncovered. 

The JJngvlata are diviaible into the PBriemdactyla and 
the Artwdactijla, though it is probable that the attejnpt to 
define these groups ■will break down with the increase of 
om- knowledge of foasil forma. 

1. In the Ferissodaetyla, the numbei- of the dorao-lnmbar 
vertebne is not fewer than twenty-two. The third digit 
of each foot is aymnietrical* in itaelf, and the toea of lie 
hind foot are odd in number (THg. 93, B). The femnr 
has a third trochanter (Fig. lOO-'l. The two facets upon 
the front face of the astragalus ai-e veiy unequal ; the les 
articulating with the cuboid bone. 

In the akull, the tympanic bone ia small; and, aa i 
sundry other mammal a, the root of the pterygoid process 
of the sphenoid is perforated by an aperture or canaL 

The posterior premolai- teeth are, generally, very like the 
molars. The stomach is simple, and the ccecum exceedingly 
liirge. 

The t«uta ai'c inguiuul, or aituatoit in the groin. Wboi 
It very nearly si 



PEEisaoDAc TVT.t , 

i head is piMvided with homy appendages, tliey a. 
irelj epideiinal and devoid of a bony core ; and they a 




tctarssl of the third digit. 2, 3. The metatu'salB of therud 

The Perisaodaclyla consist of the existing fiitnUies Eqitiil 
Oiiaooerotida, aoid Tapirid^e, and of the estinotPalaiotJwride 
md Maerauchanidis. 

1. The Eijmdx, or Sorsea aitd Aaeea, have one 



11 

a the 1 
:^arpal I 



344 THE AN4TOMT OF TfEETEBBATED ANIMALS. 

each foot — the third — miich longer and larger than 
rest. The latter are represented only by their metacarpal 
or metatarsal bones, the inner and outer toes being absent, 
or represented by mere ossicles (as niduaenta of their mebi- 
carpals or metatarsals) in all existing Equidie. Bat, in the 
extinct Hippctrwn, the second and fourth digits were com- 
plete, though small and lilce dew claws; while the mio- 
cene AnehUheriiMn, which m<^ nearlj approaches the 
FalmotheridcE, has the lateral toes much larger, and taking 
tieir sliare in supporting the weight of the body. 

Fig. g4.-A, Tigbt fore foot of a Hone. 1. R»liaB. 2. Groove In At 
front face of the radius. 3. ScaphBides. 4. Lunare. 5. Conet- 
fonUD. 6, Piaifoime. 7. MagouiD. 8. Uncifurme. 9. Metanar- 
pale, 111. 10. Al etacarpule, tv. 11. Sesamoid bones in the ligameDti 
at the baciiof the nietacarpo-phalttngBBl arliculation. 12. Proiinial 
phalaju (fetter bone). 13. Middle pbalani (coronHry). 15. Distal 
phalaoi (cufBn hone). U. Sesamoid bone in the tendon of the J(uor 
peiibraiu (called " navicular " by VeterinariaiiB). 

B, left hind foot of a Horse. 1. Tibia. 2. Calcaneum. 3. Astragalus. 
4. Cuboid. 5. NaviRular, or scaphoid. 6. EclnDuncifocm. 7. Me- 
tatarsale. Hi, 8. Metalarsaie, if. 9, 11, 12. Phalanges. 10, 14. Se- 
samoids. 

The dental formula is i. — c. r-77 P'"'' ^rj '" - jr;' The 
tooth here counted as the first premolar maybe amilktooti, 
as it appears to have neither predecessor nor euccessor, and 
soon disappears. 

The molar teeth present an outer wall, which is bicrescentic 
in transverse section; and two inner ridges, which aie 
curved more or leas inwai-ds and backwards, and coiTespond 
reapectively with the anterior and the posterior crescenta of 
the outer walL The valleys may be more or lees com- 
pletely filled up with cement, which also coats the tooth. 
The incisors are similar in form in each jaw, and in Equut 
and Si^arion their crowns present a wide and deep mediaJi 
cavity, formed by a fold of the enamel. 

These are the distinctive chai-acters of the EquidtB. It 
may be useful to add some special details respecting the 
anatomy of the Horae aa a familiar example of the perie- 
Bodactjle group. 



THE ANATOMY OP 

The Horse has aeven cervical vertebne, twentj-four 
dorait-lumbai- (eighteen or nineteen of which are dorsal), 
five aacial, and about eeventeen caudal vertebrffi. The 




irlebmof aHone. 1. The cudimentarjr (plat. 
2, 3. The pre- and paaUsygapophjsea. 5. The oonve» snteriarfMa 
□t' the conlrum. U. Its concave posterior face. 6, 7- The Um*- 
Tene proccssea ajid rudimeaUry ribs. 

atlaa ha^ very wide lateral proceaaes, the faces of which 
look obliqnclj downwards and forwards, and upwards ajid 
backwards. The centra of the other cervical vertebne are 
much elongated, strongly convex in front, and correspond- 
ingly concave behind. The neural spinea are obsolete in all 
but the aeventh. The Ugamenlum niu:k(e ia a great sheet of 
elastic tieaue, which eiteude from the spines of the anterior 
doi'aal vertebriB to the occiput, and is fised, below, into the 
neural arches of the cervical vertebne. 

In the dorsal region, the opisthocojlous character of the 
centra of the vertebne gradually diminishes, though the 
anterior face of the centmm of the last Iiiiubar is ttill dis- 
tinctly convei. The spines of these vertebne increase in 
length to the fourth or fifth. The spine of the sixteenth is 
vertical, those in front inclining backwards, and those be- 
hind a little forwards. 

In none of these vertebrEB do the prezygapophysea bend 
round the poBtzygapophyBes of the vertebra in front, as is 
often the case in the ArHodactijla. The transverse pro- 
cesses of the penultimate, and of the last, lumbar vertebne 
present concave facets upon their posterior margins, which 



348 THE ANATOMY OP 

articulate with convex facets developed upon the imtertn 
margins of the List lumbcir ajid first sacral vertebra le- 
spectively. 

Id the slinll, the ploiiie of the aupra-occipital is indined 
upwards and forwards, and gives rise to tie middle part 
of a transverse ridge which is continued at the sides into 
the aqoamosal. The ridges which Umlt the origins of the 
temporal muscles above, unite in the middle line poatfr 
riorty, and thus produce a low sagittal crest. The orbit is 
bounded behind by the united postorbital proceaaea of the 
frontal and the jugal. The lachrymal aperture lies in the 
orbit. The nasal bonea unite, for a short distance only, 
with the premaxilla. There is no prsnasal bone. The pos- 
terior margin of the palate is opposite the penultimate molar 
tooth. The glenoidal surface is tranavei-Belj elongated Bnd 
convex from before baokwarda. 

The tympanic bulla is not very large, and is ragoae 
inf eriorly. It is not anfcylosed with the Burrounding bones. 
The post-tympanic process of the squumosal does not 
approach the post^lenoidal process of the same bone, belcnr 
the nieaiua auditorioB. 

The proper mastoid process is distinct, but short. Thse 
is a long and strong paramastoid developed from th« esr 
occipital. 

The rami of the mandible are ankylosed at the Bymphjsia 
The perpendiisular part of each ra.mus is long, the condyle 
transverse and convesf rom before backwards, and the narrow 
coronoid process rises far above the level of the condyle. In 
a longitudinal section of the skuU the cerebral ehambur lies 
almost altogether in front of that for the cerebellum. 

The structure of the limbs of the Horse is such as 
might be expected from its pre-eminent cursorial powers. 

That exceasive development of the epidermis which gives 
rise to a nail takes place, in the Horse, not only upon the 
dorsal surface of the terminal joint of the digit, but upon 
its ventral surface and sides, and thus pi-oducea a hoo/. 

The animal is supported by these gi-eatly-developed nails, 
and hence is said to be ungvUgrade. The long axes oi its 



Aalonges are greatly inclined to the Hurfaee upon which U 

inds, while tiiose o£ the metacarpais and metntcirBald u 

Fig. 97. 




■Fig. 9".— Lungitudinal median gentinn of the foot of a Il&rae. 
■". The three phalanges. la. The nBvieulor Beaamoid. 
xor perforatas. B. The Heior pcrforiina. 19. Tho houf. 

perpendicular and greatly elonj^ted. The wriat of i 
Eerae thna cornea to occupy the middle of the length 
its fore-lej;, and eonatitutea whut ia improperly called t~ 
" knee." The heel is similarly raised to the middle of t 
liind leg, and is termed the " hock."' The forearm and tlii^ 
leg are free, hat their motiona are almost reatricted t 
antero-poaterior plane. The fore arm ia fiied in the prone 
position. The arm and thigh are closely apphed to the 
ddes of the body and inclosed in tho common integument, 
aa to he capable of very little proper motion. At t 
le time, the asia of the humenis is inclined ohliquel 
backwards and downwai'da, at right angles with the long as 




350 THE ANATOMY ( 

of the scapula ; and that of tbe femur obliquely forwards 
and dowiiwfti*dH at right angles with that of the os imnomi- 
naium ; and the long usee of both these bonoB make a great 
angle with those of the fore-arm and leg respectiTely. Bach 
limb thus forms a sort of double C ^pi*iBg< upon the top of 
which the weight of the body is supported — in the hind 
limbs by means of the aolid connection of the ilia with ths 
sacmni; in the fore limbs, by the great muscular alings 
formed by the scrraUig magnus smd the levator angvXl tcOputo. 
Fig. &8. The scapula is long and 

w i the low spine has n" 
; the coracoid process 
is small, and there is no clavicle. 
The head of the bumenis 
looks backwards, and the distal 
articular surface of tbe bone 
is completely ginglymoid. He 
two bones of the antibrachimn 
are ankyloaed ; the shaft of 
the tilna becomes exceedinglj 
slender, and its small distal en<I 
is distinguishable onlywith diffi- 
culty. The articular mirfaoe for 
the carpal bones is, tberefore, 
almost wholly f nmiahed by the 
radius. There are seven carpol 
bonea, the trapezium being ob- 
solete. A lino prolonging the 
axis of the third metacarpal 
and that of the o» m,agnwm does 
not pasa through that of the 
hinare, but correapondB more 
■BO, nearly with the jnnctioa be- 
"li' "^f ""'"''' t^ppn ^'^''J'^'iMfcs and iMnore. 
i. Ma^Tm! The poUex and the fifth digit 
7. Trapcioides. are suppressed, or represented 

onljbymin«te nodules of bone, and the only complete digit 
is the third; the second and the foui-th being represented ' 




Pl^. 98.— Front view of the ' 



THE HOBSE. 

only bj tte aplintlike metacarpal bones. The third meta- 
csarpal. whitb is somewhat flattened from before backwards, 
learly symmetrical in itself. Carefnl observatioa, how- 
erer, shows the inner moiety to be ratber the broader. 

Tbere are two large sesamoid bones (the greater sesainoids) 
developed in tbe ligaments which connect the metacarpal 
'with the basal pbalajiz; and one transversely elongated 
seaasmoid gives attachment to the tendon o{ tbe perfoi'ating 
flexor, and Ilea upon, the ventral aspect of tbe joint between 
the middle and the distal phalanx. 

The ossa innominaia are elongated, and their long axes, 
on the length of which depends the proportional size of the 
" qnarter " of a Horse, form an acnte angle with the spine. 
The creata of the ilia lue wide and directed transversely, J 
and the aympbyais pubis is very long. 
Fig. 9B. 




I Fig. go.— The usa innominiila of a Horse viewed from the teft e!de 
and behind. 1. The crest of the Ilium. 2. The eurfafle b3> wbicli it 
articulates nilb the saorum. 4. The scetabulam. 6. Tbe iauhium. 

The femur has a large third trochanter (°, Fig. 100), into 
which tbe ijlutcens mtudmue is inserted. Its bead presents a 



THE AN4TOMT or VEKTEBRiTED 



deep pit for the round ligament, and there is a, peculia. 
verj eliaracterifltio foaaa ('") on the inner and posterior 
face of the diatal moietj of the bona. 



Fig. 100. 



The proximal end of tbe fibula 
IB reduced to a mere rudiment ; iti 
shaft ia not represented bjr bdne; 
aai its diatal end is ankfloeed 
with the tibiit, and has the Ap- 
pearance of being ao external 
malleolar process of that Ixsie. 
The distal end of tbe tibia pre- 
senta two deep, obliquely-direct«d 
concavities, which correspond 
with the convexities of tlie astia- 
galua. 

There are six or seven tarsal 
bones, according as the ento- md 
meso-cnneiform bones remain dis- 
tinct or liecome ankyloaed. The 
aetmgalus (Fig. 93 A, 94 B) is ex- 
tremely clmi-acterietic. It presents 
two convex ridges separated by a 
deep fossa, and directed obliquely 
from behind and within, forwards 
and ontwarda, to the tibia, ; and it 
has a nearly flat distal facei 
not borne upon any distinct neck, 
which articulates almoat wboUv 
with the naviculare, presenting 
only a very email facet to the 
cuboid. 

The naviculare and the eoto- 

- of cuneiform are peculiarly broad and 

w. flattened in form (Fig. 93A,9*B). 

^. The metatarsne and digite repeat 

4 \,eaer tro- the ai-rungtments of the tore limb ; 

,. . '" ^,'n "p™ hut the principal metatarsal in 

ligameut. 10. Fossa. , j ■ -^ _^ 

• I. Coucijlaa. more slender m ita proportions. 




or THE HORSE. 353 J 

I Vnd is flattened fi-ora side to aide rather tlin.n from before I 

I'backwarda (Fig. 93 B, 94,B). I 

Aa might be expected, the prineipuJ peculiarities of the I 

acular Bjatem of the Horse are to he observed in the I 

The eerratug ntagnva and the levator aiiyitli acapvliE (wlucli I 

L really form one muscle), together with a demo-scapulcms, I 

n the great sling already mentioned, by which the weight I 

L of the font part of the body is transmitted to the anterior I 

estremitiea. The power of abduction is hardly needed by I 
a pnreiy cnrsorial animal ; hence the deltoid is reduced 
to its scapular portion, which is very small. On the other 
hand, the pro- and re-tractora, the flexors and extensors, are 

well developed. The supra, and infro-spinudw are large. J 

There is a great cephalo-hvmeraKi, answering to the elavi- I 

cular portions of the human stemomastoid and of the 1 

deltoid, which run into one another, in consequence of the 1 

L total absenue of the clavicle. The anterior portion of the 1 

KBternomastuid is fixed to the mandible, and thus becomea. I 

F " stemoniasillaiy." I 

The latitamms dorei and lerea muscles are rery large, as J 

are the flexors and extensors of the antibrachiiim. I 

The sapinutors and pronators are wanting ; but there ts J 

a distinct enAensor miniini digiti, the tendon of which unites ] 
with that of the eixtenDor convmwnis. Radial and ulnar 
extensors of the carpus are also present. 'The Jkm>r per- 
foratum has only a single tendon, which splits, and is attached, 

as usual, to the sides of the middle phalanx. The Jleror per- . 

K forana also haa only a single tendon, which pierces the d 

i iormer, and is insei-ted into the leaser sesamoid and th* 1 

distal phalanx. I 

The intsTosBei of the third digit are represented only Igr J 

the ligaments which connect the greater sasamoid hones I 

with the metacarpal, and in which a few muscular fibres are 1 

eometimea found. There are said to be two others, one for 1 

Leach lateral metacarpal, and a Itimbricalia. i 

K In the hind limb, the femoral muscles are tn the HoraO; I 
Ktlte same as in Man, but eoonnoualy developed. ThereiM 



35i THE ANATOMY OF VEBTEBEATED 

no tibialU anticaa.perotumti loTigus, or hrevk, nor any tibialis 

poeUeus. 

The eicteTisor lowgus diffitorvm has a head whicli aiises 

from the eitemnl condyle of the femur ; there ia a airaple 

extetieor brevig. 

The flexor haUucis and flexor digitorumpeifoTans unite into 

the single perforating flexor tendon for the diatal phalanx; 

while the perforated tendon ia the termination of that of 

the plaTitaria, which passea over a pulley furnished by tie 

calcaneum. 

The deciduous or milk dentition of the Sorae has the 
following formula : d.i. — d.c. ^ d.m. — , It is com- 
plete at birth, with the exception of the outer incisors, which 
appearbeforothefoalia nine months old. The incisors hare 
the same structure as in the adult. The canines and first deci- 
duous molars ai'e simple and very small, the canines being 
smaller than the molara. In the upper jaw, the other 
deciduous molars ail have the same Btnictnre. The onter 
wall of the tooth is bent in such a manner as to present, 
from before backwards, two concave Burfacea separated by » 
veitical ridge. From the anterior end, and from the middle, 
of this out*!r wall, two laminte of the crown pass inwards 
and backwards, so as to be convex inwards and concare 
outwards, and tbiis to include two spaces between, them- 
selves and the outer wall. From the inner surface of the 
binder part of each of these crescentic laminse a vertical 
pillar is developed, and the inner anrface of the pillar is 
grooved vertically. The outer wall, the laminee, and th« 
piUarH are all foiined of dentine and enamel, thickly coatod 
with cement. The attrition which takes place during mas- 
tication wears down, the free aurfacea of all these parts, bo 
aa, in the long mn, to lay bare a anrface of dentine in the 
middle of each, aun-oundedby abandof enamel, and, oataide 
this, by the cement with which the interspaces are filled- 
The band of enamel is simple luid unplaited. The general 
pattern of the worn surface maybe described as consisting, 
externally, of two longitudinal crescents, one behind Ute 



I'BX TEETH or THE HOBSE. 

otter, and with their concavities tumed outwardB, whieli 
arise from the wear of the wall ; iutenial to these, of two 
other crescents, partly tninsverae in direction, and con- 
nected by their anterior ends with the waD, which ariae 
from the wear of the laminie ; &nd attached to the inner 
surface of these, two hour-glaas- shaped surfaces, produced 
by the wear of the gi-ooved pillaj^. 

In the mandible, the structure of the molars and the 
resulting pattern are quite different. The outer wall pre- 
sents two convex mirfacea separated by & longitudinal 
depression, and thus reverses the conditions observable in 
the npper molars. The result o£ the wear of this is, ne- 
cessarily, two crescents, the concavities of which are tumed 
inwards. A vertical pillar, longitudinally grooved on ita 
inner face, is developed on the inner face of the tooth at 
the junction of the anterior and posterior crescents, and 
gives rise to a deeply bifurcated surface when worn, A 
second smaller pillar appears in connection with the inner 
face of the posterior end of the outer wall. 

Thua the grinding surface of the upper molars may be 
represented by four crescents with two inner pillars; and 
that of the lower molars by two crescents with two 
pillars. The upper crescents are concave outwards 
lower concave inwards; and by this anrangement, together, 
with the unequal wear of the dentine, enamel, and 
a permanently uneven triturating surface is secured. 

As is the general mle among Mammals, the first 
manent molar is the first permanent tooth which app< 
(unless the eruption of the inner incisor be contemporary-' 
with it), and it comes into place and use long before 
deciduous molars are shed and replaced by the premolars. 
Hence, when the last premolar comea into place as a freali 
and im.wom tooth, the first molar, which lies neit to it, 
already considerably worn. This disparity of wear if 
tained for a long time, and furnishes a very useful 
of distinguishing the last premolar from the first molai- in 
the adult, when, as in the Horse, the premolars and molars 
are very 




356 THE i-NATOMT OP VBETEBKATED ANIMALS. 

The firet deciduouH molar uauallj falls out when the 
first pi-e molar appears, and ia not replaced; but it iaocca- 
eionaU J retained. All the other milk teeth have sucoeasors, 
and there are three permanent molars. Consequently the 
dental formula of the adult Horse ie 

i. ^ c.j^ pni. ^* m. ^ = W- 

The permanent canines are the last teeth to be fullj 
developed, and, in the mare, thej often do not malce theii 
appearance. The upper eaninea are distant from the onter 
iaeisors. while the lower eaninea are quite dose to them. 
In both jaws there is a wide inteiTal, or diiutema, betweoi 
the eaninea and the premolare. 

The deep valley of the inciBor teeth becomes iilled np 
with masticated matter, and thus the dark " mark " ia pio- 
duced. As the incisora wear down, the mark changed its 
form in consequence of the differences in the transrene 
section of the vulloy at different points; and eventually, 
when the wear has extended beyond the bottom of die 
valley, it disappears. The presence or absence of thp 
" mark " thus aervea as an indication of age. The ata-uctuM 
and patterns of the gi-inding siirfocea of the perman^t 
molars ai's essentially the sameaa those of the milk molars; 
but the enamel becomes more or less plaited : and, at an 
advanced period of life, the development of the long teelh 
is completed by the formation of roota. It ia important to 
notice that the last molor of the Hoi-ac is not moi-e complex in 
its sti-ucture than the other molars, and that the last milk 
molar ia not more complex than the premolar which anc- 
ceeds it. 

The alimentary canal of the Horse is about eigbt times 
as long aa the body. The stomach, simple iu its form. 
presents a cardiac and a pyloric division, which are sharply 
distinguished by the dense epithelium which linea the inner 
surface of the former. 

The ctBcum ia enormous, having fully twice the viJnme 
of the stomach. There is no gall-bladder. A cartilage 
ia developed iu the septom o£ the heart. Thcra is JU' 



THE VISCERA OF THB HOBSE. 3S7 | 

Eiiataeliian valve, and only one anterior cava remainH. Tha 1 
aorta divides immediately after its origin into an anterior | 
and a posterior trunk; the latter becomes the tboracio 
aorta; the former is the source of tie arteries for the 
head and the anterior extremities, giving off first the left 
subclavian, and then as on "inaominata" supplying the right 
eubclavian and the corotidB. 

The trachea divides into only two bronchi, n 
broncliua being given off to the right Inng, In the brain 1 1 
the following points are worthy of notice. The meduUaJ 
oblongata presents corpora trapeiaridea. The flocculi do:l 
not pi-oject at tbe sides of the cerebellum, and the vernuB-I 
and lobes of the cerebellum are onsymmetrically coc 
Inted. The cerebral hemispheres nre elongated and s 
cylindrical, and do not overlap the cerebellum when the 
brain ia viewed from above. The eulci are very deep, and 
aeparttte numerous gyri, upon tbe upper and outer surfaces 
of the hemispheres. The uncinate gyrus (or natiform pro- 
tuberance) and the region which answers to the insula, are 
not bidden by the overlapping of the convolutions ia the 
lateral aspect of tbe brain. The sylvian fissure is indi- 
cated. The corpus callosum ia lai-ge. and the anterior ci 
miasure is of moderate size. The posterior comu of thaj 
lateral ventricle is wanting. 

Large air sacs are connected with the Eustachian tubes. 

The teates pasa into a scrotum, but tbe inguinal canal I 
remains permanently open. 

The prostate is single. Oowper's glands are present, and J 
there ia a large uiertu moaeiiUnue. The large penia ig I 
ahelterud vrithin a pi'epuce and ia retracted by a special J 
muscle, which ariaea from the sacrum. 

The uterus is divided into two comua, and the vagina of 
tbe virgin mare is provided with a hymen. Tbe period 
of gestation is eleven months. The yelk sac of tbe fretus 
ia small and oval. The allantois spreads over the whole 
interior of tbe chorion and covei-s the anmion, which L 
vascular. The minute villi which it supplies -with v 
iue evenly scattered over the whole surface of tbe cborion,J 



The eristing Equidce ai 
Asia, and Africa ; and a 
which have homy patches o 
Umba — atove the wrist h 
eide of the metatarsuB i 



' VEBTBBBATED A 

i-e naturally restricted to Enrope, 
re diBtingniahed into the Horses, 
n the inner sides of both pairs of 
1 the fore hmh and on the inner 
1 the hind limh; and the Asaes, 
which poBnesa euch callosities only on tlie fore limha. 

Fossil remaina of Equidce are abnndiint in the later ter- 
tiary deposits of Europe, Asia, and the Americas ; but the 
group is not known to be represented earlier than the 

The Bquidte axu among the very few groupa of Mam- 
malia, the geological history of which is sufficiently well 
known, to prove that the esisting forma have resulted from 
the gradual modification of very different ancestral types. 
The skeleton of the older pliocene and newer miocene 
Mifparion very closely resembles that of an Ass, or a mo- 
derate-sized Horse. There is a curious depression on the 
face in front of the orbit, somewhat like that which lodges 
the " larmier " of a stag (traces of which are observable in 
some of the older species of Eqwua); otherwise the craniam 
is alt<^ether like that of a Horse. Again, the shaft of the 
ulna is very slender, but it is larger than in the Horse, and 
is distinctly traceable throughout its whole length although 
firmly ankylosed with the radius. The distal end of the 
fibula is so completely ankylosed with the tibia, that, as in 
the Horse, it is difficult to discern any trace of the pri- 
mitive separation of the bones. But, as has been already 
mentioned, cauh limb possesses three complete toea — one 
strong, mediaii, and provided with a laj-ge hoof, while the 
two lateral toos are so small that they do not extend beyond 
the fetlock joLut. In the fore limb, rudiments of the firat 
and fifth toes have been found. 

The teeth are exceedingly like those of the Horse, but the 
crowns of the molars are shorter; and, in the upper jaw, 
that which, in the true Horses, is a large fold of the inner 
face of the tooth becomes a detached pillar. The smaller 
plications of the enamel are also more numerous, close-set, 
and complicated. On the outer face of the lower milk 



^ 



mulara there is a column Buch as exists in the Stags, 
this a I'udiment exists, aa a fold, in the corresponding teetli 
of the existing Horse. 

In the genus AnchUheriuim., all the known remains of 
I which are of older miocene {and, perhaps, newer eocene) 
' age, the skeleton in general is atiil extraordinarilj like 
that of a Horae. The skull, however, ia amaller in pro- 
portion than in the Horae, and the jawa are more slendei". 
The hindennoat molar tooth ia situated farther back under 
the orbit, and the orbit itself ia not completely encircled by 
bone, as it is in the Horses and Hipparions. 

The sh^t of the ulna is stouter than ia Hippt 
and is less closely united with the radius. The fibi 
appeara, at any rate in some caaea, to have been a. compl 
though slender bone, the diatul end of which ia atill close^ 
united with the tibia, though much more distinct than in 
the Hipparions and the Horses. In some specimens, how- 
ever, the middle of the shaft seems to have been incom- 
pletely oaaified. Not only are there three toea in each foot, 
as in Hipparion, but the inner and the outer toes are ao 

t large that they must have rested upon the ground. Thus, ,^J 
BO far as the limbs are concerned, the Attehdtheriwn is jnst^^^l 
Buch a step beyond the Mipparion, as the Si^arion i^^^^H 
beyond the Horae, in the direction of a less specialized ^^^H 
quadruped. The teeth are atill more divergent from the ^n 
Equine type. The inciaora are amaller in proportion , and 
their crowns lack the peculiar pit which chura/^terizea thoae 
of -Egwwg and Hippwrion. The first grinder is proportion- ^1 
ately much larger, especially in the upper jaw, and like the ^^H 
I other sis haa a abort crown and no thick coat of cement. ^^^| 
I The pattern of their crowns is wonderfully simplified. ^^H 
I The fore and hind ridges run with but a slight obh'quity ^ 
I across the crown, and the pillars are little more than en- 
I largements of the ridgea, while in the lower jaw these 
"Hal's have almost diaappeared. But the foreu 
[ principal grinders is still somewhat larger 
3t, and the poaterior lobe of the last lower raola 
in the other Eguidie. 



360 THE ANATOMT OT VEKTEBBATED ASIMAia. 

In all those reapeuts in which Anehitherium departs from 
the modem Equine type, it approacheB that of the eitinct 
PalcEotheria ; and this is so much the case that Cuvier 
considered the i-emains of the AnchitheriuTn. with which he 
was acqURJuted to be those of a. species of PahBotherium. 

b. In the RhitiocerotidfB the second, third, and fonrtli 
toes are nearly equally developed in both the fore and the 
hind feet. 

The dental formida is )'. fr; ^^ i. — c. — p.m. — m. jj 
But the teeth differ from those of the Horae in many 
othei' respectis besides the number of the incisors and the 
absence of canines. Thus, the npper ineisora differ greatly 
in form from those which are situated in the lower jaw; 
and, in Bome species, incisors aj« absent. Their crowns are 
not folded as in the Horae. The peculiarities of the 
grinding teeth will be mentioned below. 

The skin is very thick and may be converted into a 
jointed armour; the hair is scanty, The upper lip is 
much produced and is very flexible. In some species one. 
or sometimes two, homa are attached in the middle line to 
the nasal or frontal bones. But these horns are formed, as 
it were, by agglomeration of a gi-eat number of hair-like 
shafts. 

The distal phalanges of the ti-idactjle feet of the Rhi- 
noceros are invested by small hoofs; bnt these do not 
entirely support the weight of the body, which rests, in 
great measure, upon a large callous pad developed from the 
under face of the metacarpal and metatarsal regions ; theae 
are much shorter than in the Horse. 

The dorsolumbar vertebrffi arc twenty-two or twenty-three, 
of which twen^ are dorsal. There are four sacral and 
twenty-two caudal. The oervicul vertehrffi, as in the Horw. 
are strongly opisthoccelous, and the transverse processes 
of the last lumbar articulate with those of the penultimate 
lumbar and witli the sacrum. 

The skull differs from that of the Horse in the absence 
of any frontal or zygomatic processes, in consequence 



wence 

ice of J 



which the orbit and temporal foBaa form one cavity. The 
nasals are immense, and ure separated fi-om the premaxilhe 
by a wide extent of the maxilla, on each side. The pre- 
maxilltB ai'e relatively small, and reduced to little i 
than their palatine poiiions. The glenoidal Buif ace of the I 
mandible is transverse and conves. The squamoaal sends 
down an immense post- glenoidal process, which ia longer 
than either the post-tympanic or the paramastoid. It imitca 
with the post-tympanic to form a. kind of false auditory 
meatus, in the absence of any proper ossified canal of that 
kind. The periotic and the tympanic bones are ankylosedf ■ 
the tympanic being a mere irregular hoop of bone. Th«. I 
para magloidea is completely hidden by the junction of the 
short post-tympanic with the long paramastoid. The hinder 
margin of the bony palate is opposite the middle of the 
antepenultimate molar. 

The mandibular condyle is tranarerse and convex. The 
perpendicular portion of the ramus is large, and the coro- . 
noid process ascends slightly above the condyle, 
vertical and longitudinal section of the skuU, the fonu trf 1 
tie cerebri cavity ia Been to be aimiiar to that of ths 1 
Horse. The inner and outer tables of the bony roof of the I 
skull are separated by great air-cavitiea. 

The spine of the scapula has no acromion, but gives I 
off a strong recurved process from the middle of its 1 
length. 

The radius and ulna are complete, but are ankylosed. 

The carpus has the eight ordinary bones. In the manus 1 
the digits ii. iii. iv. are complete, and a bony tubercle 1 
articulated with the outer facet of the euneifonae repre- \ 
senta digit v. The digit iii. ts largest and longest, and ita 1 
phalanges are symmetrical in themaelves; those o 
digits ii. and iv. are not symmetrical in themselves. The 
terminal phalanges have somewhat the form of the coffin J 
bone of the Horse. 

The ilia have wide transversely directed crests, t 
Horse. The femur is pi'ovided with a veiy strong third 
trochanter- The tibia and the fibula are complete, and 



361 ^fl 



362 THE ANATOMY OP TEKTEBBATED ANIMALS. 

tb.e taraiia has the ordinary seven bones. The pulley of tbe 
aatragalua is not very deeply grooved, and is hardly at all 
oblique. The facet for the cuhoid is very Bmall. The 
metatarsala reeemhle the metacarpals in their niuaber and 
symmetry, but there is no rudiment of the fifth. 

In Bome species of Rhinoceros there are .j.- inciaorB in the 
milk dentition, and jr^ or — incisors in the permanent 

dentition. In the latter the upper incisors are la^e, 
long-crowned teeth, rery unlike the lower ones, of which 
it seems probable that only one pair, in any case, are 
permanent teeth. In some Bhinoceruaea, as has been 
already stated, the adult is devoid of inciaor teeth. 

Thare are no caniuea in either dentition. Of the 
four milk molars, the first, as in the Horse, is smaller than 
the others, and ia not replaced. The atmcture of both the 
upper and the lower molars ia anbatantially the aame as in 
the Horse, but the roota are developed much sooner; 
the laminse of the npper molars take a much more trans- 
verae direction; the lamina of the upper molars do not 
develop pillars, though acceasory create may be developed 
from the two faeea of the poaterior lamina ; the lower 
molara have no piUara ; and the cement does not fill up 
the valleys between the wall and the laminie. 

The cardiac division of the simple, though large, etomaoh 
is lined by a white calloua epithelium, as in the Horse. The 
small intestine presents large processes or tags, li.^lf an inch 
long or more, upon which the true villi are home. The 
ctecum is very large, and the colon enormous. There is no 
gall-hladder. The heart and brain are very similar to 
thoae of the Horse. 

The male can hardly he eaid to have a scrotum, as the 
testes lie close to the ahdomiual ring. A prostate, vesiculoi 
seminolea, and Gowper's glanda are present. The long penia 
has a muebroom- shaped glans, and the animal is retro- 
niingent. The coraua uteri are proportionately longer than 
The teats ai-e two and inguinal in poBitioi 



THE TAPIBID^. 

The characters of the fcetal membranea and the nature | 
of the placcntation are unknowii. 

At the present day the genua Rhinoceroe ia confined to 
Africa and Asia. The African apeciea all have two horns, 
& nearly smooth akin, and the adult has no incisors. The 
Asiatic species have one horn only (except that of Snniatra, 
has two). The skin is marked out by deep folds into 
ehields. and the adults have well-developed inciaore. 

Bhinoceroses are known in the fossil state as far back 
as the miocene epoch, if. tichorhinm. with the na^al 
septum ossified, and a covering of long woolly hair, i 
habited Europe and Asia during the cold of the glacial .1 
epoch. B. mcieivus had four digits in the manua, ancL 1 
larger incisor t««th than any exiatiug species. R. fieato- f 
protodon bad more numerous incisora than any othra* J 
Hpeciea. 

!. In the Tapiridt thei-e are four toes on the fi'ont foot, 1 
though the ulnar digit docs not reach the ground. Thfi J 
hind foot has three toea. 

The dental formula ia i. j-75 c. j— p.m,. —^ m. T-75. 

The molar teeth each present two transverse, or slightly J 
oblique, ridges, connected by a low wall eatemally. 

The skin is soft and hairy, and the muzzle and snout are J 
prolonged into a short proboscis. 

The Tapirs have twenty-three or twenty-four dorsolumba* J 
vertebrte. of which nineteen, or twenty, are usually dora^> F 
The centra of these vertebraa, and the transverse processes irf>l 
the last lumbara, have the same pecnliarities as those of thO'.l 
Horae and Rhinoceros. There are seven Hacral and about' | 
twelve caudal vertebre. The skull is partly Rhinocerotic, ' 
partly Equine in its characters. Thus there is a sagittal 
crest — the post-tympanic processes are large, but they are 
not so long as the paramaatoids, and they do not unit« with 
the post-glenoiilal procesaes beneath the meatua. In these 
respects the Tapir is Horae-like, but in the following it iB 
more Rhinocerotic. 

Thus the tympanic ia quite rudimentary j tl 



364 THE ASATOMY OP VEBTEBEATED i 



d prooeaa is larger than in the Horse; the orbit is 
not separated from the temporal fosaa; the nasals are 
widely separated from the premaxilke; the premasilliB are 
very email, and are early ankyloeed. 

The hinder margin ot the oaaeoua palate ia opposite the 
anterior edge of the penultimate molar. The nmndibular 
rami unite in a very long symphyaia ; the ascending portion 
of the ramus is large, and projects backwards with a eonvei 
edge in a remarkable manner. There ia a high coronoid 
process. 

In the fore limb, the scapula has no acromion, and tlie 
coracoid is a mere tubercle. The supraspinous fosss is 
very mnch larger than in the Horse or Rhinoceros, lia 
radius and the nlna are complete, bnt not movable npon 
one another. Although, by the completion of the fifth digit, 
in addition to the second, third, and fourth, there are four 
digits in the manus, the Periasodactyle character is mani- 
fested by the fact that the third is longest, and symmetrical 
in itseK, while the others are asymmetrical The femnr has 
a strong third trochanter ; the fibula ia complete ; the aa- 
tragalus more Erfainocerotic than Equine. Thei-e is no 
trace of a hallui. but the fifth digit of the pes appears to 
be represented bj an osseous rudiment. 

In the presence of the full complement of inciaora and 
canines the Tapir is more Horse-like than Ehinocerotie. 
but ia still very pecuh'ar ; for the outer upper i 
larger than the canines, while the outer lower it 
much smaller than the canines, and are apt to fall out »t s 
certain age. The canines, are still more closely approxi- 
mated to the incisors than in the Hoi'se, especially itt the 
lower jaw, and, consequently, the diastema ia very lai^. 
The six posterior m.o!ars in the upper jaw, and the five 
posterior molars in the lower, present nearly the same 
structure. There ia a low outer wall with two slightly 
marked concaritiea (in the maxillary teeth) or convexitien 
(in the mandibular teeth) on its outer face. From this two 
ridge- like laminee run inwards and a little backwards across 
the crown of the tooth. The valleys are broad and shallow. 



THE PAL^OTHEEIDJE. 



and tlie coat of oeraent very thin. The molai' tooth of 
Tapir thuH repreaenta the plan of structure commoi 
the Periisodaelyla in its simpleet form. Deepen the valleya, 
increase the curvature of the wall and laminw, give the 
latter a more directly backward alope; cause them to de- 
velop accCBBory ridges and pillara, and increase the qnantitj 
of cement ; and the upper molar of the Tapir will graduall] 
pass through the structure of that of the Rbiuoceros 
that of the Horse. 

In the anterior upper premolar (or laili: molar P) the 

anterior moiety of the crown is incompletely dereloped. 

In the anterior lower premolar the anterior basal process, 

which exists in oil the molars, is excessively developed, ao that 

the crown of the tooth assumes the hicrescentio pattern (#1 

the Rhinoceros' lower grinder. This probably indice 

the manner in which the Tapiroid form of inferior 

is converted into the Rhinocerotie, or Equine, form. 

. The Btomach is simple and oval, the cardiac and pyli 

I orifices being closely approximated. The ctscum is pro. 

' portionally smaller than in the Horse or Rhinoceros. There 

ia no gall-bladder. The heart is devoid of a septal bone 

and of a Eustachian valve. There is only a siTigle vena 

eava aiiterior, and the aorta divides into an anterior and a 

posterior trunk. There is no third bronchns. No diatinct 

' acrotnm is present. There are veaioute seminalea and 

K prostatic glands, but no Cowper's glands. The placentation 

I is diffuse. The teats are two, and inguinal. 

There are two or three species of Tapir at present living 
in South America and one in South-west China, Malacca, 
I luid Sumatra. The genus Tapimg has been found fossil in 
I Europe in rocks of miocene age. The closely allied estinct 
r genera Lophiod-oa (and Coryphodon V) carry the TapiridtE 
[ back through the eocene epoch. 

d. The FahcotKeridm. — These are all eitinct animals, the 
which are found in the older tertiary rocks ; 
which are closely allied, on the one hand, with the 
es and, on the other, with the Tapirs, 
e type of thefamilji Falaaoihuriam, roBemhleathe Tupir 






itity I 

s *)^^H 

ped. ' 

that ; 

em(#^^H 



366 THE ANATOMY OF VEBTBBEATED A 

in moat respecte, but has only three digits in the manna as 
well ai in the pea. The dental formula, howevei', is 
*■ vi *■ i^ -P'™' n "*' al' '^^ diastema is amaller than in 
the Tapir, and the pattema of the grinding teeth of both 
jawa are more like those of the Rhinoceros. 

e. The Maorauehenida, — The genus Maerauchenia \a also 
an eitinct form, which occurs in later tertiarj or quater- 
nary deposits in South America. 

The feet are tridactjle, and the dental formula a 
^' s^i"' i^iP''"^' 4^™" 3^' ^^^ teeth are diapoaed in a nearly 
continuous aeries. The crowns of the incisors present a 
deep fossa, as in the Eqaidas. The molavs ai'e in part 
Equine, in part Bhinocorotic in character. The bItuII ia, on 
the whole, Equine, but the nasal bones are Tery short and 
tapiroid. The vertebra} of the long neck are extraor- 
dinarily similar to those of the CmneliAa!, and especially of 
the Llamas. * 

2. The Artiodactyla. — The number of the dorso-liunbar 
vertebriB in this group is always fewer than twenty-two, 
and rarely exceeds nineteen. 

The third digit of each foot ia asymmetrical ia itself, 
and usually forma a aymmetrical pair with the fourth 
digit; and the functional toea of the hind foot are even in 
number — that is to say, either two or four. 

The femw is devoid of any third trochanter ; the facets 
upon the distal face of the aati-alagua are subequal, that 
for the cuboid being nearly as large as that for the navicular 
bone. The tympanic is large, and the pterygoid pi-ocees 
of the sphenoid is not perforated. 

The posterior premolar teeth usually differ a good deal 
from the succeeding molars, being simpler in pattern. The 
last milk molar in the lower jaw is trilobed ; but thia is also 
the ease in some PeriasoAaetyla. 

The stomach is more or less complex. The ciecum, thongh 
well developed, is smaller than in the Ferig^odactyla. 

The mamnuB are inguinal ov abdominal. When lioma are 



THE SUID^. 367 

present, they are double, supported, wholly or partly, by 
the frontal bone and provided with an osseous core, which 
la almost always an outgrowth from that bone. 

The Artiodactyla are divisible into the Non-Bwnwiumiia and::] 
the Ruviinantia. 

A. The Won-SiwniiKtjiiia usually have more than o; 
of incisors in the upper jaw. The molar teeth have either uM 
ma,ininilla,te, atransveraelj ridged, or arhinoccrotic pattern.^ 
In only one genus, Dicolytea, are any of the metatarsal or ■ 
metatai'sal bones ankyloaod together. They are devoid of 
homa, and the stomach has rarely more than two divisiouB. 

The Non-Euminantia are divisible into three familiea ; — 
The Swidce, the Hippopotamidie, and the Anophiheridie ; but 
more or fewer of the members of this last group may havQ 
ruminated. 

a. The Suidas have the slrin of moderate thickneas and I 
hairy,- the limbs slender, and the third and foui'tli toe»| 
oonaiderably longer than the second and fifth. The teatfl. J 
are abdominal, and there is a scrotum. The dental formula' I 
vaa'iea couBiderubly, but the molars have a, multituberculatftV 
or transversely ridged Ending surface. 

In the genus Sms, the dental formula is i. '— c. — - 



By way of contrast with the Horse, I add some mi 
detailed statements regarding the anatomy of the Fig as a 
common and very good example of an Artiodactyle. The 
Pig has seven cervical vertebne, nineteen* dorsolumbar, of 
which fourteen are dorsal, four sacral, and twenty to twenty- 
three caudal. The atlas has wide oblique alie, as in the 
Horse. The centra of the other cervical vertebra; are short, 
with nearly flat articular surfaces, and this flatness ia 
retained in the dorsolumbar region. The cervical and 
dorsal vertebns are provided with long spines, that of the 
first dorsal vertebra being the longest of all. Up to the 
I twelfth dorsal the spines all slope backwards ; beyond it tl 
Idope forwai'ds, if at all. 

* £xccptioDaUy, the number m^ ba iausucd to twenty-two. 




368 THE iKATOMY OP VEBTEBRATED ANIMALS. ^^| 

In the ninth doreal vertebra the poatzjga.pophjaie pre- 
senta on ui-ticuliir surface on its dorsal side, and the pre- 
zjgapophysis of the tenth vertebra benda round ao as to 
overlap tliis surface. This character ia continued in the 
succeeding vertebne aa far as the first aaci'al. The trans- 
verse procesaea of the penultimate and last lumbar vertebiB 
are tolerably long, but they are inclined forvf arde aa well m 
outwards, and do not articulate with one another, or with 
the first sacral. 

In the skull the supraoccipital is inclined upwards and 
forwards into a great transverae creat, to which the parietale 
contribute but little. The parietala are early ankjlosed. 
The temporal ridgea remain widely aeparated in the middle 
of the roof of the skull. 

The frontal bono has a post-orbital proceaa, and so has 
the jugal, but the two do not meet so as to bound the orlnt. 
The lachrymal is very large, and its two canals open on the 
face. The naaals are very long, and the premaxilte unite 
with liem for a great distance. There ia a pnenaaal booe, 
or oasification of the eartilaginoua septum of the nose. The 
bony palate extends back beyond the level of the last molar. 
The base of the external pterygoid process ia not perforated. 
The surface for the aiticulation of the lower jaw is trans- 
versely elongated, convex from before backwards, and 
bounded behind and internally, by a post -glenoid al ridge. 

The tympanic buUa is very large, and the exceedin^j' 
long bony meatus curves upwards and outwards, between 
the squamosal and the mastoid, with both of whick it is 
ankjlosed, to the root of the zygoma, where its aperture 
looka almost directly upwards. The post-tympanio is 
closely appressed to the poat-glenoidal process, so as, with 
the latter,to encircle the meatus. The proper mastoid ia 
distinct, though short, but tkere is a very long paramastnid 
developed from the exoccipital and extending behind and 
below the mastoid. 

The i-ami of the mandible are completely ankylosed at 
the aymphysis. There is a long perpendicular portion of 
the ramus. The condyle ia tranavereely elongated and 



conves, antero-poateriorly ; the coronoid proceas ascends 
hardly higher than it. In a longitudinal section, the 
cavity of the MTiibral hemiBpheres is more rounded than in 
the Hoi-se, and liea above, aa weU. as in f rout of, that tof. 
, the cerebellnm. 

The scapula ia long and narrow. It is devoid of acromioiji, J 
and has hut a small coracoid prucesa. 

The radiuH and "1"" are complete, bub are antyloaed to. -I 
gether in the prone position. The diatal end of the ulna ] 
articulateB with the cuneifoiin bone. 

The carpus containB eight bones, but the radial bone in .1 
the distal Beiuea may be either the trapezium, or a. rudimenfc 1 
of the poller. The lunare, aJid the axia of tie third meta- 1 
carpal have the aame relation aa in the Horse. The third J 
and foiU'th digits are larger than the other two, aoid form. 4 
a symmetrical pair. There are sesajnoid hones c 
Ventral face of the articulations between the metacarpal and ' 
the basal phalanx, aud of that between the middle and tho 
distal phahingea. Each distal phalanx ia incased in a, small 
hoof. The f emin- has a round ligament. There ia no third 
trochanter. The £bala is complete, and its distal end 
articnlates with the calcanenm. There are the nanal acven 
tarsal bones. The tibial end of the astragalus has the form 
of a, deeply-grooved pulley, the direction of the groove 
corresponding nearly with the length of the foot. Thai 
distal end presents a convex suboylindrical surface divide 
by a ridge into two facets, of which one is somewhat les 
than the other, and articulates with the cubo 

The metatarsus and phalanges of the pes are disposed like J 
the corresponding bones in the manus. 

The fore part of the body is supported upon the anti^rior J 

I extremities by a muscular sling composed of the eerratut, 1 

'or an^li scapulw, and steraosca^larls, much as in the 

ae, with which the Pig exhibits a general correspondcnoe 

a myology. The muscles which move the digits, how- 

:, have undergone leas modification. Riu"h digit of the 

}, for example, has its proper extensors, and there is 

eTieor ossia melacoTyi ^oUicis viiuuh ends on the basal 



370 THE ASATOMT OP VEBTEBEATED ANIMAia. 

phalanx of the second digit. Aproiuitm' teres is i 
into the lower half of the radius, Tha flacor perforat/tis'has 
only two tendone, which go to the third and fourth digits. 
The flexor perforana sends two large tendons to the third 
and fourth, and two small ones to the second and fifth 
digits. There is a large intei-osgeus muscle on the radial 
aide of the third digit, and another on the ulnar side of the 
fourth ; hut the inteToaaei of the intei-spa^e betnreen these 
iligitB are represented only by fibrous tiasue. The s 
•.lad fifth digits have each two interotsei. There is no 
gofaw. The strong and fleahy plantarU ai'iaea from tie 
outer oondyle, beneath the gaetroiynemnu i oud, iuclos«d 
between the two heads of the latter, passes to the i 
side of the tendo Achillia: its tendon curves round this 
tendon, passes over the end of the calcaneum as ovei 
pulley, enters the eole, and finally divides into the t 
perforated tendons of the third and fourth digits. The 
inner and outer digits of the i>es, like those of the njanm 
have no perforated tendons. 

A large and fleuhy flexor hoRacia longaa arises from the 
fibula and the interosseous ligament, and its broad tendon 
passes iuto the sole and coalesces with the tendon of tl 
smaller flexor longiis digiiorrtm. The conjoined tendoDs 
divide into four sKpa— two large, median, and two e 
inner and outer. These go to the distal phalanges and 
Boaamoids of the respective digits. 

The tibicdis posticus is absent, but tliere is a small tibialii 
anUmis. 

A very complicated muscle represents the exteiiaor longvs 
digUarum and fkeperoiUEUe tertiiia. It arises hy(a) a Htrong 
round tendon from the outer condyle of the femur, just in 
front of the external lateral ligament. From this tendoD 
proceed two fleshy bellies, one of which supplies tendons U 
the third, fourth, and fifth digits, while the other ends in a 
broad band of tendinous fibres, which is ineei-ted into the 
third metatarsal and the ectoeuneiform. Into this band is 
inserted 1,6) the second fleshy head which arises from the 
Upper port of the tibia ; and it is traversed by the tendon 



THE DENTITION OP THE PIG. 371 

of (c) the tliird head, which is slender, arises from the 
fibula, and sends its long and delicate tendon to the 
dorsum of the second digit. 

The peronoeus longus is present, and its tendon is inserted 
into the entocuneiform and the second metatarsal. There 
is no peronceus hrevia. Aperonceu8 4ti et 6ti digiti arises from 
the upper part of the fibula, behind the peronceus longus, 
and ends in a tendon which passes behind, and on the inner 
side of, that of the latter muscle, to the dorsum of the foot, 
where it divides into two branches which join the extensor 
sheaths of the fourth and fifth digits. 

The extensor brevis goes to the two middle digits, and is 
connected with the middle tendon of the extensor longus. 

The interossei are similar to those of the manus. 



The formula of the milk dentition of the Pig (which is 

3-3 , 1—1 

3^ '^■<'- i=r 



.3*3 1—1 

complete at the third month after birth) is d.i. — d.c. — - 



d.m. -—' 

The outer upper incisors are directed obliquely outwards 
and backwai'ds. In the upper jaw, the anterior two molars 
present sharp longitudinal edges, while the posterior two 
have broad crowns with two transverse ridges. In the 
mandible the anterior three molars have sharp longitudinal 
edges, while the hindeimost has a broad, three-ridged crown. 

The first permanent molar is the first tooth of the per- 
manent set which comes into place (at about six months 
after birth), and the pennanent dentition is completed in the 
thii'd year, at which time the first deciduous molar, which 
is not replaced, falls out. Hence the foimula of the per- 

3*3 1 1 3*3 3'3 

manent dentition is i. -— c. -— p.m. -— m. — r = 40. 

3*3 1 — 1 -^ 3*3 3*3 

The permanent incisors in the upper jaw have short, 
broad, vertically-disposed crowns, and lie in a longitudinal 
series, the external being separated by an interval from 
the others. The elongated inferior incisors lie side by side, 
are gi-eatly inclined forwards and upwards, and are grooved 
upon their upper or inner faces. The strong, angulated 



372 THE ANATOMY OF VERTEBttATED ANIMALS. 



crowns of the dminea are bent upwards and outwai-ds in 
Iwth jaws. Tbej work ugninBt one anotlier. ic sul-Ii a, 
manner, that the upper wears on its anterior and eiterual 
face, the lower on the posteiior aspect of ita apex. Tlie 
crowiiB of the premolars are all brunght to a cuttiiig longi- 
tndinal odgo, while the molars have broad ctowhb witi 
trunBverBe ridgea subdivided into tubei'cles. Of these ridges 
there are two in the anterior two molars of each jaw, whils 
the posterior molar is more complei, having at fewest three 
distinct ridges. The inolar teeth all develop rootej but the 
canines continue to grow for bo long a, time, in the Boar, 
that they might be said to be rootless. 

The alimentary canal ia ten or twelve times as long M 
the body. 

The stomach is less simple in atructnre than it appears 
to be at first sight. The cardiac end prBsente a snull 
MEcum, in which ie a, apii'al fold of the mucous membrane; 
and, at the entrance of the cesophagns, the epithelial lining 
is folded so as to form a sort of valve. Folds of the mncona 
membrane, between which there lies a groove, extend frwo 
the cardia towards the pjlorus, &nd foreshadow the mora 
developed stmctiu'e obseiTable in Ruminants. 

The ciBCiim has not above one-sisth the capaci^ of the 
stomach, and the ilium projects into it, bo as to form & 
very efficient iliocsecal valve. The liver ia provided with a 
gall-bladder. The heart ia devoid of an EustacUia.n valve, 
and sometimes, but not always, poaaesaes a aeptal ossifi- 
cation. 

There is only one anterior cava. The aorta givea off an 
tnnomMwto, from whence the right aaholaviim and the two 
carotide arise, and a left subclavian. This ia an arrange- 
ment midway between that observed in the Horse and that 

The trachea, before it dirides, gives off a third bronchus, 
which passes to the right lung ; and the lungs are deeply 
lobed. 

In the brain the cerebral beiaispheres rise abcrve the cere- 
bellum much more than they do in the Horse. 




HE BTJiDa;, 373^ 

s contained in a long prepuce, a 
is devoid of a bone and provided i 
F with, retractor muscles. The prostate ie lobed, There is a 
I large uteraa maacnlinns and well-developed vesicolte be 
I nales. The ducts of Oowper's glands open into a cceoaL \ 
cavity contained in the muBcnlar bulb. The testes descend 
into a scrotnm. In the Sow, a pair of Gaertner's cowafs, c 
perainten.t Wolffian ducts, open into die vestibule beside 
the uiinai'j meatus. The uterine cornua are very long, and 
the ovaries are lobulated. The period of gestation is sixteen 
to twenty weeks. The ovum, at first sphtrieal, retains that 
form until it attains a diameter of nearly liaJf an inch. 
It then rapidly elongates into a coiled filiform body, as much 
as twenty inches long. Botli the ailantois and the nm^ 
l>Uical vesicle at the some time assume a. apindle-ahape. I 

The ailantois soon becomes divided into an internal epi- i 
thelial and an external vaacular layer ; the latter becoming 
united with the chorion, througii the eitrcmitiea of whioh 
the ailantois eventually passea. The villi are very nu- 
merous, minute, and apread over the whole am-faco of the 

I The Suidai exhibit great vaiiations in their dentition andJ 

I in the structui'e of the stomach. B 

In Forats {the Babyrusaa) the dental formula is i, _B 

e. — p.ia.m. — ; the canines are enormously elongated aitdfl 

recurved, and the pharynx is provided with pecuhar ei^| 

I The stoniach is divided into three chambera, and th^| 
groove leading from the (Esophagus towards the pylorus &B 
I more distinctly marted than in Bits. ^ 

I In Dicotyhs (the Peccaries) the upper incisors are also 
I reduced to two on each side, and the molar teeth present 
L transverae ridges, which are more diatinct and less tuber- 
LvDolated than iu Sim. - 

B The stomaeh is divided into three sacs, and is provided^ 
B'vith an (Bsopliageal groove as in the preceding genas. ■ 

ft The middle metatuBala and metiu^fptvLi coalesce into :^| 



374 THE ASATOMY OF VEETEBKATED ANIMALS- 

cannon bone, and the fiftL digit of the pea is represented 
only by its metatareal. 

In Fhaeoehmrm (the Wart-hog) the npper incisors are re- 
duced to one pnir, and the hindermost molars, which are 
the only ones whieh are not shed in the old animal, are of 
great size, and poeaesB a complicated, tnberculated, Htmc- 

Tlio SiiidcE are represented by one genns or another in 
all the great distributional provinces except the Anstraliaii* 
and Kovo-Zelanian. Poixus is peculiar to part of the 
Malay Archipelago, Dicoiylea to Soutli America, and Pha- 
cochsrtiB to South Africa. 

A great variety of Swine-like Ungvlata esieted during th* 
depoaition of the older tertiary strata, and are the earliest 
known members of the gi'oup, 

6. The Hippapotaniidce. are represented at present onlj 
by the genera Hippopotamiis and Chceropua. These uniwiala 
have a huge head, a heavy body, covered with a. thidi in- 
tegument, provided with scanty haii-a, and short, etont, 
tetradactyle limbs, all the four toes of which rest on the 
ground. The female has inguinal teat«, and the mal«U 
devoid of a scrotum. 

TLe dental formula of the adidt Sippopotamiu is <■ j:; 
e. — p.m. — m. —. while C/uprqptis has only twp incison 
in the lower jaw. The tubercles of the molar teetli, when 
ground down by mastication, present a double trefoil 
pattern, and the hindermost inferior molar is trilobed. 
The incisors are straight and tusk-Uke. The very large 
and curved canines are directed downwards in Oie upper 
jaw, upwards in the lower. Their mutual attrition wean 
the njiterior face of the extremity of the upper, and tha 
postCTior face of that of the lower, flat. 

The milk dentition consist of d.i. — d.e. ~ d.m. — , The 
last lower deciduous molar ia trilobed, and the first deciduona 
jiiolar persists a long time, and seems not to be replaced. 
* The Pftpuan pig may tiie^ieBiiuAtQiiioei. tuna "iK-s* 



THE 



H The atouwch is dmded into three or f oiir compai'tmeiitB, ] 
H.and there is no ccEcum. The liviir has a gall-bludder, and 
■ 'the kidnejH are lohnlated. 
H The skeleton ia very pig-like, but in Bome respeetB ap- 
I proachea the RuminantB. The centra are aUghtlj eonTex 
1^ in front, and concave behind, in the cervical regitin, hut not I 
elaewhere. Tiie prezygapophyses overlap the postzygapo- ] 
physes ia the poBterior doraoIumhaT vetehrffi. On the other 1 
hand, the tranaYi^ree proceaaes of the last Inmbar vertebrtft J 
articulate with thoae of the preceding and Huceeeding ver-.j 
tebrffl, as in the Horse and other Pevissodactyles 

In the skuil the orbits are nearly complet* posteriorly, J 
and they become almost tnhnlar by the outward pi-oduction I 

I of the frontal and lachrymal bones. 
The nasals and preinaxiUso unite for a great extent. Th«' j 
osaeona palate ia long ; the large tjTnpanio bone : 
ankyloaed with the approximated post-glenoidal aud post- ■] 
tympanic proceHses. 
The mandible is estremely massive, and has a backwardly ] 
produced angle. 

The scapula has a, short acromion. The radius and ulna 
are complete and ankylosed, and there are eight honea in 
the carpus. The fibula ia complete, and the tareua, which 
a bones, much resembles that of the Pig. 
The Sipp^^otamidrE are at preaent confined to Africa y 

Pint a apecies abounded in the rivers of Europe in the lata 
tertiary times. 

Merycopolamus of the miocene Fauna of the Sewalik " 
Hills appears to have been a Hippopotamid, with upper 
molars having a quadri-ci-escentic, ruminant-Uke, pattern, 
and lower molars bi-orescentic and rhinocerotic in character. 
In the Siiidm and RippopoiamidiK, it is interesting to 
remark the timdency to tiie coalescence of the metacai-pals 
and metataraala in Dicofjiflg,- the disappearance of the upper 
■s by pairs in Dicotyles, Porciis, and Phacocliae 
.e great complexity of the stomach in Dicotyles 

.3 they are bo many approximations towards tl 
rnotnre of the Kflininant drtiodocbijUji- iiiii'iia'^ 



hi 

■ in 

ft. 





376 THE A5AT0MY OP yEBTEBBA.TED ANIHAI.S. 

Bition from the non-Eiiminant tn die Raminajit groiipa, 
or ratlier the common stem of both, is fumiahed by the 
Anoploth eridcE. 

e. The family of the ArtoplotheridfB exclusively contains 
extinct MaiuintUa belonging to the eocene and miocene 
epodba. They are most eonspicuoualy distingniahed by the 
circnmstance that the teeth, of which there are eleren on 
each aide, above and below, in the adult dentition, are njot 
intermpted by any gap in front of and behind the canine, 
as they arc in the preceding genera, bnt form an uninter- 
mpted and even series, as in Mnn 

The dental formnla of the adult Atuiplotheriitm is 
'■ 3^ ''^ T^ P''"^- t^ ™' 3^' Hupposing that the first pre- 
molar is really sach, and not a persistent milk molar. 

The upper and lower molars have the general structure 
of those of the Bhinoceros; but the lamina of the upper 
are bent more backwards into parallelism with the outer 
wall, and a strong conical pillar is developed on the inner 
side of the anterior lamina. The skull resemblea that of 
the Ruminant TraguUdiB in structure, but the orbit is in- 
complete behind. The rest of the skeleton partly resembles 
that of the Pigs, and partly that of the B,uminaats.* 

hxXiphodon and CainoWteriMm, which are ordinarily com- 
prised among the Anoplolheridts (though, in all probability, 
they are true Ruminants of the Traguline group), the orUt 
is complete, and both upper and lower molars put on the 
Ruminant oharacteristics. In dentition, CainotheriuTn differs 
from a Ruminant only in possessing all the upper incisors, 
while no existing adult Ruminant has more than the outer 
upper incisors. We are of course unacquainted with the 
structui'e of the stomach in those animals, bat they bo 
closely resemble Ruminant Artiodactyla that it is highly 
probable they may have possessed the faculty of rumination 
in a more or less perfect degree, 

* In Ano/ihlluriHm lecaidarmm the digit ii. it dBveloped In nob 
foot, though not nearly bo loug as Hi,, wliioh is nearly ayin metrical in 
Itself. There is an appronoh to the Bame struoture lu the manna of 
Cainothtrium. 



(. Tlie SwmiTumtia. — In the commonly recognised n 
B ot this division of the Artiodadyla thi^re ie n 




378 THE ANATOMY OF VEETEBKATED 

more tlian one pair of inoiaorB, and tliat the outermost, ii 
the upper jaw of the adult. Caninea may or may not eriat 
in the upper jaw; they are always present ia the lower 
jaw, and are generally inclined forwards and closely 
approximated to the incisors, which they nsuallj resemble 
in forw. It conaequently happens tliat they are often 
reckoned as incisors, and Buminanta arc said to pOBseas 
eight cutting teeth in the lower jaw. 

With one esceptiou (Syeemosehiis), the metaearpal a 
tataraal bones of the third and fourth digits early become 
tinkylosed together into a single, so-called, cannon bant. 
There is a peculiar bone called maUeola/r, which takes Uie 
place of the distal end of the fibula, articulating' bdo* 
with the calcaneum. and above with the astragalus 

The great majority of the Ruminiuitia possess boma, the 
bony supports, or cores, of which are developed on each 
side of the middle Une; and, except in the Giraffe, on 
outgrowths of the frontal bones. 

The stomach has, at fewest, three diviBiona ; and. in thi 
majority of the Eiwminantia, it has four compartments. 

If the stomaeh of a typical B,nminant, such aa a Bheep o) 
an Oi, he examined, it will be found to be divisible into two 
principal moieties, the one cardiac and the other pyloric, 
while each of these is again subdivided into two others. 
Thus the extreme cardiac end of the cajdiao moiety i 
dilated into an enormous sac of irregular form, the mncoDa 
membrane of which is raised up into a vast number of cltwe- 
set papillfE. This chamber is the ifinnen, or Pavnth. It 
commimicates, by a wide aperture, with a much smaller 
chamber, which constitutes the second sub-division of the 
cardiac moiety. This is called the Betieulwn, or Honsyeomb 
Btomach. from the fact that its mucous membrane is raised 
up into a great number of folds, which cross one another 
at right angles, and, in this way, inclose a multitude of 
hexagonal-sided cells. The reticulum communicates by a 
narrow aperture with the first subdivision of the pyloric 
moiety, which is somewhat more elongated in form. The 
mucouB membrane oi tlua aiibii-naVoii ii 




, Uflophajua; Jtn,, rumen: Rel., reticulnm ; /*»., paaUerium 
■■ ' ; JV'. pjloras. 

— mpletely aoroBS the cavity of the cliamber; tliey thus 
lediiee that cavity to a aeriea of narrow radiating c\v£ta 
taterpoHed between tlie lamelliE. When this portion of the 
Btomach is alit open, longitudinally, the lamelliB fall apart J 
like the leaves of a book, whence it has received the f ancif «1 J 
le of the Fsalterimniioai. aiiatoTOia\jB,-w\iiifc\i^^uiB!«*^!tf 



380 THE ANATOMY OP VEBTEBEATED ASIMALS. ' 

it that of Manyplies. The fourth segment of tbe etomacli, 
or second enbdiviaion of the pyloric moiety, is termed tie 
Ahomaswm,, or Bennet stomach. This portion is compcira- 
tively Blender and elongated, and its mucous membrane haa 
a totally different character from that of the other three 
segments, being soft, highly vascular, and glandular, and 
raised into only a, few longitudinal ridges. 

It will be observed that the psalterinm is ao constructed 
aa to play the part of a very efficient strainer between the 
reticulum and the abomaauni; nothing but Tery finely 
divided, or semi-fluid matter, being capable of traveraing 
the interstices of its lamelhe. 

The gastric apei-tiu« of the <ssophagus is situated at the 
junction of the paunch and the reticulum; the margins o( 
its opening are raised into muscular folds, and are pro- 
duced, parallel with one another, along the roof of tbe 
reticulum to the opening which leads into the psalterinm. 
When the lips of this groove are approximated together, 
a canal is fonned, which conducts directly from the ceso- 
phagus to the paaltorium. 

A Ruminant, when feeding, cropa the grass rapidly and 
greedily, seizing it with its tongue and biting off the bundle 
of blades thua eoUeoted, by pressing the lower incJaorB 
against the callous pad formed by the gnm which covers 
the pre-maxillte. The bunches of grass are then hastily 
swallowed, accompanied by abundant saliva. After grazing 
nntil its appetite is satisfied, the Ruminant hes down, usually 
inclining the body to one side, and remains qniescent for s, 
certain apace of time. A sudden movement of the flanks is 
then observed, very similar to that which might be produced 
by a hiccough ; and careful watching of the long neck will 
show that something is, at the same time, quickly forced up 
the gnllet into the cavity of the mouth. This ia a bolus of 
graas, which has been sodden in the fluids contained in the sto- 
mach, and is returned, saturated with them, \o be masticated. 
In an ordinary Ruminant this opei-ation of mastication is 
always performed in the same way. The lower jaw makes a 
first stroke, aay in the direction from left to right, while the 



THE ACT OF KUMINATION. 



^necond stroke, and all those which follow it unUl the bolna ! 

^Rb auffieieatiy maHficated, takes place from right to left, iw 
in the opposite direation to that of the first. While the 
mastication is going on, Ereah qnantitieB of saliva are 
poured into the mouth, and when the gi'aas ia thoroughly 
ground up, the semiiinid prudnot is passed back into the 
phaiynx and swallowed once more. These actions orej 
repea,ted until the greater portion of the grass whiclt.l 
iiaa he«n cropped ia pulpified. I 

The precise nature of the operation, the external featuregS 
of which have now been described, has been the subject odm 
much investigation and diacuaaion. The following pointafl 
appear to have been clearly established ; ■ 

1. Rumination is altogether prevented by pai-alysis ofl 
the abdominal muadee, and it is a good deal impeded by ] 
amy interference with the free action of the diaphragm. J 

2. Neither the paunch, nor the reticulum, ever becomeftj 
completely emptied by the process of regurgitation. ThaB 

ijtaunch is found half full of aodden fodder, eveu iu anional^^ 
^which have perished by starvation. ■ 

3. When solid aubatancea are swallowed, they paea iadif-H 

■ Eerently into the rumen, or reticulum, and are conatantl^B 
(Iriven Imckwarda and forwards, from the one into the otlier^fl 
^iy peristaltic actions of the walls of the stomach. ■ 

4. Fluids may paas either into the paunch and the re-l 
Scidum; or into the paalterium, and thence at once intal 
(he fourth stomach, according to circumstances. I 

5. Rumination is perfectly well effected after the lipttl 
af the cesophageal groove have been closely united by wire ■ 
Ifntures. I 

It would ttppear, therefore, that the cropped grass pasaea \ 

into the reticulum and rumen, and ia macerated in them. 

But there is no reason to believe that the reticulum tukea 

any special share in modelling the boluses which have to be 

returned into the mouth. More probably, a sudden and aimul- 

Ltaneous contraction of the diaphragm and of the abdominal J 

RKmscles, compresses the oontentsof the rumen and reticulum^ 

Buid di-ives the sodden foddei against the cardiac apertoredfl 



m 



382 THE ANATOMY OP VERTEBEATED ANlMALa. 

the stomach. Thia opens, and then the cardiac enrt of the 
CEsophagua, becoming paasively diliLted, receives aa mnch of 
the fodder aa it will contaia. The cardiac apei-ture now 
becoming closed, the bolaa, thus aliut off, is propelled, by 
the reversed peristaltic action of the muscular Tvaila of the 
(Esophagns, into the niouth,-wbereit undergoes the thorough 
mastication which has been deacribed. 

The sodden fodder is prevented from passing oat of Ihe 
pealterial aperture of the reticulum, in part by the narrow- 
neea of that aperture, and in part by the fine gratiiig 
formed by the edges of the pealterial laminie. But when 
the semifluid matter, returned after maatication, once more 
reaches the cardia. it is compelled to pass towards the psal- 
terial end of the reticulum (even apart from the guidance 
afforded by the lips of the CBsophageal groove) on acoonnt 
of the dii'ection of the fflsopbi^us and the bounding of 
the cardiac aperture, on the side of the mmen. by a raised 
ridge. The chewed matter thus flowing over the surface 
of the more solid contents of the reticulum reaches th« 
psalterium; and, in consequence of the fine state of 
division of its solids, readily traverses the interspaces of 
the lameUffl of that organ, and passes into the fourth 
stomach, there to be eubmitted to the action of the 
gasti-ie juice and to undergo the digestion of the protein 
compounds, which have remained imaffected by the previous 
mastication and insalivation. 

The Jiu/minantia are divided into three groups : a. the 
TragtdidfE, b. the CotylopJiora, and e. the CamelidcE. 

a. The TragulidcE are a remarkable family, fonneriy 
united with the genus Moeckus, and still commonly known 
under the name oi Musk Deer, though they are devoid 
of the musk sac and, in other respecls, are totally different 
from Mosckue. They are at present restricted to southern 
Asia and Africa; and they are particularly interesting, 
as affording, in many respects, a connecting liuk i)etween 
the typical Ruminants andtheother^i'iiodae/^ia, especially 
the AnoplotheridiB. Thus, tlio second and fifth digits ore 
complete in both fore and bind feet, and the mebicaipals 



THE TRAGULID-a:. 383 

and metatarsals of the third and fourth digits unite veiy 
late, or, as in one genus, Hyoemoschiis, not at all. The 
canines are well developed in both jaws, and the premolar 
teeth are sharp and cutting. 

The oesophagus opens at the junction of the rumen with 
the reticulum, the communication between the two being 
very wide (Fig. 102 B). The epithelium of the rumen is papil- 
late, and there are two oesophageal folds, as in ordinary- 
Ruminants, but the psalterium is represented, only by a very 
short and narrow tube, the lining membrane of which is 
devoid of folds. 

The surface of the hemispheres of the brain has fewer 
convolutions than in any other Ruminants, though this may 
very possibly be connected with the small size of the 
animal; as it is a general rule that, within the same group, 
the brain is less convoluted in small than in large animals. 

The blood corpuscles, small in all Buminantia, are 
remarkably minute in the TragulidcBy not exceeding ^q^q-q 
of an inch in diameter. They have circular contours. 

The placenta is very nearly diffuse,the foetal villi being scat- 
tered over the chorion in bands, not collected into cotyledons. 

As further remarkable peculiarities of this group may 
be mentioned the ankylosis of the malleolar bone with the 
tibia, and the tendency to ossification in the pelvic liga- 
ments and of the aponeurosis of the muscles of the back, 
in adult males. Finally, the navicular, cuboid, and ecto- 
cuneif orm bones in the tarsus are all ankylosed together. 
If, as is probable, Xiphodon is one of the Tragulidce, the 
group has existed since the eocene epoch. 

b. The Cotylophora are, like the preceding group, unguH- 
grade, but the outer metacarpals aud metatarsals are in- 
complete at their proximal ends, and the middle ones are 
early ankylosed into a cannon bone. The malleolar bone is 
always distinct. The navicular and the cuboid bones of 
the tarsus are ankylosed together, but rarely with any other 
tarsal bone. The premaxilla is devoid of teeth in the adult. 
The stomach has the structure which has been described as 
typical. 



384 THE ANATOMY OF 

The blood ccirpuflclea are circular, and may have a 
diameter of ae little as -gjj^ of an inch. 

The f(Etal villi are gathered together into bunchea o 
cotyledons, which may present either a. convex or a concar 
face towards the uterus. They are received into persistent 
elevations of the mucous menihi-ane of the utems, the sur- 
faces of which present a reverse curvatoi-e. 

All the CotyU>phora except Moielms, the true Miisk Deer, 
are provided with home, but these horns ai-e uf two kjnds. 
The bony core, in the one case, is ensheatbed in a strong 
homy epidermic case; whUe, in the other, the epidemuB of 
the integument which covers the core does not become ao 
modilied. In the former kind of horn, the core becomes 
excavated by the extension into it of the frontal sinueea. 
whence the ruminants which possess such boms are not n&- 
frequently called Caoicomm t Antelopes, Sheep, Goats, Osenj. 
As a general rule, the horny sheath persistH throughout 
life, growing with the growth of the core. But i 
renoarkable Prong-homed Antelope of North Americn 
{Ani-iloeapra), the homj sheath is annually abed and replaced 
by a newly-formed one. 

Of the second kind of bom, or tLat which acqnirea no 
homy sheath, there are also two kinds. In the Girafie, 
tbe horn cores aa'e attached over the coronal suture, at the 
junction of the frontal and parietal bones, with which they 
are not ankylosed; tbey persist thronghout life, and are 
always covered by a soft and bairy integument. 

In the Deer, on tbe other band, the frontal bones grow 
out into solid processes, which are, at first, covered by 
soft and bairy integiunent; generally they ai'e developed 
in tbe male sex only, but both sexes have them in the Bein- 
deer. The boms attain their full size very rapidly, and 
then a circular ridge, which makes its appearance at a 
short distance from the root of the horn and is called 
the "hwr," divides the bom into tbe "pedkel" on tbe 
skull side of the burr, and the " betim " on the opposite side. 
The circulation in the vessela of the bemn now gradoBlly 
languisheSj its integnment dies and peels off, and the dead 



■bony Hubatanee beneati ia eipoaed. Ahaorption and J 
doughiiig neirt ocaur at tlie extremity of the pedicel, jnat ' 
M might happen in any other case of necroHis. The beain 
and hiuT are shed, and the end of the pedicel scabbing 
over, freah integument gradually grows up under the scab, 
eventually restores to the eitremity of the pedicel its 
.■jristine smooth and hairy covering. 

The rapidity with which the development of bony mattef'J 
Snto Deer horn takea pla«e is wonderful, horns weighin 
172 lbs, having been produced in ten weeks. 

The Cotylophora are represented in all parts of t 
■except the Australian and Novo-Zelanian provincea. Tiqf I 
3 not yet been traced back further than the miocane I 
epoch. 

■. The CameiuJce or (Tyhpoda) ai'e devoid of horns; and, 1 
unlike the other B>uminauta, they walk upon the pahnsx I 
and plantaj surfaces of the phalanges of the third and'l 
fourth toes, which are alone developed. Broad integn*J 
mentary cushions form a sole to the foot ; while 
are flattened and can hardly be called hoofa. 

^Tbe arches of the cervical vertebrce, and not their tt-aiw>1 
Terse processes, are perforated by the canal of the vertebral|J 
Krtery; a character which the caniela share with the | 
JfocrawcftewMte. 

The metacarpals are separated by a, deep cleft, and th« 
disfcd phalanges of the digits are nearly symmetrical in 
themselves. The distal facets of the astragalus are more 
unequal than in the other Btiminantia, and the navicular 
L and cuboid bones are not ankjlosed together. 
H The premaxiUie have a single strong outer ii 
V each side. Large curved and pointed canines are deveJope^.l 
in eath jaw, and are quite diatinct front the series of the"| 
incisors in the mandible. There are not more than Atb 1 
gi-inding teeth in a contiuiioua aeries above and below. 

The stomaoh is unlike that of the typical Rumina 
The CEsophagns opens directly into the patmch, which igM 
I lined by a smooth, not papillose, epithelial coat. From it§ 
LwaUa, at least two sets of diverticula, with comparatiTdl 



narrow moutha, are developed. These, the so-called " water 
cells," serve to Btrain off from the contents of the pannch, 
and lo retain in store, a considerable quantity of water. 
The reticulum is shwT>ly defined from the rumen, and com- 
nmnicates with it by a comparatively small apertnre. The 
(esophageal groove is bounded by only one ridge, which lies 
upon its left side. The paolteriuni ia reduced to a mere 
tubular pHseage, without lamince ; and the abomasnm is 
large, and has the oi'dinary structtire. The pyloric end 
' of the duodenum is coneiderahly dilated, and has bem 
taken for a division of the atomach. The otsenni is short 
and simple. By a remarkable exception among the Jtfom- 
mtdia, the red blood corpuscles are elliptical. The foetal 
villi are scattered evenly over the chorion, ao that ttw 
placenta is diffuse. 

While the Tragulidm connect the typical Buminnnta -wit^ 
the non-ruminant Artiodactyles, the CavielidcB, on Vba 
other hand, link them with Maerauehsnia and the PerUto- 
dactyles. 

The Gamelidce are at present represented by two veiy 
distinct groups — the Camels of the old world and the 
Llamas of the new. They occur in the fossil state as far 

II. The ToxoDONTiA. — Iliis order has been founded for 
the reception of the large extinct Mammal (Ibamifon), remains 
of which have been discovered in the later tei-tiary deposits 
of South America. 

The snpraoccipital surface of the massive skull slupes 
obliquely upwards and forwards. There are Buproorbital 
prolongations. The zygomata are very strong and arohedi 
and the bony palate is very long. 

In the upper jaw there are two small, inner, and two 
large, outer, incisors. In the lower jaw there are six incisors. 
In the mandible there are canines in the middle of the in- 
terval between the incisors and the erindera. In the upper 
jaw of the adult, only indications of the former existence of 
aiFeoii for canines remain. The grinding t«etb are seven 
oa eadi side above, and bis. cto. eaa^ sluli&^j^v . 'Uunif axe 



THE 



I greatly bowed {whence tbe name of tlie genuB), bo as to 
'be convex outwards and concave inwai-da. They grow 
from persistent pulps, ajid the enamel is absent apou their 

The eeatra of the cervical vertobi« have flattened arti. 
ciilar faces. The doraolumbar vertobi-ffi and tlxo Bacrum 

tare not known. The ribs are epongy internally, like those 
of ordinary MammalB, not compact, as in the Sirenia. 
The scapula has a very large Bupraapinous foaaa, as in 
TapiroB. There is no acromion, and the coronoid is vetj, 
smaU. The humerus and the ulna are very ma; 
the rest of the foi-e-limb is unknown. The femur 
of aJiy third trochanter, and, like the tibia and astragali 
presents a good many points of resemblajice to the ci 
sponiling bone in the Elephants. 

It ia a curious comment upon the pretension to re 

Iatruct animals from mere Eragmenta of their bonea 
teeth which some have pat forward, that although we know 
the skull, the dentition, and the most important of the limb 
bones of Toxodon, no one ventui-es to predict the eharactera 
of its feet, still less to aoy ajiything about its internal 
organization. Even its zoolt^cal affinities are extremely 
doubtful, and it is hai'd to say whether Ibicodon ia merely 
an aberrant TTngulate, or whether it ia the type of a ne 
i„ order. 

ni. The SiBENiA. — As has been already said, nothing 
mown of the placentation of this email but importanC 
t. group of Mammalia, all the existing forms of which are 
f aquatic in their habits, frequenting great rivers and their 
I estuaries ; ami. are devoid of hind limba, while the integ^- 
r jnent of the caudal end of the body is produced into a 
I flattened horizontal fin. No dorsal fin ia ever present. 
r The demareation between the head and neck ia but ob- 
it Bcurely marked, and the foi-elimbs are converted into 
I paddlea, upon which only rudimentary noils are developed. 
Scanty briatlea cover the surface of the body. The snout 
' I fleshy and tumid, and the valvular nostrils, which ax<t 
txieeOj distiact from one Koot^Mg:, wee a».\»a&»a. *asQ»»i«t- 



^ 



388 THE ANATOMY OF VBETBBRATED 

ably above its termination. There ie a well-developed 
third ejelid, the pinna of the ear ie absent, and the 
mamniiB are tliorwjic; a oirciimatance which Las probably 
not a little contribnted to the origination of the mjtha 
respecting the existence of mermaids. 

The Sirenia were formerly nnibed with the Wliales and 
Porpoises a« Oetacea Jierbivm'a. Bnt their organization 
differs from that of the true Cetaeeans in almost every 
particidar, while they are closely allied with the Uhgidaia. 

The cervical vei-tebrte are reduced to six in one genna — 
MajtatuB. The bodies of these vertebrte are always com- 
pressed from before backwards, but they are never all 
aniyloaed together (it is rare for any of them to be thus 
nnitedl, and the second has a distinct odontoid process. 
The dorsal vertebrse have broad and depressed spines, and 
may be aa many as seventeen or eighteen in niunber, while 
there are not more than thi'ee lumbar vertebrEe ; and the 
hindermoat of these even is probably to be regarded a* 
sacral. There aa-e twenty or more caudal vei'tebne, the 
terminal ones being not polygonal, but depressed, with 
well-developed processes. 

The Kygopopbyses of successive vertebrffl arfcicalat« to- 
gether in the dorsal region ; but, in the lumbar and candal 
regions, the postzygapophyses disappear and the prezygo- 
pophjsea are small, and neither overlap, nor embrace, the 
spine of the antecedent vertebra. The posterior moiety 
of the spine thus acquires considerable flexibility. There 
is no true sacrum, the vertebra called " sacral " being only 
determined as such by its connection with the rudimentary 
pelvis. Strong subvertebral chevron bones are placed 
beneath the interarticular cartilages of the caudal vei-t«bra. 
The heads of the ribs articulate with the centra of all 
the vertebnB. The bodies of the ribs are very thick. 
rounded, and have a remarkably dense and laminated etrnc- 
ture. The narrow and elongated sternum is an nndivided 
mass of bone, and is connected by ossiiied sternal riba 
the anterior three pairs of vertebral ribs. 

In the skull the elongated and subcyllndncal form 



THE SIKSNIA. 



eranial cavity is -worthy of notice, ae it etrongly oonfcrasto: 
with the form of the bi-ain-caBc in the Cetaeea. The Bnpra* 
Dccipit^ ia very laj'ge and slopes upwards and forwards 
ft long way on to the upper enrface of the skall; bnt it does 
QOt aeparate the parietal bones ; which, as usual, unite in 
the sagittal sutui-e. The frontals are prolonged into broad 
supra-orbital processes. The naeol bones are abortive. ajiA, 
a the dry skull, the external nares are very wide and look, 
upwards. The tympanic hone is a thick hoop, ankyloaad 
with the periotic bones, and readily comes away from the 
afcull with them. The zygoma ia enormously stout. The 
premaxilliB constitute a large portion of the boundary of 
the gape; and the lower jaw has a high ascending portion, 
with a lai'ge coronoid process. 

The scapula has a distinct epine occupying the ordinary- 
position. There are no clavicles. The humorua has its 
distal end fashioned into articular surfaces, upon which thft 
radius and ulna are freely movable. The pollex is radi* 
mentaiy, and the other digits have no more than threw., 
phalanges each. 

The pelvis is rudimentary, the bonea which represent 
the oasa inncnninaiit being connected by their proiimal 
ends with the transverse processes of the last of the pre- 
caudal vertebra. They are disposed vertically to the 
of the body. No trace of the hind limbs has been observi 
m any of the existing Sirenia. 

The premaiillary region of the palate, and the 
Bponding em-face of the mandible, are coated with mam- 
■.miUated and rugose homy plates formed of hardened 
■ epithelium ; and, in the extinct genus Bhytina, these plates 
e the only masticating organs, as there were no teeth. 
In Hidicfire {the Dugong), thtre are teeth which have no 
vertical aucceasors. foi-m no roots, and are devoid of 
enamel ; while, in MaTUttite, there are milh molars, and the 
grinding teeth are enamelled, and present crowns with 
L.doubie tiuns verse ridges. 

The adult Manatee has no incisors. In the Dugong 
' ' 'a tjw maitdil^a of the atka^ ^j 



] 



pre- 



dW THE ANATOMT C 

male has two tnak-like inciaorB which project from their 
socketa in the premajillfe ; while, in the femnle, the tusks 
remain coneealed in their alveoli. 

In the fffital state, hoth SaKcore and Manatux have in- 
eisora in the mandible as well as in the premasillse. 

The stomach is divided into two portions by a, median 
conatriction, and. its cardiac end is provided with a. peculiar 
gland. Ita pyloric end, in some species, gives off two cceca. 

There is a ccbciuq at the junction of the large and small 
intestine. Salivary glands are well developed. The apical 
portion of the eeptuim ventrietttorv/m, is deeply cleft, so that 
the ventriclea are separated from one another through 
about half their extent. 




Vfe, 103,— DorBtt! view of the heart of & Dugong (tralitm\,U 

being laid open. fl.H., right ventriolei i.. r,, fef t veutricle. 
left superior venscnvn. T-cr. A, right superior vena ovi . , 

ven» cava inferior. F. o. H., the inner end of a eoicsl divert] oulum 
of the tight auricle, inio which a Btjle is inlroduoed, and which 
represents the foramen ovale. O., the auricular «eplutn. 

There are two auporioi- cava! and a Euatachian valve. 
Extensive arterial and venous retia mirahilia are developed 
in Manatvs. In consequence of the great length of the 
thoraeic region and the brevity of the stemiim, the dia- 
phragm takes a very niiUBual course, extending very 
oUi^a^fron ba£ore bnokw&rda, aod ma^ig ib» t^ggr 



THE CETACEA. 391 

part of the thoracic cavity to extend posteriorly over 
almost the whole of the abdomen. The greatly elongated 
lungs fill this part of the thoracic chamber, while the broad 
heart lies in its anterior and sternal portion. 

The arytenoid cartilages are not prolonged as in the 
Cetacea, A broad and high epiglottis is capable of covering 
the glottis completely. 

There is no third bronchus. 

The cutaneous muscle is largely inserted into the hu- 
merus, and the sub-caudal muscles extend forward as far 
as the posterior lumbar vertebrae. The chief muscles of the 
antibrachium and manus are present. 

The male Sirenia possess vesiculse seminales. The uterus 
is two-homed. 

There are two living genera of Sirenia — the Dugong 
iSalicore), which is found upon the shores of the Indian 
Ocean and of Australia ; and the Manatee {Manatus), which 
is confined to the South American and African borders of 
the Atlantic. 

A third genus, Mhytina, which had a coriaceous integu- 
ment almost devoid of hair, and possessed no teeth, 
abounded in Behring's Straits less than a century ago. 
It is now altogether extinct. 

The Miocene genus, Salitherium, appears to have pos- 
sessed distinct, though small, hind limbs. 

lY. The Cetacea. — In this order of Mmn/malia the form 
of the body is still more fish-like than in the Sirenia, 
There is no trace of a neck, the contour of the head 
passing gradually into that of the body. A horizontally 
flattened caudal fin is always present ; and, very generally, 
the dorsal integument is produced into a median, laterally 
compressed, dorsal fin. The body is encased in a thick 
smooth integument, beneath which a very thick layer of 
fat is deposited. Hairs are almost entirely absent in the 
adult state. 

As in the recent Sirenia^ the anterior limbs alone are 
present. Externally they do not present any indication of 



392 THE ANATOMY OP TERTEBEATED ANIMAiB, 

diviaion into bra^lnnm, antebrachium, and manns, but have 
the form of & broad flattened pnddlo, witbout any vestiges 

The one or two apertures by which the canity of the 
nose opena extei-nally, are itlways situated at the top of the 
head, and far removed from the eitremity of the snont. 
Thoro ia no third eyelid, and the rery email auditory aper- 
tures are totaUy devoid of any pinna- The teats are two, 
and, in the female, are lodged in depresaiona on eacL tdde 
of the vulva. 

The articular surfaces of the centra of the vertebrw are 
flat.and the epiphyses usually remain distinct for along time. 
The spinal colnnm, as a whole, ia remarkable for the 
shortnesa of its cervical, and the length of its himbar region, 
there being sometimea a greater number of lumbar than of 
doi'sal Tertebne. There ia no sacrum. The caudal vertebras 
are only diatingaishable from the posterior lumbo-aacral 
vertehne by their chevron bones. The second vertebra nf 
the neck is devoid of any odontoid process; and it rery 
commonly happens that more or fewer of the cervica] 
vertebrie, the bodies of which are often so short aa to be 
mere diaca, are onkylosed together, either by their archea, 
or by their centra, or by both. The centra of all the suc- 
ceeding vertehrtB are lai^e in proportion to their arcliee, 
and the inter-vertebral fibro-cartilages are exceedingSy 
thick, BO as to confer great flexibility and elasticity on the 
spine. The arches of the hinder dorsal vertebra, uid of 
those of the lumbar and caudal regions, are not articulated 
together by zygapnphyaea. The centra of the posterior 
caudal vertebi'S lose theii' processes and become polygonaL 
Very few of the riba become connected with the sternnm 
at their distal ends; and, in contradistinction to what 
happens in most JUammalia, the proximal ends of the 
majority of the ribs are connected only with the transveree 
processes of the vertehrffi, and not with their bodies. 

The skull is even more remarkably modified than the 
veilebral column. The brain case itself has a spheroidal 
form; nlule the jaws are greatly prolonged, the priaci|Al 



Wilargement of tte upper jaw taking place m the region ' 
%hich lies in front of tlie nasal aperture. The boBis cranU, 

I whole, is remarkably broad, and ita npper surfftoa J 
eoncave fi'om before backwards, the tella turcica beingr very j 
slightly indicated. The parietal bonea aj^ comparative^ J 

lall, and do not meet in a a^ttal suture, as they do ia 
other Mairvmalia ; the supinoccipital, with an interparital 
bone, being interposed between them, and extending for- 
vorde so aa to unite with the frontala. Each fi-ODtiil 
lione ia produced outwards into a great bony plate which 
rs the orbit. The sqtiamosal bone eenda a very large 
«nd atout zygomatic process forwards to meet this anpra- 
orbitiil prolongation of the frontal. The proper jugal 
bone, on the other hand, which bounda the orbit below, 
s eiceedingly alender. The veiy large maiilla extends 1 
backwarda and outwaids in contact with the frontal, or ] 
even overlapping the greater part of its surface; and it I 
atretches forwai-da to very near the anterior end of the J 
anout, 80 that almost the whole of the gape ia bounded byA 
thenuixiUa. 

The premaailliB, on the other hand, though very long, ' 
inaamuch as they occupy the whole length of the jaw ii 
Middle line, from the anterior nasal aperture to the end at' ' I 
■the snout, are almost entirely excluded fi-om the gape. 

The nasal bones are alwaya short; and, aometimea, i 
,«iere bonjtuberoaities united with the frontal bones behind 
'tiie anterior naaol aperture. The turbinul bones are almost 
, always rudimentary, and the nasal passages ai-e nearly ver- 
'tical, in consequence, for the moat part, of the inidinian- 
tary condition and shortness of the nasal bones. 

The i>eriotio bones are loosely connected with the squ*- 
~ moeal and tympanic, and are usually united with the other 
bones of the skull only by cartilage, so tluit they fall out 
veiy readily in the dry skull. The tympanic bonea are 
commonly of very considerable size, thick and scroll- 
shaped. 

The lower jaw haa hardly any coronoid process, s 
lamua has no perprnidioulur portion, the condyle I 



394 THE ANATOMY OF VEETEBKATBD 

sitnated upon its posterior extremity. The body of the 
hjoid is B. veiy broad plate of bone, and haa two pair of 
stout well-osaified comna. 

The Cetaeea are devoid of clavicles. If the epine of the 
scapula is present, it ia a low ridge situated close to the 
anterior edge of the bone ; but it commonlj terminates in a 
long SiCroniion process, and, Bometiniea, there is a c<hi- 
BpicuouB, straight, and flattened, coracoid. The humcme is 
ehort, and the articular sni'faces at its diHtal end are, in 
all recent Cetaeea, fiat facets inclined to one ajiother at 
an angle. The ulna and the radina are short, laterall; 
compressed bones, ■without any moTement upon one another ; 
and, in all recent Cetaeea, they are not freely moTable npon 
the humeruH. The carpus ia often imperfectly oeaified. 
When the carpal bones are complete, they are polygonal 
and imbedded in a fibrons tissue ; not united by articn- 
lations provided, with synovial membranes. The digits do 
not exceed five in number, but there are always : 
than three phalanges in some of them. 

The pelvis is represented by two bones which lie parallel 
with the axis of the vertebral column, give attaehment to 
the coi'pora cavernosa in the male, and, therefore, probably 
represent the iachia. They are elongated, convex upwai^ 
and concave downwards, and are connected with the Tert«- 
bral column only by fibrous tissue. In some few Cetaeea 
(BaltETU/idea) ossicles, which lie on the outer side of the 
pelvic bone, appear to represent the femur, but no f iirther 
indication of a hind limb has been discovered. 

In most of the Cetaeea, the muscles which, in other 
Manvmalia, move the antebrachium and the manus, are 
absent, those which move the humerus upon the shoulder- 
blade being, alone, represented. 

In no recent Cetacean have the teeth any vei-tical s 
cesHors, nor more than a single root. The alveoli are often 
incompletely separated from one another. The number of 
the teeth varies very greatly, but they are almost always 
nearly uniform in character. There appear to be no salivary 
glands. The stomach ia complicated, being divided. intOr i 




I 



THE CETACEA. 3!>5 

"at fewest, three ehambere, of wbich. tte first is a kind of 
paxmoh lined by a, thick epitheliam. while the second and 
tlie third are more elongated, the last stomach being that 
in which digestion takes place. 

The arteries and veins form great plesneea, or retia mi- 
rabilia, and these are especiallj conspiiiiioua in the cavity 
of the thorax, upon each side of the vertebral column, and 
in the intercostal spaces. 

The soft palate ia remarkably long and mnsoular. The 
epiglottis and the arytenoid cartilages are more or less 
produced, so as to give the glottis the shape of a fnnnel, 
the apex of which is embraced by the soft palate, in such 
9 to form a continuous air-paseage from the 
posterior nares to the larynx, on each side of which the 
food passes. The very short trachea, before it divides 
into the bronchi, gives off the Ho-ealled " third bronchus" to 
the right lung, as in the Bears, Walruses and Buminants. 

The kidneys are deeply subdivided into lobtdee. In the 
male the t«8tea always remain in the abdomen, and there 
vesicnlffl seniinales. The penis is devoid of a bone. 
The nteras of the female is deeply divided into two homa, 
and the villi of the fa;tus are scattered over its chorion, 
aa in other mammals with a diffuse placentatioru 

The Cetacea are divisible into thi-eo groups ; the Bal/e- 
•aaidea, the Dfbphinoidea, and the Fliocodtmtia* 

a. In the BaJtenoidea the nasal chambers communicate 
with the cKterior by two apertures, which are capable of 
being ahat at the wiU of the animal, and are called spira- 
cles. These are not connected with any saccular dilata- 
tions of the nasal passages, situated between the skull and 
the integument. 

In the spinal column, no rib has a complete neck and 
capitulum. the heads of even the most anterior ribs being 
nnited with the bodies of the vertebne only by ligament. 
The chief connection of all the ribs therefore, and the only 

» f 

CHOQ 



i 





unites only with, tlie first rib, and the union is direct, q 
that there are no etemocoatal nbe. 




Fig. 105.— "Ear bones" of the adull; Balana 
witbln in tlic upper figure ; from witJiout in 
. — v: 1. .. asternsl anditory meal 



ofth 



BQ'loid proceEji 



; Sty., oBsifleil r 



The Bkull (Fig. 104) is esceediogly large in proportion to 
the body, anil nearly Bymmetrical. The nasal bones, Mi., 
though short, axe longer, and more like those of ordinary 

imals, tliaii is tlie case in other Cetacea. The maxilloi, 
Mx., extends ontwards in front of the great anpraorbital 

esB of the frontal, Fr., but it does not cover the frontal 
bone. There is a distinct lachrymaL Each ramus of the 
mandible, 3f II. , is convex outwiirda and concave inwardsi 



398 THE ANATOMY OF TEKTEBRATED AmMAiS. 

and the epa*e between tlie rami of the mandible U very 
much greater than the width of the maiillo-premasillary 
part of the Ekull. which tapers to its anterior end, and 
ia more or less conTCi upwards and concave inferior!;. 
The two mmi of the mandible are connected only by 
ligament at the symphjsia. 

Minute teeth are developed in fcetal Balcenidie, but are 
Tety soon lost, and their place taien by the so-called Whale- 
bone, or Saleen plates. Each of these is triangular, with a 
thick, smooth outer edge, somewhat concave from above 
downwards, which, in the natural position of the plates, is 
nearly vertical, and ia corered by the great lower lip. The 
npper edge of the plate, also slightly concave, is attached 
to a transverse elevation of the giun covering the palate. 
Tascular papillfB extend from this ridge into cavities of cor- 
responding dimeiuionB, which he, parallel with one another, 
in the baleen plate. The third side of the triangular baleen- 
plate, somewhat convex and sloping from the middle line 
above, downwards and outwards, gives origin to a. taa<a\xx 
o£ filamentous processes, into which the baleen appears to 
be, as it were, frayed out. When the mouth is shut, these 
frayed edges of the numerous and close set baleen plates, 
which are longest in the middle of each series, and shorteHt 
at each end, enclose a cavity, the bottom of which ia occn- 
pied by the large and fleshy tongue. By raising the 
tongue, whatever sohd matters are inclosed in the month 
can be forced back into the pharynx and swallowed ; while 
the water in which they were suspended is driven ont 
between the baleen-plates. The Whale feeds by putting 
this gigantic strainer into operation, as it swims throagh 
the shoals of minute moUnscs, crustaceans and fiahea, which 
are constantly found at the sui'face of the sea. Opening 
its capacious month, and allowing the sea water, with its 
multitudinous tenants, to fill the oral cavity, the Whale 
shuts the lower jaw upon the baleen plates, and straining 
out the water through them, swallows the prey stranded 
upon its vast tongue. 

a of the BaUeaoidea, e. g., Babsna rorirafai, Qta 



I 



THE DEI.FaiN01SEA. 

cricoid cartilage anil the rings of tie trachea are 
plete in front, and a large air sac ia developed 
cricothyroid space. The Balienoidea poaaesa olfaiCtoiy 
nerves and a distinct, though small, ulfactJ^rj apparati 
The sclerotic coat of the ejeball is enormouslj- thick, and 
the optic nerve ia eurrounded by a rete-mirabile. The tym- 
panic membrane ta connected with the malleus hy ligament. 
The semicircular canals are very small, but the cochlea in 
large, and makes only li turns. The muscles of tba 
antebrachium and manua ure not altogether abaent. 

The Right "Whale (Balwna), and the Fin-fiahea (Kepa. 
piera, BaUenoptera, &c.), belong to this division. 

b. In the Delpkinoidea the nasal chambers open by only 
a single spiracle on the top of the head ; and saccular 
dilatatiouB, of various dimensions, are developed from the 
walls of the pasaage which connects this aperture with the 
bony naso- palatine passages, and lie between the integu- 
ment and the outer surface of the skull. 

More or fewer of the anterior ribs have beads and neck^i 
the capitula articulating with the bodies of the vertebrte, 
in other Mammalia. The elongated sternum ia, almost J 
always, composed of several pieces arranged in a Ic 
'tndinal aeriea ; and cartilaginous, or ossified, sternal 
are preaent in greater or smaller number. The nasal boneStl 
which are very short, and have their upper surfaces tubercl 
like, are more or leas asymmetrically developed, as are also 
the maxilhe; so that the facial part of the skull appears 
distorted. The maxilto are expanded behind, and cover 
the orbital process of the frontal bone wholly, or pais 
tlally, The lachrymal bone is usually small and confluent 
with the slender jugal. but it may he large and distinct. 
The rami of the mandible are not arcuatal outwards, and 
they become united in a. longer, or shorter, symphysis. 
The mandible, as a whole, ia not sensibly broader than the 
corresponding portion of the masillo-premaiillary part 
the skull. 

Teeth always etist after birth, and are never replaced 
baleen plates. They are usually numerous, but eometi 



rtof^^l 

1 



40() THE ANATOMY OP VBETEBKATED i 

few anil deciduous. Occasionallj, onl; one or two teetli | 
persist, and tlieue, as in the N'arwhal, ma; take the form of | 
immenBeij elongated tuaka. 

To this division belong the Physeteridte, FlaianieticUe and I 
Delpkinid)E. I 

The PhyeeteridiE poaaeas functional tcetli only in the 
lower jaw. The aaymnietrj of the skull is strongly pro- I 
nounced; and, in the Lkilnlt, the maiillai'y and frontul bones i 
are produced, ao as to form s. sort of busin upon the upper I 
and anterior surface of the akull. The pterygoids loeet 
in the middle linu below, and the mandibular symphysis 
ia sometimes extremely long. 

The greater number of the cervical vertebne are anky- 
losed. The hinder ribs lose their tubei-culor, but retain 
their capitular ai'tioalation with the vertebite. The costal 
cartilagea are not ossified. The pectoral Umba are small, 
and a dorsal fin is usually present. 

The proper Sperm "Wbalea (PhyaeteriTicE) have an enor- 
moua head, with a quadrate, truncated snout, at the anterior 
Buperior angle of which the spiraole is placed. The teeth I 
become fidly developed only in the lower jaw. The cranial 
baain is immense, and is filled by a looae connective tissne, 
in which the peculiar fat known as epei-niaceti ia contained. 
Ambergiia is a sort of bezoar, found in the alimentary 
canal of the Cachalot, and seemingly derived from the fatly 
matter contained in the Cephalopoda on which the Cetacean 
feeds. In the other gi-oup of the Fhyseteridm — the Ziphiiita 
or Rhynchoatti — to which the Bottlenosed Whale (Hypejvo- 
don) belongs, there are only one or two pail's of fully formed 
teeth in the mandible. Some recent and many fosul i 
(middle and later tertiary) genera of these Cetaceans are i 
remarkable for the elongated rostrum formed by the solid ' 
ossification and ankyloaia of the ethmoid, premaxillie and 
maxillre. 

The FlatamiiitidiE are flnviatile or cstmirine Ceiacea, which 
occur in the (Jaugea and in the rivers of South America. 
The cervical vertebra are not ankylosed, and the costal car- | 
tilagea are not ossified. The tubercula and capitula of the 



THE DELPHISOIDEA. 




OF TEBTE SEATED A 

ribs blend together posteriorly. The aymphjeia of the 
maniiibles ia eitremely long and the jawB are narrow. Ku- 
mui'Duateethwith compressed flings are found in both jaws. 
The eyes are small, and in Platanieia they axe rudimentary. 

In the Selphimdai lastly (Dolphins, Porpoises, Gram- 
puses), the teeth are usually numei'oUH in both jaws, though 
the ffarwhal is aa exception to this mle, as has already 
been mentioned. 

The anterior cervical vertebrte are generally ankyloaed 
together. The posterior ribs lose their capitula and become 
articulated only with, the transverse processes of the ver- 
tebriB, The costal cartilagea are well ossified. The eym- ■ 
physis of the mandible docs not eseeed one-third of the 
rami in length, and the frontaJ and maxillary bonea are 
not especially produced upwards at their edges. 

As the common Porpoise (Fhoeiena eomtrmma), -whioli 
is a member of this group, is the Cetacean which is most 
likely to come within rea<;h of the student, it may be useful 
to speak at some length of its more interesting anatomical 
peculiarities. 

The adult animal is usually about five feet long, and is 
covered with a smooth integument upon which no hair 
is to be discovered, though a few hail's are visible about 
the mouth in the young animal. The contour of the 
anterior part of the Lead is very convex, and presents, in 
the middle line, the spiracle or blowhole, which baa the 
form of a crescent with the points turned downwards and 
forwards. The eyes are small and placed low down, close 
to the posterior end of the gape of the mouth, which is 
bounded by dense and rigid lips. The aperture of tlie ear 
lies about an inch and three- quartcTB behind the eye, and 
is so minute as to be discovered with dif&culty. The 
genital aperture is placed a long way in front of the anus 
in the male ; while, in the female, the interval, in whicli the 
foBsce which lodge the teats are situated, is muck less. 
There is a conspicuous vertical dorsal fin in addition to the 
flattened caudal fin. Immediately beneath the skia is ft 
thick layer of blubber, as in other Cetacea. 



THE SKELETON OF THE P0KP0I8B. 403 



In the spongj texture of all the bonea, the abserico ot . 
medullarj cavities in thoac of the liniha, and in the long J 
persistent separability of the epiphyaea of the centra of the | 
Tertebrffi, the Porpoise resembles other Cetacea ; as it does 1 
the ahortneas of the cerrical, and the length of the 1 
Inmbar, region of the spinal column. 

The seven cervical vertebra are all antylosed t<^etliei^ .] 
and the atlas, which ia very large in proportion to the rest, ] 
OverlapB them above and at the aides. The centra of the I 
hinder cervicals are ao abort ajid broad that they are 
platea of bone. There are twenty-eight dorso-lumbar verte«-3 
bne, of which fifteen are dorsaL In aU but the most cmteriar' I 
of these vertebne, the zygapophysea are abortive ; and long 
accessory processed, developed from the front part of the 
nenral arches, loosely embrace the spine of the vertebra in 
front. This arrangement, together with the thickneas of 
the intervertebral ligamenta, gives great flexibility to the 
fipinal colunn. The transverae processes of the hinder 
dorsal, and of the lumbar, vertebra are very long. There 
are five pairs of true ribs. The sternebne aaikyloae into 
an elongated stemmn. The anterior caudal vertebiiE are 
provided vrith large chevron bones, and their transversa 
processes eihibit notches through which branches of the 
■orta pass. 

In consequence of the globnlar form of the brain-case, 
and the prolongation of the jawa, the skull has a flask-like 
"ahape. There is a alight want of symmetry about the 
tase of the upper jaw, but it is hardly appreciable. 

In a longitudinal section, the flatness ajvd the upwardly 
concave contour of the base of the aknll ; the ejttreme 
Bhallowneas of the sella turcica ; the presence of an ossified 
tentorium ; and the broad imperforate anterior wall, in the 
;place of the cribiiform plate of the ethmoid, are striking 
features. The synchondrosis between the baai- and pre- 
iflpbenoid ia persistent. On the base of the akull the basi- 
«OCipitaI givea off great proceasea outwarda and downwarda, 
io form, together with a paramastoid prolongation of the 
ipital, and the squamoaal, a ohamber in which the 



404 1 

ankjloBed tympanic and periotic bones are contained. 
The ei- nnd supra- occipitaJa, together with the inter- 
parietals, form the whole back waJl and middle of the roof 
of the cranium, separating the parietala completely, and 
the frontak largely, and reaching the nasaJ hones. 

The ha»i-Bphenoid is wikyloHed with the amall and almost 
horizontal aliaphenoidB, and there aj'e no sphenoidal ptery- 
goid proceasea. The parietalB aje small, and occupy only 
the under and lateral portions of the hrain-cafie. The I 
frontal bones are very broad and espanded, and are com- 
pletely ankyloaed together, where they form the front wall 
of the hrain-caae. Posteriorly and above, they diverge to 
receive the interparietal. The supra-orbital processes are 
extremely lar^e, and are directed forwards and ontwiirdB, 
not backwards and outwards, as in the Whalebone Whales. 
The greater part of the superior surface of the fi-ontals 
and of their orbital proceasea is rough and covered over by 
the expanded maiillarj hones, which allow only a narrow, 
transverse, smooth, band-like stu-fsce, formed by the frontala, 
to iie seen on the upper and anterior region of the akulL 
The rough surface is marked by two shallow grooves 
which paSB from below upwards, and are convex towards 
one another and to the middle line. Corresponding grooves 
exist on the under side of the expanded proximal ends ol 
the maiillarieB: and when these are in their naturalpositions 
the coadapted groovea form two canala, which are blind ii 
front and ahove. These, in the natural state, are full of 
air and communicate with the air chambers at the base of 
the skuU and with the Eustachian tubes. 

The narrow premaxilhe are ankyloaed with the i 
margins of the maxiUffl, and coutribnte only a very small 
portion of the alveolar margin of the upper jaw. The 
alveoli are not completely sepui-ated from one another. 
The pterygoid bonea do not unite in the palate. They have 
a peculiar excavated form, and are notched for the passage 
of the ends of the Eustachian tubes into the nasal passages. 
These are nearly vertical and are separated by the large j 
and atrong vomer. Their superior aperlures arc left quite J 



rimcovered in conaequenee oE tlie amftU size, tubercular form, 
and backward position of the nusal bones. The equiimosal 
ia relatirelj smiUl, but liaa the characteristicaUy cetacean, 
lai'ge, zygomatic process; this extends forwards nearly to J 
the posterior end of fche supra-orbital process, and ^vsi f 
aittaclunent to the slender ju gal. 

The periotic bones form a, dense osseous mass, wMch ii 
ankylosed with the no less beavy and thick, scroll-shaped, 
tympanic. Tie para maitoidea of the periotic 
pretty accurately intoarecess of the. chamber which has 
ali-eady been described ; and is thus held in. positio: 
dry skuil, though, it is very easily detached. 

WTien the tympano-pBriolic bone and all the facial bonea 
anoved, only two pair of foramina aie visible 
base of the skull. The anterior pair give exit to the second, 
third, fourth, the anterior division of the fifth and the sixth 
a, and these answer to the optic and sphenorbitaJ fora- 
The posterior pair take the place of the aval, i 
|)08terior lacerated, and jugular foramina, and the pi-fr- [ 
'Condyloid foramina open into them posteriorly. The r 
%f the mandibles are only united by a short symphysis. 
The body of the byoid is broad and heiagonal, and has two 
i«lender, anterior, and two broad and flat, posterior, comua. 
In the natural position the fore limbs stand out from the 
(body with their flat surfaces looking upwards and down- 
iwards i the upper surface being directed a little backwards, 
tuid the lower, a little forwards. The tuberosity of the short 
rus is directed forwards. The carpus contains six o 
seven ossiflcations. The number of phalanges in the digits I 
Ib two, eight, six, three, two, counting the pollex as the first, j 

The pelvic bones aire elongated, slig'htly curved, osseous 
istyles. They lie with their long axes parallel to the vertebi-al 
Wolumn, their convex sides upwards, and their smaller ends 
forwards, within an inch of the centra of the vertebne, 
^heir hinder ends being close to the third chevron bone 
^lbf the tail. The front ends are about an inch apar' 
Sebind its centre, each bone presents a flattened thickenii 
ir the attachment of the ooipns careraoBam of its rade. 



406 THE ANATOMY C 

The cutaneous mnaele is very largely developed and lies 
between two layers of blubber, the thick euperflcial one 
separating it from the skin, and the thin deep lajer from 
the subjacent muscles. It may be said to be dispoeed in two 
broad layers, a dorsal and a ventral, on each side ; theee 
extend from the occipital crest, aad from the rami of the 
mandibles, to the tail. Both these diriaiona send off strong 
bundles to the humerua, which act as powerful adductors, 
abductors, protractors, and retractors of the fin. There ia 
no trapemti, aad the representative of the laM«simu» doni 
is Tety small. A strong occipito-hii,meTa.lU, from the para- 
mastoid to the tuberosity of the humerus, seems t<i repre- 
sent the cleido-mastoid and clavicular deltoid. A costo- 
hamveralia extends from the steraom to the inner tuberoeitj 
of the homeruB. A small coraco-hTodhialia extends from 
the apex of the coraooid to the inner tuberosity of the 
humerus. The fectoralie mojw seems to be represented bj 
a muscle which arises from the sternum, close to the attach- 
ment of the third and fourth ribs, and is inserted into the 
ulna. The triceps extensor is represented by tendinous fibrea 
in which muscle cannot always be detected, which extend 
from the posterior face of the humerna to the ulna. The 
other muaclcs of the fore-arm and aJl those of the msnns 
axe absent. The dorsal muscles form a thick continuous 
mass from the end of the tail to the occiput [ and, on Uie 
ventral side of the spinal column, the sabcandal muscles 
arc similarly continued forwards, as far as the middle of the 
thorax. An igckio-caKdalis passeia, on each side, from the 
anterior chevron bones to the ischium. Between their 
attachments is an aponeuroBiB which supports the anus; 
iachio-cavemoua muscles puss from the iscbia to the corpora 



The diaphragm has no tendinous centre. Its pillars are 
very thin, and, extending between the kidneys and the apine, 
become tendinous, and ai-e attached to the ventral faces of 
the vertebra), as far as the ninth lumbar. A strong fibruns 
aponeurosis is continued back over the eubvertebrai muscles 
bo the pelvio bones. Between these bones and the ends oC ■ 



THE STOMACH OP THE PORPOISE. 



4071 



■the tranaverae processes of the twenty- eighth and twenty* 
ninth vertehre (counting from the first dorBiil) the apcm 
i stout as to form an almoat distinct fibiv3U 
band, which occupies the place of an ihiun. The ureter lis| 
between the ischio-vertehral f aeijia and the peritoi 
The teeth are small and nnmerous, and their c: 
obtuse and constricted. The passage of tho pharjnx i 
divided in the middle, the soft palate being prolonged into 
a muscular funnel, the opening of which closely fits tho 
constricted neck of the long cone into which the epiglottis 
and the arytenoid cai-tilagea are produced. Thns 
arrangement which is transitory in the Marsupial is f 
.nanent in the Cetacean. 

The stomach is diyided into three sacs. The first is lai^, 

DOnical, and lined by a coarse white epithelial coat. The 

, gullet opens directly into it. The second stomach com- 

municates with the first by an aperture which is close to 

irdiac end of the gullet, and is surrounded by a very 

prominent rugose hp. A curved passage about one inch 

Jong and capable of admitting the finger, lined by a white 

. epithelium simile' to that of the first, leads into the second 

■Btomach. The second stomach is lined by an extremely 

yascular and soft mucous membrane, with about ten strong 

longitudinal folds, separated by deep sulci, interrupted by 

transvei'se ridges. A. narrow and carved canal leads from 

this into the third stomach, which has a tubular form and 

is 1>ent upon itself. Its lining membrane is quite smooth. 

I A small, circular, pyloric aperture places 

— munication with the dilated commencement of the duo>J 

I denum, which has sometimes been regarded as a fourth.1 

F stomach. Its lining membrane presents longitudiniiJ rugB9^ 

continuous with those of the duodenum itself. The c 

joined pancreatic and biliary ducts open just beyond the 

dilated part of the duodenum. There is 

demarcation between the largo and small intestines. The 

^ bilobed liver has no gall bladder. 

In the heart the fossa ovalis is distinct, but t 
lisither Eustachian nor Thebesian valve. The vena ci 




408 THE AKATOMT OF VEBTEBKATED ANIMALS. 



inferior is long and wide, but is not especiallj dilated near 
the heart. Muacnlar fibres are not continued on to it from 
the diaphragm. The aoi-ta and pulmonary arteries are not 
dilated at their origins. The arteries have a great tendency 
to break up into plexuses. Thus the internal oarotidB 
form great networks which communicate with vertebral 
plexuses, ezteading tbroughont the entire spinal conaL 
The brachial artery divides into two brauehea, and these 
Bttbdivide into innumerable parallel twigs. The intercostal 
arteries are the chief source of the large thui-acic plexuaes, 
which be at the sides of the vertebral column in the 
dorsal half of the thorax. Finally, an arterial refo mir<d>ile 
Burronnds the caudal aoi-ta. The veina form plexuaes cor- 
responding to, and mixed up with, those of the arteriee ; 
and a very large venous plexoa lies on the subvertebral 
muscles in the abdomen and thorax. 

The respiratory apparatus of the Porpoise presents many 
remarkable peculiarities. The contour of the front part 
of the head, as bounded by the integument, is very convex — 
the corresponding facial region of the skull, on the con- 
trary, is very concave. The interval between the two U 
ocoiipied, in part, by fibrous and fatty tissue; and, in part, by 
a singularly sacculated gpiiracttlar chamber, which connects 
the single spiracle with the double external nares of the skulL 
Two valves, an anterior and a posterior, lie immediately 
above these external nares and close the communication 
between tbem and the chamber, except at such times aa it 
is forced open from below. Each nasal passage remains 
distinct from the other as faj as the valves, the middle of 
each of the latter being fastened to the septum, so that there 
may be said to be a pair of valves for each opeuiug between 
the passages and the spiractdar chamber. Each na«al pass- 
age, after it ceases to be aurromided by bone, sends off two 
diverticula, one forwards and one backwards. The anterior, 
which lies between the anterior valve and the premaxilla, 
is a simple sac, lined with a thin, black, smooth membrane. 
The posterior diverticulum lies between the posterior valve 
and the ethmoid and nasal bones. It ia iBeompletdgr i 



THE MECHANISM OP SPOUTING. 409 

divided by a sort of ahelf, ia pi'oloiiged forwards, ronnd, 
' aad in front of, the anterior valve, and ends bUndtj 

middle line above the anterior sac. The spiracular chamber 
itself is produced, on each side, into a large lateral 
walls of which are raised in strong parallel ridges, and 
covered with a bla«k papillose integument. The walla of 
these sacs are strong and elastic. Lajera of musculac 
fibres pass from the occipital ridge to the posterior lip of' 
the spiracle, and from the edges of the maailla) to its aii> 
tenor Up. Their action ie neceaaarily to open the apirade 
and compress the sacs. There ia no sphincter, the form of 
the spiracle causing it to be oaturaUj shut hy the fitting 
getber of its wiUls, and the pressure of the water upon them. 
When a Porpoise comes to the surface to "blow," the 
shape o£ the posterior, concave, lip of the crescentie spiracli 
doea not sensibly alter; hut the anterior, convex, lip ia 
pulled downwards and forwarda, ita surface becoming some- 
what depreaaed, and ita free edge nearly atraigbt — i 
the aperture, when fully dilated, aasumcs the form of 
half-moon. At the same time, the air ia expelled 
rushing sound. The inspii'atoiy act must he very rapid, 
the spiracle remains open for only a Tory short time after 
expiration ends. When the larger Cetaeea come up to 
breathe, the eitpired vapour suddenly condenses into a 
cloud; and, if expiration commeneea before the spiracle is 
actually at the anrface, a certain ijuantity of spray may be 
driven up along with the violent current of the espelled 
air. This gives rise to the appearance termed the " spout- 
ing " of Whales, which does not ariae, aa it is commonly 
said to do, from the straining off of the sea-water swal* 
lowed with the food, and its expulsion by the noatrils. 

The epiglottis, in front, and the arytenoid cartilages be- 
hind, are prolonged into a tapering tube, dilated at its sum- 
mit into a knob. The muscular aoft palate embraces the 
neck of this knob so closely that it cannot be withdrawn 
without considerable eS'ort. And thus, during life, the nasal 
air-pasaagca and the glottia are kept perfectly continuous; 
while the Porpoise dashes through the water, open mouthed^ 



fter 1 

1 



410 THE ANATOMY 01' VEETEBEATKD J 

after its prey. The point at whict the eitra bronchus tothe 
right lung is giycn off ia separated by four rings from the 
bifuixiatiou of the trachea. The lungs are not lobed and 
their tiasue is very dense and elastic. 

The cerebral bemiapberes are, taken together, broader 
than they are lon^. In the upper view they leave not more 
than a Beventb of the length of the cerebellum eiposed, while 
they overlap it largely at the sidea. The outer fnirface of 
the hemispherea ie extremely convoluted, the gyri being 
nuTuerouB and separated by deep sulci. There is a, well- 
marked Sylvian fiBsure, with a central lobe, or insiila. A 
rudiment of a posterior comu has been observed in the 
lateral ventricle. The corpua callosnm is small, relativdy 
to the size of the hemispheres, and the anterior conimissore 
is almost obsolete. The medulla oblongata, has corpora 
Irapeioidea. The olfactory nerves are wanting — a cii-cum- 
stance which agrees with the entire absence of ethmoidal 
turbinals. The eye has a thick aelerotic, and there is a 
choanoid muscle ; no nictitating membrane is present. 

The external auditory aperture is ao small as to be easily 
overlooked. The meatus auditorius is a narrow undulating 
tube about two iucbea long. The tympanic membrane ia con- 
cave externally ; and, as ia usual in the Cetacea. is connected 
by a ligament with the handle of the malleuB. There JB 
only a small aperture in the stapes. The teiigor lympani 
aiises, as in Carnivores, from a fossa in the periotio ossifi- 
cation. 

The Eustaciiian tube pusses through the notch in the 
pterygoid and opens into the naeal passage on the inner 
side of that notch. Close to its commencement it com- 
municates, by an oval aperture, with a remarkable air 
chamber, wbichextendsbackwarda between the periotio maas 
and the baaia cranii. and forwards to the under side uf the 
expanded part of the maxilla, where it opena into the canal 
between the maxilla and the frontal already described. 
These cbambera, like the bronchi, are generally full of 
nenmtoid wonna. The testes and penis of the male are 
finormoofl ingroportknitotliesiicol ^laaNsjis, T&&-^stu 



TH£ DECIDUATE MAMMALIA. 



I is devoid of a bone, and, ordmarilj, is bent ap in the long | 
P prcputiul ateatli. 1 

' c. The PhocodonUa are represented only by Zeuglodon, I 
Squalodtm, and other large extinct cetae«ane of the tfirtiaiy J 
epoch. These remarkable foesil forms constitute con- I 
necting links between the Cetacea and the aquatic Ciwrii- ^ 
vara. The cervical vertebrte are diatinct and unanky- 
losed, nearly resemhliiig those of the Shynaoceli. The 
candal vertebrte have their transverse procesaea perforated 
veiticuUj, as in many Ceiacea. The dietal ends of tlie . 
xibs are enlarged somewhat as in the Sirenia. The sknll J 
is symmetrical, and the nasal bones, though BtOl short, are '1 
longer than those of any other cetacean. The zjgomatio 1 

IproceBses of the squamosal are large and thick, and the I 
BUpraorhital proceeses of the frontals wide imd expanded 1 
aa in the CetacBo. I 

The scapula appears to have had a spine and acromion 1 
like that of ManatuB. The humerus is compressed from! 
aide, and has true articular surfaces upon its distal end) 1 
although they are of small size. ^ 

The molar teeth have laterally compressed crowns with 
semted edges and two fangs, resendiling those of many 
seals, and Zeaglodoa differs from all the other Cetaeea in 
the circmnstance that some of its teeth have vertical aue- 

Tbe DECIDI7ATB Mammaxia. — These may he subdivideiM 
according to the fonu of the placenta, into two groupaiB 
the Zotutria and the Discoidea. In the former the placentas 
Bun'ounds the chorion like a hoop, leaving its ends free of 'i 
■villi, or nearly so. 1 

In the Diaaridea, on the other hand, the placenta takes the 1 
form of a thick disc, which is sometimes more or less lobad. j 

The mammalia which possess a zonary placcntation are 1 
the Camivora, the Proboscidea, and the Hyraeoidea. J 

Each of these divisions is very closely related to one oJj 
the foregoing. Thus the Camivora approach the Celacea^^t 
the Proboacidea, the Sintnia ; and the Hyraeoidea, th^fl 
Vnffulata. ^H 



412 1 

The ZoNABiA. 1. The Oaenivoba. — In thia order tte 
heud, reltttively to tte body, ia of moderate or small wae; 
tmd liair ia abundant. 

The cervical vertebra are free and unankjioeed, and their 
centra are elongated. The odontoid procesa of the second 
ia well developed. The dorao-lumbar vertebne are almost 
always twenty in number, ■■arely twenty-one or ninetecu. 
The number of dorsal and lumbar vertebrte, reapectively, 
varies between aixteen dorsal and four Iumba.r, and thir- 
teen dorsal and aCTen lumbar. Tho dorao-lumbar vertebne 
are always articulated together by their zygapophysea, and 
there is a complete sacrum. 

The stemebre are numerous and laterally compressed. 

In the skull the nasal bonea are well developed, aud have 
the ordinary form. When supraorbital enlargements of the 
frontal exist, they are of moderate size. The parietals onite 
in a long sagittal suture. The orbit and the temporal 
fossa commumcate fi'eely, the posterior boundary of the 
orbit never being completed by bone. The jugal bone ia 
large and unites by a broad surface with the mayilla. There 
ia a distinct coronoid proceaa, and the long axis of the 
articular surface which, receives the head of the mandible 
ia transverse. 

The hyoid has a small body and many-jointed anterior 

Both pairs of limbs are fully developed, and the tail is not 
provided with a horizontal fin. Clavicles may be absent, 
and, when ossified, they do not occupy more than half tJie 
interval between the acromion and the sternum. The 
scapula has a distinct apine, and a large supra-spinous fossa. 

Neither the hallux nor the pollex are opposable. The 
carpal and tarsal bonea have the ordinary number and 
arrangement; except that, in the carpus, the scaphoid and 
lanare are united into one bone. The terminal phalajigea 
of the digits, which never fall below four in number, are 
almost always provided with sharp and pointed claws. 

The teeth are alwaya distinguishable into incisors, canineA 
^ood molarsi they are lodged in distinct aoeketa, aad tbeir 




THE CAKNIVORA. 413 | 



i axe eoTered with enamel. There are always two ! 
Beta of teeth, a milk and a, permanent dentition. 
a very general rule, there are six incisore aboTe and an \ 
equal number below. The canines are long, curved, and I 
pointed. 

The stomach is simple and undivided, and the eacnm, j 
which ia never large, may he altogether ahaent. 

The liver ia deeply eubdirided and there is a gaU bladden..! 

In the brain, the cerehelliunia never completely covered by 1 
the cerebral hemiaphereB, which are coimect«d byalai^j 
corpus calloBum, and, oiccepfc in the aqnatie forma, by » 1 
weU- developed anterior commiBsore. On the eiteiior of' | 
each hemisphere, there are nanally three distinct convolu- 
tions surrounding the sylvian fiasure. But, in the aquatic 
Carnivora, the gyii are much more miinerous and c 
plicated ; the cerebral hemispheres are much broadei" and 
longer in pi-oportion to the length of thebraiu; and they 
may even exhibit a rudiment of the posterior comu. In all _, 
these respects they approach the Getaoea. 

The inferior turbinal bones are always large and have I 
a complicated form. 

There are no reBicule seminales, and an o» penie is vi 
generally present. The ovaiy is inclosed in a peritoneal si 

The Ca/mivora are divisible into the Pinnipedia, or aqoatit 
Camirorea ; and the FUeipedAa, which are mainly terresfcr 
and cursorial. 

a. In the Fitsipedia the incisors are, with one exceptii 



{Bnkyda-U, the Sea-otter, with i. — ), six in number in eat^'^ 
jaw. 

The hind limbs have the position UBual in mammals, and I 
the tail ia free to its root. The pinna of the ear is fully 
developed. The middle, or outermost, digits of the pes are J 
longest, the hallux being shorter than the otherB, 

Almost invariably, the distal phalanges of both limbs aro I 
provided with clawSj and, in the moat thoroughly camivoronajj 
forms, these clawa are very strong, curved and pointed. ThftfB 
phalanx which support* the claw has a aimilar form, anA. * 









^H 


414 THE AJIATOMT OF VEKTEBBATED ANIMALB, ^^^^ 


plate of bone 


risea from ha base 


OB a short sheath. An 


elastic hganient connecta the base of the ungnal phalanx 

1 ,:f:x 








- ^^^ 






^' 




1 






^5 


1 

i 


^fe 


^^^^ 


^^K f s 


9 

i 




^I^S 




■ 


1 




^^ 




1 




1^ 
1 ^ 


i^'Z^^ 


fi 


^ 




^W ^^^fep 





I THE ANATOMY OP THE DOS, 415 

with tbe middle phalanx, so that when the flexor ■pro- . 
fundus digitorumt is not in action, the ungual phalanx is 
pullod back upon the middle phalanx, and the claw which it 
bears ia retmcted into an integnmentary sheath. 

The olfactory lobes' are usually large and the cerebral I 
hemisphei'CB elongated. 

As the Dog (Caniafamiliaris) is an excellent and eaeilj^ 
accessible example of a fissipede carnivore, it may 1 
useful to mention some of the more important points i 
anatomy. 

The vertebral colnmn contains twenty dorao-lmnbar vi 
tebrffi, of which thirteen are dorsal and seven lumbar, t 
sacral, and eighteen to twenty-two caudal vertebrte. The ' 
atlas has broad and rounded ala;. the anterior margins 
of which are deeply excavated near the roots. The pos- 
terior edge of the spinous process of the axis vertebra is 
almost pei-peudicular and very thick. 

Nine pairs of ribs are usnally connected by stemo-coatal 
cartilages with the sternum, which is composed of eight ' 
laterally-compressed stemebrse. Only two of the three 
ankylosed sacral vertebra) articulate with the ilia. 

As in the Camivora in general, the occipital foramen is 
placed at the posterior end of the skull, and looks almost 
directly backwards. The sagittal and lambdoidal crests 
are greatly developed and meet in a prominent occipital 
epine ; the zygomata are very wide and arched outwajda ; 
and the coronoid process of the mandible is very large. 
The size of these parts is in relation to the magnitude of 
the muscles of the neck and jaws. 

The ramus of the mandible ia nearly straight, the proper 
angle of the jaw being obsolete. A supra-angular process 
projects outwards from the ascending portion of the ramos, 
and takes the place of the proper angle. The articular I 
condyle is much elongated transversely, narrow and a 
from before backwards; and the pre- and post-glenoidal p 
cesses of the squamosal are produced downwards bo 
convert the joint into a oomplote ginglymus and to r< 




416 THE ANATOMY OP TBETEBBATBD ANIMAI.B, ^^J 

the motion of the jaw to the vertical plane. The supra- 
orbital processes of tbe frootalB are small and pointed. Thq 
root of the aliapheaoid is traversed bj a longitadinal canal. 
The tympaniun is bounded below by a convex osaeoui 
wall, which ia termed the hilla. It opens estemally by thfi 
abort external meatns, at the inner end of which is a di'* 
cuiar elevation for the attachment of the tympanic mem* 
branc. A abort distance internal to this frame for tha 
membrane of the drum, a low crest rises from the floo^ 
of the bulla and imperfectly divides it into an outer anS 
anterior portion which communicates with the Eastachiani 
tube, and an inner blind spheroidal cavitj which occupietf 
the greater part of the bulla. The part of the bulla whicU 
forms the floor of this cavity is the result of the oasificatioK 
of a process of the periotic cartilage, while the other pan 
is furBisbed by the tympanic bone. The low crest is 
produced by the conjunction of both. Posteriorly an4 
internally, the periotic region of the bulla presents a cana^ 
through which the internal carotid ai-tery paesea. Th* 
posterior opening of the cai-otid canal looks into the/trroJ 
men laccrum poiliewn, and is not visible without dissectioiU 
There is a large paroccipital process, with a prominent freoj 
extremity; but, for the greater part of its length, it is closely,! 
applied to the back of the bulla. The condyloid foramena 
ia quite distinct from the foramen lacerum posteriim. ^ 
large foramen behind the glenoidal cavity transmits a tuil 
from the interior of the skuU. In the nasal cavity, tha 
ethmoidal turbinals are very large ; the superior turbinaln 
are prolonged into the great frontal sinus, and the inferior 
turbinals unite, in the middle line, with the septum. | 

The clavicles of the Dog are always rudimentary and! 
are generally represented only by a giistly intersection ofi 
the muscles which represent the stemo-mastoid anddeltoicL, 

The olecranar fossa of the humerus is perforated. Tha 
hallux ia much shorter than the other digits. WheiL 
the Dog stands, the metacarpal bones of these digits an' 
neaily vertical ; the basal phalanges are horiKontal ; that 
middle and the distal pbalangea are inclined in the form of' 



THE MYOLOGY OF THE DOG. 417 

a y with the apex (the articulation between the two) 
downwards. The claws are, consequently, raised from the 
ground, the foot resting partly on a thick integumentary 
pad, which lies beneath the basal phalanges ; and, partly, on 
the under surfaces of the joints between the middle and 
the distal phalanges. The distal phalanges are kept bent 
upon the middle ones by elastic ligaments, which pass from 
one to the other, and which antagonise the action of the 
long flexors. The Dog, therefore, possesses the mechanism 
for the retraction of the claws, but its action is not suffi- 
cient to protect them from wear. Fahellce, or sesamoid 
bones developed in the tendons of the gastrocnemius, lie 
behind the condyles of the femur. The fibula is thin and 
closely applied to, but not ankylosed with, the tibia. The 
hallux is usually rudimentary; only the metatarsal, and 
the basal phalanx, being represented by two small ossicles. 
In some breeds of dogs, however, the hallux is f uUy deve- 
loped. 

In the myology of the Dog the insertion of the tendon 
of the external oblique muscle of the abdomen presents 
some interesting peculiarities. The outer and posterior 
fibres of this muscle end in a fascia which is partly con- 
tinued over the thigh as fascia lata, and partly forms an 
arch (Poupart's ligament) over the femoral vessels ; by its 
inner end it is inserted into the outer side of a triangular 
fibro-cartilage, the broad base of which is attached to the 
anterior margin of the pubis, between its spine and the 
symphysis, while its apex lies in the abdominal parietes. 
The internal tendon of the external oblique unites with the 
tendon of the internal oblique to form the inner piUar of 
the abdominal ring, and is inserted into the inner side of 
the triangular fibro-cartilage. The pectineus is attached to 
the ventral face of the cartilage; the outer part of the 
tendon of the rectus into its dorsal face; but the chief 
part of that tendon is inserted into the pubis behind it. 
This fibro-cartilage appears to represent the marsupial bone, 
or cartilage, of the Monotremes and Marsupials. 

The trapezius and the stemoma^stoid coalesce into a single 

2 E 



418 THE ANATOMY OF VERTEBKATED J 

muBcle i and, in the absence of a complete clttricle. the outer 
fibres of the latter and those of the anterior part of the 
deltoid are continuona. In thia way a, muscle which has 
beeaa called levator humeri propriia ia formed. The onto- 
kyoid and the subclavius are absent. There is a traeluio- 
aaromialis and a. dorso-epUmchlea/ru. The atipitiator longnt 
is absent, but there ia a protiahr quad/raiti^. The extetuor 
eomm/Ufiis digitorwm manftg divides into fonr tendons, in 
which sesamoid bones are developed over the articulations 
between the first and second phalanges. The extensor 
primi intemoAii poI2im is absent. The esdensor secwtidi 
intemodii is one muscle with the earfensor indids. The 
flirfejwor miniim digiti sends tendons to the third, fonrth, 
and fifth digits. All these deep extensors have sesamoid 
bonea over the metacarpo-phalaiigeal articnlationa. Thepol- 
maHs longua appears to be absent ; but all the other flexors 
of the manns, even the palmarU brevie, are represented. 
The tendons of the jleiarr polKcie longvs and Jkxor digi- 
iorvm, perforans are united. The divisions which Uie 
conunon tendon sends to the five digita develope sesamoid 
bones, juat before their insertions into the bases of the distal 
phalanges. The fifth digit has its ahduidor,flexor hrevis, and 
opjwneiia; tie poUex, an abdactor, addiieior,fiexor breais, and, 
perhaps, an opponens. The second, third, and fourth digits 
have each a pair of flexorea breves, which represent the 
interoesei, and are inserted into the bases of the proximal 
phalanges, a relativelj large sesamoid being developed in 
each. Each sends off a fine tendon dorsad to the extensor 
sheath. The plantaris is large, and, as in the Pig, its 
tendon passes into the repreaentative of the flexor hrtvU 
digUortim pedw. The tendons of the fietear hallKcU icmgiu 
and flexor perforaiie unite into a common tendon, which 
subdivides into ahps for the digits. 
The dental fonnula of the Dog is i, -^ c. —p.m. ^ 
w.^=42. Thetwoupper inner incisors, on each side, have 
distinctly tiilobed crowns — the lateral cusps of the crown 
ai'iaing from oatgrowths of the ciagitlu/m at its twsei. Hba j 



THE DEKTITIOH OP THE DOG. 419 I 

outer incisor ia larger than the otlerH, and its middle I 
cuap ia very large, -while the outer ia radimentary. Tha 1 
large canine has a strong, curred, pointed crown, tvith a 
longitudinal ridge along its posterior face. The ci-owna (J 
the anterior three premolars are triangular, with a. Bmoott. 
cutting anterior edge ; the hinder edge is also sharp, but ia 
divided by a notch into two lobea, of which the hinder 
IB the Bmaller, These teeth are two-fanged. The fourth 
premolar ia a large tooth. In form, its crown haa a general 
Bimilarity to that of the foregoing; but, firstly, the poe- 
terior lobe is relatively much larger, and pointed, t 
to form an obvioua second cuap; and, Becondly, a strong I 
process of the crown projecta inwards from its anterior J 
end, and is supported by a distinct fang — so that tbia prfe. J 
molar is three-fanged- It ia termed a. camasgial, or i 
tonal, tooth, as it bites like a sciasor-blade against a c 
responding tooth in the mandible. The preceding teetb , 
have cutting crowns; but those of the molai's are broad and 
crushing. They exhibit an outer diviaion, formed by two 
large snbequal cnaps. and an inner division, also presenting 
two cusps, the posterior of which is much amaller than 
the anterior. In addition, the cingulum sends up a stronf 
proceaa on the inner aide of the crown. 

In the lower jaw, the ci'owna of the incisors, the onter ( 
which is the largest, are all trilobed. The outer cusp ii 
stronger than the inner in all, and pai'ticnlai-ly in the outer, 
incisors. The canines resemble tlioae of the upper jaw. 
Each premolar has two fangs and a. sharp triangular crown, 
the posterior edge of which ia trilobed, as in the upper ■ 
pi-emolars ; but the posterior lobe is amall in the fourtb, 1 
which differs but little from, the rest. The first moLir, on I 
the other band, is a large tooth, with a blade-Ulce crown, J 
which bitea against the inner side of the upper fourth pre* ¥ 
molfir, and is called the carnaasial or sectorial tooth of the| 
lower jaw. The crown ia elongated, and presents a large 
^.anterior external cusp, divided into two lobes by a deep 
. On the inner ride of this is a small internal 
The two pufitariar ousps are very much lower than 



ting J 

thai^^^ 

^^ 
'■ 

m 



420 THE ANATOMY OP VEKTBDBATBD ANIMA: 

the anterior ones, and form a sort of heel to the hlude-likei 
anterior portion of the crown. An oblique ridge conneeti^ 
the outer and larger of the two posterior cusps with the' 
small inner and anterior cusp. The second molar has h 
broad qnadricuHpidate crown, the inner posterior cuap being, 
almost obsolete. The crown of the last molar is smalLI 
simple, and obtusely conical. 

It thusappearsthatthesecfoHal, orcomtMsioZ, teethinthff 
two jams differ in their nature, the upper being the last pre-i 
molar, and the lower the anterior molar. The milk dentition! 
of the Dog is d.i. — d.e. —d.m. — ' the "first premolitt"' 

of the adult dentition having no deciduoua predecessor; ikk 
that, in this, as in so many other caaea, it is doubtful whetherl 
it ought to be counted in the milt, or in the adult, denti-j 
tion. The middle deciduous molar in both jaws resemblea 
the hindermost premolar of the adult dentition, and the 
hindermost, the first molar of the adult. The so-called "firBt 
premolar " of the adult, and the anterior molars, appear 
before any of the deciduous molars ai'e shed. 

The ocecum of the Dog is long, pjid folded upon itseH, a 
which respects it ia unlike that of other Carnivores. The 
aroh of the aorta gives off an anonyma and a left sab- 
clavian. 

In the brain, the olivary bodies are inconapicuonB, the 
corpora trape^nndea large, and the corpora tnammillaria 
distinctly donble. The olfactory lobes are very large, and 
expand posteriorly on the sides of the brain into a broiid 
uuias continuous with the gyrua wieinatna, or hippocampal 
lobule. The cerebral hemispheres extend for a considers^ile 
distance over the cerebellum, in the npper view, and overlap 
it laterally. The Sylvian fissure does not extend taon 
than half-way to the median fissure. The surface which 
answers to the insula Is quite smooth. The anterior ends 
of the ealloHO -marginal sulci pass on the npper surfaces 
of the hemispheres, and give rise to the " crucial " sulens. 
There are three principal gyii upon the outer surfaces of 
£ hemispheres i one which immediately bounds the SjItuu 



CLiSaiFIOATION OP THE CAKNIVOEA. 

fissure, one wLich rtma alorg the upper margin of the I 
lieniisphere, and one between tLeae two. The corpna cal* T 
losum is long, and the anterior conuniBBtire well developed. 1 

There is a, muaculug ckoanmdes in additiun to the nsual I 
octiliir niUBcles, and the rudimentary nictitating membrane 1 
is aaid to possess & muscle. 

The ItMBor tympani ariseB from a deep pit above the pro.' 
montorj, and its tendon paesen directly outwarda to tlie 1 
malleui. 

The male is devoid of Oowper'a glajida. The penis Las ft . I 
bone, and the glans becomes swollen during copulation, bq J 
as to prevent the withdrawal of the penis from the vugin&il 
of the female. The ovary of the female is enclosed u 
of the pei-itoneum, and the aiei-us lias long cornua, T^fri'l 
umbilical sac is drawn out to a point at each end. 

The Dogs (inclnding the Wolves, Jackals, and Fos« 
under this head) form the moat central group of the 
Camivora, which may be termed the Cynoidea.'' Prom 
these the Bears, Weasels and Procyonidai depart, on the one 
Land, and the Cats, Civets, and Hjmmus on the other. Tha™ 
former gi»up [Arcloidea} have the cavity of the bulla tynb 
pani undivided by a, septum. The paroceipilal process i 
not applied to the posterior wall of the bulla. The aia 
process is widely separated from the paroccipitaL 
condyloid foramen, is not merged in a common ope 
witli the foramen lacsnim poaticum. The intestinal canal im 
devoid of a ccecum. The large penis has a bone which i 
■Jiot grooved) there are no Cowper's glands, and the prOMH 

' In. the latter group {Aiharoidea) the buUa tympani ie largs V 
md rounded, and the septum, which is radimentaiy in tlwn 
^Jynoidea, is so much enlarged as to leave only a narrnw 

ture of communication between the two cliamberH. Th« I 

baroccipital ia closely applied to the posterior wall uf tha I 

>bulla. The mastoid process ia often obsolete. The tmu- j 

• Sbb Professor Flower's ImpotUiit memoir on Ihe ClumlfldiMlMl rf 4 

B Camirora in tbe Proceedinei of tbe Zoologlc*) Hocinj tat ItXOt — 



422 THE AKATOMT C 






<l;loid foramen opens into a foasa common to it and tht 
foramai Utceruvi poaticwm,. All have a abort ctBcnm. Th^ 
pentH ia Bmall, and ita bone Email, irregular, or abaenlj 
They have Cowper'a glanda and a. well- developed proatate. ] 

I^e Cynoidea are all digitigrade, ajid resemble the Doa 
in their dentition. The Aretoidea. are plantigrade, whifl 
the Aibiroidea are for the most partdigitigrade, but may b^ 
plajitigrade. In dentition, each of these groupa present^ 
Forma such as the Beara on the one hajid, and the Gate cnl 
the other, which may be regarded aa extreme modificataooB 
in opposite directiona, of the tj^ eihibited by the Dog. ' 

In the Beare, the dental formula is the aame ae in tht 
Doga, but the crowns of the teeth are all more obtuse. TU 
sectorial teeth lose their marked charactera, and the molail 
have flat and tubercnlated crowna. The anterior pr* 
molars fall out as age advancea. It ia a remarkable cii* 
cumstantie that the teeth of fnigivorons and carnivoroBi 
Beara exhibit no Bucb diSei'ences aa would lead to a eoa 
pieion of their complete difference of habit, if we wert 
itoq^uainted with theac animals only in the condition of foes 

The Cats have tbe dental formula i. — c. — - 



lit. — = 30. The canines are very long and sharp, 
premolars are like the Boga', except that they are shoipeij 
and that the hiadermost (the sectorial tooth) has lian31| 
any internal proceaa. The single upper molar ia a smafl 
tooth with a flat transveraely elongated crown, and it liM 
within, aa well aa bebind, the great sectorial premolar. li 
the lower jaw, the sectorial, or first, molar ia the lasl 
tooth in tlie seriea. The crown ia a deeply bifurcated bladfl 
representing the antero-extemal cuap of the correepondind 
tooth in the Dog. The " heel " is obsolete. 1 

While the Beara are among the moat completely plantie 
grade of the Cavnivora, the Cata ai-e most entirely digitit 
grade, and the apparatus for the retraction of the imgua] 
phalanges ia so well developed that the claws are coin> 
pletely retracted within sheatha of [the integument, wh^ 
~mal does not desii'e to use them. Tg this end ti 



THE PINHIFEDIA. 

elastic ligaments ave very strong, and the median phalai: 
' I escavated, in order to aJlow of the lodgment of t 
retracted phalanx on one side of it. 

6. The Fimiipedia, or Seals and Walruses, are those Cttfj 
nivora which come nearest the Cetacea, The tail is 
hy a fold of skin which eitends beyond its middle, with tl 
integument covering the hind legs. These are, 
BpecieB, permanently stretched out in a line with the axis^ 
the trunk. Thepiimaof thoearisBmallorahsent. Thetc 

■e completely united by strong webs, and the straight n 

■e sometimes reduced in number, or even altogether ahor- 

ve. The inner and the outer digits of the pea are very 
large. The incisors vary in number and lose their cutting 
form. The premolar and molar teeth are similar in 
racter, and never have more tlian two fangs. There is 
lachrymal hone or canaL 

The brain-case of the cranium is generally much i 
rounded than that of other Carmvora; and,_in son 
the supra-orbital processes of the frontals are very largt 
developed. In both of these characters, and in 
breadth and complication of the convolutions of their c 
bral hemispheres, as well aa in their relatively small olf acta 
ves and anterior conuuissure, the Pinnipedia approac 
the Cetaeea. 

There are three groups of Finnipedia : the OfaridtB, tl 
Trichechid<B, and the P)iocidce. 

1. The Otairidm, or Eaa'ed Seals, are so termed becaUB 
, the ear possesses a distinct though almost m il imnn twyj 
na. These Seals have long nechs, and can stand or 
walk upon aU fours, the hind limbs beinff capable of sup- 
porting the body in the ordinary way, 

~n many respects, these animals are closely allied with the 
Bears ; and by no part of their organization is this more 
clearly shown than by the skull, which in its geoeral 
form, its large supra-orbital processes, the small and rugged 
bulla tympani, the perforation of the alispheaoid by a 
canal, and the presence of a crest on the inner surface t£ 
-the parietals, is extremely ursine. 



THE ANATOMY C 



ANIMALS. ^^H 

.evoid of estemal 



i-24, 



2. The TridwchidcE. or Walruses, are devoid of e 
ears, but reaemlile the OtariAte in their mode of standing 
and walking. The Ekuil reaemhles that of the Bear in tha 
aame reapecte, hut the muzzle is distorted hy the enonnoufl 
development of tte superior canines. The WnlruseB rai 
semble the Bears in another point, namely, in the prc^ 
sence of a supplementary bronchns ; the right bi"OBelm* 
before it reaches the lung, dividing into two trunks, a largd 
and a smaU. The thyroid cartilage is deeply eKCav&ted, in 
front, by a triangular fissore; and the epiglottis is extremel] 

Id the brain, the rcniarl;a.bly large and richly convolute 
liemi spheres cover the cerebellum, and present a 
mentary posterior eornn. The anterior commisauro it 
Bmall, as are the olfactory nerves. 

The dentition of the Walms is extremely pecnliai 
the adult, there is one simple conical tootli in the 
part of the premaxilla, followed by a huge tusk-like cauinj 
and three, short, aimple-fanged, teeth. Sometinies, two oth 
teeth, which soon fall out, lie behind these, on each side c 
the upper jaw. In the mandible there are no inciBors, lnj 
a single short canine is followed by three, similar, eimpl 
teeth, and by one other, which is caducous. 

The dental formula is therefore i. ^-r^ c. ~^ p.m.n 
+ ^ - 2i. 

3, The FhomdfB, or ordinary Seals. — The pinna i 
gether absent. The hind limbs are permanently stretc 
out, pai'allel with the tail ; and, consequently, they aj 
to support the body, or asBist in locomotion on land. | 

The space between the orbits is extremely narrow, ana 
aupra-orbital processes are absent. The hulla tympani is 
very large and thick-wiUled ; and the middle, aje muc^ 
shorter than the outer, digits of the pes. | 

The common Seal (Phoca vUul'ma) is a native and acoea* 
sible member of this group. It has a iMunded head an^ 
a neck which is well mai'ked, though shorter in proportion; 
than that of the Eai-ed-aeals. The nasal apertures a 



THE PHOCID^. 4li5 

like and cam be closed at Trill, the eyea large and biil^- 
liiuit, and Hie auditory HpertiireB smaJl and devuid of a 
piuna. Tlie limbs are large, and their distal, lunger than 
their pTOximal, diTiaions. The fore limh ia buried bejond 
the elbow in the common integument, but the fleiibla- 
wriat aBowa the weight of the body to be supported by the. 
palmar surface of the monua. The hind limbs, on tha 
contrary, are permanently extended and turned backward*/ 
parallel with the tail, which lies between them, and with 
which they form a sort of terminal flu. When the Seal 
swims, in fact, the fore limba are applied against the sides 
of the thorns, and the hinder moiety of the body being 
very flexible, the conjoined hind limbs and tail are put to 
the Bume uae aa the caudal fln of a Cetacean. The Seal hae 
twenty doi"80-lunibar vertebne, of which five are lumbar. 
There are four aacral yertebra), but only one of these unites 
with the ilia. Eleven vertebite enter into the formation of 
the short tail. There are ten true riba and nine stemebrs^ 
the manubrium being prolonged forwards into a long carti- ■ 
laginoue process. 

The brain-case is emooth, rounded, and spacious, bnt 
ttie cranium narrows rapidly in the interorbital region. 
Its floor ia remai'kably flattened from above downwards and 
very thin, the broad baai -occipital sometimes presenting a 
jerforation in the dry skull. The falx is partially, and 
■the tentorium is wholly, ossified. The occipital aegment 
'ia very large, and the supra^oceipit«l advances between 
'the parietals, but does not separate them completely. The 
jalisphtaioida are small and almost horizontal, and the syn- 
'iBhondroaia between the basiapbenoid and preephenoid 
{persists. In all these respects the Seal's skull is strikingly 
cetacean. In fact, if the supra-orbital processes were sawn 
loff, a Porpoise's brain-case would closely reaemble a Seal's. 
Sut the nasal bonea and the parietala are large, and the 
lethmoidal region ia very peculiar. The lamina perpen- 
^dtoularis is largely ossified, and the vomer soon becomes 
weified into one mass with it. The two ethmoidal tur- 
^mala (or the supei-ior and middle) are small imd flati 



* 




426 THE ANATOMY OF YEBTEBEATED ANZMAXS. 



and the latter antyloBeH -with the vomer on each. aide. 
The inferior, or maiillaiy, turbinal ia eitremely large and 
compliciited, and it blocks tlie naeal paesaga in front of tbe 
othera like a sieve, or etrainei'. TLere is no lachrymal 
bone, hut the jugal ia large. The Bquamoeal is antyloa 
with the periotic and tympanic. The latter ia massive a: 
shell-ehaped, somewhat as in the Cetacea, hot it has rather 
different relations to the auditory meatus. The periotic 
ia very large, and its tnmid pars maatoidea app»;ara largely 
on the eiterior of the skull. The fossa under the superior 
vertical semicircular canal ia prolonged into thia tumid 
part of the periotic. 

The alveolar portions of the premaiillffi are very smiill, 
hut theae bonea extend far up the sidea of the ajiteriw 
nares. The maxillte do not extend over the frontala. 1 
mandible has a weU-developod coronoid proceas. 

The polleic is the longest and strongest digit, the oUien 
gradually decreasing in length. The fifth metacarpal arti- 
uulates with the cnneiform bone, aa well ua with the unoi- 

The iliBm ia short, and the long pubis and ischium are 
greatly inclined backwards, bo that the long diameter of 
the OS innominatiint makes only an acute angle with the 
spine. The femur ia much shorter than the humeros. 
The tibia and fibula are ankylosed, and more than twice aa 
long as the femur. The pea ia longer than the tibia. The 
astragalus baa a peculiar, roof-shaped, tibial surface, and 
sends a proceas backwards which contributes to the forma- 
tion of the very short heel. The halhis is the strongest 
of the digits ; while thia and the fifth digit are the longest 
of those of the pes. 

The cutaneous mnscle ia largely developed and inserted 
into the humerus. The pectoralis major is very large, and 
arises from each side of the prolonged manubrium, and 
even in front of it, beneath the neck; the fibres of the 
muscles of opposite sides are continuous. The patmarit 
longits is a strong muscle, but the proper digital muscles are 
weak or absent, as in the case of the abductor, addaelor. 



THE PHOCiDffi. 427 

fiexor hrmris, and opponent of the fifth digit. A Bpeeial long I 
abductor of this digit, however, paasea from the olecranon to T 
the distal phalanx. The iliacKS ia wanting, and there is ; 
psoas major; hut muscles which represent the psoas min 
and the aubvertehral muacles of the Cetacea are Tcry large ] 
and play an important part in effecting the locomotion of the 
Seal. The peciineve is very small, and the other adductors 
are inserted, not into the femur, hut into the tibia. The 
ghdreue maximng is inaerted into the whole length, of the 
femur. The aemumembraiioBKii and aemi-iendinotus ar 
placed by a fa'odo-tibialis, which arises from the anterior ■ 
caudal vertebr» and is inserted into the tibia, some of ita I 
tendinona fibres extending to the plantar aspect of the 
hallux. The poplibcUB and 0astroc'nemhia are strong, bnt 
there ia no solceus. The tendon of theplantarit passes o 
the calcaneum and ends on the plantar fascia of the per- 
forated tendon of the fourth digit. The other perforated 
tendons seem to arise from the fascia attaahed to the ca^Jl 



The dental formula is i. ^—^ e. j^ m.p.m. ^^ = 34, 

The grinding teeth have triangular crowns with notched 
edges, and at most two fangs. 

The millc teeth are shed during fcetal life, and at this 
period thei'e are three molars above and below on each sid^ I 
i*hich appear to be replaced by the second, third, andifl 
fourth of the adult set. If such be the case, only the hinder-J 
moat of these last will be a true molar. 

The tongue is bifid at the eitreniity. The casophagufi, 
> Tery wide and dilatable, passes without any very well 
marked line of demarcation into the stomach, which is ' 
a great pyriform sac with its pyloric end bent upon itself. 
The intestine ia about twelve times as long as the body. 
The colon is short, and is provided with a ciEGnm. The liver 
is divided into a great number of lobules, which are, as it 
.-were, set iipon the inferior cava. Thelatter vessel, just bi 

! diaphr^m, presents a great dilatation, into wl 
e itepaticiB of the several lobules open. After 



428 THE ANATOMY OF VEKTEBEATED ANIMAI.a. ' 

veramg the diaphragm, the vena cava ia Burrounded, tor 
about ttu inch, by a layer of red circular miiaculaj- fibres. 
The aorta and the pulmonary artery are both dilated at 
their ooniinenccments. 

The penia of the male ia contained within a prepuce, 
supported by a loop of the cutaneons muscle. There is a 
large oa penis, which preaenta a (ffooTe for the urethra 
inferiorly. The prostate is small, and tliere are no vesicula 
or Cowper'a glands. The testes lie juat outside the inguinal 
canal. The anua and the vulva of the female are surrounded 
by a common fold of integument. The clitoris taa i 
bono. The body of the uterus is divided by & longitudinal 

n. The Proboscidea.— These are massive finima l s , waltiDg 
upon the extremities of the five toea, with which ea^h font 
is pi'ovided, and upon a great tegomentary euahion which 
unites these, and forms a flat sole behind them. 

The nose is prolonged into a flexible proboscis, which ia 
at once a strong, and a debcate. organ of prehension. The 
hairy covering is scanty in the recent species ; but there 
was abundant long hair, and an undercoat of wool, in at 
least one estinct Proboscidean, the Mammoth {ElephoK ffri- 
wAgeniaa), which ranged over Northern Europe and Asia 
duiing the glacial epoch. The pinna of the ear ia laige 
and flat. The testes of the male remain in the abdomen, and 
the mam m in of the female are placed between the fore 

The dorso-lumbar vei-tebne amotmt to as many ax twenty- 
three, and not more than three of these are lumbar, so that 
the doi^al region ia, proportionally, exceedingly long. There 
are four sacral vertebne, followed by a comparatively short 
taiL The centra of the vertebne are far more flattened, 
from before backwards, than those of any other terrestrial 
mammal, and this is particularly the case in the cervical 
region, whence it follows that the neck is extremely short. 

The skull is enormous, even in proportion to the body, 
its size arising, in great measure, from the development of 
air cavities in the diploe. The interspace betweea tlte , 



430 THE ANATOMY OB VEKTEBEATED AN1MAI.S. 

iimer and tlie onter tables of the skull ia often, in an old 
elephant, considerably greater than the diameter of tlie 
cerebral cavity itself. The cranial cavity ia elongated and 
BubcyUiidrical, The aapra-occipital rises far upon the roof 
of the skull, so tliat the parietals are much, narrower at 
the sagittal suture than elsewhere. The preutajdUae are 
very large, and the nasal hones short, the iiaaal pasBU^ 
being neaj'ly vertical. The jugal bone forms only the 
middle part of the jngal ai'cade. The rami of the maaidible 
have a high perpendicular portion, and they are largely 
ankytosed at the symphysis, which is prodnoed into a eort 
of Bpoul. 

The acromion of the scapula has a reenrred process, 
Bucli OS is frequently found in the Bodenta, to which order 
the Proioscidea present many curious approximations. 
Thei'e are no clavicles. In tho autebraohium, the radius 
is permanently fixed (though not ankylosed) in the prone 
position, crossing the ulna obliquely. The carpal and 
metacarpal bones, imd the phalanges, are remarkable for 
their short and thick form, and the manua is larger than 
the pes. 

The ilia are immensely expanded ti-ansversely. The 
femur, which is not connected by any round ligament to 
the acetabulum, ia relatively long and slender ; and, when 
the animal is at rest, is dii-eoted perpendicularly to the 
axis of the trunk, not bent up, so as to form an acute angle 
with that axis, as it is in ordinary quadrupeds. The ham 
consequently occupies the middle of the length of the hind 
leg ; the flexion of which, at this point, when the n-ni'mal 
walks, gives an elephant a gait which is strikingly dif- 
ferent from that of other quadrupeds. The tibia is reb- 
tively short. The fibula is distinct and complete, and the 
bones of the pes have the same broad and short form bb 
thoie of the mauus. The hullux has only a single phalanx 
in some species. 

The Proboseidea have only two kinds of teeth, incisora 
and molars, canines being entirely absent. The incisors 
aio composed of dentine and cement, with or without a- 




THE PKOBOSCIDEA. 431 

■longitudinal belt of enamel, and. in the recent Eleplinnta, 

s developed only in the upper jaw. Ah their growth 

wntinues for a long period, or thronghout life, they 

aBnully take the form of long tuaks, which project on each 

Bide of the upper jaw. The molar teeth are composed of 

f dentine, enamel, and cement, and their crowns, when nn- 

1, are always ridged, the ridges very often being made J 
np of distinct tubercles. The intervals between the ridgefrl 
are sometimes, ae in the Asiatic ^Elephant, exceedingly dee|V ■ 
narrow, and completely filled np with cement ; or, as iiCl 
the African Elephant, they may be ehallow and open, thoi ■ 
cement forming only a thin coat. In the recent Elephantdj ■ 
only the two incisorR are preceded by milk teeth. Thflffl 
molars are, altogether, six on each side, above and belowjirj 
they come into place and use HuccesBively, the hinder onesja 
moving forward, in proportion as the anterior ones airft.1 
worn down by the attrition of those which are opposed to. ■ 

The etonmch is simple and elongated, and there is a rei^t ■ 
wide ccBcum, The trilobed liver has no gall bladder. Th» J 
heart has two anterior cavte. 9 

The cerebellum is left uncovered by the cerebral hemi< M 
spheres; which, in the existing Elephants are large, andi:l 
have greatly convoluted surfaces. ■ 

The male reproductive organs eihihit two very largjS 
vesicule eeminaies, and four pi-oatates. The uterus of thjfl 
female has two cornua. H 

Some, if not all, species of the extinct genus Mantodot^^ 
were provided with a pair of short tusks in the man^H 
dible, in addition to the large ones in the premaxills. AsdH 
in some of these animals, as in certain other extinct EI»^ 
phants. the anterior grinding teeth had vertical suceeasora. 
The Miocene genus. Dinotheriatu, possessed two large, down- 
wardly-directed, tusks, one on each side of the symphysis 
I of the mandible, while there were none in the upper jaw. 
L^e second and the third anterior gi-inding teeth hadji 
■Vei'tical successors. ^H 

L The Probosoidea are, ai present, restricted to Asia aj^^| 



[ 



433 THE ANATOMY OF VEKTEBBATED J 

Afi-iea. mliei-e they ore repreaenteil by two very diatinoj 
forms, to which the names of Loitodon {E. africanm} rmj 
Eaekphas (E. ind'tmu) proposed by the iiite Dr. ralcon^ 
may he very properly applied. The oldest rocks in whioS 
their remains occur are ot Miocene age. Fossfl remains (i 
elephants occur not only in the old world, but also in botl 
North and Sonth America. j 

III. The Hyraatidea. — The genus Hyraie, Trhicli is tld 
sole member of this group, was referred by Pallas to tu 
Rodents; and by Cuyier, who demonstrated that it could 
not be a Rodent, it was placed among the Ungulaia, in thi 
immediate neighbourhood of Shinoceroa. without any bettd 
evidence than that afibrded by the oharactere of the moUJ 
teeth. Prof eaaor Brandt of St. Peterabiu-g, in an elabcrati 
memoir just published, arrirea at the conclnsion that it i| 
a " ghriform "Ungulate," intermediat*, in a certain sensa 
between the Rodemia and the Ungvloia; but, still, moti 
Ungulate than Rodent. It appears to me to be neithq 
Ungulate nor Rodent, but the type of a distinct order, il 
many respects intermediate between the TJngidata, on tbd 
one hand, and the Bodeatia and Imectivora, on the other. J 

The small, Rabbit-lite, animals comprised in the genni 
Syrax are plantigi-ade, and provided with four visible U>et 
in front and three behind. The nails are not hoof-lik« 
bnt nearly flat, eicept the innermost of the hind foot, whicB 
is peculiarly curved. The body is covered with far, aiti 
the mViffle, or snout, is split, as in the Rodents, There il 
a pendulous penis, but no scrotum; and there are fcnill 
inguinal and two axillary teats. j 

There are from twenty-nine to thirty-one dorso-Inmlna 
yertebi-ffi, which is the greatest number known in any teia 
restrial mammal. Twenty-one or twenty-two of thew 
are dorsal. No mammal, escept Chol<epiis. the two-toed 
Sloth, pnasesaes ao large a number of dorsal vertebrte ad 
this. The transverse processes of the last lumbar vertebra 
articulate with the saerum, as is the case in many Ungulats 
Mammals. In the skull, the post-orbital proeesses, which ari 
chiefly furnished by the parietal and the jugal, nearly meeti 



THE HYK4C0IDEA, i33 

Part of thfi articular facet for the mandible ie formed by 
the jugal, which extends forwarda tmtO it comes into 
contact with the lachrymal bone. The base of the external 
pterygoid process ia perforated by a canal, as in Perisao- 
dactyla and LetnMHdce. There are large pre- and post- 
tympanic processes, and the post-tympanic is much Bhorter 
than the par-occipital process. The premaxillfe are large, 
and nnite extensirely with the nasal bones; the perpen- 
dicular ramus of the mandible is very wide, and somewhat 
lite that of the Tapir in shape. The posterior margin of 
the bony palate is opposite the anterior edge of the last J 
molar tooth. 1 

The scapula is devoid of an a<?romion process, as in the ' 
Ferissodactyla. There are no claricles, but the coracoid 
proeeBB is well deTcloped. The ulna is complete, and a 
mdiment of the pollex is present. In the carpus, a line 
prolonging the aiia of the third metacarpal bisects the oa 
viagiiam, and the huuiTe, which is not the case in any 
Ungalate Mammal. I 

In the hind limb, the femur poaseBseB a ""pll third tro- ■ 
chanter, which is not nearly so conspicuous as in some 
Rodents. The tibia and fibula are complete. The ex- 
tremity of the inner malleolus articulates with a shelf-like 
process of the astragalus, the distal face of which bone has 
on facet for the cuboid. The digits i. and v. are not repro»J 
aented even by rudiments. The terminal phalanx of ii. i(fl 
longitudinally cleft. I 

The dentition of the adult is i. —^ c. ^^ p.m. j-r^, ana^ 
m. j7^. The outtr uppei- incisors are very small, and soon j 
fall out; the inner, which are very large, curved, and have 
a thick coat of enamel on their anterior faces, continue to 
grow throughout life, as in RodentB. The lower inciaora 
have crowns denticulated at the edges, like those of Galeo- 
jiithecua and some Bats. They bite upon a calloua pad 
which lies behind the tipper incisors. The pattei'UH of the 
upper and lower molar teeth are very similar to those ot I 
the corresponding teeth In £hiaoeeros. As in the HoraOrJ 



1 



434- THE ANATOMY OP VEETEBEATED ANIMALS. 

part of tho Eustachian tube ia dilated into a, thiu-wallrf 
sac extending on the inner aide ot the bulla tympani from 
the pterygoid proeesBeB to the exit of the ninth nerve. 

A alight constriction marks off tho cardiac from tt* 
pyloric diviaion of the Btomach. The cardiac portion 
lined by a denae epithelium. The intestine ia provided w 
three eoaca. — one in tho ordinary position, and two placed 
much lower down on the colon, opposite one a.iiotl»er, and 
terminating by pointed ends. There ia no gall-bladder. 
The ureters open, not near the neck of the bladder ai 
Mam mala generally, bat near the fondue, aa in some few 
Rodents. 

The male haa ve^ailw seminales, pi-ostatic and Cowperian 
glands. The uterus is two-homed, and the vnlya and a 
are surrounded by a common fold of integument. 

In the tfEtuB the yelk aac and the vitello -intestinal dnct 
early disappear. The amnion is not vascidar. The allantois 
spreads over the interior of the chorion, and gives rise hi 
the broad zone-like placenta, which ia composed of both 
maternal and fratal parts. The maternal veasela puss 
straight through the thickness of the placenta towai-da ita 
ftEtoi Burface, on which they anastomose, forming meshes. 
through which the veaeela of the ftetus paaa towards the 
uterine surface of the placenta. 

The species of the genua Syrax are found only in Syria 
and Africa. No foaail Syracoidsa are known. 

The DisooiBBA.^The Mammalia with discoidal placenta 
are the Bodentia, the Cheiroptera, the Insedivora, and the 
Pi'uiMites. 

1. The RODEMTIA.— Tliia large gi-oup of MammaJia is 
most definitely characterized by Jte dentition. There are 
no canines, and the mandible never contains more than 
two inciaora, which are placed one on each side of the 
aymphysis, and continue to gi'Ow throughout life. They 
are coated with enamel much more thickly upon their front 
surfaces than elsewhere ; ao that by attrition they acquire 
and retain a chisel-Bhaped edge, the enamel in front wearing 
away leas rapidly than the rest of tLe tooth, 



THE EODETJTIA. 435 

"With the esception of one group of BodentB, there are only 
two teeth in the premaxilliQ ; and theee have the same cha- 
racters aa the incisors of the mandihle. The Lagomorpha, o 
Harea and Rabbita, however, have a eecond pair of incisor 
of amall size, behind the first, in the upper jaw. The niohiTS' | 
are from two to eii in nnmber, in each ji a l f of the upper 
jaw, and two to five, in the lower jaw. They consiBt of 
enamel, dentine, and cement, and their crowns may be 
tubereulate or laminate in pattern. Sometimes they form 
roots, but, in other cases, they grow thronghout life. 
Where there are more than three grinding teeth, the 
one which precedes the three hindermost has displaced a 
milk tooth; but where the grinding teeth are fewei" than 
tbi-ee, or only three, none of them displaces a "lilk tooth. 
Even when milk teeth esiat they may be shed before birth, 
as in the Guinea-pig. 

The premaxiUary bones are always large, and the orbits 
are never shut off by bone from the temporal fossa. Vei^; J 
generally, the condyle of the mandible ia elongiibed froiS 
before backwards. 

With the exception of one grsup, the Dormice {Myox- ' 
ineB). all Rodents have a large caecum. 

The cerebral hemispheres leave the cerebelluni largely 
uncovered, when the brain is viewed from above. They 
are either smooth eitemally, or veiy moderately convoluted. 
The corpus callosum is well developed. 

With the exceptions noted, the foregoing characters a 
univeraal among the Rodentia. There are other peculiarir J 
ties whicli are generally present, and when they exist, n 
very characteristic, though they are not universaL 

Thus the dorso-lnmbar vertebrte ai'e usually nineteen m" 
number. There is a large interparietal ossification. The 
jugal hone ia comparatively short, and occupies only th-' 
middle of the zygomatic arch. 

The clavicles are very generally present ; though wholly 

Bbaent in some genera, as, for example, the Guinea-pig, 

{Cama). The acromion commonly sends a process back- 

It the infrurspiiKiuB fossa. There is a ninth bone 




436 THE AHATOMY OF YERTEBEATED AlflMAXS. 

in the carpue intercalated between the proiimal and til 
distal series. The digits are five, nngulate, ajid prorid«d 
with small claws. 

There is a bone in the penis. The testes do not leaye tit 
abdomen, hut come down into the ^oin in the breeding 
season. Yesicnlse seniinales and prostatic glands 
present. In the female the uterus is, in manj genera, 
completely divided into two oomua, each of which opens 
separately into the vagina; bat, in the rest, the 
unite int« a cmpus utei-i. 

Some genera depart widely from the rest in paiTtieiilDT 
points; for eiample, in the Porcupines, the haira o 
dorsal region of the body are very miich enlarged, acquire 
a peculiar structure, and form the so-called " qniUa." Some 
of the Porcupines have prehensile tails. 

In Cavia and Hydroehcertts the toes are reduced to three, 
and the nails have almost put on the character of hoofs. 

The SquiiTels have the short poUex almost opposable. 

The femur in some Bodenta has a well-developed third 
trochanter; and in Dipus, the Jerboa, the long metataraak 
become ankylosed together into a cannon bone. 

In the Porcupines, the suborbital foramen is enormous, 
and Ml anterior fasciculna of the masaeter mascle arises 
from the masilla, and traverses the foramen to its insertion. 

The Hamster (OKcedw) has great cheek pouches, pro- | 
vided with special retractor muscles connected with the 
spines of two Inmbar Tert«bne. 

In some genera, the stomach, which is usually simple, 
tends to become complex. Thus the cardiac division of 
' the stomach of the Beaver ia provided with a special glan- 
dular mass. The cardiac end of the (esophagus of the 
Dormouse is glnndiilar and dilated like the proveviictilm 
of a bird. And, in Arvieola, the stomach becomes deeply 
■ constrictfid, and a groove leads from the (Esophagus towards 
the pyloric end, reminding one of certain Artiodaetyla. 

In some few genera, the ureters open into the fundus of 
the bladder, or near it. 

Although the genera and species of the J 



THE ANATOMY 



H. more mimerouB than those of any other mammciliac orderH 
9 and although they are adapted t« very different modes o 
life — Home, like the "Plying Squirrels," floating throcgli 
the air by meana of a parachute-like eipanaion of the in- 
tegument between the fore and hind limbfl; others being 
arboreal, like the ordinary SquirrelB ; or ajnong the swiftest 
of runners, oa the Hares; or etrong burrowera, ai 
jaale-likeBathy^guB i or aquatic, like the Water- vole— 
Btructural differences are comparatively insignificant, a 
the aubdivision of the order into large groups is proportioa4fl 
ately difficult. 

Brandt has divided the Bodents according to theii 
cranial characters into Sciuromorpha, Mymaorpka, Bi/airt-1 
oomorplia, and Lagmnorpha ; or. Squirrels, Rata, PorcupineB, 
and Conies, if we use these English names in a broad and 

JThe student will find the Rabbit, one of the Lagomorpha, 
to be a conveniently sized and easUy obtained Eubjeot fo^ 
«tudy. The following are the most important p 
noted in its structure. The hairy covering of the bod^ 
extends over the palmar and plantar regions of the feet, and 
into the interior of the mouth, so that there ia a band of 
hair on the inside of each cheek. Ihere are five digits o 
the fore foot, or manua ; but the pollei is smaller than the 
othera. The pea has only four digits, and the hind li 
longer than the fore limb. The uppei- lip ia large, fle 
and cleft in the middle line; the large eyes are provide 
with a third eyelid, and tliB pinnm of the eara are v 
long and mobile. The tail is short and recurved, 
male has a recurved peuia, and on each side of it a » 
sac. The female has five pair of abdominal teata. I 
Bexes perineal glands are preaent, consisting of a 8( 
involution of the integument with rugose walls, into whi 
the duct of a special gland lodged at the aide of the p 
■ of the clitoris, opens. 

There are nineteen dorso-lumbar vertebrtD, of which ti 
■e doi-eal. Of the four sacral vertebrte only the fir»l u 
iiith the ilJA. The dorml vertebra LtiTe w«U-<kv«li 



4-38 THE ANATOMY OP VESTEBEATED ANIMALS. 

spinouB and transrerae pTocesaea. At about the eighth, a 
mammillary process, or melapophytis, becomes obriona; 
and, in the Bucoeeding vertebrie this increaaeB in length Mid 
Btrengtb, till in the lumbar region it becomes as long Bi 
the Bpinona process. In the last lumbar, it is short, and 
in the sacrum, it is obsolete, but it is traceable throngt 
the eeries of the aaterior caudal vertebra!. Aeeesaory pro- 
ceeses, or anapophyaes, are observable in the last dorsal 
.ind four or five anterior Imnbar vertehrte. The trana- 
verse processes of the lumbar vertehne are esceedingly long, 
and that of the first lumbar is bifui'cated at its extremity. 
These transverse processes give attachment above, to the 
eaero-lv/mhoMs, and below, to the psoax inajoTt both which 
maaclea are very large ; while the heads of the longismmu 
dorii are attached to the long metapophysea. The great 
mass of these extensor and flexor rauscleB of the apine, and 
the leverage afforded by the mode of their attachmeat to 
the long processes of the vertebra, would seem to be re- 
lated to the leaping and scratching movementB of the 
Rabbit. Strong median proceases are developed from the 
ventral faces of the centra of the three ajit«rior lumbar 
vertehne ; these give attachment to the cnini of the 
diaphragm. 

The tubercles of the second to the eighth ribs inclusively 
are prolonged into spiniform proceases, which give attach- 
ment to the tendons of the loTtgissimiia dorsL There are 
flvestemebna and along xiphoid prooeas. The manubrinm 
is long, narrow, deep, and keeled inferiorly. 

In the alcuU, the gi'eat supnt-orbital processes of the 
frontal are to be noted. The presphenoid is high and 
gi'eatly compressed from aide to side, so as to form a thin 
septum between the orbits, and the optic foramina run into 
one. as in some Seals. The tympanic and the periotic are 
ankylosed together, but remain distinct from the adjacent 
bones, and are merely held in position by abutting against 
the basi-sphenoid on the inner side and by the post-tym- 
panic hook of the squamosal on the outside. The tympanic 
ia prolonged upwards and outwai'ds into a tubular meatus. 



THE MTOLOaY OP THE KABBIT. 

The glenoid carity is elongated from before bactwards. 
Tlie sutare betweeu tlie jngaJ and the moiiUiuy becomea 
obliterated, imd tliere is no orbital process given off froma 
tlic zygoma. A considerable extent of the outer wall of thig 
iiiiisilla vemaina incompletely ossified. The preniiviilla ii 
i-:itreioely large and tvifurcated. 

The ascending portion of the ramus of the mandible q 
long, and the eoronoid pixicesa well developed. The lom 
axis of the condyle is antero-posterior, and the o 
pi-oceaa haa a sKght inward projection. In the palate, the™ 
prepalatine, or inciaive, foramina are enormons ; and partly 
in consequence of thia, partly by the posterior eicavation 
of the palatal plate of the palatine, the roof of the palate ia 
reduced to little more than a transverse bar of bone. 

The acapnia is long and narrow, and the backward pro 
of the acromion, to which reference has already been n 
gives attachment to a slip of the trapesias. A bony clavicli 
is present, but it is incomplete at both ends. There la a 
anpra- condyloid foramen in the humeruD. The radius and 
ulna are complete, but are fixed in the attitude of pro- 
nation. 

The femnr haa a araall third trochivnter. The tibia and 
fibula are ankylosed. The internal cuneiform bone ia 
•(ranting, and the plantar surface of the navic-tilare givca off 
a large process. The inner side of the base of the second 
metatarsal sends a process along the inner face of the meso- 
caneiform to articulate with the naviculare. Thia may 
jcpresent a rudiment of the hallux with the ento-cuneiform. 

In the myology of the Riibbit tbe vast size of the flesora 
and extensors of the buck haa already been noted. The 
■muaeles moving the fore, and especially the hind, limbs, 
and the ntaegeter, are not less remarkable for their dimen- 
In the fore limb, the supinator longus ia absent. The 
wieleniwittdieu and aecundiinteraodiipoUicit form one muscle, 
^lecintefwwrnwnwmdij^goea to the fourth and fifth digits. 

le flexor perforana and the flexor potlicia iowj/tw unite in 

:ommon tendon which divides into five alips, one for each 
Tliwe ar« ihxea lumbricale« from the radial sides 



440 THE A.NATOMY OF TEBTEBKATED ANIUAIiS. 

of the tendona for tlie third, fourth, and fifth digits. "Be 
jlBxor eablimU. or perfaratue, for digits it., Hi., and iv. ariee! 
from the inner condyle aa QHual; but that for the fifth digit 
spiTngB from the piaiform bone — thus sinmlating the o 
dinarf arrangement of the perforated flexor in the pes. 
There is no pronator qvadratug; but the palntarU loagvi 
ia distinct, and its slender tendon expands into the pahnar I 
aponenroaia. Bach digit, except the poUes, has a, pair of I 
jlescores breves, or inleToasei, which lie on the palmar faces of 
the metacarpal bones. 

In the hind limb, the gofeiM has only a fibular origin. The 
ptantaris is very large and ensheatbed in the gaatrovnetrwitt ; 
it ende in a tendon nearly as large as the iendo AekiUi*, 
which passes over the end of the calcaneum, being con- 
nected with this and the tendo AohillU by a strong fascii 
laterally, but being, otherwise, eeparated fi-om it by a 
synovial sac. In the sole of the foot it divides into four 
tendons, which become the perforated tendons of the 
four digits. The flexor perforans and flexor hallncis an 
fused into one muscle, the tendon of which divides in 
the sole into the four perforating tendons. There are 
three lumbrieales. and four pair of inleroMei (Jlexoret brefMu). 
There is no proper tibialis postlcna, but a muscle arises 
from the upper part of the inner face of the tibia, internal 
to, and in front of, the insei-tion of the poplil(EU«, becomes 
tendinous about the middle of the leg, passes behind the 
inner malleolus, and runs along the inner and dorsal aspect 
of the second metatarsal to be inserted into the extensor 
tendons. It eeems to stand in the same relation to the 
second digit as the peromsiu qmnti, on the opposite side of 
the pes, to the fifth digit. The peronmv^ langua is inserted 
into the base of the second metatarsal : a perojuBtu brtmit, 
p. guarti, and p. quinti digiU are present. There is no 
exleritor hallucU longiu, nor any escl-ensor brevis digiicynmn. 

The principal characters of the brain of the Babbit have 
already been described (see p. 64, and Figs. 21 and 22). 
There is a single large corpus mammillare. Of the corpora 
jfWHlHj|«nMma, the nates are larger than the testes. There 



THE DENTITION OF THE B&BBIT. 441 J 

ia a, very large and completely espoaed flooculus. and tha ] 
vermis ia large in proportion to the lateral lobca of the i 
cerebellum. The corpora trapasoidea are well marked. 

Tbe nMmibrana nictitans ie very large, has a convex free i 
edge, and containa a triajignlar cartilage. There ore no ] 
jmncta lachryTnalia, but a croaeentic aperture leads into the J 
lachrymal canal. The large lachrymal gland lies above and'T 
external to the eyeball, and there ia a well-developed I 
Hordeiian gland on its lower and inner side. 

Tkc dental formula, ia t. ^ c ^ p.m.. ^^ m- ^ = 28. 

The lower, and the inner upper, inciaors are veiy large and 
long; they growcontinnouHlyfromperaistentpulpB, and they 
are coated with enamel only in front, ho that wear keepa 
them constantly sharp. The second pair of small incisors 
esiats only in the upper jaw, A great diastema separates 
the incisors from the first premolar above and below. Tha 
grinding teetli all grow from peraiatent pulps, and do 
form fanga; they have tranaverBely ridged crowns, 
patterns of which axe very aimilar throughout, the first 
the laat only presenting some differences. The yoi 
Kabbit has three incisors and tliree milk molars 
side, in. the upper jaw. In the lower jaw, there are onlj 
two milk molars on each aide. 

The stomach is simple, and there is a large 
Special glands pour their secretiona at the side of the anus. 

The piuicreae is very large, and its duct enters the ia- 
testine nearly a foot from the pylorus, and far diatant 
from the biliary duct. 

There ore two anterior cavie ; and the estemal jugular veia 
is very much larger than the internal. 

In tbe male, the inguinal canal remains permanently 
open, and there ia a large uterus masctdinna. In the female, 
the uteri are quite separate, and each opens by a distinct 
OS tinoB into the vagina. 

The distribution of the RodeTitia is almost world-wide, 
Madagascar being the only considerable ialond in which 
indigenous Rodents are imknown. The AaBtro-Ccdnm* 



1 




442 THE ANATOMY or VERTEBKATKD ANIMALS. 

bian province may 1je regarded 0.3 the headquarters of ihe 
group. 

Remains of Rodents huve been found, in the fosBii state, 
as tar back as the eocene formation. 

IL The iNaBCTiVORA, — It is eseeedingly difficult to gm 
an abaohite definition of this group of mammals. But idl 
the Inaeotivora possess more than two incisors in the man- 
dible ; and their molar teeth, whioh are always coated witb 
enamel, have tuberculated crowns, and form roots. 

The fore limhs haTG the structure nsoal among nngni- 
culate mammals ; and, in both limbs, the digits are proyided 
with claws. The hallux is not opposable, and, like the 
other digits, it ia provided with a claw. 

In addition to these distinctive characters there are 
others which are met with in all members of the group. 

The Insectivora are, almost all, either plantigrade or semi- 
plantigrade. The clavicles are completely developed in all. 
oicept Potamogah. The stomach is simple. The testes 
of the male are either inguinal or abdominal, and do not 
descend iato a scrotum. The female has a two-horned 
uterus. 

The cerebral hemispheres leave the cerehellum unoovered. 
in the npper view of the brain ; and are almost, or wholly, 
devoid of sulci and gjTi. The corpus cuLosum is somedmes 
exceedingly short. 

No Insectivore attains a large size, and some, such as the 
Shrew Mice, are the smallest of the Mammalia. 

The Insectivora present a great diversity of organization, 
the common Hedgehog being an almost central form. The 
Shrews tend towards the Bodentia, the 'Pupayne towards 
the Lemurs ; while the Moles, on the one band, and the 
Qaleopitheci on the other, are aberrant modifications. Re- 
lations of a more general character connect them with the 
Camivora and the Ungvlaia. 

The Hedgehog (Erinaeeug Ewroptsug) is pentadactyle and 
plantigrade. It has a long flexible snout. The eyea are 
small ; the pinnsa of the ears are rounded, and the integ^- 

jnt lining the concha is produced into a, 



THE ANATOMY OF THE HEDOEHOG. 



443* 



■, fold. The under aui-face of the body bears bairs of 
e ordiuiirj kind; but, on the dorsal aapect of the bead 
md trunk, the hairs ai'e conyei'tcd into strong fluted apineai 
;'e twenty-one dorao-lumbar Tertebrse (of wbioll 
'e doreal, and six lombar), three or fonr sacral, and; 
fwelve to fonrteen caudal. Accessory prOEeaaea, or meta* 
pophysea, are developed on. sereral of the dorso-lumbar vex*r 
tebr». The stemebne are laterally compressed, except the^ 
manubrmm, which is broad ; and eight of the fifteen pair of 
ribs are connected with the sternum. 

The ocoipital foramen is placed completely at the hindi 
eitremity of the skull, in the lower part of the perpen- 
dicular occipital face of the cranium, and looks baekwards,. 
There are large paramastoid processes. The glenoidal 
surface for the mandible ia flattened. The zygoma is stout, 
and the jugal bone ia, as it were, applied upon the outer 
side of it. The orbit has no posterior osseous boundary. 
The lachrymal foramen lies upon the face. There are 
unoasified spacea in the bony palate, and the posterior 
margins of the palate ore thickened, ae in the Lemurs. 
The large and bullate tympanic bone does not ankylose 
with the Bquamoaal, or the periotic, and ia readily lost from 
the dry aknlL The alisphenoid contributes largely to th& 
formation of the front wall of the tympanum; and a large 
portion of the inner wall of the tympanic cavity ia formed 
by a broad process of the baaisphenoid, the outer and lower 
edge of which joias, by a sort of harmonia, with the inner 
and lower edge of the tympanic. 

The ascending portion of the ramus of the mandible is 
short, and the angle is alig-htly inflected. The two 
are not ankjlosed at the symphysis. The supra-acapuli 
foaaa ia wider than the infnt- scapular. The spine is atrong, 
and the acromion bifurcates, sending a prolongation " 
wai-ds. The claviclea are long and convex forwards. 
humeruB haa an intercondyloid foramen; but there 
foramen above the inner condyle, and this circnmstanco 
ia unusual among the Ineectivora. The bonea of the anti- 
'6 fixed in the prone poeibion, Tbsre ia au «* 



lacktj^^^l 
Thd^^l 
isno^^^P 



44-t THE ANATOMY OF VEETKBEATED AKIMAJLS. 



1 tlie carpus, bo that it has nine bones. The 
scaphoid and lumLre are ankjlosed, as in the Camivora. laA 
the pisiform bune is uiiich elongated. The jtollei: and tie 
fifth digit are the ahorteat. 

The pelria ia remarkably spacious. The ajmpLysisI 
nniim of the puhea is always smali, and, sometimea, tlie 
hones remain aepai-ate. The auhpuhic arch is much roundei 
The ilium ia narrow, and a mere ridge separates the iliM 
foBsa from the gluteal surface. The femur has a roonJ 
ligament, aud a pivjminent ridge represents a third tro- 
ohanter. The distal ends of the tibia and fibula are aobj- 
losed together. 

One of the most notable peonliaritiea of the ETedgebo; 
is ita power of rolling itself np into a ball, from all sides d 
which the spines protrade. This is efiected, for the most 
part, by the contraction of the greatly developed cutaneooi 
mnacle, the ohief fibres of which are disposed as follows. A 
Terj broad band, the orbicularia pannicuU, encircles the body 
lateraUj, In front, it, partly, arisea from the nasal and 
frontal bones, and, partly, is the continuation of a thick 
mass of fibres which pasa over the occiput. Posteriorly, 
each lateral division of the muscle spreads out into a veiy 
broad band, which ia thick ventrallj and thin dorsaUy, and 
adheres closely to the skin, from the line at which the hairy 
and spinigerons sorfacea join, to near the median line "J 
the back. Posteriorly, the two lateral halves of the orbt- 
cular muscle pass into one another upon the distal hu lf of 
the short tail. 

The action of this muscle will depend upon the attitude 
of the gnimnl when it contracts. If the head and tail are 
fully extended, the orbieularig can only diminish the dimen- 
Biona of the spinigerons region of the skin and erect the 
spines. But if the head and tail he more or less flexed, as 
they always are in the ordinary attitude of the Hedgehog, 
the orbicalarU will play the part of a powerful sphincter, 
approximating the edges of the spinigeroua area towards 
the centre of the ventral side of the body, and forcibly 
enfolding the trunk and limbs within the bog Uuu ittaued. 



THE MTOLOGT OF THE HEDGEOG. 445 I 

It is, in fact, the ctiaf agent in coiling the body up, and 
keeping it so coiled. 

Numerous uiuscnlar hnndlea take a radiating direction I 
in the dorsal aspect of the body, and antagonize the orbi- I 
cularis: 1, A pair of slender occipf(o/rtmiaieg arise from the I 
occipital Great, and are ineerted into the integnment over I 
the frontal and naaal bocee. 2. A pair of oceipUo-orbicvlarei I 
arise from the same crest, and pass into the anterior part I 
of the orbicularie. 3. A pair of broader cervico-orbievlaret I 
ajise from the fascia of the neck, and pasa to the dorsal I 
pai-t of the anterior fourth of the orhicalaria. 4. Slender I 
dorso-orbicalares arise close to the hinder ends of the tra- 1 
peaii and spread out above the foregoing. 5. Two stout ] 
muscles, eoceygeo-orbiculares, arise from the middle caudal I 
vertebrtB, and after receiving fibi-es from the ventral region, J 
end in the dorsal mai^ins of the orbicalaria. S. Two ] 
mustles attached to the pinnce of the ears {auricTilo-orbicK- I 
lareK) pasa backwards to the orbicalaTis on each side. 1 

On the ventral aspect are ceitain mnscles which assist 1 
the (irHeidaris; 1. Two broad nmscloB {atemo-fadalet) arise | 
in the middle line, over the anterior part of the sternum, j 
and pass outwards and forwards to the sides of the lower 1 
jaw and the integument of the face and ears. Muscular I 
shps fi"om these are sent iip over each shoulder to the 1 
orbicularis. 9. A hwmero-ahdo'minaliB ariaes from eacli J 
hiimeruB beneath the insertion of the peetoralis major, and, ] 
passing backwards over the sides of the abdomen, these 
become connected with the ventral edges of the orbiculwria. 
The estemal fibres of these muscles are continued round the 
ischial region to the coccygeo-orbicnlaHs; the internal fibres 
pass to the prepuce, and over the middle line of the ab- 
domen, in front of it. 3. A hutnero-dorgaliB arises from the 
humerus close to the foregoing, and passing upwards and 
backwards through the axilla, spreads out in the mid- 
dorsal integument and the orMcuJaris. 

The contraction of all these muscles must tend to bring -- 
together the edgM of the integumentary bag, and to tude I 
the head, tail, amd limbs into it. J 



In the myology of tlie limbs the following pointa an 
Gotewortbj: Tbe gapinator l(mga$, pronator teres andpct 
maris longia are absent. Tbe pahnaris brevig ia preeeat i. 
single muscle takes the pla.ce of the escteitaor secundi iniemcia 
pollicis and extensor indide, and senda a third t«ndon to Ike 
middle digit. The extenaor mmimi digiM supplies the otba 
two digits. Thefiexorperforans ajiijleteor polXieie lowjut nn 
represented by fi^e distinct muscular heads, each with a 
tfindon of its own ; but all the tendons unite in the niiddlt 
of the forearm, and the common tendon again subdivides 
into only four Blips, the pollex receiving no tendon. There 
are no hiinhricaUs. The polles has only a mdiiuentary_^f«r 
hreine and an abiiictor. The other digits have each two 
imferoagai, or jlexoret ireveg, inserted into the metacarpo- 
phalangeal BesamoidH. 

In tbe leg, the soleue has only a fibular head, and tie 
flexor brevis digitorwm arises wholly fi-om the caJeaneoni. 
The fiexor halhicia and flexor perforata have a. common 
tendon, wiich, in the sole, diyides into five tendons, one fM- 
each digit. Thei'e ar eno himbricalea, nor flexor acceseoruu. 
The iibialis poeticvs seems to he represented by two small 
muaeular bellies, one of which arises from the prominent 
end of the tibia, and the other from that of the fibula. The 
tendons of both pass behind the inner malleolus, and that 
of the former muscle goes to the tibial and plantar surface of 
the hallucal metatarsal, while the latter ia inserted into tbe 
ento-cuneiform bone. The iaterosaei pedis are represented 
by a pair oifiexores breves for each digit except the Iml lnT. 

The aiiult Hedgehog has thirty-six teeth, of which twenty 
are in the upper, and sixteen in tbe lower jaw. The dent^ 
formula is i. — c. — — p.m. ^-^ m. — = 36. 

The grinding sui-f ace of the crowns of the first and eeoond 
upper molars eihihita a pattern fundamentiiUy similar to 
that of the con-esiiunding t«eth in Man, the Anlhropo- 
imtrpka, and] the minority of the Lemurs ; that is to say, 
thei'e are four cusps, and tbe antei'o-internal is coimected 
with the postero-estomal cusp by an oblique ridge, He 



THE BBAIN OF THE HEDGEHOG. 447 

cusps are remarkably sharp and pointed, and the outer sur- 
face of the postero-extemal one alone is somewhat inflected. 

In the lower jaw, the corresponding molars are each 
marked, as in most Lemurs, by two transverse ridges. In 
front of the anterior ridge is a basal prolongation of the 
tooth, on to which a cui'ved ridge is continued inwards and 
f orwai'ds from the anterior principal ridge, giving rise to 
an imperfect crescent with its convexity outwards. 

According* to Rousseau there are twenty -four milk teeth, 

*• 4:^ ^•^' iTi* which fall out seven weeks after birth. 

The brain of the Hedgehog is remarkable for its low 
organization. The oKactory lobes are singulai'ly large, and 
are wholly uncovered by the cerebral hemispheres ; which, on 
the other hand, do not extend back sufficiently far to hide 
any part of the cerebellum. Indeed they hardly cover the 
corpora quadrigemina. Only a single shallow longitudinal 
sulcus marks the upper and outer surface of each hemisphere. 
On the under surface, a rounded elevation corresponds 
with the base of each corpus striatum. Behind this, another 
elevation represents the end of the uncinate gyrus and the 
termination of the hippocampus major; and therefore 
answers, in a manner, to the temporal lobe. The inner face 
of the hemisphere presents neither convolution nor sulcus, 
except behind and below, where a very broad depression fol- 
lows the contour of the fissure of Bichat and the fornix, and 
represents the dentate sulcus. Above, this sulcus ends be- 
hind the posterior margin of the corpus callosum. The 
latter is remarkably short, and directed obliquely backwards 
and upwards. It has no genu, and the pre-commissural fibres 
of the ventricular wall spread out, beneath its anterior 
end, upon the face of the hemisphere. The part of the 
corpus callosum which answers to the lyra is very thick in 
proportion, and is inclined at an acute angle to the rest. 

In a transverse section, the corpus callosum is seen to be 
very thin, and to curve upwards and outwards into the 
roof of the ventricular cavity. The inner walls of the 
lateral ventricles, which answer to the septum lucidum, are 



448 THE ANATOMY DF VEETEBRATED AjrCMALB. 



thick, while the fornix is comparaUvcly thin and slender. 
The anterior commiasTire ia very atoiit. la this eircna' 
stance, as in the small eorpns calloaum, the brain of the 
Hedgehog closely approaches that of the I>idelphia and 
Omithodelphia. There ia no trace of a posterior comn, of 
oalcarine fiasure, and the lateral ventricle extends forwardi 
into the olfactory lobe. The optic nerves ai-e very slender; 
the corpora genienlata externa are large and prominent ; \im 
nates are smaller than the testes, and transversely elongated. 
The cereheUum has a large vermis and small lateral lobw; 
the flocculi are prominent and are lodged in foasffl of tie 
periotic hones. The pons Varolii is very small ; the eorpon 
trapewtidea proportionally large. 

The spinal cord is remarkable for ita thiclmeBH, and, at 
the same time, for its brevity, as it ends in the middle ol 
the dorsal region. As a consequence of this arrangemml 
the Cauda equirta is particularly large and long. 

The stomach ia simple, hut the mucous menabrane of lie 
considei'able cardiac dilatation is thrown into numeroos. 
and very strong, longitudinal rug». The intestine ia abont 
ail times as long as the body, and presents no diatinctjon 
into small and large; nor is there any ccecnm. The liver 
is divided by deep fissures into sii lobes; a central one which 
bears the gall-biadder, a bifid spigelian lobe, and, on eadi 
aide of these, two other lobes. The pancreas is a, large and 
irregularly rami£ed gland ; and the spleen is elongated and 
trihedral. 

The pericardium is extremely thin. The arteries arise 
from the arch of the aorta, as in Man, by an anonyma, > 
left carotid and left subclavian. The course of the internal 
carotid is remarkable. When it reaches the base of the 
skull it enters the tympanum and there divides into two 
branches, of which one traverses the stapes, and passing 
forwards in a groove of the roof of the tympanum, ente« 
the akiill and gives rise to the middle meningeal and 
ophthalmic arteries. The other branch passes over the 
cochlea, enters the skull by a narrow canal near the teBa 
turcica, and unites with the circle of Willis. 



THE SPLANCHNOLOGY OP THE HEDGEHOG. 449 

The external jugular vein is very much more capacious 
than the internal, the latter being very small and hardly 
traceable to the internal jugular foramen. It is by the 
external jugular vein, in fact, that the great mass of the 
blood within the skuU is carried away, a foramen in the 
squamosal bone allowing of a free communication between 
the external jugular vein and the lateral sinus. There is a 
left superior vena cava, which winds round the base of the 
left auricle, receives the coronary vein, and opens into the 
right auricle. The vascular system thus retains many 
embryonic characters. 

The right lung is four lobed ; the left may possess from 
one to three lobes. 

Two ossifications, one on each side of the opening for the 
aorta, occur in the diaphragm. 

The testes of the male do not leave the cavity of the 
abdomen, but they descend as far as the inner side of the 
inguinal ring, to which they are connected by a short 
gubemaculum and cremaster. The vasa deferentia de- 
scend to the base of the bladder and then enter a hollow 
muscular sheath on their way to a " chamber," which is 
lodged in the distal end of that sheath. This " chamber" 
passes into the penial urethra; the cystic urethra opens 
into it by a narrow slit in its front wall; and it receives the 
ducts of three pair of appendages. The proximal pair 
consist of a multitude of ramified tubuli, which have been 
found to contain spermatozoa, and are usually regarded as 
.vesiculae seminales. The middle pair (the so-called " pro- 
static glands ") have a similar structure and have also been 
observed to contain spermatozoa. The lowermost pair are 
Cowper's glands. The " chamber " appears to represent the 
urogenital sinus of the embryo, which has not become 
differentiated into prostatic and bulbous urethra. 

The ovaries are inclosed in wide-mouthed peritoneal sacs, 
and a ligamentous band, the diaphragmatic ligament, ex- 
tends from the ovary to the posterior surface of the dia- 
phragm. The comua uteri are large and long. There 
are five pair of teats ; the anterior pair being axillary and 



■too THE ANATOMY C 

the posterior ingninal. The other three pair are equidiatant, 
and lie along the venti'al aurfaoe, internal to the edge of ik 
orbicularis pannicBli. 

Like the Bodentia, the IngecUvora have a great diversitj 
of habit; some OaleopUhem flitting throngh the air after 
the fashion of the fl^ying Squirrels; some aj-boreaJ, as tbe 
IVtpoj/O!; some terresti-ial and cursorial, like tlie majori^ 
of the order. A few are awinuners; and some, like the 
Mole, are the most completely f oasorial of njammala. 

The moat aberrant form of the Inseciivm'a is the genm 
Galeopitltecii$, essentially an Insectirore of arboreal and 
frugiTorous liahit, with very long and slender Umba. These 
are connected with one anoEher, with the aides of the neek 
imd body, and with the tail, by a great fold of the int^^- 
ment, which is called palagium ; and, unlike the web of tbe 
Bat's wing, is hairy on both sides, and eitenda between the 
digits of the pes. By the help of this great pai-achute- 
!ike expansion, the Oahopitheous ia enabled to make float- 
ing leaps, from tree to ti'ee, through great disrtaneeB. When 
at rest, the GaieopiiAert snapend themselves by tlieir fore 
and hind feet, the body and the head hanging downwards: 
a. position which is sometimes assumed by the Marmoaeta 
among the Friniatee. 

The fore limbs are slightly larger than the bind limbs. 
There are four axillary teats. Tbe male baa a p^aidenl 
penis and inguinal scrotal poncbes. The pollex and tbe 
hallus are short, and capable of considerable movement in 
adduction and abduction, but they are not opposable; and 
their clawa are like those of tbe other digits. 

Tbe occipital foramen is in the postei'ior face of the 
skull. The orbit ia nearly, but not quite, eucirdcd by 
bone. The lachiymal foramen ia in the orbit. The bony root 
of the palate ia wide and its posterior margin ia thickened. 
There is a strong cuiTed post-gleaoidal process of the 
squamosal, which unites with the mastoid, beneath the 
auditory meatus, and restricts the movement of the man- 
dible to the vertical plane. A longitudLniJ section of tbe 
atcuU ahowB a, large olfactory chamber projecting beyond 



r 



HALEOPITHECUS. 461 I 

that for the cerebral lobes, and two longitudinal ridges npon 
the inner face of the latter, pj-ove that these lobes must i 
ha-ve poBBeased corresponding sulci. The tentorial plane i' 
nearly vertical and the floccular foasse are Tcry deep. 

The ulna is Tery slender inferiorly, where it becomes | 
ankylosed to the distal end of the radius, which beara the 
carpus. When the ilia are lioriKontal, the acetabula look 
a little upwards and backwards as well as outwards. The 
fibula is complete. Aa in. the Sloths and woat Frimateg, 
the navicular and cuboid readily rotate npon the astra- 
galus and calcaneiim, so that the platUa pedis ia habitually ■ 
turned inwards. 

The dental formula is i. ^ e. -^ p.Tii. m. °-£^ = 34. 

The outer incisor, in the upper jaw, has two roots, i 
peculiarity which is not known to occur elsewhere. The 
oaninea of both jaws also have two roots, aa in aome other J 
Inseclivora. The lower incisors are single-f anged ; and I 
their crowns are broad, flat, and divided by nnmeroug I 
deep longitndinal fissures, or " pectinated." 

The length of the whole alimentary caniil from month to 1 
anus is not more than six times that of the body. The 1 
sacculated wecnm is as long as the stomach, and its capacity ] 
must be greater than that of the latter organ. 

Galeopitkecug has, at one time, been placed among the ] 
Lemurs, and at another, among the Bats. But the res 
blancea with the former are general and supei'ficial, and 
the difi'erencea in the form of the brain, the dentition, the I 
atructure of the limba and of the akull, exclude it from] 
the order of the Promotes. 

Galeopilliecus agrees with the Bats in the dispositioi 
the tail, and in the eiiatence of a patagiimi provided with 
special mnsclea. Further, in a slight obliquity of the 
acetabula, such as is seen in its extreme development in 
the Bats i in tie impei-fect condition of the ulnat; audit 
the pectoral position of the teata and the pendent penis. 
Both of these last, howerer, it must be recollected, are i ' 
Frimatio oharaoters. Finally, the eomewhat Btmilarly pec- 



453 THE ANATOMY OF TERTBBEATED AHIMALS. ' 

tinated lower inuisor teeth are found in the Oheiraptena 
genera, Dipkylla tmd Demiiodus, 

But Guleopitliemig differe from the Bats completely in 
the atmcture of the fore Itinba ; in the position of the hiid 
limbs and the absence of a calcar; in the two-fanged onUt 
inciaora and caninea ; and in the presenae of a cceemn. 

On the other hand, the peculiaritieB of the skull ml 
brain are mainly insectivorous, aa is the two-f an^d cul 
and I aee no reaBon for dissenting from Prof. Peters' 
that Galecrpifhecus belongs neither to the Primates, m 
tie Cheiroptera, but that it ia bji aberrant Inaectivorw. 

With respect to other Inaedivora, it ia worthy of note, 
that Ma,crMeeU3A!9 has the radius and the ulna ankyloerf. 
The Toipaym posses a large ccecuni. Chrysochlora iis 
pectoral mammary glands ; Centeteg and the Moles have ^ 
penis pendent. 

The Fapayis are soft-furred, long-tailed, tree-loving 
animals, with complete bony orbits and a large cteoum 
and are those Ingectivora which moat nearly approach tbe 
Lemiu-a. 

Tlie Shrews {Sonces] moat nearly resemble Itodents onl- 
wardly, being very like smaU mice. The zygoma a I 
imperfect, the tibia and fibula are ankyloaed, and the puUt 
bones do not meet in tlie aympbysia. There are sixteen to 
twenty teeth in the upper jaw and twelve in tbe mandibli!. 
Oaninea are absent, and there are six incisors above and 
four below. The inner lower incisors are greatly elongated 
and proclivous, and some of the teeth not unfrequentJj 
become ankylosed with the jawa There is no coecnm, and 
peculiar musk glands are sometimes developed at the aides 
of the body. 

The Moles (Talpinir) have no external ears, and tho eye« 
are rudiment^y. The fore limbs are much lajrgcr than the 
hind, and are inclosed within tlie integument np to the 
carpus. The palmar surface of the broad manus ia turned 
outwards and hackwarda. 

The manuhrium of the atemum is very broad, and its ven- 
tral surface gives liae to a Btiong median creat Theaeaimlft 



THE INBECTIVOBA. 453 

ie aB long aa the Lumerua and the radius together. It is 
triquetral and posaesaes an acromial procesa, but no distinct 
coracoid. The clavicle, which ia very strong, is perforated 
by a great foramen, and at the middle of its posterior mar- 
gin sends off a truncated re-entering proeeas. Proiimally, 
it fumiahes an articular surface for the hnmerua. In the 
carpus there is a distinct c&atrcde, and a large accessory 
C-shaped bone lies on its radial aide. The pubes are sepa- 
rate at the symphysis, and an accessory styloid bone ia 
connected with the naviculare of the foot. 

The diatribntion of the Inseetivora is singular in this 
respect, that although they are met with, under very various 
climatal conditions, throughout the Old World and North 
America, there are none in South America or Australia. 

In the fossil condition they are not certainly known to 
occur in strata older than the tertiary. 

Fig. 109. 




Fig. 199,— The akeleton of a fifing Fra (Pierqjmf). 



4S4 THE AHATOMY OF 

m. The Cheibopteea. — The Cheiroptera maj be » 
garded as exceedingly modified Inaectivora, having tlar 
nearest ally in Gahopitliecas. 

They poasess one or two pair of pectoral teats ; and the ins 
limbs are very long, some of the digits particularly belt 
immensely elongated. There is a patagi-uim, or espauBBji 
of the integument, uniting the fore limbs with the bodj, 
and extended, as a membranous web, between the elongattJ 
fingers. Of these the third, fourth and fifth, and ra; 
frequently the second, are devoid of nails. The polla 
always has a claw'lilie nail. When the animal is restiif 
upon the ground, the thigh is twisted upwarda and back- 
wards, in euch a manner, that its extensor face loab 
forwards, and its flejcor face backwards. In conBequencc 
of this the knee looks upwards and backwards, and t^ 
toes are turned backwards and slightly outwards. TTndcT 
the same ciromUBtanoes, all the digits of the maiins an 
flesed upon their metacarpal bones ; and the f olded-np wwg 
rests against the aide of the body, whilst the pollex, willi 1 
its claw, is extended forwards. la this position the animal 
ahwfflea along, with cojisidei-able rapidity; hauling itadf 
forward by the claws on the polHcea, and shoving itseU ^ 
along, by extending the hind limbs. 

The favourite attitude of a Bat, when at rest, however. 
is tliat of suspension by the claws of one or both legs, with 
the head downwards, and thepaioffiu™ folded o 
cloak. The most active movement of the Bat is effected bj 
flight, the fore limbs being estended, and the paiagivm, 
which they support, playing the part of the feathers of > 
bird's wing. 

The cervical vertebrBe are remarkably large in proportiwi 
to the others, but, ae in the rest of the vertebral colnmn, 
the spiuouB processes are very short. Tbo ribs are long 
and cnrved, so as to include a relatively capacious c" 
The manubrium of the sternum is very wide, and the 
middle of its imder surface raised into a crest. In the 
himhar region, the vertehi-al column is bent, so as to be 
e forwards and to describe almost the qaartec of a 



. THE CHEIBOPTEBA. 455 

circle. As a consequence, the axis of the sacrum is at 
right angles to that of the anterior thoracic vertebrae. 

In the skull, the orbit is not divided by bone from the 
temporal fossa, and the premaxillae are relatively small, and 
sometimes altogether rudimentary. 

The clavicles are remarkably long and strong, and the 
broad scapula has a strong spine. The ulnae are imper- 
fect distally, the carpus being borne altogether by the 
radius. There is only a single bone in the proximal row 
of the carpus, the pisiform being absent. Those digits of 
the manus which are devoid of nails, possess not more 
than two phalanges. 

The pelvis is very narrow and elongated, and the pubic 
bones are widely separated at the symphysis, as in some 
Insectivora, The anterior caudal vertebras and the ischia 
are frequently united. The axes of the acetabula are 
directed towards the dorsal side of the body as well as 
outwards ; whence, in part, arises the peculiar position of 
the thigh, which has already been described. The fibula is 
rudimentary, its upper part being represented only by 
ligament, and there is an elongated bone, or cartilage, 
attached to the inner side of the ankle-joint which lies 
in and supports the patagium, and is called the calcar. 
The distal moiety of the tarsus readily rotates upon the 
asti*agalus and calcaneum, permitting the sole to inm 
inward with much ease. 

All Cheiroptera possess three kinds of teeth, incisors, 
canines, and molars ; and the intestine is devoid of a coecum. 

The heart is provided with two superior cavae, a right and 
left ; and the smooth cerebral hemispheres leave the cere- 
bellimi completely exposed. 

The testes are abdominal throughout life, or may 
descend into the peiinaeum, but there is no true scrotum. 
The penis is pendent. There are vesiculae seminales. The 
form of the uterus varies, being sometimes rounded and 
sometimes two-homed. 

The Bats are ordinarily divided into the Frugivora and 
the Insedivora, 



■156 THE ANATOMY OP VEETEBEATED AU-IMAI.3. 

u. The Fi-asivora live, as their name implies, excliiaivdj 
upon fmita. With the single esception of Sypodurr. 
the genei-a embraced in this group have a, aail on the secunl 
digit of the mauua, and the crowns of the m.ol^u' toetk 
which BiK>n wear down, are, when entire, diyided 1 
longitTiiiinal fuiTow, 

The incisors do not exceed ^7;. 



The pyloric portion of the stomach is immenaelj e 

The nose has no foliaccoaa Ebppendages, and the well' 
developed piana of the eai- has the ordinaiy form. neitiB 
the tragus, uor any other part, being unusually developed. 

These Bata are confined to the hotter parts of the OIJ I 
World and of Australia, where, from their dog-like h?adt I 
and reddish colour, they are known aa " Plying Foiee" I 
(PferqpuB, Sarpyki, Ac.) I 

h. The division of the laaeciivora contains Bats which, for I 
the moat part, live upon insects, though some deliglit ii 
fruits, and others suck the blood of larger aninmla. 

The second digit of the manue is devoid of a hr.j I, am 
sometimes ia without any bony phalanges. 

The stomach is usually pyrif orm, with a moderate cai^iu 
enlargement. The molar teeth almost always have such ■ 
pattern aa is observed in the typical Inaeiitivora, and d 
eioeed sii, or fall below four, on each aide above and belov. 

The incisors are ordinarily j:^ or — but their number 
may be much reduced. 

The integument of the nose is developed into an appen- 
dage which is sometimes very large and leaf-like, and the 
tragus of the large ears ia often similarly modified. IHie 
tail is often long, and sometimes prehensile. 

The genera DesmoAue and Biphylla, [oi which the group 
Hcsimtt'yphiUwi has been formed) are the most completely 
blood-sucking of all the Bats in their habits. Ttiey have a 
pau* of enormous, sharp- pointed, upper incisors, while 
the four lower incisors ai-e small and pectinated. The 



457 

9 very lai^e and sLarp, and the molars, which 
are reduced to two ahoTe and tbree below, on each Hide,, 
have their crowns converted into sharp longitudinally dis' 
poac^ ridges, like the edges of scissors. In Destitodua, the 
very narrow ceaophagca leads into a, stomach which would 
be of extremely small dimenBions, were it not that its 
cardiac end is dilated into a great sac, which is longer 
than the body, and lies, folded up on itself, within th* 
cavity of the abdomen. Into this sac it would appear 
that the blood swallowed by the animal at first passes, to' 
be tience slowly drawn along the intestine. 

Mr. Darwin* thus speaks of the habits of Deemodiu 
JJ'Orbignyl : 

" Tlie Vampire Bat is often the cause of much ti-ouble 
by biting the horses on their withers. The injury is gene- 
rally not BO much owing to the loss of blood as to the in- 
flammation which the pressure of the saddle afterwards 
produces. The whole cireumatance has lately been doubted 
in Engliind. I was therefore fortiinate in being present 
when one was actually caught on a horse's back. We were 
bivouacking late one evening near Coqnimbo, in Chili, 
when my servant, noticing that the horses were veiy rest- 
less, went to see what waa the matter, and fancying ha 
could distinguish something, suddenly put his hand on the 
beast's withers and secured the Vampire. In the morning 
the spot where the bite had been inflicted was easily distin- 
guished, from being slightly swollen and Moody. The 
third day afteiTvarda we rode the hoi'se without any ill 

IV. The Pbimatbb. — The Frimateg have two pectoral 
uamnuE, and, rarely, additional ones upon the abdomei^ 
Incisor and molar teeth are always present, and, with one 
exception, canines. The incisors are never more than two, 
nor are there more than three premolars and three molars, 
on each side, above and below. 

Saving individual exceptions, which o 
1 may be regarded as abnormal, the hallux posHessea 9 J 
" Voyage of Hm Seogle," 



1 



458 THE 4NAT0MY OF VEHTBBRATED ANIMAiB. 



flat niuJ. The ha31ui differs in form from the other digia 
, of the foot, and is bo disposed ui to be capable of mon 
or less eitenaive motion in adduction and abductionj aii£ 
very generally, it ia oppoeable to the other digits of the fort 

The PWjnnfce are divisible into — a. the ZJemjwMte, i.tk 
Simiadtx, and c. the Anthropidae. 

a. The first of these diTisions, the Letn/uridtE, is mun 
widely separated, anatomically, from the other two, tlm 
these are from one another,* and it eontaina some fotni 
which veiy closely appromnate to the Insectivora, wiik 
others are neai'ly affined to the Badentia. 

All the Lemvrido! are littbitually quadripedal, have tkl 
integument fuiTj, and are usually provided with lon^taib 
which are never prehensile. They are devoid of diet* 
pouches and of callous patches upon the integum.ent covn- 
ing the ischia. 

The fore limbs are elorter than the hind limba. Li 
the foot, the hallux is large and opposable, and tJie aeami 
digit differs from the rest in size, and in the claw-lik 
form of its nail. The fourth digit is usuaOy longer than tJir 
others, the difference being especially marked in the iiea. 

In the akuU, the brain-case is small relatively to the face, 
and ia contracted antei'iorly. If a straight line drawn froa 
a point midway between the occipital condyles, through th* 
median plane of the skull, to the junction of the ethmoid 
and presphenoid, in the floor of the cerebi-al cavity, be 
tenned the had-cranial axis; and if the planes of Uw 
cribriform plate of the ethmoid, of the tentorium cerebelli. 
and of the occipital foramen, be respectively termed th** 
ethm«idal, iertim-ial, and oedpital pla'neB ; then, the greatest 
length of the cerebral cavity hwdly exceeds the length 
of the basi-cranial axisj and the ethmoidal, tentorial, and 
occipital planes arc very much inclined to that axis. ' 
upper aperture of the lachrymal foramen lies upon the 

* On the strength of these (lifFerenccB Al. Grstlolpt relegated the 
Lemura to the Inteciicora ; and Mr. Mivart, in hla valnalile paper 
" (In the Axial Skeleton in the Primatea," published in the Proccedinis 
of the Zoologicnl Society for 185.1, divides the i^imalM into two sa& 
ofdera, Ltmvradra and Antfirojujitka. 



THE LEUUBm^. 



459 



|?6ice, outeide the front mar^ of the orhit. The frontal and 
e jugal bones are united behind the orbit, but a mere, 
X of bone results from their nniou; imd it is ao ua.i 
K'bbat the oihit and the tempond fossa are in free < 
R.launioation. The bony palate is elongated and, in niany ', 
i, ita posterior fi-ee edge is thickened. 
. The lateral proceaaea of the atlaa are, uaually, expanded. \ 
~~ B lumbar region of the spine ia elongated ; the vertebra I 
mpoaing it, in Bome cases, being as many as nine. There cu 
les in the carpus. The ilia are narrow and elongated, 
Uid the iachia are not everted. In most Lemurs, the tarsal 
wnes reaemble those of the other Primaiea; but, in OtoUenva 
md Tarshia, they have undergone a modification, a parallel 
> whieh is not to be found among Mammals, but must 
e sought among the Batraekia. When the distance be-'' 
n the heel and the digits ia gi'eat in other MammaUa,. 
hthe elongation afFecta the metatarsal bones and not thQ^ 
tarsua; but, in theae Lemurs, the caLcaneum and the : 
cutare are prolonged, as they are in the Proga, 

The sablingva. a process of the mut 
floor of the month, developed between the apes: of t 
tongae and the symphysis of the mandible, acquires s 1 
considerable size, and is often denticnlated, or comblike. at .1 
its free end. The stomach is simple, with the cardiac and 
pyloric apertures approximated. The ctecum is long, and 
has no vermiform appendage. 

In many Lemurs (Stenopg, Nyeticebue, Perodicticiis, Arcto' 
cebvs, TarHns) the great arteries and veina of the limbs 
break np into retia inirdbilia formed of parallel branches. 

The ventricles of the larynx may be enlarged, but there I 
are no great air sacs, auch as exist in many other Primates. 

In the brain, the cerebral hemisphei'es are relatively small ] 
and flattened, and have narrow and pointed frontal lob 
They are so short SiS \o leave the cerehellnm largely i; 
covered. The gyri and sulci are scanty, or absent, upon the I 
outer surface of the hemiapheres, but the internal i 
eihibits the calcarine sulcus. The large olfactory k 
project forw&rda beyond the cerebral hemiE^heres, 



4r60 THE ANATOMY OP VERTEBRATED ANIMAI<S. 

The pendent penis of the male commonly contains a 
bone; the testes are lodged in a more or less complete 
scrotum ; and vesiculse seminales are generally present. 

In the female, the uterus has two long comua, and the 
urethra traverses the clitoris. Sometimes there are one or 
two pairs of teats on the abdomen, in addition to the ordi- 
nary pectoral pair. 

The Lem/wridcB are distinguishable into two families, the 
Lemurini and the Cheiromyini. 

In the Lemurini J the pollex is large, opposable, and almost 
always has a broad, flat nail. 

The usual dental formula is i. ^tt^c.t-. 7?-^. w- r-r, or — r. 

2 2 I'l-*^ 5*5 6*6 

The upper incisors are vertical, and the pairs of opposite 
sides are generally separated by an interval. The upper 
canines are large and pointed, and very different from the 
incisors. The lower incisors are close set, laterally com- 
pressed, long and proclivous, and the canines, which re- 
semble them in form and direction, are closely applied to 
the outer incisors. When six grinders are present, the 
anterior three are premolars. The anterior premolars, and 
sometimes all of them, have triangular and sharp-pointed 
crowns; the first premolar of the lower jaw, in fact, re- 
sembles a canine, but its true nature is shown by its biting 
behind the upper canine, not in front of it. 

"Very generally the crowns of the upper molars are qua- 
dricuspidate, and an oblique ridge passes from the antero- 
extemal to the postero-intemal cusp, as in the highest 
Primates; while, in the lower jaw, there are either two 
transverse ridges, or longitudinal crescents. The cusps of 
the molars are usually much produced, as in the Insectivora, 

In the CJieiromyinif the pollex is not truly opposable, and 
its nail is claw-like and resembles that of the other digits. 
All the digits of the pes, except the hallux, have compressed, 
claw-like, nails. The middle digit of the manus is much 
more slender than any of the others, and is longer than the 
fourth. The long axis of the articular head of the mandible 
is antero-posterior. The dentition differs from that of all 



461 I 

the other Lemurs (and indeed from that of all the other I 
Frimates), and reaemhleB that of the Bodents. 

Thus there is only one pair of inciaora in each jaw,* and I 
tbeae gi'ow from persistent piilpa and have a thick layer ol • 
enamel on their anterior facea, whence they wear to aharp 1 
ehisol edges, like the ineisora of the BodenHa. No canines J 
are developed, and there are four grinders with simpleS 
cro'wna on each aide above and below. 

The formula of the niilk dentition is d.i. 575 d.e. -— 



The Lemurida are confined to Eastern Asia, Madagaaear, I 
and South Africa; Madagascar preaenting the greateatj 
number and diversity of genera and apeciea. 

6. In the great group of the Simiadts^, which contains the 1 
Apes and Monkeys, the attitude is aometiioea habitually 1 
quadrupedal, the axis of the body being horizontal i but, 1 
in a few apecies, the trunk is habitually held ii 
cliued position, and the animals readily aeaume the erecti 
attitude. 

The Simi'idie are eometimee terrestrial in habit, andfl 
good runners, but they are always excellent climbera, on4 1 
in some casea, they are necessitated by their organi-i 
zati'on to be almoat aa thoroughly arboreal as the Slotha. 

The hallux is always much shorter than the second digit 
of the foot, and capable of very free movement in adduction 
and abduction. 

The series of the teeth, in each jaw, is inteimpted by a 
diaateniu. in front of the canine in the upper jaw, ; 
behind it, in the lower ; and the canine teeth e 
than the othera, the points of their crowns projecting fol 
r less distance beyond the reat. 

In the akull, the length of the baai-craniul a 
) than half the extreme length of the cavity v 

jntaina the biwn. The absolute capacity of the ci 



gf iuclBoiB in the mHDiUbla. 




! AKATOMT Oy YEKTEBEATED AJIQUI^. 



i less titan fortj rrubic inches ; and, if there la any diffs* 
nee in the length and abundance of tLe hair which corai 




the body, it is longeat on the bat^k. The uterus is ( 
divided, and the clituria is not pei-forated by the uretiiM. 
The teats are only two in number, and they are pectoraL 

The Simiadte are divisible into three familieB — the Art^ 
[litliecini, the Phityrrhini, and the Catarrhini, 

1. The AroiopUheei'rU, or Marmosets, are Bmoll, thiddj 



THE AEOTOPITHECINI. 

irred, long-tailed, habitually quadiiipedal. SquiiTgl-like, I 
nimala, which are found onlj in South America. Nona 1 
( them are provided with cheek pouches, nor poHsess hare 1 
■md callous patchea of integument over the ischia. The 1 
nra aro large aoid hairj. and the nose ia flat and hroad, a 
a the Platyrrhini. 
The fore limha ore shorter than the hmd Umba. The>l 
pollex ia not opposable, nor susceptible of extensive abdud'] 
tdon from the other digits, which it reaemblea in being pro- ■ 
yided with a sharp curved claw. The i 
^nently, ie a mere paw, and the term " hand " is not appli- 
i08ible to it. The hallux of the foot is very small and ie 
■vided with a flat nail. The nails of all the other digits of 
ea are falcate. The plantar surface is very long, ajid 
the digits are veiy short. It follows from these facta that 1 
the term " quadrumanona " is not applicable, in any sena^ i 
to the Marmosets. 

The akull is remarkable for the smooth and rounded 
surface and relatively large size of the hrain-caae. 
Although the orbits are large, the hrr.w ridges are incon- 

Jspicuciua, and the occipital region of the skull projects sc 
far backwards that the occipital foramen may lie com- 
pletely npon the under surface of the skull, towards the 
junction of its middle and posterior thirds; and have ita 
i plane almost horizontal, when the face looks forwards. The J 
orbit is almost completely abut off from the temporal fosB&'fl 
by bone. 

The hyoid i-esemhles that of the Lemurs, ita body being V 
narrow and much arched from side to side, while the antorioi 
oomua al'e strong. 

There are usually nineteen doraolumhar vertebrae, and 
the transverse proceasea of the atlua are somewhat bi-oad I 
and flattened. 

The dental formula ia t. — c. 
Thus the number of the teeth is the same aa in Man and the 
Caiarrhini ; but in the number of the premolais and molars 
the ArciopitkeeM differ from both tim Catatrkini and the 




iGi THE ANATOMY OF TEETEBKATEB ANrMAXS. 

Platyh-hmi, haying one premolar moi-e than the former aad 
one true molar fewer than the latter. In Sapale, the loww 
tneiBiire are pri>elivoiis; and the canines are approxunuted 
to them, and similarly inclined, as in the Lemurs. 

Although the manua is a paw and the polles is nul 
OppOEahle. this digit has its proper abditclor, adductor, and 
long and short flexors. The etistence of a proper oppouau 
of the poUex is douhtful, but thei*e is an opponent ntimnt 
digiti. The flexor Itmgiig is completely united with thejl««»f 
firofvndvs digitorum, hut the tendon for the pollex 
off on the radial side iuetead of on the nlnar side, ae 
in 8ome of the higher Simiadai. The (scfeneor secvndi inler- 
nodii pollicw ia united with the etdengor indicis, and tbe 
extensor minimi diyiti givej off shpa to the third, fonrtii. 
and fifth digits, ho that there is a complete set of deep ei 
teuBorB. The four dorsal and three palmar initroasei are sol 
distinctly subdivided, but they send slips to the extensor 
tendons. 

There are four peronrei ; p. Itmgtis, p. hrevis, p. quitaii, and 
p. qvinti digiti. The flexor brevU digilomm, of the pea bw 
one division which arises from the colcaneom and goes to 
the second digit; the other three heads arise from tfce 
tendons of the flexor perforam. The flexor ni 
nishes almost the whole of the long ilexor tendons o£ tl« 
hallux, the^eaior longng digiiorum supplying the perforating 
tendons of the second and fifth digits ; while the^fteawr Aat 
lacis longus gives off the corresponding tendons of the 
third and fourth digits. The interoe»ei, in the pee, s^Mflr 
to be represented only by the paira of muscles which act 
ae short flexors of the basal phalanges, and these Ue al- 
together upon the plantar aspect of the five metatATsal 
bones. The hallux has no special addvctor, nor is there 
any trantvemts pedie. In fact, the pea is almost as com- 
pletely a " paw " as is the manus. 

The brain has long and relatively large cerebral heini- 
spheres, the posterior lobes of which project far beyond 
the cerebellum, and thus completely hide it, in the upper 
view of the brain. The external surfaces of the hieoi- 



THE PLATTEBHINI. 



inner face of each, hemiaphere, the calearine fisanre is deep 
a.nd giTea riao to a wcil-marked hippocampus ■minoT within 
the poaterior comu of the lateral ventricle. The eoiynw 
calloBma has about a third the length of the hemiapheres. 
The sfljitiMH Iwadimn is very thick, and the precommisBural 
fibres abundant. The vermis projecta beyond the lateral 
lobea of the cerebellum, and the,^{ciccu2i are large. 

2. ThePIa^rrhini are eaeentially quadrapedal and planti- 
grade, though some, like the Spider Monkeya {Aieles), oeca- 
sionally aasume the erect poature. They all poBseaa taila, 
and in Home genera {e.g. Atelea) thia organ becomea verf 
flexible and moacular. and the nnder snrface of its extremity 
is devoid of hair and highly sensitive. The tail, thus modi- 
fied, IB a powerful prehensile organ, and servea as a fifth 
hand. The partition between the noatvila ia broad and 
separatea them widely, ao that the noae ia remarkably wide 
and flat, whence the name of the gronp. The ears are 
rounded and bare. There are no cheek pouches, nor ischial 
callosities, in any Platyrrhine Monkey. In most, the f or^ 
limbs are shorter than the hind Umhs, but the reverse ig' 
the case in the Spider Monkeys. The poUex differs 
from the other digits than it does in the CatarrhinL It ft 
more nearly parallel with, and in the same plane as, tha 
other digits of the manus ; and though capable of extensive 
adduction and abduction, can hardly be said to be truly 
opposable. The hallux ia large, and suaceptible of ext^- 
eive movements in abduction and adduction. 

The number of the dorso-lumbar vertebne varies from 
seventeen to twenty-two, the greatest number being pos- 
Bsed by Wyciipif feectta, which has 22 (14 
\ tboae forma which have prehensile taila the terminal 
I ivertebrffi are flattened from above downwards. The arti- 
k «nlar aurfaee of the head of the humerus looks more baek- 
I wards than inwarda; and, not unfrequently, tbi 
L foramen above the inner condyle. The cai'pus containa 
o bones. The poUez. is generally complete, bnt, 

2 H 



t65 ^H 

'eU ^H 
the ^H 



-H e or 13 + tj. in i 

the terminal caudal 
nwards. The arti- I 

LB looks more back- | 

uently, there is a ^^^B 
le eai'pus containa ^^^H 
:plete, bnt, in Atele^^^^^ 



4ti6 THE ANATOMY OF VEETEBEATKD ANIMAiS. 

it ie reducod to a Bmall metacarpal (tonhicb, uanallj, a single 
minute iiodulu,r phalanx ie artictiluted), and is completdj 
hidden beneath the integument. The pelvia is, generaUji 
elongated, and the anterior ramus of the pubis lies at righ 
angles with the long axis of the narrow ilium. The tuber- 
ositiea of the iachia are everted, but not rugose. In Atelti. 
the pelvis IB broader, and the pubis forms a more open 
angle with the ilium. The calcaneal process is alwajs Terj 
short, and compressed from side to side. 

The brain-case is rounded and devoid of strong crests. 
There is no distinct mastoid process, and the styloid is not 
ossified. The coronal suture is generally V-rfiaped. the 
apex of the frontal hone extending far back on the vertei 
of the skull. The alisphenoid and the parietal bones unite 
upon the side walls of the skull. The externa! auditoiT 
meatus is not onsified, the tympanic bone retaining its fistal 
hoop-like form. The frontal bones approach one another 
on the floor of the skull, but rarely unite over the junction 
of the presphenoid with the ethmoid. On the inner bup- 
face of the periotic bone there is a fossa overarched by the 
anterior vertical semicircnlar canal, in which the ftoccnliu 
rests. In Aieles the greater part of the tentorium is osidfied. 
In other respects, the skull presents extraordinary variatioii* 
among the Platyrrhim ; the two extremes being presented by 
the Howling Monkeys (Myeetes) and the Squirrel Monkey* 
{Ohj-yBothrix). In the former, the face is very large and 
prominent, with a low facial angle. The roof of the brain- 
case is depressed; the plane of the occipital foramen ia 
almost perpendicular to the basi-cranial axis ; and that 
of the tentorium is very much inclined. The occipital 
condyles are, consequently, situated at the posterior end 
of the basis eranii, and the baai-craniol axis is as long as 
the cerebral cavity. In ChrysotKrix, on the contrary, the 
face is relatively smaD, with a high facial angle; the 
bimn-case is moderately arched; the plane of the ten- 
torium ia horizontal, like that of the occipital foramen, 
which lies but little behind the middle of the base of tie 
sknll. The basi-cranial axis is much shorter than tlie 



cerebral oavitj. The premaKillo-iaa,sillary suture diBappeawi. 
early in Cebus, 

The fominla of the adult dentition ia i. ^ e. — p.m. ^ 
th. — = 36. The crowns of the molar teeth usually have 
two ti-ansTerae ridges, ending in four auflpa. In the upper 
molars of Aielei and Mycetes an obliqne ridge civasaes the 
crown from the antero- external to the postero -internal 
cusp. The permanent canines usually make their appear- 
ance before the last molar. 

The stomach is simple, the ccecnm large, and devoid otM 
any vermiform appendix; the liver ia nanally five lobed}^ 
and the kidney has a ainglo papUla. 

The ventricles of the larynx are not nsnally developed^ J 
into air-aacs. In Ateles, however, a median air-sac ia deva- 1 
loped from the posterior waU of the windpipe between tha . ■ 
cricoid cartilage and the first ring of the trachea. A very J 
remarkable modification of the hyoid and larynx taksB'l 
place in Mycetes. The eomua of the hyoid ; 
montary, but ita body is converted into a large thin-wall©3 
bony drum, the cavity of which communicates, beneath the 
large epiglottis, with that of the laryni. The thyroid 
cartilage is very large, and the cartilagea of Wriaberg and 
Santorini are replaced by a fibrous mass, which is imited 
posteriorly with its fellow of the opposite side. In additicn 
to the hyoidean air-sac the ventricles of the larynx t 
dilated and prolonged upwards, coming iuto contact aboTJ 
the laryni ; two pharyngo-laiTngeal pouches may be added ' 
to these. Mycetes is famous for the distance to which its 
howling voice can be heard in the South American forests. 

Although the poUes ia mdimentary and apparently func- 
tionlesH in Atelnt, all ita characteristic mnsctes {abductor, 
add/ttctor, fiexor hreuis, and opponeris) are present, escept the 
long flexor. 

IlaNyctipUliecas the pedal inierond areflacores brBUes, ""'' 
£e on the plantar surfaces of the metatarsal bonea, 8 
itibe Marmosets; but both the adductor haUuMi and t 
frwtBVsrsuir pedis are well developed. 



^ 




468 THE AKATOMV OF TEBTEBaA.TED ANCUALS. 

The brain varies remavkablj m different Plai^rrhiai. In 
Clirymthrlx, the cerebral hemiepherea project bejond the 
cerebellum to a greater relative extent thaji in any otliH 
Manunal. namely, by one-fifth of their total length. On 
tie other hand, in Mycetes, the cerebral hemispheres 
hardly hide the cerehelliim, when the brain is viewed tram 
above. 

In Cebas, the outer surface of the brain ia almoat u 
much convoluted as in the Catarrhine Apes. Ateles has the 
eitemal perpendicular fiesure almoet obliterated by Qx 
annectent gyri, and, bo far, exhibits a higher type of brain 
than the Caiarrhim; hut, in FUheeia, Ckrytothrix and 
Nyeiipithecut, the eitemal sulci gradually disappear, until 
the brain ia almoat ae smooth as in the Marmosete. 
the inner faces of the hemispheres, however, the internal 
perpendicular, the calloao -marginal, the calcarine, i 
the eoDateral sulci remain, vfhile, in the interior of the 
hemiapheres, the poateriorcomuandthe fiippocampjis tm 
are always preaent. 

The vermia of the cei-ebellum is large and projects 'b^^d 
thelevel of the poaterior margins of itahemiapherea; the/ofr 
citiiM ia large and lodged in a foaea of the periotio oesifici^ 
tion, en in the Marmoaeta. The upper enda of the pyramidi 
are separated by ctyrpora trapenoidea from the ■pons Varoln, 

The penia is usually terminated bj a largo button-shaped 
glana. The cavity of the tvmea vagiiialiB ia not aliut off 
from the abdomen, and the testes lie at the sides of, rathei 
than behind, the penia. The female Atelea baa a long 
clitoris, which depends from the vagina. 

The Platyrrhini occoi' only in the Auatro-Columbian ^»- 
vince, and are known in the fossil state only in certain 
cavea of that region. 

3. The Catarrhini.— The Bimadte of this division present 
a. great range of variation in most respects, but they agree 
in having the partition between the nostrils narrower than 
in the Flatyrrkini ; in poaaessing a bony meatus auditorins ; 
in the dental formtda i- ^ c 777 jJ.m- 5^ ™. ^, and in 




I 



THE CTNOMOKPHA. 

fceing inliabitantB of the old world. They fall into two v 
Jdistmct groups, the Cynmnorpha and the A-ntkropovwrpha, 

The Cynomorpka are distinguiehed from the < 
'group by being easentially qnadrupediil and, usually, pro- 
'iVided with a tail, which ia never prehensile. The femur and 
libia, takeu together, are longer than the humerus and the 
radiuH. The outer inferior incisorB are not Iwgor than tl ~ 
inner ones, but are often smaller. The crowns of 
molar teeth present two transverse ridges, a third 1: 
present, in some genera, on the last inferior molar. 

All the Cynonwrpha have ischial callosities, which s 
times attain a very large size, and are brightly coloured. 

The dorsolombar region of the spinal column is i 
towards the ventral aspect, and the lumbo-sacral a 
veiy lai^, The atlaa has narrow transverse pi-ocesa 
The ordinary number of dorsolumbar vertebrte is nin 
of which twelve, or thirteen, are dorsal; and seven, i 
lumbar. The middle cervical vertebrse have short spines 
■which are not bifurcated at their extremitieH. In the poe 

dorsal, and anterior lumbal', vertebraj. the ma 
and accessory proceBses may be enlarged and interlock. 
!Fhe long transverse processes of the hmibar vei-tebne bend 
forwards. The pacram usually contains only three an- 
kyloaed vertebra. The caudal vertebne vary in number, 
from three in Itmua {where they form little more than B 
coccyil, to as mMiy an thirty-one. In the ant«rior part o 
the tail the vartebrtB are provided with aubvertebral, ( 
chevron, bones. 

The thorax is laterally compressed, and the manubriiu 
of the sternum is broad j but the six or seven stemebnC 
which follow it are compressed and constricted. 

The skull presents a considerable range of variation. 
the Senmopitheei and Colobi, the frontal region is rounded 
the facial angle is comparatively lai^, and the i 
portion of the ramus of the mandible is high. 
Cijnocephali, on the other hand, tl 
IB become so much enlarged as to 
forehead; and the hoiizontal portion of the tarn 



470 THE AHATOMY OF VEETEBEATBD ANIMAX3. 

mandible ia much larger tban the ascending portion 
accordance witb. the great production of the upper jaw, tai 
the coLsequent low facial angle. In many of the Cjw- 
eephali, longitudinal obbcous ridgea are developed upon tie 
inasillie, and greatly increase the brntiahneas of tbdi 
aapect. St^ttat and tajnbdoidal crests may appear along 
the lines of the corresponding autures. There is no die- 
tinct mastoid pi'oceas ; and the styloid proceaa is not 
oaeified. The paidetal bonea do not unite with the alisphe- 
noida, being eeparated from them by the union of tie 
eqnamosala with the frontals. The brain case is flattened 
and elongated, and the convex roof a of the orbits projevl 
into it and greatly diminish the capacity of ita frontal 
portion. The olfactory foaste are very deep, and aometimee 
almost tubular. The two frontal bones aend thick procea8«t 
across the base of the skull, which unite over the junction 
of the presphenoid and the ethmoid, and thus nam 
entrance to the olfactory fose». The basicranial i 
shorter than the cerebral cavity, but ia atill proportional^ 
long. The occipital foramen lies in the poaterior sixth of 
the base of the skull, and it looks obhquely backwards and 
downwards. The premaxillo-maziUary autiire never diB- 
appeara until long after the aecond dentition is complete 
and may peraist throughout life. The palate ia long u 
narrow. The nasal bones are flat, and early ankylose ints 
one bone. 

The acapnia ia relatively longer and narrower than that 
of Man ; but the spine lies at right angles to the vertebnl 
border, and the aupra- spinous, ia much smaller than the 
infra-apinoaa fossa. 

The axis of the articnlar head of the humerus ia not 
directed upwards and inwai'da, but upwards and baekwardsj 
the bicipital groove liea on the inner aide ; and the shaft of 
the bone is so bent that it is convex forwards. In all these 
aharactera the fore Umb shows its relation to the function 
of support. The radius exhibits modifications wbtch have 
the same signification. Its proximal head ia transversely 
elongated, and lies somewhat in advance of tho ulna, 



THE OSTEOLOGY OP THE CYNOMOEPHA. 



471 



articnlating more largely witli the humeniH than 
higher Apes. The neck of the radius (hetween the head and 
the bicipital taheroaitj) Sta more closelj to the ulna, and 
hence the moTemeuts of pronation and supioati 
restricted. 

There are nine hones in the carpus. The pisifo 
rach elongated, making a sort of heel for the maun. 
ether with the cuneiforme, it fiimishea an articular fac« 
)r the ulna. The distal articular surface of the trapezium 
I saddle-shaped, and the pollei is asually complete, though 
lort relatively to the other digits. In Colohua it is radi- 

The pelvis is long and narrow. The ilia are narrow bonea 
ith much-eKOavated posterior and outer faces. Thai* 
crests generally lie opposite the transverse piMcesses of tlw 
penultimate lumbar vertebra. The long axis of the ilium 
and that of the anterior ramus of the pubis cut one another 
[ nearly at a right angle ; while the long axis of the ilium 
and that of the posterior ramus of the ischium lie neurly 
one straight line. The symphysis pubis is very long, and 
the subpubic arch correspondingly reduced. The postei " 
ends of the ischia. are everted, broad and rough, for the 
attachment of the callous pods of integument. The femur 
has a round ligament, The tarsus has not more than one- 
third the length of the foot, The calcaneal process is flat- 
tened from side to side, and has a pulley-like excavation 
upon its posterior eitremity. The tibial faeet of the astra- 
galus is inclined slightly inwards, as well as upwards, and 
its outer edge is raised. The distal division of the tarsus, 
consisting of the cuboid fmd navicular, with the cunei- 
form, bones, is capable of a considerable amount of rotatory 
motion upon the astragalus and the calcanenm. The ento- 
cuneifonu bone is large, and has a transvei'Sely-cunvex 
articular surface for the metatarsal of the hallux. Conse- 
quently the latter (which is short, reaching to only about 
the middle of the proximal phalanx of the second digit) is 
capable ot free motion in abduction and adduction. 

In the Cynomorpka, and even in the so-called " tail-less' 



1 



(72 THE ANATOSTY OF VEETEBRATED AKIMAL8, 

genuB, /nuiM, proper caudal musclea are present. In the limln 
there is a levator clavievla which paaaea from tte transvaiee 
pri>ceaa of the atlas to the acromion ; a doraO'epitrochlearU. 
eonaiating of a muaoular hundle detached from the laiUiimi 
doTsi near its inaeHioit, and pasaing to the distal and inna 
end of thehumeruB, or even further down; a scansoriuc, fcon 
the ventral edge of the ilium to the great trochanter, whid 
sometimes becomea confounded with the glidmua minimtw ,- » 
special abdactor assia meiaearpi qVMiti ; and a peronaniM qwnA 
digiii, arieiag from the fibula, between the peivnupus langu 
and brevis. passing behind the external maUeolua, and send- 
ing its tendon to the extensor aheath of the 6fth digit. 

The extensor primi intemodii poUicig and the peronam 
ieriiug are absent in this, as in the preceding group. 

The Weeps /emoi-H ueually posBessea only an ischial heaiL 
and the sofetw arisea only from the fibula. 'Fhejkmor brvA 
digitorum arisea partly from the tendon of the planlarii. 
where this paaaes over the pulley on the posterior surface 
of the calcaneal process to become continnona -with tie 
plantar fascia, and partly from the tendons of the long 
dexor. The tramruereae pedU is aauatly fully developedi 
but has only two heads of origin from the distal ende 
of the second and third metatarsals. The interosaei pedU 
are just visible on the dorsal aspect of the foot, bat none 
ai-e, properly speaking, dorsal. None of them are penni- 
form muaclea ariaing from adjacent aides of the metatarBsl 
bonea ; but they are attached, in paii'a, to the plantar and 
lateral aspects of the metatarsal bonea of the digits to which 
they iippertuin. Tfiey are inserted into the sesamoid 1xiiis& 
of which each digit baa two, and into the baaea of the ^mi- 
ma! phalanges, and give off no distinct tendona to tha 
eitenaor aheaths. Additional muaclea may arise over the 
proximal ends of the metatarsal bones, and pass to the 
three fibular digita. 

The iiiterosaei nianiia are very similar to those of Man, 
being divided into a dorsal and a palmar aet, and sending 
alips to the extenaor aheaths of the digits, without that 
complete subdivision which is seen in the Aaihropataorgha. 



THE DKNTITIOH OF THE CTHOMOKPHA. 473 



B There is a, complete double eet of esteneors in tlie foor J 
ptQuiir digits o£ the manus, the etienaor mmimi digUi giving I 
a tendon to the fourth digit, and the extenaor indieit o 
the third digit. The exteaiar oasia inetacarpi polliMi gi 
distinct slip to the trapezium, and thns preciBelj eorre^ I 
eponds with the tibialis anticim, which has two tendona, onft ■ 
for the ento-ouneiform, and one for the metataraal of the I 
hallui. The Jkasor digitorwm, profandua and jfeaKT l/Mgui J 
pollide tare represented by one muscle, a olip from the ulnur I 
side of the tendon of which uBuaUj goes to the poilei^ 

The tendons of the fiexor peiforatis tUgiiomm xadjtexor 
hallvt^ unite to form the deep flexor tendons of the pedal 1 
digits in very vaiiable proportions. The/e» 
is very generally present. 

The anterior upper premolar has its outer cusp peculiarly I 
modified and sharpened. The anterior lower premolar haa i 
the anterior margin of its crown prolonged and cutting, so 
that it works, like a seisaor-blade, against the posterior edge 
of the upper canine. In the upper jaw, the premolars have 
tbi-ee roots; in the lower, two. The molars in both jaws 
have four cusps connected by two transverse ridges. Some- 
times there is " heel " behind the posterior ridge of the laat 
lower molar. 

The formula of the mill: dentition is d.i. — d.a. -^^ d-m. 
j-j = 20; and the anterior milk mobr resembles the per- I 
manent premolars, while the posterior is like a permalient 
molar. 

The permanent canines make their appearance before or, 
at latest, contemporaneously with, the hindermost molar in I 
both jaws. They are large and long, and are separated, by 
a well-marked diastema, from the outer incisor above, and 
from the fii-st premolar below. 

The Cynofnorpha very generally possess cheek-pouches, 
which aorre as pockets for the temporary stowage of food. ] 
The stomach is usually simple, with a globtdar caj^afi ] 
extremity and an elongated pyloric portion ; but, in Senrno- J 
piihecue and CoIoIhu, the stomaek is divided into three oonb^ 



474 THE ANATOMT OF VBSTEBRATED 

pajtments, the middle of whicL is sacculated. A gnwit 1 
with raised edges leads from the cardiac end id tb« gdk I 
to tlie middle oompartment, i 

The ccEcmn, though distinct, is relatively small, and ta 1 
BO vermifonn appendage, I 

The liver varies much in the degree of its Huhlitsa ' 
into lol)es, being least divided in the SemnopWteci, anil not 
in the Baboons, The innominate' artery genetallj gim 
origin to both carotids, as well as to the right anbclaiift 
the left Hnbclavian arising directly from the iirch of lit] 

When laryngeal air 8at;aaredeveloped, they are not fomJ 
by dilatations of the lateral ventricles of the laiynx; Iwt» 
single sac. with a median aperture, ie formed in llie thjn- 
tyoidean space immediately beneiith the epiglottis. Tta 
median air sac is very large, extending down over thefnH 
of the neck, and sending prooeeses into the axills, 
Semnopitheci and Cyaocepjiali. The right lung ia vsmSj 
Eour-lobed, the left two-lobed. i 

The kidney has only a single papilla. I 

The posterior lohea of the cerebrum project beyond tlv i 
cerebellum in all the C^iumiorpfta; they are shortest in til i 
Senmopifftod, and longest in the Cynotxphali. The pris- 
cipal sulci and gyri which are found in the human bwio 
are always indicated ; but the estemal perpendicubir fissnn 
is strongly marked. The posterior comu of the lateral nfr 
tricle is large, and there is a strongly- marked hijapoctHojiK 

There ie usually, if not always, a hone in the penis, whid 
is provided with two special retractor muscles. The feraakt 
are subject to a periodical turgesc^snce of the sexual orgaii& 
sometimes accompanied by hemorrhage, and comparable to 
menstruation. The placenta is often bilobed. 

6. The Anthropoawtrp'ha differ from the Cymmunpha in the 
following characters : They are especially arboreal animals, 
which hahitnally assume a semi-erect posture, supportinf 
the weight of the fore part of the body upon the ends of 
the fingers or, more usually, upon the knuckles. There is 



THE ANTHSOPOMORPHA. 475 

no tail. The thigh and the leg are, respectively, shorter than 
the arm and the fore arm. The dorsolumbar vertebrae are 
seventeen or eighteen in number, and their spines are not 
inclined towards a common point. They devdop no inter- 
locking mammillary and accessory processes. The sacrum 
contains more than three ankylosed vertebrae. The thorax 
is rather broad than laterally compressed, and the sternum 
is flattened from before backwards, and wide. The axis of 
the head of the humerus is directed more inwards than 
backwards, and the upper part of the shaft is not bent as 
in the Cynomorpha. The radius is capable of complete 
pronation and supination. 

The relative proportions of the incisor teeth are the same 
as in Man ; that is to say, the inner upper incisors and the 
outer lower incisors are larger than the others. The crowns 
of the upper and lower molars have the same patterns as 
those of Man. 

The caudal muscles are small or absent. When the pollex 
has a flexor tendon, that tendon is not a sHp given off from 
one common to the flexor poUids and fleocor perforans, as in 
the Cynomorpha, The plantaris does not pass over a pulley 
furnished by the calcaneal process, as in the Cynomorpha; 
and the flexor hrems has an origin from that process. The 
peroncBVs quinti digiti has not been observed. 

There are three well-marked genera oi Anthropomorpha — 
Hylobatea, Pitheciis, and Troglodytes; and perhaps a fourth. 
Gorilla, may be advantageously separated from the last- 
named. 

Pithecus, the Orang, has the smallest distributional area, 
being confined to the islands of Borneo and Sumatra ; Hy- 
lohates, the Gibbons, of which there are several species, is 
found over a considerable area of Eastern Asia and the 
islands of the Malay Archipelago. The Chimpanzee and 
Gorilla are met with only in the intertropical parts of West 
Africa. 

The Gibbons are those Ardhropomorpha which are most 
nearly allied to the Cynomorpha. They possess ischial cal- 
losities, and the nails of the poUex and hallux, only, are 






476 THE ANATOMY OF VEKTEBKATED AN: 

broad and flat. The arms are so long that the points if 
the fingera readily touch the ground when the aiiiinul ataali 
upright, aa it very i-eadilj and commonly does. Tbi 
Gibbona also run with great ewiftneaa, putting the sole ui 
the foot flat on the ground and balancing themeelTeB wili 
their long anna. Neverthelesa, they are CBBentially arboial 
animala, leaping from hough to bough of the trees ia tk 
foreafa which they frequent with marvellous force iti 
preciaion. Tlie manua ia longer thim the pes, and the ante 
brachium. conaiderably longer than, the brachium. T4i 
Gibbons do not exceed three feet in height; their headi 
are amoll, and their bodiea and limba remarkably slendo'. 

None of the other Anthropomot'pha have callosities, ad 
the nails of all the digits are flattened. They are all heanff 
in make, with proportionally shorter limba and larger headi 
than the Gihhona, In the Oranga, which rarely attuD • 
stature of more than four feet and a half, tbe arms are raj 
long, their span, when outstretched, being nearly doubleUw 
height of the animal. The brachium and the antebrachinn 
are equal in length. The long and narrow pea ia loi^ 
than the equally-naiTow manna, and the sole cajinot b< 
placed flat upon the gronnd, but the animal rests apon d« 
outer edge of the foot when it aastmies the erect posture [ 
This poature, however, is quite unnatural, and the Orai^ I 
cannot run aa the Gibbona do, bnt swing tbemaelves sltrng 
upon their long arma. as it were upon crutches. 

The pollez and the hallux: are both short, tfa« latter i 
remarkably so^ and the hallux is not uncommonly devrndj 
of a. nail. The palmar and plantar aspects of the digib 
ai'e natuiTilly concave, and they cannot be completely 
straightened. 

The Chimpanzee attains a statui'e somewhat greater than 
that of the average Orang. The span of the arms ia aboat 
half as much again aa the height. The untelnuchiam is 
about as long as the brachium. The manus ia equal to, or 
a little longer than, the pes; and these pai-ts of the limbs 
ai-e not 80 elongated, or so em-ved, as the corresponding parts 
of the Orang. The sole can be readily phiced flat upon, th&r 



THE AMTHBOPOMOBFHA. 477 

pound, and the Chimpanzee easily stands or nms erect. 
■nt Ilia favourite attitude is leaning forward and supporting 
imaeli on the knuckles of the manua. Both the hallus and 
e polles are well dereloped and poaaeaa nails. 
The Gorilla exceeds five feet in height and may rea^ 
Ke feet six inches. The span is to the height as ahoat 
b;ee to two. The brachiuni ia mudh longer than the autei: 
rachium. The pea ia longer than the manna, and bo( 
re much broader than in the other Antkropoinorph 
oneeqnence of this circumstance and of the greater develi 
jnt of the heel, the erect poature ia easily maintained, bi 
e ordinaay attitude ia the same as that aasumed by 
Jhimpanzee. The hallux and the polles have well-dev*- 
oped nails. The baaal phalanges at the three middle 
iigits of the foot are bound together by the integument 

"With respect to the skeleton in the Anthroponiorpka, the 
Sibbons have the spinal coltmrn nearly straight, ^th 
b vei-y open vertebro -sacral angle. In tho Oranga tha 
vetebra form a curve, which is nearly as 
i forwards as in a new-bom child. In tho 
mpanzee the spinal column begina to exhibit the 
inrvatures which are characteristic of the adult human 
inbject ; and these are still mure marked in the Gorilla. 
The spinous process of the second cervical vertebra 
bifurcated in tho Chimpanzee, bnt this human cliaraci 
Boes not appear in the others. 

In tho Gibbons there ai-e usually eighteen dorsolnmbi 
vei-tebrffl; but in the other Anthropomorpha th 
ordinarily seventeen, as in Man, or may he reduced to 
sixteen. The Orang has the human number of twelve 
pairs of ribs ; but the Chimpanzee and Gflrilla have thirteen, 
and the Gibbona may poaaeaa fourteen paira of ribs. The 
thorax ia wide, and the atemum broad and flat. In the 
Orang it may osaify from a. double longitudinal aeriea of 
centrea, as sometimes happens in Man, 

In the Gibbona the tranaveras proceaaes of the last lumbar 
vertebra are not exceptionally broad, and do not unit* with 
the ilia, Bnt in both the Ghimpan2ee and Ckinlla they 



■ ifl ^^^ 




478 THE ANATOin OP VEBTEBBATED ANIMAIS. 

arc wide, aad become more or less closely connected wll 

, the ilia. Tbe last lumbar yeitebra may beeome anijIoaJ 

with the BaGram in tie Gorilla, All these conditions J 

the last lumbar vertebra are occasionallj met with in 

The Bacmin ia broad, and containa not fewer than fin 
ankyloeed vertebne, but ita length always eiceede it 
breadth (whereas its breadth is equal to, or exceeds, JB 
length, in Man}, and its anterior curTa,tiire is but aliglt 
The ahort eoccjs ia made up of not more than four o: 
vertebne. In the akull, the proper form of the brain-caat 
is alwaja more or less disgniaed in the adult males, b; & | 
development of cresta for mnacular attacbment, oro! tli»| 
orbita and tbe supraorbital ridgee. In tbe Gibbona ml 1 
Chimpanzees, the latter are large, but the sagittal crertii ) 
abaent, and tbe lajubdoidal smaD. In tbe Oraug, the bro* 1 
ridgea are amHll, ao that the true form of the forehead is 
better than in the other Apes, but the sagittal and lamb- f 
doidaJ. creats ore strong. In tbe old male Gorilla the aagitlil 
and lambdoidal creats, and the aupraorbital ridges, u 
alike enormoua. The frontal sinuses ore large, and extend 
into the brow ridgea both in the Gorilla and Chimpaimcv 
The jawB are largest in proportion to the braiii case 
Gorilla and the Orang ; smallest in some vaiieties of Chim- 
in all the Anihropomorpha the tranaverse ia much \t» 
than the longitudinal diameter of the craniaJ cavity, 
roofs of the orbits project into the frontal portion of the 
brain case, and diminish its capacity by causing its floor to 
slope from the middle line obliquely upwards and ontwuds. 
The occipital foramen is sitnated in the posterior third of 
the base of the akuU, and looks obliquely backwards 
downwarda. The frontala meet in the base of the skull 
over the ethmo-preaphenoidal suture in the Gibbons and ii 
the Gorilla, as in the Babuona ; but not in the Chimpanzee 
or the Orang, The alispbenoida unite suturallj with the 
parietals, as is the rule ui Man, in the Gibbons and (usually) 
in the Orangs ; but, in tbe Chimpanzee, the squamosal unites 
with the frontal and aeparatea the aliaphenoidfroin thepan» 



ta],iia happens, exceptionally, in. Man, Thenasal bonea a; 
flat andeailyankjlosed together, in the GihboiiB.Oraiiga, and . 
Chimpiunzees. In the Glurilla the nasal boneaare diHtinctlf J 
convex from side to side, and rise above the level of thetaae, | 
None of these Apes ha« a gpina naealis anterior ; and, onlj ii 
the Siamang, ia there a rudiment of the mental prominenca I 
in the mandible. The premasilio-masiUary suture persistB f 
beyond the completion of the second dentition in all but 
the Chimpanzee, in which it disappears liefore IJiat period. 
Tie epiotie region is never developed into a. distinct [ 
mastoid process; and there is itn ossified styloid pracesB | 
only occasionally in the Orangs. The palate is long and 1 
narrow, the alveolar margins being nearly paraUei, or even 
diverging anteriorly. The zygomatic arches are strong, 
■wide, and curved in two directions. 

The proportion of the length of the basi-craaial axis to 
that of the cerebral cavity, does not fall lower than the ratio I 
of 10 to 17 in any of the Aiithrop<mtor2>ha. 

The body of the hyoid approaches tlie form of that of J 
Man most neai-ly in the Orang. In the other genera it ia I 
more escavated posteriorly. 

The scapula of the Orang is most like that of Man, ea- 
pecially in the proportion of the supra- and infra-spinoua I 
f oasiE, in the proportional length of the anterior and the 1 
posterior borders, and in the angle made by the spine with ] 
the vertebral margin. In the other genera the posterioi 
border is longer in proportion than in Man, and the spine ] 
of the scapula cuta the vertebral margin more obliquely. 
After the Orang's, the scapula of the Gorilla comes nearest \ 
to that of Mnn. 

On the other hand, the long and straight clavicle of the | 
Orang is least like that of Man. 

The head of the humerus loses the backward inclination | 
which it has in the lower Apes, and becomes directed up- 
wards and inwards, as in Man, The radius and ulna a 
curved, and leave a wide interoaseons space. Thei'e e 
nice bones in the corpos in both Rylobatas and Pithecas, \ 
but mdy Kght in the Chimpanzee sjid Gorilla. In Bgio: 



480 THE ANATOMT OP TEHTKBKATED ASTMAIA. 

bates the articular surface presented by the traperiia 
for tlie poUex is almost globnlar. It is evenly 
the Chimpanzea ( but, in the Gorilla, it has the chajnctcm 
tically human saddle shape. The poU.cz is longest bbI 
strongest in proportion in Rylobaleg ; its length in prqw- 
tion to that of the manus being in H. eyndactylu* as thiet 
toseren. In the Gorilla, the pollexbas rather more tlianow 
third the length of the manua; in the Orang and Ctin- 
panzee it has about one-third the length of the manns. 

The pelvis differs but little from that of the Cynmiwr^ 
in Mylobaiee. In the other genei'a the pel' ' 
elongated. The antero-posterior diameter of the brimrf 
the pelvis greatly exceeds the transverse, the tuberosities i;! 
the ischia are strongly everted, and the pnbio aymphjas 
very long, the arch being oorreapondingly reduced; hO 
the ilia are wider and more concave forwards in the Chim- 
panzee, than in the Orang, and in the Gorilla than in either. 

In the female Chimpanzee, which is of about the 
size as the male, the dimensions of the basin of the pdri» 
and of its ontlets, are greater than in the male, thonghtlK 
general form and absolute length of the pelvis are the 
in the two sexes. The female Gorilla is much smaller 
the male, and the pelvis is shorter in proportion, but tfct 
intersciatic measurement of the outlet is absolntely u 
great as in the male, and the transverse diameter of du 
brim is nearly as great. As, at the eame time, the antero- 
posterior diameter is much shorter, the brim of the pelvis of 
the female is much more round. The female Orangs, alsc^ 
are smaller than the males. The basin of the pelvia if 
relatively, but not absolutely, larger in all its df 
and the brim rounder. 

The femur of the Orang has no round ligament, and 
differs in this respect from the same bone in the other An- 
tJa-opomorpka. The femur of the Gorilla i-esembles that of 
Man, most especially in the projection of the articular aurfaM 
of the inner condyle beyond the outer. 

The length of the whole foot to that of the tsrsna is. 
Sylobaki, aa tbirty-five to ten, and the proportioii ia 



THS FOOT IK THE ANTHHOPOMOKPHA. 48l | 

le in the Orang; in the Chimpanzee it ie aa twenty- 
r to ton ; and. in the Gorilla, about the Bome (twenty- 
e to ten in the epecimen meaBured). 
I The hallnx has not more than one-fonrth of the length 
[ the toot in the Oi'ang ; in the Gorilla less than five- 
Swelftha ; in the Chimpanzee and in Hjlobates a Kttle more. 
I la the Beaond digit of the pes of the Orang Eind the 
mpanzee, the phalanges, taken together, are longer than, 
3 nietatarBal bone of the digit; in the Gorilla, they 
Ibout equal in length to the metutarBitl. The calcaneal 
a longest, strongest, and broadest in the Gorilla. 
1 the aatragalus the articular surface for the tibia is 
roadeat in the Gorilla ; bnt, in this Ape, as in the others, it 
i inclined a little inwards when the foot is in its natural 
Bosition; and the aurface for the external malleolne 
Bbliclue, and looks upwards as well as outwards. 

~ "a a mistake, however, to suppose that the dispositiMii' 
of these aurfacea has anything to do with the more or lesM' 
marked tendency of the plantar surfape to turn inwards, 
and of the outer edge of the pea to be directed downwardSt 
which ia obseirable in all the Anthropomorpha. This 
tendency ia the result of the free articulation between the 
scaphoid and the cuboid, on the one hand, and the as- 
tragalus and the calcanenm on the other; tie consequence 
of which is that the diatal portion of the pea, with the first- 
mentioned bone, being palled by the Uhialia anUcag, easily 
rotates round its own aiia, upon the surface presented \^ . 
the aatragolus and calcaueum. This ready inveraion of UU' 
sole must as much facilitate cUmbing, as it must interfere 
with the steadiness of the foot in walking. 

The diatal anrfaco of the entocuneiform is much iaclinrf 
inwarda in aU the Anthropinnorpha, and ia convex from, sidft 
to aide, or aubcylindricaL The metataraal bone of thff 
hallux presents a correapouding articular concavity to this 
surface, and has a great range of motion in adduction and 
abduction. The inward inclination of the articular facet 
of the entocuneiform, and its consequent separation from 
the facet upun the meaocunetform for the second digit, ii 
2i 



it, is ^J 



482 THE ANATOMY OF TEBTEBKATED ANIMALS. 

greatest in tie Orang, in whicli the hallnx is habitnally 
directed at riglit angles to the long axis of the foot. Tlw 
distai phalanx of the hallux is not anfreqtientlj absentia 
the Orang, 

All the Anlhropomorplia poBaeas certain inaBcles wHd 
are not usually found in Man, though thej may occur u 
vuietiee in the human Bubject. These ore the levator 
claviculrE, the doreo-epilrochlearie, the sccmgorivs* and the 
aiiductor oesis metaeaTpi guimH iKgili, They are also dewiid 
of two mUBclea whicii are neaally present in Man — tbe «ft 
teneor pHmi internodiii pollieisf and the peronieuB tertiw. 
The former of these ia sometimes, and the latter frequentlj, 
wanting in the human subject. 

The flexor atceasorim appears to be regularly absent io 
Sylohates and Fithecus, and, in tbe majority of caaea, in tbe 
Chimpanzee. The tranxversus pedit seems to be absent in 
the Orang, but it is present in the other Anthropomxtrpba. 

Many muscles which esist both in these Apes and in M.n 
have different origins in the former. Thus, the aolaM 
has only a fibular head, and takes no origin' from tlw 
tibia. The flexor brevia digiloraia pedis never arissi 
altogether from the calcaneum, , but a large proportiofl 
of its fibres spring from the tendons of the deep flenm 
The calcaneal head furnishes the tendons for the second 
or the second and third, digits. The interoaseous muade 
which lies on the tibial side of the middle digit of the 
pes, usually arises from the fibular side of the Becond 
metatarsal as well as from the tibial side of its own meta- 
tarsal, and its origin lies on the dorsal side of thut of the 
fibular interoaaeous muacle of the second digit. Hence, of 
the so-called dorsal inieroseei (or inleroaBei which are Tisible 
on the dorsal aspect of tbe pas) two belong to the middle 
digit, and one, to the second and foarth digits respectively; 
which is the same arrangement as that which obtains in ^e 

> Not BCtnally deacribed in the Uacilla, anil nlnent in some CMm- 

t The former muscle is Eiid to be present by aeveml snatMiMB 
in llic Chimpanscc iinil other Ape^ ; liiit nl)at tlicy have taken ta It 

is the melacorpal divisiou of the rxlimior owii mBlnnarjii, 



THE MYOLOGY C 



The JlexoT polUeis is more or leas closely ponneeted 
fdik the flexor amrnMnia per/oj-ans, or with that part of the 

luBcle wliich goes to the index digit. The conuBction is 
ilighteat in Bylohateg, the origins of the two mueoles, only, 
Jeing united. It ia most ejctensiTe in the Orang, in wbioh 

> tendon goes to tKe potlex. The aame complete losi 
e fleaor poUids, as a thumb muscle, occasionally takes 
I in the Gorilla; but in this animal, as in the Ohimp&n- 

3, the rule appears to be, that the flexor pollieU nnit^ at 

) origin with part of the flescor perforans, and that the , 
Heaby fibres conrei^ to a common tendon which dividea into. ■ 
e for the poUex and the other for the index. lA il 
Wyhlates, the abort head of the bleeps brachii arises from tbe 
pectoralie major, and the adductor hallueie and trangversus 
pedis form but one muscle. 

Tbefleaor longwt halhtds takes an origin from the ex- 
ternal condyle of tbe femur in the Orang; and the pecfo- 
ralig major arises by throe ilistiuct slips. 

Some of the muscles in the Aatkropomorpka differ iif ^ 
their insertion, or in the extent to which they are sub- .J 
divided, from what is usual in tbe corresponding musclea a 
Man. Thus tbe ealensor oseis metaearpi poUicis ends ia ti 
distinct tendons; one for the trapezium., and tbe other t 
the base of the metacarpal bone of the poUex. That part 
of tbe tibialig anticug which goes to the metatarsal of t 
hallux is usually very distinct, and is sometimes r 
as a separate muscle, tbe abductor l/mgus hallucie. 

In the Gibbons and in the OraJig, there is a complete a 
of deep extensors for tbe four ulnar digits, the tendons ot 1 
the extensor indieis and extensor mmimi digiti subdividing I 
to supply the third and fourth digits. 

In the Gorilla and Chimpanzee each of these musclea have 
but a single tendon, as is the usual arrangement in Man. 

The interoasei of the band are each divided into two 
musclea with diatinct tendons — a, flexor brevis primi inter- 
Tiodii and an exteiisor brems tertii intemodii. The divii 
lesa obvioUB in the Orang than in tbe other Anthrope 
morpka. 



484 



THE ANATOMY OP VEETEBRATED 






'1 I 



In Hylobates; the tendon of the flexor peiforanspedU go* 
only to lie fifth digit, and is not directly connected witi 
that of the flexof lonyua hallvcie, which eupplies the otba 
four digits. In the Orang, also, the tendons of the tw) 
TOUBcles are separate ; but the flexor perforaTiM supplies ll* 
second and the fifth digits, and ■^a flexor haUucis the thirf 
and fourth. It gives no tendon to the hallux. In brtl 
the Ohimpanzee and the GoriUa, a very large tendon B 
given to the liallus hy thefleaor hallucU. and it also supplier 
the third and fourth digits. The tendon of flexor Uyajm 
diffUoniin ia but slightly connected with that of thefiaer 
hallueie, and its divisions go to the aeeond and fifth toM, 
In both the manna and the pes of Hylobates a uuBcle oc 
■which 18 not, at present, known in any other Mammal. 
arises from the second metacarpal or metatarsal bon«< iuA 
is inserted by a long tendon into the pre-asial side of the 
ungual phalanx of the second digit ; it may be termed " o^ 
dllctor tertii inttTKcrl/ii seewnd/t diifUi." 

The Orang, in like manner, Btands alone in possessiiiga 
small, but distinct opponens haUucU.* 

The volume of the brain, in the Orang and in the Ohin- 
twenty-seven cubic inches ; ot 
jf a normal human brain. Jr 
) near thirly-five cubic inohei. 
very much smaller ; and the 
Siamang. among these, is remarkable for the short poBtciior 
lobes of the cerebrum, which, in this authroponiorphona Ape. 
do not overlap the cerebellum, as they do in aJl the othras. 

The cerebral hemiapherea are higher in proportion to 
their length in the Orang than in the other J.n(/irc>poniorpia; 
but, iu aU, they are elongated and depressed, as contpaicd 
with those of Man. The frontal lobes taper off anteriorly. 
and their inferior surfacea are excavated from without 
downwards and inwards, in correspondence with the pro- 

* It muit be borne in mind tbat lbe»e BtalemenU rce)>ccting tlw 
myalngf of the ^nMnpumor/iAa are bsBpd upon my own diasecUoni 
(someflmes supplemented by (bose of Duvermoy and other WW- 
tomiats) dI' parlicalnr Bpecimpns. UodJeBs varieties vUl no doubt be 
met with by those who carry their iniiuirleB furtbcr. 



panzee, is about twenty- 
about half the 
the Gorilla, the volnn 
In the Gibbons the 



485 

[jection. of the upTi-ardly conveic roof a of tLa orbits inttri 
I cranial cavity. The posterior comn of the lateral I 
istricle is always well developed, and contains a, pro's 
inent kippoeampae minor and emineatia coUaleralu. AnJ 
BCipito-teioporal or "external perpendicular" snlcua iijS 
fclwaya present. It ia most nearly obliterated in the Orangs. ' 
"1 the gyri of the hnman brain are represented in the 
1 hemiapheres of the Chimpanzee ; bnt they are 
mpler and moro symmetrical, aad larger in proportion to 
e brain (See Figs. 21 and 22}. The fissure of Sylvius ia less 
oclined backwards, and that of Rolando is placed more 
Eorwards than in Man. The insula has simpler and fewer 
idiating suki, and is not completely hidden by the temporal 
lobe. Only the second, third, and fourth annectent gjri 
ttppear upon the surface. The first remains folded upoa 'J 
self, and gives rise to the oharacteristicftlly simian occipito- -I 
■temporal or external perpendicular sulcus. The occipito* 
parietal aulcns, on the inner face of the hemisphere, is 
much more nearly perpendicular than in the human brain. 
The corpus callosum is relatively smuller; the septum 
luoidum is very thick, and the pi-e-comniiBsoral fibres are I 
well developed. The vermis is small in proportion to thft 3 
lateral lobes of the cerebellum, and the flocculi are rela- 1 
tively small, and lie below the latter. I 

The whole cerebellum is larger ia proportion to tli^f 
cerebi-ai liembpberes; the latter being to the former, as'il 
81 to 1 in iHan, but as 5| to 1 in the Chimpanzee * Ths | 
nerves are larger in proportion to the brain than in Man. .1 
There are no corpora trapesoidea, such as exist in the lower I 
Mammals, and the cmpora albicaniia are doable. I 

In all the Avihroptyniorpha, the inner incisors are lai^er 
than the outer, in the upper jaw; smaller, in the lower jaw. 
There ia a diastema, though it is often but small in the 
female Chimpanzees, The canines are large and strong, 
and may be grooved longitudinally on their inner side^ 

• It must be recollected tliat the brains of young nnthropomorpho^H 
Apes, only, have been einniined. Perlmps this has to do with tl^H 
abaeooe ol' miaentt deporiU In Ihe pineal gluiii of tbe Ape«> ^^H 



48S THE ANATOMY OF VERTEBRATBD ASIMAI£. 

The premolars Lave three roots in tlie upper jaw, two 
lower. Tlie crowns of the niiddlo molars, above, have font 
cusps, and an oblique ridge which extends from the astoo- 
extemal to the postero-intamal cnep ; and those of the mi Jdic 
molar, below, have fire cusps, as in Man. The crown of ttt 
anterior premolar in the lower jaw is pointed, and hu ■ 
long, sharp, ohliqne anterior edge as in tbe Cynomorpha. 

In the Gibbonfl, the permanent canine emerges crrntoB- 
poraueously with, or before, the last molar ; but, in the olliB 
AidhroponiorpliO, the last permanent canine is cut, ordinarilj, 
only after the appearance of tie last molar. 

In the Orang the circumvallate papillsB of the tongue lu 
arrfinged in a Vi as in Man. In the Ciiimpanzee they in 
diajtoaed like a T, with the top turned forwards, "nit I 
Chimpanzee and the Siamang hare an uvula, but tbe Orang I 
has none. The stomach of the Chimpanaee is very like list I 
I if Man; but in the Orang the organ is more elongated, 
with a round cardiac and more tubular pyloric portion. 
An appendix venrnfifrmin is foimd in the cmcum of all tavx 
genera. In the Chimpanzee and Gorilla, the origin of tJit 
great arteries from the arch of the aorta takes place as in 
Man. In the Orang, they are Bometimea disposed s 
Man; while in other apeeimons the left carotid comes off 
from the innominata, and only the subclavian of the left 
side arises directly from the aorta. In Sylobaleg, the latter 
arrangement appeal's to obtain. 

The kidney has only a single papilla in SylobaUt and 
Piihemis. 

Only one species of HyUibatee, namely, tbe Situnang. ib 
known to possess a laryngeal sac. This is globular, and 
eommiuiicates by two apertures, situated in the thyrohyoid 
membrane, with tbe larynx. In the Orang, Chinipanzee, 
and Grorilla, enormous air sacs result from the dilatation 
of the latei'^ ventricles of the iarynjt. These dilataticms 
extend down, in front of tbe throat, on to the thorax and 
even into the axilla, and sometimes open into one another 
in the middle line. 

In the adult m^e Chimpanzee the penis is nma.!! anA 



EELATIOBB C 



TO MAS. 487 



Ifflender, and terminateB in a narrow 
e testes are yery large, and the ci 
le tunica vi^nalia and the peritoneiun is completely closed, 
e glans penia of the Gorilla ia button- shaped. In the 
)rang it is cylindrical, and the teat«a are situated close to the 
piguinal canal, vhioli has been f ouncl open on one side, and 
j^oeed on the other. An os penis is developed in the males. 
' The fem&leB have the clitoria large, and the uterus, which 
B undivided into comua, resembles that of the imman aub- 
H!ject. The placenta of a Chimpanzee f tfitua, 111 inciiea long, . 
a simple, ivtunded, 3] inchea in diameter, and 0'6 inch ■ 
thick in the centre. The umbilical cord was inserted near i 
one of its edges. 

The proportions of the limbs to one another and to the 
body do not aenaibly change after birtb; but the body, 
limba and jawa, enlarge to a much greater extent tban the 
brain- case. 

The amount of variation in tlie characters of tlie akn^fl 

among the Chimpanzees, Gorillas, and Oranga, ia exceedfl 

inglj remarkable, especially if taken in connection nio^l 

their very limited areas of diatrihution. ^ 

Of the four genera of the AnthropmnoTpha, the Gibbons^ 

are obviously moat remote from Man, and nearcat to the J 

Cyni^iUtecmi. ■ 

The Oranga come nearest to Man in the number of thfl' J 

riba, the form of the cerebral hemispberea, the diminution J 

of the ocoipito-temporal sulcus of the brain, and the OBsified 1 

styloid proceee ; but tliey differ from him much more nidely J 

I in other respeeta, and especially in the limba, than the Go- | 

idlla and the Chimpanzee do. I 

The Chimpanzee approaches Man most closely in the ' 

, efaaracter of its cranium, its dentition, and the proportional 

[ size of the anna. 

I The Gorilla, on the other band, is more Man-like in the 
l.pToportione of the leg to the body, and of the foot to the 
Kband; further, in the aize of the heel, the curvature of the 1 
hpine, the form of the petvin, and the afaaolute capacity of 1 



■iSS THE ANATOMY OF VEKTBBKA.TED AUlMALfi, 

c. The AnlhropidiE are repreaeated by the aingle genu I 
and species, Utaa, and they are diBtiugoislied from lb 
Simiadce, and especiallj the Antliropcmiorpha, by the folln* ' 
ing charaoters : 

In progresHion on the gronnd, the erect posture is 
easiest, and no assistance is given by the arma, which 
ehorter than the leg's. After birth, the proportions of tb 
body alter in consequence of the legs gi-owing faster ibn 
the rest of the body. In consequence, the middle point ol 
the height of the body — which, at birth, is situated about tlie 
umbilieUH — becomes gradually lower, until, in the adult 
male, it ia as low as the symiphyns pubig. 

In the man\i8, the polles is strong and long, reachiitgtn 
the middle of the basal phalanx of the index digit. Intb 
pes, the tarsus takes up half the length of the foot; the 
calcaneal proceas is long, and expanded posteriorly, Tto 
hallux has half the length of the foot, and is nearly u 
long as the second digit ; and its mobility in adduction and 
abduction ia slight, compared with that of the hallux ot 
the other Primaieg. 

Hair ia more abundmit upon the crown of the head; 
and, usually, in the aiilhe, the pubic region, and the front 
part of the thorax, than elsewhere. 

Tn the new-boru infant the whole dorao-lnmbar region oT 
the spine is concave forwards, and the rei-tebro-saoral an- 
gulation is slight ; but, in the adult, the apinaJ column ia 
oonottve forwards in the thonuiio, aiid convex forwards in 
the lumbar, region, mainly in consequence of the diapo- 
aitioa of the elastic ligaments which connect the fa«ee and 
the arches of the vertebne. There ia a strongly -marked 
vertebro-sacral angulation. Normally, there axe twelve 
dorsal, five lumbar, five sacral, and four coccygeal vertebrW, 
and the trajwverae processes of the last lumbar vertebra 
are not expanded or dii'ectly connected with the il'i» ; but, 
in these respects, variations occur. 

The spinous processes of the middle cervical vertebne 
are much shorter thaa the seventh, and are usually bifnr- 
cafed. Tlie treaAt^i ot tte BacuMm. \a ^taSsn tlum its 



THE ANTHEOPID*;. 

lengtii. In the etull, the occipital oondjlea lie withiii the 
middle fifth of the base, and the occipital foramen looks 
downwards, and eitiier a little forwards or but slightly back- 
■wards. Neith nr 'lagittal nor lambdoidal cvesta are developed, 
but the nmrtoid proceBsea are diatinct, and generally con- 
apicuons. The aupmorhital ridges aj'e never ao largely 
developed aa in some of the Antliropmnorpha. The orbita, 
ajid the jaws are relatively smaller, and eitu^ted leas ia. 
front of, and more below, the fore-part of the brain-eaae. A.' 
fpina ntualls anterior is almost always present ;* and, in tlie 
profile view of the face, the nasal bones project more beyond 
the level of the ascending proceas of the masilla than they 
do in any Ape. The palate is broader and its contour more 
ai-ched thoji in any of the Anthropmiurrpha, Its poaterior 
margin is ordinarily produced in the middle line into a. 
spina naeoiis ponierior, xad the palato-nioxiUary sntiire ia 
dii-ected transversely. 

The distance between the zygomata is either leas than the 
gresiteat tranHverse diameter of the calvai'ia, or exceeds it 
but little. The malar, is deeper than, the eqnamosal, portion 
of the zygoma, and the upper edge of the zygoma ia hat 
little curved. 

The post-gltnoidal process of the equamoBal ia small., 
while the auditory foramen is vertically elongated; itqi 
anterior wall being more or lesa flattened. 

The Lnterorbital apace occupies about one-f ourtli of the 
interval between the outer wali of the orbits. 

The planes of the orbital snrfaoes of the ethmoid bones 
(ossa plana) are nearly parallel with one another. 

The symphysis of the lower jaw has a mental promi- 
nence. The length of the cerebral cavity is more than 
tjpince that of the basi-cranial aus. 

P After bii-th, no ti-ace of the premaiillo-niaxillary autur*' 
a upon the face, though it may persiat in the palate< 



I 



I 



' The only human skull in w 
of the exiBlotiop iif the anterior 
wliinh, soma yEiCi ago, I preaoat' 
of Suigeuim. 



D able to And nn 
lliat uf an Aueli 
im of the Itoyal Cutlets I 



OP VEaTBBEATED ANrMAia. 

The naeal Biiture UHUally pei'aistB, and the direction ol tb 
fronto-ntwul Buture is nearlj triinsverse. 

The cranio-fadal angle* dooe not esoeed 120°, and in li 
higlier races of manliiiid does not go mncli beyond 9ft'. 

The supra-orbital plates of the frontal bonea project bw 
little into the frontal region of the brain-cttse, and thejiii 
almost horizontal. inBtead of being Bti-ongly inclined nj- 
wardB and outwardB, as they are in the Anthropomoffii. 
The cribriform plate is long and wide, and the erigta jaiiiii 
ttHUfllly prominent. The capacity of the brain-caae oil 
healthy adult is inTariably more than forty cubic inche*. 
and may riae to more than a hundred cubic inches. 

The scapula ia broad in proportion to ita length, and 
its spine cuts ita vertebral edge nearly at right anglct 
The ilia are very broad ; their inner faces present a weD- 
marked concavity, and their crests an S-ahaped corvatnit, 
A line drawn from tke centre of the axticnlar surface rf I 
the sacmm. to the centre of the acetabulum makes nL-ailj I 
a right angle with the chord of the arc offered by the I 
anterior face of the aacrum. In al! the AiitJirojumiorfko, I 
this angle ia much more open. I 

The tuberosities of the ischia are hardly everted. The 
aymphysia pubia is comparatively short, and the subpuWe 
arch well marked. The width of the whole pelvis, from 
one iliac creat to the other, ia greater than its height, whitdi 
is the reverse of what obtains in the Apea. The transverse 
diameter of the brim is usnally not eiceeded by the antelO' 
poaterior diameter, though the contrary proportion oc 
sionally obtains. The female pelvis is more spacious, a 
hOB a wider subpubic arch than the male. 

The proximal ai-ticular surfiico of the asti'agalus look* 
almost directly upwards, and hardly at all inwards, whm 
the sole is dat upon the ground ; and the lateral facets an 
more nearly at right angles to this sui-foce than in e 
Ape. The inner and outer maDeoli are stronger ( 
more downwardly produced. The calcaneal process U 
thick, strong, enlarged at its hinder end, and not inCDrved 

* See p. i'JO for Uuj eip Uaatioo of ILia tana. , 



THE FOOT IN MAN. 491 

inf eriorly, but produced into two tuberosities on wbicb the 
heel rests. The form and disposition of the astragalar, 
navicular, and calcaneo-cuboid articulations are such that 
the distal moiety of the tarsus is capable of only a slight 
rotatory motion upon the proximal portion. 

The distal articular surface of the ento-cuneiform bone 
is very nearly flat, though it has a slight convexity from 
side to side, and is irregularly concavo-convex, from above 
downwards. The comparatively slight mobility of the 
metatarsal bone of the hallux arises partly from this circum- 
stance, partly from the fact that the proximal articular 
surfaces of the four outer metatarsal bones are not 
perpendicular to the axes of those bones, but are ob- 
liquely truncated, from the tibial side, backwards, to the 
fibular side. Hence the four outer metatarsal bones, instead 
of diverging widely from the hallux as they would do 
if their axes were perpendicular to the distal facets of the 
meso- and ento-cuneiform and cuboid bones, take a direc- 
tion more nearly parallel with the metatarsal of the hallux, 
and the base of the second metatarsal, as it were, blocks the 
latter, in adduction. The hallux thus loses most of its 
prehensile functions ; but, in exchange, it plays an important 
part in supporting the weight of the body, which, in the 
erect position, falls on three parts of the pes; namely, 
the heel, the outer edge, and the integumentary pad which 
stretches beneath the metatarso-phalangeal articulations, 
from the hallux to the fifth digit. 

In the infant, the sole naturally turns inwards, and the 
digits (especially the hallux) retain much of their mobility. 

The only muscles which exist in Man, but have not yet 
been 'found in any Ape, are the extensor pri/mi intemodi 
pollids and the peronceiis tertius. 

The only peculiarities in the origin of muscles which 
ordinarily obtain in Man, and have not yet been found in 
the Apes, are — ^the complete separation of the flexor poUicis 
longua from the flsxor digitorum perforana; the presence of a 
tibial, as well as of a fibular, origin of the soleua; the 
origin of all four heads of the flexor brevis digitorum pedis 



482 THE ASATOlffY OF 



from the calcaneum; the origin of the fibnLix inierottn 
of the second digit of the pes fi-om the middle luetaiarsil 
on the dorsal side of the tibial interosseus of the midSk 
digit. The result of the laat-mentioned arrangemsat ii 
that the second digit of tie pea has two " dorsal " interosauL 
like the third digit of themanus. In the Apes the inleroaci 
of the second digit are generally aminged in the same wi^ 
in both manus and pes. 

The tanddna of the^eMJ" hallucig ionyus a.nA Jlemor di^ 
forum jierforans are usuitlly more closely connected in tin 
aole o£ the foot in Man, than in the Anlhropoiiiorpha, But 
it ia to be noted that all the apparently distinctiye poco- 1 
liaritiea of the myology of tlie Antkrop<miiOrp/ia are to b( I 
met with, occasionally, as varieties in Ma-n , I 

In the brain of Man, the only distinotiTe features, apart I 
from its abaolttte eize (55 to 115 cubic inche8>, are tif I 
filling.up of the occipito-temporal fiasure; tlie greatw 
compleritj and leas aymmetry of the other sulci and gyri; 
the leas excavation of the orbital face of the £i-ontal lobe; 
and the larger size of the cerebral hem-iapherea, as com- 
pared with lie cerebellttin and the cerebral nerrea. 

There is no diastema, though the summita of the ceniaes 
project, slightly, beyond the level of the other teeth. The 
premolars have not more than two roots, and the anterior 
edge of the crown of the anterior lower premolat 
prolonged and sharp. The permanent canine tooth emeiges 
before the aecond molar. 

The penis is devoid of a. bone (though a priamatio carti- 
laginous body has occasionally been found in the centrt! of 
the glans), and ita glana has a different ahape from that oi 
any of the Aitthrropomorplia, The vnlva looks downii^rda 
and forwards, and the clitoris is comparatively si 

The changea in the propoitions of the different parts <4 
the body, at different periods of intra- and esti-a-aterine 
life, are very remarkable. In a fcetus an inch and a half 
long, from the vertex to the heel, the head takes up from 
one-third to one-fourth of the entire length. The arms and 
l^a are of aboat the same length, and are shorter than tA* 



THE LAWS OP GROWTH IN MAN, 493 

spine. The fore arm is about as long as the upper arm, 
and the leg as the thigh. The manus and pes are very 
similar in size and form ; and neither pollex, nor hallux, are 
so different from the other digits as at later periods. In a 
foetus rather more than five inches high, the head occupies 
a fourth of the entire height ; the arms are longer than the 
spine by one- sixth of their whole length, and are a little 
longer than the legs. The fore arm is about as long as the 
upper arm, and the thigh is a little longer than the leg. 
The manus and pes are about equal in length. In a foetus 
eight and a half inches high, the head measures less than a 
fourth of the whole height ; the arms are longer than the 
spine by a fourth of their whole length, and they are longer 
than the legs. The extremities of the digits reach down 
to the knee when the body is erect. 

At full term, the height of the head of the human foetus 
is rather less than a fourth that of the whole body, and the 
legs are longer than the arms. The arm is longer than the 
fore arm, and the thigh than the leg. The hands and 
the feet are still about equal in length. 

Thus it would appear that, while the head grows more 
slowly than the rest of the body, throughout the period of 
gestation, after the embiyo has attained more than two 
inches in length; the arms grow proportionally quicker 
than the body and legs, in the middle of gestation, when 
the proportions most nearly resemble those of the Anthro- 
pomorplia. In the latter part of the period of gestation the 
legs gain on the anns, and the proximal segments of the 
limbs on the distal ones. After birth these changes are con- 
tinued. The adult has, on the average, three and a half 
times the height of the new-bom child, and his arms are 
elongated in the same proportion. But the head is only 
twice as large, while the legs of the adult are five times as 
long as those of the child. At all ages after birth, the 
distance between the extremities of the digits of the out- 
stretched arms is equal to the height in average Europeans. 

Sexual differences, independent of the genitalia, are per- 
ceptible at birth ; and the female infant is, as a rule, slightly 



4&4i THE ANATOMY OF YEBTEBSATED AKOCAIiS. 

smaller than tlie male. These differences become moie 
marked at, and subsequent to, puberty ; and are seen in the 
smaller stature of the female, the larger size of the head 
in proportion to the stature, the shorter thorax, the longCT 
abdomen, and the shorter legs ; so that the middle point of 
the stature of the female is nearer the umbilicus than in 
the male. The hips are wider in proportion to the shoul- 
ders, whence the femora are more oblique. The ridges and 
muscular processes of all the bones are less marked, and 
the frontal contour of the skull is more sharply angulated. 
When the peculiarities of the female sex are not connected 
with reproduction, they may be said to be infantile. 

The different persistent modifications or "races " of man- 
kind present a very considerable amount of variation in their 
anatomical characteristics. The colour of the skin yaries 
from a very pale reddish brown — of the so-called *• white " 
races — ^through all shades of yellow and red browns, to olive 
and chocolate, which may be so dark as to look black. 

The hair differs much in its character, having sometimes 
a circular, sometimes an oval or flattened transverse section, 
and presenting all varieties, from extreme length and 
straightness to short, crisp wool. 

The hair on the scalp is longer than that elsewhere ; and 
it is very often, but not always, longer in the female. Hair 
upon the face and body is scanty in most races, and almost 
absent, except in the eyebrows, in some ; but in others it 
becomes greatly developed over the lips, chin, and sides of 
the face, on the thorax, abdomen, and pubes, in the axiUae, 
and sometimes, though more rarely, upon the rest of the 
body and limbs. When hair is developed upon the limhs 
the points of the hairs of the ann and fore arm slope 
towards the elbow, and those of the leg and thigh away 
from the knee, as in the Antliropomorplia. 

Enormous accumulations of fat take place upon the but- 
tocks of the Bosjesmen, especially in the females ; and the 
nymphsB of these and some other Negroid tribes become 
greatly elongated. 
It appears that in some of the lower races, e.gr., Negroes 



r 



(OE OF TAKIATION IS ANTHBOPIDS. 495 . 

ajii3 Auatrolians, the fore >irm and haiid, aai the foot and leg, I 
aa^ often lunger in proportion than in Europeans. Promnc* 1 
-v?eai-ing shoes, the hallux is much more moveahle in these I 
"races, and the foot is commonly employed for prehension. I 
There is no proof of what is so oommonlj asserted, thai 1 
■fche heel is longer, in pi-oportion to the foot, in Negroea. I 
The Bpinea of the middle cervical vertebns sometimes I 
cea^e, more or less completely, to he bifurcated in the lower I 
xaoes. Thirteen pair of riha are aometimea present, and j 
occasionally there is a sixth lumhar rert-ebra. There may be I 
one more sacral vertebra than the normal number ; and a, I 
modification of the last lumbar, ao that it resembles a I 
sacral vertebra, and becomes connected with the ilia, seems 
to be more common in Austrulians and Bushmen than 
in other stocka. 

In the lower races, the male pelvis is less in many of its 
dimensions, and seems to differ more from the female, 
QspeciaUy in the tendency to equality of the transverse and J 
antero-poatci'ior diameters of the brim, and the narrowness I 
of the intersciafcic diameter, than in the higher races. This is ■ I 
particnlarly obvious among the Austrahans. The antero- I 
posterior diameter of the brim of the pelvis is occiisionally I 
greater than the transverse, -and this variety would seem I 
to be commoner among the Bnahwomen of South Africa j 
than elsewhere. 

But it is in the skull that the difierent races of mankind I 
pi-esent the most striking oateological differences. The , 
pi-oportions of the ant«ro -posterior and the traaaverse I 
dimensions of the brain-case vaiy eitrem.ely. Taking ' 
the antero-posterior diameter as 100, the transverse dia- 
meter varies from 98. or 99, to 62. The number whieh thus 
expi'esBeB the proportion of the tranaverse to the longitu- 
dinal diameter of the brain-case is called the eepIiaUe index. I 
Those people who possess crania with, a cephahc index of I 
80 and above are called hraehycepkali ; those with a lower I 
indes ai-e doHckoeepluilu The brain-case also varies greatly 1 
in its relative height. The proportion of the length of the I 
cerebral chaiober to the biuicraniul axis (aa lOOJ. uaj idau 



496 THE ANATOMY OP YEBTEBSATED AKIMAIiS. 

to 270 in the higher, and sink to 230 in the lower races ; 
and there are great diversities in the extent to which the 
cerebral cavity is rotated backwards or forwards upon this 
axis. The position and the aspect of the occipital foramen 
vary considerably, as does the plane of that part of the 
squama occipitis which lies above the superior semicircidar 
ridge. The supra-ciliary ridges vary greatly in their develop- 
ment, and in the extension of the frontal sinuses into them. 
They are nearly, or quite solid in many Australian skulls. 

In the size, form, and disposition of the facial bones 
the different races of mankind present great diversities. 
A line drawn from the anterior extremity of the pre- 
maxiUa to the anterior extremity of the basicranial axis, 
may be taken to represent the facial axiSf and the angle 
included between these two is the craniofacial angle. It 
varies with the extent to which the face Ues in front of, or 
below, the anterior end of the cranium, from less than 90° 
to 120°. When it is great, the face is prognathous ; when it 
is small, the face is orthognathov^. This is the fundamental 
condition of prognathism or orthognathism, A secondary 
condition is the form of the alveolar poi-tion of the upper 
jaw, which, so far as it is vertical, tends towards ortho- 
gnathism ; but, so far as it is oblique and produced, tends 
to prognathism. 

The arch formed by the teeth is, in the most orthogna- 
thous races, wide and evenly rounded ; while, in the most 
prognathous, it is prolonged, and its sides are nearly parallel. 
The teeth themselves are much larger, the roots of the pre- 
molars and molai's more distinct, and the hindermost molar 
not so small relatively to the others, in some of the lower 
races, notably the Australians. 

The mental prominence may project beyond the line of 
the vertical alveolar margin of the mandible, in the higher 
races, or it may be almost obsolete, and the alveolar margm 
may be greatly inclined forwards, in the lower. 

The different races of mankind are divisible into two 
primary divisions ; the Ulotrichi, with crisp or woolly hair, 
I the Leiotrichi, with smooth hair. 



r 



; ULOTEICIII AND THE LEIOTEICHI. 



497 I 

a. The colour of tlie Ulotrichi varies from yellow-brown J 
-to the daj'kest hae kuovm among men. The bair &iid eyea 1 
are normidlj dark, aad, with oolj a. few exceptiona (among 1 
the Andaman Islanders), they are dolichoe^hali. The Ne..J 
groes and Bushmen of ultra- Saharal Africa, and the Ne-fl 
gritoa of the Malay peninsula and archipelago, and of thttj 
Papuan islands, are the members of thia Negroid Htock. 

6. The Leiotrichi are dirisible into — 

1. The Aastralioid group, with dark skin, hair, and eyes, I 
wavy, black hair, and eminently long, prognathous, skuUs, ! 
with weU-developed brow ridges, who are found in Australia ) 
and in the Dekhan. The ancient Egyptians appear to n 

to have been a, modification of this race. 

2, The Mongoloid group, with, for the moat part, yellowish i 
brown, or reddish brown, skins and dark eyes, the hair being J 
long, black, and straight. Their skulls range between thev 
extivmea of dolichocephaly and those of brachycephaly. T 
These are the Mongol, Tibetan, Chinese, Polynesian.^ 
!Esquimaui and Am< 



3. The Xantkoch/roie group, with pale skins, blue eyea, andl 
abundant fair hair. Their skulls, like those of the MongO' 
Itiid group, range between the extremes of dolichocephaly 
and brachycephaly. The Slavonians, Teutons, Scandi- 
niLviauB. and the fair Celtic-speaking people are the chief 
repreaentatives of this division ; but they estendinto North 
Africa and Western Asia. 

4. The dark whites, or Mdanochroi; pale-complexioned 
people, with dark hair and eyes, and generally long, but 
sometimes broad, skulls. These are the Iberians and " black 
Celts" of Western Europe, and the dark-complesioned 
white people of the shores of the Mediterranean, Western 
Asia, and Persia. I am disposed to think that the Melon- 
ochroi are not a distinct group, but result from the 
of Australioida and Xanthochroi. 



4 




498 THE ANATOMY OF YEBTEBSATED ANIMALS. 

Fossil remains of Men or implements of Human manu- 
facture have hitherto been fonnd only in late Tertiary 
(Quaternary) deposits, and in caves, mingled with the re- 
mains of a.Tiimal8 which lived dnring the gla<)ial epoch. 



AtciPEKs: 



artilaginouB i 



Air aacs in birds, 317. 
Alimentaiy caniU, 86. 
Alligator Urrapnie, 19S. 
Amia. caudal extinnity of, 17. 
calva, Mprodnctivo organs 

Amphibia, general chacactoriatics, 
172. 

dsvelopmoit, 190. 

gronpB, 172. 

heart, 183. 

limba, 180. 

muscles, 47. 

reproduclive CFigsna, 189. 

respiialory orgaoB, 187. 

teeth, 182. 

AmphiBboenoida, 230. 

Ankle-joint o( sloths, 381. 

AnoplotheridiB, 876. 

Antebracliium, mnactea of, 61. 

Anthropidte. Sec Man. 

Ant^ropomorpha, Keneral ciiaiac- 
lerialics of, .176. 

oompariaonotjW 

diviaions, 47B. 

Aortic arches. Sit Arcbea, aortic^ 

Apes. Set Simiadn. 

AJcb, pflctoral, &4. 

pelyic,87. 

poctoiTii and pelvic, of ohe- 

iDQia, S06. 

pectoral and pelvic, of pie- 

Bioasuria, SO, 214. 

Arches, aortic, SI, 99- 

H number o^ belonging to 

L Bkall, 77. 

^ peclvral, and stemam, of a 

■ frog, 181, 



Arches, viacera!, skeletoni oi 
Arctopithecini (marmoseta), i 

ral characterutics of, 162. 

brain, 464. 

Uniba, 463. 

mnacleB, 464. 

skull, 46a 

teeth, 463. 

Tertetne, 468. ■ 

AnuadiUoB, goDeral characteiiilic* ] 

of, 338. ' 

ArtiodacCyhL non - r 

367. 

rumioaQtia, 877. 

Aacalabota, 226. 
Auatialians, pecaliaritlea of, 41 
Avea. Sec Biida. 
Axolotl (Siredon), 186. 
aordo arch of, 82. 



Bai.:S!ioidea, goneixl cbaractei 

istics of, 395. 
Baleen plates, or whalebone. 3! 
Bate. See Cheiroptera. 
Birds, general characl«ri 



— brain of MtUa^ris yn 

— classiScatioD, 272. 

— digits, 282, 287. 
-ear, 306. 

— heart, 312. 

— larynx and syrinx, 313. 
'"- '-S, 201, 206. 



8,316. 



n, SDO, 



Birds, peli-U, 233, 



veitebne, 27S. 

SetahoFovl. 
Beua, teeth o^ 422. 
Blood, circolaCian of, in frag, 1 

corpuMles, 119. 

Bloodancking tats, 450. 
Bones of cetaeea, 391. 



— fishes, 28, S6. 

— t^aleopilhecuB, 4E 

— hedBBliog, 443. 



the akull, 22, 23. 

See also Ob, Osbs. 
BoBJeBHien, fat of, 494. 
Brain of anthrppomorpha, 484. 



Canal, alimeataty, 8.. 

apinal. and cord, 69. J 

CanftU of Sceoson, 79. 
Camivora, general o: 

of, 912. 
DlaaBJficot.ion, 421. 



462. 
CatanMoi, chamcteiif 
CatB, teeth of, 422. 
" ial estremitieB of polvplana. 

nia, and aalmo, 17. 

■ vorlebne, Ifi. 
CerelirBl nerves, 71. 
Cetaceo, general cfaaracterisda 






B, S95. 



Chalk, ichchyoaauria ir 



in, 238, 



— divisions of, 69. 



— hedgehog, 447. 

— hotiiontal section, 60. 

— lemuridie, 4fl9. 

— longitudinal and vertical 



modifications of, 63. 

pift, 64-69. 

pike, 164. 

platyrthiai, 468. 

porpoiBea, 410. 

rabbit, 64-69, 440. 

Brain-cale. See Skull. 

Bmta, or Edentata. 5ee Edentata. 



Chama^li 
Cheiroptera, general 

istiCB of, 4I>4. 

digits, 34. 

position of limbs of bata, 83. 

Chelone midaa, carapace ot 200. 
- — ' Beetion of ekeletan of, 199. 
Chelonia, general cfaaractariHtah 1 

197. " 

divisions, 207. 

heart, 308. 

muscular Byatem, 

oi^nins of copulation,"? 

pcetotal and pelvic ansm 

206. 

plastron, 201. 

Bkull, 203-205. 

Chelydra, forefoot of, 32, 
Chimiera monBtroaa, soclion of 



CamelidiD or tylopoda, S 



pomorpha, 487, 
CorpuBclBB, blood, 99. 

lymph, 101. 

CorpuB callosam in man 



a witii antluv- 



' „... J 


SSftSeHi. 


Chelydia, toot, S2. ^^H 


By Stem, 18. 


Chimieia, Bkull, 128. ^^H 


C™nio-faoUIadB!e,490,<96. 




Crocodile, anterior thonul^^^H 


iu thoracic re«ion ot 15, 


TegiooTlS- ^^^1 


Crocodilia, 24i), 


pelvis and hind limb, sa^^^H 


dermal ■nnonr, 350, 


Eknll, 264. ~^^^l 


ear, 8U6. 


Cyclodue (latertiiia), aktJ^^^H 


KToapB. 258. 

Eeort,ail. 


^^^H 


Dromieiu, pelvis and hnJ^^H 


lunga, 316. 


limb, 260. ^^^^1 


pelvis uid hind limb, 2fiO. 


Dugong, heart, 3»0. ^^H 


— „,„d^l„o,p^Sl.. 


Elephant, ekeletot^ 439, ^^H 
Pish, viscenU arch, Sli. ^^H 


teeth, aie. 


FiEtDS, bnmui, priiKinl^^^^l 


yertBLrffi,260. 


vessels, 94. ^^^| 


Cms, mnaclea of, 51. 




Cutuneoiu muaele of hedgehog, 


fore litib, 292. H^^l 

leg, 295, m. ^^H 


pocpoiae, m. 


pelvis, kl. ^^M 




iaerum of chick, 278. .^^M 


D. 


scapula and coracoUB^^H 

289. -t-^^^m 


Dekk, horas of, 384. 


skull, 2R3. 




spur, 297. 


ass. 

Dental focmnlni. Sea Taeth. 


atemum, 281. 

Flying fox, skeleton, 468. 


Dentition. See Teeth. 


Frog, norvous flvBlem, 70. 
skull and braij), 178, 188. 




cochles, 82-84. 


sternum and pectoral 


egg, 3- 


arch, ISl. 


fowl, stages of, 6, 8, 13, iO. 


HoIoptychuB, 146. 


liui.b. 27. 


Konio, pteguatit ulenu, 4. 


Bkoll of B»he«, 21. 


Horse, carpus, S50. 


vascular syatem, 93-96. 


cervical vertebnc, 346. 


veruhmta, 3. 


femur, 352. 


DlAGBAMS :— 


fool, 845, 34S. 


Aocipenser, akull, Ul. 




Alligator lerrapine, 198. 


skeleton, 347. 


Amia, caudal extremity, 17. 


t«rsue,343. 


Ichthjoeaurui, 243, 244. 


orraoB, 144. 
Amphiojiiu luiceoUtiu, 117, 


Iguanodon, p^vis and bind 


limb. 2CU. 


118. 


Liunb, ftetal, head. 27. 


Aortic arches, 91. 


Uraprev, ekuil and brain, Vn, 


AxoloU, 18li. 


124,125. 


Bird and ILnatd, bndo, 302, 




303. 


Ijon, skolBloQ, 414. 


Cachalot, sIidII. 401. 


Uwirds, pectoral nroh and 


Catarrbine monkey, 462. 


sternum, 35, 3tl. 


Chelooe, alteletoD, aheU, 19'J, 


visceral arch, 85. 


m. 


Mamma!, Tisc«ntl uch, SS. 



502 INDEX. 1 


Di AO RAMB— eomifiiKd. 




Moukfish (»7KUi«i), pectorsl 


lemnrid», 45B. ^^^| 


membcr.as. 


man, 31, 488. ^^H 


skull, 130. 




Mudfl.h, skull, X68, 169. 


musolea of, 52. 1 


Oomg. digit, 63. 


rabbit, 437. 




- — - seal nnd turtle, 34, 426. 


Ostrich, skuU. 2R*. 


Dinotherium, 431. 


Os,skdBWn,a77. 


Dipnoi, 167. 


Pig, brain, S5, 67. 
Pifo, brain, 1G4. 


Dog, anatomy of, 415. 
— digits, /l6. 


ontline, 42. 




pectfltal arch and fore 

liiDb, 158. 


Drom«UB, pelvis »nd hind limb, 


260. 


aknil, 151. 152, 151,165. 


Dugong, heart of, 390. 


Plaice, skull, 29. 




PleaioHiurns, skaleton, 310. 




Polypterns, caudal ratramity, 


E. 


Pt«rl>dactylnB, skeleton, 267. 
Python, doia»l vectebm, 284 


Ear, 81. 


hones of whale, 397. 


skull, 236, 23B. 




Rabbit, hrain, 65, 67. 
fiattlBSnakB, skull, 340. 


See Hearmg, organfl of. 
andcharaclariBtic8ol,33l: 


vertebrata, lOS. 


esUnct,835. 




loricata 838. 


Salmo, i^Ddal extiemiCy, 17. 
Bflcretiuy bird, BktUI, 287. 


mutica, 336. 




Shark, aortic bulb, 132. 


of, 33a 


Sheep, stomach. 37fl. 


sqoamata, 837. 


Skat*, brai.1, 134. 


— teeth of, 330. 33,5. 


Spatularia. skull. HO, 




Stui««on, skull, 141. 




Tadpoles, 191. 




Torpedo, 68. 


Electrical organs, 67, 5S. 


TromatosauraB, skull, 179. 


Elephant, skeleton of, 429. 


Turtle, heart, 810- 


S«e Proboscidc*. 


plastron, 202. 




sktdl, 203. 204, 205. 


ment of, 5. 


Vertebrate brain, aectiona, 60, 


Encephalon, 59. 




Endoskeleton, segment of in tho- 


Wbale, skull. 396,097. 


racic region of a crocodile, IB. 






Didelphia, characteriaticB of, 323. 


EntomophagB, 335. 




^ stomach o?327. 


328. *- "^ 


Digits of anthroponiDrpha, 479, 




fossils of eiiuidffi in, 358, 


bat, Si, 4fi4, 468. 


859. 


birds, 297. 


foBsil rodenta of, 443. 


cmomoqiha, 473. 


Episkelfltal muscles, 46. 


iog, 416. 


Equide, fossil, 858. 



503 ^1 


k|uiilffi (horecs and aseaa), general 


Fowl, scapula and coracoid, 289. ^^^H 


charatCerieticB of, 3i3. 


-^ skuU, 283. ^H 


See Horse. 


sternum, 281. ^^H 




tibia and fibula, 29a, 296. ^^M 


■ iQ birds, hBhea, reptiles, and 


Frug, aortic arch o^ 92. ^^H 




-^brain, 188. .^H 


374. 


— cerebro-apinal and sympi^ -^^H 


. of replilia, 19S. 

Eye mnsclpB of aauropsiiln, 804. 


thelic nervona system, 7I>. ^^H 
piruulalion of blood, 186. ^^^H 




- — -larva, I9L. ^^M 




skull, 176. 176. ^^H 


F. 


— stemuu, and pectoral arche^,^™ 


'aue. bones of, 25. 




— of man, mS, 496. 


^^1 


ieial miisclea, 73. 
'eathers, 274. 


Galeofitubcub, general chanM- ^^^| 

teristics of, 450. ^^H 

Gsnoidci, exisling and fossil, 14S. ^^H 


'einiir of the horse, 85a 
5ns of fishes, 311, 40. 
EleheB, cki^tntud organa o^ 67. 


genera of, 137. ^^^^| 

Gibbons, 475. ^^^1 


groups in class, 115, 


GlTptodoD, peculiar ehaiaoter o£ .^^^| 

S40. ^^H 

Gorills, 477. ^^H 

Growth in man, law!! 0^ 493. ^^^H 


muSL-ular aystou, 48. 

laylikebonBB, 28. 

ekeleUn of Tieceial arches of 


osseous fish, 86. 




skull, 21, 30. 


^^H 






of,^ir 




■ Flatfishes {pleiironectida), 80. 


neryes^f,71. *^^^M 


Flying fox, skeleton of, 453. 






483. ^^^1 




Ilead and (nink, muaculai 8ysteiii..^^^^l 


principal veasels in, 94. 


_^H 




of spoim whale, 400. ^^H 


horae, 346, 349. 


Hearing, organs of, cases, 34. ^^H 


mim, 49U. 


in cetacem 410. ^^H 


Fossils in chRlk, S2S, 339, 349. 


bal, 455. ^^H 


— eocene sQat*, 328, 858, 8o9, 


■ 378,442. 


birds. ^^H 


L lias, 208, 349. 


crocodiles, 311. ^^^H 


I hiimML497. 


modifiealiona of, 97. ^^H 




porpoise, 4U7. ^^^H 


r 22B, 258, 265, 288, 328. 




■ miocena fonnadon, 358, 359, 


teleoslei, 181. ^^H 


383,365,375,876,886,388. 


turtle, 3U9, 310. ^^H 


Hedgehog, 442. ^^H 








(eristics of, 374. ^^^H 


_ 268, 361, 328. 




B 12,18,20. 


Horns of deer, dtc, 381. _ _ ^^^H 




■. polvis, 293. 


J^^H 



504 



INDEX. 



Horse, cervical vertebra, 346. 

femur, 352. 

forefoot and hindfoot, 345, 

349. 

limbs, 348. 

muscles, 353. 

ossa imiominata, 351. 

skeleton, 347. 

skull, 348. 

teeth, 344, 354* 

viscera, 356. 

Hyposkeletal muscles, 45. 
Hyracoidea^ characteristics 



432. 



of. 



I. 



IcHTHYOPsiDA, characteristics of, 

112. 
Ichthyosauria, 242. 

pectoral arch, 247. 

pelvis, 249. 

* skeleton, 244. 

skull, 245. 

vertebrae, 243. 

Impregnation of vertebrata, 3. 
Insectivora, characteristics of ,442. 



J. 

Jacobson, organs of, 79. 

K. 

KlONOCRANIA, 228. 

L. 

Lacertilta, 216, 

groups, 224. 

organs of copulation, 318, 

skull, 219. 

Lamb, development of, 27. 
Lamprey, optic nerves of, 71, 73. 

sections of skull, 122, 125, 

skull, 21, 

teeth, 87. 

Larva of frog, 191. 
Larynx, 103. 

platyrrhini, 467. 

sauropsida, 313. 

Leiotrichi, 497. 



Lemuridse, general characteristics 

of, 458. 

brain, 459. 

limbs, 458. 

organs of reprodaction, 460. 

skull, 459. 

teeth, 460, 461. 

Lepidosiren, aortic arch of, 92. 
Lepidosteus semiradiatiis, brain 

of, 138. 
Lias, chelonia in, 208. 

ichthyosauria in, 249. 

Limbs of amphibia, 180. 

birds, 291. 

camivora, 412. 

fishes, 38. 

galeopithecus, 460. 

hedgehog, 446. 

horse, 3^. 

hyrax, 433. 

lemuridae, 458. 

man, 488. 

marmoset, 468. 

muscular system of, 48. 

pig, 369. 

porpoise, 405. 

-^ — position of, 32. 

seal, 426. 

vertebrated animals, 30. 

Lion, skeleton of, 414. 
Liver, 87. 

in sauropsida, 308. 

Lizard, brain of, 302, 303. 

pectoral arch and sternum, 

35, 36. 
skeleton of visceral arches, 

85. 
Lymphatic system, 100. 
Lymph corpuscles, 101. 



M. 

MACRAUCHENIDiB, 366. 

Mammalia, general characteristics 

of, 114. 

classification, 319. 

deciduate, 411. 

dental formulae, 89. 

development of heart, 99. 

skeleton of visceral arches 

of mammal, 85. 
teeth, 355. 



INDEX. 



505 



Man, arrangement of principal 

vessels in human f cetus, 94. 
— general characteristics of, 488. 

comparison of anthropomor- 

pha with, 487. 

digits of, 31. 

" ■ divisions of :-^ 
Leiotrichi, 497. 
Ulotrichi, 497. 

fossil, 497. 

laws of growth in, 493. 

muscles of digits, 62, 53, 54, 

55, 56. 

muscles of limbs, 48. 

OS innominatum, 37. 

position of limbs, 33. 

* races 'of, 494. 

section of pregnant uterus of 

a deciduate luacental mammal, 
4. 

sexual differences, 493. 

teeth, 89. 

Marmosets. See Arctopithecini. 
Afarsipobranchii, 121. 
Marsupialia, digits of, 326. 
Mastodon, 431. 

Mesozoic formation, crocodiles in, 
258. 

didelphidse, <&c., in, 328. 

lizards in, 226. 

omithoscelida in, 265. 

plesiosauria confined to, 215. 

pterosauria in, 266. 

Miocene epoch, cotylophoraof,385. 

extinct mammals, 376. 

fossil camelidsB, 386. 

fossil equidse, 358, 359. 

fossil hippopotamidae, 376. 

fossil rhmoceros, 363. 

fossil tapirs, 365. 

genus of sirenia, 391. 

Modmcations of the brain, 63. 

of the heart, 97. 

of reproductive organs, 109. 

Moles {tatpincB)j 452. 
Monkeys. See Simiadse. 
Monkfish (smiaiina)j pectoral 
member of, 39. 

sections of skull, 130. 

Monodelphia, characteristics of, 

328. 
Mosasauria, 228. 
Mudfish, 168. 



Muscles of amphibia, 47. 
— antebrachium, 51. 

anthropomorpha, 482. 

crus, 51. 

cynomorpha, 472. 

the digits, 52. 

dog, 417. 

eye in sauropsida, 304. 

fishes, 46. 

hedgehog, 444-446. 

horse, 353. 

the limbs, 48. 

man, 491. 

marmoset, 464. 

ophidia, 299. 

pig, 369.^ 

platyrrhim, 467. 

rabbit, 439. 

seal, 426. 

system of, in ophidia, che- 

lonia, and aves, 299. 

trunk and head, 45. 

Musk deer, stomach of, 379. 
Myelon, 69. 
Myxine, 123. 



N. 

Negroes, peculiarities of, 495. 
Nerves, cerebral, 71. 

of the eje, 79-81. 

sauropida, 301. 

spinal, 69. 

sympathetic, 77. 

Nervous system of frog, 70. 
Non-ruminating animals, 367. 



0. 

Olfactory apparatus, 78. 

nerves, 71. 

Ophidia, groups of, 233. 

f ossU, 242. 

muscular system, 299. 

organs of copulation, 318. 

skull, 235. 

teeth, 242. 

vertebrae, 233. 

Optic nerves, 71, 80, 81. 

OrangSj 476. 

middle digit of, 53. 



506 



INDEX. 



Organs, circulatory, 90. 

of hearing, 81. 

renal, 106. 

reproductive. See Reproduc- 



101. See also 



tive organs. 
respiratory. 

Respiration. 

of sight, 79. 

of taste, 86. 

of touch, 86. 

of voice, 103. 

Omithodelphia, characteristics of, 

320. 
Omithoscelida, 261. 
transitional character of 

skeleton of, 261. 
Os innominatum of man, 37. 
Ossa innominata of the horse, 351. 
Ossification of facial apparatus, 25. 

skull, 21. 

vertebrae, 13. 

Ostrich, reproductive organs of, 

318. 

skull, 284. 

Otaridse (eared-seals), 423. 
Ox, skeleton of, 377. 



P. 

PALiBOTHERIDiS, 365. 

Palate of cetacea, 395. 
Pectoral arch, 34. 

in birds, 289.^ 

chelonia, 206. 

crocodiles^ 256. 

and fore limb of pike, 158. 

of plesiosauria, 213. 

Pectoral fins, 40. 



member of monkfish {squa- 

tina)j 39. 
Pelvic arch, 37. 

of chelonia, 206. 

of plesiosauria, 214. 

Pelvis of anthropomorpha, 480. 

bat, 455. 

birds, 293. 

cetacea, 394. 

crocodiles, 257. 

cynomorpha, 471. 

hedgehog, 444. 

man, 490; lower races of 

man, 495. 



Pelvis of platyrrhini, 466. 

porpoise, 405. 

pterosauria, 269. 

sirenia, 389. 

Permian formation, lizards of, 226 
Perissodactyla, 342. 
Pharyngobranchii, 116. 
Phocidae, general cbiuracteristicf 

of, 424. 
Phocodontia, 411. 
Phytophaga, 330. 
Pig, anatomy of, 367. 

brain, 64-69. 

digital muscles, 56. 

Pike, brain of, 164. 

fins, 42. 

pectoral arch and fore limb 

m 

skull, 151, 152, 154, 155. 



Pinnipedia, chaxacteristics o^ 423. 

groups, 428. 

Pisces. See Fishes. 

" Placoid exoskeleton," 126. 

Plaice, skull of, 29. 

Plastron of the chelonia, 201. 

Platyrrhini, general characteristics 
of, 465. 

Plesiosauria, 208, 215. 

pelvic arch of, 214. 

skeleton, 210. 

extinct, confined to Mesozoic 

rocks, 215. 

Pleuronectidse (flat fishes), 30. 

Polypterus,caudal extremity of ,17. 

Poipoise, general chuacteristics 
of, 402. 

heart, 407. 

muscles, 406. 

pelvis, 405. 

respiratory apparatus, 408. 

skull, 403. 

stomach, 407. 

teeth, 407. 

vertebrae, 403. 

Post-Triassic group of plesio- 
sauria, 215. 

Poupart's ligament, 38. 

Primates, characteristics o^ 457. 

divisions of, 458. 

Proboscidea, gen^nd character- 
istics of, 428. 

bones, 430. 

fossil, 432. 



toides, teproductive organs, 

|»U,428. 
tomHcli, 431. 
Hth, 48a 
iBrteb™, 42a 
bnuria, 22H. 

lactyliie, skeUtoD of, 2GT. 

BiiTm,2e6. 

Mup9 cf, 270. 

knlL 3H8. 

BrtebriE, 2G7. 

PL doTsal vartebra of, 234. 

kull, 23C, 3311. 



spinition, mBchaoiBm of, 104, 

- otgauB of, 101. 
* imphibia, 187. 

— •sea, 40S 
laids, 31 

- Teleootei, 162. 
Khinooetos, general ohanictoria- 



S, uiatomv of, 437. 
nin, 64-69, 440. 
intiil muBclea, G6. 
ImbB, 439, 440. 
uuclee, 430. 
bpruductive aigaai, HI. 
bill,48S. 
»ttb, 441. 
Brteb™, 437. 

Ol mui, 404. 

nculenta, cerebro-apinal u 

ptibetic nervuuB BJ-Blom i 



sctiTB organs, lOQ. 



thropainorplia, 4»7. 
lt,46S. 
lds,31f<. 
K,431. 
dKcbog, 449. 
BiurldB, 4(iO. 
•n, 490, 4!IS, 
odlficadona of, 109. 
Itoic]i,318. 
Wpoisc, 410. 
nropiida, 318. 
m cbarKcUruticB of, 19S. 

DUpB, 1%. 



— porpuises, 40S. 



- Bfcm, 860. 

- skull, 360. 

- teeth, 360, 36% 



viacera, 862. 

RhvncliDcephala, fi6, 
Rodentia, Kensral cbacaclorislica 
of, 434. 

digits, 436. 

reproductive organs, 43(1. 



— teeth, ■-,- 
verlebne, 



, 4sa. 



Itumiosting animals, S; 

act o( feeding, 88U. 

BBt of nimination, 381. 

groups of, BBS. 



Salamasdba, bindfoot of, 82. 
" ' no, caudal cstremity ot 11 

rum of birds, 278. 
Sannipsida, general charactctis 

- alimentary canal of, 807. 

- brain, 302, S03. 

- ear, 806. 



mUBclea and viaoera, 299. 

nerres, 801. 

reproductive organs, 318. 

reflpimtorv organs, 815. 

Btomacb, 808. 

tongue of, 307. 

SaUs. Bee Otatidaa, Fhucidie, 

Secrelsry bird, skull of, 887. 



f' 


^H 


508 ^H 


Sensory orgsnn, 78. 


Sknll of fiBhea, 30. ^H 


Sesnal iliffereiiceB in miin, 493. 


fcBtal cachaloL j^^M 


Sharks, aord.: BTch of, Hi. 


frog, 17B, 176. ^^M 


■ortic bulb, 132. 


— hedBohOff, 443. ^^ 
horse, sS. 


pectoral arch, SI. 


ShBr&r«knll, 21. 


laeertilia. 219, 221, 


Sheep, Htomach of, 379. 


leamridffi.45S. 


ShrewB {Mrieti), 452. 


man, 489 ; dlSereaui in,. 


Simiads, general chwaettristics 




of, 461. 


modifloatiooB o^ 21. 


dirisioas of, 4fi2. 


mndfish, 168, 169. 


skull, 461. 


Dorves of, 71-77. 


teelli,461. 


ophidia, 235. 

ornithoBcelida, 266. 

ostrich, 284. 


Skati. hniin ot 134. 




oaaeooe brain-owe, 21-23 


of anarppoiuorplui, 477. 


pig, 868. 


cBtanhme monkey. 462. 


pike, 151, 152, 154, lit 


chelone midsB, sectiDn of, 


plaice, 29. ^ 


199. 


platvTThiiii, 46a,,^H 


elephant, 439 


plesiosanria, 211^^^M 


flying fox, 453. 

f OBail equids, 358, 359. 

ho CM, 347. 


porpoise, 403. ^^H 

pterosauria, 2ea^^H 


rabbit, 438? ^^W 


icthyoesurifl, 244. 




Umb9,81. 


chmoceroB, 360. 


lion, 414. 


fleol, 42B. 


omithoacelidtt, trtmnitional 


secretary bird, 287. 


character of, 261. 


flireiua,388. 




— apatnlaria, 140. 




sturgeon, 141. 


porjjoiae, 403. 




ptraodao^fluB, 267. 

the BknU, 19. 


rrffi.'ff-"''"- 


viaeeral arehea of lizard, 


whale, 396, 397. 


mammal, and flah, 85. 




See aim EndoakQlcton, Exo- 


ankle-joint. 381. ^ 


Bkeletoii. 


Hmba,331. 


Skull of accipenger, Hi. 




1 amphibian, 177. 




arches belonging to, 77. 

of bat, 455. 




Snakes. Se« (Miidil^^H 
Soricca (ahrtnta), 4&^^^^B 


1 birds, 382. 


Spatularia, skull of, «^H 


carol vora, 412. 


Spinal canal and cord, W^" 


^ common fowl, 283. 


syBtOHl, 11. 


1 celacea, 892. 


Sploen, 101. 


1 chelonia, 303-306. 




cranial system, 18, 


cea, 409. 


— crocodUe, SB4. 


SpuiofbirdB,297. 


1 cynomorpha, 469. 


8q™H|«^^^monkflah), pest. 


1 dog, 415. 




elephant, 438. 


sections ot slmU, ISO. 



INDEX. 



509 



E^ Stenson, canals of, 79. 
^ Sternum in birds, 280, 281. 

of frog, 181. 

of lizard, 35, 36. 

Stomach, 87. 
g — ' — of camels, Ac, 385. 

camivora, 413. 

musk deer, 379. 



porpoise, 407. 



ruminating animals, 378, 379. 

sauropsida, 308. 

sheep, 379. 

teleostei, 160. 

Sturgeon, skull of, 21, 141. 
Suidse, 367. 

variations in, 373. 

Sympathetic nerves, 77. 
Syrinx, 103. 
of birds, 313. 

T. 

Tadpoles, 191, 192. 
Tapirs, characteristics of, 363. 
Tarsus, skeletal elements of, 31. 
Taste, organ of, 86. 
Teeth, 87. 

of amphibia, 182. 

anthropomorpha, 486. 

bat, 466, 466. 

camivora, 412. 

cats, 422. 

cetacea, 394. 

• crocodiles, 258. 

cynomorpha, 473. 

delphinoidea, 399. 

didelphia, 326. 

dog, 418, 422. 

edentata, 330, 336. 

edentata tubulidentata, 337. 

elephant, 430. 

extinct mammals, 376. 

fishes, 129, 159. 

galeopithecus, 461. 

hedgehog, 446. 

hippopotamus, 374. 

horse, 344, 364. 

hyrax, 433. 

lacertilia, 224. 

lemuridse, 460. 

macrauchenidse, 366. 

man, 492, 496. 

marmoset, 463. 



Teeth of ophidia, 242. 

omithoscelida, 266. 

palffiotheridas, 366. 

pig, 371. 



platyrrhini, 467. 

porpoise, 407. 

rabbit, 441. 

rhinoceros, 360. 

rodentia, 434. 

seal, 427. 

sirenia, 389. 

suidae, 367, 373. 

tapirs, 363. 

toxodontia, 386. 

walrus, 424. 

whale, or whalebone, 398. 

Teleostei, 148. 

aortic arch o^ 92. 



Tertiary epoch, extinct cetaceand 
of, 411. 

late, fossil man in, 497. 

Thymus, 101. 

Tongue of amphibia, 183. 

sauropsida, 307. 

sloths, 336. 

Torpedo, electrical apparatus o^ 
68. 

Tortoises, 197. 

Touch, organs of, 86. 

Toxodontia, extinct^ characteris- 
tics of, 386. 

Tragulidae, 382. 

Transition of skeleton of omitho- 
scelida, 261. 

Trematosauras, skull of, 179. 

Triassic formation, crocodiles of, 
258. 

extinct lizards, 226. 

dicynodontia, 261. 

ichthyosauria, 249. 

macropodidae, Ac, 328. 

Triassic groups of plesiosauria, 
215. 

Trichechidse (walruses), 424. 

Trigeminal nerves, 74, 76. 

Trunk and head, muscular system 
of, 46. 

Turkey, brain o^ 302. 

Turtles, 197. 

heart, 309, 310. 

plastron, 202. 

skull, 203-205. 

Tylopoda or camelids, 385. 



' 


^^^^H 


510 ^^^^^1 


TJ. 


Vertebrae of snakes, 933. ^^^| 




tapire, 363. ^^^H 


UT,OTniciii, 497. 


wbalea, 31)5. ^^^M 


UngolaUi, cbamcUriatirs uf, 3^1. 


Veitebrati^ diBtinctive ok^^^H 

of, ^^H 

imiiTefmatiDn, 3. ^^^^^| 


V. 


VampibB bat, 457. 


VKJCulai BystBin, 93-9G. 


limbs, 30. ^ *^P 


Veins, 93. 


proTincea or gronpa, 111 ■ 


Venttal fin a, 40. 






exoskeleton, 40. 1 


bal,464. 


Vehicle* of the brain, 59. 1 


birds, 275. 


camdidee, 3^6. jB^B 


caoclal, 16. 


of carniTora, 412. 


elepbant, 481. ^^^H 


— eetscei, 3D2. 


crocodaes, 250. 


bedgebOR, 44a ^^^H 


cynomorpha, 469. 




^ b^^Eboff, 443. 


bviax, 434. ^^^H 


lemorids, 459. ^^^| 


^ — boraE,346. 


pig, 372. ^^H 


hyiaK, 432. 

iAthyosanria, 243. 


platyrrbini, 467, WSJ^^^M 

— Mit, 441. ^""^^m 


lacertilia, 217. 


rodsntia, 438. ^^^H 


— IcmaiidE,459. 


s«tl. 427. ^^^H 


man, 488 ; lower races of, 495. 


tapirs, 365. ^^^H 

Vieceral arches and clefU^^^^^I 






areb<>s, Bkeletons of, ^^^^H 




Voice of birds, 318. '^^^H 
organs of, 103. ^^H 


of i>ig, 3fi7. 


plotvrrhine, 4C5. 




[,«r,;oi.., 41)3. 

■ proboBtiden, 423. 


^^^1 


pteroaanria, 2G7. 




rabbit, 437. 


Whalebone, S9S. ^^^H 




Wbnle, ear-bones of, 3»T.,^^^H 


rodenfia, 435. 


sknllof,397. ^^^1 


seal, 425. 


ekuU of fcotal, 396. ^^^H 


Biraiifl, 388. 


sperm, bead of, 400, ^^^^H 




OI'IU! AKD WtS, fTAUHHUl STMl^^^H 


Iniiili 





By the same Author, 

INTKODUCTION TO THE CLASSIFICATION 

OF ANIMALS. 

With Engravings. 8vo. 6«. 



' la /Sa|f 



B1505 Huxley, T.H. 7759 
H9S Manual of the anatonj 
M871 of veptfthrntfiri finlmHl« 




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